Light-emitting diode, method for manufacturing the same, and display device including the light-emitting diode

Abstract

A light-emitting diode according to an embodiment of the present disclosure includes a first electrode; a second electrode opposite to the first electrode; an emission layer between the first electrode and the second electrode, the emission layer including quantum dots; a first charge transfer layer between the first electrode and the emission layer; a second charge transfer layer between the second electrode and the emission layer; and an insulating layer at at least one position between the first charge transfer layer and the emission layer and / or between the second charge transfer layer and the emission layer, wherein the insulating layer includes an inorganic material. The light-emitting diode and a display device including the light-emitting diode exhibit improved lifetime characteristics and emission efficiency properties.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority and benefit of Korean Patent Application No. 10 - 2019 - 0034517, filed on Mar. 26, 2019, the entire contents of which are incorporated herein by reference. Technical field

[0003] One or more aspects of embodiments of the present disclosure relate to light - emitting diodes, methods of manufacturing the same, and display devices including the light - emitting diodes, and more particularly, to light - emitting diodes having improved luminous efficiency, methods of manufacturing the same, and display devices including the light - emitting diodes. Background art

[0004] Various display devices are being developed for use in multimedia devices such as, for example, televisions, mobile phones, tablet computers, navigators, and / or game consoles. In such display devices, self - emissive display devices that display images by irradiating a light - emitting material including an organic compound may be used.

[0005] To improve the color reproducibility of display devices, the development of light - emitting diodes using quantum dots as light - emitting materials is being carried out, and improvement in the reliability and lifespan of light - emitting diodes using quantum dots is required (or desired). Summary of the invention

[0006] One or more aspects of embodiments of the present disclosure relate to a light - emitting diode in which an insulating layer is adjacent to an emission layer including quantum dots, the light - emitting diode having improved lifespan and luminous efficiency; and a display device including the light - emitting diode.

[0007] One or more aspects of embodiments of the present disclosure also provide a method of manufacturing a light - emitting diode, by which an insulating layer having uniform and improved layer quality can be provided through an improved process.

[0008] Embodiments of the inventive concept provide a light - emitting diode including a first electrode; a second electrode opposite the first electrode; an emission layer between the first electrode and the second electrode, the emission layer including quantum dots; a first charge transfer layer between the first electrode and the emission layer; a second charge transfer layer disposed between the second electrode and the emission layer; and an insulating layer positioned (e.g., in a certain position) between the first charge transfer layer and the emission layer and / or between the second charge transfer layer and the emission layer. The insulating layer includes an inorganic material.

[0009] In one or more embodiments, the insulating layer may include a material selected from SiNx , SiO x , Al2O3, TiO x and ZrO x (0.1 ≤ x ≤ 2.0), at least one of them.

[0010] In one or more embodiments, the insulating layer may include an inorganic insulating layer containing an inorganic material and an organic insulating layer containing an organic material.

[0011] In one or more embodiments, the insulating layer may include a plurality of the inorganic insulating layers containing the inorganic material and a plurality of the organic insulating layers containing the organic material, and the plurality of inorganic insulating layers and the plurality of organic insulating layers may be alternating in the insulating layer.

[0012] In one or more embodiments, the organic insulating layer may contain at least one selected from n-hexane, furan, and hexamethyldisiloxane.

[0013] In one or more embodiments, the first charge transfer layer may include a hole injection layer adjacent to the first electrode, and a hole transport layer between the hole injection layer and the emission layer. The second charge transfer layer may include an electron injection layer adjacent to the second electrode, and an electron transport layer between the electron injection layer and the emission layer.

[0014] In one or more embodiments, the quantum dots may include cadmium-based materials, and the insulating layer may be between the electron transport layer and the emission layer.

[0015] In one or more embodiments, the insulating layer may include a first insulating layer between the first charge transfer layer and the emission layer, and a second insulating layer between the second charge transfer layer and the emission layer.

[0016] In one or more embodiments, the first insulating layer and the second insulating layer may have different thicknesses.

[0017] In one or more embodiments, the emission layer may contain a plurality of quantum dots, and a matrix component in which the plurality of quantum dots are dispersed. The plurality of quantum dots may form 1 to 10 layers in the emission layer.

[0018] In one or more embodiments, the insulating layer may contact the emission layer.

[0019] In one or more embodiments, the thickness of the insulating layer may be about 0.1 nm to about 10 nm.

[0020] In one or more embodiments of the inventive concept, a display device includes a plurality of light emitting diodes. Each light emitting diode includes a first electrode; a second electrode opposite to the first electrode; an emission layer between the first electrode and the second electrode and including quantum dots; a first charge transfer layer between the first electrode and the emission layer; a second charge transfer layer between the second electrode and the emission layer; and an insulating layer between the first charge transfer layer and the emission layer and / or between the second charge transfer layer and the emission layer. The insulating layer includes an inorganic material.

[0021] In one or more embodiments, the light emitting diodes may include a first light emitting diode including first quantum dots to emit first color light, a second light emitting diode including second quantum dots to emit second color light having a wavelength longer than that of the first color light, and a third light emitting diode including third quantum dots to emit third color light having a wavelength longer than that of the second color light.

[0022] In one or more embodiments, the display device may further include a light control layer on the light emitting diodes.

[0023] In one or more embodiments, the insulating layer may include a plurality of inorganic insulating layers and a plurality of organic insulating layers. The plurality of inorganic insulating layers and the plurality of organic insulating layers may be alternating in the insulating layer.

[0024] In one or more embodiments of the inventive concept, a method of manufacturing a light emitting diode includes: forming an emission layer including quantum dots on a first electrode, forming an insulating layer by depositing an inorganic material on the emission layer, and forming a second electrode on the insulating layer.

[0025] In one or more embodiments, the forming of the insulating layer may include depositing the inorganic material by atomic layer deposition (ALD).

[0026] In one or more embodiments, the forming of the insulating layer may include forming an inorganic insulating layer by depositing the inorganic material, and forming an organic insulating layer by depositing an organic material. The forming of the inorganic insulating layer and the forming of the organic insulating layer are performed alternately and multiple times.

[0027] In one or more embodiments, the forming of the organic insulating layer may include depositing the organic material by chemical vapor deposition (CVD). Description of the Drawings

[0028] The drawings are included to provide a further understanding of the inventive concept and are incorporated into and form a part of this specification. The drawings illustrate exemplary embodiments of the inventive concept and, together with the description, are used to explain the principles of the inventive concept. In the drawings:

[0029] Figure 1 is a perspective view of an electronic device according to an embodiment of the inventive concept;

[0030] Figure 2 is a cross-sectional view of a display device according to an embodiment of the inventive concept;

[0031] Figure 3A is a cross-sectional view of a light-emitting diode according to an embodiment of the inventive concept;

[0032] Figure 3B is a cross-sectional view showing some elements of a light-emitting diode according to an embodiment of the inventive concept;

[0033] Figures 4 to 9 is a cross-sectional view of a light-emitting diode according to an embodiment of the inventive concept;

[0034] Figure 10 is a plan view of a display device according to an embodiment of the inventive concept;

[0035] Figure 11 and Figure 12 is a cross-sectional view of a display device according to an embodiment of the inventive concept;

[0036] Figure 13 is a flowchart showing a method of manufacturing a light-emitting diode according to an embodiment of the inventive concept; and

[0037] Figures 14A to 14E is a cross-sectional view showing operations of a method of sequentially manufacturing a light-emitting diode according to an embodiment of the inventive concept. DETAILED DESCRIPTION

[0038] Hereinafter, embodiments of the inventive concept will be explained in more detail with reference to the drawings. The inventive concept may be implemented in different forms and may have various modifications, and exemplary embodiments of the inventive concept will be described in more detail below with reference to the drawings. However, the inventive concept should not be construed as being limited to the embodiments set forth herein. Instead, these embodiments should be understood to include modifications, equivalents, and / or alternatives within the spirit and scope of the inventive concept.

[0039] In the drawings, like reference numerals refer to like elements throughout. For clarity of illustration, the dimensions of the enlarged structures are shown. It is to 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 only used to distinguish one element from another. Thus, a first element may be referred to as a second element without departing from the teachings of the present invention. Similarly, a second element may be referred to as a first element. As used herein, the singular forms are intended to also include the plural forms unless the context clearly indicates otherwise.

[0040] It should be further understood that when the terms "includes", "including", "comprises", and / or "comprising" are used in this specification, they specify the presence of the stated features, integers, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

[0041] In the present disclosure, when a layer, film, region, plate, etc. is referred to as being "on" or "above" another component, it may be "directly on" the other component, or there may also be intervening elements (e.g., layers). Similarly, it should be understood that when a layer, film, region, plate, etc. is referred to as being "under" or "beneath" another component, it may be "directly under", and there may also be one or more intervening elements (e.g., layers). In addition, it should also be understood that when a plate is referred to as being "above" another component, it may be disposed (located) above or below the other component.

[0042] Meanwhile, the term "direct contact" (or, for example, "directly on" or "directly under") in the present disclosure may mean that there is no additional layer, film, region, plate, etc. between components such as layers, films, regions, plates, etc. For example, when an element is referred to as being "in direct contact" with another element, the two elements (e.g., two layers or two units) are disposed adjacent to each other without using an additional unit, such as an adhesion unit therebetween.

[0043] Hereinafter, a display device and a light emitting diode according to one or more embodiments of the present inventive concept will be explained with reference to the accompanying drawings.

[0044] Figure 1 is a perspective view of an electronic device ED according to an embodiment of the present inventive concept. Figure 2 is a cross-sectional view of a display device DD according to an embodiment of the present inventive concept. Figure 2 corresponds to Figure 1 the cross-sectional view taken along line I-I' in Figure 3AA cross-sectional view of a light-emitting diode EE according to an embodiment of the inventive concept. Figure 3B A cross-sectional view showing some components of a light-emitting diode EE according to an embodiment of the inventive concept.

[0045] In one or more embodiments, the electronic device ED may be a large electronic device, such as a television, a monitor, and / or an external advertising board. Additionally, the electronic device ED may be a small electronic device or a medium-sized electronic device, such as a personal computer, a laptop computer, a personal digital terminal, a car navigation unit, a game console, a portable phone, a tablet computer, and / or a camera. However, these exemplary devices are presented for illustrative purposes only, and other electronic devices may be employed.

[0046] The electronic device ED may include a display device DD and a housing HAU. The display device DD may display an image IM through a display surface IS. Figure 1 It is shown that the display surface IS is parallel to a surface defined by a first direction DR1 and a second direction DR2 intersecting the first direction DR1. However, this is illustrative, and in other embodiments, the display surface IS of the display device DD may have a curved shape.

[0047] The thickness direction of the display device DD (e.g., the direction of the displayed image IM) is orthogonal to the display surface IS and is represented by a third direction DR3. The front surface (or top surface) and the rear surface (or bottom surface) of each component may be separated (e.g., spaced apart from each other) along the third direction DR3.

[0048] A fourth direction DR4 may be a direction between the first direction DR1 and the second direction DR2. The fourth direction DR4 vector may lie in a plane parallel to the plane defined by the first direction DR1 and the second direction DR2. However, the directions represented by the first to fourth directions (DR1, DR2, DR3, and DR4) are relative and may be changed to other directions.

[0049] The housing HAU may be configured to receive the display device DD. The housing HAU may be arranged to cover the display device DD such that the top surface of the display surface IS of the display device DD is exposed. For example, the housing HAU may cover the side surfaces and the bottom surface of the display device DD and may expose the entire top surface. However, the embodiments of the inventive concept are not limited thereto, and the housing HAU may cover a part of the top surface of the display device DD as well as the side surfaces and the bottom surface.

[0050] 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 includes a light-emitting diode EE (see Figure 11)). The display device DD may include a plurality of light-emitting diodes EE. The light control layer PP may be disposed on the display panel DP and may control external light to control the reflected light from the display panel DP. The light control layer PP may include, for example, a polarization layer and / or a color filter layer.

[0051] Figure 3A is a diagram showing the light-emitting diode EE according to an embodiment, and with reference to Figure 3A , the light-emitting diode EE according to the embodiment includes a first electrode EL1, a second electrode EL2 opposite to the first electrode EL1, and an emission layer EML disposed between the first electrode EL1 and the second electrode EL2. A first charge transfer layer CTL1 is disposed between the first electrode EL1 and the emission layer EML. A second charge transfer layer CTL2 is disposed between the second electrode EL2 and the emission layer EML.

[0052] An insulating layer ISL is disposed between the first charge transfer layer CTL1 and the emission layer EML and / or between the second charge transfer layer CTL2 and the emission layer EML. Figure 3A An embodiment is illustrated in which the insulating layer ISL is disposed between the second charge transfer layer CTL2 and the emission layer EML. However, the insulating layer ISL may be disposed between the first charge transfer layer CTL1 and the emission layer EML without limitation. In one or more embodiments, the insulating layer ISL may be respectively disposed between the first charge transfer layer CTL1 and the emission layer EML, and between the second charge transfer layer CTL2 and the emission layer EML.

[0053] The emission layer EML contains quantum dots QD. The emission layer EML may have a shape in which a plurality of quantum dots QD are dispersed in the matrix component HS. The core of the quantum dot QD may be selected from compounds of Group II-IV, compounds of Group III-V, compounds of Group IV-VI, elements in Group IV, compounds of Group IV, and combinations thereof.

[0054] Compounds of the II-VI group may be selected from: binary compounds selected from CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS and mixtures thereof; ternary compounds selected from AgInS, CuInS, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS and mixtures thereof; and quaternary compounds selected from HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe and mixtures thereof.

[0055] Compounds of the III-V group may be selected from: binary compounds selected from GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb and mixtures thereof; ternary compounds selected from GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InNP, InNAs, InNSb, InPAs, InPSb and mixtures thereof; and quaternary compounds selected from GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb and mixtures thereof.

[0056] Compounds of the IV-VI group may be selected from: binary compounds selected from SnS, SnSe, SnTe, PbS, PbSe, PbTe and mixtures thereof; ternary compounds selected from SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe and mixtures thereof; and quaternary compounds selected from SnPbSSe, SnPbSeTe, SnPbSTe and mixtures thereof. The element in the IV group may be selected from Si, Ge and mixtures thereof. The compound of the IV group may be a binary compound selected from SiC, SiGe and mixtures thereof.

[0057] In one or more embodiments, binary compounds, ternary compounds, and / or quaternary compounds may be present in the particles at a uniform concentration, or may be present in the same particle in a partially different concentration distribution state. In addition, a core-shell structure in which one quantum dot surrounds another quantum dot may be possible. The interface between the core and the shell may have a concentration gradient, in which the concentration of the elements present in the shell decreases toward the center.

[0058] In some embodiments, the quantum dot QD may have a core-shell structure including a core containing nanocrystals and a shell surrounding the core. The shell of the quantum dot QD having the core-shell structure may serve as a protective layer for preventing or reducing chemical deformation of the core to maintain semiconductor properties, and / or a charging layer for imparting electrophoretic properties to the quantum dot QD. The shell may have a single layer or multiple layers. The interface between the core and the shell may have a concentration gradient, in which the concentration of the elements present in the shell decreases toward the center. Examples of the shell of the quantum dot QD having the core-shell structure may include metals, non-metal oxides, semiconductor compounds, and combinations thereof.

[0059] For example, the metal and the non-metal oxide may each independently include binary compounds (such as SiO2, Al2O3, TiO2, ZnO, MnO, Mn2O3, Mn3O4, CuO, FeO, Fe2O3, Fe3O4, CoO, Co3O4, and / or NiO) and / or ternary compounds (such as MgAl2O4, CoFe2O4, NiFe2O4, and / or CoMn2O4), but the embodiments of the inventive concept are not limited thereto.

[0060] In one or more embodiments, the semiconductor compound may include 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 of the inventive concept are not limited thereto.

[0061] The quantum dot QD may have a full width at half maximum (FWHM) of an emission wavelength spectrum of about 45 nm or less than 45 nm, for example, about 40 nm or less than 40 nm, and in some embodiments, about 30 nm or less than 30 nm. Within this range, color purity and / or color reproducibility may be improved. In addition, the light emitted by such quantum dots is emitted in all directions, and the viewing angle of the light may be improved.

[0062] The shape of the quantum dot QD can be any suitable shape and is not particularly limited. For example, the quantum dot QD can have a spherical, conical, multi-armed, and / or cubic nanoparticle, nanotube, nanowire, nanofiber, nanoplate particle shape, etc.

[0063] The quantum dot QD can control the color of the emitted light according to the average diameter of the particles, and thus, the quantum dot QD can have various emission colors, such as blue, red, and / or green. As the average diameter of the particles of the quantum dot QD decreases, light in the short wavelength region can be emitted. For example, the average diameter of the quantum dot emitting green light can be smaller than the average diameter of the quantum dot emitting red light. In addition, the average diameter of the quantum dot emitting blue light can be smaller than the average diameter of the quantum dot emitting green light.

[0064] In the present disclosure, the average diameter can refer to the arithmetic mean of the diameters of a plurality of quantum dot particles. For example, the diameter of the quantum dot particle can be the average of the widths of the quantum dot particle in the cross-section.

[0065] In the light-emitting diode EE of the embodiment, the emission layer EML can include a host and a dopant. In one or more embodiments, the matrix component HS of the emission layer EML can include a host material and can include quantum dots QD as a dopant material.

[0066] In the light-emitting diode EE of one or more embodiments, the emission layer EML can emit fluorescence. For example, the quantum dot QD can be used as a fluorescent dopant material.

[0067] The emission wavelength of the light emitted from the emission layer EML can be changed according to the type (or kind) of the quantum dot QD used. Depending on the type (or kind) of the quantum dot QD, the light emitted from the emission layer EML can be blue light, green light, or red light.

[0068] The quantum dots QD dispersed in the matrix component can be applied by using one or more suitable methods (such as vacuum deposition method, spin coating method, casting method, Langmuir-Blodgett (LB) method, inkjet printing method, laser printing method, and / or laser-induced thermal imaging (LITI) method) to form the emission layer EML.

[0069] The quantum dots QD included in the emission layer EML can be laminated into one or more layers. In one or more embodiments, as Figure 3AAs shown, the quantum dots QD can be laminated into two layers in the emission layer EML. However, embodiments of the inventive concept are not limited thereto, and the quantum dots QD can be laminated into one to ten layers. Depending on the type (or kind) of quantum dots QD used and the desired emission wavelength of light, the quantum dots QD can be laminated into any suitable number of layers.

[0070] In the light-emitting diode EE of one or more embodiments, the emission layer EML may further include any suitable anthracene-based light-emitting material.

[0071] The emission layer EML may further include any suitable host material. For example, in one or more embodiments, the emission layer EML may include tris(8-hydroxyquinolinato)aluminum (Alq3), 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP), poly(N-vinylcarbazole) (PVK), 9,10-bis(naphthalen-2-yl)anthracene (ADN), 4,4',4''-tris(carbazol-9-yl)-triphenylamine (TCTA), 1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene (TPBi), 3-tert-butyl-9,10-bis(naphthalen-2-yl)anthracene (TBADN), stilbene-substituted arylide (DSA), 4,4'-bis(9-carbazolyl)-2,2'-dimethyl-biphenyl (CDBP), 2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN), bis[2-(diphenylphosphino)phenyl]ether oxide (DPEPO), hexaphenylcyclotriphosphazene (CP1), 1,4-bis(triphenylsilyl)benzene (UGH2), hexaphenylcyclotrisiloxane (DPSiO3), octaphenylcyclotetrasiloxane (DPSiO4), 2,8-bis(diphenylphosphoryl)dibenzofuran (PPF), 3,3'-bis(N-carbazolyl)-1,1'-biphenyl (mCBP), 1,3-bis(N-carbazolyl)benzene (mCP), etc. as host materials. However, embodiments of the inventive concept are not limited thereto, and one or more suitable host materials may be included in addition to the host materials described above.

[0072] In the light-emitting diode EE of one or more embodiments, the emission layer EML may further include a dopant. For example, the emission layer EML may include styryl derivatives (e.g., 1,4-bis[2-(3-N-ethylcarbazolyl)vinyl]benzene (BCzVB), 4-(di-p-tolylamino)-4'-[(di-p-tolylamino)styryl]diphenylstyrene (DPAVB), and / or N-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl)naphthalen-2-yl)vinyl)phenyl)-N-phenylaniline (N-BDAVBi)), perylene and / or its derivatives (e.g., 2,5,8,11-tetra-tert-butylperylene (TBP)), pyrene and / or its derivatives (e.g., 1,1-dipyrene, 1,4-dipyrenylbenzene, and / or 1,4-bis(N,N-diphenylamino)pyrene), etc. as dopants.

[0073] Figure 3B FIG. is a diagram showing an insulating layer ISL included in a light-emitting diode according to one or more embodiments. In one or more embodiments, the insulating layer ISL includes an inorganic material. The insulating layer ISL may include at least one inorganic insulating layer ISL-IOL1 including an inorganic material. The inorganic insulating layer ISL-IOL1 may be formed by atomic layer deposition (ALD).

[0074] The inorganic material included in the insulating layer ISL may be selected from SiN x , SiO x , Al2O3, TiO x and ZrO x (0.1 ≤ x ≤ 2.0), at least one of which. However, the inorganic material included in the insulating layer ISL may be any suitable material, without limitation, as long as it is a transparent material that does not block the light generated by the light-emitting diode and can achieve the charge balance improvement effect of the light-emitting diode described later.

[0075] The insulating layer ISL may include at least one organic insulating layer ISL-OL1 including an organic material. The organic insulating layer ISL-OL1 may be formed by chemical vapor deposition (CVD).

[0076] The organic material included in the organic insulating layer ISL-OL1 may be selected from at least one of n-hexane, furan, and hexamethyldisiloxane. However, the organic material included in the organic insulating layer ISL-OL1 may be any suitable material as long as it is a transparent material that does not block the light generated by the light-emitting diode and can flatten the emission layer EML of the light-emitting diode to improve the barrier performance.

[0077] The insulating layer ISL may include a plurality of inorganic insulating layers ISL-IOL1 to ISL-IOLn+1 and a plurality of organic insulating layers ISL-OL1 to ISL-OLn. The plurality of inorganic insulating layers ISL-IOL1 to ISL-IOLn+1 and the plurality of organic insulating layers ISL-OL1 to ISL-OLn may be alternately disposed. In Figure 3B , a case where the inorganic insulating layer ISL-IOL1 and the inorganic insulating layer ISL-IOLn+1 are respectively disposed at the lowermost layer and the uppermost layer of the insulating layer ISL is shown as an embodiment, but embodiments of the inventive concept are not limited thereto. For example, an organic insulating layer may be disposed as at least one of the lowermost layer and the uppermost layer of the insulating layer ISL.

[0078] In a light-emitting diode according to one or more embodiments of the inventive concept, the insulating layer may be disposed between the emission layer and the charge transfer layer, and may improve the charge balance of the light-emitting diode and may improve the light emission properties of the light-emitting diode.

[0079] More particularly, in a light-emitting diode including quantum dots as a light-emitting material, the energy level of hole injection and the energy level of electron injection to the emission layer may be different. In this case, an imbalance may occur between the amounts of holes and electrons injected into the emission layer, and the lifetime and emission efficiency of the device may be reduced. According to the inventive concept, the insulating layer may be disposed between the emission layer and the charge transfer layer such that one side of holes or electrons is not excessively injected (considering the difference between the hole injection energy level and the electron injection energy level) into the emission layer including quantum dots as a light-emitting material. Accordingly, the amounts of holes and electrons injected into the emission layer may be controlled to be balanced, and thus, the emission properties of the light-emitting diode may be improved.

[0080] Particularly, according to one or more embodiments of the inventive concept, by forming the insulating layer by depositing an inorganic material by an atomic layer deposition (ALD) method, the insulating layer may be uniformly formed to have a smaller thickness as compared to coating an organic material. In addition, in an emission layer in which quantum dots are disposed in a plurality of layers, although the quantum dots are unevenly laminated in some regions, the top portion of the emission layer is covered with an inorganic insulating layer and charge transfer may be more uniformly achieved. Accordingly, the stability of the device may be improved.

[0081] For example, in the light-emitting diode according to the inventive concept, an insulating layer formed by alternately disposing an inorganic insulating layer and an organic insulating layer may be included. In this case, by (e.g., by including) the inorganic insulating layer uniformly formed to have a relatively small thickness, due to the inorganic layer having excellent (or suitable) layer quality, the charge balance of holes and electrons injected into the emission layer may be appropriately controlled, and by (e.g., by including) the organic insulating layer capable of flattening the top portion of the emission layer, the charge balance control property of the insulating layer may be improved.

[0082] The insulating layer ISL may have a thickness of about 0.1 nm to about 10 nm. If the insulating layer ISL is less than about 0.1 nm thick, it may be difficult to achieve an improvement in charge balance control of the emission layer, and if the insulating layer ISL is greater than about 10 nm thick, the charge injection property from the charge transfer layer to the emission layer may deteriorate.

[0083] Figures 4 to 9 is a cross-sectional view of light-emitting diodes EE-1, EE-2, EE-3, EE-4, EE-5, and EE-6 according to an embodiment of the inventive concept. Hereinafter, various embodiments of the light-emitting diode according to the inventive concept will be described with reference to Figures 4 to 9 When combined with Figure 3A and Figure 3B are described, the same reference numerals will be assigned to the same components, and repeated explanations will not be provided.

[0084] Referring to Figure 4 , the light-emitting diode EE-1 according to an embodiment includes a first electrode EL1, a second electrode EL2 opposite to the first electrode EL1, and an emission layer EML disposed between the first electrode EL1 and the second electrode EL2, and the light-emitting diode EE-1 may include a hole transport region HTR disposed between the first electrode EL1 and the emission layer EML, and an electron transport region ETR disposed between the emission layer EML and the second electrode EL2. An insulating layer ISL-1 may be disposed between the emission layer EML and the electron transport region ETR. The insulating layer ISL-1 may be disposed in contact with the emission layer EML. The light-emitting diode EE-1 may be a top-emitting light-emitting diode.

[0085] The hole transport region HTR and the electron transport region ETR may each include a plurality of sub-organic layers. For example, the hole transport region HTR may include a hole injection layer HIL and a hole transport layer HTL as sub-organic layers, and the electron transport region ETR may include an electron injection layer EIL and an electron transport layer ETL as sub-organic layers. However, embodiments of the inventive concept are not limited thereto, and the hole transport region HTR may further include an electron blocking layer as a sub-organic layer, and the electron transport region ETR may further include a hole blocking layer as a sub-organic layer.

[0086] In the light-emitting diode EE-1 according to an embodiment, the first electrode EL1 has conductivity. The first electrode EL1 may be formed of a metal alloy and / or a conductive compound. The first electrode EL1 may be an anode. The first electrode EL1 may be a pixel electrode.

[0087] In the light-emitting diode EE-1 according to an embodiment, the first electrode EL1 may be a reflective electrode. However, embodiments of the inventive concept are not limited thereto. For example, the first electrode EL1 may be a transmissive electrode or a semi-transmissive reflective electrode. If the first electrode EL1 is a semi-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, a compound thereof, or a mixture 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 layer and / or a semi-transmissive reflective layer formed of any of the above-described materials, and a transparent conductive layer formed of 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 layer and may have a laminated structure of ITO / Ag / ITO.

[0088] The hole transport region HTR may be disposed on the first electrode EL1. The hole transport region HTR may include a hole injection layer HIL and a hole transport layer HTL. 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 further include at least one selected from a hole buffer layer and an electron blocking layer. The hole buffer layer may compensate for an optical resonance distance according to a wavelength of light emitted from the emission layer EML and may increase light emission efficiency. Any material that may be included in the hole transport region HTR may be used as a material that may be included in the hole buffer layer. The electron blocking layer may block or reduce electron injection from the electron transport region ETR to the hole transport region HTR.

[0089] The hole transport region HTR can have a single layer formed of a single material, a single layer formed of multiple different materials, or a multilayer structure including multiple layers formed of multiple different materials. For example, the hole transport region HTR can have a structure of a single layer formed of multiple different materials, or a structure of a 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 laminated from the first electrode EL1, without limitation.

[0090] The hole transport region HTR can be formed using one or more suitable methods (such as vacuum deposition method, spin coating method, casting method, Langmuir-Blodgett (LB) method, inkjet printing method, laser printing method, and / or laser-induced thermal imaging (LITI) method).

[0091] The hole injection layer HIL can include, for example, phthalocyanine compounds (such as copper phthalocyanine); N,N'-diphenyl-N,N'-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4'-diamine (DNTPD), 4,4',4''-tris(3-methylphenylphenylamino)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-styrenesulfonate) (PEDOT / PSS), polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), polyaniline / camphorsulfonic acid (PANI / CSA), polyaniline / poly(4-styrenesulfonate) (PANI / PSS), N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine (NPB), triphenylamine-containing polyether ketone (TPAPEK), 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate, and / or dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN).

[0092] The hole transport layer (HTL) may include carbazole derivatives (such as N-phenylcarbazole and / or polyvinylcarbazole), fluorine 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'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine (NPB), 4,4'-cyclohexylidenebis[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.

[0093] In the light-emitting diode EE-1 of the embodiment, the electron transport region (ETR) may be disposed on the emission layer (EML). The electron transport region (ETR) may include at least one selected from a hole blocking layer, an electron transport layer (ETL), and an electron injection layer (EIL). However, the embodiments of the inventive concept are not limited thereto.

[0094] The electron transport region (ETR) may have a single layer formed of a single material, a single layer formed of a plurality of different materials, or a multi-layer structure having a plurality of layers formed of a plurality of different materials.

[0095] For example, the electron transport region (ETR) may have a structure of a single layer (such as an electron injection layer (EIL) or an electron transport layer (ETL)), and may have a structure of a single layer formed of an electron injection material and an electron transport material. In one or more embodiments, the electron transport region (ETR) may have a single layer structure including a plurality of different materials, or a structure of an electron transport layer (ETL) / electron injection layer (EIL) laminated from the emission layer (EML), or a hole blocking layer / electron transport layer (ETL) / electron injection layer (EIL), without limitation. The thickness of the electron transport region (ETR) may be, for example, about to about

[0096] The electron transport region (ETR) may be formed using one or more suitable methods (such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) method, inkjet printing, laser printing, and / or laser-induced thermal imaging (LITI) method).

[0097] If the electron transport region ETR includes an electron transport layer ETL, the electron transport layer ETL may include an anthracene-based compound. However, embodiments of the inventive concept are not limited thereto, and the electron transport layer ETL may include, for example, tris(8-hydroxyquinolinato)aluminum (Alq3), 1,3,5-tris[(3-pyridinyl)-phenyl-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-benzo[d]imidazol-2-yl)benzene (TPBi), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), 3-(4-biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD), bis(2-methyl-8-quinolinato-N1,O8)-(1,1'-biphenyl-4-yl)aluminum (BAlq), bis(benzoquinolinato-10-beryllium) (Bebq2), 9,10-di(naphthalen-2-yl)anthracene (ADN), or a mixture thereof. The thickness of the electron transport layer ETL may be about to about and may be, for example, about to about If the thickness of the electron transport layer ETL satisfies the range described above, satisfactory (or appropriate) electron transport properties can be obtained without a significant increase in the driving voltage.

[0098] If the electron transport region ETR includes an electron injection layer EIL, the electron injection layer EIL may include LiF, lithium quinolate (LiQ), Li2O, BaO, NaCl, CsF, lanthanide metals (such as Yb) and / or metal halides (such as RbCl and / or RbI). However, embodiments of the inventive concept are not limited thereto. A mixture material of an electron transport material and an insulating organic metal salt may also be used to form the electron injection layer EIL. For example, the organic metal salt may include metal acetates, metal benzoates, metal acetoacetates, metal acetylacetonates, and / or metal stearates. The thickness of the electron injection layer EIL may be about to about For example, about to about If the thickness of the electron injection layer EIL satisfies the range described above, satisfactory (or appropriate) electron injection properties can be obtained without causing a significant increase in the driving voltage.

[0099] The electron transport region ETR may include a hole blocking layer as described above. The hole blocking layer may include, for example, at least one selected from 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and 4,7-diphenyl-1,10-phenanthroline (Bphen). However, embodiments of the inventive concept are not limited thereto.

[0100] The second electrode EL2 is disposed on the electron transport region ETR. The second electrode EL2 may be a common electrode or a cathode. The second electrode EL2 may be a transmissive electrode, a semi-transmissive reflective electrode, or a reflective electrode. If the second electrode EL2 is a transmissive electrode, the second electrode EL2 may include a transparent metal oxide, for example, ITO, IZO, ZnO, ITZO, etc.

[0101] If the second electrode EL2 is a semi-transmissive reflective electrode or a 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, their compounds, or a mixture thereof (for example, a mixture of Ag and Mg). In one or more embodiments, the second electrode EL2 may have a multilayer structure including a reflective layer or a semi-transmissive reflective layer formed using any of the materials described above, and a transparent conductive layer formed using any one of ITO, IZO, ZnO, ITZO, etc.

[0102] The second electrode EL2 may be connected to an auxiliary electrode. If the second electrode EL2 is connected to the auxiliary electrode, the resistance of the second electrode EL2 may be reduced.

[0103] In one or more embodiments, the quantum dots included in the light-emitting diode EE-1 may include cadmium-based materials. The light-emitting diode EE-1 may include any one compound selected from CdSe, CdTe, CdSeS, CdSeTe, CdSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, and CdHgSTe as a light-emitting material. In this case, the emission layer EML of the light-emitting diode EE-1 may have an electron injection property higher than a hole injection property. Accordingly, in the light-emitting diode EE-1 according to an embodiment of the inventive concept, the insulating layer ISL may be included between the electron transport region ETR and the emission layer EML, and may prevent or reduce an excessive injection of electrons from the electron transport region ETR to the emission layer EML. Accordingly, the amounts of holes and electrons injected into the emission layer including cadmium-based quantum dots as a light-emitting material may offset each other, and thus, the light emission property of the light-emitting diode EE-1 may be improved.

[0104] Reference Figure 5 , in the light-emitting diode EE-2 according to an embodiment, the insulating layer ISL-2 may be disposed between the hole transport region HTR and the emission layer EML. The insulating layer ISL-2 may be disposed to be in contact with the emission layer EML. By disposing the insulating layer ISL-2 between the hole transport region HTR and the emission layer EML, an excessive injection of holes from the hole transport region HTR to the emission layer EML may be prevented or reduced. More specifically, depending on the type of the quantum dots QD included in the emission layer EML, the hole injection property may be higher than the electron injection property, but due to the insulating layer ISL-2 disposed between the hole transport layer HTL and the emission layer EML, the amounts of the injected holes and electrons are controlled to reach an equilibrium (e.g., offset each other), and the light emission property of the light-emitting diode EE-2 may be improved.

[0105] Reference Figure 6 , in the light-emitting diode EE-3 according to an embodiment, the insulating layer ISL-3 may include a plurality of layers. For example, the insulating layer ISL-3 may include a first insulating layer ISL-31 and a second insulating layer ISL-32. The first insulating layer ISL-31 may be disposed between the emission layer EML and the electron transport region ETR, and the second insulating layer ISL-32 may be disposed between the emission layer EML and the hole transport region HTR. Each of the first insulating layer ISL-31 and the second insulating layer ISL-32 may be disposed to be in contact with the emission layer EML.

[0106] The first insulating layer ISL-31 and the second insulating layer ISL-32 may each independently contain an inorganic material and an organic material. The first insulating layer ISL-31 and the second insulating layer ISL-32 may each independently include an inorganic insulating layer containing an inorganic material and an organic insulating layer containing an organic material, and a plurality of inorganic insulating layers and a plurality of organic insulating layers may be alternately disposed in a corresponding one of the first insulating layer ISL-31 and the second insulating layer ISL-32.

[0107] The first insulating layer ISL-31 and the second insulating layer ISL-32 may each independently have a thickness of from about 0.1 nm to about 10 nm.

[0108] The first insulating layer ISL-31 and the second insulating layer ISL-32 may contain the same or different materials. The first insulating layer ISL-31 and the second insulating layer ISL-32 may have the same or different thicknesses. The materials and thicknesses contained in each of the first insulating layer ISL-31 and the second insulating layer ISL-32 may be appropriately (or suitably) selected according to the type of quantum dots QD contained in the emission layer EML so as to achieve a suitable balance between hole injection properties and electron injection properties. For example, if the quantum dots QD contained in the emission layer EML have hole injection properties higher than electron injection properties, the thickness of the second insulating layer ISL-32 may be greater than the thickness of the first insulating layer ISL-31.

[0109] Reference Figure 7 According to an embodiment, the light-emitting diode EE-4 may include a first electrode EL1, a second electrode EL2 opposite to the first electrode EL1, and an emission layer EML disposed between the first electrode EL1 and the second electrode EL2, and may include an electron transport region ETR disposed between the first electrode EL1 and the emission layer EML, and a hole transport region HTR disposed between the emission layer EML and the second electrode EL2. An insulating layer ISL-4 may be disposed between the emission layer EML and the hole transport region HTR. The insulating layer ISL-4 may be disposed in contact with the emission layer EML. The light-emitting diode EE-4 may be a bottom-emitting light-emitting diode. That is, the light-emitting diode EE-4 may be a device that emits light in a direction from the second electrode EL2 to the first electrode EL1.

[0110] According to the type of quantum dots QD contained in the emission layer EML, the light-emitting diode EE-4 according to an embodiment may have hole injection properties higher than electron injection properties, but due to the insulating layer ISL-4 disposed between the hole transport layer HTL and the emission layer EML, the amounts of injected holes and electrons are controlled to achieve (realize) a balance, and thus, the light emission properties of the light-emitting diode EE-4 may be improved.

[0111] Reference Figure 8, the light-emitting diode EE-5 according to the embodiment may be a bottom-emitting light-emitting diode, and the insulating layer ISL-5 of the light-emitting diode EE-5 may be disposed between the electron transport region ETR and the emission layer EML. The insulating layer ISL-5 may be disposed in contact with the emission layer EML. The insulating layer ISL-5 may be disposed between the electron transport layer ETL and the emission layer EML, and may prevent or reduce the excessive injection of electrons from the electron transport layer ETL to the emission layer EML. More specifically, depending on the type of quantum dots QD included in the emission layer EML, the electron injection property may be higher than the hole injection property, but due to the insulating layer ISL-5 disposed between the electron transport layer ETL and the emission layer EML, the amount of injected electrons and the amount of holes may be controlled to achieve (realize) balance, and thus, the light emission property of the light-emitting diode EE-5 may be improved.

[0112] Reference Figure 9 , the insulating layer ISL-6 in the light-emitting diode EE-6 according to the embodiment may include multiple layers. The insulating layer ISL-6 may include a first insulating layer ISL-61 and a second insulating layer ISL-62. The first insulating layer ISL-61 may be disposed between the emission layer EML and the electron transport region ETR, and the second insulating layer ISL-62 may be disposed between the emission layer EML and the hole transport region HTR. Each of the first insulating layer ISL-61 and the second insulating layer ISL-62 may be disposed in contact with the emission layer EML. The materials and thicknesses included in the first insulating layer ISL-61 and the second insulating layer ISL-62 may be appropriately (or suitably) selected according to the type of quantum dots QD included in the emission layer EML in order to achieve (realize) a suitable balance between the hole injection property and the electron injection property. For example, if the quantum dots QD included in the emission layer EML have a hole injection property higher than the electron injection property, the thickness of the second insulating layer ISL-62 may be greater than the thickness of the first insulating layer ISL-61.

[0113] Figure 10 is a plan view of a display device DD according to an embodiment of the inventive concept. Figure 11 is a cross-sectional view of a display device DD according to an embodiment of the inventive concept. Figure 11 corresponds to Figure 10 a cross-sectional view taken along line II-II' in

[0114] The display device DD according to the embodiment includes a plurality of light-emitting diodes (EE-1, EE-2, and EE-3), and the light-emitting diode EE-1, the light-emitting diode EE-2, and the light-emitting diode EE-3 may include emission layers EML-B, EML-G, and EML-R respectively including quantum dots QD1, quantum dots QD2, and quantum dots QD3.

[0115] In addition, the display device DD of the embodiment may include a display panel DP including a plurality of light emitting diodes (EE-1, EE-2, and EE-3), and a light control layer PP disposed on the display panel DP. However, in some embodiments, the light control layer PP may be omitted from the display device DD.

[0116] The display panel DP may include a substrate BS, a circuit layer DP-CL disposed on the substrate BS, and a display device layer DP-OEL. The display device layer DP-OEL may include a pixel defining layer PDL, light emitting diodes EE-1, light emitting diodes EE-2, and light emitting diodes EE-3 (e.g., the light emitting diodes EE-1, light emitting diodes EE-2, and light emitting diodes EE-3 may be spaced apart from each other by the pixel defining layer PDL therebetween) disposed separately by the pixel defining layer PDL, and a encapsulation layer TFE disposed on the light emitting diodes EE-1, light emitting diodes EE-2, and light emitting diodes EE-3.

[0117] The substrate BS may be a member providing a substrate surface on which the display device layer DP-OEL is disposed. The substrate BS may be a glass substrate, a metal substrate, a plastic substrate, etc. However, embodiments of the inventive concept are not limited thereto, and the substrate BS may include (e.g., may be) an inorganic layer, an organic layer, or a composite material layer.

[0118] 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 a plurality of transistors. Each of the plurality of transistors may include a control electrode, an input electrode, and an output electrode. For example, the circuit layer DP-CL may include switching transistors and driving transistors for driving the light emitting diodes EE-1, light emitting diodes EE-2, and light emitting diodes EE-3 of the display device layer DP-OEL.

[0119] Each of the light emitting diodes EE-1, light emitting diodes EE-2, and light emitting diodes EE-3 may include a first electrode EL1, a hole transport region HTR, an emission layer EML-B, an emission layer EML-G, and an emission layer EML-R (respectively), an insulating layer ISL, an electron transport region ETR, and a second electrode EL2. The same explanations (descriptions) of the light emitting diode EE of the embodiments provided herein may be applied to the light emitting diodes EE-1, light emitting diodes EE-2, and light emitting diodes EE-3. For example, an insulating layer ISL may be disposed on the emission layers EML-B, EML-G, and EML-R of the light emitting diodes EE-1, light emitting diodes EE-2, and light emitting diodes EE-3. Figure 11An example embodiment is shown in which an insulating layer ISL is disposed between an emission layer EML-B, an emission layer EML-G, an emission layer EML-R, and an electron transport region ETR, but embodiments of the inventive concept are not limited thereto. The insulating layer ISL may be disposed between a hole transport region HTR and the emission layer EML-B, the emission layer EML-G, and the emission layer EML-R, respectively; or the insulating layer ISL may be disposed between the electron transport region ETR and the emission layer EML-B, the emission layer EML-G, and the emission layer EML-R, respectively, and may also be disposed between the hole transport region HTR and the emission layer EML-B, the emission layer EML-G, and the emission layer EML-R, respectively.

[0120] The encapsulation layer TFE may cover the light emitting diodes EE-1, EE-2, and EE-3. The encapsulation layer TFE may be directly disposed on the second electrode EL2. The encapsulation layer TFE may be a single layer (e.g., a single layer) or a laminated layer including multiple layers. The encapsulation layer TFE may be a thin film encapsulation layer. The encapsulation layer TFE protects the light emitting diodes EE-1, EE-2, and EE-3. The encapsulation layer TFE may cover the top surface of the second electrode EL2 disposed in the opening member OH and may fill the opening member OH.

[0121] Reference Figure 10 and Figure 11 , the display device DD may include a non-emission region NPXA and emission regions PXA-B, PXA-G, and PXA-R. Each of the emission regions PXA-B, PXA-G, and PXA-R may be a region that emits light generated from each of the light emitting diodes EE-1, EE-2, and EE-3. The emission regions PXA-B, PXA-G, and PXA-R may be spaced apart from each other in a plane (e.g., in a plane defined by a first direction DR1 and a second direction DR2).

[0122] According to the colors of the light generated in the light emitting diodes EE-1, EE-2, and EE-3, the emission regions PXA-B, PXA-G, and PXA-R may be divided into multiple groups. In the display device DD of the embodiment shown in Figure 10 and Figure 11 , three emission regions PXA-B, PXA-G, and PXA-R that emit blue light, green light, and red light, respectively, are shown as an embodiment. For example, the display device DD of the embodiment may include a blue emission region PXA-B, a green emission region PXA-G, and a red emission region PXA-R that are distinguishable from each other.

[0123] Multiple light-emitting diodes (EE-1, EE-2, and EE-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 diode EE-1 that emits blue light, a second light-emitting diode EE-2 that emits green light, and a third light-emitting diode EE-3 that emits red light. However, embodiments of the inventive concept are not limited thereto, and the first to third light-emitting diodes (EE-1, EE-2, and EE-3) may emit light in the same wavelength region, or at least one of them may emit light in different wavelength regions.

[0124] In one or more embodiments, the blue emission region PXA-B, the green emission region PXA-G, and the red emission region PXA-R of the display device DD may correspond to the first light-emitting diode EE-1, the second light-emitting diode EE-2, and the third light-emitting diode EE-3, respectively.

[0125] The first emission layer EML-B of the first light-emitting diode EE-1 may include a first quantum dot QD1. The first quantum dot QD1 may emit blue light as the first color light. The first light-emitting diode EE-1 may include a first host.

[0126] The second emission layer EML-G of the second light-emitting diode EE-2 and the third emission layer EML-R of the third light-emitting diode EE-3 may include a second quantum dot QD2 and a third quantum dot QD3, respectively. The second quantum dot QD2 and the third quantum dot QD3 may emit green light as the second color light and red light as the third color light, respectively. The second light-emitting diode EE-2 and the third light-emitting diode EE-3 may include a second host and a third host, respectively.

[0127] In Figure 11 one or more embodiments shown, the average diameters of the first to third quantum dots (QD1, QD2, and QD3) may be different from each other. For example, when compared with the second quantum dot QD2 of the second light-emitting diode EE-2 and the third quantum dot QD3 of the third light-emitting diode EE-3 that emit light in a relatively long wavelength region, the first quantum dot QD1 used in the first light-emitting diode EE-1 that emits light in a relatively short wavelength region may have a relatively smaller average diameter.

[0128] The relationship of the average diameters of the first to third quantum dots (QD1, QD2, and QD3) is not limited to the details defined above. That is, in Figure 11In the display device DD of the embodiment shown, the average diameters of the first quantum dot to the third quantum dot (QD1, QD2, and QD3) are shown to be different from each other. However, in one or more embodiments, the average diameters of the first quantum dot to the third quantum dot (QD1, QD2, and QD3) included in the light-emitting diodes EE-1, EE-2, and EE-3 may be similar. In some embodiments, the average diameters of two quantum dots selected from the first quantum dot to the third quantum dot (QD1, QD2, and QD3) may be similar, and the remaining one may be different.

[0129] In one or more embodiments, the first quantum dot to the third quantum dot (QD1, QD2, and QD3) included in the light-emitting diodes EE-1, EE-2, and EE-3 may be formed using different core materials from each other. In one or more embodiments, the first quantum dot to the third quantum dot (QD1, QD2, and QD3) may be formed using the same core material, or two selected from the first quantum dot to the third quantum dot (QD1, QD2, and QD3) may be formed using the same core material, and the remaining one may be formed using a different core material.

[0130] In the display device DD of the embodiment, as Figure 10 and Figure 11 shown, the areas of the emission region PXA-B, the emission region PXA-G, and the emission region PXA-R may be different from each other. In this case, the area of the emission region may be measured in a plane orthogonal to the third direction DR3 (for example, in a plane defined by the first direction DR1 and the second direction DR2).

[0131] Depending on the colors emitted from the emission layers EML-B, EML-G, and EML-R of the light-emitting diodes EE-1, EE-2, and EE-3, the emission regions PXA-B, PXA-G, and PXA-R may have different areas. For example, referring to Figure 10 and Figure 11, in the display device DD of the embodiment, the blue emission region PXA-B corresponding to the first light-emitting diode EE-1 that emits blue light may have the largest area, and the green emission region PXA-G corresponding to the second light-emitting diode EE-2 that generates green light may have the smallest area. However, the embodiments of the inventive concept are not limited thereto, and the emission regions PXA-B, PXA-G, and PXA-R may emit light other than blue light, green light, and red light, or the emission regions PXA-B, PXA-G, and PXA-R may have the same area. In some embodiments, the emission regions PXA-B, PXA-G, and PXA-R may be defined to have an area ratio different from Figure 10 shown in

[0132] Each of the emission regions PXA-B, PXA-G, and PXA-R may be a region separated by the pixel defining layer PDL. The non-emission region NPXA may be a region between adjacent emission regions PXA-B, PXA-G, and PXA-R and may correspond to the region of the pixel defining layer PDL. At the same time, each of the emission regions PXA-B, PXA-G, and PXA-R may correspond to a pixel in the present disclosure. The pixel defining layer PDL may separate (space apart) the light-emitting diodes EE-1, EE-2, and EE-3. The emission layers EML-B, EML-G, and EML-R of the light-emitting diodes EE-1, EE-2, and EE-3 may be separated in the opening member OH defined by the pixel defining layer PDL.

[0133] The pixel defining layer PDL may be formed of a polymer resin. For example, the pixel defining layer PDL may be formed by including an acrylate-based resin and / or a polyimide-based resin. In addition, the pixel defining layer PDL may be formed by further including an inorganic material other than the polymer resin. The pixel defining layer PDL may be formed by including a light absorption material and / or may be formed by including a black pigment and / or a black dye. The pixel defining layer PDL formed by including a black pigment and / or a black dye may be embodied as a black pixel defining layer. When forming the pixel defining layer PDL, carbon black may be used as the black pigment and / or the black dye, but the embodiments of the inventive concept are not limited thereto.

[0134] In one or more embodiments, the pixel defining layer PDL may be formed of an inorganic material. For example, it may be formed by including silicon nitride (SiN x ), silicon oxide (SiO x ), silicon oxynitride (SiO x N y(0.1 ≤ x ≤ 2.0)(0.1 ≤ y ≤ 2.0), etc. to form a pixel defining layer PDL. The pixel defining layer PDL can define an emission region PXA - B, an emission region PXA - G, and an emission region PXA - R. Through the pixel defining layer PDL, the emission region PXA - B, the emission region PXA - G, the emission region PXA - R, and the non - emission region NPXA can be separated (or arranged to be spaced apart from each other).

[0135] Reference Figure 10 , the blue emission region PXA - B and the red emission region PXA - R can be alternately arranged in the first direction DR1 to form a first group PXG1. The green emission region PXA - G can be arranged in the first direction DR1 to form a second group PXG2.

[0136] The first group PXG1 and the second group PXG2 can be provided in a spaced - apart manner in the second direction DR2. Each of the first group PXG1 and the second group PXG2 can be provided in multiple. The first group PXG1 and the second group PXG2 can be alternately arranged in the second direction DR2.

[0137] One green emission region PXA - G can be provided in a spaced - apart manner from one blue emission region PXA - B or one red emission region PXA - R in the fourth direction DR4. The fourth direction DR4 can be a direction (e.g., diagonal) between the first direction DR1 and the second direction DR2.

[0138] Figure 10 The arrangement structure of the emission region PXA - B, the emission region PXA - G, and the emission region PXA - R shown in can have a corrugated tile structure. However, the arrangement structure of the emission region PXA - B, the emission region PXA - G, and the emission region PXA - R in the display device DD according to the present embodiment is not limited to Figure 10 the arrangement structure shown in. For example, in one or more embodiments, the emission region PXA - B, the emission region PXA - G, and the emission region PXA - R can have a stripe structure, in which the blue emission region PXA - B, the green emission region PXA - G, and the red emission region PXA - R can be alternately arranged along the first direction DR1.

[0139] Reference Figure 2 and Figure 11 , the display device DD of the embodiment further includes a light control layer PP. In the display device DD, the light control layer PP can block or reduce the external light incident on the display panel DP from the outside of the display device DD. The light control layer PP can block or reduce a part of the external light. The light control layer PP can have an anti - reflection function, through which the reflection of the external light can be minimized or reduced.

[0140] In Figure 11In one or more embodiments shown, the light control layer PP may include a color filter layer CFL. In the display device DD of the embodiment, the light control layer PP may include a substrate layer BL and a color filter layer CFL.

[0141] The substrate layer BL may be a member providing a substrate surface on which the color filter layer CFL and the like are disposed. The substrate layer BL may be a glass substrate, a metal substrate, a plastic substrate, or the like. However, embodiments of the inventive concept are not limited thereto, and the substrate layer BL may be an inorganic layer, an organic layer, or a composite material layer.

[0142] The color filter layer CFL may include a light blocking member BM and a color filter member CF. The color filter member CF may include a plurality of color filters (CF-B, CF-G, and CF-R). That is, the color filter layer CFL may include a first color filter CF-B that transmits first color light, a second color filter CF-G that transmits second color light, and a third color filter CF-R that transmits third color light. For example, the first color filter CF-B may be a blue color filter, the second color filter CF-G may be a green color filter, and the third color filter CF-R may be a red color filter.

[0143] Each of the color filters CF-B, CF-G, and CF-R may include a polymer photosensitive resin and a pigment or a dye. The first color filter CF-B may include a blue pigment or dye, the second color filter CF-G may include a green pigment or dye, and the third color filter CF-R may include a red pigment or dye.

[0144] Each of the color filters CF-B, CF-G, and CF-R may include a light emitter. Each of the color filters CF-B, CF-G, and CF-R may include quantum dots. The quantum dots included in the first color filter CF-B, the second color filter CF-G, and the third color filter CF-R may be different from each other. The quantum dots included in the first color filter CF-B, the second color filter CF-G, and the third color filter CF-R may have different core materials and / or the average diameters of the included cores may be different from each other.

[0145] However, embodiments of the inventive concept are not limited thereto, and the first color filter CF-B may not include a pigment, a dye, or a light emitter. For example, the first color filter CF-B may include a polymer photosensitive resin and may not include a pigment, a dye, and / or a light emitter. The first color filter CF-B may be transparent. The first color filter CF-B may be formed using a transparent photosensitive resin.

[0146] The light blocking member BM may be a black matrix. The light blocking member BM may be formed by including an organic light blocking material and / or an inorganic light blocking material (including a black pigment and / or a black dye). The light blocking member BM may prevent or reduce light leakage and demarcate boundaries between adjacent color filters CF-B, CF-G, and CF-R.

[0147] The color filter layer CFL may further include a buffer layer BFL. For example, the buffer layer BFL may be a protective layer that protects the color filters CF-B, CF-G, and CF-R. The buffer layer BFL may include an inorganic layer containing at least one inorganic material selected from silicon nitride, silicon oxide, and silicon oxynitride. The buffer layer BFL may include an organic layer that may help flatten the bottom surface of the color filter layer CFL. The buffer layer BFL may include, for example, an organic layer containing an acrylate-based organic material. The buffer layer BFL may be formed as a single layer or multiple layers.

[0148] In Figure 11 one or more of the embodiments shown, the first color filter CF-B of the color filter layer CFL is shown overlapping the second color filter CF-G and the third color filter CF-R, but the embodiments of the inventive concept are not limited thereto. For example, the first to third color filters (CF-B, CF-G, and CF-R) may be separated by the light blocking member BM and not overlap each other. In one or more embodiments, the first to third color filters (CF-B, CF-G, and CF-R) may be arranged to respectively correspond to a blue emission region PXA-B, a green emission region PXA-G, and a red emission region PXA-R.

[0149] Figure 12 is a cross-sectional view showing a display device DD-1 according to an embodiment of the inventive concept. In explaining the display device DD-1 according to the embodiment shown in Figure 12 the same reference symbols are assigned to the elements described above with reference to Figure 11 and the description provided above will not be repeated.

[0150] According to Figure 12 the embodiment shown in, the display device DD-1 may include a display panel DP including a plurality of light emitting diodes (EE-1, EE-2, and EE-3), and a light control layer PP-1. The same explanations provided above in connection with Figure 11 may be applied to the display panel DP included in Figure 12 the display device DD-1 and the light emitting diodes EE-1, EE-2, and EE-3.

[0151] As Figure 12The display device DD-1 of the embodiment shown in is different from the display device DD shown in terms of the light control layer and Figure 11 The display device DD shown in. As Figure 12 The light control layer PP-1 included in the display device DD-1 of the embodiment shown in may include a polarization layer POL.

[0152] In one or more embodiments, the light control layer PP-1 may include a polarization layer POL and a substrate layer BL that supports the polarization layer POL.

[0153] The substrate layer BL may be a member that provides a substrate surface on which the polarization layer POL is disposed. The substrate layer BL may be a glass substrate, a metal substrate, a plastic substrate, etc. However, the embodiments of the inventive concept are not limited thereto, and the substrate layer BL may be an inorganic layer, an organic layer, or a composite material layer.

[0154] The polarization layer POL may block or reduce external light incident on the display panel DP. For example, the polarization layer POL may block or reduce a part of the external light.

[0155] In addition, the polarization layer POL may reduce the reflected external light at the display panel DP. For example, in an embodiment where incident light from the outside of the display device DD-1 is incident on the display panel DP and then reflected, the polarization layer POL may perform a function of blocking (e.g., may block or reduce) the reflected light. The polarization layer POL may be a circular polarizer having an anti-reflection (or reduction) function and / or the polarization layer POL may include a λ / 4 phase retarder from a linear polarizer.

[0156] In Figure 12 The polarization layer POL is shown as being disposed on and exposed from the substrate layer BL, but the embodiments of the inventive concept are not limited thereto. For example, the polarization layer POL may be disposed under the substrate layer BL.

[0157] One or more display devices of the present embodiment may include an insulating layer above and / or below an emission layer containing quantum dots, and the insulating layer may maintain (achieve and / or sustain) a balance between the hole injection property and the electron injection property of the material for the emission layer. Accordingly, the display device may exhibit improved lifetime characteristics and emission efficiency properties.

[0158] Hereinafter, a method for manufacturing a light-emitting diode according to one or more embodiments of the inventive concept will be explained with reference to the accompanying drawings.

[0159] Figure 13 is a flowchart of a method for manufacturing a light-emitting diode according to an embodiment of the inventive concept. Figures 14A to 14EIt is a cross-sectional view showing operations of a method for sequentially manufacturing a light-emitting diode according to an embodiment of the inventive concept.

[0160] Reference Figure 13 , a method for manufacturing a light-emitting diode according to an embodiment of the inventive concept includes a step (operation) (S100) of preparing a first electrode, a step (operation) (S200) of forming an emission layer on the first electrode, a step (operation) (S300) of forming an insulating layer on the emission layer, and a step (operation) (S400) of forming a second electrode on the insulating layer.

[0161] Reference Figure 13 and Figure 14A , a method for manufacturing a light-emitting diode according to an embodiment of the inventive concept includes a step of forming an emission layer EML on a first electrode EL1 after the step of preparing the first electrode EL1 (S200). In a method for manufacturing a light-emitting diode according to one or more embodiments, a step of forming a plurality of organic layers may be further included before the step of forming the emission layer EML. In one or more embodiments, before forming the emission layer EML, and after sequentially forming a hole injection layer HIL and a hole transport layer HTL, the emission layer EML may be formed on the hole transport layer HTL. One or more suitable methods (e.g., vacuum deposition method, spin coating method, casting method, Langmuir-Blodgett (LB) method, inkjet printing method, laser printing method, and / or laser-induced thermal imaging (LITI) method) may be used to form the hole injection layer HIL, the hole transport layer HTL, and the emission layer EML.

[0162] The emission layer EML includes quantum dots QD. The emission layer EML may be formed by dispersing a plurality of quantum dots QD in a material for a matrix member HS, and then applying and drying it.

[0163] Refer together to Figure 13 , Figure 14A and Figure 14B , an inorganic material IOL is deposited on the emission layer EML to form an inorganic insulating layer ISL-IOL1. The inorganic insulating layer ISL-IOL1 may be formed by depositing the inorganic material IOL via an atomic layer deposition (ALD) method. The inorganic material IOL may include at least one selected from SiN x , SiO x , Al2O3, TiO x and ZrO x (0.1 ≤ x ≤ 2.0).

[0164] Refer together to Figure 13 , Figure 14B and Figure 14C, an organic material OL is deposited on the inorganic insulating layer ISL-IOL1 to form an organic insulating layer ISL-OL1. The organic insulating layer ISL-OL1 can be formed by depositing the organic material OL via a chemical vapor deposition (CVD) method. The organic material OL can include at least one selected from n-hexane, furan, and hexamethyldisiloxane.

[0165] Referring together Figure 13 , Figure 14C and Figure 14D , after forming the organic insulating layer ISL-OL1, an inorganic material IOL can be deposited again to form a second inorganic insulating layer ISL-IOL2. The second inorganic insulating layer ISL-IOL2 can be formed by depositing the inorganic material IOL via an atomic layer deposition (ALD) method.

[0166] As Figures 14A to 14D shown, a method for manufacturing a light-emitting diode according to one or more embodiments of the inventive concept includes a step of forming an insulating layer ISL' by depositing an inorganic material IOL on an emission layer EML. The step of forming the insulating layer ISL' can include a step of forming an inorganic insulating layer ISL-IOL1 and an inorganic insulating layer ISL-IOL2 by depositing the inorganic material IOL, and a step of forming an organic insulating layer ISL-OL1 by depositing the organic material OL. The step of forming the inorganic insulating layer ISL-IOL1 and the inorganic insulating layer ISL-IOL2 by depositing the inorganic material IOL, and the step of forming the organic insulating layer ISL-OL1 by depositing the organic material OL can be performed alternately and multiple times. In Figures 14A to 14D , a case where the step of forming the inorganic insulating layer ISL-IOL1 and the inorganic insulating layer ISL-IOL2 is performed twice and the step of forming the organic insulating layer ISL-OL1 is performed once is shown as an example, but the embodiments of the inventive concept are not limited thereto, and the step of forming the inorganic insulating layer ISL-IOL1 and the inorganic insulating layer ISL-IOL2 and the step of forming the organic insulating layer ISL-OL1 can be performed two or more times, respectively.

[0167] In a method for manufacturing a light-emitting diode according to one or more embodiments of the inventive concept, a first nozzle NZ1 for ejecting an inorganic material IOL and a second nozzle NZ2 for ejecting an organic material OL may be included in the same chamber, and a process of ejecting the inorganic material IOL and a process of ejecting the organic material OL may be alternately performed in the same chamber. In one or more embodiments, the first nozzle NZ1 for ejecting the inorganic material IOL and the second nozzle NZ2 for ejecting the organic material OL may be disposed adjacent to each other in the same chamber, and when a platform on which the light-emitting diode is located reciprocally moves during a deposition step, the inorganic material IOL and the organic material OL may be alternately ejected to alternately form an inorganic insulating layer ISL-IOL1 and an inorganic insulating layer ISL-IOL2, and an organic insulating layer ISL-OL1.

[0168] Reference Figure 13 and Figure 14E , a method for manufacturing a light-emitting diode according to an embodiment of the inventive concept includes a step of forming a second electrode EL2 on an insulating layer ISL'. In a method for manufacturing a light-emitting diode according to an embodiment, a step of forming a plurality of organic layers may be further included before the step of forming the second electrode EL2. In one or more embodiments, before forming the second electrode EL2 and after sequentially forming an electron transport layer ETL and an electron injection layer EIL, the second electrode EL2 may be formed on the electron injection layer EIL. The electron transport layer ETL and the electron injection layer EIL may each independently be formed using one or more suitable methods (e.g., a vacuum deposition method, a spin coating method, a casting method, a Langmuir-Blodgett (LB) method, an inkjet printing method, a laser printing method, and / or a laser-induced thermal imaging (LITI) method).

[0169] According to one or more embodiments of the inventive concept, an insulating layer is adjacent to an emission layer including quantum dots, and charge balance of the emission layer may be improved, and thereby, the lifespan and emission efficiency of a light-emitting diode and a display device including the light-emitting diode may be improved.

[0170] As used herein, the terms "use", "using", and "used" may be considered to be synonymous with the terms "utilize", "utilizing", and "utilized", respectively.

[0171] Furthermore, the terms "substantially", "about", and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for inherent deviations in measured or calculated values that would be recognized by a person of ordinary skill in the art.

[0172] In addition, any numerical range recited herein is intended to include all sub-ranges of the same numerical precision falling within the recited range. For example, a range of "1.0 to 10.0" is intended to include all sub-ranges between (and including the end values) the recited minimum value of 1.0 and the recited maximum value of 10.0, that is, having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limitation recited herein is intended to include all lower numerical limitations subsumed therein, and any minimum numerical limitation recited in this specification is intended to include all higher numerical limitations subsumed therein. Accordingly, the applicant reserves the right to modify this specification (including the claims) to expressly recite any sub-ranges that fall within the ranges expressly recited herein.

[0173] Although exemplary embodiments of the inventive concept have been described, it is to be understood that various changes and modifications can be made by those of ordinary skill in the art within the spirit and scope of the inventive concept described in the appended claims and their equivalents.

[0174] Accordingly, the technical scope of the inventive concept will be determined by the appended claims and their equivalents and should not be limited or restricted by the foregoing detailed description.

Claims

1. A light-emitting diode, comprising: A first electrode; A second electrode opposite to the first electrode; An emission layer between the first electrode and the second electrode, the emission layer comprising quantum dots; A first charge transfer layer between the first electrode and the emission layer; A second charge transfer layer between the second electrode and the emission layer; And An insulating layer between the first charge transfer layer and the emission layer and / or between the second charge transfer layer and the emission layer, Wherein the insulating layer comprises an inorganic insulating layer containing an inorganic material and an organic insulating layer containing an organic material, Wherein the organic material comprises at least one selected from n-hexane, furan, and hexamethyldisiloxane.

2. The light-emitting diode according to claim 1, wherein the insulating layer comprises at least one selected from SiN x , SiO x , Al2O3, TiO x , and ZrO x , where 0.1 ≤ x ≤ 2.

0.

3. The light-emitting diode according to claim 1, wherein the insulating layer comprises a plurality of inorganic insulating layers containing the inorganic material and a plurality of organic insulating layers containing the organic material, and The plurality of inorganic insulating layers and the plurality of organic insulating layers are alternating in the insulating layer.

4. The light-emitting diode according to claim 1, wherein The first charge transfer layer comprises: A hole injection layer adjacent to the first electrode; And A hole transport layer between the hole injection layer and the emission layer, and the second charge transfer layer comprises: An electron injection layer adjacent to the second electrode; And An electron transport layer between the electron injection layer and the emission layer.

5. The light-emitting diode according to claim 4, wherein the quantum dots comprise a cadmium-based material, and The insulating layer is between the electron transport layer and the emission layer.

6. The light-emitting diode according to claim 1, wherein the insulating layer contacts the emission layer.

7. The light-emitting diode according to claim 1, wherein the thickness of the insulating layer is 0.1 nm to 10 nm.

8. A display device, comprising a plurality of light-emitting diodes, wherein each light-emitting diode of the plurality of light-emitting diodes comprises: A first electrode; A second electrode opposite to the first electrode; An emission layer between the first electrode and the second electrode, the emission layer comprising quantum dots; A first charge transfer layer between the first electrode and the emission layer; A second charge transfer layer between the second electrode and the emission layer; And An insulating layer between the first charge transfer layer and the emission layer and / or between the second charge transfer layer and the emission layer, Wherein the insulating layer comprises an inorganic insulating layer containing an inorganic material and an organic insulating layer containing an organic material, Wherein the organic material comprises at least one selected from n-hexane, furan, and hexamethyldisiloxane.

9. A method for manufacturing a light-emitting diode, the method comprising: Forming an emission layer containing quantum dots on a first electrode; Forming an insulating layer on the emission layer; And Forming a second electrode on the insulating layer, Wherein the forming of the insulating layer comprises forming an inorganic insulating layer by depositing an inorganic material and forming an organic insulating layer by depositing an organic material, Wherein the organic material comprises at least one selected from n-hexane, furan, and hexamethyldisiloxane.

Images