Light-emitting element, ink composition, and method for manufacturing light-emitting element

Abstract

Embodiments provide a light-emitting element, an ink composition, and a method for manufacturing the light-emitting element. The light emitting element includes: a first electrode; a second electrode disposed on the first electrode; an emission layer disposed between the first electrode and the second electrode; and a hole transport region disposed between the first electrode and the emission layer, in which the hole transport region includes nanoparticles, and each of the nanoparticles includes a core represented by Formula 1 as described in the specification, [Formula 1] Ni1-xMxO.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2024-0018287 filed on February 6, 2024, in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a light-emitting element, an ink composition, and a method for manufacturing a light-emitting element. Background Art

[0004] Various display devices have been developed for use in multimedia devices such as televisions, mobile phones, tablet computers, navigation units, and game consoles. Such display devices use so-called self-luminous display elements that achieve display by emitting light from a light-emitting material including an organic compound.

[0005] In order to enhance color reproducibility of a display device, light emitting elements using quantum dots as a light emitting material have been developed, and there is a demand for improving the light emitting efficiency and lifespan of the light emitting elements using quantum dots.

[0006] It will be understood that this background technology section is intended, in part, to provide a useful background for understanding the technology. However, this background technology section may also include ideas, concepts, or cognitions that were not already known or understood as a part by those skilled in the relevant art before the corresponding effective filing date of the subject matter disclosed herein. Summary of the Invention

[0007] The present disclosure provides a light emitting element having improved luminous efficiency and service life.

[0008] The present disclosure also provides an ink composition capable of improving the light-emitting characteristics and service life of a light-emitting element.

[0009] The present disclosure also provides a method for manufacturing a light emitting element with improved process reliability.

[0010] According to an embodiment, a light-emitting element may include: a first electrode; a second electrode disposed on the first electrode; an emission layer disposed between the first electrode and the second electrode; and a hole transport region disposed between the first electrode and the emission layer, the hole transport region including a plurality of nanoparticles, wherein the plurality of nanoparticles may each include a core represented by Formula 1:

[0011] [Formula 1]

[0012] Ni 1-x M xO.

[0013] In Formula 1, M may be Zn, Sn, Ti, Cu, Mg, or Cr; and x may satisfy 0<x<1.

[0014] In an embodiment, in Formula 1, x may satisfy 0.01≤x<0.03.

[0015] In an embodiment, in Formula 1, M may be Zn.

[0016] In an embodiment, the plurality of nanoparticles may each further include a ligand bonded to a surface of the core.

[0017] In an embodiment, the ligand may include at least one of 2-(2-methoxyethoxy)ethylamine, 2-(2-methoxyethoxy)acetic acid, and 2-(2-methoxyethoxy)ethanethiol.

[0018] In an embodiment, the amount of the ligand may be in a range of about 10 wt % to about 30 wt % relative to 100 wt % of the total weight of the nanoparticles.

[0019] In an embodiment, the hole transport region may further include an additive represented by Formula 2:

[0020]

[0021] In Formula 2, R1 to R3 may each independently be a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms; R4 may be a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms, ... an unsubstituted cycloalkylene group having 3 to 30 ring carbon atoms, a substituted or unsubstituted arylene group having 6 to 60 ring carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 60 ring carbon atoms; a1 to a3 may each independently be 0 or 1, with the proviso that at least one of a1 to a3 may be 1; and F1 may be a substituted or unsubstituted (meth)acrylate group, a substituted or unsubstituted epoxy group, or a substituted or unsubstituted amine group.

[0022] In an embodiment, the additive may be represented by one of Formulas 3-1 to 3-5:

[0023]

[0024]

[0025] In an embodiment, the emissive layer may include quantum dots.

[0026] In an embodiment, the light emitting element may further include: an electron transport region disposed between the second electrode and the emission layer, wherein the electron transport region may include a metal oxide.

[0027] In an embodiment, the metal oxide may include at least one of ZnO, ZnSnO, ZnMgO, SnO 2 , and ZnGaO.

[0028] According to an embodiment, an ink composition may include a plurality of nanoparticles, wherein the plurality of nanoparticles may each include a core represented by Formula 1:

[0029] [Formula 1]

[0030] Ni 1-x M x O.

[0031] In Formula 1, M may be Zn, Sn, Ti, Cu, Mg, or Cr; and x may satisfy 0.01≤x<0.03.

[0032] In an embodiment, in Formula 1, M may be Zn.

[0033] In an embodiment, the plurality of nanoparticles may each further include a ligand bonded to a surface of the core.

[0034] In an embodiment, the ligand may include at least one of 2-(2-methoxyethoxy)ethylamine, 2-(2-methoxyethoxy)acetic acid, and 2-(2-methoxyethoxy)ethanethiol.

[0035] In an embodiment, the amount of the ligand may be in a range of about 10 wt % to about 30 wt % relative to 100 wt % of the total weight of the nanoparticles.

[0036] In an embodiment, the ink composition may further include an additive represented by Formula 2:

[0037]

[0038] In Formula 2, R1 to R3 may each independently be a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms; R4 may be a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms, ... an unsubstituted cycloalkylene group having 3 to 30 ring carbon atoms, a substituted or unsubstituted arylene group having 6 to 60 ring carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 60 ring carbon atoms; a1 to a3 may each independently be 0 or 1, with the proviso that at least one of a1 to a3 may be 1; and F1 may be a substituted or unsubstituted (meth)acrylate group, a substituted or unsubstituted epoxy group, or a substituted or unsubstituted amine group.

[0039] According to an embodiment, a method for manufacturing a light-emitting element may include: forming a hole transport region on a first electrode; forming an emission layer on the hole transport region; forming an electron transport region on the emission layer; and forming a second electrode on the electron transport region, wherein the forming of the hole transport region may include: preparing an ink composition including a plurality of nanoparticles; providing the ink composition on the first electrode to form a preliminary hole transport region; and heat-treating the preliminary hole transport region; and the plurality of nanoparticles may each include a core represented by Formula 1:

[0040] [Formula 1]

[0041] Ni 1-x M x O.

[0042] In Formula 1, M may be Zn, Sn, Ti, Cu, Mg, or Cr; and x may satisfy 0<x<1.

[0043] In an embodiment, the forming of the emission layer may include: providing a quantum dot composition including quantum dots on the hole transport region to form a preliminary emission layer; and heat-treating the preliminary emission layer.

[0044] In an embodiment, the forming of the electron transport region may include: providing an electron transport composition including a metal oxide on the emission layer to form a preliminary electron transport region; and heat-treating the preliminary electron transport region.

[0045] It will be understood that the above embodiments have been described in a general and illustrative sense only and not for purposes of limitation, and that the present disclosure is not limited to the embodiments described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated into and constitute a part of this specification. The accompanying drawings illustrate embodiments of the present disclosure and the principles of the present disclosure. The above and other aspects and features of the present disclosure will become more apparent by describing in detail embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0047] Figure 1 is a schematic perspective view of a display device according to an embodiment;

[0048] Figure 2 is with Figure 1 A schematic cross-sectional view of a display device according to an embodiment corresponding to a virtual line II';

[0049] Figure 3 is a schematic plan view of a display device according to an embodiment;

[0050] Figure 4 is a schematic cross-sectional view of a display device according to an embodiment;

[0051] Figure 5A and Figure 5B Each is a schematic cross-sectional view of a light emitting element according to an embodiment;

[0052] Figure 6 is a flow chart of a method for manufacturing a light emitting element according to an embodiment;

[0053] Figure 7 is a flow chart of steps for forming a hole transport region according to an embodiment;

[0054] Figure 8 is a schematic cross-sectional view of an ink composition according to an embodiment; and

[0055] Figures 9A to 9C Each is a schematic cross-sectional view of a method step for manufacturing a light-emitting element according to an embodiment. DETAILED DESCRIPTION

[0056] The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments are shown. However, the present disclosure may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0057] In the drawings, the size, thickness, ratio and dimensions of elements may be exaggerated for ease of description and for clarity. The same reference numerals and / or the same reference characters refer to the same elements throughout.

[0058] In the description, it will be understood that when an element (or region, layer, component, etc.) is referred to as being "on," "connected to," or "coupled to" another element, the element may be directly on, directly connected to, or directly coupled to the other element, or one or more intervening elements may be present between the element and the other element. In a similar sense, when an element (or region, layer, component, etc.) is described as "overlying" another element, the element may directly overly the other element, or one or more intervening elements may be present between the element and the other element.

[0059] In the description, when an element is “directly on,” “directly connected to,” or “directly coupled to” another element, there are no intervening elements present. For example, “directly on” may mean that two layers or elements are disposed without an additional element, such as an adhesive element, between the two layers or elements.

[0060] As used herein, expressions used in the singular such as “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0061] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. For example, "A and / or B" may be understood to mean "A, B, or A and B." The terms "and" and "or" may be used in a conjunction or disjunction sense and may be understood to be equivalent to "and / or."

[0062] In the specification and claims, for purposes of its meaning and description, the term "at least one of" is intended to include the meaning of "at least one selected from the group consisting of." For example, "at least one of A, B, and C" may be understood to mean only A, only B, only C, or any combination of two or more of A, B, and C (such as ABC, AB, BC, or AC). When preceding or following a list of elements, the term "at least one of" modifies the entire list of elements and does not modify the individual elements of the list.

[0063] It will be understood that, although the terms first, second, etc. can 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 element. Therefore, without departing from the teachings of the present disclosure, the first element can be named as the second element. Similarly, without departing from the scope of the present disclosure, the second element can be named as the first element.

[0064] For ease of description, spatially relative terms such as "below," "under," "down," "above," or "upper" may be used herein to describe the relationship between one element or component and another element or component as shown in the accompanying drawings. It will be understood that in addition to the orientations depicted in the accompanying drawings, spatially relative terms are intended to cover different orientations of the device in use or operation. For example, where the device shown in the accompanying drawings is turned over, a device positioned "below" or "beneath" another device may be placed "above" another device. Thus, the illustrative term "below" may include both lower and upper positions. The device may also be oriented in other directions, and therefore spatially relative terms may be interpreted differently depending on the orientation.

[0065] As used herein, the terms "about" or "approximately" include the stated value and mean within an acceptable range of deviation from the recited value as determined by one of ordinary skill in the art, taking into account the measurements in question and errors associated with the measurement of the recited quantities (e.g., limitations of the measurement system). For example, "about" can mean within one or more standard deviations, or within ±20%, ±10%, or ±5% of the stated value.

[0066] It should be understood that the terms “comprises, comprising,” “includes, including,” “have, having,” and “contains, containing,” etc. are intended to illustrate the presence of the stated features, integers, steps, operations, elements, components, or combinations thereof in the present disclosure, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

[0067] Unless otherwise defined or implied herein, all terms (including technical and scientific terms) used have the same meaning as commonly understood by those skilled in the art to which the present disclosure belongs. It will also be understood that, unless expressly defined in the specification, terms (such as those defined in general dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense.

[0068] In the specification, the term "substituted or unsubstituted" can describe a group that is substituted or unsubstituted by at least one substituent selected from the group consisting of a deuterium atom, a halogen atom, a cyano group, a nitro group, an amino group, an amine group, a silyl group, an oxy group, a sulfenyl group, a sulfinyl group, a sulfonyl group, a carbonyl group, a boron group, a phosphine oxide group, a phosphine sulfide group, an alkyl group, an alkenyl group, an alkynyl group, a hydrocarbon ring group, an aryl group, and a heterocyclic group. Each of the substituents listed above can itself be substituted or unsubstituted. For example, a biphenyl group can be interpreted as an aryl group, or a biphenyl group can be interpreted as a phenyl group substituted by a phenyl group.

[0069] In the specification, examples of the halogen atom may include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0070] In the specification, the alkyl group may be linear or branched. The number of carbon atoms in the alkyl group may be 1 to 50, 1 to 30, 1 to 20, 1 to 10, or 1 to 6. Examples of the alkyl group may include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, 2-ethylbutyl, 3,3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, 1-methylpentyl, 3-methylpentyl, 2-ethylpentyl, 4-methyl-2-pentyl, n-hexyl, 1-methylhexyl, 2-ethylhexyl, 2-butylhexyl, n-heptyl, 1-methylheptyl, 2,2-dimethylheptyl, 2-ethylheptyl, 2-butylheptyl, n-octyl, tert-octyl, 2-ethyloctyl, 2-butyloctyl, 2-hexyloctyl, 3,7-dimethyloctyl, n-nonyl, n-decyl, adamantyl, 2-ethyldecyl, 2-butyldecyl, 2-hexyldecyl, 2-octyldecyl, n-decyl The following examples include monodecyl, n-dodecyl, 2-ethyldodecyl, 2-butyldodecyl, 2-hexyldodecyl, 2-octyldodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, 2-ethylhexadecyl, 2-butylhexadecyl, 2-hexylhexadecyl, 2-octylhexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, 2-ethyleicosyl, 2-butyleicosyl, 2-hexyleicosyl, 2-octyleicosyl, n-heneicosyl, n-docosyl, n-tricosyl, n-tetracosyl, n-pentacosyl, n-hexacosyl, n-heptacosyl, n-octacosyl, n-nonacosyl, n-triacontyl, etc., but the embodiments are not limited thereto.

[0071] In the specification, the cycloalkyl group may be a cyclic alkyl group. The number of carbon atoms in the cycloalkyl group may be 3 to 50, 3 to 30, 3 to 20, or 3 to 10. Examples of cycloalkyl groups may include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, norbornyl, 1-adamantyl, 2-adamantyl, isobornyl, bicycloheptyl, etc., but embodiments are not limited thereto.

[0072] In the specification, an alkenyl group may be a hydrocarbon group including at least one carbon-carbon double bond in the middle or at the end of an alkyl group having 2 or more carbon atoms. An alkenyl group may be linear or branched. The number of carbon atoms in the alkenyl group is not particularly limited and may be 2 to 30, 2 to 20, or 2 to 10. Examples of alkenyl groups may include vinyl, 1-butenyl, 1-pentenyl, 1,3-butadienyl, styryl, styrylvinyl, etc., but embodiments are not limited thereto.

[0073] In the specification, an aryl group may be any functional group or substituent derived from an aromatic hydrocarbon ring. An aryl group may be monocyclic or polycyclic. The number of ring carbon atoms in the aryl group may be 6 to 60, 6 to 50, 6 to 40, 6 to 30, 6 to 20, or 6 to 15. Examples of aryl groups may include phenyl, naphthyl, fluorenyl, anthracenyl, phenanthrenyl, biphenyl, terphenyl, quaterphenyl, pentyl, hexyl, triphenylenyl, pyrenyl, benzofluoranthenyl, However, the embodiment is not limited thereto.

[0074] In the specification, the heteroaryl group may include at least one of B, O, N, P, Si and S as a heteroatom. If the heteroaryl group includes two or more heteroatoms, the two or more heteroatoms may be the same as or different from each other. The heteroaryl group may be monocyclic or polycyclic. The number of ring carbon atoms in the heteroaryl group may be 2 to 60, 2 to 50, 2 to 40, 2 to 30, 2 to 20 or 2 to 10. Examples of heteroaryl groups may include thienyl, furyl, pyrrolyl, imidazolyl, pyridyl, bipyridyl, pyrimidyl, triazinyl, triazolyl, acridinyl, pyridazinyl, pyrazinyl, quinolyl, quinazolinyl, quinoxalinyl, phenoxazinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolyl, indolyl, carbazolyl, N-arylcarbazolyl, N-heteroarylcarbazolyl, N-alkylcarbazolyl, benzoxazolyl, benzimidazolyl, benzothiazolyl, benzocarbazolyl, benzothienyl, dibenzothienyl, thienothiphenyl, benzofuranyl, phenanthrolinyl, thiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, thiadiazolyl, phenothiazinyl, dibenzothiorol, dibenzofuranyl, and the like, but embodiments are not limited thereto.

[0075] In the specification, the above description of the aryl group may be applied to the arylene group except that the arylene group is a divalent group. In the specification, the above description of the heteroaryl group may be applied to the heteroarylene group except that the heteroarylene group is a divalent group.

[0076] In the specification, the silyl group may be an alkylsilyl group or an arylsilyl group. Examples of the silyl group may include trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, vinyldimethylsilyl, propyldimethylsilyl, triphenylsilyl, diphenylsilyl, phenylsilyl, etc., but the embodiment is not limited thereto.

[0077] In the specification, the number of carbon atoms in the amino group is not particularly limited and may be 1 to 30. The amino group may be an alkylamino group or an arylamino group. Examples of the amino group may include methylamino, dimethylamino, anilino, diphenylamino, naphthylamino, 9-methylanthrylamino, etc., but the embodiment is not limited thereto.

[0078] In the specification, the alkyl group of the alkylaryl group, the alkylsilyl group, or the alkylamine group may be the same as exemplified for the alkyl group described above.

[0079] In the specification, the aryl group in the arylsilyl group or the arylamine group may be the same as exemplified as the aryl group described above.

[0080] In the specification, the term "(meth)acrylate" may be interpreted as meaning "acrylate or methacrylate".

[0081] In the specification, the symbol -* represents a bond to an adjacent atom in the corresponding formula or moiety.

[0082] Hereinafter, an ink composition, a light emitting element formed of the ink composition, and a method for manufacturing the light emitting element according to embodiments will be described with reference to the accompanying drawings.

[0083] Figure 1 is a schematic perspective view of a display device according to an embodiment. Figure 2 is with Figure 1 A virtual line II' corresponds to a schematic cross-sectional view of the display device according to the embodiment.

[0084] Reference Figure 1According to an embodiment, the display device DD can be activated by an electrical signal. For example, the display device DD can be a large device such as a television, a monitor, or an outdoor billboard. The display device DD can be a small or medium-sized device such as a personal computer (e.g., a laptop computer, a tablet computer), a personal digital assistant, a car navigation system, a game console, a smartphone, or a camera. These devices are presented only as examples, and thus the display device DD can be adopted in other electronic devices within the scope of the embodiments.

[0085] The display device DD may display an image (or video) through a display surface DD-IS. The display surface DD-IS may be parallel to a plane defined by the first direction DR1 and the second direction DR2. The display surface DD-IS may include a display area DA and a non-display area NDA.

[0086] The pixels PX may be disposed in the display area DA, and the pixels PX may not be disposed in the non-display area NDA. The non-display area NDA may be defined by the edge of the display surface DD-IS. The non-display area NDA may surround (e.g., completely surround) the display area DA. However, embodiments are not limited thereto, and the non-display area NDA may be omitted, or the non-display area NDA may be disposed only on one side of the display area DA.

[0087] Figure 1 The display surface DD-IS of the display device DD is shown to be flat, but the embodiment is not limited thereto. The display device DD may have a curved display surface or a three-dimensional display surface. The three-dimensional display surface may include multiple display areas extending in different directions.

[0088] Figure 1 and the remaining drawings show a first direction DR1, a second direction DR2, and a third direction DR3, and the directions indicated by the first direction DR1, the second direction DR2, and the third direction DR3 described in this specification are relative concepts and can be converted into other directions. In the specification, the first direction DR1 and the second direction DR2 may be orthogonal to each other, and the third direction DR3 may be a normal direction relative to the plane defined by the first direction DR1 and the second direction DR2. In the specification, the term "plane" or "plan view" may refer to a plane defined by the first direction DR1 and the second direction DR2, and the term "cross-section" or "cross-section view" may refer to a plane perpendicular to the plane defined by the first direction DR1 and the second direction DR2 and parallel to the third direction DR3. The display device DD may have a thickness direction parallel to the third direction DR3, which is the normal direction relative to the plane defined by the first direction DR1 and the second direction DR2.

[0089] In the present specification, the top surface (or front surface) and the bottom surface (or rear surface) of each component constituting the display device DD may be defined relative to the third direction DR3. For example, of two surfaces of a component facing each other relative to the third direction DR3, the surface relatively adjacent to the display surface DD-IS may be defined as the front surface (or top surface), and the surface relatively spaced apart from the display surface DD-IS may be defined as the rear surface (or bottom surface). In the present specification, an upper portion (or upper side) and a lower portion (or lower side) may be defined relative to the third direction DR3, and the upper portion (or upper side) may be defined in a direction close to the display surface DD-IS, and the lower portion (or lower side) may be defined in a direction away from the display surface DD-IS.

[0090] Figure 2 It is along Figure 1 Schematic cross-sectional view of a portion taken along a virtual line II'. Figure 2 may be a schematic cross-sectional view of a display device according to an embodiment.

[0091] The display device DD may include a display panel DP and an optical member PP disposed on the display panel DP. The display panel DP may include a base substrate BS, a circuit layer DP-CL disposed on the base substrate BS, a display element layer DP-EL disposed on the circuit layer DP-CL, and an encapsulation layer TFE disposed on the display element layer DP-EL.

[0092] The display panel DP may generate a video. The display panel DP may be a light-emitting display panel. For example, the display panel DP may be a quantum dot light-emitting display panel including quantum dot light-emitting elements.

[0093] The base substrate BS may provide a base surface on which the circuit layer DP-CL is disposed. The base substrate BS may be a rigid substrate, or a flexible substrate that is bendable, foldable, or rollable. The base substrate BS may be a glass substrate, a metal substrate, or a polymer substrate. However, the embodiment is not limited thereto, and the base substrate BS may include an inorganic layer, an organic layer, or a composite material layer.

[0094] The circuit layer DP-CL may be disposed on the base substrate BS. The circuit layer DP-CL may include an insulating layer, a semiconductor pattern, a conductive pattern, signal lines, and the like. The insulating layer, semiconductor layer, and conductive layer may be formed on the base substrate BS by methods such as coating or vapor deposition, and may be selectively patterned through repeated photolithography processes. Thus, the insulating layer, semiconductor pattern, conductive pattern, and signal lines included in the circuit layer DP-CL may be formed.

[0095] The display element layer DP-EL may be disposed on the circuit layer DP-CL. The display element layer DP-EL may include a pixel definition layer PDL (see FIG. Figure 4 ) and the first light-emitting element ED-1, the second light-emitting element ED-2 and the third light-emitting element ED-3 (see Figure 4 ). For example, the display element layer DP-EL may include an organic light-emitting material, an inorganic light-emitting material, an organic-inorganic light-emitting material, a quantum dot, a quantum rod, a micro light-emitting diode (LED), or a nano-LED. For example, the display element layer DP-EL may include a quantum dot.

[0096] The encapsulation layer TFE can protect the display element layer DP-EL from moisture, oxygen, and foreign matter such as dust particles. The encapsulation layer TFE may include at least one inorganic layer. The encapsulation layer TFE may include an inorganic layer, an organic layer, and an inorganic layer structure, which may be stacked in this order.

[0097] The optical member PP may be disposed on the display panel DP and may control light reflected at the display panel DP due to external light. The optical member PP may include, for example, a polarizing layer (not shown) or a color filter layer CFL (see FIG. Figure 4 ). Although not shown in the drawings, in an embodiment, the optical member PP may be omitted.

[0098] Figure 3 is a schematic plan view of a display device according to an embodiment. Figure 4 is a schematic cross-sectional view of a display device according to an embodiment. Figure 4 It is along Figure 3 Schematic cross-sectional view of a portion taken along a virtual line II-II'.

[0099] Reference Figure 3 and Figure 4 The display device DD according to the embodiment includes a plurality of light-emitting elements ED-1, ED-2, and ED-3. In the embodiment, the display device DD may include a display panel DP including the light-emitting elements ED-1, ED-2, and ED-3, and an optical member PP provided on the display panel DP. Although not shown in the drawings, the optical member PP may be omitted from the display device DD according to the embodiment.

[0100] The display panel DP may include a base substrate BS, and a circuit layer DP-CL and a display element layer DP-EL provided on the base substrate BS, and the display element layer DP-EL may include a pixel defining film PDL, light emitting elements ED-1, ED-2 and ED-3 arranged between the pixel defining films PDL, and an encapsulation layer TFE arranged on the light emitting elements ED-1, ED-2 and ED-3.

[0101] exist Figure 4 In the embodiment, the base substrate BS may have a single-layer structure or a multi-layer structure. For example, the base substrate BS may include a first synthetic resin layer, an intermediate layer in a multi-layer or single-layer structure, and a second synthetic resin layer, which may be stacked in this order. The intermediate layer may be referred to as a base barrier layer. The intermediate layer may include silicon oxide (SiO x ) layer and an amorphous silicon (a-Si) layer disposed on the silicon oxide layer, but the embodiment is not limited thereto. For example, the intermediate layer may include at least one of a silicon oxide layer, a silicon nitride layer, a silicon oxynitride layer, and an amorphous silicon layer.

[0102] The first synthetic resin layer and the second synthetic resin layer may each include a polyimide resin. In an embodiment, the first synthetic resin layer and the second synthetic resin layer may each include at least one of an acrylate resin, a methacrylate resin, a polyisoprene resin, a vinyl resin, an epoxy resin, a urethane resin, a cellulose resin, a siloxane resin, a polyamide resin, and a perylene resin. In this specification, the term "α" resin may refer to a resin including an "α" functional group.

[0103] The circuit layer DP-CL is disposed on the base substrate BS and may include a plurality of transistors (not shown). The plurality of transistors (not shown) may each include a control electrode, an input electrode, and an output electrode. For example, to drive the light-emitting elements ED-1, ED-2, and ED-3 of the display element layer DP-EL, the circuit layer DP-CL may include a switching transistor and a driving transistor.

[0104] The light emitting regions PXA-R, PXA-G, and PXA-B may be arranged into a plurality of groups according to the colors of light generated from the light emitting elements ED-1, ED-2, and ED-3. Figure 3 and Figure 4 As an example, three light-emitting areas PXA-R, PXA-G, and PXA-B that emit red, green, and blue light, respectively, are shown. For example, the display device DD may include a red light-emitting area PXA-R, a green light-emitting area PXA-G, and a blue light-emitting area PXA-B that are separated from each other.

[0105] The display panel DP may include a plurality of light-emitting elements ED-1, ED-2, and ED-3, and the plurality of light-emitting elements ED-1, ED-2, and ED-3 may emit light in different wavelength regions. The light-emitting elements ED-1, ED-2, and ED-3 may emit light having different colors from each other. For example, the display panel DP 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 embodiment is 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 at least one light-emitting element may emit light in a wavelength region different from the wavelength region of light emitted by the remaining light-emitting elements.

[0106] For example, the blue, green, and red light emitting regions PXA-B, PXA-G, and PXA-R of the display device DD may correspond to the first, second, and third light emitting elements ED-1, ED-2, and ED-3, respectively.

[0107] According to the embodiment, the display device DD may include light emitting elements ED-1, ED-2 and ED-3, and the light emitting elements ED-1, ED-2 and ED-3 may include emission layers EML-B, EML-G and EML-R, and the emission layers EML-B, EML-G and EML-R include quantum dots QD-C1, QD-C2 and QD-C3, respectively.

[0108] The first emission layer EML-B of the first light-emitting element ED-1 may include a first quantum dot QD-C1. The first quantum dot QD-C1 may emit blue light as the first light. The second emission layer EML-G of the second light-emitting element ED-2 and the third emission layer EML-R of the third light-emitting element ED-3 may include a second quantum dot QD-C2 and a third quantum dot QD-C3, respectively. The second quantum dot QD-C2 and the third quantum dot QD-C3 may emit green light as the second light and red light as the third light, respectively.

[0109] In an embodiment, the first light may have a wavelength region within a range of about 410 nm to about 480 nm, the second light may have a wavelength region within a range of about 500 nm to about 570 nm, and the third light may have a wavelength region within a range of about 625 nm to about 675 nm.

[0110] In this specification, a quantum dot may be a crystal of a semiconductor compound. The quantum dot can emit light with various emission wavelengths depending on the size of the crystal. By adjusting the ratio of elements in the quantum dot compound, the quantum dot can emit light with various emission wavelengths.

[0111] The quantum dots may have a diameter in a range of, for example, about 1 nm to about 10 nm.

[0112] Quantum dots can be synthesized by wet chemical processes, metal organic chemical vapor deposition processes, molecular beam epitaxy processes, or processes similar to these processes.

[0113] The wet chemical process is a method in which a precursor material is mixed with an organic solvent to grow quantum dot particle crystals. As the crystals grow, the organic solvent can further serve as a dispersant coordinated to the surface of the quantum dot particles and can control the growth of the crystals. Therefore, the wet chemical process can control the growth of quantum dot particles through a process that is easier to perform and at a lower cost than vapor deposition methods such as metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE).

[0114] The quantum dots QD-C1, QD-C2 and QD-C3 included in the emission layer EML according to the embodiment may be nanocrystals, which may be II-VI semiconductor compounds, III-V semiconductor compounds, III-VI semiconductor compounds, I-III-VI semiconductor compounds, IV-VI semiconductor compounds, II-IV-V semiconductor compounds, Group IV elements, Group IV semiconductor compounds or combinations thereof.

[0115] Examples of II-VI semiconductor compounds may include: binary compounds selected from the group consisting of CdSe, CdTe, CdS, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, and any combination thereof; ternary compounds selected from the group consisting of CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdS, and CdS; The group consisting of dZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, and any combination thereof; a quaternary compound selected from the group consisting of CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, and any combination thereof; and any combination thereof. In an embodiment, the II-VI semiconductor compound may further include a Group I metal and / or a Group IV element. Examples of I-II-VI semiconductor compounds may include CuZnS, etc. Examples of II-IV-VI semiconductor compounds may include ZnSnS, etc. Examples of the Group I-II-IV-VI semiconductor compound may include a quaternary compound selected from the group consisting of Cu 2 ZnSnS 2 , Cu 2 ZnSnS 4 , Cu 2 ZnSnSe 4 , Ag 2 ZnSnS 2 , and any combination thereof.

[0116] Examples of Group III-VI semiconductor compounds may include: binary compounds, such as In 2 S 3 or In 2 Se 3 ; ternary compounds, such as InGaS 3 or InGaSe 3 ; and any combination thereof.

[0117] Examples of Group I-III-VI semiconductor compounds may include: ternary compounds selected from the group consisting of AgInS, AgInS2, CuInS, CuInS2, AgGaS2, CuGaS2, CuGaO2, AgGaO2, AgAlO2 and any combination thereof; or quaternary compounds such as AgInGaS2 or CuInGaS2.

[0118] Examples of III-V semiconductor compounds may include: binary compounds selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and any combination thereof; ternary compounds selected from the group consisting of GaNPs, GaNAs, GaNSb, GaPAs, GaPSb, AlNPs, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InAlP, InNP, InNAs, InNSb, InPAs, InPSb, and any combination thereof; and quaternary compounds selected from the group consisting of GaAlNPs, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNPs, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNPs, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and any combination thereof. In an embodiment, the III-V semiconductor compound may further include a Group II element. Examples of the Group III-V semiconductor compound further including a Group II element may include InZnP and the like.

[0119] Examples of IV-VI semiconductor compounds may include: binary compounds selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe and any combination thereof; ternary compounds selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe and any combination thereof; and quaternary compounds selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe and any combination thereof.

[0120] Examples of the Group II-IV-V semiconductor compound may include a ternary compound selected from the group consisting of ZnSnP, ZnSnP2, ZnSnAs2, ZnGeP2, ZnGeAs2, CdSnP2, CdGeP2, and any combination thereof.

[0121] Examples of Group IV elements may include Si, Ge, and any combination thereof.Examples of Group IV semiconductor compounds may include binary compounds selected from the group consisting of SiC, SiGe, and any combination thereof.

[0122] Each element included in a compound such as a binary compound, a ternary compound, or a quaternary compound may be present in a particle in a uniform concentration distribution or in a non-uniform concentration distribution. For example, the formula of a quantum dot compound may indicate the elements included in the compound, but the ratio of the elements in the compound may vary. For example, AgInGaS2 may indicate AgInGaS2.x Ga 1- x S2 (where x is a real number between 0 and 1).

[0123] In an embodiment, the binary compound, ternary compound, or quaternary compound may be present in the particle with a uniform concentration distribution, or may be present in the particle with a partially non-uniform concentration distribution. In an embodiment, the quantum dot may have a core-shell structure in which one quantum dot surrounds another quantum dot. The quantum dot having a core-shell structure may have a concentration gradient in which the concentration of the element present in the shell decreases toward the core.

[0124] In an embodiment, the quantum dots QD-C1, QD-C2, and QD-C3 may have the above-mentioned core-shell structure, which includes a core comprising nanocrystals and a shell surrounding the core. The shell of each of the quantum dots QD-C1, QD-C2, and QD-C3 may be used as a protective layer to prevent chemical deformation of the core to maintain semiconductor properties, and / or may be used as a charging layer to impart electrophoretic properties to the quantum dots. The shell may be single-layer or multi-layer. Examples of the shells of the quantum dots QD-C1, QD-C2, and QD-C3 may include metal oxides, non-metal oxides, semiconductor compounds, or any combination thereof.

[0125] Examples of metal oxides or non-metal oxides may include binary compounds such as SiO2, Al2O3, TiO2, ZnO, MnO, Mn2O3, Mn3O4, CuO, FeO, Fe2O3, Fe3O4, CoO, Co3O4, or NiO; or ternary compounds such as MgAl2O4, CoFe2O4, NiFe2O4, or CoMn2O4, but embodiments are not limited thereto.

[0126] Examples of semiconductor compounds 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 embodiment is not limited thereto.

[0127] Quantum dots QD-C1, QD-C2, and QD-C3 may each independently have a full width at half maximum (FWHM) of an emission wavelength spectrum less than or equal to about 45 nm. For example, quantum dots QD-C1, QD-C2, and QD-C3 may each independently have a FWHM of an emission wavelength spectrum less than or equal to about 40 nm. For example, quantum dots QD-C1, QD-C2, and QD-C3 may each independently have a FWHM of an emission wavelength spectrum less than or equal to about 30 nm. When the FWHM of the emission wavelength spectrum of quantum dots QD-C1, QD-C2, and QD-C3 falls within any range within the above ranges, color purity or color reproducibility may be improved. The light emitted by quantum dots QD-C1, QD-C2, and QD-C3 may be emitted in all directions so that a wide viewing angle may be improved.

[0128] The form of each of the quantum dots QD-C1, QD-C2, and QD-C3 is not particularly limited and may be any form used in the related art. For example, the quantum dots QD-C1, QD-C2, and QD-C3 may each be spherical, pyramidal, multi-armed, or cubic, or the quantum dots QD-C1, QD-C2, and QD-C3 may each be in the form of nanoparticles, nanotubes, nanowires, nanofibers, nanoplates, or the like.

[0129] With respect to quantum dots QD-C1, QD-C2, and QD-C3, it is possible to control the energy band gap by adjusting the size of the quantum dots or adjusting the ratio of elements in the quantum dot compound, and therefore, light in various wavelength ranges can be obtained from the quantum dot emission layer. Therefore, by using quantum dots as described above (for example, using different sizes of quantum dots or different ratios of elements in quantum dot compounds), a light-emitting element that emits light in various wavelengths can be realized. For example, it is possible to choose to adjust the size of quantum dots QD-C1, QD-C2, and QD-C3 or adjust the ratio of elements in the quantum dot compound to emit blue light, green light, and red light. In an embodiment, quantum dots QD-C1, QD-C2, and QD-C3 can be configured to emit white light by combining light of various colors.

[0130] Quantum dots QD-C1, QD-C2, and QD-C3 can control the color of the emitted light according to their particle size, and thus quantum dots QD-C1, QD-C2, and QD-C3 can have various luminescent colors, such as blue, green, and red. As the particle size of quantum dots QD-C1, QD-C2, and QD-C3 becomes smaller, quantum dots QD-C1, QD-C2, and QD-C3 can emit light in a shorter wavelength region. For example, among quantum dots QD-C1, QD-C2, and QD-C3 having the same core, the particle size of quantum dots emitting green light can be smaller than the particle size of quantum dots emitting red light. In an embodiment, among quantum dots QD-C1, QD-C2, and QD-C3 having the same core, the particle size of quantum dots emitting blue light can be smaller than the particle size of quantum dots emitting green light. However, the embodiments are not limited thereto, and even in quantum dots QD-C1, QD-C2, and QD-C3 having the same core, the particle size of the quantum dots QD-C1, QD-C2, and QD-C3 may be adjusted according to the material used to form the quantum dots QD-C1, QD-C2, and QD-C3 and according to the thickness of the shell.

[0131] When the quantum dots QD-C1, QD-C2, and QD-C3 have various luminescent colors such as blue, green, and red, the quantum dots QD-C1, QD-C2, and QD-C3 having different luminescent colors may have different core materials.

[0132] In embodiments, the first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 may have different diameters. For example, the first quantum dot QD-C1 used in the first light-emitting element ED-1 that emits light in a relatively short wavelength range may have an average diameter that is relatively smaller than the average diameters of the second quantum dot QD-C2 and the third quantum dot QD-C3 of the second light-emitting element ED-2 and the third light-emitting element ED-3, each of which emits light in a relatively long wavelength region.

[0133] In the specification, the term "average diameter" may refer to the arithmetic mean of the diameters of the quantum dot particles. The diameter of the quantum dot particles may be the average of the cross-sectional widths of the quantum dot particles.

[0134] The relationship between the average diameters of the first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 is not limited to the above example. Figure 4The first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 are shown to be similar in size to each other, but the embodiment is not limited thereto. Although not shown in the drawings, in the embodiment, the first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 included in the light-emitting elements ED-1, ED-2, and ED-3 may be different in size. For example, the average diameters of two quantum dots selected from the first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 may be similar, and the remaining quantum dots may have different average diameters.

[0135] In an embodiment, in the light-emitting elements ED-1, ED-2, and ED-3, the emission layers EML-B, EML-G, and EML-R may each include a host and a dopant. In an embodiment, the emission layers EML-B, EML-G, and EML-R may include quantum dots QD-C1, QD-C2, and QD-C3, respectively, as dopant materials. In an embodiment, the emission layers EML-B, EML-G, and EML-R may further include a host material. In an embodiment, in the light-emitting elements ED-1, ED-2, and ED-3, the emission layers EML-B, EML-G, and EML-R may emit fluorescence. For example, quantum dots QD-C1, QD-C2, and QD-C3 may be used as fluorescent dopant materials.

[0136] Although not shown in the drawings, in order to improve dispersibility, the first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 may each have a ligand bonded to their surfaces.

[0137] In the display device DD according to the embodiment, as Figure 3 and Figure 4 As shown in FIG, the light emitting regions PXA-B, PXA-G, and PXA-R may each have an area different from each other. The area may be an area in a plane view defined by the first direction DR1 and the second direction DR2.

[0138] The light-emitting regions PXA-B, PXA-G, and PXA-R may have different areas according to the colors emitted from the emission layers EML-B, EML-G, and EML-R of the light-emitting elements ED-1, ED-2, and ED-3. The blue light-emitting region PXA-B of the first light-emitting element ED-1 that emits blue light may have the largest area, and the green light-emitting region PXA-G of the second light-emitting element ED-2 that emits green light may have the smallest area. However, the embodiment is not limited thereto, and the light-emitting regions PXA-R, PXA-G, and PXA-B may emit light having different colors in addition to red light, green light, and blue light. In an embodiment, the light-emitting regions PXA-R, PXA-G, and PXA-B may have the same area as each other, or the light-emitting regions PXA-R, PXA-G, and PXA-B may have different areas. Figure 3 The areas shown in relative proportions are different from the areas shown in relative proportions.

[0139] The light-emitting regions PXA-B, PXA-G, and PXA-R may be separated from each other by a pixel-defining film PDL. The peripheral region NPXA may be a region between adjacent light-emitting regions PXA-B, PXA-G, and PXA-R, which may correspond to the pixel-defining film PDL. In the specification, the light-emitting regions PXA-B, PXA-G, and PXA-R may each correspond to a pixel.

[0140] exist Figure 4 In the embodiment, the display element layer DP-EL may include a pixel defining layer PDL and first, second, and third light emitting elements ED-1, ED-2, and ED-3. An opening OH may be defined in the pixel defining layer PDL.

[0141] The pixel defining film PDL may separate the light-emitting elements ED-1, ED-2, and ED-3 from one another. The emission layers EML-B, EML-G, and EML-R of the light-emitting elements ED-1, ED-2, and ED-3 may be disposed in an opening OH defined by the pixel defining film PDL and separated from one another. In an embodiment, the first emission layer EML-B of the first light-emitting element ED-1 may be disposed in the first opening OH1, the second emission layer EML-G of the second light-emitting element ED-2 may be disposed in the second opening OH2, and the third emission layer EML-R of the third light-emitting element ED-3 may be disposed in the third opening OH3.

[0142] The pixel defining film PDL may include a polymer resin. For example, the pixel defining film PDL may include a polyacrylate resin or a polyimide resin. In an embodiment, in addition to the polymer resin, the pixel defining film PDL may also include an inorganic material. The pixel defining film PDL may include a light absorbing material, a black pigment, or a black dye. The pixel defining film PDL including the black pigment or the black dye may form a black pixel defining film. When forming the pixel defining film PDL, carbon black or the like may be used as the black pigment or the black dye, but the embodiment is not limited thereto.

[0143] The pixel definition layer PDL may include an inorganic material. For example, the pixel definition layer PDL may include silicon nitride (SiN x ), silicon oxide (SiO x ), silicon oxynitride (SiO x N y ), silicon nitrate (SiN x O y ) etc. The pixel definition film PDL may define the emission areas PXA-B, PXA-G, and PXA-R. The emission areas PXA-B, PXA-G, and PXA-R and the peripheral area NPXA may be separated by the pixel definition film PDL.

[0144] The light-emitting elements ED-1, ED-2 and ED-3 may include a first electrode EL1, hole transport regions HTR-1, HTR-2 and HTR-3 arranged on the first electrode EL1, emission layers EML-B, EML-G and EML-R respectively arranged on the hole transport regions HTR-1, HTR-2 and HTR-3, electron transport regions ETR-1, ETR-2 and ETR-3 respectively arranged on the emission layers EML-B, EML-G and EML-R, and a second electrode EL2 arranged on the electron transport regions ETR-1, ETR-2 and ETR-3.

[0145] Hole transport regions HTR-1, HTR-2 and HTR-3 and electron transport regions ETR-1, ETR-2 and ETR-3 respectively included in the light emitting elements ED-1, ED-2 and ED-3 may be disposed and separated in openings OH1, OH2 and OH3 defined in the pixel defining layer PDL.

[0146] For example, the first hole transport region HTR-1 and the first electron transport region ETR-1 included in the first light-emitting element ED-1 can be disposed adjacent to the first emission layer EML-B and can be patterned in the first opening OH1 in which the first emission layer EML-B is disposed. The second hole transport region HTR-2 and the second electron transport region ETR-2 included in the second light-emitting element ED-2 can be disposed adjacent to the second emission layer EML-G and can be patterned in the second opening OH2 in which the second emission layer EML-G is disposed. The third hole transport region HTR-3 and the third electron transport region ETR-3 included in the third light-emitting element ED-3 can be disposed adjacent to the third emission layer EML-R and can be patterned in the third opening OH3 in which the third emission layer EML-R is disposed. However, the embodiment is not limited thereto, and the hole transport regions HTR-1, HTR-2, and HTR-3 and the electron transport regions ETR-1, ETR-2, and ETR-3 may be provided as a common layer disposed in the emission regions PXA-B, PXA-G, and PXA-R and the peripheral region NPXA.

[0147] In embodiments, hole transport regions HTR-1, HTR-2, and HTR-3 and electron transport regions ETR-1, ETR-2, and ETR-3 may be respectively provided in openings OH1, OH2, and OH3 defined in the pixel defining layer PDL through a printing process.

[0148] The encapsulation layer TFE may cover the light-emitting elements ED-1, ED-2, and ED-3. The encapsulation layer TFE may seal the display element layer DP-EL. The encapsulation layer TFE may be a thin film encapsulation layer. The encapsulation layer TFE may include a single layer or multiple layers. The encapsulation layer TFE may include at least one insulating layer. The encapsulation layer TFE according to an embodiment may include at least one inorganic film (hereinafter, encapsulated inorganic film). The encapsulation layer TFE according to an embodiment may also include at least one organic film (hereinafter, encapsulated organic film) and at least one encapsulated inorganic film.

[0149] The encapsulating inorganic film can protect the display element layer DP-EL from moisture and / or oxygen, and the encapsulating organic film can protect the display element layer DP-EL from foreign matter such as dust particles. The encapsulating inorganic film may include silicon nitride, silicon oxynitride, silicon oxide, titanium oxide, or aluminum oxide, etc., but the embodiment is not particularly limited thereto. The encapsulating organic film may include an acrylic compound or an epoxy compound, etc. The encapsulating organic film may include a photopolymerizable organic material, but the embodiment is not limited thereto.

[0150] The encapsulation layer TFE may be disposed on the second electrode EL2 and may be disposed to fill the openings OH1 , OH2 , and OH3 .

[0151] exist Figure 4 In the display device DD shown in FIG, although the thicknesses of the emission 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 embodiment is not limited thereto. For example, in the embodiment, the thicknesses of the emission 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. In the embodiment, the thicknesses of each of the hole transport regions HTR-1, HTR-2, and HTR-3 and the electron transport regions ETR-1, ETR-2, and ETR-3 of the first light-emitting element ED-1, the second light-emitting element ED-2, and the third light-emitting element ED-3 may also be different from each other.

[0152] Reference Figure 3 The blue light-emitting areas PXA-B and the red light-emitting areas PXA-R may be alternately arranged along the first direction DR1 to form a first group PXG1. The green light-emitting areas PXA-G may be arranged along the first direction DR1 to form a second group PXG2. The first group PXG1 may be spaced apart from the second group PXG2 along the second direction DR2. A plurality of first and second groups PXG1 and PXG2 may be provided. The first and second groups PXG1 and PXG2 may be alternately arranged along the second direction DR2.

[0153] The red light-emitting area PXA-R may be spaced apart from the green light-emitting area PXA-G along the fourth direction DR4. The blue light-emitting area PXA-B may be spaced apart from the green light-emitting area PXA-G along the fifth direction DR5. The fourth direction DR4 may be a direction between the first direction DR1 and the second direction DR2. The fifth direction DR5 may intersect the fourth direction DR4 and may be inclined toward the second direction DR2.

[0154] In an embodiment, Figure 3 The arrangement of the light emitting areas PXA-B, PXA-G, and PXA-R shown in FIG. 1 may be referred to as a pentile arrangement (eg, The arrangement of the light emitting areas PXA-R, PXA-G and PXA-B is not limited to Figure 3 For example, among the light-emitting areas PXA-R, PXA-G, and PXA-B, the red light-emitting area PXA-R, the green light-emitting area PXA-G, and the blue light-emitting area PXA-B may be arranged in this order as a repeating sequence along the first direction DR1. In an embodiment, the shape of each of the light-emitting areas PXA-R, PXA-G, and PXA-B in a plan view is not limited to the shape shown in the drawings and may be defined as a shape different from the shape shown.

[0155] Reference Figure 4The display device DD according to the embodiment may further include an optical member PP. The optical member PP may block external light outside the display device DD from reaching the display panel DP. The optical member PP may block a portion of the external light. The optical member PP may prevent reflection by minimizing reflection of the external light.

[0156] exist Figure 4 In the embodiment shown in FIG, the optical member PP may include a base layer BL and a color filter layer CFL. The display device DD according to the embodiment may further include a color filter layer CFL disposed on the light emitting elements ED-1, ED-2, and ED-3 of the display panel DP.

[0157] The base layer BL may provide a base surface on which the color filter layer CFL is disposed. The base layer BL may be a glass substrate, a metal substrate, a plastic substrate, etc. However, the embodiment is not limited thereto, and the base layer BL may include an inorganic layer, an organic layer, or a composite material layer.

[0158] The color filter layer CFL may include a first filter CF-B, a second filter CF-G, and a third filter CF-R. The first filter CF-B, the second filter CF-G, and the third filter CF-R may be arranged to correspond to the first light-emitting element ED-1, the second light-emitting element ED-2, and the third light-emitting element ED-3, respectively. 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. The first filter CF-B, the second filter CF-G, and the third filter CF-R may be arranged so that they correspond to the first light-emitting area PXA-B, the second light-emitting area PXA-G, and the third light-emitting area PXA-R, respectively.

[0159] The first optical filter CF-B, the second optical filter CF-G, and the third optical filter CF-R may each include a polymerized photosensitive resin and a pigment or dye. The first optical filter CF-B may include a blue pigment or a blue dye, the second optical filter CF-G may include a green pigment or a green dye, and the third optical filter CF-R may include a red pigment or a red dye. However, embodiments are not limited thereto, and the first optical filter CF-B may not include a pigment or a dye. The first optical filter CF-B may include a polymerized photosensitive resin, but may not include a pigment or a dye. The first optical filter CF-B may be transparent. The first optical filter CF-B may be formed of a transparent photosensitive resin.

[0160] The color filter layer CFL may further include a buffer layer BFL. For example, the buffer layer BFL may serve as a protective layer for the first color filter CF-B, the second color filter CF-G, and the third color filter CF-R. The buffer layer BFL may be an inorganic material layer including at least one of silicon nitride, silicon oxide, and silicon oxynitride. The buffer layer BFL may be formed of a single layer or multiple layers.

[0161] In an embodiment, the second filter CF-G and the third filter CF-R may each be a yellow filter. The second filter CF-G and the third filter CF-R may not be provided as separate filters, but may be provided as an integrated filter.

[0162] exist Figure 4 In the embodiment shown in FIG, the first filter CF-B of the color filter layer CFL is shown as overlapping with the second filter CF-G and the third filter CF-R, but the embodiment is 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 a light shielding member (not shown) and may not overlap with each other. In an embodiment, the first filter CF-B, the second filter CF-G, and the third filter CF-R may be provided corresponding to the blue light-emitting area PXA-B, the green light-emitting area PXA-G, and the red light-emitting area PXA-R, respectively. In an embodiment, the color filter layer CFL may be omitted in the display device DD.

[0163] Although not shown in the drawings, the color filter layer CFL may further include a light shielding member (not shown). The light shielding member (not shown) may be a black matrix. The light shielding member (not shown) may include an organic light shielding material or an inorganic light shielding material, each containing a black pigment or dye. The light shielding member can prevent light leakage and can separate the boundaries between adjacent color filters CF-B, CF-G, and CF-R.

[0164] Despite Figure 4 Although not shown in the figure, the display device DD according to the embodiment may include a polarizing layer (not shown) as the optical member PP instead of the color filter layer CFL. The polarizing layer (not shown) may block light reflected from the display panel DP from the outside. The polarizing layer (not shown) may block a portion of the external light.

[0165] In an embodiment, a polarizing layer (not shown) can reduce light reflected from the display panel DP due to external light. For example, the polarizing layer (not shown) can block external light outside the display device DD from entering the display panel DP and then reflecting light that is emitted again through the polarizing layer (not shown). The polarizing layer (not shown) can be a circular polarizer with a reflection prevention function, or the polarizing layer can include a linear polarizer and a λ / 4 phase retarder. The polarizing layer (not shown) can be provided on the base layer BL, or the polarizing layer (not shown) can be provided below the base layer BL.

[0166] Figure 5A is a schematic cross-sectional view of a light emitting element according to an embodiment. Figure 4 At least one of the first light emitting element ED-1, the second light emitting element ED-2, and the third light emitting element ED-3 shown in FIG may each independently have a Figure 5A The structure of the light-emitting element ED is described.

[0167] Reference Figure 5A The light emitting element ED includes a first electrode EL1, a functional layer FCL, and a second electrode EL2, which may be stacked in this order. The functional layer FCL may include a hole transport region HTR, an emission layer EML, and an electron transport region ETR.

[0168] In the light emitting element ED according to the embodiment, the first electrode EL1 may have electrical conductivity, may be formed of a metal alloy or a conductive compound, may be an anode, and may be a pixel electrode.

[0169] In the light-emitting element ED according to the embodiment, the first electrode EL1 may be a reflective electrode. However, the embodiment is not limited thereto. For example, the first electrode EL1 may be a transmissive electrode or a semi-transmissive and semi-reflective electrode. When the first electrode EL1 is a semi-transmissive and semi-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, Mo, Ti, compounds thereof, or mixtures thereof (e.g., a mixture of Ag and Mg), or a material having a multilayer structure such as LiF / Ca or LiF / Al. In the embodiment, the first electrode EL1 may have a multilayer structure including a reflective layer or a semi-transmissive and semi-reflective layer formed of the above materials and a transmissive conductive layer formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), or the like. For example, the first electrode EL1 may include multiple metal layers, such as a stacked structure of ITO / Ag / ITO.

[0170] The hole transport region HTR may be provided on the first electrode EL1. The hole transport region HTR may include a hole injection layer HIL, a hole transport layer HTL, and the like. In an embodiment, 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 of a hole buffer layer (not shown) and an electron blocking layer (not shown). The hole buffer layer (not shown) may compensate for the resonance distance according to the wavelength of light emitted from the emission layer EML, and thus may improve the luminous efficiency. The material that may be included in the hole transport region HTR may be used as the material included in the hole buffer layer (not shown). The electron blocking layer (not shown) may prevent electrons from being injected from the electron transport region ETR into the hole transport region HTR.

[0171] The hole transport region HTR may include nanoparticles NP. In the light emitting element ED according to the embodiment, the nanoparticles NP included in the hole transport region HTR may each include a core CO containing nickel (Ni) and a first metal (see Figure 8 ). The core CO may include a metal oxide in which a first metal is doped into nickel (Ni) oxide. In an embodiment, the first metal may be zinc (Zn), tin (Sn), titanium (Ti), copper (Cu), magnesium (Mg), or chromium (Cr). In an embodiment, the nanoparticles NP may each further include a ligand LG bonded to the surface of the core CO (see Figure 8 ). The nanoparticles NP will be described in detail later.

[0172] The hole transport region HTR may be formed of an ink composition ICP according to an embodiment to be described later (see Figure 8 For example, the hole transport region HTR may be formed by nanoparticles NP and a solvent CV (see Figure 8 ) of the ink composition ICP (see Figure 8 ) is formed. In the specification, the ink composition ICP containing nanoparticles NP (see Figure 8 ) may be referred to as a "hole transport composition".

[0173] When an organic material is used as a hole transport region material in a quantum dot-based optical element, the organic material may degrade when exposed to air, and the organic layer may significantly degrade at a temperature equal to or higher than a certain temperature, thereby reducing the characteristics of the element. In an embodiment, a high temperature process (e.g., a baking process) may be performed to dry the solvent in the quantum dot composition applied during the formation of the emission layer, which may degrade the organic layer disposed thereunder. In order to prevent or avoid such degradation, a method for introducing metal oxide nanoparticles based on inorganic materials into the hole transport region may be applied.

[0174] In an embodiment, nanoparticles NP each including a core CO doped with a first metal in nickel (Ni) oxide can be introduced into the hole transport region HTR, so that even if a high temperature process is performed when manufacturing a quantum dot-based element, there is almost no risk of degradation compared to organic materials, thereby exhibiting high process stability. In an embodiment, in the nanoparticle NP, the energy band of the core CO can be appropriately adjusted by the first metal as a dopant, and thus the hole injection and transport characteristics can be improved, thereby contributing to the charge balance in the emission layer EML. Therefore, the light-emitting element ED including the hole transport region HTR containing the nanoparticle NP can ensure excellent process stability and can achieve high luminous efficiency and long service life. In this specification, the term "energy band" may refer to the valence band and conduction band of the inorganic particle.

[0175] Refer again Figure 5A The hole transport region HTR may have a structure consisting of a layer composed of a single material, a structure consisting of layers including different materials, or a structure including a plurality of layers including different materials. For example, the hole transport region HTR may have a single-layer structure formed of different materials, or may have a structure in which a hole injection layer HIL / hole transport layer HTL, a hole injection layer HIL / hole transport layer HTL / hole buffer layer (not shown), a hole injection layer HIL / hole buffer layer (not shown), a hole transport layer HTL / hole buffer layer (not shown), or a hole injection layer HIL / hole transport layer HTL / electron blocking layer (not shown) are stacked in their respective stated order from the first electrode EL1, but the embodiment is not limited thereto.

[0176] When the hole transport region HTR has a structure including a plurality of layers, at least one of the layers may include the nanoparticles NP according to an embodiment. For example, when the hole transport region HTR has a structure including a plurality of layers, at least one of the layers may be formed from an ink composition ICP (see Figure 8 ) is formed. For example, Figure 5A As shown in FIG, the hole transport region HTR may include a hole injection layer HIL disposed on the first electrode EL1 and a hole transport layer HTL disposed on the hole injection layer HIL, and the hole transport layer HTL may include nanoparticles NP according to an embodiment. Figure 5A Although not shown, in another embodiment, the hole transport layer HTL and the hole injection layer HIL may each include nanoparticles NP.

[0177] The hole transport region HTR may be formed using various methods such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB), inkjet printing, laser printing, and laser induced thermal imaging (LITI). In an embodiment, the electron transport region ETR may be formed by inkjet printing.

[0178] In an embodiment, the hole transport region HTR may further include an inorganic material or an organic material of the related art.

[0179] The hole injection layer HIL may include, for example, a phthalocyanine compound (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-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-phenylethylenedioxythiophene) The products include polyaniline / poly(4-styrenesulfonate) (PANI / PSS), polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), polyaniline / camphorsulfonic acid (PANI / CSA), polyaniline / poly(4-styrenesulfonate) (PANI / PSS), N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPD), triphenylamine-containing polyetherketone (TPAPEK), 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate, dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexanitrile (HAT-CN), etc.

[0180] The hole transport layer HTL may also include materials of related art. For example, the hole transport layer HTL may also include carbazole derivatives (such as N-phenylcarbazole and 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'-di(1-naphth-1-yl)-N,N'-diphenyl-benzidine (NPD), 4,4'-cyclohexylenebis[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.

[0181] The hole transport region HTR may have a thickness in the range of about 5 nm to about 1,500 nm. For example, the hole transport region HTR may have a thickness in the range of about 10 nm to about 500 nm. The hole injection layer HIL may have a thickness in the range of, for example, about 3 nm to about 200 nm, and the hole transport layer HTL may have a thickness in the range of about 3 nm to about 100 nm. For example, the electron blocking layer (not shown) may have a thickness in the range of about 1 nm to about 100 nm. If the thicknesses of the hole transport region HTR, the hole injection layer HIL, the hole transport layer HTL and the electron blocking layer (not shown) meet the above ranges, satisfactory hole transport properties can be achieved without significantly increasing the driving voltage.

[0182] The emission layer EML may be provided on the hole transport region HTR. For example, the emission layer EML may have a thickness in the range of about 10 nm to about 100 nm. For example, the emission layer EML may have a thickness in the range of about 10 nm to about 30 nm. The emission layer EML may have a structure consisting of a layer composed of a single material, a structure consisting of layers including different materials, or a structure including a plurality of layers including different materials. In the light emitting element ED according to the embodiment, the emission layer EML may include quantum dots QD-C. The quantum dots QD-C may be Figure 4 One of the first quantum dot QD-C1, the second quantum dot QD-C2 and the third quantum dot QD-C3 is the same.

[0183] The emission layer EML can be formed by using various methods such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB), inkjet printing, laser printing, and laser induced thermal imaging (LITI). In an embodiment, the emission layer EML can be formed by providing a quantum dot composition including quantum dots QD-C via an inkjet printing method.

[0184] In the light emitting element ED according to the embodiment, an electron transport region ETR may be provided on the emission layer EML. The electron transport region ETR may include at least one of a hole blocking layer (not shown), an electron transport layer ETL, and an electron injection layer EIL, but the embodiment is not limited thereto.

[0185] The electron transport region ETR may have a structure consisting of a layer composed of a single material, a structure consisting of layers including different materials, or a structure including a plurality of layers including different materials.

[0186] 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, and may have a single-layer structure formed of an electron injection material and an electron transport material. In an embodiment, the electron transport region ETR may have a structure including different materials, or may have a structure in which the electron transport layer ETL / electron injection layer EIL or the hole blocking layer (not shown) / electron transport layer ETL / electron injection layer EIL are stacked in their respective order of presentation from the emission layer EML, but the embodiment is not limited thereto. The thickness of the electron transport region ETR may be, for example, in the range of about 20 nm to about 150 nm.

[0187] The electron transport region ETR may be formed using various methods such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) method, inkjet printing, laser printing, and laser induced thermal imaging (LITI).

[0188] In an embodiment, the electron transport region ETR may include an inorganic material or an organic material of the related art.

[0189] When the electron transport region ETR includes the electron transport layer ETL, the electron transport region ETR may include an anthracene compound. However, the embodiment is not limited thereto, and the electron transport region ETR may include, for example, tris(8-hydroxyquinoline)aluminum (Alq3), 1,3,5-tris[(3-pyridyl)-phenyl-3-yl]benzene, 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, bis[2-(diphenylphosphine)phenyl]ether oxide (DPEPO), 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-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4-(naphthalene-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-hydroxyquinolinolato-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum (BAlq), bis(benzoquinolinolato-10-hydroxy)beryllium (Bebq2), 9,10-di(naphthalene-2-yl)anthracene (ADN), or a mixture thereof. The thickness of the electron transport layer ETL may be in the range of about 10 nm to about 100 nm. For example, the thickness of the electron transport layer ETL may be in the range of about 15 nm to about 50 nm. When the thickness of the electron transport layer ETL satisfies any of the above ranges, satisfactory electron transport properties may be obtained without significantly increasing driving voltage.

[0190] When the electron transport region ETR includes an electron injection layer EIL, the electron transport region ETR may include: metal halides such as LiF, NaCl, CsF, RbCl, and RbI; lanthanide metals such as Yb; metal oxides such as Li2O and BaO; or lithium quinolate (LiQ), etc., but the embodiment is not limited thereto. The electron injection layer EIL may also be formed from a mixture of an electron transport material and an insulating organic metal salt. For example, the organic metal salt may include a metal acetate, a metal benzoate, a metal acetoacetate, a metal acetylacetonate, or a metal stearate. The thickness of the electron injection layer EIL may be in the range of about 0.1 nm to about 10 nm. For example, the thickness of the electron injection layer EIL may be in the range of about 0.3 nm to about 9 nm. When the thickness of the electron injection layer EIL satisfies any of the above ranges, satisfactory electron injection properties may be obtained without causing a significant increase in the driving voltage.

[0191] The electron transport region ETR may include a hole blocking layer (not shown) as described above. The hole blocking layer (not shown) may include, for example, at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and 4,7-diphenyl-1,10-phenanthroline (Bphen), but the embodiment is not limited thereto.

[0192] The second electrode EL2 may be provided 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 semi-reflective electrode, or a reflective electrode. When the second electrode EL2 is a transmissive electrode, the second electrode EL2 may include a transparent metal oxide (e.g., indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), etc.).

[0193] When the second electrode EL2 is a semi-transmissive and semi-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, Mo, Ti, a compound thereof, or a mixture thereof (e.g., a mixture of Ag and Mg), or a material having a multilayer structure such as LiF / Ca or LiF / Al. In an embodiment, the second electrode EL2 may have a multilayer structure including a reflective layer or a semi-transmissive and semi-reflective layer formed of the above materials and a transparent conductive layer formed of ITO, IZO, ZnO, ITZO, or the like.

[0194] Although not shown in the drawings, the second electrode EL2 may be electrically connected to the auxiliary electrode. When the second electrode EL2 is electrically connected to the auxiliary electrode, the resistance of the second electrode EL2 may be reduced.

[0195] Figure 5B is a schematic cross-sectional view of a light emitting element according to an embodiment. Figure 5B Shown with Figure 5A The structure of the light-emitting element ED shown in FIG is different from that of the light-emitting element ED-a. Figure 4 At least one of the first light emitting element ED-1, the second light emitting element ED-2, and the third light emitting element ED-3 shown in FIG may each independently have a Figure 5B The structure of the light-emitting element ED-a is described. Figure 5B In the description of Figures 1 to 5A The features described are described, and the different features will be described.

[0196] and Figure 5A Compared with the light emitting element ED shown in Figure 5B The light-emitting element ED-a shown in FIG. 1 is different from the light-emitting element ED in at least that the electron transport region ETR may include inorganic particles MP.

[0197] In embodiments, the inorganic particles MP may include metal oxides or metalloid oxides including silicon, aluminum, zinc, indium, gallium, yttrium, germanium, scandium, titanium, tantalum, hafnium, zirconium, cerium, molybdenum, nickel, chromium, iron, niobium, tungsten, tin, copper, or any mixture thereof, but embodiments are not limited thereto.

[0198] In an embodiment, the inorganic particles MP may include at least one of zinc oxide and tin oxide. The type of zinc oxide is not limited and may be ZnO doped with Sn, Mg, or Ca. Tin oxide may be SnO, SnO2, or any combination thereof.

[0199] In an embodiment, the inorganic particles MP may include at least one of ZnO, ZnSnO, ZnMgO, SnO 2 , and ZnGaO.

[0200] The electron transport region ETR may be formed from an electron transport composition containing inorganic particles MP. For example, the electron transport region ETR may be formed from an electron transport composition including inorganic particles MP and a solvent. The solvent used for the electron transport composition may be the same as that for the ink composition ICP described below (see Figure 8 ) is the same as described for the solvent.

[0201] In order to improve the luminous efficiency characteristics and service life characteristics of the quantum dot light-emitting element, a method for introducing an inorganic metal oxide into the electron transport region ETR can be used. When the electron transport region ETR in the quantum dot light-emitting element is formed by a composition including an inorganic metal oxide, a high temperature process can be used to dry the solvent in the composition. When the hole transport region HTR provided in the lower portion is formed by an organic material, the organic material included in the hole transport region HTR may deteriorate in the high temperature process, and thus the luminous efficiency and service life of the light-emitting element may be reduced. In an embodiment, each of the core CO (see FIG. 1 ) doped with a first metal in nickel (Ni) oxide Figure 8 Nanoparticles NP can be introduced into the hole transport region HTR, resulting in little risk of degradation compared to organic materials even when performing high-temperature processes, thereby exhibiting high process stability. In embodiments, the energy band of the core CO can be appropriately adjusted by the first metal as a dopant, thereby improving hole injection and transport characteristics, thereby contributing to charge balance in the emission layer EML. Therefore, light-emitting elements ED and ED-a including a hole transport region HTR containing nanoparticles NP can ensure excellent process stability and achieve high luminous efficiency and a long service life.

[0202] Figure 6 is a flowchart of a method for manufacturing a light emitting element according to an embodiment. Figure 7is a flowchart of a dividing step for forming a hole transport region according to an embodiment.

[0203] Reference Figure 6 The method for manufacturing a light-emitting element includes a step S100 of forming a hole transport region on a first electrode, a step S200 of forming an emission layer on the hole transport region, a step S300 of forming an electron transport region on the emission layer, and a step S400 of forming a second electrode on the electron transport region.

[0204] Reference Figure 7 According to an embodiment, the step S100 of forming the hole transport region includes the step S101 of preparing an ink composition, the step S102 of providing a preliminary hole transport region, and the step S103 of heat-treating the preliminary hole transport region.

[0205] Figure 8 : is a schematic cross-sectional view of an ink composition according to an embodiment. The ink composition ICP according to the embodiment may be a material for forming a hole transport region of a light emitting element. However, the embodiment is not limited thereto, and the ink composition ICP may be a material for forming an electron transport region ETR (see Figure 5A and Figure 5B ) or emission layer EML (see Figure 5A and Figure 5B ) in any layer.

[0206] Reference Figure 8 The ink composition ICP according to an embodiment may include nanoparticles NP and a solvent CV. The nanoparticles NP may each include a core CO and a ligand LG bonded to a surface of the core CO.

[0207] Core CO may include a metal oxide comprising nickel (Ni) and a first metal. Core CO may be a metal oxide in which the first metal is doped into nickel (Ni) oxide. In an embodiment, the first metal may be zinc (Zn), tin (Sn), titanium (Ti), copper (Cu), magnesium (Mg) or chromium (Cr). For example, the first metal may be zinc (Zn). Core CO may be formed by replacing nickel (Ni) ions with a first metal in NiO, and may exhibit improved stability and excellent electrical and optical properties. The first metal may be doped into a metal oxide comprising nickel (Ni) to control the hole mobility of the nickel oxide, and may improve the chemical stability of the nanoparticles NP. Therefore, a hole transport region HTR (see FIG. 1 ) formed by the ink composition ICP according to an embodiment is included. Figure 5A and Figure 5B ) of the light-emitting element ED (see Figure 5A ) can ensure excellent process stability and achieve high luminous efficiency and long service life.

[0208] In an embodiment, the core CO may be represented by Equation 1:

[0209] [Formula 1]

[0210] Ni 1-x M x O.

[0211] In Formula 1, M may be Zn, Sn, Ti, Cu, Mg, or Cr. In an embodiment, M may be Zn.

[0212] In Formula 1, x may satisfy 0<x<1. In an embodiment, x may satisfy 0.01≤x<0.03. When x is greater than or equal to about 0.03, due to excessive doping of the first metal, some electrons in the emission layer EML may leak into the hole transport region HTR, and thus the element efficiency may deteriorate. When x is less than 0.01, charge imbalance due to degradation of the hole injection characteristic may be caused, thereby deteriorating the element characteristics. In Formula 1, when x satisfies any range within the above ranges, optimal hole injection characteristics may be exhibited, and thus the luminous efficiency characteristics and service life characteristics of the light-emitting element ED may be further improved.

[0213] The nanoparticle NP may further include a ligand LG bonded to the surface of the core CO. The ligand LG may improve the stability of the core CO to prevent adverse reactions due to oxygen or moisture, etc., and may increase the distance between adjacent core COs to prevent aggregation of the nanoparticle NP.

[0214] In an embodiment, the ligand LG may include a head, a linker connected to the head, and a tail connected to the linker. The head may be bonded to the surface of the core CO. The ligand LG may be bonded to the surface of the core CO. When the head includes a single functional group to be bonded to the surface of the core CO, the ligand LG may be a monodentate ligand. When the head includes two functional groups to be bonded to the surface of the core CO, the ligand LG may be a bidentate ligand. The head may include a functional group to be bonded to the surface of the core CO, so that the ligand LG can effectively bond to the core CO.

[0215] The head group may be an electron donor head group. In an embodiment, the head group may be any one of a hydroxyl group, a thiol group, an amine group, a carboxylic acid group, a dithiocarboxylic acid group, a phosphine group, and a catechol group.

[0216] The ligand LG may include a tail. The tail may be connected to the head. In an embodiment, the head may be bonded to the surface of the core CO, and the tail may be exposed to the outside of the nanoparticle NP. In an embodiment, the tail may include a hydroxyl group, a thiol group, a substituted or unsubstituted oxy group, a substituted or unsubstituted thiol group, a substituted or unsubstituted (meth)acrylate group, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, or a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms.

[0217] In an embodiment, the ligand LG may include a 2-methoxyethoxy group. The tail of the ligand LG may include a 2-methoxyethoxy group. The 2-methoxyethoxy group may increase the dispersibility of the core CO when the core CO is dispersed in the solvent CV. In the specification, the term "2-methoxyethoxy" may refer to a group represented by *-OCH2CH2OCH3.

[0218] The ligand LG may include a linker. The linker of the ligand LG may be connected to the head. The linker may connect the head and the tail. For example, the ligand LG may include a head, a linker, and a tail, and the linker may be connected to the head, and the tail may be connected to the linker. In an embodiment, the linker may be a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms, a substituted or unsubstituted alkenylene group having 2 to 30 carbon atoms, a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring carbon atoms. For example, the linker may be a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms. In the ligand LG, one or more linkers may be provided. However, embodiments are not limited thereto, and the linker may be omitted from the ligand.

[0219] In an embodiment, the ligand LG can be represented by formula L:

[0220] [Formula L]

[0221] R a -(L a ) z -OCH2CH2OCH3.

[0222] In formula L, R a It can be a hydroxyl group, a thiol group, an amine group, a carboxylic acid group, a dithiocarboxylic acid group, a phosphine group or a catechol group. a It can be a thiol group, an amine group or a carboxylic acid group.

[0223] In formula L, L aIt may be a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms, a substituted or unsubstituted alkenylene group having 2 to 30 carbon atoms, a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring carbon atoms. a It may be a substituted or unsubstituted methylene group, or a substituted or unsubstituted ethylene group.

[0224] In Formula L, z may be an integer from 0 to 10. For example, z may be 1.

[0225] In formula L, R a Can correspond to the above head, and *-OCH2CH2OCH3 can correspond to the above tail. In formula L, when z is 1 or greater, L a It can correspond to the above-mentioned connection part.

[0226] In an embodiment, the ligand LG may include at least one of 2-(2-methoxyethoxy)ethylamine, 2-(2-methoxyethoxy)acetic acid, and 2-(2-methoxyethoxy)ethanethiol. The nanoparticles NP according to an embodiment may include the ligand LG attached to the surface of the core CO and may include a 2-methoxyethoxy group, thereby improving the surface stability of the core CO and exhibiting excellent dispersibility and excellent stability over time in the ink composition ICP.

[0227] In embodiments, the amount of the ligand LG bonded to the surface of the core CO may be in a range of about 10 wt % to about 30 wt % relative to 100 wt % of the total weight of the nanoparticle NP.

[0228] When the amount of ligand LG in the nanoparticles NP is less than or equal to approximately 10 wt%, the surface stability of the core CO may deteriorate, and the luminous efficiency and lifetime of the light-emitting element ED may be reduced. When the amount of ligand LG in the nanoparticles NP is less than or equal to approximately 10 wt%, the dispersibility and temporal stability of the nanoparticles NP may be reduced, and solution processability may be degraded. When the amount of ligand LG in the nanoparticles NP is greater than or equal to approximately 30 wt%, the hole transport and hole injection properties of the core CO may deteriorate, and charge balance may collapse in the light-emitting element ED, thereby degrading the luminous efficiency and lifetime. When the amount of ligand LG in the nanoparticles NP falls within the above range, excellent hole transport and hole injection properties can be exhibited, and the luminous efficiency and lifetime of the light-emitting element ED can be improved. When the amount of ligand LG in the nanoparticles NP falls within the above range, excellent dispersion stability and temporal stability can be achieved, and solution processability can be improved.

[0229] In the specification, the amount of the ligand LG may mean the amount of the ligand LG present on the surface of the core CO in the nanoparticle NP. The amount of the ligand LG may be measured by thermogravimetric analysis (TGA), but the embodiment is not limited thereto.

[0230] In an embodiment, the ink composition ICP may further include an additive AT. The additive AT may be included in the ink composition ICP and may improve the dispersion stability of the nanoparticles NP. When the ink composition ICP includes the additive AT, the dispersion stability of the nanoparticles NP may be improved, and thus, solution processability may be further improved.

[0231] In an embodiment, the additive AT may be represented by Formula 2:

[0232]

[0233]

[0234] In Formula 2, R1 to R3 may each independently be a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms. In an embodiment, R1 to R3 may each independently be a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms. For example, R1 to R3 may each independently be a substituted or unsubstituted methyl group, or a substituted or unsubstituted ethyl group.

[0235] In Formula 2, R4 may be a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 30 ring carbon atoms, a substituted or unsubstituted arylene group having 6 to 60 ring carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 60 ring carbon atoms. In an embodiment, R4 may be a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms.

[0236] In Formula 2, a1 to a3 may each independently be 0 or 1. In an embodiment, at least one of a1 to a3 may be 1. For example, any one of a1 to a3 may be 1, and the other two may be 0. For example, two of a1 to a3 may be 1, and the other may be 0. For example, a1 to a3 may each be 1.

[0237] In Formula 2, F1 may be a substituted or unsubstituted (meth)acrylate group, a substituted or unsubstituted epoxy group, or a substituted or unsubstituted amine group. For example, F1 may be a substituted or unsubstituted (meth)acrylate group.

[0238] In an embodiment, the additive AT represented by Formula 2 may be represented by one of Formulas 3-1 to 3-5:

[0239]

[0240] The ink composition ICP according to the embodiment may include a solvent CV. The solvent CV may be an organic solvent or an inorganic solvent such as water. The organic solvent may include an aprotic solvent or a protic solvent.

[0241] For example, the aprotic solvent may include hexane, toluene, chloroform, dimethyl sulfoxide, octane, xylene, hexadecane, cyclohexylbenzene, triethylene glycol monobutyl ether, dimethylformamide, decane, dodecane, hexadecene, tetralin, ethylnaphthalene, ethylbiphenyl, isopropylnaphthalene, diisopropylnaphthalene, diisopropylbiphenyl, xylene, isopropylbenzene, pentylbenzene, diisopropylbenzene, decahydronaphthalene, phenylnaphthalene, cyclohexyldecahydronaphthalene, decylbenzene, dodecylbenzene, octylbenzene, cyclohexane, cyclopentane, cycloheptane, etc., but the embodiment is not limited thereto.

[0242] The protic solvent may be a compound that can provide at least one proton. For example, the protic solvent may be a compound containing at least one dissociable proton. For example, the protic solvent may include a protic liquid material or a protic polymer. The protic solvent may include, for example, methanol, ethanol, propanol, isopropanol, ethylene glycol, propylene glycol, or diethylene glycol, but embodiments are not limited thereto.

[0243] In an embodiment, the solvent CV may include a polyethylene glycol portion. The solvent CV may include a polyethylene glycol portion and a first substituent connected to the end of the polyethylene glycol portion. In an embodiment, the first substituent may be an alkyl group, a cycloalkyl group, a heterocycloalkyl group, a silyl group, an aryl group, or a heteroaryl group. Since the ink composition ICP includes a solvent including a polyethylene glycol portion and a first substituent, the dispersion stability of the nanoparticles NP may be improved, and thus, the solution processability may be improved. In the specification, the first substituent may be R corresponding to Formula 4 described below. 13 substituents.

[0244] In an embodiment, the solvent CV can be represented by Formula 4:

[0245] [Formula 4]

[0246] R 11 -O-(R 12 -O) n -R 13 .

[0247] In formula 4, R 11 It can be a hydrogen atom or a deuterium atom. For example, R 11 It may be a hydrogen atom.

[0248] In formula 4, R 12 It may be a substituted or unsubstituted alkylene group having 1 to 60 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 10 ring carbon atoms, a substituted or unsubstituted heterocycloalkylene group having 2 to 10 ring carbon atoms, a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring carbon atoms. For example, R 12 It may be a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms. For example, R 12 It may be a substituted or unsubstituted ethylene group or a substituted or unsubstituted isopropylene group.

[0249] In formula 4, R 13 It may be a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 ring carbon atoms, a substituted or unsubstituted heterocycloalkyl group having 2 to 10 ring carbon atoms, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms. In an embodiment, R 13 It may be a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted heterocycloalkyl group having 2 to 10 ring carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms. 13 It may be substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted n-propyl, substituted or unsubstituted isopropyl, substituted or unsubstituted tert-butyl, substituted or unsubstituted isopentyl, substituted or unsubstituted benzyl, or substituted or unsubstituted tetrahydrofuranyl.

[0250] In Formula 4, n may be an integer from 1 to 5. For example, n may be an integer from 1 to 3.

[0251] In an embodiment, the solvent CV may be represented by one of Formulas 4-1 to 4-3:

[0252]

[0253] In formulas 4-1 to 4-3, R 11 、R 13 and n may be the same as described in Formula 4.

[0254] In an embodiment, the solvent CV may be represented by one of Formulas 5-1 to 5-8:

[0255]

[0256]

[0257] The ink composition ICP according to an embodiment may include a solvent CV represented by Formula 4, and thus, the dispersion stability of the nanoparticles NP in the ink composition ICP may be improved. In an embodiment, since the solvent CV represented by Formula 4 is introduced into the ink composition ICP including the nanoparticles NP, the dispersion stability of the nanoparticles NP may be improved, thereby improving solution processability.

[0258] Figures 9A to 9C Each is a schematic cross-sectional view of a method step for manufacturing a light-emitting element according to an embodiment.

[0259] Figure 9A The step S102 of providing a preliminary hole transport region among the steps in the method for manufacturing a light emitting element according to the embodiment (see Figure 7 The step S102 of providing a preliminary hole transport region may be a step of applying an ink composition ICP on the first electrode EL1.

[0260] In an embodiment, the method of applying the ink composition ICP is not particularly limited, and a spin coating method, a casting method, an LB (Langemuir-Blodgett) method, an inkjet printing method, a laser printing method, a laser induced thermal imaging method (LITI), etc. may be used. For example, the ink composition ICP may be applied to the first electrode EL1 by using an inkjet printing method. Figure 9A It is shown that the ink composition ICP may be applied into the space between the pixel defining films PDL through the nozzles NZ, but the embodiment is not limited thereto.

[0261] Figure 9B This is step S103 of heat-treating the preliminary hole transport region in the method for manufacturing a light-emitting element according to an embodiment (see Figure 7 The step S103 of heat-treating the preliminary hole transport region may be a step of providing heat LT to the preliminary hole transport region P-HTR and heat-treating the preliminary hole transport region P-HTR at a first temperature for a selected time.

[0262] Solvent CV (see Figure 8 ) can be removed by step S103 of heat-treating the preliminary hole transport region, and thus, a uniform thin film can be formed. In an embodiment, the first temperature is not particularly limited, but may be in the range of about 50°C to about 350°C. For example, the first temperature may be in the range of about 200°C to about 300°C. However, the embodiment is not limited thereto, and the temperature and time of the heat treatment step at the first temperature may be appropriately selected according to the type and capacity of the material.

[0263] Reference Figure 9C, after the step of forming the hole transport region HTR, the step of forming the emission layer EML, the step of forming the electron transport region ETR, and the step of forming the second electrode EL2 may be sequentially performed.

[0264] In an embodiment, the step of forming the emission layer EML may include providing a hole transport region HTR including quantum dots QD-C (see Figure 5A and Figure 5B ) of the quantum dot composition to form a preliminary emission layer and a step of heat treating the preliminary emission layer. The quantum dot composition may include quantum dots QD-C (see Figure 5A and Figure 5B ) and solvent. Quantum dots QD-C can be used with Figure 4 The contents of the first quantum dot QD-C1, the second quantum dot QD-C2 and the third quantum dot QD-C3 described above are the same.

[0265] The solvent included in the quantum dot composition can be removed by the step of heat-treating the preliminary emission layer, and thus, a uniform thin film can be formed. The step of heat-treating the preliminary emission layer can be performed under a second temperature condition. The second temperature is not particularly limited, but can be, for example, in the range of about 50°C to about 350°C. For example, the second temperature can be in the range of about 200°C to about 300°C. However, the embodiment is not limited thereto, and the temperature and time of the heat treatment step at the second temperature can be appropriately selected according to the type and capacity of the material.

[0266] After forming the emission layer EML, an electron transport region ETR may be formed on the emission layer EML. The electron transport region ETR may be formed by various methods such as spin coating, casting, Langmuir-Blodgett (LB), inkjet printing, laser printing, and laser induced thermal imaging (LITI).

[0267] In an embodiment, the step of forming the electron transport region ETR may be performed by an inkjet printing method or a spin coating method. In an embodiment, the step of forming the electron transport region ETR may include the steps of providing an electron transport composition on the emission layer EML to form a preliminary electron transport region and heat treating the preliminary electron transport region. The electron transport composition may include inorganic particles MP (see Figure 5B ) and solvent. The inorganic particles MP included in the electron transport composition can be the same as those described above. Figure 5B The contents of the inorganic particles MP described are the same.

[0268] The solvent included in the electron transport composition can be removed by the step of heat treating the preliminary electron transport region, and thus, a uniform thin film can be formed. The step of heat treating the preliminary electron transport region can be performed under a third temperature condition. The third temperature is not particularly limited, but can be in the range of about 50°C to about 350°C. For example, the third temperature can be in the range of about 200°C to about 300°C. However, the embodiment is not limited thereto, and the temperature and time of the heat treatment step at the third temperature can be appropriately selected according to the type and capacity of the material.

[0269] In the method of manufacturing a light emitting element according to an embodiment, when the electron transport region ETR is formed of an electron transport composition, a structure having Figure 5B Light-emitting element ED-a having the structure shown in FIG.

[0270] However, the embodiment is not limited thereto, and the step of forming the electron transport region ETR may be a step of depositing an electron transport material on the emission layer EML. Figure 5A The light emitting element ED shown in FIG. 1 can be formed by forming the electron transport region ETR. The electron transport material used to form the electron transport region ETR can be the electron transport material used in the above reference. Figure 5A Materials for the electron transport region (ETR) are described.

[0271] although Figures 9A to 9C It is shown that the hole transport region HTR and the electron transport region ETR are each provided between the pixel defining films PDL, but the embodiment is not limited thereto, and the hole transport region HTR and the electron transport region ETR may each be provided in the form of a common layer overlapping the pixel defining film PDL.

[0272] Hereinafter, nanoparticles according to an embodiment, an ink composition according to an embodiment, and a light-emitting element according to an embodiment will be described with reference to examples and comparative examples. The examples described below are merely illustrations for helping to understand the embodiments, and their scope is not limited thereto.

[0273] [Examples and comparative examples]

[0274] 1. Synthesis of the nucleus

[0275] (Synthesis Example 1: Ni 0.99 Zn 0.01 O core)

[0276] Nickel acetate (II) tetrahydrate (9.9 mmol), zinc acetate dihydrate (0.1 mmol) and dimethyl sulfoxide (80 mL) were injected into the reactor and stirred for about 240 minutes. The temperature of the reactor was adjusted to 30 ° C, and a mixed solution of 1M tetramethylammonium hydroxide pentahydrate (TMAH) and ethanol (10 mL) was injected therein for 10 minutes. After the TMAH solution was injected, the reaction was maintained for 2 hours, and the synthesized Ni was precipitated using acetone and n-hexane. 0.99 Zn 0.01 O inorganic particles and disperse them in the ink.

[0277] (Synthesis Example 2: Ni 0.98 Zn 0.02 O core)

[0278] Nickel acetate (II) tetrahydrate (9.8mmol), zinc acetate dihydrate (0.2mmol) and dimethyl sulfoxide (80mL) were injected into the reactor and stirred for about 240 minutes. The temperature of the reactor was adjusted to 30°C, and a mixed solution of 1M tetramethylammonium hydroxide pentahydrate (TMAH) and ethanol (10mL) was injected therein for 10 minutes. After the TMAH solution was injected, the reaction was maintained for 2 hours, and the synthesized Ni was precipitated using acetone and n-hexane. 0.98 Zn 0.02 O inorganic particles and disperse them in the ink.

[0279] (Synthesis Example 3: Ni 0.97 Zn 0.03 O core)

[0280] Nickel acetate (II) tetrahydrate (9.7 mmol), zinc acetate dihydrate (0.3 mmol) and dimethyl sulfoxide (80 mL) were injected into the reactor and stirred for about 240 minutes. The temperature of the reactor was adjusted to 30 ° C, and a mixed solution of 1M tetramethylammonium hydroxide pentahydrate (TMAH) and ethanol (10 mL) was injected therein for 10 minutes. After the TMAH solution was injected, the reaction was maintained for 2 hours, and the synthesized Ni was precipitated using acetone and n-hexane. 0.97 Zn 0.03 O inorganic particles and disperse them in the ink.

[0281] (Synthesis Example 4: Ni 0.98 Mg 0.02 O core)

[0282] Nickel acetate (II) tetrahydrate (9.8mmol), magnesium acetate tetrahydrate (0.2mmol) and dimethyl sulfoxide (80mL) are injected into the reactor and stirred for about 240 minutes. The temperature of the reactor is adjusted to 30°C, and a mixed solution of 1M tetramethylammonium hydroxide pentahydrate (TMAH) and ethanol (10mL) is injected therein for 10 minutes. After the TMAH solution is injected, the reaction is maintained for 2 hours, and the Ni (II) synthesized by acetone and n-hexane precipitation is added. 0.98 Mg 0.02 O inorganic particles and disperse them in the ink.

[0283] (Synthesis Example 5: Ni 0.98 Sn 0.02 O core)

[0284] Nickel acetate (II) tetrahydrate (9.8 mmol), tin chloride (II) (0.2 mmol) and dimethyl sulfoxide (80 mL) were injected into the reactor and stirred for about 240 minutes. The temperature of the reactor was adjusted to 30 ° C, and a mixed solution of 1M tetramethylammonium hydroxide pentahydrate (TMAH) and ethanol (10 mL) was injected therein for 10 minutes. After the TMAH solution was injected, the reaction was maintained for 2 hours, and the synthesized Ni was precipitated using acetone and n-hexane. 0.98 Sn 0.02 O inorganic particles and disperse them in the ink.

[0285] (Synthesis Example 6: NiO x nuclear)

[0286] Nickel acetate (II) tetrahydrate (10 mmol) and dimethyl sulfoxide (80 mL) were injected into the reactor and stirred for about 240 minutes. The temperature of the reactor was adjusted to 30 ° C, and a mixed solution of 1M tetramethylammonium hydroxide pentahydrate (TMAH) and ethanol (10 mL) was injected therein for 10 minutes. After the TMAH solution was injected, the reaction was maintained for 2 hours, and the synthesized NiO was precipitated using acetone and n-hexane. x Inorganic particles and disperse them in ink.

[0287] 2. Preparation of ink composition

[0288] Ink compositions containing nanoparticles of Examples and Comparative Examples were prepared as shown in Table 1. In Examples 1-1 to 1-5 and Comparative Example 1-2, nanoparticles having a ligand bonded to the core surface were used, and in Comparative Example 1-1, nanoparticles not having a ligand bonded to the core surface were used.

[0289] [Table 1]

[0290]

[0291] 3. Evaluation of ink composition

[0292] Table 2 shows the evaluation of the jetting properties and average particle size of the ink compositions of Examples and Comparative Examples. In Table 2, the jetting properties were evaluated immediately after each ink composition was ejected from the inkjet device (Day 0) and 7 days after ejection (Day 7). The jetting properties were based on a droplet accuracy of ±20 μm, and a Dimatix material printer DMP-2850 was used as the inkjet device. The average particle size was measured immediately after the ink composition was allowed to stand at room temperature (Day 0) and 21 days after the ink composition was allowed to stand at room temperature (Day 21), and their results are shown in Table 2. In Table 2, particle size was measured using a DLS device (Nano-ZS90 manufactured by Malvern). The smaller the difference between the initial average particle size and the average particle size after 21 days, the better the dispersion stability for the solvent.

[0293] [Table 2]

[0294]

[0295] Referring to Table 2, it can be confirmed that Examples 1-1 to 1-5 and Comparative Example 1-2 have good ejection properties even after the ink composition has been left to stand for 7 days, compared to Comparative Example 1-1. Therefore, it can be confirmed that Examples 1-1 to 1-5 and Comparative Example 1-2 have improvements in storage stability and ejection properties by including nanoparticles containing ligands bonded to the core surface.

[0296] It was confirmed that the difference between the initial average particle size and the average particle size after 21 days was smaller for Examples 1-1 to 1-5 and Comparative Example 1-2 than for Comparative Example 1-1. It was confirmed that the average particle size after 21 days was significantly increased for Comparative Example 1-1. Therefore, it was confirmed that the ink compositions of Examples 1-1 to 1-5 and Comparative Example 1-2, which include nanoparticles comprising a core and a ligand bonded to the core surface, exhibited excellent dispersion stability. For example, in the case of the ink compositions of Examples 1-1 to 1-5 and Comparative Example 1-2, it is expected that the dispersion stability of the nanoparticles is improved, and thus, solution processability can be further improved.

[0297] 4. Manufacturing of light-emitting elements

[0298] (Manufacturing in Example 2-1)

[0299] An ITO glass substrate (50 mm×50 mm, 15 Ω / cm 2 ) as a glass substrate for EL-QD (Samsung-Corning Co., Ltd.) was cleaned sequentially using distilled water and isopropyl alcohol. 2 ), and subjected it to ultraviolet cleaning and ozone cleaning for 30 minutes. PEDOT:PSS (CleviosTM HIL8) was spin-coated on the cleaned ITO glass substrate to form a 100 nm thick film, and baked at about 120°C for about 10 minutes to form a hole injection layer. Ink composition 1 was spin-coated on the hole injection layer to form a 40 nm thick film, and baked at about 50°C-350°C for about 30 minutes to form a hole transport layer. Green InP quantum dots dispersed in octane were spin-coated on the hole transport layer to form a 40 nm thick film, and baked at about 100°C for about 10 minutes to form a green emission layer. ZnMgO inorganic nanoparticles were spin-coated on the green emission layer to form a 36 nm thick film, and baked at 200°C for about 10 minutes to form an electron transport layer. After the glass substrate was mounted on the substrate holder of the vacuum deposition equipment, AgMg was deposited on the electron transport layer to form a 20 nm thick anode, thereby manufacturing a quantum dot light-emitting element. The equipment used for deposition was a Suicel plus 200 evaporator from Sunic System.

[0300] (Manufacturing in Example 2-2)

[0301] An element was manufactured in the same manner as in Example 2-1, except that Ink Composition 2 was used instead of Ink Composition 1 in forming the hole transport layer.

[0302] (Manufacturing in Example 2-3)

[0303] An element was manufactured in the same manner as in Example 2-1, except that ink composition 3 was used instead of ink composition 1 in forming the hole transport layer.

[0304] (Manufacturing in Example 2-4)

[0305] An element was manufactured in the same manner as in Example 2-1, except that ink composition 4 was used instead of ink composition 1 in forming the hole transport layer.

[0306] (Manufacturing in Example 2-5)

[0307] An element was manufactured in the same manner as in Example 2-1, except that ink composition 5 was used instead of ink composition 1 in forming the hole transport layer.

[0308] (Manufacturing in Comparative Example 2-1)

[0309] An element was manufactured in the same manner as in Example 2-1, except that comparative poly(9-vinylcarbazole) (PVK) was used instead of ink composition 1 in forming the hole transport layer.

[0310] (Manufacturing in Comparative Example 2-2)

[0311] An element was manufactured in the same manner as in Example 2-1, except that comparative NiO was used instead of ink composition 1 in forming the hole transport layer.

[0312] 5. Evaluation of light-emitting elements

[0313] The driving voltage, efficiency and service life of the quantum dot light emitting elements manufactured in Examples 2-1 to 2-5 and Comparative Examples 2-1 and 2-2 were measured, and the results are shown in Table 3. Table 3 shows the 1280 cd / m 2 The driving voltage and efficiency under brightness. The service life (T90) is when 10mA / cm 2 When the initial brightness is set to 100%, the time (hours) required for the brightness to reach 90%.

[0314] [Table 3]

[0315]

[0316] Referring to Table 3, it can be confirmed that the efficiency and service life of the light-emitting elements of Examples 2-1 to 2-5 and Comparative Example 2-2, to which nickel oxide is applied, are increased compared to the light-emitting element of Comparative Example 2-1, to which PVK is applied. It can be seen that the light-emitting elements of Examples 2-1 to 2-5 and Comparative Example 2-2, including the hole injection layer to which nickel oxide is applied, exhibit higher efficiency characteristics and longer service life characteristics than the light-emitting element of Comparative Example 2-1, including the hole injection layer to which an organic material is applied. The efficiency and service life of quantum dot light-emitting elements are greatly affected by the charge balance between electrons and holes in the emission layer. To balance the charge, the hole injection and transport characteristics of the hole injection layer should be properly controlled, and the stability should also be high. Organic materials such as PVK are materials that can be used as hole transport materials for quantum dot light-emitting elements. These organic materials are good for injecting holes, but they may degrade when exposed to air, and may degrade significantly above a certain temperature, thereby degrading the characteristics of the element. When manufacturing quantum dot light-emitting elements, a high-temperature process can be used to dry the solvent of the quantum dot composition applied to the emission layer. However, since the organic layer below the emission layer is highly likely to degrade during the high-temperature process, there is a limitation in the efficiency and service life of the light-emitting element. Therefore, the light-emitting element of Comparative Example 2-1, which includes a hole transport layer formed of an organic material, may exhibit degraded characteristics in terms of luminous efficiency and stability compared to the light-emitting elements of Examples 2-1 to 2-5, which use a metal oxide in which the first metal is doped into nickel as the hole transport layer material. In contrast, Examples 2-1 to 2-5 can exhibit higher chemical stability than Comparative Example 2-1 by using a metal oxide in which the first metal is doped into nickel as the hole transport layer material. Therefore, when the hole transport region is formed using the ink composition of Examples 2-1 to 2-5, high stability can be exhibited even in a high-temperature process, and therefore, high efficiency and long service life can be expected compared to the light-emitting element of Comparative Example 2-1.

[0317] When comparing Example 2-1 to Example 2-3, it can be confirmed that Example 2-3 including nanoparticles having an atomic ratio of the first metal of less than 0.03 has degradation in efficiency and service life compared to Example 2-1 and Example 2-2 including nanoparticles having an atomic ratio of the first metal of less than 0.03.

[0318] When Comparative Example 2-1 and Comparative Example 2-2 are compared together, Comparative Example 2-2 to which NiO is applied exhibits higher efficiency and longer service life than Comparative Example 2-1. NiO has a work function similar to that of PEDOT:PSS and has a wide band gap, and therefore has good hole injection and transport characteristics. Here, the properties of the NiO nanoparticles can be modified by doping with a first metal, and therefore the hole transport and injection characteristics can be adjusted. Referring to Examples 2-1 to 2-3, it can be confirmed that as the doping concentration of Zn increases to 0.02, the efficiency and service life are improved compared to Comparative Example 2-2 to which undoped NiO is applied, but as the doping concentration of Zn further increases to 0.03, the efficiency and service life decrease compared to Comparative Example 2-2. This is believed to be because the excessive doping of Zn leads to the degradation of the hole injection and transport characteristics of the hole transport layer, resulting in the collapse of the charge balance of the light-emitting element. Therefore, by adjusting the ratio of nickel to the first metal in the nanoparticles, the hole injection and transport characteristics of the hole transport region can be precisely controlled, and thus, the charge balance in the emissive layer can be optimized. For example, when the atomic ratio of the first metal in the nanoparticles is adjusted to less than 0.03, the charge balance in the quantum dot emissive layer is optimized, thereby improving the efficiency and service life of the light-emitting element.

[0319] In the embodiment, since the nanoparticles NP represented by Formula 1 (see Figure 8 ) can be included in the ink composition forming the hole transport zone, so that the dispersion stability and stability over time can be improved, and thus a uniform thin film can be formed, and the charge balance of the element can be controlled by hole injection control and hole transport control. Therefore, when the hole transport zone is formed using the ink composition according to the embodiment, the luminous efficiency characteristics and service life characteristics of the light-emitting element can be improved. By adjusting the ratio of nickel and the first metal in the nanoparticles, the hole transport and injection characteristics of the nanoparticles can be controlled to improve the charge injection balance of the light-emitting element. Therefore, when the hole transport zone is formed by applying the ink composition of the embodiment, the current density in the element can be increased, and ultimately the luminous efficiency and service life of the display device can be improved.

[0320] The light emitting element according to the embodiment may exhibit improved element characteristics with high efficiency and long lifespan.

[0321] The ink composition according to the embodiment may contribute to high efficiency and long lifespan of the light emitting element.

[0322] The embodiment may provide a method for manufacturing a light emitting element with improved process reliability.

[0323] Embodiments have been disclosed herein, and although terminology is employed, such terminology is used and is to be interpreted in a generic and descriptive sense only and not for purposes of limitation. In some cases, unless otherwise specifically noted, as will be apparent to one of ordinary skill in the art, features, characteristics, and / or elements described in connection with an embodiment may be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments. Accordingly, it will be understood by one of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present disclosure as set forth in the claims.

Claims

1. A light-emitting element, wherein: The light emitting element comprises: a first electrode; a second electrode, disposed on the first electrode; an emission layer disposed between the first electrode and the second electrode; and A hole transport region is provided between the first electrode and the emission layer, wherein the hole transport region comprises a plurality of nanoparticles, wherein: Each of the plurality of nanoparticles includes a core represented by Formula 1: [Formula 1] In 1-x M x SHE, In formula 1, M is Zn, Sn, Ti, Cu, Mg or Cr, and x satisfies 0<x<1.

2. The light-emitting element according to claim 1, wherein x satisfies 0.01≤x<0.

03.

3. The light-emitting element according to claim 1, wherein M is Zn. The light-emitting element according to claim 1 , wherein Each of the plurality of nanoparticles further includes a ligand bonded to a surface of the core.

5. The light-emitting element according to claim 4, wherein The ligand includes at least one of 2-(2-methoxyethoxy)ethylamine, 2-(2-methoxyethoxy)acetic acid, and 2-(2-methoxyethoxy)ethanethiol. The light-emitting element according to claim 4 , wherein The amount of the ligand is in the range of 10 wt % to 30 wt % relative to 100 wt % of the total weight of the nanoparticles.

7. The light-emitting element according to claim 1, wherein The hole transport region further includes an additive represented by Formula 2: [Formula 2] In formula 2, R1 to R3 are each independently a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, R4 is a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 30 ring carbon atoms, a substituted or unsubstituted arylene group having 6 to 60 ring carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 60 ring carbon atoms, a1 to a3 are each independently 0 or 1, provided that at least one of a1 to a3 is 1, and F1 is a substituted or unsubstituted (meth)acrylate group, a substituted or unsubstituted epoxy group, or a substituted or unsubstituted amine group.

8. The light-emitting element according to claim 7, wherein The additive is represented by one of Formulas 3-1 to 3-5: [Formula 3-1] 9. The light-emitting element according to claim 1, wherein The emission layer includes quantum dots.

10. The light-emitting element according to claim 1, wherein The light emitting element further comprises: An electron transport region is provided between the second electrode and the emission layer, wherein: The electron transport region includes a metal oxide. The light-emitting element according to claim 10 , wherein The metal oxide includes at least one of ZnO, ZnSnO, ZnMgO, SnO2 and ZnGaO.

12. An ink composition comprising a plurality of nanoparticles, wherein: Each of the plurality of nanoparticles includes a core represented by Formula 1: [Formula 1] In 1-x M x SHE, In formula 1, M is Zn, Sn, Ti, Cu, Mg or Cr, and x satisfies 0.01≤x<0.

03.

13. The ink composition according to claim 12, wherein M is Zn.

14. The ink composition according to claim 12, wherein Each of the plurality of nanoparticles further includes a ligand bonded to a surface of the core.

15. The ink composition according to claim 14, wherein The ligand includes at least one of 2-(2-methoxyethoxy)ethylamine, 2-(2-methoxyethoxy)acetic acid, and 2-(2-methoxyethoxy)ethanethiol.

16. The ink composition according to claim 14, wherein The amount of the ligand is in the range of 10 wt % to 30 wt % relative to 100 wt % of the total weight of the nanoparticles.

17. The ink composition according to claim 12, wherein The ink composition further includes an additive represented by Formula 2: In formula 2, R1 to R3 are each independently a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, R4 is a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 30 ring carbon atoms, a substituted or unsubstituted arylene group having 6 to 60 ring carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 60 ring carbon atoms, a1 to a3 are each independently 0 or 1, provided that at least one of a1 to a3 is 1, and F1 is a substituted or unsubstituted (meth)acrylate group, a substituted or unsubstituted epoxy group, or a substituted or unsubstituted amine group.

18. A method for manufacturing a light emitting element, wherein: The method comprises: forming a hole transport region on the first electrode; forming an emission layer on the hole transport region; forming an electron transport region on the emission layer; and A second electrode is formed on the electron transport region, wherein The forming of the hole transport region includes: Prepare the ink composition according to any one of claims 12 to 17; providing the ink composition on the first electrode to form a preliminary hole transport region; and The preliminary hole transport region is subjected to a heat treatment.

19. The method according to claim 18, wherein The forming of the emission layer includes: providing a quantum dot composition including quantum dots on the hole transport region to form a preliminary emission layer; and The preliminary emission layer is subjected to heat treatment.

20. The method according to claim 18, wherein The forming of the electron transport region includes: providing an electron transport composition including a metal oxide on the emission layer to form a preliminary electron transport region; and The preliminary electron transport region is subjected to a heat treatment.

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