Light emitting element and display device including the same

Abstract

The invention relates to a light emitting element and a display device including the same. Provided is a light-emitting element including: a first electrode; a second electrode facing the first electrode; an emission structure between the first electrode and the second electrode; a first capping layer on the second electrode and including a first compound having a first refractive index of about 1.9 or greater at a wavelength of about 550 nm and a metal dopant having an absorptivity of about 40% or greater at a wavelength of about 550 nm; and a second capping layer on the first capping layer and including a second compound having a second refractive index smaller than the first refractive index, and thus reducing reflectivity to external light, thereby exhibiting excellent luminous efficiency characteristics.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority and benefit of Korean Patent Application No. 10 - 2023 - 0188527, filed on December 21, 2023, the entire disclosure of which is incorporated herein by reference. Technical field

[0003] Embodiments of the present disclosure relate to a light - emitting element and a display device including the light - emitting element, and, for example, to a light - emitting element including a plurality of capping layers stacked in sequence and a display device including the light - emitting element. Background art

[0004] Various suitable types (or kinds) of display devices for multimedia devices (such as televisions, mobile phones, tablet computers, navigation systems, and game consoles) are being developed. Among these display devices, so - called self - emissive display elements are used, which achieve display by making a light - emitting material containing an organic compound and / or quantum dots emit light.

[0005] When applying a light - emitting element to a display device, in order to improve the display quality, it is beneficial to reduce the reflectance to external light while maintaining the high luminous efficiency of the light - emitting element. Summary of the invention

[0006] Embodiments of the present disclosure provide a light - emitting element in which light reflected and emitted by an electrode is minimized or reduced.

[0007] Embodiments of the present disclosure also provide a display device having improved display quality by minimizing or reducing external reflected light.

[0008] Embodiments of the present disclosure provide a light - emitting element, including: a first electrode; a second electrode facing the first electrode; an emission structure between the first electrode and the second electrode; a first capping layer on the second electrode and including a first compound having a first refractive index of about 1.9 or more at a wavelength of about 550 nm and a metal dopant having an absorption rate of about 40% or more at a wavelength of about 550 nm; and a second capping layer on the first capping layer and including a second compound having a second refractive index less than the first refractive index.

[0009] In an embodiment, the difference between the first refractive index and the second refractive index may be about 0.2 or more.

[0010] In an embodiment, the second refractive index may be about 1.4 to about 1.7.

[0011] In an embodiment, the metal dopant may be an alkali metal, an alkaline earth metal, a lanthanide metal, and / or a transition metal.

[0012] In an embodiment, the metal dopant can be lithium (Li) and / or ytterbium (Yb).

[0013] In an embodiment, the volume ratio of the first compound to the metal dopant in the first capping layer can be from about 99:1 to about 95:5.

[0014] In an embodiment, the thickness of the first capping layer and the thickness of the second capping layer can each independently be about to about

[0015] In an embodiment, the emission structure can include: an emission layer on the first electrode; a hole transport region between the first electrode and the emission layer; and an electron transport region between the emission layer and the second electrode.

[0016] In an embodiment, the emission structure can include: a plurality of emission units stacked in sequence and each including a hole transport region, an emission layer, and an electron transport region; and a charge generation layer between each pair of adjacent emission units among the plurality of emission units between the first electrode and the second electrode.

[0017] In an embodiment, the emission structure can emit blue light.

[0018] In an embodiment, the first compound can be an organic material, and the second compound can be an organic material or an inorganic material.

[0019] In an embodiment of the present disclosure, a display device includes: a light-emitting element that emits source light; and an optical control layer on the light-emitting element and that transmits the source light or converts the wavelength of the source light, wherein the light-emitting element includes: a first electrode; a second electrode facing the first electrode; an emission structure between the first electrode and the second electrode; a first capping layer on the second electrode and including a first compound having a first refractive index of about 1.9 or greater at a wavelength of 550 nm and a metal dopant having an absorption rate of about 40% or greater at a wavelength of 550 nm; and a second capping layer on the first capping layer and including a second compound having a second refractive index less than the first refractive index.

[0020] In an embodiment, the difference between the first refractive index and the second refractive index can be about 0.2 or greater, and the second refractive index can be from about 1.4 to about 1.7.

[0021] In an embodiment, the metal dopant can be an alkali metal, an alkaline earth metal, a lanthanide metal, and / or a transition metal.

[0022] In an embodiment, the volume ratio of the first compound to the metal dopant in the first capping layer can be from about 99:1 to about 95:5.

[0023] In an embodiment, the thickness of the first capping layer and the thickness of the second capping layer may each independently be about to about

[0024] In an embodiment, a display device may include: a first pixel region that emits red light; a second pixel region that emits green light; and a third pixel region that emits blue light, wherein the first pixel region, the second pixel region, and the third pixel region do not overlap with each other in a plane, and wherein the optical control layer includes: a first optical control member provided corresponding to the first pixel region and including first quantum dots that convert the wavelength of source light; a second optical control member provided corresponding to the second pixel region and including second quantum dots that convert the wavelength of source light; and a third optical control member provided corresponding to the third pixel region.

[0025] In an embodiment of the present disclosure, a display device includes: a circuit layer; a light-emitting element on the circuit layer; and a packaging layer on the light-emitting element, wherein the light-emitting element includes: a first electrode; a second electrode facing the first electrode; an emission structure between the first electrode and the second electrode; a first capping layer on the second electrode and including a first compound having a first refractive index of about 1.9 or greater at a wavelength of 550 nm and a metal dopant having an absorption rate of about 40% or greater at a wavelength of 550 nm; and a second capping layer on the first capping layer and including a second compound having a second refractive index less than the first refractive index.

[0026] In an embodiment, the packaging layer may be directly on the second capping layer.

[0027] In an embodiment, the volume ratio of the first compound to the metal dopant in the first capping layer may be about 99:1 to about 95:5. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are included to provide a further understanding of the subject matter of the present disclosure and are incorporated into and constitute a part of this specification. The drawings illustrate embodiments of the present disclosure and, together with the description, are used to explain the principles of the present disclosure. In the drawings:

[0029] Figure 1A is a perspective view of a display device according to an embodiment;

[0030] Figure 1B is a cross-sectional view of a display device according to an embodiment;

[0031] Figure 1C is a plan view of a display device according to an embodiment;

[0032] Figure 2 is an enlarged plan view of a part of a display device according to an embodiment;

[0033] Figure 3 A cross-sectional view of a part of a display device according to an embodiment;

[0034] Figure 4 A cross-sectional view of a part of a display device according to an embodiment;

[0035] Figure 5 A cross-sectional view of a light-emitting element according to an embodiment;

[0036] Figure 6A A cross-sectional view of a light-emitting element according to an embodiment;

[0037] Figure 6B A cross-sectional view for explaining an emission unit included in a light-emitting element according to an embodiment; and

[0038] Figure 7 A graph comparing the absorption rates of metal dopants according to wavelength. Detailed Description

[0039] In the present disclosure, various suitable modifications can be made, various suitable forms can be applied, and exemplary embodiments will be illustrated in the drawings and described in more detail in the detailed description. However, this is not intended to limit the present disclosure to the specific disclosed forms, and the present disclosure should be understood to include all changes, equivalents, and substitutions included within the spirit and scope of the present disclosure.

[0040] As used herein, when a component (or region, layer, part, etc.) is referred to as being "on" another component (or region, layer, part, etc.), "connected to" another component (or region, layer, part, etc.), or "adhered to" another component (or region, layer, part, etc.), it can be directly "disposed on" another component (or region, layer, part, etc.) / "connected to" another component (or region, layer, part, etc.) / "adhered to" another component (or region, layer, part, etc.), or there may also be a third intervening component (or region, layer, part, etc.) therebetween.

[0041] The same reference numerals and symbols refer to the same elements. In the embodiments, in the drawings, for the effective description of the technical content, the thickness, ratio, and dimensions of the elements may be enlarged. The term "and / or" includes all combinations of one or more related configurations that can be defined.

[0042] 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. For example, without departing from the teachings of the present disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. The singular form is intended to also include the plural form unless the context clearly indicates otherwise.

[0043] Also, terms such as "below", "lower side", "above", and "upper side" may be used to describe the relationship of components shown in the drawings. The terms are used as relative concepts and are described with reference to the directions indicated in the drawings.

[0044] It should be understood that terms such as "include" and "have" are intended to indicate the presence of the recited features, integers, actions, tasks, operations, elements, components, or any combination thereof in the present disclosure, but do not preclude the presence or addition of one or more other features, integers, actions, tasks, operations, elements, components, or any combination thereof.

[0045] As used herein, when an element is referred to as being "directly on" another element or layer, there is no intervening layer, film, region, plate, etc. between them. For example, the expression that a layer or member is "directly on" another layer or member may mean that two layers or two members are provided without using another member therebetween.

[0046] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Also, terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0047] Hereinafter, quantum dots, light-emitting elements, and display devices including the light-emitting elements according to embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0048] Figure 1A is a perspective view of a display device according to an embodiment. Figure 1B is a cross-sectional view of a display device according to an embodiment. Figure 1C is a plan view of a display device according to an embodiment. Figure 1B is along Figure 1A a cross-sectional view of a cross-section taken along line I-I' in

[0049] The display device DD according to an embodiment can be activated in response to an electrical signal and can display an image. For example, the display device DD can be a medium or small device (such as a monitor, a mobile phone, a tablet computer, a navigation unit, and / or a game console), as well as a large device (such as a television and / or an outdoor billboard). However, these devices are shown as examples, and the display device DD according to an embodiment is not limited thereto without departing from the concept of the present disclosure.

[0050] The display device DD may be rigid or flexible. The term "flexible" may refer to the property of being able to bend. For example, a flexible display device DD may include a curved surface device, a rollable device, and / or a foldable device.

[0051] In Figure 1A and the subsequent drawings, first to third direction axes DR1, DR2, and DR3 are illustrated. The directions indicated by the first to third direction axes DR1, DR2, and DR3 as described herein are relative concepts and may be converted to other directions. In an embodiment, the directions indicated by the first to third direction axes DR1, DR2, and DR3 may be described as first to third directions DR1, DR2, and DR3 and the same reference numerals and numbers may be used. As used herein, the first direction axis DR1 and the second direction axis DR2 may be perpendicular to each other, and the third direction axis DR3 may be the normal direction of the plane defined by the first direction axis DR1 and the second direction axis DR2.

[0052] The thickness direction of the display device DD may be parallel to the third direction axis DR3, which is the normal direction of the plane defined by the first direction axis DR1 and the second direction axis DR2. As used herein, the front surface (or top surface) and the rear surface (or bottom surface) of the components constituting the display device DD may be defined on the third direction axis DR3. The front surface (or top surface) and the rear surface (or bottom surface) of the components constituting the display device DD may be opposite to each other in the third direction DR3, and the respective normal directions of the front surface and the rear surface may be substantially parallel to the third direction DR3. The spaced distance between the front surface and the rear surface defined along the third direction DR3 may correspond to the thickness of the component.

[0053] As used herein, the term "in a plane" may be defined as a state observed in the third direction DR3. As used herein, the term "in a cross-section" may be defined as a state observed in the first direction DR1 or the second direction DR2. In an embodiment, the directions indicated by the first to third directions DR1, DR2, and DR3 are relative concepts and may be changed to another direction.

[0054] The display device DD according to an embodiment may display an image through a display surface IS. The display surface IS may be the plane defined by the first direction DR1 and the second direction DR2. The display surface IS may include a display area DA and a non-display area NDA. A plurality of pixel units PXU may be in the display area DA and may not be in the non-display area NDA. The non-display area NDA may be defined along the edge of the display surface IS. The non-display area NDA may surround the display area DA. However, the embodiments of the present disclosure are not limited thereto, and in the embodiments of the present disclosure, the non-display area NDA may be omitted, or the non-display area NDA may be provided only on one side of the display area DA.

[0055] The pixel unit PXU may define a scan line and a pixel column. The pixel unit PXU is the smallest repeating unit and may include at least one pixel. The pixel unit PXU may include a plurality of pixels that provide light of different colors.

[0056] In an embodiment of the present disclosure, a display device DD provided with a flat display surface IS is illustrated, but is not limited thereto. The display device DD may include a curved display surface or a three-dimensional display surface. The three-dimensional display surface may include a plurality of display areas indicating different directions from each other.

[0057] Reference Figure 1B , the display device DD may include a base layer BS, a circuit layer DP-CL, and a display layer DP-ED that are sequentially stacked in the direction of the third direction axis DR3. In an embodiment, the display device DD according to the embodiment may further include an optical control member OSL on the display layer DP-ED.

[0058] The base layer BS may be a support substrate provided with the circuit layer DP-CL and the display layer DP-ED. The circuit layer DP-CL includes at least one insulating layer (e.g., an electrical insulating layer) and circuit elements. The circuit elements include signal lines and / or drive circuits of pixels, etc. The circuit layer DP-CL may be formed by a forming process of coating and / or depositing an insulating layer (e.g., an electrical insulating layer), a semiconductor layer, and a conductive layer (e.g., a conductive layer), and a patterning process of using photolithography for the insulating layer, the semiconductor layer, and the conductive layer. The display layer DP-ED includes display elements. The optical control member OSL may convert the wavelength of the light provided by the display elements, or may transmit the light provided by the display elements. The optical control member OSL may include a light control pattern and structure for increasing the conversion efficiency of light.

[0059] In Figure 1C , the placement relationship of the signal lines GL1 to GLn, DL1 to DLm, and the pixels PX11 to PXnm on a plane is illustrated. The signal lines GL1 to GLn and DL1 to DLm may include a plurality of gate lines GL1 to GLn and a plurality of data lines DL1 to DLm.

[0060] Each of the pixels PX11 to PXnm is connected to a corresponding one of the plurality of gate lines GL1 to GLn and a corresponding one of the plurality of data lines DL1 to DLm. Each of the pixels PX11 to PXnm may include a pixel drive circuit and a display element. Depending on the configuration of the pixel drive circuits of the pixels PX11 to PXnm, more types (or kinds) of signal lines may be provided in the display device DD.

[0061] Although the matrix-type pixels PX11 to PXnm are illustrated as an example, the arrangement form of the pixels PX11 to PXnm is not limited thereto.

[0062] In an embodiment, the gate driving circuit GDC may be integrated into the display device DD through an oxide silicon gate driving circuit (OSG) process or an amorphous silicon gate driving circuit (ASG) process.

[0063] Figure 2 An enlarged plan view of a part of a display device according to an embodiment. Refer to Figure 2 , in an embodiment, a plurality of pixel units PXU may be in the display area DA. The plurality of pixel units PXU may each be arranged in a first direction DR1 and a second direction DR2. In an embodiment, the pixel unit PXU may include a first pixel, a second pixel, and a third pixel that emit light in different wavelength regions. Red light, green light, and blue light may be output from the first pixel, the second pixel, and the third pixel, respectively. In Figure 2 , a first pixel region PXA-R, a second pixel region PXA-G, and a third pixel region PXA-B that respectively represent the first pixel, the second pixel, and the third pixel are illustrated. The first pixel region PXA-R is a region where light generated from the first pixel is provided to the outside, the second pixel region PXA-G is a region where light generated from the second pixel is provided to the outside, and the third pixel region PXA-B may be a region where light generated from the third pixel is provided to the outside. When viewed on a plane, the first to third pixel regions PXA-R, PXA-G, and PXA-B may be separated from each other without overlapping.

[0064] Refer to Figure 2 , in an embodiment, three types (or kinds) of pixel regions PXA-R, PXA-G, and PXA-B may be repeatedly arranged throughout the display area DA. The pixel regions PXA-R, PXA-G, and PXA-B may also be referred to as emission regions.

[0065] In an embodiment, the first pixel region PXA-R is a red emission region that emits red light, the second pixel region PXA-G is a green emission region that emits green light, and the third pixel region PXA-B may be a blue emission region that emits blue light. However, embodiments of the present disclosure are not limited thereto, and in an embodiment, in addition to the first to third pixel regions PXA-R, PXA-G, and PXA-B, a pixel region that emits white light may be further included in the display area DA.

[0066] A peripheral region NPXA is provided around the first to third pixel regions PXA-R, PXA-G, and PXA-B. The peripheral region NPXA may be referred to as a non-emission region. The peripheral region NPXA sets the boundaries of the first to third pixel regions PXA-R, PXA-G, and PXA-B.

[0067] The outer peripheral region NPXA may be arranged to surround each of the first pixel region PXA-R, the second pixel region PXA-G, and the third pixel region PXA-B. In an embodiment, the outer peripheral region NPXA may be between the first pixel region PXA-R, the second pixel region PXA-G, and the third pixel region PXA-B. The outer peripheral region NPXA may define the boundaries of the first to third pixel regions PXA-R, PXA-G, and PXA-B, and may prevent or reduce color mixing between the first to third pixel regions PXA-R, PXA-G, and PXA-B. In the outer peripheral region NPXA, a structure for preventing or reducing color mixing between the first to third pixel regions PXA-R, PXA-G, and PXA-B may be provided, such as a pixel defining layer PDL( Figure 3 ) and a partition pattern BMP( Figure 3 ).

[0068] In Figure 2 , a display device DD (FIG. 1) including first to third pixel regions PXA-R, PXA-G, and PXA-B having the same planar shape as each other and different areas from each other is illustrated as an example, but embodiments of the present disclosure are not limited thereto. The areas of the first to third pixel regions PXA-R, PXA-G, and PXA-B may all be the same, or the area of at least one type (or kind) of pixel region may be different from the areas of the remaining type (or kind) of pixel regions. The areas of the first to third pixel regions PXA-R, PXA-G, and PXA-B may be set according to the color of the emitted light.

[0069] Referring to Figure 2 , in a plane, the first to third pixel regions PXA-R, PXA-G, and PXA-B may have a rectangular shape. However, embodiments of the present disclosure are not limited thereto, and in a plane, the first to third pixel regions PXA-R, PXA-G, and PXA-B may have different polygonal shapes (including substantially polygonal shapes), such as a rhombus and a pentagon. The first to third pixel regions PXA-R, PXA-G, and PXA-B may have a rectangular shape with rounded corners in a plane (e.g., a substantially rectangular shape).

[0070] In Figure 2 , as an example, it is illustrated that the second pixel region PXA-G is provided in the first row, and the first pixel region PXA-R and the third pixel region PXA-B are provided in a second row different from the first row, but embodiments of the present disclosure are not limited thereto, and the placement of the first to third pixel regions PXA-R, PXA-G, and PXA-B may be changed in various suitable ways. For example, the first to third pixel regions PXA-R, PXA-G, and PXA-B may be provided in the same row.

[0071] Multiple pixel regions PXA-R, PXA-G, and PXA-B may be arranged in a stripe shape and may have an arrangement structure (e.g., an RGBG matrix, an RGBG structure, or an RGBG matrix structure), or may have a DIAMOND arrangement structure. is a trademark officially registered by Samsung Display Co., Ltd., and DIAMOND is a trademark officially registered by Samsung Display Co., Ltd. However, embodiments of the present disclosure are not limited thereto, and the arrangement order and arrangement form of the multiple pixel regions PXA-R, PXA-G, and PXA-B may be provided in various appropriate combinations depending on the characteristics of the display quality required or desired by the display device DD (FIG. 1).

[0072] Figure 3 and Figure 4 are cross-sectional views of respective parts of a display device according to an embodiment. Figure 3 may be a cross-sectional view of a cross-section taken along line II-II' in Figure 2 , and Figure 4 may be a cross-sectional view of a cross-section taken along line III-III' in Figure 2 .

[0073] Referring to Figure 3 and Figure 4 , a display device DD according to an embodiment may include a base layer BS, a circuit layer DP-CL on the base layer BS, and a display layer DP-ED on the circuit layer DP-CL. As used herein, the stacked structure including the base layer BS, the circuit layer DP-CL, and the display layer DP-ED may be referred to as a bottom panel or a display panel. Different from Figure 3 , the configuration of the circuit layer DP-CL and the encapsulation layer TFE is simply illustrated in Figure 4 , and a part of the multiple pixel regions PXA-R, PXA-G, and PXA-B of the display device DD is illustrated.

[0074] The base layer BS may be a member providing a base surface, and the configurations included in the circuit layer DP-CL are provided on the base surface. In an embodiment, the base layer BS may be a glass substrate, a metal substrate, and / or a polymer substrate, etc. However, embodiments of the present disclosure are not limited thereto, and the base layer BS may be an inorganic functional layer or a composite material layer.

[0075] The base layer BS may have a multi-layer structure. For example, the base layer BS may have a three-layer structure of a polymer resin layer, an adhesive layer, and a polymer resin layer. In an embodiment, the polymer resin layer may include a polyimide resin. In an embodiment, the polymer resin layer may include an acrylic resin (e.g., a methacrylic resin), a polyisoprene resin, a vinyl resin, an epoxy resin, a urethane resin, a cellulose resin, a silicone resin, a polyamide resin, and / or a perylene resin. In an embodiment, as used herein, the term "α-type" resin refers to a resin including an "α-type" functional group.

[0076] The circuit layer DP-CL may be on the base layer BS. The circuit layer DP-CL may include a plurality of transistors. Each of the plurality of transistors may include a control electrode, an input electrode, and an output electrode. For example, the circuit layer DP-CL may include a switching transistor and a driving transistor that drives the light-emitting element OEL of the display layer DP-ED.

[0077] In an embodiment, the circuit layer DP-CL may include a transistor T-D as a circuit element. The configuration of the circuit layer DP-CL may be appropriately changed depending on the design of the driving circuit of the pixels PX11 to PXnm ( Figure 1C ). Figure 3 One transistor T-D is illustrated as an example, and the placement relationship between the active portion A-D, the source S-D, the drain D-D, and the gate G-D that constitute the transistor T-D is provided as an example. The active portion A-D, the source S-D, and the drain D-D may be regions distinguished by the doping concentration and / or conductivity (e.g., conductance) in the semiconductor pattern.

[0078] The circuit layer DP-CL may include a buffer layer BFL, a first insulating layer 10, a second insulating layer 20, a third insulating layer 30, etc. For example, the buffer layer BFL, the first insulating layer 10, and the second insulating layer 20 may be inorganic layers, and the third insulating layer 30 may be an organic layer.

[0079] The display layer DP-ED may be on the circuit layer DP-CL. The display layer DP-ED may include a pixel defining layer PDL, a light-emitting element OEL, and a packaging layer TFE. The light-emitting element OEL may be electrically connected to the driving element of the circuit layer DP-CL, and may display an image by generating light in response to a signal provided by the driving element. The display layer DP-ED may include the light-emitting element OEL as a display element. The light-emitting element OEL may generate source light.

[0080] As Figure 3 and Figure 4As described, the display device DD according to an embodiment may include an optical control member OSL on the display layer DP-ED. The optical control member OSL may include an optical control layer CCL. In an embodiment, the optical control layer CCL may include quantum dots. In addition to the optical control layer CCL, the optical control member OSL may further include a low refractive index layer LR, a color filter layer CFL, and a base substrate BL. As used herein, the optical control member OSL may be referred to as a top panel.

[0081] The optical control layer CCL may be on the display layer DP-ED including the light-emitting element OEL. The optical control layer CCL may include a partition pattern BMP and optical control elements CCP-R, CCP-G, and CCP-B. The partition pattern BMP may be a component that separates the plurality of optical control elements CCP-R, CCP-G, and CCP-B from each other.

[0082] The partition pattern BMP may include a base resin and additives. The base resin may be formed of various suitable resin compositions commonly referred to as binders. The additives may include a coupling agent and / or a photoinitiator. The additives may further include a dispersant.

[0083] The partition pattern BMP may include a black colorant for blocking light. The partition pattern BMP may include a black dye and / or a black pigment mixed into the base resin. In an embodiment, the black dye and / or the black pigment may include carbon black and / or may include a metal such as chromium and / or a metal oxide.

[0084] An opening BW-OH corresponding to the light-emitting opening OH may be defined in the partition pattern BMP. In a plane, the opening BW-OH overlaps with the light-emitting opening OH and has an area larger than the area of the light-emitting opening OH. In an embodiment, the opening BW-OH may have an area larger than the areas of the emission regions EA1, EA2, and EA3 defined by the light-emitting opening OH. The optical control elements CCP-R, CCP-G, and CCP-B may be inside the opening BW-OH.

[0085] In an embodiment, the optical control layer CCL may include a first optical control element CCP-R corresponding to the first pixel region PXA-R, a second optical control element CCP-G corresponding to the second pixel region PXA-G, and a third optical control element CCP-B corresponding to the third pixel region PXA-B. The first optical control element CCP-R may be a red optical control element that emits red light, and the second optical control element CCP-G may be a green optical control element that emits green light. The third optical control element CCP-B may be a blue optical control element that emits blue light. In an embodiment, the third optical control element CCP-B may be a transmissive optical control element that emits the source light provided from the display layer DP-ED by transmitting the source light.

[0086] At least some of the plurality of optical control elements CCP-R, CCP-G, and CCP-B can change the optical characteristics of the source light. In an embodiment, at least some of the optical control elements CCP-R, CCP-G, and CCP-B can include quantum dots that change the optical characteristics of the source light.

[0087] In an embodiment, the first optical control element CCP-R can include quantum dots that change the optical characteristics of the source light. The quantum dots included in the first optical control element CCP-R can convert the source light into light having a different wavelength. For example, in the first optical control element CCP-R overlapping with the first pixel region PXA-R, the quantum dots can convert the source light into red light.

[0088] In this specification, the term quantum dot refers to a crystal of a semiconductor compound. Depending on the particle size of the crystal, the quantum dot can emit light having various appropriate emission wavelengths. By adjusting the element ratio in the quantum dot compound, the quantum dot can emit light having various appropriate emission wavelengths.

[0089] The quantum dot can have, for example, a diameter of about 1 nm to about 10 nm. The quantum dot can be synthesized by a wet chemical process, a metalorganic chemical vapor deposition (MOCVD) process, a molecular beam epitaxy (MBE) process, and / or a similar process.

[0090] Among the quantum dot manufacturing processes, the wet chemical process is a method of growing quantum dot particle crystals after mixing an organic solvent and a precursor material. When the quantum dot particle crystals grow, the organic solvent can naturally act as a dispersant coordinated to the surface of the quantum dot particle crystals and can control the growth of the quantum dot particle crystals. Therefore, the wet chemical process is easier than vapor deposition methods (such as the metalorganic chemical vapor deposition (MOCVD) process or the molecular beam epitaxy (MBE) process), and the growth of the quantum dot particle crystals can be controlled by a low-cost process.

[0091] The core of the quantum dot can be selected from group II-VI compounds, group III-V compounds, group III-VI compounds, group I-III-VI compounds, group IV-VI compounds, group II-IV-V compounds, group IV elements, group IV compounds, and any combination thereof.

[0092] The Group II-VI compounds can be selected from the group consisting of: binary compounds selected from the group consisting of CdSe, CdTe, CdS, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, and mixtures thereof; ternary compounds selected from the group consisting of CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, and mixtures thereof; and quaternary compounds selected from the group consisting of HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and mixtures thereof. In an embodiment, the Group II-VI compounds may further include Group I metals and / or Group IV elements. CuZnS etc. can be selected as the Group I-II-VI compounds, CuSnS etc. can be selected as the Group I-IV-VI compounds, and ZnSnS etc. can be selected as the Group II-IV-VI compounds. The Group I-II-IV-VI compounds can be selected from quaternary compounds selected from the group consisting of Cu2ZnSnS2, Cu2ZnSnS4, Cu2ZnSnSe4, Ag2ZnSnS2, and mixtures thereof.

[0093] The Group III-VI compounds can include binary compounds (such as, In2S3, In2Se3), ternary compounds (such as, InGaS3, InGaSe3), or any combination thereof.

[0094] The Group I-III-VI compounds can be selected from the group consisting of: ternary compounds selected from the group consisting of AgInS, AgInS2, CuInS, CuInS2, AgGaS2, CuGaS2, CuGaO2, AgGaO2, AgAlO2, and mixtures thereof; and / or quaternary compounds (such as, AgInGaS2 and / or CuInGaS2).

[0095] The Group III-V compound may be selected from the group consisting of: binary compounds selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and mixtures thereof; ternary compounds selected from the group consisting of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InAlP, InNP, InNAs, InNSb, InPAs, InPSb, and mixtures thereof; and quaternary compounds selected from the group consisting of GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and mixtures thereof. In an embodiment, the Group III-V compound may further include a Group II metal. For example, InZnP or the like may be selected as the Group III-II-V compound.

[0096] The Group IV-VI compound may be selected from the group consisting of: binary compounds selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe, and mixtures thereof; ternary compounds selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and mixtures thereof; and quaternary compounds selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe, and mixtures thereof.

[0097] Examples of the Group II-IV-V compound may be ternary compounds selected from the group consisting of ZnSnP, ZnSnP2, ZnSnAs2, ZnGeP2, ZnGeAs2, CdSnP2, CdGeP2, and mixtures thereof.

[0098] The Group IV element may be selected from the group consisting of Si, Ge, and mixtures thereof. The Group IV compound may be a binary compound selected from the group consisting of SiC, SiGe, and mixtures thereof.

[0099] Each element contained in a multi-component compound (such as a binary compound, a ternary compound, and a quaternary compound) may be present in the particles at a uniform concentration or a non-uniform concentration. In an embodiment, the formula representing the quantum dots may mean the type (or species) of elements included in the compound, and the element ratios in the compound may be different. For example, AgInGaS2 may mean AgIn x Ga1-x S2 (where 0 < x < 1).

[0100] In this case, the binary compound, ternary compound, and / or quaternary compound may be present in the particles at a uniform concentration, or may be present in the same particle and simultaneously divided into states with different concentration distribution portions. In an embodiment, the binary compound, ternary compound, and / or quaternary compound may also have a core-shell structure in which one quantum dot surrounds another quantum dot. The core-shell structure may have a concentration gradient in which the concentration of the elements present in the shell gradually decreases along the direction toward the center of the core.

[0101] In some embodiments, the quantum dot may have a core-shell structure including a core containing the above-described nanoparticles and a shell surrounding the core. The shell of the quantum dot can be used as a protective layer for preventing or reducing chemical denaturation of the core to maintain semiconductor characteristics and / or a charging layer for imparting electrophoretic characteristics to the quantum dot. The shell can be a single layer or multiple layers. Examples of the shell of the quantum dot may include oxides of metals, oxides of non-metals, semiconductor compounds, or any combination thereof.

[0102] For example, examples of oxides of metals or oxides of non-metals may include: binary compounds (such as, SiO2, Al2O3, TiO2, ZnO, MnO, Mn2O3, Mn3O4, CuO, FeO, Fe2O3, Fe3O4, CoO, Co3O4, and / or NiO); and / or ternary compounds (such as, MgAl2O4, CoFe2O4, NiFe2O4, and / or CoMn2O4), but the embodiments of the present disclosure are not limited thereto.

[0103] In addition, examples of semiconductor compounds may include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, and / or AlSb, etc. However, the embodiments of the present disclosure are not limited thereto.

[0104] The quantum dot may have a full width at half maximum (FWHM) of an emission wavelength spectrum of about 45 nm or less, for example, about 40 nm or less, or about 30 nm or less. When the FWHM falls within these ranges, color purity and / or color reproducibility can be improved. In an embodiment, the light emitted by the quantum dot can be emitted in all directions (e.g., substantially all directions), and thus the optical viewing angle can be improved.

[0105] In an embodiment, the form of the quantum dots is not particularly limited as long as it is a form commonly used in the art. However, for example, quantum dots in the form of spherical nanoparticles, cone nanoparticles, multi-arm nanoparticles, and / or cube nanoparticles, nanotubes, nanowires, nanofibers, and / or nanosheets can be used.

[0106] The band gap of the quantum dots can be adjusted by adjusting the particle size of the quantum dots and / or adjusting the element ratio in the quantum dot compound, and thus light with various appropriate wavelengths can be emitted in the quantum dot emission layer. Therefore, when using quantum dots as previously described (for example, quantum dots with different particle sizes and / or different element ratios in the quantum dot compound), a light-emitting element that emits light with various appropriate wavelengths can be achieved. In an embodiment, the particle size of the quantum dots and / or the element ratio in the quantum dot compound can be selected for the red light, green light, and / or blue light to be emitted. In an embodiment, the quantum dots can be configured to emit white light by combining light with various colors.

[0107] In an embodiment, the quantum dots included in the first optical control element CCP-R overlapping the first pixel region PXA-R can emit red light. As the particle size of the quantum dots becomes smaller, the quantum dots can emit light with a shorter wavelength. For example, among quantum dots with the same core, the particle size of the quantum dots that emit green light can be smaller than the particle size of the quantum dots that emit red light. In an embodiment, among quantum dots with the same core, the particle size of the quantum dots that emit blue light can be smaller than the particle size of the quantum dots that emit green light. However, the embodiments of the present disclosure are not limited thereto, and even when the quantum dots have the same core, the particle size of the quantum dots can be adjusted according to the material used to form the shell and / or the thickness of the shell, etc.

[0108] In an embodiment, when the quantum dots emit light of various appropriate colors (such as blue, red, and green), the quantum dots that emit light of different colors can have different core materials.

[0109] The optical control elements CCP-R, CCP-G, and CCP-B of the optical control layer CCL can include a scatterer (for example, a light scatterer). The first optical control element CCP-R can include quantum dots that convert the source light into red light and a scatterer that scatters light.

[0110] The scatterer can be inorganic particles. For example, the scatterer can include at least one of TiO2, ZnO, Al2O3, SiO2, and hollow silica. The scatterer can contain any one of TiO2, ZnO, Al2O3, SiO2, and hollow silica, or can be a mixture of two or more materials selected from TiO2, ZnO, Al2O3, SiO2, and hollow silica.

[0111] In an embodiment, some descriptions of the first optical control element CCP-R above can be similarly applied to the second optical control element CCP-G and the third optical control element CCP-B.

[0112] In an embodiment, the second optical control element CCP-G may include quantum dots that change the optical characteristics of the source light. The quantum dots included in the second optical control element CCP-G may convert the source light into light having a different wavelength. For example, in the second optical control element CCP-G overlapping with the second pixel region PXA-G, the quantum dots may convert the source light into green light.

[0113] In an embodiment, the third optical control element CCP-B overlapping with the third pixel region PXA-B may not include quantum dots. However, embodiments of the present disclosure are not limited thereto, and the third optical control element CCP-B may include quantum dots that convert the wavelength of some of the source light provided by the light-emitting element OEL.

[0114] The second optical control element CCP-G and the third optical control element CCP-B may also further include a scatterer (e.g., a light scatterer). For example, in an embodiment, the first optical control element CCP-R may include a first quantum dot and a scatterer (e.g., a light scatterer), the second optical control element CCP-G may include a second quantum dot and a scatterer (e.g., a light scatterer), and the third optical control element CCP-B may not include a quantum dot but may include a scatterer (e.g., a light scatterer).

[0115] The second optical control element CCP-G and the third optical control element CCP-B may each also include a base resin that disperses the quantum dots and the scatterer.

[0116] In the optical control member OSL according to the embodiment Figure 3 and Figure 4 illustrated in, the base substrate BL may be a member that provides a base surface, and a color filter layer CFL, a low refractive index layer LR, an optical control layer CCL, etc. are provided on the base surface. However, embodiments of the present disclosure are not limited thereto, and the base substrate BL may be an inorganic layer, an organic layer, or a composite material layer. In an embodiment, the base substrate BL may be omitted.

[0117] In an embodiment, an antireflection layer (not shown) may be on the base substrate BL. The antireflection layer may be an optical functional layer that reduces the reflectance of external light incident from the outside. The antireflection layer may selectively transmit light emitted from the display device DD. In an embodiment, the antireflection layer may be a single layer containing a dye and / or a pigment dispersed in a base resin. The antireflection layer may be provided as a single continuous layer that completely overlaps all of the first to third pixel regions PXA-R, PXA-G, and PXA-B.

[0118] The antireflection layer may not include a polarizer. Thus, the light passing through the antireflection layer and incident on the display layer DP-ED may be unpolarized light. The display layer DP-ED may receive the unpolarized light from the top of the antireflection layer.

[0119] In an embodiment, the optical control member OSL may include the isolation layers CAP1 and CAP2. The isolation layers CAP1 and CAP2 may be used to prevent or reduce the penetration of moisture and / or oxygen (hereinafter referred to as "moisture / oxygen"), and improve the optical characteristics of the optical control member OSL by controlling the refractive index. The isolation layers CAP1 and CAP2 may be above and / or below the optical control elements CCP-R, CCP-G, and CCP-B. The isolation layers CAP1 and CAP2 may be only on the top surface or the bottom surface of the optical control elements CCP-R, CCP-G, and CCP-B, and may block or reduce the exposure of the optical control elements CCP-R, CCP-G, and CCP-B to moisture / oxygen, and for example, may block or reduce the exposure of the quantum dots included in the optical control elements CCP-R, CCP-G, and CCP-B to moisture / oxygen. The isolation layers CAP1 and CAP2 may also protect the optical control elements CCP-R, CCP-G, and CCP-B from external impacts.

[0120] In an embodiment, the first isolation layer CAP1 may be spaced apart from the display layer DP-ED, and the optical control elements CCP-R, CCP-G, and CCP-B may be between the first isolation layer CAP1 and the display layer DP-ED. In an embodiment, the first isolation layer CAP1 may be on the top surface of the optical control elements CCP-R, CCP-G, and CCP-B. In an embodiment, the optical control member OSL may further include a second isolation layer CAP2 between the optical control elements CCP-R, CCP-G, and CCP-B and the display layer DP-ED. In an embodiment, the first isolation layer CAP1 may cover the top surface of the optical control elements CCP-R, CCP-G, and CCP-B adjacent to the low refractive index layer LR, and the second isolation layer CAP2 may cover the bottom surface of the optical control elements CCP-R, CCP-G, and CCP-B adjacent to the display layer DP-ED. In an embodiment, as used herein, the term "top surface" may be the surface on the upper side with respect to the third direction DR3, and the term "bottom surface" may be the surface on the lower side with respect to the third direction DR3.

[0121] In an embodiment, the first isolation layer CAP1 and the second isolation layer CAP2 may cover the segmentation pattern BMP and one surface of the optical control elements CCP-R, CCP-G, and CCP-B.

[0122] The first isolation layer CAP1 may cover one surface of the segmentation pattern BMP and the adjacent low refractive index layer LR of the optical control elements CCP-R, CCP-G, and CCP-B. The second isolation layer CAP2 may be provided along the steps of the segmentation pattern BMP and the optical control elements CCP-R, CCP-G, and CCP-B.

[0123] The first isolation layer CAP1 and the second isolation layer CAP2 may be formed by including an inorganic material. In an embodiment, the first isolation layer CAP1 may include silicon oxynitride (SiO x N y ). All of the first isolation layer CAP1 and the second isolation layer CAP2 may include silicon oxynitride. However, embodiments of the present disclosure are not limited thereto, and the first isolation layer CAP1 may include silicon oxynitride, and the second isolation layer CAP2 may include silicon oxide (SiO x ).

[0124] The optical control member OSL may further include a color filter layer CFL on the optical control layer CCL. The color filter layer CFL includes at least one selected from color filters CF1, CF2, and CF3. The color filters CF1, CF2, and CF3 allow light within a set or specific wavelength range to pass through and block or reduce the transmission of light outside of that wavelength range. In an embodiment, the first color filter CF1 may be a red filter that transmits red light, the second color filter CF2 may be a green filter that transmits green light, and the third color filter CF3 may be a blue filter that transmits blue light.

[0125] Each of the color filters CF1, CF2, and CF3 includes a polymer photoresist and a colorant. The colorant may include a pigment and / or a dye. The first color filter CF1 may include a red pigment and / or a red dye, the second color filter CF2 may include a green pigment and / or a green dye, and the third color filter CF3 may include a blue pigment and / or a blue dye. In an embodiment, the third color filter CF3 may not include a pigment or a dye.

[0126] The first to third color filters CF1, CF2, and CF3 may be provided corresponding to the first pixel region PXA-R, the second pixel region PXA-G, and the third pixel region PXA-B, respectively. In an embodiment, the first to third color filters CF1, CF2, and CF3 may be provided to overlap with the first to third optical control elements CCP-R, CCP-G, and CCP-B, respectively.

[0127] In an embodiment, reference Figure 4, a plurality of color filters CF1, CF2, and CF3 that transmit different lights can be provided in a manner that overlaps with the corresponding outer peripheral region NPXA. Corresponding to the outer peripheral region NPXA, a plurality of color filters CF1, CF2, and CF3 can be provided by overlapping in the third direction DR3, which is the thickness direction, to separate the boundaries between adjacent pixel regions PXA-R, PXA-G, and PXA-B. In an embodiment, the color filter layer CFL may include a light-blocking portion (not shown) that separates the boundaries between the color filters CF1, CF2, and CF3. The light-blocking portion may be formed of a blue filter or may be formed by including an organic light-blocking material and / or an inorganic light-blocking material containing black pigments and / or black dyes.

[0128] Reference Figure 4 , in an embodiment, the optical control member OSL may further include a low refractive index layer LR. The low refractive index layer LR may be between the optical control elements CCP-R, CCP-G, and CCP-B and the color filters CF1, CF2, and CF3, and thus can be used as an optical functional layer for, for example, increasing the light extraction efficiency of the light emitted in the optical control layer CCL, and / or preventing or reducing the incidence of the light reflected on the optical control layer CCL into the low refractive index layer LR. The low refractive index layer LR may be a layer having a relatively low refractive index compared to the refractive indices of adjacent layers.

[0129] The low refractive index layer LR may include at least one inorganic layer. For example, the low refractive index layer LR may be formed of a material including silicon nitride, aluminum nitride, zirconium nitride, titanium nitride, hafnium nitride, tantalum nitride, silicon oxide, aluminum oxide, titanium oxide, tin oxide, cerium oxide, silicon oxynitride, and / or a metal thin film that ensures light transmittance. However, the embodiments of the present disclosure are not limited thereto, and the low refractive index layer LR may include an organic film. The low refractive index layer LR may have a structure in which a plurality of hollow particles are dispersed in an organic polymer resin, for example. The low refractive index layer LR may be configured to include a single layer or multiple layers.

[0130] The display device DD according to an embodiment may include: a bottom panel including a display layer DP-ED and a top panel (optical control member OSL) including an optical control layer CCL and a color filter layer CFL, and in an embodiment, a filling layer FML may be between the bottom panel and the top panel. In an embodiment, the filling layer FML may be filled between the display layer DP-ED and the optical control member OSL. The filling layer FML may be directly on the encapsulation layer TFE, and a second isolation layer CAP2 may be directly on the filling layer FML. The bottom surface of the filling layer FML may contact the top surface of the encapsulation layer TFE, and the top surface of the filling layer FML may contact the bottom surface of the second isolation layer CAP2.

[0131] The filling layer FML can be used as a buffer between the display layer DP-ED of the bottom panel and the optical control layer CCL of the top panel. In an embodiment, the filling layer FML can be used to absorb impacts, etc., and can increase the strength of the display device DD. The filling layer FML can be formed of a filling resin including a polymer resin. For example, the filling layer FML can be formed of a filling resin including an acrylic resin (also referred to as a polyacrylic resin or an acrylic organic material) and / or an epoxy resin, etc.

[0132] In an embodiment, Figure 3 and Figure 4 The structure of each component in the display device DD illustrated in is an example, but the embodiments of the present disclosure are not limited thereto. For example, in the optical control member OSL, the base substrate BL can be omitted and / or the filling layer FML can be omitted. The configuration of the optical control layer CCL and / or the color filter layer CFL can be different, and / or in addition to the illustrated configuration, the optical control member OSL can further include additional optical functional layers.

[0133] Reference Figure 3 and Figure 4 , in the pixel defining layer PDL of the display layer DP-ED, a light emitting opening OH is defined. The light emitting opening OH of the pixel defining layer PDL can expose at least a part of the first electrode EL1. In an embodiment, the emission regions EA1, EA2, and EA3 can be defined by the light emitting opening OH.

[0134] The pixel defining layer PDL can be formed of a polymer resin. For example, the pixel defining layer PDL can be formed by including a polyacrylic resin and / or a polyimide resin. In an embodiment, in addition to the polymer resin, the pixel defining layer PDL can be formed by further including an inorganic material. In an embodiment, the pixel defining layer PDL can be formed by including a light absorbing material and / or including a black pigment and / or a black dye. The pixel defining layer PDL formed by including a black pigment and / or a black dye can implement a black pixel defining layer. When forming the pixel defining layer PDL, carbon black, etc. can be used as the black pigment and / or the black dye, but the embodiments of the present disclosure are not limited thereto.

[0135] In an embodiment, the pixel defining layer PDL can be formed of an inorganic material. For example, the pixel defining layer PDL can be formed of an inorganic material (such as, silicon nitride (SiN x ), silicon oxide (SiO x ), and / or silicon oxynitride (SiO x N y ))

[0136] Reference Figure 3 and Figure 4, the display device DD may include a first emission region EA1, a second emission region EA2, and a third emission region EA3. The first emission region EA1, the second emission region EA2, and the third emission region EA3 may be regions separated by a pixel defining layer PDL. The first emission region EA1, the second emission region EA2, and the third emission region EA3 may respectively correspond to a first pixel region PXA-R, a second pixel region PXA-G, and a third pixel region PXA-B. In an embodiment, as used herein, the term "correspond" means that two components overlap when observed in a third direction DR3 of the display device DD, and is not limited to two components having the same area.

[0137] The emission regions EA1, EA2, and EA3 may respectively overlap with the pixel regions PXA-R, PXA-G, and PXA-B. When observed in a plane, the areas of the pixel regions PXA-R, PXA-G, and PXA-B separated by the segmentation pattern BMP may be larger than the areas of the emission regions EA1, EA2, and EA3 separated by the pixel defining layer PDL.

[0138] In the display device DD according to an embodiment, the light emitting element OEL may generate source light. In an embodiment, the source light may be white light or blue light. In an embodiment, the display layer DP-ED may include a light emitting diode as the light emitting element OEL. The emission structure ST included in the light emitting element OEL may include an organic emission material and / or an inorganic emission material as an emission material.

[0139] The light emitting element OEL includes a first electrode EL1, a second electrode EL2 facing the first electrode EL1, and an emission structure ST between the first electrode EL1 and the second electrode EL2. In an embodiment, the light emitting element OEL includes a capping layer CPL on the second electrode EL2. The capping layer CPL includes a first capping layer CPL1 and a second capping layer CPL2 stacked and separated in a thickness direction.

[0140] The display layer DP-ED may include a packaging layer TFE that protects the light emitting element OEL. The packaging layer TFE may include an organic material and / or an inorganic material. The packaging layer TFE may have a multi-layer structure in which an inorganic layer / organic layer repeats. In an embodiment, the packaging layer TFE may include a first inorganic layer IOL1, an organic layer OL, and a second inorganic layer IOL2 stacked in sequence. However, the layers constituting the packaging layer TFE are not limited thereto. The packaging layer TFE may be directly provided on the light emitting element OEL in a continuous process.

[0141] In an embodiment, the packaging layer TFE may be directly on the capping layer CPL. The packaging layer TFE may be directly on the second capping layer CPL2.

[0142] The first inorganic layer IOL1 and the second inorganic layer IOL2 can protect the light-emitting element OEL from moisture and oxygen, and the organic layer OL can protect the light-emitting element OEL from foreign substances (such as dust particles). For example, the organic layer OL can prevent or reduce defects caused by scratches in the light-emitting element OEL due to foreign substances introduced during the manufacturing process. In an embodiment, the display device DD can further include a refractive index control layer placed on the encapsulation layer TFE to improve the light extraction efficiency.

[0143] The inorganic layers IOL1 and IOL2 can include at least one of silicon nitride, silicon oxynitride, silicon oxide, titanium oxide, and aluminum oxide. The organic layer OL can include an acrylic organic material. However, the types (or kinds) of materials constituting the inorganic layers IOL1 and IOL2 and the organic layer OL are not limited thereto.

[0144] In the display device DD according to an embodiment, the display layer DP-ED can be a self-emitting type (or kind) of display layer. For example, the display layer DP-ED can include a micro-LED display layer, a nano-LED display layer, an organic emission display layer, and / or a quantum dot emission display layer. However, this is for illustrative purposes, and the display layer DP-ED is not limited thereto as long as the display element realizes a self-emitting type (or kind) of display layer.

[0145] The organic emission display layer can include: an organic electroluminescent element including an organic emission material. The quantum dot emission display layer can include: an emission layer including quantum dots and / or quantum rods. The micro-LED display layer can include micro-light emitting diode elements as ultra-small light-emitting elements, and the nano-LED display layer can include nano-light emitting diode elements. Hereinafter, the display layer DP-ED is described as an organic emission display layer. However, the configurations other than the emission layer can be similarly applied to the structures of other display layers other than the organic emission display layer.

[0146] The first electrode EL1 of the light-emitting element OEL according to an embodiment is on the circuit layer DP-CL. The first electrode EL1 can be directly or indirectly connected to the transistor T-D, and Figure 3 the connection structure between the first electrode EL1 and the transistor T-D is not illustrated. The first electrode EL1 can be an anode or a cathode. In an embodiment, the first electrode EL1 can be a pixel electrode. The first electrode EL1 can be a transmissive electrode, a transflective electrode, or a reflective electrode.

[0147] The second electrode EL2 may be on the first electrode EL1. The second electrode EL2 may be a cathode or an anode. In an embodiment, if the first electrode EL1 is a cathode, the second electrode EL2 may be an anode, and if the first electrode EL1 is an anode, the second electrode EL2 may be a cathode. The second electrode EL2 may be a common electrode. However, embodiments of the present disclosure are not limited thereto. The second electrode EL2 may be a transmissive electrode, a transmissive-reflective electrode, or a reflective electrode.

[0148] The emission structure ST may include at least one emission unit. In an embodiment, the emission structure ST of the light-emitting element OEL may include one emission unit, or may be provided in a stacked form of a plurality of emission units. If the emission structure ST is in a stacked form of a plurality of emission units, the emission structures ST may be distinguishable from each other and may include two or more emission units stacked in a third direction DR3 as a thickness direction. In an embodiment, each emission unit may include a plurality of functional layers. In an embodiment, each emission unit may include at least one emission layer as a functional layer.

[0149] In an embodiment, the emission structure ST may be provided to overlap with the pixel regions PXA-R, PXA-G, and PXA-B. In an embodiment, the emission structure ST may be provided in the pixel regions PXA-R, PXA-G, and PXA-B at the same time. The emission structure ST may be a structure in which a plurality of functional layers are stacked, and in an embodiment, all of the plurality of functional layers included in the emission structure ST may be provided in the entire pixel regions PXA-R, PXA-G, and PXA-B at the same time.

[0150] However, embodiments of the present disclosure are not limited thereto. For each of the first to third pixel regions PXA-R, PXA-G, and PXA-B, at least one functional layer constituting the emission structure ST may be formed separately. In an embodiment, at least one functional layer may be patterned in the light-emitting opening OH and formed separately for each of the first to third pixel regions PXA-R, PXA-G, and PXA-B.

[0151] The light-emitting element OEL according to an embodiment includes a capping layer CPL on the second electrode EL2. The capping layer CPL may include a plurality of layers sequentially on the second electrode EL2. The light-emitting element OEL according to an embodiment may include a first capping layer CPL1 on the second electrode EL2 and a second capping layer CPL2 on the first capping layer CPL1. The second capping layer CPL2 may be directly on the first capping layer CPL1. The first capping layer CPL1 may be directly on the second electrode EL2.

[0152] The first capping layer CPL1 and the second capping layer CPL2 may have different refractive indices. The first compound included in the first capping layer CPL1 and the second compound included in the second capping layer CPL2 may have different refractive indices. The first capping layer CPL1 may include a first compound having a high refractive index, and the second capping layer CPL2 may include a second compound having a relatively low refractive index compared to the first compound included in the first capping layer CPL1. In an embodiment, in addition to the first compound having a high refractive index, the first capping layer CPL1 may include a metal dopant.

[0153] In the capping layer CPL according to an embodiment, the metal dopant of the first capping layer CPL1 may absorb some light reflected from the first electrode EL1 or the second electrode EL2. In an embodiment, a stacked structure including the first capping layer CPL1 having a high refractive index and the second capping layer CPL2 having a low refractive index may be included, and thus destructive interference of the light reflected from the first electrode EL1 or the second electrode EL2 may be achieved through the capping layer CPL. The light directly incident on the capping layer CPL from the electrodes EL1, EL2 and the light refracted and incident at the boundary between the two capping layers CPL1, CPL2 generate destructive interference. Therefore, in the light-emitting element OEL according to an embodiment including the capping layer CPL according to the embodiment, the reflectance for external light may be reduced. In an embodiment, in the display device DD according to an embodiment including the capping layer CPL according to the embodiment, the reflectance for external light may be reduced, and thus the display device DD can exhibit excellent display quality.

[0154] Hereinafter, reference will be made to Figures 5 to 6B describe the light-emitting element included in the display device DD according to an embodiment. Figure 5 and Figure 6A are cross-sectional views of the light-emitting element according to an embodiment, respectively. Figure 6B is Figure 6A a cross-sectional view of the emission unit according to an embodiment included in

[0155] Figure 5 The light-emitting element OEL according to an embodiment illustrated in Figure 6A corresponds to an embodiment including one emission unit, and

[0156] In Figure 5 and Figure 6AIn the embodiments described, the first electrode EL1 of the light-emitting elements OEL and OEL-1 may be formed of a metal material, a metal alloy, and / or a conductive compound (e.g., a conductive compound). The first electrode EL1 may be an anode or a cathode. However, the embodiments of the present disclosure are not limited thereto. In an embodiment, the first electrode EL1 may be a pixel electrode. The first electrode EL1 may be a transmissive electrode, a transmissive-reflective electrode, or a reflective electrode. The first electrode EL1 may include at least one selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF, Mo, Ti, W, In, Sn, and Zn, a compound of two or more selected therefrom, a mixture of two or more selected therefrom, and oxides thereof.

[0157] If the first electrode EL1 is a transmissive electrode, the first electrode EL1 may include a transparent metal oxide (e.g., indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), and / or indium tin zinc oxide (ITZO)). If the first electrode EL1 is a transmissive-reflective electrode or a reflective electrode, the first electrode EL1 may include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, Mo, Ti, W, and / or a compound thereof (e.g., LiF) and / or a mixture thereof (e.g., a mixture of Ag and Mg), or a material having a multilayer structure (e.g., LiF / Ca (a stacked structure of LiF and Ca) or LiF / Al (a stacked structure of LiF and Al)). In an embodiment, the first electrode EL1 may have a multilayer structure that includes a reflective film or a transmissive-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), and / or indium tin zinc oxide (ITZO), etc. For example, the first electrode EL1 may have a three-layer structure of ITO / Ag / ITO, but is not limited thereto. In an embodiment, the embodiments of the present disclosure are not limited thereto, and the first electrode EL1 may include the above metal materials, a combination of two or more metal materials selected from the above metal materials, and / or oxides of the above metal materials, etc. The first electrode EL1 may have a thickness of about to about . For example, the first electrode EL1 may have a thickness of about to about .

[0158] The emission structure ST may include a hole transport region HTR, an emission layer EML, and an electron transport region ETR as functional layers. In Figure 5 , the emission layer EML is illustrated as one layer, but is illustrated for illustrative purposes, and the emission layer EML may have a structure in which a single layer or multiple layers are stacked.

[0159] The hole transport region HTR can be between the first electrode EL1 and the emission layer EML. In Figure 5 it, the hole transport region HTR is interpreted to include a hole injection layer HIL and a hole transport layer HTL, but embodiments of the present disclosure are not limited thereto, at least one of the hole injection layer HIL and the hole transport layer HTL can be omitted, and / or in addition to the hole injection layer HIL and the hole transport layer HTL, an emission assisting layer and an electron blocking layer can be further included.

[0160] The hole transport region HTR can have a single layer formed of a single material, a single layer formed of multiple different materials, or a multilayer structure having multiple layers formed of multiple different materials.

[0161] For example, the hole transport region HTR can have a single layer structure of a hole injection layer HIL or a hole transport layer HTL, or can have a single layer structure formed of a hole injection material and a hole transport material. In an embodiment, the hole transport region HTR can have a structure of a single layer formed of multiple different materials, or can have a structure of a hole injection layer HIL / hole transport layer HTL, a hole injection layer HIL / emission assisting layer, a hole transport layer HTL / emission assisting layer, a hole transport layer HTL / electron blocking layer, a hole injection layer HIL / hole transport region HTL / emission assisting layer, or a hole injection layer HIL / hole transport layer HTL / electron blocking layer sequentially stacked from the first electrode EL1. However, embodiments of the present disclosure are not limited thereto. In an embodiment, the hole transport layer HTL can have a single layer, or can have a multilayer structure (having multiple layers).

[0162] The hole transport region HTR can include carbazole derivatives (such as N-phenylcarbazole and / or polyvinylcarbazole), fluorene derivatives, and / or triphenylamine derivatives (such as N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD), 4,4',4''-tris(N-carbazolyl)triphenylamine (TCTA), N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine (NPB), 4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl)aniline] (TAPC), 4,4'-bis[N,N'-(3-tolyl)amino]-3,3'-dimethylbiphenyl (HMTPD), and / or 1,3-bis(N-carbazolyl)benzene (mCP)), etc.

[0163] In an embodiment, the hole transport region HTR can include 9-(4-tert-butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole (CzSi), 9-phenyl-9H-3,9'-bicarbazole (CCP), and / or 1,3-bis(1,8-dimethyl-9H-carbazol-9-yl)benzene (mDCP), etc.

[0164] In addition to the above materials, the hole transport region HTR may further include a charge generation material for improving conductivity (e.g., electrical conductivity). The charge generation material may be, for example, a p-dopant. The p-dopant may include at least one of metal halides, quinone derivatives, metal oxides, and cyano-containing compounds, but is not limited thereto. For example, the p-dopant may include: metal halides (such as CuI and / or RbI); quinone derivatives (such as tetracyanoquinodimethane (TCNQ) and / or 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ)); metal oxides (such as tungsten oxide and / or molybdenum oxide); and / or cyano-containing compounds (such as dipyrazino[2,3-f:2’,3’-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN) and / or 4-[[2,3-bis[cyano-(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropylidene]-cyanomethyl]-2,3,5,6-tetrafluorobenzonitrile (NDP9)), but the embodiments of the present disclosure are not limited thereto.

[0165] For example, in an embodiment, the hole transport region HTR may include at least one of the following compounds NPB and compound TCTA.

[0166]

[0167] In the light-emitting element OEL according to an embodiment, the emission layer EML may be provided on the hole transport region HTR. The emission layer EML may have, for example, about to about or about to about thickness. The emission layer EML may include an emission material. The emission layer EML may have a single layer formed of a single material, a single layer formed of a plurality of different materials, or a multilayer structure having a plurality of layers formed of a plurality of different materials. The emission layer EML may contain a fluorescent material and / or a phosphorescent material. In the light-emitting element OEL according to an embodiment, the emission layer EML may include an organic emission material, an organometallic complex, and / or a quantum dot, etc. as the emission material.

[0168] In the light-emitting element OEL according to an embodiment, the emission layer EML may include anthracene derivatives, pyrene derivatives, fluoranthene derivatives, 1,2-benzophenanthrene derivatives, dihydrobenzanthracene derivatives, and / or triphenylene derivatives. In an embodiment, the emission layer EML may include anthracene derivatives and / or pyrene derivatives.

[0169] The emission layer EML may include a host and a dopant. For example, the emission layer EML may include at least one of bis(4-(9H-carbazol-9-yl)phenyl)diphenylsilane (BCPDS), (4-(1-(4-(diphenylamino)phenyl)cyclohexyl)phenyl)diphenyl-phosphine oxide (POPCPA), bis[2-(diphenylphosphino)phenyl]ether oxide (DPEPO), 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP), 1,3-bis(N-carbazolyl)benzene (mCP), 2,8-bis(diphenylphosphoryl)dibenzofuran (PPF), 4,4',4''-tris(N-carbazolyl)triphenylamine (TCTA), and 1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene (TPBi). However, embodiments of the present disclosure are not limited thereto, and for example, tris(8-hydroxyquinoline)aluminum (Alq3), 9,10-bis(naphthalen-2-yl)anthracene (ADN), 2-tert-butyl-9,10-bis(naphthalen-2-yl)anthracene (TBADN), distyrylarylene (DSA), 4,4'-bis(9-carbazolyl)-2,2'-dimethyl-biphenyl (CDBP), 2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN), hexaphenylcyclotriphosphazene (CP1), 1,4-bis(triphenylsilyl)benzene (UGH2), hexaphenylcyclotrisiloxane (DPSiO3), and / or octaphenylcyclotetrasiloxane (DPSiO4), etc. can be used as host materials.

[0170] In an embodiment, the emission layer EML may include styryl derivatives (e.g., 1,4-bis[2-(3-N-ethylcarbazolyl)vinyl]benzene (BCzVB), 4-(di-p-tolylamino)-4'-[(di-p-tolylamino)styryl]stilbene (DPAVB), N-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl)naphthalen-2-yl)vinyl)phenyl)-N-phenylaniline (N-BDAVBi), and 4,4'-bis[2-(4-(N,N-diphenylamino)phenyl)vinyl]biphenyl (DPAVBi)), perylene and / or its derivatives (e.g., 2,5,8,11-tetra-tert-butylperylene (TBP)), pyrene and / or its derivatives (e.g., 1,1'-dipyrene, 1,4-dipyrenylbenzene, and / or 1,4-bis(N,N-diphenylamino)pyrene), etc. as dopant materials.

[0171] The emission layer EML may further include any suitable phosphorescent dopant materials commonly used in the art. In an embodiment, metal complexes containing iridium (Ir), platinum (Pt), osmium (Os), gold (Au), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), and / or thulium (Tm) may be used as the phosphorescent dopant materials. In an embodiment, bis(4,6-difluorophenylpyridinato-N,C2’) iridium(III) picolinate (FIrpic), bis(2,4-difluorophenylpyridinato)-tetrakis(1-pyrazolyl) borate iridium(III) (FIr6), and / or platinum octaethylporphyrin (PtOEP) may be used as the phosphorescent dopant materials. However, the embodiments of the present disclosure are not limited thereto.

[0172] For example, the emission layer EML according to an embodiment may include the following compound H1 as a host and the following compound D1 as a dopant. However, the embodiments of the present disclosure are not limited thereto.

[0173]

[0174] In an embodiment, the emission layer EML may include a quantum dot material. The description of the quantum dot material for the above optical control layer CCL( Figure 4 ) may be similarly applied to the quantum dot material included in the emission layer EML.

[0175] In the light-emitting element OEL according to an embodiment, the electron transport region ETR may be provided on the emission layer EML. The electron transport region ETR may include at least one of an electron transport layer ETL and an electron injection layer EIL, but the embodiments of the present disclosure are not limited thereto. In addition to the electron transport layer ETL and the electron injection layer EIL, the electron transport region ETR may further include a hole blocking layer. The electron transport region ETR may have a single layer formed of a single material, a single layer formed of a plurality of different materials, or a multi-layer structure having a plurality of layers formed of a plurality of different materials.

[0176] For example, the electron transport region ETR may have a single layer structure of an electron injection layer EIL or an electron transport layer ETL, or may also have a single layer structure formed of an electron injection material and an electron transport material. In an embodiment, the electron transport region ETR may have a single layer structure formed of a plurality of different materials, or may have a structure of an electron transport layer ETL / electron injection layer EIL or a hole blocking layer / electron transport layer ETL / electron injection layer EIL in which each layer is stacked in sequence, but is not limited thereto. The electron transport region ETR may have, for example, about to about in thickness.

[0177] The electron transport region (ETR) may include anthracene compounds. However, embodiments of the present disclosure are not limited thereto, and the electron transport region (ETR) may include, for example, tris(8-hydroxyquinoline)aluminum (Alq3), 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-dinaphthoanthracene, 1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene (TPBi), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), 3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole ( t Bu-PBD), bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-olato)aluminum (BAlq), bis(benzoquinolin-10-olato)beryllium (Bebq2), 9,10-di(naphthalen-2-yl)anthracene (ADN), 1,3-bis[3,5-bis(pyridin-3-yl)phenyl]benzene (BmPyPhB), and / or 2,4,6-tris(biphenyl-3-yl)-1,3,5-triazine (T2T); and / or 2,4,6-tris(3-(pyrimidin-5-yl)phenyl)-1,3,5-triazine (TPM-TAZ); and / or mixtures thereof.

[0178] In an embodiment, the electron transport region (ETR) may include: metal halides (such as LiF, NaCl, CsF, RbCl, RbI, CuI, and / or KI); lanthanide metals (such as Yb); and / or co-deposited materials of the above metal halides and lanthanide metals. For example, the electron transport region (ETR) may include KI:Yb, RbI:Yb, and / or LiF:Yb, etc. as co-deposited materials. In an embodiment, metal oxides (such as Li2O and / or BaO) and / or lithium 8-hydroxyquinolate (Liq), etc. may be used in the electron transport region (ETR), but embodiments of the present disclosure are not limited thereto. The electron transport region (ETR) may also be formed of a mixed material of an electron transport material and an insulating organometallic salt (for example, an electrically insulating organometallic salt). The insulating organometallic salt may be a material having a band gap of about 4 eV or greater. In an embodiment, for example, the insulating organometallic salt may include metal acetates, metal benzoates, metal acetoacetates, metal acetylacetonates, and / or metal stearates.

[0179] In addition to the above materials, the electron transport region ETR may further include at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), diphenyl(4-(triphenylsilyl)phenyl)phosphine oxide (TSPO1), and 4,7-diphenyl-1,10-phenanthroline (Bphen), but embodiments of the present disclosure are not limited thereto.

[0180] For example, in an embodiment, the electron transport region ETR may include at least one of the following compounds. However, embodiments of the present disclosure are not limited thereto.

[0181]

[0182] The second electrode EL2 may be provided on the electron transport region ETR. The second electrode EL2 may be a common electrode. The second electrode EL2 may be a transmissive electrode, a transmissive-reflective electrode, or a reflective electrode. If the second electrode EL2 is a transmissive electrode, the second electrode EL2 may be formed of a transparent metal oxide (such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), and / or indium tin zinc oxide (ITZO), etc.).

[0183] If the second electrode EL2 is a transmissive-reflective electrode or a reflective electrode, the second electrode EL2 may include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, Mo, Ti, Yb, W, and / or a compound including the same (such as LiF) or a mixture (such as AgMg, AgYb, or MgYb), or a material having a multilayer structure (such as LiF / Ca (a stacked structure of LiF and Ca) or LiF / Al (a stacked structure of LiF and Al)). In an embodiment, the second electrode EL2 may have a multilayer structure including a reflective film or a transmissive-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), and / or indium tin zinc oxide (ITZO), etc. For example, the second electrode EL2 may include the above metal materials, a combination of two or more of the above metal materials, and / or an oxide of the above metal materials, etc.

[0184] In the light-emitting element OEL according to an embodiment, the emission structure ST may emit blue light. However, embodiments of the present disclosure are not limited thereto, and the emission structure ST may emit light other than blue light depending on the emission material included in the emission layer EML of the emission structure ST.

[0185] In Figure 4In the display device DD according to an embodiment, some emission structures ST for patterning and providing light-emitting elements OEL may be provided to correspond to a first emission region EA1, a second emission region EA2, and a third emission region EA3, respectively. In an embodiment, an emission layer EML in a functional layer constituting the emission structure ST may be separated by a pixel defining layer PDL( Figure 4 ) so as to correspond to the emission regions EA1, EA2, and EA3( Figure 4 ) of the display layer DP-ED( Figure 4 ). In an embodiment, the emission layer EML corresponding to each of the first emission region EA1, the second emission region EA2, and the third emission region EA3 may emit light in different wavelength regions. However, embodiments of the present disclosure are not limited thereto, and even when the emission layer EML is separately provided in the emission regions EA1, EA2, and EA3( Figure 4 ), the emission layer EML may emit light in the same wavelength region.

[0186] A hole transport region HTR and an electron transport region ETR in the emission structure ST may be provided as a common layer so as to overlap with the entire first to third pixel regions PXA-R, PXA-G, and PXA-B( Figure 4 ). However, embodiments of the present disclosure are not limited thereto, and at least one of the hole transport region HTR and the electron transport region ETR may be separately patterned so as to include a separated portion in the peripheral region NPXA.

[0187] A capping layer CPL may be on a second electrode EL2 of the light-emitting element OEL according to an embodiment. The capping layer CPL may overlap with the entire first to third pixel regions PXA-R, PXA-G, and PXA-B( Figure 4 ). A first capping layer CPL1 and a second capping layer CPL2 may be sequentially on the second electrode EL2 and may be provided in the form of a common layer over the entire first to third pixel regions PXA-R, PXA-G, and PXA-B( Figure 4 ), respectively.

[0188] In an embodiment, the first capping layer CPL1 may include a first compound having a first refractive index of about 1.9 or greater at a wavelength of about 550 nm. In an embodiment, the first capping layer CPL1 may include a metal dopant having an absorption rate of about 40% or greater at a wavelength of about 550 nm and the first compound. The first compound and the metal dopant may be provided by co-deposition to form the first capping layer CPL1.

[0189] The first compound may be an organic compound. In the first capping layer CPL1, the first compound may be a main component, and for example, the first compound may be referred to as a host material in the first capping layer CPL1. For example, the light-emitting element OEL according to an embodiment may include the following compound CPM1 as the first compound in the first capping layer CPL1. However, the embodiments of the present disclosure are not limited thereto, and any suitable organic material having a high refractive index of about 1.9 or greater at a wavelength of about 550 nm may be used as the first compound without limitation.

[0190]

[0191] The metal dopant contained in the first capping layer CPL1 may be selected from alkali metals, alkaline earth metals, lanthanide metals, and / or transition metals. The metal dopant contained in the first capping layer CPL1 may be an alkali metal, an alkaline earth metal, a lanthanide metal, and / or a transition metal, and may have an absorption rate of about 40% or greater at a wavelength of about 550 nm. For example, the metal dopant contained in the first capping layer CPL1 may be lithium (Li) and / or ytterbium (Yb). However, the embodiments of the present disclosure are not limited thereto, and any suitable metal material having an absorption rate of about 40% or greater and capable of absorbing some of the provided light may be used as the metal dopant contained in the first capping layer CPL1 without limitation.

[0192] In the first capping layer CPL1, the volume ratio (vol%) of the first compound to the metal dopant may be from about 99:1 to about 95:5. In the first capping layer CPL1, when the volume ratio of the metal dopant is less than about 1 vol%, the light absorption of the metal dopant is insufficient, and thus the improvement effect on the reflectance of external light is not shown or the improvement effect on the reflectance of external light is insufficient. In an embodiment, when the volume ratio of the metal dopant in the first capping layer CPL1 is greater than about 5 vol%, the light absorption rate of the first capping layer CPL1 increases, and thus the luminous efficiency of the light-emitting element OEL may be reduced.

[0193] The first capping layer CPL1 may have a thickness t of about to about . The first capping layer CPL1 has a thickness of about CP1 . The first capping layer CPL1 has a thickness of about to about so as to exhibit the effect of reducing the reflectance of external light without reducing the luminous efficiency. The first capping layer CPL1 having a thickness of about to about may be provided in a stacked structure with the second capping layer CPL2 to be further described herein. Therefore, destructive interference that cancels the reflection of external light can be induced.

[0194] In an embodiment, in the present specification, the evaluation includes each of the specular component (SCI) reflectance and the specular component excluded (SCE) reflectance as the reflectance for external light. As used herein, an improvement in the reflectance for external light corresponds to a case where both the SCI reflectance and the SCE reflectance are improved.

[0195] The second capping layer CPL2 may be directly on the first capping layer CPL1 and may have a second refractive index less than the first refractive index of the first capping layer CPL1. At a wavelength of about 550 nm, the difference between the first refractive index and the second refractive index may be about 0.2 or greater.

[0196] The capping layer CPL may be between the second electrode EL2 and the encapsulation layer TFE( Figure 4 ) and may have a stacked structure of a first capping layer CPL1 having a high refractive index and a second capping layer CPL2 having a low refractive index, respectively. The difference between the first refractive index of the first capping layer CPL1 and the second refractive index of the second capping layer CPL2 may be about 0.2 or greater, and thus the light-emitting element OEL may have the characteristic of reduced reflectance for external light. The stacked structure including the first capping layer CPL1 and the second capping layer CPL2 having the above optical characteristics, and thus due to destructive interference, the reflected light reflected from the first electrode EL1 or the second electrode EL2 toward the outside may be reduced.

[0197] The second capping layer CPL2 may include a second compound having a second refractive index less than the first refractive index. The second refractive index may be about 1.4 to about 1.7.

[0198] The second compound may be an organic compound and / or an inorganic compound. For example, the second capping layer CPL2 in which the second compound is an inorganic compound may include: an alkali metal compound (such as, LiF); an alkaline earth metal compound (such as, MgF2); SiON; SiN X ; and / or SiO y and the like.

[0199] For example, when the second compound is an organic compound, the second capping layer CPL2 may include N'-bis(naphthalen-1-yl)-N,N'-di(phenyl)-2,2'-dimethylbenzidine (α-NPD), NPB, TPD, 4,4',4''-[tris(3-methylphenyl)phenylamino]triphenylamine (m-MTDATA), Alq3, CuPc, N4,N4,N4',N4'-tetrakis(biphenyl-4-yl)biphenyl-4,4'-diamine (TPD15) and / or 4,4',4''-tris(carbazol-9-yl)triphenylamine (TCTA) and the like, and / or may include an epoxy resin and / or an acrylate (such as, methacrylate).

[0200] In an embodiment, the second capping layer CPL2 may include the following compound CPM2-1 and / or compound CPM2-2. However, embodiments of the present disclosure are not limited thereto, and organic materials and / or inorganic materials having a low refractive index of about 1.7 or less at a wavelength of about 550 nm may be used as the second compound without limitation.

[0201]

[0202] The second capping layer CPL2 may have a thickness t of about to about . Since the second capping layer CPL2 has a thickness of about CP2 , an effect of reduced reflectivity for external light can be exhibited without reducing the luminous efficiency. A second capping layer CPL2 having a thickness of about to about may be provided on the first capping layer CPL1 to induce destructive interference that cancels out the emitted light reflected on the bottom of the capping layer CPL. to about

[0203] The light-emitting element OEL according to an embodiment may include: a first capping layer CPL1 including a first compound having a high refractive index and a metal dopant; and a second capping layer CPL2 on the first capping layer CPL1 and including a second compound having a refractive index lower than that of the first compound, thereby showing improved optical characteristics of reduced reflectivity for external light. In an embodiment, in the light-emitting element OEL according to the embodiment, the stacked structure of the first capping layer CPL1 and the second capping layer CPL2 is on the second electrode EL2, and thus excellent luminous efficiency characteristics can be exhibited. Figure 5 The light-emitting element OEL according to the embodiment illustrated in Figure 4 may be included in the display device DD according to the embodiment described with reference to FIGS. 1 to

[0204] Figure 6A , and since the reflectivity for external light is reduced, the display device DD according to the embodiment may exhibit excellent display quality. Figure 6A In

[0205] Reference Figure 6A and Figure 6B The light-emitting element OEL-1 according to an embodiment may be included in the display layer DP-ED ( Figure 4 ) of the display device DD according to the embodiment described with reference to FIGS. 1 to Figure 4 . In the light-emitting element OEL-1 according to the embodiment described with reference to Figure 6A and Figure 6B , the content same as that of the light-emitting element OEL described in Figure 5 will not be described again, and the differences will be mainly described.

[0206] The light-emitting element OEL-1 according to an embodiment may include a first emission unit EU-1, a second emission unit EU-2, and a third emission unit EU-3 stacked in sequence. At least one of the emission units EU-1, EU-2, and EU-3 may emit blue light. The first to third emission units EU-1, EU-2, and EU-3 may all emit blue light, at least one of the first to third emission units EU-1, EU-2, and EU-3 may emit green light, and the remaining ones may emit blue light, or each of the first to third emission units EU-1, EU-2, and EU-3 may emit light in different wavelength regions from each other.

[0207] In Figure 6A the embodiment illustrated, the light generated in the light-emitting element OEL-1 may be emitted in the direction of the top surface of the capping layer CPL (e.g., in the third direction DR3).

[0208] The light-emitting element OEL-1 according to an embodiment may include charge generation layers CGL-1 and CGL-2 between the plurality of emission units EU-1, EU-2, and EU-3. The light-emitting element OEL-1 according to an embodiment may include a first charge generation layer CGL-1 between the first emission unit EU-1 and the second emission unit EU-2, and a second charge generation layer CGL-2 between the second emission unit EU-2 and the third emission unit EU-3.

[0209] When a voltage is applied to the light-emitting element OEL-1, the charge generation layers CGL-1 and CGL-2 form a complex through a redox reaction, and thus charges (electrons and holes) may be generated. In the embodiment, the charge generation layers CGL-1 and CGL-2 may provide the generated charges to each of the adjacent emission units EU-1, EU-2, and EU-3. The charge generation layers CGL-1 and CGL-2 may increase the efficiency of the current generated in each of the adjacent emission units EU-1, EU-2, and EU-3, and may be used to control the balance of charges between the emission units EU-1, EU-2, and EU-3.

[0210] The charge generation layers CGL-1 and CGL-2 may each have a layer structure in which an n-type charge generation layer n-CGL and a p-type charge generation layer p-CGL are combined with each other.

[0211] The n-type charge generation layer n-CGL may supply electrons to adjacent emission units EU-1, EU-2, and EU-3. The n-type charge generation layer n-CGL may be a layer in which a base material is doped with an n-dopant. The p-type charge generation layer p-CGL may supply holes to adjacent emission units EU-1, EU-2, and EU-3. The p-type charge generation layer p-CGL may be a layer in which a base material is doped with a p-dopant.

[0212] In an embodiment, a buffer layer (not shown) may be further provided between the n-type charge generation layer n-CGL and the p-type charge generation layer p-CGL.

[0213] The charge generation layers CGL-1 and CGL-2 may respectively include an n-type arylamine material and / or may include a p-type metal oxide. For example, each of the charge generation layers CGL-1 and CGL-2 may include a charge generation compound made of an arylamine organic compound, a metal, an oxide, carbonate, or fluoride of the metal, or a mixture thereof.

[0214] For example, the arylamine organic compound may be α-NPD, 4,4’,4”-tris[N-(2-naphthyl)-N-phenylamino]triphenylamine (2-TNATA), 4,4’,4”-tris(N,N-diphenylamino)triphenylamine (TDATA), MTDATA, 2,2’,7,7’-tetrakis(N,N-diphenylamino)-2,7-diamino-9,9-spirobifluorene (SpiroTAD), and / or N,N’-bis(naphthalen-1-yl)-N,N’-bis(phenyl)-2,7-diamino-9,9-spirobifluorene (SpiroNPB). For example, the metal may be cesium (Cs), molybdenum (Mo), vanadium (V), titanium (Ti), tungsten (W), barium (Ba), and / or lithium (Li). In an embodiment, for example, the oxides, carbonates, and fluorides of the metal may be Re2O7, MoO3, V2O5, WO3, TiO2, Cs2CO3, BaF2, LiF, and / or CsF.

[0215] In an embodiment, the charge generation layers CGL-1 and CGL-2 may include at least one of the following compounds CGL1 to compound CGL3. However, the embodiments of the present disclosure are not limited thereto.

[0216]

[0217] In Figure 6AIn [the figure], a stacked structure of three emission units EU-1, EU-2, and EU-3 and two charge generation layers CGL-1 and CGL-2 therebetween is illustrated. However, embodiments of the present disclosure are not limited thereto, and if the number of stacked emission units increases, corresponding charge generation layers can be added between the emission units.

[0218] The multiple emission units EU-1, EU-2, and EU-3 may each include emission layers EML-1, EML-2, and EML-3. The multiple emission units EU-1, EU-2, and EU-3 may each separately include a hole transport region HTR-1, HTR-2, and HTR-3, emission layers EML-1, EML-2, and EML-3, and an electron transport region ETR-1, ETR-2, and ETR-3. In an embodiment, the light-emitting element OEL-1 according to the embodiment may be a light-emitting element having a series structure that includes multiple emission layers EML-1, EML-2, and EML-3 stacked in the thickness direction.

[0219] Reference Figure 5 The descriptions of the hole transport region HTR, emission layer EML, and electron transport region ETR described [above] can be similarly applied to the hole transport regions HTR-1, HTR-2, and HTR-3, emission layers EML-1, EML-2, and EML-3, and electron transport regions ETR-1, ETR-2, and ETR-3 included in the emission units EU-1, EU-2, and EU-3, respectively.

[0220] The multiple emission units EU-1, EU-2, and EU-3 may be included in the display layer DP-ED ( Figure 4 ) of a display device DD ( Figure 4 ) according to an embodiment. In an embodiment, the multiple emission units EU-1, EU-2, and EU-3 may be provided as a common layer throughout the first to third pixel regions PXA-R, PXA-G, and PXA-B.

[0221] In an embodiment, at least one of the multiple emission units EU-1, EU-2, and EU-3 separated by a pixel defining layer PDL ( Figure 4 ) may be patterned and provided. In an embodiment, the emission layers EML-1, EML-2, and EML-3 of the emission units EU-1, EU-2, and EU-3 may be patterned and provided so as to be separated by the pixel defining layer PDL ( Figure 4 ).

[0222] Figure 6BAn example in [the text] shows one of the emission units EU-1, EU-2, and EU-3 included in the light-emitting element OEL-1 according to an embodiment. One emission unit EU may have a stacked structure of a hole transport region HTR, an emission layer EML, and an electron transport region ETR. In the emission unit EU, the hole transport region HTR may include at least one of a hole injection layer HIL and a hole transport layer HTL, and the electron transport region ETR may include at least one of an electron transport layer ETL and an electron injection layer EIL.

[0223] In an embodiment, in the hole transport region HTR of the emission units EU-1, EU-2, and EU-3 adjacent to the charge generation layers CGL-1 and CGL-2, the hole injection layer HIL may be omitted, and / or the electron injection layer EIL may be omitted. However, the embodiments of the present disclosure are not limited thereto.

[0224] In Figure 6A In the light-emitting element OEL-1 according to an embodiment illustrated in [the text], a capping layer CPL may be on an emission structure ST-1 including a plurality of emission units EU-1, EU-2, and EU-3. The capping layer CPL may include a first capping layer CPL1 on the second electrode EL2 and a second capping layer CPL2 on the first capping layer CPL1.

[0225] For reference to FIGS. 1 to Figure 5 The description of the capping layer described [in the text] may be similarly applied to the first capping layer CPL1 and the second capping layer CPL2. In an embodiment, the light-emitting element OEL-1 according to an embodiment includes: a first capping layer CPL1 including a first compound having a high refractive index and a metal dopant; and a second capping layer CPL2 on the first capping layer CPL1 and including a second compound having a refractive index lower than that of the first compound, thereby exhibiting improved optical characteristics with reduced reflectivity of external light. In an embodiment, in the light-emitting element OEL-1 according to an embodiment, the stacked structure of the first capping layer CPL1 and the second capping layer CPL2 is on the second electrode EL2, thereby exhibiting excellent light-emitting efficiency characteristics. Figure 6A The light-emitting element OEL-1 according to an embodiment illustrated in [the text] may be included in the display device DD according to an embodiment described with reference to FIGS. 1 to Figure 4 The display device DD according to an embodiment may have reduced reflectivity of external light to exhibit excellent display quality.

[0226] Hereinafter, evaluation results of the characteristics of the display device according to an embodiment will be described with reference to examples and comparative examples. The examples shown below are only for understanding the subject matter of the present disclosure, and the scope of the present disclosure is not limited thereto.

[0227] Manufacture of the display device

[0228] The display devices according to the comparative example and the embodiment each have a structure including a display layer (the display layer includes light-emitting elements) and an optical control member on the display layer, and an anti-reflection layer including a low-reflection film on the optical control member.

[0229] Based on Figure 6A the structure of the light-emitting element OEL-1 illustrated in, the light-emitting elements used in the display devices according to the comparative example and the embodiment are manufactured.

[0230] Between the first to third emission units EU-1, EU-2, and EU-3 ( Figure 6A ), charge generation layers CGL-1 and CGL-2 ( Figure 6A ) including an n-type charge generation layer n-CGL ( Figure 6A ) and a p-type charge generation layer p-CGL ( Figure 6A ) are provided. The n-type charge generation layer n-CGL is formed by doping the above compound CGL1 with Li. On the n-type charge generation layer n-CGL, a p-type charge generation layer p-CGL is formed with 98% (volume%) of NPB and 2% (volume%) of F4-TCNQ.

[0231] The first electrode EL1 ( Figure 6A ) is formed to have a structure of ITO / Ag / ITO, and the second electrode EL2 ( Figure 6A ) is formed of AgMg. In the first to third emission units EU-1, EU-2, and EU-3 ( Figure 6A ), the hole transport region HTR ( Figure 6B ) may include a hole transport layer HTL ( Figure 6B ) formed of two stacked layers. The hole transport layer HTL ( Figure 6B ) may include a layer formed of NPB and a layer formed of TCTA stacked in sequence.

[0232] In an embodiment, the first emission unit EU-1 ( Figure 6A ) may further include a hole injection layer HIL ( Figure 6A ) provided on the first electrode EL1 ( Figure 6B ), and the hole injection layer HIL ( Figure 6A ) in the first emission unit EU-1 ( Figure 6B ) may include 95% (volume%) of NPB and 5% (volume%) of F4-TCNQ.

[0233] The emission layers in the first to third emission units EU-1, EU-2, and EU-3 ( Figure 6A ) may each include 99% (volume%) of H1 and 1% (volume%) of D1 as the above host material and dopant material, respectively.

[0234] The first to third emission units EU-1, EU-2, and EU-3 ( Figure 6A ) in the electron transport region ETR ( Figure 6B ) may include an electron transport layer ETL ( Figure 6B ) formed of two stacked layers. The electron transport layer ETL ( Figure 6B ) may be formed by including a co-deposited layer formed by adding Liq to a layer formed of T2T and a layer formed of TPM-TAZ stacked in sequence, where Liq:T2T is 50% (volume %):50% (volume %) and Liq:TPM-TAZ is 50% (volume %):50% (volume %).

[0235] In an embodiment, the third emission unit EU-3 ( Figure 6A ) may further include an electron injection layer EIL ( Figure 6A ) below the second electrode EL2 ( Figure 6B ), and the electron injection layer EIL ( Figure 6A ) in the third emission unit EU-3 ( Figure 6B ) may include Yb.

[0236] In a display device according to an embodiment, a first capping layer CPL1 ( Figure 6A ) of a light-emitting element is formed by including a compound CPM1 as a first compound and co-depositing Yb or Li. A second capping layer CPL2 ( Figure 6A ) is formed by including a compound CPM2-2 as a second compound.

[0237] The embodiments are intended to show that a display device including a first capping layer CPL1 (containing a first compound having a high refractive index characteristic and a metal dopant) and a second capping layer CPL2 (containing a second compound having a lower refractive index characteristic than the first compound) placed above the first capping layer CPL1 can exhibit optical characteristics with a reduced external light reflectance. Additionally, it can be confirmed from the embodiments that when the content of the metal dopant in the first capping layer CPL1 is between 1 volume % and 5 volume %, characteristics with a reduced reflectance can be obtained. In other words, the evaluation results of these embodiments are intended to show the effects of the laminated structure of the capping layer and the relative content ratio of the metal dopant in the capping layer, and thus a detailed description of the specific content of other components is considered unimportant.

[0238] A light-emitting element according to Comparative Example 1 is formed such that the first capping layer CPL1 ( Figure 6A ) includes a compound CPM1 as a first compound, and the second capping layer CPL2 ( Figure 6A ) includes a compound CPM2-1 as a second compound.

[0239] In the case of Comparative Example A1, compared with Example A1, the Yb content was changed to form the first capping layer CPL1 ( Figure 6A ), and in the case of Comparative Example B1, compared with Example B1 and Example B2, the Li content was changed to form the first capping layer CPL1 ( Figure 6A ).

[0240] In the cases of Comparative Example C1, Comparative Example C2, and Comparative Example C3, silver (Ag) was used as a metal dopant in the first capping layer CPL1 ( Figure 6A ), and the Ag content was changed to form the first capping layer CPL1 ( Figure 6A ).

[0241] In the light-emitting elements according to the comparative examples and examples in Table 1, the first capping layer CPL1 ( Figure 6A ) was formed to have a thickness of about , and the second capping layer CPL2 ( Figure 6A ) was formed to have a thickness of about .

[0242] In Table 2, a light-emitting element according to Comparative Example 2 was formed such that the first capping layer CPL1 ( Figure 6A ) included the first compound of CPM1, and the second capping layer CPL2 ( Figure 6A ) included the second compound of CPM2-1. In the light-emitting elements according to Comparative Example 2A, Comparative Example 2B, and Example 2, by including the compound CPM1 as the first compound and based on the total volume of the first capping layer CPL1 ( Figure 6A ), about 1.0% of Yb was co-deposited to form the first capping layer CPL1 ( Figure 6A ). The second capping layer CPL2 ( Figure 6A ) was formed by including the compound CPM2-2 as the second compound.

[0243] In the light-emitting elements according to Comparative Example 2, Comparative Example 2A, Comparative Example 2B, and Example 2, the first capping layer CPL1 was formed to have a thickness of about . In the light-emitting elements according to Comparative Example 2 and Example 2, the second capping layer CPL2 had a thickness of about , and in the light-emitting elements according to Comparative Example 2A and Comparative Example 2B, the second capping layer CPL2 had thicknesses of about and about , respectively.

[0244] In the light-emitting elements according to the comparative examples and examples listed in Table 1 and Table 2, the % of the metal dopant corresponds to the volume ratio.

[0245] The following example compounds are compounds for manufacturing light-emitting elements according to the comparative examples and examples.

[0246] Example compound

[0247]

[0248] The light absorption characteristics of the metal dopants used in the comparative examples and examples are shown in Figure 7 In Figure 7 the absorption rates of Yb, Li, and Ag used in the examples and comparative examples according to wavelength were evaluated, and the evaluation results are shown in Figure 7 In a film formed on a glass substrate using each metal dopant, the absorption rate of the light transmitted through the stacked structure of the glass substrate and the film was evaluated, and the results are shown by comparison in Figure 7 In Figure 7 the absorption rate was measured using a UV-visible spectrometer, and the film formed using the metal dopant had a thickness of about Referring to the evaluation results of the absorption rate in Figure 7 compared with the film using Ag, the films using Yb and Li exhibited the characteristic of high absorption rate in the entire measured wavelength region. The films using Yb and Li exhibited the characteristic of an absorption rate of about 40% or more throughout the visible light wavelength region, and the film using Ag exhibited the characteristic of an absorption rate of less than about 40% throughout the visible light wavelength region.

[0249] In the light-emitting elements according to the comparative examples and examples, the conditions of the remaining components except for the first capping layer CPL1 are the same.

[0250] Evaluation of the display device

[0251] The SCI reflectance and SCE reflectance of the light-emitting elements according to the comparative examples and examples were evaluated, and the results are listed in Table 1 below. The SCI reflectance and SCE reflectance were measured using CM-26Dg of Konica Minolta Inc.

[0252] In Table 1, the evaluation results of the SCI reflectance and SCE reflectance are presented as relative values. The value in the case of Comparative Example 1 was set to 100%, and all other values are expressed as relative percentages based on the value of Comparative Example 1. If the value is greater than 100%, it corresponds to the case where the light-emitting element has an increased SCI reflectance and SCE reflectance, and if the value is less than 100%, it corresponds to the case where the light-emitting element has a decreased SCI reflectance and SCE reflectance.

[0253] Table 1

[0254]

[0255] Referring to the results in Table 1, when a metal dopant having an absorption rate of about 40% or more at a wavelength of about 550 nm is included in the first capping layer CPL1 ( Figure 6A ) in an amount of about 1.0% or more, the SCI reflectance and the SCE reflectance decrease.

[0256] Compared with the light-emitting element according to Comparative Example 1 in which no metal dopant is included in the first capping layer CPL1 ( Figure 6A ), it can be seen that the light-emitting elements according to Example A1, Example A2, Example B1, and Example B2 have the characteristic of reduced reflectance for external light. That is, it can be seen that when, in addition to including the first compound having a high refractive index, a metal dopant having an absorption rate of about 40% or more at a wavelength of about 550 nm is included in the first capping layer CPL1, the reflectance for external light is improved as compared with the case where the first capping layer CPL1 does not include a metal dopant.

[0257] When the light-emitting element according to Comparative Example A1 is compared with the light-emitting elements according to Example A1 and Example A2, and the light-emitting element according to Comparative Example B1 is compared with the light-emitting elements according to Example B1 and Example B2, it can be seen that if the first capping layer CPL1 ( Figure 6A ) includes a metal dopant in an amount of about 1% or more, an effect of reduced reflectance for external light is exhibited.

[0258] When the light-emitting element according to the embodiment is compared with the light-emitting elements according to Comparative Examples C1 to C3, it can be seen that the light-emitting element according to the embodiment exhibits the characteristic of reduced reflectance for external light, but the light-emitting elements according to Comparative Examples C1 to C3 (wherein the first capping layer CPL1 ( Figure 6A ) contains Ag having a relatively low absorption rate characteristic) have a reflectance for external light similar to or greater than that of the light-emitting element according to Comparative Example 1. For example, it can be seen that even when, in addition to the first compound having a high refractive index, a metal dopant is included in the first capping layer CPL1, if a metal dopant such as Ag having an absorption rate of less than about 40% is included, the reflectance for external light is not improved.

[0259] From the results in Table 1, it can be seen that the display device according to the embodiment includes: a first capping layer CPL1 ( Figure 6A ), the first capping layer CPL1 including a first compound having a high refractive index and a metal dopant; and a second capping layer CPL2 ( Figure 6A), the second capping layer CPL2 is on the first capping layer CPL1 and includes a second compound having a low refractive index, thus exhibiting improved optical properties with reduced reflectivity for external light. From the results of the examples, the absorption rate of the metal dopant at a wavelength of about 550 nm is about 40% or more, and when the metal dopant content in the first capping layer CPL1 is about 1 vol% to about 5 vol%, a reduced reflectivity for external light is shown.

[0260] Evaluate the reflectivity characteristics for external light according to the thickness variation of the second capping layer CPL2 ( Figure 6A ), and the results are listed in Table 2 below. Measure the SCI reflectivity and SCE reflectivity of the light-emitting elements according to the comparative examples and examples in Table 2 below using the CM-26Dg of Konica Minolta Inc.

[0261] The evaluation results of the SCI reflectivity and SCE reflectivity are presented as relative values in Table 2. Set the value in the case of Comparative Example 2 to 100%, and represent all other values as relative percentages based on the value of Comparative Example 2. If the value is less than 100%, it corresponds to the case where the SCI reflectivity and SCE reflectivity are reduced.

[0262] Table 2

[0263]

[0264] Referring to the results in Table 2, when comparing the light-emitting element according to Comparative Example 2 with the light-emitting element according to Example 2, it can be seen that by adding Yb as a metal dopant to the first capping layer CPL1 ( Figure 6A ), improved optical properties with reduced reflectivity for external light can be shown.

[0265] When comparing the light-emitting elements according to Comparative Example 2A, Comparative Example 2B, and Example 2, it can be seen that in the light-emitting element according to Example 2 where the second capping layer CPL2 ( Figure 6A ) has a thickness of about , the SCI reflectivity and SCE reflectivity shown are lower than those of the light-emitting elements according to Comparative Example 2A and Comparative Example 2B. In contrast, it can be seen that in the light-emitting element according to Comparative Example 2B where the second capping layer CPL2 has a thickness of about , the SCI reflectivity and SCE reflectivity are similar to those of the light-emitting element according to Comparative Example 2A where the second capping layer CPL2 has a thickness of about . Therefore, it can be seen that when the second capping layer CPL2 has a thickness of about When the thickness is equal to or greater than a certain value, additional effects of reducing the SCI reflectance and the SCE reflectance can be shown. It is considered that the destructive interference between the external reflected light generated on the second capping layer CPL2 and the reflected light on the light-emitting element results in the effect of reducing the reflectance for external light. Therefore, as can be seen from the results in Table 1 and Table 2, the display device according to the embodiment includes: a first capping layer CPL1 ( Figure 6A ), the first capping layer CPL1 includes a first compound having a high refractive index and a metal dopant; and a second capping layer CPL2, the second capping layer CPL2 is on the first capping layer CPL1 and includes a second compound having a refractive index lower than that of the first compound, and can exhibit improved optical characteristics of reducing the reflectance for external light. From the results of the examples, it can be confirmed that when the absorption rate of the metal dopant at a wavelength of about 550 nm is about 40% or more, and the content of the metal dopant in the first capping layer CPL1 is about 1 vol% to about 5 vol%, the display device has the characteristic of reducing the reflectance for external light. In the embodiment, it can be seen that when the second capping layer CPL2 has a thickness of about or more, the effect of reducing the reflectance for external light is more obvious.

[0266] The light-emitting element according to the embodiment includes: a first capping layer stacked on the emission structure and including a material having a high refractive index and a metal dopant; and a second capping layer on the first capping layer and having a refractive index lower than that of the first capping layer, and thus can exhibit the characteristic of reducing the reflectance for external light.

[0267] The display device according to the embodiment includes a light-emitting element, the light-emitting element includes: a first capping layer including a material having a high refractive index and a metal dopant; and a second capping layer on the first capping layer and having a refractive index lower than that of the first capping layer, and thus minimizes or reduces the external light reflected by the electrodes of the light-emitting element, thereby exhibiting excellent display quality.

[0268] So far, although the subject matter of the present disclosure has been described with reference to the exemplary embodiments of the present disclosure, it will be understood that the present disclosure should not be limited to these exemplary embodiments, but various appropriate changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the present disclosure.

[0269] Accordingly, the technical scope of the present disclosure is not intended to be limited to what is stated in the detailed description of the specification, but is intended to be defined by the claims and their equivalents.

Claims

1. A light emitting element, comprising: a first electrode; a second electrode, facing the first electrode; an emitting structure between the first electrode and the second electrode; a first capping layer on the second electrode and including a first compound having a first refractive index of 1.9 or more at a wavelength of 550 nm and a metal dopant having an absorptivity of 40% or more at the wavelength of 550 nm; as well as A second capping layer is on the first capping layer and includes a second compound having a second refractive index less than the first refractive index. 2 . The light emitting element according to claim 1 , wherein a difference between the first refractive index and the second refractive index is 0.2 or more. The light-emitting element according to claim 2 , wherein the second refractive index is 1.4 to 1.

7. The light-emitting element according to claim 1 , wherein the metal dopant is an alkali metal, an alkaline earth metal, a lanthanide metal and / or a transition metal. The light-emitting element according to claim 1 , wherein the metal dopant is lithium and / or ytterbium. The light-emitting element according to claim 1 , wherein a volume ratio of the first compound to the metal dopant in the first capping layer is 99:1 to 95:

5.

7. The light-emitting element according to claim 1, wherein the thickness of the first capping layer and the thickness of the second capping layer are each independently to 8. The light emitting element according to claim 1, wherein the emitting structure comprises: an emission layer, on the first electrode; a hole transport region between the first electrode and the emission layer; and an electron transport region between the emission layer and the second electrode.

9. The light emitting element according to claim 1, wherein the emitting structure comprises: A plurality of emission units, stacked in sequence and each comprising a hole transport region, an emission layer and an electron transport region, and A charge generation layer is provided between each pair of adjacent emission units in the plurality of emission units between the first electrode and the second electrode.

10. The light-emitting element according to claim 1, wherein the emitting structure emits blue light. 11 . The light-emitting element according to claim 1 , wherein the first compound is an organic material, and the second compound is an organic material or an inorganic material.

12. A display device, comprising: The light emitting element according to any one of claims 1 to 11, emitting source light; and The optical control layer is on the light emitting element and is configured to transmit the source light or convert the wavelength of the source light.

13. The display device according to claim 12, comprising: A first pixel region emitting red light; a second pixel region emitting green light; as well as a third pixel region emitting blue light, wherein the first pixel region, the second pixel region and the third pixel region do not overlap in a plane, The optical control layer comprises: a first optical control element provided to correspond to the first pixel region and including a first quantum dot that converts the wavelength of the source light; a second optical control element provided to correspond to the second pixel region and including a second quantum dot that converts the wavelength of the source light; and A third optical control element is provided corresponding to the third pixel area.

14. A display device, comprising: Circuit layer; The light emitting element according to any one of claims 1 to 11, on the circuit layer; and The encapsulation layer is on the light emitting element. The display device of claim 14 , wherein the encapsulation layer is directly on the second capping layer.

Images