Light-emitting element, method for manufacturing light-emitting element, and display device

Abstract

Embodiments provide a light emitting element, a method for manufacturing the light emitting element, and a display device. The light emitting element includes: a first electrode; a light emitting layer disposed on the first electrode, the light emitting layer including quantum dots; a second electrode disposed on the light emitting layer; a hole transport region disposed between the first electrode and the second electrode; and an electron transport region disposed between the first electrode and the second electrode, the electron transport region including metal nanoparticles. The light emitting layer is disposed between the hole transport region and the electron transport region. The metal nanoparticle includes a core comprising a metal oxide, and a ligand bonded to the core. The ligand may include a bisulfite salt derived from an ionic compound represented by Formula A-1, which is explained in the specification. [Formula A-1] # imgabs0 #

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the priority and benefit of Korean Patent Application No. 10-2024-0001359, filed with the Korean Intellectual Property Office on January 4, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a light-emitting element including metal nanoparticles, a method for manufacturing a light-emitting element, and a display device including the light-emitting element. Background Art

[0004] A light-emitting element has a property of converting electrical energy into light energy. Among light-emitting elements, a quantum dot light-emitting element including quantum dots has high color purity and high luminous efficiency, and can emit multi-color light. Holes generated in the light-emitting element move to the light-emitting layer through a hole transport region, and electrons generated in the light-emitting element move to the light-emitting layer through an electron transport region. In order to improve the luminous efficiency, research has been conducted to promote the injection and transport of holes and electrons in the quantum dot light-emitting element.

[0005] It will be understood that this background art section is intended in part to provide a useful background for understanding the present technology. However, this background art section may also include ideas, concepts, or knowledge that were not known or understood by those skilled in the relevant art before the effective filing date of the corresponding subject matter disclosed herein. Summary of the Invention

[0006] The present disclosure provides a light-emitting element having high luminous efficiency and a display device including the light-emitting element.

[0007] The present disclosure also provides a method for manufacturing a light-emitting element that is excellent in manufacturing efficiency.

[0008] According to an embodiment, the light-emitting element may include: a first electrode; a light-emitting layer disposed on the first electrode, the light-emitting layer including quantum dots; a second electrode disposed on the light-emitting layer; a hole transport region disposed between the first electrode and the second electrode; and an electron transport region disposed between the first electrode and the second electrode, the electron transport region including metal nanoparticles, wherein

[0009] the light-emitting layer may be disposed between the hole transport region and the electron transport region, the metal nanoparticles may include a core containing a metal oxide and a ligand bonded to the core, and the ligand may include a bisulfite derived from an ionic compound represented by Formula A-1:

[0010] [Formula A-1]

[0011]

[0012] In Formula A-1, Mp may be Zn, Li, Be, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Rb, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Sb, or Ba, and represents an ionic bond.

[0013] In an embodiment, the ligand may include a first ligand containing a bisulfite anion in Formula A-1 and a second ligand containing Mp in Formula A-1.

[0014] In an embodiment, the first ligand and the second ligand may each be bonded to the surface of the core.

[0015] In an embodiment, based on 100 mol% of the total moles of the metal nanoparticles, the moles of bisulfite may range from about 5 mol% to about 20 mol%.

[0016] In an embodiment, the metal oxide may include at least one of SnO, SnO2, CuGaO2, Ga2O3, Cu2O, SrCu2O2, SrTiO3, CuAlO2, Ta2O5, NiO, BaSnO3, and TiO2; or the metal oxide may be represented by Formula M-1:

[0017] [Formula M-1]

[0018] Zn (1-q) Me q O

[0019] In Formula M-1, q may be a real number from 0 to 0.5; and Me may be Li, Be, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Rb, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Sb, or Ba.

[0020] In an embodiment, the quantum dots may not include cadmium.

[0021] In an embodiment, a hole transport region may be disposed between the first electrode and the light-emitting layer, and an electron transport region may be disposed between the light-emitting layer and the second electrode.

[0022] In an embodiment, a hole transport region may be disposed between the light-emitting layer and the second electrode, and an electron transport region may be disposed between the first electrode and the light-emitting layer.

[0023] According to an embodiment, a method for manufacturing a light-emitting element may include: forming a first electrode; forming a light-emitting layer on the first electrode; forming a second electrode on the light-emitting layer; forming a hole transport region; and forming an electron transport region by providing a composition including metal nanoparticles, wherein

[0024] one of the steps of forming the hole transport region and forming the electron transport region may be performed between the formation of the first electrode and the formation of the light-emitting layer, and the other of the steps of forming the hole transport region and forming the electron transport region may be performed between the formation of the light-emitting layer and the formation of the second electrode; and the metal nanoparticles may include a core containing a metal oxide and a ligand bonded to the core, and the ligand includes a bisulfite salt derived from an ionic compound represented by Formula A-1:

[0025] [Formula A-1]

[0026]

[0027] In Formula A-1, Mp may be Zn, Li, Be, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Rb, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Sb, or Ba, and represents an ionic bond.

[0028] In an embodiment, the method may further include generating metal nanoparticles before the formation of the electron transport region, wherein

[0029] the generation of the metal nanoparticles may include generating a core and providing an ionic compound to the core to generate metal nanoparticles in which the ligand is bonded to the surface of the core.

[0030] In an embodiment, the generation of the core may include: preparing a solution including a first metal precursor containing a first metal, a second metal precursor containing a second metal different from the first metal, and a first solvent; and providing a second solvent different from the first solvent, and

[0031] the first metal and the second metal may each independently include Li, Be, Na, Mg, Al, K, Ca, Ta, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Rb, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Zn, Sb, or Ba.

[0032] In an embodiment, the first metal precursor may be a zinc precursor, the second metal precursor may be a magnesium precursor, and the zinc precursor and the magnesium precursor may each independently include an acetate ion or a halogen ion.

[0033] In an embodiment, the first solvent may include at least one of ethanol and dimethyl sulfoxide (DMSO).

[0034] In an embodiment, the second solvent may include at least one of potassium hydroxide, sodium hydroxide, trimethylammonium hydroxide (TMAM), and tetramethylammonium hydroxide (TMAH).

[0035] In an embodiment, based on 100 mol% of the total moles of the metal nanoparticles, the moles of bisulfite may range from about 5 mol% to about 20 mol%.

[0036] In an embodiment, the composition may be provided by an inkjet printing method or a dispensing method.

[0037] According to an embodiment, a display device may include a substrate layer and a display element layer disposed on the substrate layer, the display element layer including a light-emitting element, wherein

[0038] the light-emitting element may include: a first electrode; a light-emitting layer disposed on the first electrode, the light-emitting layer including quantum dots; a second electrode disposed on the light-emitting layer; a hole transport region disposed between the first electrode and the second electrode; an electron transport region, the electron transport region including metal nanoparticles, the light-emitting layer may be disposed between the hole transport region and the electron transport region, and the metal nanoparticles may include a core containing a metal oxide and a ligand bonded to the core, the ligand including a bisulfite derived from an ionic compound represented by Formula A-1:

[0039] [Formula A-1]

[0040]

[0041] In Formula A-1, Mp may be Zn, Li, Be, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Rb, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Sb, or Ba, and represents an ionic bond.

[0042] In an embodiment, the ligand may include a first ligand containing the bisulfite in Formula A-1 and a second ligand containing Mp in Formula A-1.

[0043] In an embodiment, the first ligand and the second ligand may each be bonded to the surface of the core.

[0044] In an embodiment, based on 100 mol% of the total moles of the metal nanoparticles, the moles of bisulfite may range from about 5 mol% to about 20 mol%.

[0045] In the embodiment, the metal oxide may include at least one of SnO, SnO2, CuGaO2, Ga2O3, Cu2O, SrCu2O2, SrTiO3, CuAlO2, Ta2O5, NiO, BaSnO3, and TiO2; or the metal oxide may be represented by Formula M-1:

[0046] [Formula M-1]

[0047] Zn (1-q) Me q O

[0048] In Formula M-1, q may be a real number from 0 to 0.5; and Me may be Li, Be, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Rb, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Sb, or Ba.

[0049] It will be understood that the above embodiments are described only in a general and illustrative sense and not for the purpose of limitation, and the present disclosure is not limited to the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] 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 drawings illustrate embodiments of the present disclosure and their principles. By describing the embodiments of the present disclosure in detail with reference to the accompanying drawings, the above and other aspects and features of the present disclosure will become more apparent. In the drawings:

[0051] Figure 1 is a schematic perspective view of a display device according to an embodiment;

[0052] Figure 2 is Figure 1 a schematic cross-sectional view of a portion corresponding to the virtual line I-I' of

[0053] Figure 3 is a schematic plan view of a display device according to an embodiment;

[0054] Figure 4A is Figure 3 a schematic cross-sectional view of a portion corresponding to the virtual line II-II' of

[0055] Figure 4B is a schematic cross-sectional view of a display device according to another embodiment;

[0056] Figure 5A is a schematic cross-sectional view of a light-emitting element according to an embodiment;

[0057] Figure 5B is a schematic cross-sectional view of a light-emitting element according to an embodiment;

[0058] Figure 5C is a schematic cross-sectional view of a light-emitting element according to an embodiment;

[0059] Figure 5D is a schematic cross-sectional view of a light-emitting element according to an embodiment;

[0060] Figure 6 is a schematic cross-sectional view of metal nanoparticles according to an embodiment;

[0061] Figure 7 is Figure 6 an enlarged schematic view of region XX' of

[0062] Figure 8A is a graph showing the results of evaluating the light-emitting elements in Experimental Examples 1 to 6;

[0063] Figure 8B is a graph showing the results of evaluating the light-emitting elements in Experimental Examples 1 to 6;

[0064] Figure 8C is a graph showing the results of evaluating the light-emitting elements in Experimental Examples 1 to 6;

[0065] Figure 9A is a flowchart of a method for manufacturing a light-emitting element according to an embodiment;

[0066] Figure 9B is a flowchart of a method for manufacturing a light-emitting element according to an embodiment;

[0067] Figure 10 is a schematic view of steps for manufacturing a light-emitting element according to an embodiment;

[0068] Figure 11A is a schematic view of steps for manufacturing a light-emitting element according to an embodiment;

[0069] Figure 11B is a schematic view of steps for manufacturing a light-emitting element according to an embodiment; and

[0070] Figure 12 is Figure 11A an enlarged schematic view of region AA' of Detailed Description

[0071] The present disclosure will be described more fully hereinafter with reference to the accompanying drawings that illustrate embodiments of the present disclosure. However, the present disclosure may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0072] In the drawings, for ease of description and clarity, the size, thickness, proportion, and dimensions of elements may be exaggerated. The same reference numerals and / or the same reference characters always refer to the same elements.

[0073] In the description, it will be understood that when an element (or region, layer, part, etc.) is referred to as being "on" another element, "connected to" another element, or "coupled to" another element, the element may be directly on, connected to, or coupled to the other element, or there may be one or more intervening elements between the element and the other element. In a similar sense, when an element (or region, layer, part, etc.) is described as "covering" another element, the element may directly cover the other element, or there may be one or more intervening elements between the element and the other element.

[0074] In the description, when an element is "directly on" another element, "directly connected to" another element, or "directly coupled to" another element, there are no intervening elements. For example, "directly on" may mean that two layers or two elements are disposed together and there are no additional elements such as adhesive elements therebetween.

[0075] Unless the context clearly indicates otherwise, as used herein, singular forms such as "a," "an," and "the" are also intended to include the plural forms.

[0076] As used herein, the term "and / or" includes any combination and all combinations of one or more of the associated listed items. For example, "A and / or B" can be understood as "A, B, or A and B." The terms "and" and "or" may be used in a conjunctive or disjunctive sense and can be understood as equivalent to "and / or."

[0077] In the specification and claims, for purposes of their meaning and interpretation, 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" can 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, AC, BC, or AB. When following a list of elements, the term "at least one of" modifies the entire list of elements and not a single element in the list.

[0078] It will be understood that although the terms "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, without departing from the teachings of the present disclosure, a first element may be referred to as a second element. Similarly, without departing from the teachings of the present disclosure, a second element may also be referred to as a first element.

[0079] As shown in the accompanying drawings, for ease of description, the spatial relative terms such as "below", "beneath", "under", "above" or "on" may be used herein to describe the relationship between one element or component and another element or component. It will be understood that, in addition to the orientation described in the drawings, the spatial relative terms are also intended to cover different orientations of the device during use or operation. For example, in the case where the device shown in the drawings is flipped, a device positioned "below" or "beneath" another device may be placed "above" the other device. Thus, the illustrative term "below" may include both the lower and upper positions. The device may also be oriented in other directions, and thus the spatial relative terms may be interpreted differently according to different orientations.

[0080] Taking into account the measurements discussed and the errors associated with a particular number of measurements (e.g., limitations of the measurement system), as used herein, the terms "about" or "approximate" include the stated value and mean within an acceptable deviation range of the particular value determined by a person of ordinary skill in the art. For example, "about" may mean within one or more standard deviations, or within ±20%, ±10% or ±5% of the stated value.

[0081] It should be understood that the terms "comprises / comprising", "includes / including", "have / having" and "contains / containing" are intended to specify the presence of the stated features, integers, steps, operations, elements, components or groups 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 groups thereof.

[0082] Unless otherwise defined or implied herein, all terms used (including technical and scientific terms) have the same meaning as commonly understood by a person of ordinary skill in the art to which this disclosure pertains. It will be further understood that terms (such as those defined in a common dictionary) 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 unless expressly defined in the specification.

[0083] Hereinafter, a light-emitting element according to an embodiment and a display device including the light-emitting element will be described with reference to the drawings. Figure 1 is a schematic perspective view of a display device DD according to an embodiment.

[0084] Referring to Figure 1 , the display device DD according to an embodiment can be activated in response to an electrical signal. For example, the display device DD can be a large device such as a television, a monitor, or a billboard. In an embodiment, 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 unit, a game console, a smart phone, or a camera. However, these are provided only as examples, and the display device DD can also be included in other devices.

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

[0086] Pixels PX can be provided in the display area DA, and pixels PX can not be provided in the non-display area NDA. The non-display area NDA can be defined along the edge of the display surface DD-IS. The non-display area NDA can surround the display area DA. However, the embodiment is not limited thereto. For example, the non-display area NDA can be omitted or provided only on one side of the display area DA.

[0087] Figure 1 shows that the display device DD can include a flat display surface DD-IS, but the embodiment is not limited thereto. For example, in an embodiment, the display surface DD-IS of the display device DD can be a curved display surface or a three-dimensional display surface. The three-dimensional display surface can include a plurality of display areas arranged in different directions.

[0088] In Figure 1In the following drawings, a first direction axis DR1, a second direction axis DR2, and / or a third direction axis DR3 are shown. In the specification, the directions indicated by the first direction axis DR1, the second direction axis DR2, and the third direction axis DR3 are relative terms and can thus be changed to other directions. The directions indicated by the first direction axis DR1, the second direction axis DR2, and the third direction axis DR3 can be described as a first direction DR1, a second direction DR2, and a third direction DR3 and can be represented by the same reference numerals or reference numbers. In the specification, the first direction axis DR1 and the second direction axis DR2 can intersect at a right angle, and the third direction axis DR3 can be the normal direction of the plane defined by the first direction axis DR1 and the second direction axis DR2.

[0089] In the specification, a plan view can refer to a view in the plane defined by the first direction axis DR1 and the second direction axis DR2, and a cross-sectional view can refer to a view perpendicular to the plane defined by the first direction axis DR1 and the second direction axis DR2 and parallel to the third direction axis DR3. The thickness direction of the display device DD can be a direction parallel to the third direction DR3, which is the normal direction of the plane defined by the first direction DR1 and the second direction DR2.

[0090] In the specification, the upper surface (or front surface) and the lower surface (or rear surface) of each of the plurality of members constituting the display device DD can be defined according to the third direction DR3. For example, among the two surfaces of a member that face each other with respect to the third direction DR3, the surface relatively adjacent to the display surface DD-IS can be defined as the front surface (or upper surface), and the surface spaced apart from the display surface DD-IS can be defined as the rear surface (or lower surface). In the specification, an upper portion (or upper side surface) and a lower portion (or lower side surface) can be defined with respect to the third direction DR3, and the upper portion (or upper side surface) can be defined as the direction approaching the display surface DD-IS, and the lower portion (or lower side surface) can be defined as the direction away from the display surface DD-IS.

[0091] Figure 2 is Figure 1 a schematic cross-sectional view of a portion corresponding to the imaginary line I-I' of Figure 2 a schematic cross-sectional view of a display device DD according to an embodiment.

[0092] The display device DD can include a display panel DP and an optical layer PP provided on the display panel DP. The display panel DP can include a substrate layer BS, a circuit layer DP-CL provided on the substrate layer BS, a display element layer DP-EL provided on the circuit layer DP-CL, and a packaging layer TFE provided on the display element layer DP-EL.

[0093] The display panel DP can be a component that generates static images and / or dynamic images. The display panel DP can be a light-emitting display panel. For example, the display panel DP can be a quantum dot light-emitting display panel including quantum dot light-emitting elements.

[0094] The substrate layer BS can provide a substrate surface on which the circuit layer DP-CL is disposed. The substrate layer BS can be a rigid substrate; or the substrate layer BS can be a flexible substrate capable of being bent, folded, curled, etc. The substrate layer BS can be a glass substrate, a metal substrate, a polymer substrate, etc. However, the embodiments are not limited thereto, and the substrate layer BS can include an inorganic layer, an organic layer, or a composite material layer.

[0095] The circuit layer DP-CL can be disposed on the substrate layer BS. The circuit layer DP-CL can include an insulating layer, a semiconductor pattern, and a conductive pattern for forming signal lines, etc. The insulating layer, the semiconductor layer, and the conductive layer can be formed on the substrate layer BS by coating, deposition, etc., and the insulating layer, the semiconductor layer, and the conductive layer can be selectively patterned by multiple cycles of photolithography processes. Thereafter, a semiconductor pattern included in the circuit layer DP-CL and a conductive pattern for forming signal lines, etc. can be formed.

[0096] The display element layer DP-EL can be disposed on the circuit layer DP-CL. The display element layer DP-EL can include a pixel defining layer PDL (see Figure 4A and Figure 4B ) to be described later, and a first light-emitting element ED-1, a second light-emitting element ED-2, and a third light-emitting element ED-3 (see Figure 4A and Figure 4B ). For example, the display element layer DP-EL can include an organic light-emitting material, an inorganic light-emitting material, an organic-inorganic light-emitting material, quantum dots, quantum rods, micro light-emitting diodes (LEDs), or nano LEDs. For example, the display element layer DP-EL can include quantum dots.

[0097] The encapsulation layer TFE can protect the display element layer DP-EL from moisture, oxygen, and foreign substances such as dust particles. The encapsulation layer TFE can include at least one inorganic layer. In an embodiment, the encapsulation layer TFE can have a structure in which an inorganic layer, an organic layer, and an inorganic layer are stacked in sequence.

[0098] The optical layer PP can be disposed on the display panel DP and can control the light reflected from external light to the display panel DP. For example, the optical layer PP can include a polarization layer or a color filter layer. Although not shown in the figure, in an embodiment, the optical layer PP can also be omitted.

[0099] Figure 3 is a schematic plan view of a display device DD according to an embodiment.Figure 4A is a schematic cross-sectional view of a portion corresponding to the virtual line II-II' of Figure 3 . Figure 3 may be a schematic plan view showing the display area DA of the display device DD (see Figure 1 ). Figure 4A may be a schematic cross-sectional view showing a portion of the display device DD according to an embodiment.

[0100] Referring to Figure 3 and Figure 4A , the display device DD may include a peripheral area NPXA and light-emitting areas PXA-B, PXA-G, and PXA-R. The light-emitting areas PXA-B, PXA-G, and PXA-R may be areas where light emitted from the light-emitting elements ED-1, ED-2, and ED-3, respectively, is emitted. The light-emitting areas PXA-B, PXA-G, and PXA-R may each have a different area, where the area may be the area in the plan view.

[0101] According to the colors of the light generated from the light-emitting elements ED-1, ED-2, and ED-3, the light-emitting areas PXA-B, PXA-G, and PXA-R may be arranged in groups. Figure 3 and Figure 4A show three light-emitting areas PXA-B, PXA-G, and PXA-R that emit blue light, green light, and red light, respectively. For example, the display device DD may include a blue light-emitting area PXA-B, a green light-emitting area PXA-G, and a red light-emitting area PXA-R that are distinguishable from each other.

[0102] The display panel DP may include a plurality of light-emitting elements ED-1, ED-2, and ED-3 that 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 of the light-emitting elements ED-1, ED-2, and ED-3 may emit light in a different wavelength region from the remaining light-emitting elements of the light-emitting elements ED-1, ED-2, and ED-3.

[0103] In the display device DD, according to an embodiment, as Figure 3 and Figure 4AAs shown, the light-emitting regions PXA-B, PXA-G, and PXA-R may have different areas or shapes from each other according to the colors of light emitted from the light-emitting 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 embodiments are not limited thereto, and the light-emitting regions PXA-B, PXA-G, and PXA-R may also emit light of colors other than red, green, and blue light. In an embodiment, the light-emitting regions PXA-B, PXA-G, and PXA-R may have the same area, or the light-emitting regions PXA-B, PXA-G, and PXA-R may be provided with an area ratio different from that Figure 3 shown therein.

[0104] 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 that is disposed between adjacent light-emitting regions PXA-B, PXA-G, and PXA-R and may correspond to the pixel-defining film PDL. In an embodiment, the light-emitting regions PXA-B, PXA-G, and PXA-R may each correspond to a pixel PX (see Figure 1 ).

[0105] The pixel-defining film PDL may define the light-emitting regions PXA-B, PXA-G, and PXA-R. The light-emitting regions PXA-B, PXA-G, and PXA-R may be separated from the peripheral region NPXA by the pixel-defining film PDL.

[0106] The blue light-emitting region PXA-B and the red light-emitting region PXA-R may be alternately arranged along a first direction axis DR1 to form a first group PXG1. The green light-emitting region PXA-G may be arranged along the first direction axis DR1 to form a second group PXG2. The first group PXG1 may be separately arranged from the second group PXG2 along a second direction axis DR2. The first group PXG1 and the second group PXG2 may each be provided in a repeating pattern. The first group PXG1 and the second group PXG2 may be alternately arranged along the second direction axis DR2.

[0107] The red light-emitting region PXA-R can be arranged separately from the green light-emitting region PXA-G along the fourth direction axis DR4. The blue light-emitting region PXA-B can be arranged separately from the green light-emitting region PXA-G along the fifth direction axis DR5. The fourth direction axis DR4 can be a direction between the first direction axis DR1 and the second direction axis DR2. The fifth direction axis DR5 can intersect the fourth direction axis DR4 and can be a direction inclined with respect to the second direction axis DR2, that is, a direction between the opposite direction of the second direction axis DR2 and the first direction axis DR1.

[0108] In an embodiment, the arrangement of the light-emitting regions PXA-B, PXA-G, and PXA-R is not limited to Figure 3 the arrangement shown in. For example, in an embodiment, the red light-emitting region PXA-R, the green light-emitting region PXA-G, and the blue light-emitting region PXA-B can be arranged in this order along the first direction axis DR1 as a repeating sequence. In an embodiment, the shape of each of the light-emitting regions PXA-B, PXA-G, and PXA-R in the plan view is not limited to the shape shown in the drawings and can be defined as a shape different from the shape shown in the figures.

[0109] In a display device DD (such as, for example, as Figure 4A shown in), the substrate layer BS can have a single-layer structure or a multi-layer structure. In an embodiment, the substrate layer BS can include a first synthetic resin layer, an intermediate layer having a single-layer structure or a multi-layer structure, and a second synthetic resin layer stacked in sequence. The intermediate layer can be referred to as a substrate barrier layer. The intermediate layer can include a silicon oxide (SiO x ) layer and an amorphous silicon (a-Si) layer provided on the silicon oxide layer, but the embodiment is not limited thereto. For example, the intermediate layer can include at least one of a silicon oxide layer, a silicon nitride layer, a silicon oxynitride layer, and an amorphous silicon layer.

[0110] The first synthetic resin layer and the second synthetic resin layer can each include a polyimide-based resin. In an embodiment, the first synthetic resin layer and the second synthetic resin layer can each independently include at least one of an acrylate-based resin, a methacrylate-based resin, a polyisoprene-based resin, an ethylene-based resin, an epoxy-based resin, a polyurethane-based resin, a cellulose-based resin, a siloxane-based resin, a polyamide-based resin, and a perylene-based resin. In the specification, the term "X-based resin" refers to a resin including the "X" functional group.

[0111] The circuit layer DP-CL can be disposed on the substrate layer BS, and the circuit layer DP-CL can include a plurality of transistors (not shown). Each of the plurality of transistors (not shown) can include a control electrode, an input electrode, and an output electrode. For example, the circuit layer DP-CL can include switching transistors and driving transistors for driving light-emitting elements ED-1, ED-2, and ED-3 of the display element layer DP-EL.

[0112] The display element layer DP-EL can include a pixel definition film PDL, and a first light-emitting element ED-1, a second light-emitting element ED-2, and a third light-emitting element ED-3. The pixel definition film PDL can have an opening OH defined therein. The first light-emitting element ED-1, the second light-emitting element ED-2, and the third light-emitting element ED-3 can be separated by the pixel definition film PDL. The light-emitting layers EML-B, EML-G, and EML-R of the first light-emitting element ED-1, the second light-emitting element ED-2, and the third light-emitting element ED-3 can be respectively disposed separately in the opening OH defined by the pixel definition film PDL.

[0113] The pixel definition film PDL can be formed of a polymer resin. For example, the pixel definition film PDL can include a polyacrylate resin or a polyimide resin. In an embodiment, the pixel definition film PDL can include an inorganic material other than the polymer resin. The pixel definition film PDL can be formed by including a light-absorbing material, for example, by including a black dye or a black pigment. The pixel definition film PDL containing the black dye or the black pigment can be implemented as a black pixel definition film. When forming the pixel definition film PDL, carbon black or the like can be used as the black dye or the black pigment, but the embodiment is not limited thereto.

[0114] In an embodiment, the pixel definition film PDL can be formed of an inorganic material. For example, the pixel definition film PDL can include an inorganic material such as silicon nitride (SiN x ), silicon oxide (SiO x ), or silicon oxynitride (SiO x N y ).

[0115] The light-emitting elements ED-1, ED-2, and ED-3 may each include a first electrode EL1, a light-emitting layer EML-B, EML-G, or EML-R disposed on the first electrode EL1, a second electrode EL2 disposed on the light-emitting layer EML-B, EML-G, or EML-R, a hole transport region HTR-1, HTR-2, or HTR-3 disposed between the first electrode EL1 and the second electrode EL2, and an electron transport region ETR-1, ETR-2, or ETR-3 disposed between the first electrode EL1 and the second electrode EL2. The light-emitting layers EML-B, EML-G, and EML-R may be respectively disposed between the electron transport regions ETR-1, ETR-2, or ETR-3 and the hole transport regions HTR-1, HTR-2, or HTR-3.

[0116] Referring to Figure 4A , the light-emitting elements ED-1, ED-2, and ED-3 may each include a first electrode EL1, an electron transport region ETR-1, ETR-2, or ETR-3 disposed on the first electrode EL1, a light-emitting layer EML-B, EML-G, or EML-R disposed on the electron transport region ETR-1, ETR-2, or ETR-3, a hole transport region HTR-1, HTR-2, or HTR-3 disposed on the light-emitting layer EML-B, EML-G, or EML-R, and a second electrode EL2 disposed on the hole transport region HTR-1, HTR-2, or HTR-3. The electron transport regions ETR-1, ETR-2, or ETR-3 may be disposed between the first electrode EL1 and the light-emitting layer EML-B, EML-G, or EML-R, and the hole transport regions HTR-1, HTR-2, or HTR-3 may be disposed between the light-emitting layer EML-B, EML-G, or EML-R and the second electrode EL2.

[0117] At least a part of the first electrode EL1 may be exposed in the opening OH of the pixel defining film PDL. The first electrode EL1 may have conductivity. The first electrode EL1 may be formed of a metal material, a metal alloy, a conductive compound, or the like. The first electrode EL1 may be a cathode or an anode. However, the embodiments are not limited thereto. In the embodiments, the first electrode EL1 may be a pixel electrode. The first electrode EL1 may be a transmissive electrode, a semi-transmissive and semi-reflective electrode, or a reflective electrode. The first electrode EL1 may include at least one of Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF, Mo, Ti, W, In, Sn, Zn, their oxides, their compounds, and their mixtures.

[0118] If the first electrode EL1 is a transmissive electrode, the first electrode EL1 may include a transparent metal oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), etc. 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, W, their compounds, or their mixtures (e.g., a mixture of Ag and Mg), or a material having a multilayer structure such as LiF / Ca (a stacked structure of LiF and Ca), LiF / Al (a stacked structure of LiF and Al). In an embodiment, the first electrode EL1 may have a multilayer structure including a reflective film or a semi-transmissive and semi-reflective film formed of the above-mentioned materials, and a transparent conductive film formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), etc. For example, the first electrode EL1 may have a three-layer structure of ITO / Ag / ITO, but the embodiment is not limited thereto. In an embodiment, the first electrode EL1 may include the above-mentioned metal materials, a combination of at least two metal materials selected from the above-mentioned metal materials, or oxides of the above-mentioned metal materials, etc. The first electrode EL1 may have a thickness in the range of about to about . For example, the thickness of the first electrode EL1 may be in the range of about to about .

[0119] The second electrode EL2 may be a common electrode. The second electrode EL2 may be an anode or a cathode, but the embodiment is not limited thereto. For example, when the first electrode EL1 is an anode, the second electrode EL2 may be a cathode; when the first electrode EL1 is a cathode, the second electrode EL2 may be an anode. The second electrode EL2 may include at least one of Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF, Mo, Ti, W, In, Sn, Zn, their oxides, their compounds, or their mixtures.

[0120] The second electrode EL2 may be a transmissive electrode, a semi-transmissive and semi-reflective electrode, or a reflective electrode. When the second electrode EL2 is a transmissive electrode, the second electrode EL2 may be formed of a transparent metal oxide (e.g., indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO)), etc.

[0121] When the second electrode EL2 is a semi-transmissive 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, Yb, W, compounds thereof, or mixtures thereof (e.g., AgMg, AgYb, or MgYb), or materials 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 film or a semi-transmissive semi-reflective film formed of the above materials, and a transparent conductive film formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), etc. For example, the second electrode EL2 may include the above metal materials, a combination of at least two metal materials selected from the above metal materials, or oxides of the above metal materials, etc.

[0122] Although not shown in the drawings, the second electrode EL2 may be electrically connected to an auxiliary electrode. If the second electrode EL2 is electrically connected to the auxiliary electrode, the resistance of the second electrode EL2 can be reduced.

[0123] The light-emitting layers EML-B, EML-G, or EML-R may be respectively disposed between the first electrode EL1 and the second electrode EL2. The first light-emitting element ED-1 may include a first light-emitting layer EML-B, the second light-emitting element ED-2 may include a second light-emitting layer EML-G, and the third light-emitting element ED-3 may include a third light-emitting layer EML-R. The first light-emitting layer EML-B may include a first quantum dot QD-C1. The second light-emitting layer EML-G may include a second quantum dot QD-C2. The third light-emitting layer EML-R may include a third quantum dot QD-C3.

[0124] The quantum dots QD-C1, QD-C2, and QD-C3 respectively included in the light-emitting layers EML-B, EML-G, and EML-R may be stacked to form at least one layer. Figure 4A The quantum dots QD-C1, QD-C2, and QD-C3 having a circular cross-section are shown and may be arranged to form approximately two layers, but the embodiment is not limited thereto. For example, the arrangement of the quantum dots QD-C1, QD-C2, and QD-C3 may vary according to the thickness of the light-emitting layers EML-B, EML-G, and EML-R, the shape of the quantum dots QD-C1, QD-C2, and QD-C3 included in the light-emitting layers EML-B, EML-G, and EML-R, and the average diameter of the quantum dots QD-C1, QD-C2, and QD-C3, etc. In an embodiment, in the light-emitting layers EML-B, EML-G, and EML-R, the quantum dots QD-C1, QD-C2, and QD-C3 may be aligned adjacent to each other to form one layer, or aligned to form multiple layers (such as two or three layers).

[0125] The first quantum dot QD-C1 of the first light-emitting element ED-1 can emit blue light. The second quantum dot QD-C2 of the second light-emitting element ED-2 can emit green light. The third quantum dot QD-C3 of the third light-emitting element ED-3 can emit red light. The quantum dots QD-C1, QD-C2, and QD-C3 can each include a core (not shown) and a shell (not shown) surrounding the core. Thus, the quantum dots QD-C1, QD-C2, and QD-C3 can each have a core-shell structure. In an embodiment, the cores of the quantum dots QD-C1, QD-C2, and QD-C3 can include different materials. In another embodiment, the cores of the quantum dots QD-C1, QD-C2, and QD-C3 can include the same material. Any two of the cores of the quantum dots QD-C1, QD-C2, and QD-C3 can include the same material, and the remaining core can include a different material.

[0126] Figure 4A It is shown that the diameters of the first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 can be similar to each other, but the embodiment is not limited thereto. The diameters of the first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 can be different from each other. For example, the first quantum dot QD-C1 of the first light-emitting element ED-1 that emits light in a shorter wavelength region can have an average diameter smaller than the average diameters of the second quantum dot QD-C2 of the second light-emitting element ED-2 and the third quantum dot QD-C3 of the third light-emitting element ED-3 that each emit light in a longer wavelength region. In the specification, the average diameter can be the arithmetic mean of the particle diameters of a plurality of quantum dots. In the specification, the particle diameter of a quantum dot can be the average of the widths of the quantum dot particles measured on its cross-section.

[0127] The electron transport regions ETR-1, ETR-2, or ETR-3 can each be disposed between the first electrode EL1 and the light-emitting layers EML-B, EML-G, or EML-R. In an embodiment, the electron transport regions ETR-1, ETR-2, or ETR-3 can each include metal nanoparticles NP (see Figure 6 ), which will be described later. In an embodiment, the metal nanoparticles NP (see Figure 6 ) can include a core MC (see Figure 6 ) and a ligand LD (see Figure 6 ) bonded to the core MC (see Figure 6 ). The core MC (see Figure 6 ) can include a metal oxide, and the ligand LD (see Figure 6 ) including an ionic compound derived from bisulfite can include bisulfite. The metal nanoparticles NP including bisulfite (see Figure 6) can improve the luminous efficiency of the light-emitting elements ED-1, ED-2, or ED-3. The metal nanoparticles NP (see Figures 5A to 5D ) will be described in detail below.

[0128] 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 can be respectively disposed in the openings OH so as to be separated from each other. The first light-emitting element ED-1 can include a first electron transport region ETR-1, the second light-emitting element ED-2 can include a second electron transport region ETR-2, and the third light-emitting element ED-3 can include a third electron transport region ETR-3.

[0129] The first electron transport region ETR-1, the second electron transport region ETR-2, and the third electron transport region ETR-3 can each independently have a structure composed of a layer made of a single material, a structure composed of layers including different materials, or a structure including multiple layers containing different materials. The first electron transport region ETR-1, the second electron transport region ETR-2, and the third electron transport region ETR-3 can each independently have a thickness, for example, in the range of about to about .

[0130] In an embodiment, the first electron transport region ETR-1, the second electron transport region ETR-2, and the third electron transport region ETR-3 may each further include an electron injection material and / or an electron transport material of the related art. For example, the first electron transport region ETR-1, the second electron transport region ETR-2, and the third electron transport region ETR-3 may each independently include an anthracene compound. For another example, the first electron transport region ETR-1, the second electron transport region ETR-2, and the third electron transport region ETR-3 may each independently include Alq3 (aluminum tris(8-hydroxyquinoline)), 1,3,5-tris[(3-pyridyl)-benzene-3-yl]benzene, 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzimidazol-1-yl)phenyl)-9,10-dinaphthylanthracene, TPBi (1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene), BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), Bphen (4,7-diphenyl-1,10-phenanthroline), TAZ (3-(4-biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole), NTAZ (4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole), tBu-PBD (2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole), BAlq (bis(2-methyl-8-quinolinyl-N1,O8)-(1,1'-biphenyl-4-ol)aluminum), Bebq2 (bis(10-hydroxybenzoquinoline)beryllium), ADN (9,10-di(naphthalen-2-yl)anthracene), BmPyPhB (1,3-bis[3,5-bis(pyridin-3-yl)phenyl]benzene), and any mixture thereof. For another example, the first electron transport region ETR-1, the second electron transport region ETR-2, and the third electron transport region ETR-3 may each independently include BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), TSPO1 (diphenyl(4-(triphenylsilyl)phenyl)phosphine oxide), Bphen (4,7-diphenyl-1,10-phenanthroline), etc.

[0131] The hole transport regions HTR-1, HTR-2, or HTR-3 can each be disposed between the light-emitting layers EML-B, EML-G, or EML-R and the second electrode EL2. The hole transport regions HTR-1, HTR-2, and HTR-3 of the first light-emitting element ED-1, the second light-emitting element ED-2, and the third light-emitting element ED-3 can be respectively arranged in the plurality of openings OH to be separated. The first light-emitting element ED-1 can include a first hole transport region HTR-1, the second light-emitting element ED-2 can include a second hole transport region HTR-2, and the third light-emitting element ED-3 can include a third hole transport region HTR-3. In an embodiment, the hole transport regions HTR-1, HTR-2, and HTR-3 can include an organic material.

[0132] The hole transport regions HTR-1, HTR-2, and HTR-3 can each independently have a structure composed of a layer made of a single material, a structure composed of layers including different materials, or a structure including multiple layers containing different materials. The first hole transport region HTR-1, the second hole transport region HTR-2, and the third hole transport region HTR-3 can each independently have, for example, a thickness in the range of about to about . For example, the first hole transport region HTR-1, the second hole transport region HTR-2, and the third hole transport region HTR-3 can each independently have a thickness in the range of about to about . For example, the first hole transport region HTR-1, the second hole transport region HTR-2, and the third hole transport region HTR-3 can each independently have a thickness in the range of about to about .

[0133] In an embodiment, the first hole transport region HTR-1, the second hole transport region HTR-2, and the third hole transport region HTR-3 can each include a hole injection material and / or a hole transport material of the related art. For example, the first hole transport region HTR-1, the second hole transport region HTR-2, and the third hole transport region HTR-3 can each independently include a phthalocyanine compound (such as copper phthalocyanine), and include DNTPD (N 1 ,N 1 '-([1,1'-biphenyl]-4,4'-diyl)bis(N 1 -phenyl-N 4 ,N 4-m - xylylenediamine), m - MTDATA (4,4',4” - [tris(3 - methylphenyl)phenylamino]triphenylamine), TDATA (4,4',4” - tris(N,N - diphenylamino)triphenylamine), 2 - TNATA (4,4',4” - tris[N - (2 - naphthyl) - N - phenylamino] - triphenylamine), PEDOT / PSS (poly(3,4 - ethylenedioxythiophene) / poly(4 - styrenesulfonic acid)), PANI / DBSA (polyaniline / dodecylbenzenesulfonic acid), PANI / CSA (polyaniline / camphorsulfonic acid), PANI / PSS (polyaniline / poly(4 - styrenesulfonic acid)), NPB (N,N' - bis(naphthalen - 1 - yl) - N,N' - diphenylbenzidine), triphenylamine - containing polyether ketone (TPAPEK), 4 - isopropyl - 4' - methyldiphenyliodonium [tetrakis(pentafluorophenyl)borate], and HAT - CN (dipyrazino[2,3 - f:2',3' - h]quinoxaline - 2,3,6,7,10,11 - hexanitrile), etc.

[0134] In the examples, the first hole - transporting region HTR - 1, the second hole - transporting region HTR - 2, and the third hole - transporting region HTR - 3 may each independently include carbazole derivatives (such as N - phenylcarbazole and polyvinylcarbazole), fluorene derivatives, triphenylamine derivatives (such as (TPD (N,N' - bis(3 - methylphenyl) - N,N' - diphenyl - [1,1' - biphenyl] - 4,4' - diamine) and TCTA (4,4',4” - tris(N - carbazolyl)triphenylamine)), NPB (N,N' - bis(naphthalen - 1 - yl) - N,N' - dibenzidine), TAPC (4,4' - cyclohexylidenebis[N,N - bis(4 - methylphenyl)aniline]), HMTPD (4,4' - bis[N,N' - (3 - tolyl)amino] - 3,3' - dimethylbiphenyl), CzSi (9 - (4 - tert - butylphenyl) - 3,6 - bis(triphenylsilyl) - 9H - carbazole), CCP (9 - phenyl - 9H - 3,9' - bicarbazole), mCP (1,3 - bis(N - carbazolyl)benzene), or mDCP (1,3 - bis(1,8 - dimethyl - 9H - carbazol - 9 - yl)benzene), etc.

[0135] The encapsulation layer TFE may include at least one inorganic film (hereinafter, inorganic encapsulation film). In the examples, the encapsulation layer TFE may include at least one organic film (hereinafter, organic encapsulation film) and at least one inorganic encapsulation film.

[0136] The inorganic encapsulation film can protect the display element layer DP-EL from moisture and / or oxygen, and the organic encapsulation film can protect the display element layer DP-EL from foreign substances such as dust particles. The inorganic encapsulation film can include silicon nitride, silicon oxynitride, silicon oxide, titanium oxide, aluminum oxide, etc., but the embodiments are not limited thereto. The organic encapsulation film can include acrylate compounds, epoxy compounds, etc. The organic encapsulation film can include a photopolymerizable organic material, but the embodiments are not limited thereto.

[0137] The optical layer PP can include a substrate base BL and a color filter layer CFL. The substrate base BL can provide a substrate surface on which the color filter layer CFL is disposed. The substrate base BL can be a glass substrate, a metal substrate, or a plastic substrate. However, the embodiments are not limited thereto, and the substrate base BL can include an inorganic layer, an organic layer, or a composite material layer.

[0138] The color filter layer CFL can include a first color filter CF-B, a second color filter CF-G, and a third color filter CF-R. The first color filter CF-B, the second color filter CF-G, and the third color filter CF-R can correspond to a first light-emitting element ED-1, a second light-emitting element ED-2, and a third light-emitting element ED-3, respectively. For example, the first color filter CF-B can be a blue color filter, the second color filter CF-G can be a green color filter, and the third color filter CF-R can be a red color filter. The first color filter CF-B, the second color filter CF-G, and the third color filter CF-R can correspond to a first light-emitting region PXA-B, a second light-emitting region PXA-G, and a third light-emitting region PXA-R, respectively.

[0139] The first color filter CF-B, the second color filter CF-G, and the third color filter CF-R can each include a polymer photosensitive resin and a pigment or a dye. The first color filter CF-B can include a blue pigment or a blue dye, the second color filter CF-G can include a green pigment or a green dye, and the third color filter CF-R can include a red pigment or a red dye. However, the embodiments are not limited thereto, and the first color filter CF-B may not include a pigment or a dye. The first color filter CF-B can include a polymer photosensitive resin and may not include a pigment or a dye. The first color filter CF-B can be transparent. The first color filter CF-B can be formed of a transparent photosensitive resin.

[0140] The color filter layer CFL can further include a buffer layer BFL. For example, the buffer layer BFL can 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 can be an inorganic material layer including at least one of silicon nitride, silicon oxide, and silicon oxynitride. The buffer layer BFL can be formed of a single layer or multiple layers.

[0141] In an embodiment, the second color filter CF-G and the third color filter CF-R may each be a yellow color filter. The second color filter CF-G and the third color filter CF-R may not be separated and may be provided as an integral color filter.

[0142] Although not shown in the figures, the color filter layer CFL may further include a light-blocking portion (not shown). The light-blocking portion (not shown) may be a black matrix. The light-blocking portion may include an organic light-blocking material or an inorganic light-blocking material each containing a black pigment or a black dye. The light-blocking portion (not shown) may prevent light leakage and may set boundaries between adjacent color filters CF-B, CF-G, and CF-R.

[0143] Figure 4B is a schematic cross-sectional view of a display device DD-1 according to another embodiment. In Figure 4B the description of, features that have already been described for Figures 1 to 4A will not be explained again, and different features will be described.

[0144] Compared with Figure 4A the display device DD in, Figure 4B the display device DD-1 in is different at least in that the positions of the electron transport regions ETR-1, ETR-2, and ETR-3 and the hole transport regions HTR-1, HTR-2, and HTR-3 may be different. Referring to Figure 4B , each of the light-emitting elements ED-1, ED-2, and ED-3 may include a first electrode EL1, a hole transport region HTR-1, HTR-2, or HTR-3 provided on the first electrode EL1, a light-emitting layer EML-B, EML-G, or EML-R provided on the hole transport region HTR-1, HTR-2, or HTR-3, an electron transport region ETR-1, ETR-2, or ETR-3 provided on the light-emitting layer EML-B, EML-G, or EML-R, and a second electrode EL2 provided on the electron transport region ETR-1, ETR-2, or ETR-3. The electron transport regions ETR-1, ETR-2, or ETR-3 may be provided between the light-emitting layer EML-B, EML-G, or EML-R and the second electrode EL2, and the hole transport regions HTR-1, HTR-2, or HTR-3 may be provided between the first electrode EL1 and the light-emitting layer EML-B, EML-G, or EML-R.

[0145] Figures 5A to 5D are schematic cross-sectional views of light-emitting elements ED, ED-a, ED-b, and ED-c according to embodiments. Referring to Figures 5A to 5D, the light-emitting elements ED, ED-a, ED-b, and ED-c may each include a first electrode EL1, a light-emitting layer EML disposed on the first electrode EL1, a second electrode EL2 disposed on the light-emitting layer EML, a hole transport region HTR disposed between the first electrode EL1 and the second electrode EL2, and an electron transport region ETR disposed between the first electrode EL1 and the second electrode EL2. The electron transport region ETR may be separated from the hole transport region HTR, and the light-emitting layer EML is located between the electron transport region ETR and the hole transport region HTR.

[0146] Figure 4A 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 Figure 5A and Figure 5B may each independently have a structure according to the light-emitting elements ED and ED-a as described with reference to Figure 4B 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 Figure 5C and Figure 5D may each independently have a structure according to the light-emitting elements ED-b and ED-c as described with reference to

[0147] Referring to Figure 5A and Figure 5B , the light-emitting elements ED and ED-a may each include a first electrode EL1, an electron transport region ETR, a light-emitting layer EML, a hole transport region HTR, and a second electrode EL2 stacked in sequence. In the light-emitting elements ED and ED-a, the electron transport region ETR may include metal nanoparticles NP according to an embodiment.

[0148] Referring to Figure 5A , the hole transport region HTR may include a hole injection layer HIL and a hole transport layer HTL. The hole transport layer HTL may be disposed on the light-emitting layer EML, and the hole injection layer HIL may be disposed on the hole transport layer HTL. The electron transport region ETR may include an electron injection layer EIL and an electron transport layer ETL. The electron injection layer EIL may be disposed on the first electrode EL1, the electron transport layer ETL may be disposed on the electron injection layer EIL, and the light-emitting layer EML may be disposed on the electron transport layer ETL. Although not shown in the drawings, in an embodiment, the electron injection layer EIL may be omitted.

[0149] Figure 5B The light-emitting element ED-a in Figure 5AThe light-emitting element ED therein may differ at least in that the hole transport region HTR may further include an electron blocking layer EBL, and the electron transport region ETR may further include a hole blocking layer HBL. The electron blocking layer EBL may be disposed on the light-emitting layer EML. The electron blocking layer EBL may be disposed between the light-emitting layer EML and the hole transport layer HTL. The hole blocking layer HBL may be disposed on the electron transport layer ETL. The hole blocking layer HBL may be disposed between the light-emitting layer EML and the electron transport layer ETL. Although not shown in the drawings, in an embodiment, either the electron blocking layer EBL or the hole blocking layer HBL may be omitted.

[0150] Figure 5C and Figure 5D the light-emitting elements ED-b and ED-c shown in Figure 5A and Figure 5B the light-emitting elements ED and ED-a shown in may differ at least in that the positions of the hole transport region HTR and the electron transport region ETR may be different. Referring to Figure 5C and Figure 5D , the light-emitting elements ED-b and ED-c may each include a first electrode EL1, a hole transport region HTR, a light-emitting layer EML, an electron transport region ETR, and a second electrode EL2 stacked in sequence. In the light-emitting element ED-b or ED-c, the electron transport region ETR may include metal nanoparticles NP according to an embodiment.

[0151] Referring to Figure 5C , the hole transport region HTR may include a hole injection layer HIL and a hole transport layer HTL. The hole injection layer HIL may be disposed on the first electrode EL1, and the hole transport layer HTL may be disposed on the hole injection layer HIL. The electron transport region ETR may include an electron injection layer EIL and an electron transport layer ETL. The electron transport layer ETL may be disposed on the light-emitting layer EML, and the electron injection layer EIL may be disposed on the electron transport layer ETL. Although not shown in the drawings, in an embodiment, the electron injection layer EIL may be omitted.

[0152] Referring to Figure 5D , the hole transport region HTR may further include an electron blocking layer EBL, and the electron transport region ETR may further include a hole blocking layer HBL. The electron blocking layer EBL may be disposed between the hole transport layer HTL and the light-emitting layer EML. The hole blocking layer HBL may be disposed between the light-emitting layer EML and the electron transport layer ETL.

[0153] Referring to Figures 5A to 5D, the electron transport region ETR may include metal nanoparticles NP according to an embodiment. At least one of the electron injection layer EIL, the electron transport layer ETL, and the hole blocking layer HBL may each independently include metal nanoparticles NP according to an embodiment. For example, the electron transport layer ETL may include metal nanoparticles NP according to an embodiment. In an embodiment, at least one of the hole blocking layer HBL and the electron injection layer EIL may each independently include metal nanoparticles NP according to an embodiment. In another embodiment, the hole blocking layer HBL, the electron transport layer ETL, and the electron injection layer EIL may each independently include metal nanoparticles NP according to an embodiment. The electron transport region ETR including metal nanoparticles NP according to an embodiment may maintain excellent electron injection and / or electron transport characteristics, and may also reduce or prevent charge imbalance, thereby contributing to improving the light emission efficiency of the light emitting elements ED, ED-a, ED-b, and ED-c. The metal nanoparticles NP according to an embodiment will be described in detail later.

[0154] The light emitting layer EML may include quantum dots QD-C. The first quantum dots QD-C1, the second quantum dots QD-C2, and the third quantum dots QD-C3 as shown in Figure 4A and Figure 4B may be the same as or substantially similar to the quantum dots QD-C explained in the following description. The quantum dots QD-C may not include cadmium.

[0155] In the specification, the quantum dots QD-C may be crystals of semiconductor compounds. The quantum dots QD-C may emit light at various emission wavelengths according to the size of the crystals. For example, the diameter of the quantum dots QD-C may be in the range of about 1 nm to about 10 nm.

[0156] The quantum dots QD-C may be synthesized by a wet chemical process, a metal organic chemical vapor deposition process, a molecular beam epitaxy process, or similar processes thereof. In the wet chemical process, an organic solvent and a precursor material are mixed, and particulate crystals of the quantum dots QD-C are grown. When the crystals grow, the organic solvent may coordinate as a dispersant on the crystal surface of the quantum dots QD-C, and the growth of the crystals may be controlled. Therefore, the wet chemical process may control the growth of the quantum dots QD-C particles by a process that is easier to perform and less costly than vapor deposition methods such as metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE).

[0157] In an embodiment, the quantum dot QD-C may include a II-VI group semiconductor compound, a I-II-VI group semiconductor compound, a II-IV-VI group semiconductor compound, a I-II-IV-VI group semiconductor compound, a III-V group semiconductor compound, a III-VI group semiconductor compound, a I-III-VI group semiconductor compound, a IV-VI group semiconductor compound, a II-IV-V group semiconductor compound, a Group IV element or compound, or any combination thereof. In the specification, the term "group" refers to the groups in the Periodic Table of the International Union of Pure and Applied Chemistry (IUPAC).

[0158] Examples of II-VI group semiconductor compounds may include: binary compounds such as ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, and MgS; ternary compounds such as ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, and MgZnS; quaternary compounds such as HgZnSeS, HgZnSeTe, and HgZnSTe; and any combination thereof.

[0159] In an embodiment, the II-VI group semiconductor compound may further include a Group I element and / or a Group IV element. Examples of I-II-VI group semiconductor compounds may include CuZnS, etc. Examples of II-IV-VI group semiconductor compounds may include ZnSnS, etc. Examples of I-II-IV-VI group semiconductor compounds may include quaternary compounds selected from the group consisting of Cu2ZnSnS2, Cu2ZnSnS4, Cu2ZnSnSe4, Ag2ZnSnS2, and any combination thereof.

[0160] Examples of III-V semiconductor compounds may include: binary compounds such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, and InSb; ternary compounds such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InNP, InAlP, InNAs, InNSb, InPAs, and InPSb; quaternary compounds such as GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb; and any combination thereof. In an embodiment, the III-V semiconductor compound may further include a Group II element. Examples of III-V semiconductor compounds further including a Group II element may include InZnP, InGaZnP, InAlZnP, etc.

[0161] Examples of III-VI semiconductor compounds may include: binary compounds such as GaS, Ga2S3, GaSe, Ga2Se3, GaTe, InS, InSe, In2Se3, and InTe; ternary compounds such as InGaS3 and InGaSe3; and any combination thereof.

[0162] Examples of I-III-VI semiconductors may include: ternary compounds such as AgInS, AgInS2, AgInSe2, AgGaS, AgGaS2, AgGaSe2, CuInS, CuInS2, CuInSe2, CuGaS2, CuGaSe2, CuGaO2, AgGaO2, and AgAlO2; quaternary compounds such as AgInGaS2 and AgInGaSe2; and any combination thereof.

[0163] Examples of IV-VI semiconductor compounds may include: binary compounds such as SnS, SnSe, SnTe, PbS, PbSe, and PbTe; ternary compounds such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, and SnPbTe; quaternary compounds such as SnPbSSe, SnPbSeTe, and SnPbSTe; and any combination thereof.

[0164] Examples of II-IV-V group semiconductor compounds may include ternary compounds such as ZnSnP, ZnSnP2, ZnSnAs2, ZnGeP2, ZnGeAs2, and any combination thereof.

[0165] Examples of group-IV elements or compounds may include: single-element materials such as Si and Ge; binary compounds such as SiC and SiGe; and any combination thereof.

[0166] Each element included in a compound (such as a binary compound, ternary compound, or quaternary compound) may be present in the particles in a uniform or non-uniform concentration. For example, the formula may indicate the elements included in the compound, but the elemental ratios in the compound may be different. For example, AgInGaS2 may represent AgIn x Ga 1-x S2 (where x is a real number between 0 and 1).

[0167] In an embodiment, the quantum dot QD-C may have a single structure in which each element included in the corresponding quantum dot QD-C has a uniform concentration, or the quantum dot QD-C may have a core-shell structure. For example, the material included in the core and the material included in the shell may be different from each other.

[0168] The shell of the quantum dot QD-C may serve as a protective layer for maintaining semiconductor properties by preventing chemical denaturation of the core, and / or as a charging layer for imparting electrophoretic properties to the quantum dot. The shell may be a single layer or multiple layers. The quantum dot having a core-shell structure may have a concentration gradient in which the elemental concentration present in the shell decreases toward the core.

[0169] Examples of the shell of the quantum dot QD-C can include metal oxides, non-metal oxides, semiconductor compounds, and any combination thereof. Examples of the metal oxide or non-metal oxide can include: binary compounds such as SiO2, Al2O3, TiO2, ZnO, MnO, Mn2O3, Mn3O4, CuO, FeO, Fe2O3, Fe3O4, CoO, Co3O4, and NiO; ternary compounds such as MgAl2O4, CoFe2O4, NiFe2O4, and CoMn2O4; and any combination thereof. Examples of the semiconductor compound can include: II-VI group semiconductor compounds as described in the specification; III-V group semiconductor compounds; III-VI group semiconductor compounds; I-III-VI group semiconductor compounds; IV-VI group semiconductor compounds; and any combination thereof. For example, the semiconductor compound can include ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaS, GaSe, AgGaS, AgGaS2, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, or a combination thereof.

[0170] The quantum dot QD-C can have a full width at half maximum (FWHM) of the emission spectrum less than or equal to about 45 nm. For example, the quantum dot QD-C can have an FWHM of the emission spectrum less than or equal to about 40 nm. For example, the quantum dot QD-C can have an FWHM of the emission spectrum less than or equal to about 30 nm. When the FWHM of the quantum dot QD-C is within any of the above ranges, color purity or color reproducibility can be improved. The light emitted by the quantum dot QD-C can be emitted in each direction, thereby improving the wide viewing angle. The quantum dot QD-C can have any form or shape used in the related art. For example, the quantum dot QD-C can be formed of nanoparticles, nanotubes, nanowires, nanofibers, nanoplates, etc., or the quantum dot QD-C can be in a circular shape, pyramid shape, multi-arm shape, or cubic shape.

[0171] By controlling the size of the quantum dot QD-C or controlling the elemental ratio in the compound constituting the quantum dot QD-C, the bandgap can be controlled such that the light-emitting layer EML including the quantum dot QD-C can have light in various wavelength ranges. Therefore, by using the above-described quantum dot QD-C (with different sizes or different elemental ratios in the quantum dot compound), light-emitting elements ED, ED-a, ED-b, and ED-c that emit light in different wavelength ranges can be realized. For example, the size of the quantum dot QD-C or the elemental ratio in the compound constituting the quantum dot QD-C can be adjusted to emit red, green, and / or blue light. In an embodiment, the quantum dot QD-C can be configured to emit white light by combining lights of various colors.

[0172] Figure 6 is a schematic cross-sectional view of the metal nanoparticle NP according to an embodiment. In an embodiment, the metal nanoparticle NP may include a core MC and a ligand LD bonded to the core MC. Figure 6 Five ligands LD are shown as an example, but the number of ligands LD is not limited thereto. As Figure 6 shown, the positions where the ligands LD are bonded are only examples, and the embodiment is not limited thereto.

[0173] In an embodiment, the core MC of the metal nanoparticle NP may include a metal oxide. In an embodiment, the metal oxide may include at least one of SnO, SnO2, CuGaO2, Ga2O3, Cu2O, SrCu2O2, SrTiO3, CuAlO2, Ta2O5, NiO, BaSnO3, and TiO2; or the metal oxide may be represented by Formula M-1.

[0174] [Formula M-1]

[0175] Zn (1-q) Me q O

[0176] In Formula M-1, q may be a real number from 0 to 0.5. In Formula M-1, Me may be Li, Be, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Rb, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Sb, or Ba. For example, the core MC of the metal nanoparticle NP may include ZnMgO. However, this is only an example, and the embodiment is not limited thereto.

[0177] In an embodiment, the ligand LD of the metal nanoparticle NP may include a bisulfite derived from an ionic compound represented by Formula A-1. The ionic compound represented by Formula A-1 may include a metal cation and a bisulfite anion.

[0178] [Formula A-1]

[0179]

[0180] In formula A-1, represents an ionic bond. In formula A-1, Mp can be Zn, Li, Be, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Rb, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Sb, or Ba. In formula A-1, Mp n+ (n＝1～7) can correspond to a metal cation, and -OS(=O)OH can correspond to a bisulfite anion.

[0181] Referring to Figure 6 , the ligand LD can include a first ligand LD1 and a second ligand LD2. The ligand LD derived from the ionic compound represented by formula A-1 can include a first ligand LD1 and a second ligand LD2 generated by dissociation of the ionic bond of the ionic compound of formula A-1. The first ligand LD1 can include the bisulfite anion in formula A-1, and the second ligand LD2 can include a metal cation. For example, the second ligand LD2 can include Mp in formula A-1. Although not shown in the drawings, in the examples, the second ligand LD2 can be omitted.

[0182] In the metal nanoparticle NP, the first ligand LD1 and the second ligand LD2 can each be bonded to the surface M_SF of the core MC. Figure 7 is Figure 6 an enlarged schematic view of region XX' of Figure 7 can show the ligand LD bonded to the surface M_SF of the core MC. Figure 7 shows that the core MC can include a metal oxide composed of zinc, magnesium, and oxygen, and the ligand LD can include a sodium cation (Na + ) as the second ligand LD2 and a bisulfite anion as the first ligand LD1.

[0183] On the surface M_SF of the core MC, the metal oxide elements included in the core MC can be exposed. For example, zinc, magnesium, and oxygen can be exposed on the surface M_SF of the core MC, and the ligand LD can be bonded to at least one of zinc and magnesium. In the examples, the ligand LD can also be bonded to oxygen. The first ligand LD1 can be bonded to at least one of zinc and magnesium on the surface M_SF of the core MC. The second ligand LD2 can be bonded to oxygen on the surface M_SF of the core MC.

[0184] The zinc, magnesium, and oxygen exposed on the surface M_SF of the core MC can each include dangling bonds. In Figure 7 , the dangling bonds of zinc, magnesium, and oxygen are respectively represented as Zn D+, Mg D+ and O D- . A dangling bond is an outermost electron that does not participate in bonding, which can correspond to a surface defect of the core MC, and the surface defect of the core MC can be resolved by a ligand LD bonded to the core MC. A first ligand LD1 including a bisulfite anion can bond to at least one of a zinc dangling bond (Zn D+ ) and a magnesium dangling bond (Mg D+ ) on the surface M_SF of the core MC. The oxygen that is bonded to the sulfur atom and carries a negative charge in the bisulfite anion can bond to at least one of the zinc dangling bond (Zn D + ) and the magnesium dangling bond (Mg D+ ). The oxygen that is bonded to the sulfur atom and carries a negative charge in the bisulfite anion can directly bond to the surface M_SF of the core MC. A second ligand LD2 including a sodium ion can bond to an oxygen dangling bond (O D- ) on the surface M_SF of the core MC.

[0185] A metal nanoparticle NP including a bisulfite ion bonded to the core MC can maintain excellent electron injection and excellent electron transport characteristics, and can reduce or prevent charge imbalance in the light-emitting layer EML (see Figures 5A to 5D ). In a light-emitting device of the related art, when the electron transport region includes a metal nanoparticle composed of a core and a ligand and the hole transport region includes an organic material, charge imbalance may occur in the light-emitting layer. Due to excessive electron injection into the light-emitting layer, the auger recombination corresponding to non-light-emitting recombination increases, resulting in a decrease in the light-emitting efficiency of the light-emitting device. Auger recombination corresponds to the recombination of holes and electrons that do not result in light emission, and the energy of the recombination may increase the energy of other holes and / or electrons. In contrast, the metal nanoparticle NP according to the embodiment can include a bisulfite bonded to the core MC, and thus can solve the defect of the core MC and can prevent excessive injection of electrons, thereby improving the light-emitting efficiency of the light-emitting device ED, ED-a, ED-b, or ED-C (see Figures 5A to 5D ).

[0186] In an embodiment, based on 100 mol% of the total number of moles of metal nanoparticles NP, the number of moles of bisulfite can be in the range of about 5 mol% to about 20 mol%. Based on 100 mol% of the total number of moles of metal nanoparticles, when the number of moles of bisulfite is less than or equal to about 5 mol%, the problems of core defects and charge imbalance in the light-emitting layer may not be solved, making it impossible to improve the luminous efficiency of the light-emitting element. Based on 100 mol% of the total number of moles of metal nanoparticles, when the number of moles of bisulfite is greater than or equal to about 20 mol%, bisulfite may be included in excess, and the excess bisulfite may have high insulating properties, resulting in deterioration of the characteristics of the light-emitting element. On the contrary, the metal nanoparticles NP according to the embodiment can include bisulfite in the range of about 5 mol% to about 20 mol% based on 100 mol% of the total number of moles of metal nanoparticles NP, so that the luminous efficiency of the light-emitting element ED, ED-a, ED-b or ED-c (see Figures 5A to 5D ) can be improved.

[0187] Figures 8A to 8C is a graph showing the results of evaluating the light-emitting elements in Experimental Examples 1 to 6. Based on 100 mol% of the total number of moles of metal nanoparticles, the number of moles of bisulfite in Experimental Examples 1 to 6 is different. In Figures 8A to 8C , except for the number of moles of bisulfite, the light-emitting elements in Experimental Examples 1 to 6 can have the same configuration. Figures 8A to 8C The curve diagram of

[0188] shows the results evaluated using a CS-2000A spectrometer of Konica Minolta, Inc., with a Keithley 2400 connected. Figures 8A to 8C In 2 (thickness about ), ITO is patterned on a glass substrate, the glass substrate is cut into a size of about 50 mm × 50 mm × 0.7 mm, and each is ultrasonically cleaned with isopropyl alcohol and pure water for about 5 minutes, and cleaned by ultraviolet (UV) light irradiation for about 30 minutes and exposure to ozone.

[0189] A hole injection layer is formed by depositing poly(ethylenedioxythiophene) / polystyrene sulfonate (PEDOT / PSS) with a thickness of about , and by depositing a thickness of about Poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl))diphenylamine)] (TFB) forms a hole transport layer. ZnSeTe quantum dots are deposited on the hole transport layer to form a light-emitting layer having a thickness of approximately A metal oxide or metal nanoparticles are provided on the light-emitting layer to form an electron transport layer having a thickness of approximately Al is deposited on the electron transport layer to form a second electrode having a thickness of approximately Thereby completing the fabrication of the light-emitting device.

[0190] In Figures 8A to 8C The light-emitting device in Experimental Example 1 was fabricated by providing metal nanoparticles that do not include bisulfite, such that the metal nanoparticles are metal oxides containing ZnMgO. The light-emitting device in Experimental Example 1 includes metal nanoparticles fabricated by providing approximately 10 mmol of ZnMgO and not providing bisulfite (i.e., 0 mol%).

[0191] The light-emitting devices in Experimental Examples 2 to 6 were fabricated by providing metal nanoparticles that include bisulfite, and the metal nanoparticles have a metal oxide core that includes ZnMgO. The light-emitting devices in Experimental Examples 2 to 6 include metal nanoparticles fabricated by providing approximately 10 mmol of ZnMgO and respectively providing approximately 1 mmol, approximately 5 mmol, approximately 10 mmol, approximately 20 mmol, or approximately 25 mmol of bisulfite. In the light-emitting devices in Experimental Examples 2 to 6, the bisulfite is, for example, sodium bisulfite. For example, the bisulfite is derived from the ionic compound represented by Formula A-1, where Mp is Na.

[0192] In the light-emitting device in Experimental Example 2, approximately 1 mmol (i.e., 1 mol%) of bisulfite was provided; and in the light-emitting device in Experimental Example 3, approximately 5 mmol (i.e., 5 mol%) of bisulfite was provided. In the light-emitting device in Experimental Example 4, approximately 10 mmol (i.e., 10 mol%) of bisulfite was provided; and in the light-emitting device in Experimental Example 5, approximately 20 mmol (i.e., 20 mol%) of bisulfite was provided. In the light-emitting device in Experimental Example 6, approximately 25 mmol (i.e., 25 mol%) of bisulfite was provided. In the light-emitting devices in Examples 3 to 5, based on 100 mol% of the total moles of the metal nanoparticles, the mole number of the bisulfite is in the range of approximately 5 mol% to approximately 20 mol%. For example, the light-emitting devices in Experimental Examples 3 to 5 satisfy the range of the mole number of the bisulfite according to the Examples.

[0193] Figure 8A is a graph showing the results of evaluating the current density (mA / cm 2 ) according to the driving voltage (V) in the light-emitting elements in Experimental Examples 1 to 6. Referring to Figure 8A , it can be seen that, compared with the light-emitting element in Experimental Example 1, the light-emitting elements in Experimental Examples 2 to 5 have good current density according to the driving voltage. It can be seen that the light-emitting element in Experimental Example 6 has a relatively low current density according to the driving voltage. Based on 100 mol% of the total number of moles of metal nanoparticles, the light-emitting element in Experimental Example 6 contains approximately 25 mol% of bisulfite (i.e., the amount of bisulfite used is excessive). Due to the high insulation characteristics of the excessive bisulfite, the light-emitting element in Experimental Example 6 has a low current density.

[0194] Figure 8B is a graph showing the results of evaluating the luminance (cd / m 2 ) according to the current density (mA / cm 2 ) in the light-emitting elements in Experimental Examples 1 to 6. Figure 8C is a graph showing the results of evaluating the external quantum efficiency (EQE, %) according to the current density (mA / cm 2 ) in the light-emitting elements in Experimental Examples 1 to 6. Table 1 shows the Figure 8B maximum luminance (cd / m 2 ) values of Experimental Examples 1 to 6 in Figure 8C and the maximum EQE (%) values of Experimental Examples 1 to 6 in

[0195] [Table 1]

[0196]

[0197]

[0198] Referring to Figure 8B and Table 1, it can be seen that the light-emitting elements in Experimental Examples 1 to 5 have good luminance. Referring to Figure 8C and Table 1, it can be seen that, compared with the light-emitting element in Experimental Example 1, the light-emitting elements in Experimental Examples 3 to 5 have excellent external quantum efficiency. Referring together to Figures 8A to 8CAs can be seen from Table 1, a light-emitting element based on 100 mol% of the total number of moles of metal nanoparticles and including bisulfite in the range of about 5 mol% to about 20 mol% has excellent luminous efficiency while maintaining good current density and luminance. Therefore, in the examples, it can be seen that a light-emitting element based on 100 mol% of the total number of moles of metal nanoparticles and including bisulfite in the range of about 5 mol% to about 20 mol% has excellent luminous efficiency.

[0199] The light-emitting element in Experimental Example 2 includes bisulfite, but based on 100 mol% of the total number of moles of metal nanoparticles, the number of moles of bisulfite is less than or equal to about 5 mol%. Therefore, the light-emitting element in Experimental Example 2 may not have improved external quantum efficiency.

[0200] The light-emitting element in Experimental Example 6 includes bisulfite, but based on 100 mol% of the total number of moles of metal nanoparticles, the number of moles of bisulfite is greater than or equal to about 20 mol%. As described above, the light-emitting element including an excessive amount of bisulfite in Experimental Example 6 has high insulation characteristics, resulting in low luminance and low external quantum efficiency.

[0201] The light-emitting element according to the embodiment can be manufactured by the method for manufacturing a light-emitting element according to the embodiment. Figure 9A and Figure 9B is a flowchart of the method for manufacturing a light-emitting element according to the embodiment. Figures 10 to 11B is a schematic diagram of the steps of manufacturing a light-emitting element according to the embodiment. Hereinafter, for Figures 9A to 11B the description, the features already explained with reference to Figures 1 to 8C will not be explained again, and different features will be described.

[0202] Referring to Figure 9A and Figure 9B , the method for manufacturing a light-emitting element according to the embodiment may include forming a first electrode (S100), forming a light-emitting layer on the first electrode (S300), forming a second electrode on the light-emitting layer (S500), forming a hole transport region (S400 or S250), and forming an electron transport region (S200 or S450).

[0203] In an embodiment, any one of forming the electron transport region (S200 or S450) and forming the hole transport region (S400 or S250) may be performed between the step of forming the first electrode (S100) and the step of forming the light-emitting layer (S300), and the other step of forming the electron transport region (S200 or S450) and forming the hole transport region (S400 or S250) may be performed between the step of forming the light-emitting layer (S300) and the step of forming the second electrode (S500). Figure 9A It shows that the step of forming the electron transport region (S200) is performed between the step of forming the first electrode (S100) and the step of forming the light-emitting layer (S300), and the step of forming the hole transport region (S400) is performed between the step of forming the light-emitting layer (S300) and the step of forming the second electrode (S500). On the contrary, Figure 9B It shows that the step of forming the hole transport region (S250) is performed between the step of forming the first electrode (S100) and the step of forming the light-emitting layer (S300), and the step of forming the electron transport region (S450) is performed between the step of forming the light-emitting layer (S300) and the step of forming the second electrode (S500).

[0204] The method for manufacturing a light-emitting element according to an embodiment may include generating metal nanoparticles NP before the step of forming the electron transport region (S200 or S450). Figure 10 It is a schematic diagram of the step of generating metal nanoparticles NP.

[0205] In an embodiment, the step of generating metal nanoparticles NP may include generating a core MC and providing the ionic compound represented by Formula A-1 as described above to the core MC to thereby generate metal nanoparticles NP. By providing the ionic compound, the ligand LD may bond to the surface M_SF of the core MC. In Figure 10 it, "Step 1" may represent the step of providing the ionic compound represented by Formula A-1.

[0206] In an embodiment, the core MC may include a metal oxide. The step of generating the core MC may include preparing a solution including a first metal precursor having a first metal, a second metal precursor having a second metal, and a first solvent, and providing a second solvent to the solution. The first metal and the second metal may be different from each other. The first metal and the second metal may each independently include Li, Be, Na, Mg, Al, K, Ca, Ta, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Rb, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Zn, Sb, or Ba. In the specification, the metal precursor may be a material including a metal and an element chemically bonded to the metal, and the element chemically bonded to the metal may be an element easily dissociable from the metal. In an embodiment, the metal precursor may be provided in the form of a salt.

[0207] In an embodiment, the core MC may include ZnMgO. The first metal precursor may be a zinc precursor, and the second metal precursor may be a magnesium precursor. The zinc precursor and the magnesium precursor may each independently include an acetate ion or a halogen ion. The halogen ion may include at least one of a fluoride ion, a bromide ion, a chloride ion, and an iodide ion. The acetate ion and the halogen ion may each be chemically bonded to zinc and / or magnesium.

[0208] The first metal precursor and the second metal precursor may each be provided by being dissolved in the first solvent. The first solvent may be a polar solvent. The first solvent may include at least one of ethanol and dimethyl sulfoxide (DMSO). However, this embodiment is not limited thereto, and any solvent may be used as the first solvent without limitation as long as it is a solvent in which the first metal precursor and the second metal precursor can each be easily dissolved.

[0209] The second solvent may be provided to the solution including the first metal precursor, the second metal precursor, and the first solvent. The second solvent may include at least one of potassium hydroxide, sodium hydroxide, trimethylammonium hydroxide (TMAM), and tetramethylammonium hydroxide (TMAH). Ethanol may further be provided while providing the second solvent. Thus, the core MC including the metal oxide can be formed.

[0210] An ionic compound represented by Formula A-1 may be provided to the formed core MC. The surface M_SF of the core MC may be treated with the ionic compound. Thus, the ligand LD may be bonded to the surface M_SF by reacting with zinc, magnesium, and oxygen exposed on the surface M_SF of the core MC. After the ligand LD is bonded to the core MC, the metal nanoparticles NP may be separated from the mixture. The separated metal nanoparticles NP may be dispersed in a third solvent CV (see Figure 12 ) so that those for forming an electron transport region ETR (seeFigures 5A to 5D ) Composition COP (see Figure 12 ).

[0211] Figure 11A It is a schematic diagram of the step of providing composition COP onto the first electrode EL1 to form an electron transport region ETR (see Figure 5A and Figure 5B ). The first electrode EL1 can be formed on the substrate layer BS. For example, the first electrode EL1 can be formed on a circuit layer DP-CL provided on the substrate layer BS. Figure 11B It is a diagram showing the step of providing composition COP onto the light-emitting layer EML. Figure 11B Different from Figure 11A may be at least that: before the step of providing composition COP, the step of forming the light-emitting layer EML is performed.

[0212] In the embodiment of performing the manufacturing steps shown in Figure 11A , the light-emitting elements ED and ED-a shown in Figure 5A and Figure 5B can be manufactured. After forming the electron transport region ETR (see Figure 12 ) by providing composition COP including metal nanoparticles NP (see Figure 5A and Figure 5B ), the light-emitting layer EML (see Figure 5A and Figure 5B ), the hole transport region HTR (see Figure 5A and Figure 5B ) and the second electrode EL2 (see Figure 5A and Figure 5B ) can be formed in sequence. In the embodiment of performing the manufacturing steps shown in Figure 11B , the light-emitting elements ED-b or ED-c shown in Figure 5C and Figure 5D can be manufactured. After forming the electron transport region ETR (see Figure 12 ) by providing composition COP including metal nanoparticles NP (see Figure 5C and Figure 5D ), the second electrode EL2 (see Figure 5C and Figure 5D ) can be formed.

[0213] Referring to Figure 11B , a quantum dot composition including quantum dots QD-C can be provided onto the hole transport region HTR to form the light-emitting layer EML. The quantum dot composition can include quantum dots QD-C and a solvent for dispersing the quantum dots QD-C. For example, the quantum dots QD-C can be dispersed in an organic solvent and thus can be provided by an inkjet printing method or a dispensing method.

[0214] Figure 12 is Figure 11A An enlarged schematic view of region AA', and can schematically show composition COP. Hereinafter, the description of composition COP can equally apply to Figure 11A and Figure 11B . Hereinafter, reference will be made to Figures 10 to 12 for description.

[0215] In an embodiment, composition COP including metal nanoparticles NP can be provided by an inkjet printing method or a dispensing method. Figure 11A and Figure 11B show that composition COP can be provided through nozzle NZ, but the device for providing composition COP is not limited thereto.

[0216] In an embodiment, metal nanoparticles NP can include a core MC and a ligand LD bonded to the surface M_SF of the core MC. The core MC can include a metal oxide represented by formula M-1, and the ligand LD can include a bisulfite anion derived from an ionic compound represented by formula A-1. Therefore, metal nanoparticles NP can have excellent discharge stability, and composition COP including metal nanoparticles NP can be provided by an inkjet printing method or a dispensing method. The method for manufacturing a light-emitting element according to an embodiment can include the step of providing composition COP containing metal nanoparticles NP, thereby showing excellent manufacturing efficiency.

[0217] Composition COP can include a third solvent CV for dispersing metal nanoparticles NP. And any solvent can be used as the third solvent CV without limitation as long as it is a solvent that can easily disperse metal nanoparticles NP.

[0218] The method for manufacturing a light-emitting element according to an embodiment can include the step of providing a composition including metal nanoparticles to form an electron transport region and the step of providing quantum dots to form a light-emitting layer. The composition including metal nanoparticles can be provided by an inkjet printing method or a dispensing method. The light-emitting element according to an embodiment formed by the method for manufacturing a light-emitting element according to an embodiment can include an electron transport region containing metal nanoparticles and a light-emitting layer containing quantum dots. The display device according to an embodiment can include the light-emitting element according to an embodiment.

[0219] In an embodiment, the metal nanoparticles may include a core and a ligand bonded to the surface of the core. The core may include a metal oxide, and the ligand may include an ionic compound derived from bisulfite. The ligand may include a bisulfite anion. The metal nanoparticles including the bisulfite anion may maintain excellent electron injection and electron transport characteristics and may reduce or prevent charge imbalance in the light-emitting layer. Accordingly, a light-emitting element including the metal nanoparticles according to the embodiment may exhibit excellent light-emitting efficiency. A display device according to the embodiment including the light-emitting element according to the embodiment may exhibit excellent display efficiency.

[0220] A light-emitting element according to an embodiment and a display device including the light-emitting element may exhibit excellent light-emitting efficiency by including metal nanoparticles composed of a core and a ligand including bisulfite ions.

[0221] A method for manufacturing a light-emitting element according to an embodiment may exhibit excellent manufacturing efficiency by including a step of providing metal nanoparticles composed of a core and a ligand including bisulfite ions.

[0222] Embodiments have been disclosed herein, and although terms are employed, they are used and interpreted only in a general and descriptive sense and not for purposes of limitation. Unless specifically stated otherwise, in some cases, it will be apparent to those of ordinary skill in the art that 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, those of ordinary skill in the art will understand that various changes may be made in form and detail 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 includes: a first electrode; a light-emitting layer disposed on the first electrode, the light-emitting layer including quantum dots; a second electrode disposed on the light-emitting layer; a hole transport region disposed between the first electrode and the second electrode; and an electron transport region disposed between the first electrode and the second electrode, the electron transport region including metal nanoparticles, wherein the light-emitting layer is disposed between the hole transport region and the electron transport region, the metal nanoparticles include: a core including a metal oxide; and a ligand bonded to the core, the ligand including a bisulfite derived from an ionic compound represented by Formula A-1: Formula A-1 wherein, in Formula A-1, Mp is Zn, Li, Be, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Rb, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Sb, or Ba, and --- represents an ionic bond.

2. The light-emitting element according to claim 1, wherein, The ligand includes a first ligand containing a bisulfite anion in Formula A-1 and a second ligand containing Mp in Formula A-1, and wherein, each of the first ligand and the second ligand is bonded to the surface of the core.

3. The light-emitting element according to claim 1, wherein, Based on 100 mol% of the total molar amount of the metal nanoparticles, the molar amount of the bisulfite is in the range of 5 mol% to 20 mol%.

4. The light-emitting element according to claim 1, wherein: the metal oxide includes at least one of SnO, SnO2, CuGaO2, Ga2O3, Cu2O, SrCu2O2, SrTiO3, CuAlO2, Ta2O5, NiO, BaSnO3, and TiO2; or the metal oxide is represented by Formula M-1: Formula M-1 Zn (1-q) Me q O wherein, in Formula M-1, q is a real number from 0 to 0.5, and Me is Li, Be, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Rb, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Sb, or Ba.

5. The light-emitting element according to claim 1, wherein, The quantum dots do not include cadmium.

6. The light-emitting element according to claim 1, wherein, the hole transport region is disposed between the first electrode and the light-emitting layer, and the electron transport region is disposed between the light-emitting layer and the second electrode.

7. The light-emitting element according to claim 1, wherein, the hole transport region is disposed between the light-emitting layer and the second electrode, and the electron transport region is disposed between the first electrode and the light-emitting layer.

8. A method for manufacturing a light-emitting element, wherein, The method includes: forming a first electrode; forming a light-emitting layer on the first electrode; forming a second electrode on the light-emitting layer; forming a hole transport region; and forming an electron transport region by providing a composition including metal nanoparticles, wherein One of the formation of the hole transport region and the formation of the electron transport region is performed between the formation of the first electrode and the formation of the light-emitting layer, and the other of the formation of the hole transport region and the formation of the electron transport region is performed between the formation of the light-emitting layer and the formation of the second electrode, and The metal nanoparticles include: A core comprising a metal oxide; and A ligand bonded to the core, the ligand comprising a bisulfite derived from an ionic compound represented by formula A-1: Formula A-1 Wherein, in formula A-1, Mp is Zn, Li, Be, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Rb, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Sb or Ba, and Indicates an ionic bond.

9. The method according to claim 8, wherein, The method further comprises: Generating the metal nanoparticles before the formation of the electron transport region, wherein, The generation of the metal nanoparticles comprises: Generating the core; and Providing the ionic compound to the core to generate the metal nanoparticles with the ligand bonded to the surface of the core.

10. The method according to claim 9, wherein, The generation of the core comprises: Preparing a solution comprising a first metal precursor containing a first metal, a second metal precursor containing a second metal different from the first metal, and a first solvent; and Providing a second solvent different from the first solvent, and The first metal and the second metal each independently comprise Li, Be, Na, Mg, Al, K, Ca, Ta, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Rb, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Zn, Sb or Ba.

11. The method according to claim 10, wherein, The first metal precursor is a zinc precursor, The second metal precursor is a magnesium precursor, and The zinc precursor and the magnesium precursor each independently comprise an acetate ion or a halide ion.

12. The method according to claim 10, wherein, The first solvent comprises at least one of ethanol and dimethyl sulfoxide.

13. The method according to claim 10, wherein, The second solvent comprises at least one of potassium hydroxide, sodium hydroxide, trimethylammonium hydroxide and tetramethylammonium hydroxide.

14. The method according to claim 8, wherein, Based on 100 mol% of the total moles of the metal nanoparticles, the mole number of the bisulfite is in the range of 5 mol% to 20 mol%.

15. A display device, wherein, The display device comprises: A substrate layer; and A display element layer provided on the substrate layer, the display element layer comprising a light-emitting element according to any one of claims 1 to 7.

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