Light-emitting element

Abstract

Disclosed is a light emitting element including a first electrode, a light emitting structure disposed on the first electrode and including an emission layer, a second electrode disposed on the light emitting structure and including silver (Ag) and a metal dopant, and a cap layer disposed directly on the second electrode. An average volume ratio of the metal dopant in the second electrode is less than or equal to about 30%, and a volume ratio of the metal dopant in a region adjacent to the cap layer is less than the average volume ratio of the metal dopant in the second electrode, thereby maintaining excellent electrical and optical properties while having improved reliability.

Description

[0001] This application claims priority and the benefit of Korean Patent Application No. 10-2024-0000335, filed with the Korean Intellectual Property Office (KIPO) on January 2, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] Disclosed herein relate to a light-emitting element including an electrode having an optimized ratio of a metal dopant and a display device including the light-emitting element. Background Art

[0003] Various types of display devices are being developed for multimedia devices such as televisions, mobile phones, tablet computers, navigation systems, and gaming consoles. In a display device, a so-called self-emitting display element is used, and the self-emitting display element realizes display by causing a light-emitting material containing an organic compound or a quantum dot in an emission layer provided between electrodes facing each other to emit light.

[0004] Regarding the light-emitting element and the application of the light-emitting element in a display device, there is a need for an element having excellent electrical and optical properties and maintaining reliability even when exposed to external light for a long time. Summary of the Invention

[0005] Disclosed provides a light-emitting element having improved reliability.

[0006] Disclosed also provides a display device having improved reliability and display quality.

[0007] According to an embodiment of the disclosure, the light-emitting element may include a first electrode, a light-emitting structure provided on the first electrode and including an emission layer, a second electrode provided on the light-emitting structure and including silver (Ag) and a metal dopant, and a cover layer provided directly on the second electrode. The average volume ratio of the metal dopant in the second electrode may be less than or equal to about 30%, and the volume ratio of the metal dopant in a region adjacent to the cover layer may be less than the average volume ratio of the metal dopant in the second electrode.

[0008] In an embodiment, the metal dopant may include at least one of Al, Au, Cu, Mg, Ti, In, Ni, C, Pd, F, Na, Si, Ca, Mn, Fe, Co, Zn, Ga, Ge, Mo, Sn, In, Pt, Pb, Fe, Yb, Lu, and Pa.

[0009] In an embodiment, the metal dopant may be Mg, and the average volume ratio of the metal dopant in the second electrode may be in the range of about 3% to about 10%.

[0010] In an embodiment, the volume ratio of the metal dopant in the second electrode may gradually decrease in the direction from the light-emitting structure to the cover layer.

[0011] In an embodiment, the second electrode may have a thickness in the range of about 50 Å to about 300 Å.

[0012] In an embodiment, the second electrode may be formed by co-depositing silver and a metal dopant using a thermal evaporation method.

[0013] In an embodiment, the second electrode may include a first region, a second region, and a third region. The first region includes a first surface in contact with the cover layer, the second region includes a second surface in contact with the light-emitting structure, the third region is disposed between the first region and the second region, and a first volume ratio of the metal dopant in the first region and a second volume ratio of the metal dopant in the second region may both be less than the average volume ratio of the metal dopant in the second electrode.

[0014] In an embodiment, a third volume ratio of the metal dopant in the third region may be greater than the average volume ratio of the metal dopant in the second electrode.

[0015] In an embodiment, the third region may include: a first sub-region having a third volume ratio of the metal dopant that is less than the average volume ratio of the metal dopant in the second electrode; a second sub-region disposed between the first region and the first sub-region and having a fourth volume ratio of the metal dopant that is greater than the average volume ratio of the metal dopant in the second electrode; and a third sub-region disposed between the second region and the first sub-region and having a fifth volume ratio of the metal dopant that is greater than the average volume ratio of the metal dopant in the second electrode.

[0016] In an embodiment, the third region may include at least one sub-region having a third volume ratio of the metal dopant that is less than the average volume ratio of the metal dopant in the second electrode.

[0017] In an embodiment, the first electrode may be a reflective electrode, and the second electrode may be a transmissive electrode or a transmissive-reflective electrode.

[0018] In an embodiment, the second electrode may have a transmittance of greater than or equal to about 70% at about 550 nm.

[0019] In an embodiment, the light-emitting structure may include an emission layer, a hole transport region disposed between the first electrode and the emission layer, and an electron transport region disposed between the emission layer and the second electrode, and the electron transport region may be directly disposed under the second electrode and may include an electron injection layer containing Yb.

[0020] In an exemplary embodiment, a display device may include a circuit layer and a display element layer disposed on the circuit layer and including a light-emitting element and a pixel defining layer including a pixel aperture. The light-emitting element may include a first electrode, a light-emitting structure disposed on the first electrode and including an emission layer, a second electrode disposed on the light-emitting structure and including silver (Ag) and a metal dopant, and a capping layer disposed directly on the second electrode. The average volume ratio of the metal dopant in the second electrode may be less than or equal to about 30%, and the volume ratio of the metal dopant in the region adjacent to the capping layer is less than the average volume ratio of the metal dopant in the second electrode.

[0021] In an embodiment, the metal dopant may include at least one of Al, Au, Cu, Mg, Ti, In, Ni, C, Pd, F, Na, Si, Ca, Mn, Fe, Co, Zn, Ga, Ge, Mo, Sn, In, Pt, Pb, Fe, Yb, Lu, and Pa.

[0022] In an embodiment, the second electrode may include a first region, a second region, and a third region. The first region includes a first surface in contact with the capping layer, the second region includes a second surface in contact with the light-emitting structure, the third region is disposed between the first region and the second region, and a first volume ratio of the metal dopant in the first region and a second volume ratio of the metal dopant in the second region may both be less than the average volume ratio of the metal dopant in the second electrode.

[0023] In an embodiment, a third volume ratio of the metal dopant in the third region may be greater than the average volume ratio of the metal dopant in the second electrode.

[0024] In an embodiment, the third region may include: a first sub-region having a third volume ratio of the metal dopant that is less than the average volume ratio of the metal dopant in the second electrode; a second sub-region disposed between the first region and the first sub-region and having a fourth volume ratio of the metal dopant that is greater than the average volume ratio of the metal dopant in the second electrode; and a third sub-region disposed between the second region and the first sub-region and having a fifth volume ratio of the metal dopant that is greater than the average volume ratio of the metal dopant in the second electrode.

[0025] In an embodiment, the metal dopant may be Mg, and the second electrode may be formed by co-depositing silver and Mg using a thermal evaporation method.

[0026] In an embodiment, the light-emitting structure may include an emission layer, a hole transport region disposed between the first electrode and the emission layer, and an electron transport region disposed between the emission layer and the second electrode, and the electron transport region may be disposed directly below the second electrode and include an electron injection layer containing Yb. Description of the Drawings

[0027] The accompanying drawings are included to provide a further understanding of the disclosure, and the drawings are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the disclosure and, together with the description, are used to explain the principles of the disclosure. In the drawings: Figure 1 is a perspective view of a display device according to an embodiment; Figure 2 is a schematic cross-sectional view showing a part corresponding to Figure 1 line I-I'; Figure 3 is a plan view showing a display device of an embodiment; Figure 4 is a schematic cross-sectional view showing a part corresponding to Figure 3 line II-II'; Figure 5 is a schematic cross-sectional view showing a light-emitting element of an embodiment; Figure 6A is a schematic cross-sectional view magnifying a partial area of a light-emitting element of an embodiment; Figure 6B is a graph showing the doping concentration distribution of a metal dopant in a second electrode in a light-emitting element according to an embodiment; Figure 7A is a graph showing the doping concentration distribution of a metal dopant in a second electrode of an example; Figure 7B is a graph showing the doping concentration distribution of a metal dopant in a second electrode of a comparative example; Figure 7C is a graph showing the results of transmittance of an evaluation example and a comparative example; Figure 7D is a graph showing the results of reflectance of an evaluation example; Figure 8 is a schematic cross-sectional view magnifying a partial area of a light-emitting element of an embodiment; Figure 9A is a graph showing the doping concentration distribution of a metal dopant in a second electrode of an example; Figure 9B is a graph showing the results of transmittance of an evaluation example; Figure 10 is a schematic cross-sectional view magnifying a partial area of a light-emitting element of an embodiment; Figure 11A is a graph showing the doping concentration distribution of a metal dopant in a second electrode of an example; and Figure 11B is a graph showing the results of transmittance of an evaluation example. Detailed Description

[0028] The disclosure may be modified in many alternative forms, and specific embodiments will be shown in the drawings and described in detail. However, it should be understood that the disclosure is not intended to be limited to the specific forms disclosed, but is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure.

[0029] When an element or layer is referred to as being "on", "connected to", or "coupled to" another element or layer, the element or layer can be directly on, directly connected to, or directly coupled to the other element or layer, or there can be intervening elements or layers. However, when an element or layer is referred to as being "directly on", "directly connected to", or "directly coupled to" another element or layer, there are no intervening elements or layers. For this reason, the term "connected" can refer to physical connection, electrical connection, and / or fluid connection with or without intervening elements. In addition, when an element is referred to as being "in contact with" or "contacting" another element, etc., the element can be "electrically in contact with" or "physically in contact with" the other element; or "indirectly in contact with" or "directly in contact with" the other element.

[0030] Like reference numerals denote like elements. The use of cross-hatching and / or shading in the drawings is generally provided to clarify the boundaries between adjacent elements. Thus, unless stated, the presence or absence of cross-hatching or shading does not convey or indicate any preference or requirement for a particular material, material property, size, scale, commonality between the elements shown, and / or any other characteristic, attribute, property, etc. of the elements. In addition, in the drawings, the dimensions and relative dimensions of elements may be exaggerated for clarity and / or for descriptive purposes. When embodiments can be implemented differently, a particular process order can be performed in a different order than described. For example, two consecutively described processes can be performed substantially simultaneously or in an order opposite to the described order. In addition, like reference numerals and / or reference designations denote like elements.

[0031] In the specification and claims, for purposes of their meaning and interpretation, the phrase "at least one of..." is intended to include the meaning of "at least one of the group consisting of...". For example, "at least one of A and B" can be understood to mean "A, B, or A and B". In the specification and claims, for purposes of their meaning and interpretation, the term "and / or" is intended to include any combination of the terms "and" and "or". For example, "A and / or B" can be understood to mean "A, B, or A and B". The terms "and" and "or" can be used in a conjunctive sense or a disjunctive sense and can be understood to be equivalent to "and / or".

[0032] Taking into account the measurements discussed and the errors associated with the measurement of a particular quantity (i.e., the limitations of the measurement system), as used herein, "about" or "approximate" includes the stated value and means within an acceptable deviation of the particular value as determined by one of ordinary skill in the art. For example, "about" can mean within one or more standard deviations, or within ±30%, ±20%, ±10%, ±5% of the stated value.

[0033] 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 disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. Unless the context clearly dictates otherwise, the singular forms are also intended to include the plural forms.

[0034] For descriptive purposes, spatial relative terms such as "under", "below", "beneath", "lower", "above", "upper", "on top of", "higher", "side" (e.g., as in "sidewall") may be used herein to describe the relationship of one element to another (other) element as shown in the figures. Spatial relative terms are intended to encompass different orientations of the device in use, operation, and / or manufacture in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, an element described as "under" or "beneath" another element or feature will then be oriented "on top of" the other element or feature. Thus, the exemplary term "under" can include both an orientation of above and below. Additionally, the device may be otherwise oriented (e.g., rotated 90 degrees or at other orientations), and accordingly, the spatial relative descriptors used herein are to be interpreted accordingly.

[0035] It should be understood that the terms "comprising" or "having" are intended to specify the presence of the stated features, integers, steps, operations, elements, components, or combinations thereof in the disclosure, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

[0036] As used herein, "directly disposed on" can mean that there is no additional layer, film, region, plate, etc. between a component (such as a layer, film, region, plate, etc.) and another component. For example, "directly disposed on" can mean that two layers or two members are disposed without using an additional member such as an adhesive member therebetween.

[0037] 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. In addition, terms such as those defined in a general dictionary should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense unless clearly so defined herein.

[0038] Hereinafter, a light-emitting element and a display device according to an embodiment of the disclosure will be described with reference to the drawings.

[0039] Figure 1 is a perspective view showing a display device according to an embodiment. The display device DD may be a device activated according to an electrical signal. For example, the display device DD may be a large-sized device such as a television, a monitor, or an outdoor billboard. For example, the display device DD may be a medium- or small-sized device such as a personal computer, a laptop computer, a personal digital terminal, a car navigation system, a game machine, a smart phone, a tablet computer, and a camera. However, the disclosure is not limited thereto, and other electronic devices may be adopted as long as they do not depart from the disclosure.

[0040] The display device DD may display an image (or video) through a display surface DD-IS. The display surface DD-IS may be parallel to a plane defined by a first direction DR1 and a second direction DR2 intersecting the first direction DR1. The display surface DD-IS may include a display area DA and a non-display area NDA.

[0041] In the display area DA, pixels PX may be provided. The non-display area NDA may be a portion where no pixels PX are provided. The non-display area NDA may be defined along the edge of the display surface DD-IS. The non-display area NDA may surround the display area DA in a plan view. However, the disclosure is not limited thereto, and the non-display area NDA may not be provided, or the non-display area NDA may be provided only on one side of the display area DA.

[0042] Figure 1 A display device DD having a flat display surface DD-IS is shown, but the disclosure 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 facing different directions.

[0043] Figure 1The following drawings illustrate a first direction DR1 to a third direction DR3, and the directions indicated by the first to third directions DR1, DR2, and DR3 described herein are relative concepts and can thus be changed to other directions. Additionally, the directions indicated by the first to third directions DR1, DR2, and DR3 can be described as the first to third directions and the same reference numerals can be used. The first direction DR1 and the second direction DR2 can be perpendicular to each other, and the third direction DR3 can be the normal direction of the plane defined by the first direction DR1 and the second direction DR2. In the specification, the term "plane" refers to the plane defined by the first direction DR1 and the second direction DR2, and the term "section" refers to a plane perpendicular to the plane defined by the first direction DR1 and the second direction DR2 and parallel to the third direction DR3. The thickness direction of the display device DD can be parallel to the third direction DR3, which is the normal direction with respect to the plane defined by the first direction DR1 and the second direction DR2.

[0044] The upper surface (or front surface) and the lower surface (or rear surface) of the component constituting the display device DD can be defined relative to the third direction DR3. For example, among the two surfaces of a component facing the third direction DR3, the surface relatively adjacent to the display surface DD-IS can be defined as the front surface (or upper surface), and the surface relatively spaced apart from the display surface DD-IS can be defined as the rear surface (or lower surface). In the specification, the upper part (or upper side) and the lower part (or lower side) can be defined relative to the third direction DR3, and the upper part (or upper side) can be defined as the direction towards the display surface DD-IS, and the lower part (or lower side) can be defined as the direction away from the display surface DD-IS.

[0045] Here, when a component is "directly disposed / directly formed" on another component, it means that a third component is not disposed between the one component and the other component. For example, when a component is "directly placed / directly formed" on another component, it means that the component is "in contact" with the other component.

[0046] Figure 2 is a schematic cross-sectional view showing a part corresponding to Figure 1 the line I-I'. Figure 2 It can be a schematic cross-sectional view of a display device according to an embodiment.

[0047] The display device DD can include a display panel DP and an optical structure layer PP disposed on the display panel DP. The display panel DP can include a display element layer DP-EL. The display element layer DP-EL can include a light-emitting element ED ( Figure 4). In an embodiment, the display panel DP may further include a encapsulation layer TFE disposed on the display element layer DP-EL. The encapsulation layer TFE may be directly disposed on the display element layer DP-EL, or may be joined to the display element layer DP-EL through a separate member.

[0048] An optical structure layer PP may be disposed on the display panel DP to control reflected light caused by external light in the display panel DP. The optical structure layer PP may be a reflection reduction layer that reduces the reflectance of external light. For example, the optical structure layer PP may include a polarizing film including a phase retarder and / or a polarizer, a multilayer reflection layer that causes destructive interference of the reflected light, or a color filter disposed corresponding to the pixel arrangement and emission color of the display panel DP. In the case where the optical structure layer PP includes a color filter, the color filter may be arranged in consideration of the emission color of the pixels included in the display panel DP. In another embodiment, the optical structure layer PP may not be provided.

[0049] The display panel DP may be configured to substantially generate an image. In the display device DD of the embodiment, the display panel DP may be a light-emitting display panel. In the display device DD according to the embodiment, the display element layer DP-EL may be a self-emitting display layer. For example, the display element layer DP-EL may include a micro LED display layer, a nano LED display layer, an organic light-emitting display layer, or a quantum dot light-emitting display layer. However, the disclosure is not limited thereto, as long as the display element implements a self-emitting display element layer.

[0050] The organic light-emitting display layer may include an organic electroluminescent element including an organic light-emitting material. The quantum dot light-emitting display layer may include an emission layer including quantum dots and / or quantum rods. The micro LED display layer may include micro light-emitting diode elements as ultra-small light-emitting elements, and the nano LED display layer may include nano light-emitting diode elements. Hereinafter, the display element layer DP-EL is described as an organic light-emitting display layer according to an embodiment. However, for components other than the emission layer, these components may be applied to the structures of other display layers other than the organic light-emitting display layer.

[0051] The display panel DP may include a substrate base BS, a circuit layer DP-CL disposed on the substrate base BS, and a display element layer DP-EL disposed on the circuit layer DP-CL.

[0052] Figure 3 is a plan view of a display device according to an embodiment. Figure 4 is a schematic cross-sectional view showing a portion corresponding to line II-II' of Figure 3 Figure 4 may be a schematic cross-sectional view showing a display device of an embodiment.

[0053] Refer to​Figure 3 and Figure 4 ,the display device DD may include a plurality of light-emitting regions PXA-B, PXA-G, and PXA-R that are repeatedly arranged throughout the display area DA ( Figure 1 ). The display device DD of the embodiment may include first to third light-emitting regions PXA-B, PXA-G, and PXA-R that are different from each other. In an embodiment, the display device DD may include a peripheral region NPXA disposed around the first to third light-emitting regions PXA-B, PXA-G, and PXA-R. The peripheral region NPXA may define the boundaries between the first to third light-emitting regions PXA-B, PXA-G, and PXA-B. The peripheral region NPXA may surround the first to third light-emitting regions PXA-B, PXA-G, and PXA-B in a plan view. A structure (e.g., a pixel defining layer PDL) for preventing color mixing between the first to third light-emitting regions PXA-B, PXA-G, and PXA-R may be provided in the peripheral region NPXA.

[0054] The pixel defining layer PDL may define the light-emitting regions PXA-B, PXA-G, and PXA-R. The light-emitting regions PXA-B, PXA-G, and PXA-R and the peripheral region NPXA may be separated by the pixel defining layer PDL.

[0055] The display panel DP according to an embodiment may include a plurality of light-emitting elements ED-1, ED-2, and ED-3 that emit light in different wavelength ranges. The light-emitting elements ED-1, ED-2, and ED-3 may emit light of different colors. For example, the display panel DP may include a first light-emitting element ED-1 that emits blue light, a second light-emitting element ED-2 that emits green light, and a third light-emitting element ED-3 that emits red light. However, the disclosure is not limited thereto, and in another embodiment, the first to third light-emitting elements ED-1, ED-2, and ED-3 may emit light in the same wavelength range, or at least one of the first to third light-emitting elements ED-1, ED-2, and ED-3 may emit light in different wavelength ranges.

[0056] The light-emitting regions PXA-B, PXA-G, and PXA-R may each be a region that emits light generated from each of the light-emitting elements ED-1, ED-2, and ED-3. Figure 3 and Figure 4 The first to third light-emitting regions PXA-B, PXA-G, and PXA-R that respectively emit blue light, green light, and red light are shown. For example, the display device DD of the embodiment may include a separate first light-emitting region PXA-B that emits blue light, a second light-emitting region PXA-G that emits green light, and a third light-emitting region PXA-R that emits red light.

[0057] In Figure 3 and Figure 4 In the display device DD of the embodiment shown, the light-emitting regions PXA-B, PXA-G, and PXA-R may have areas of different sizes according to the colors of light emitted from the emission layers EML-B, EML-G, and EML-R of the light-emitting elements ED-1, ED-2, and ED-3. Figure 3 As an example, the first to third light-emitting regions PXA-B, PXA-G, and PXA-R having the same planar shape and different planar areas in a plan view are shown, but the disclosure is not limited thereto.

[0058] The first light-emitting region PXA-B corresponding to the first light-emitting element ED-1 that emits blue light may have the largest area, and the second light-emitting region PXA-G corresponding to the second light-emitting element ED-2 that emits green light may have the smallest area. However, the disclosure is not limited thereto, and the first to third light-emitting regions PXA-B, PXA-G, and PXA-R may emit light of colors other than blue, green, and red. In another embodiment, the first to third light-emitting regions PXA-B, PXA-G, and PXA-R may have the same area, or may be set in an area ratio different from that of the Figure 3 embodiment shown. The areas of the first to third light-emitting regions PXA-B, PXA-G, and PXA-R may be set according to the colors of the emitted light. The area may be the area in a plan view.

[0059] The first light-emitting region PXA-B and the third light-emitting region PXA-R may be alternately arranged in a first direction DR1 to form a first group PXG1. The second light-emitting region PXA-G may be arranged in the first direction DR1 to form a second group PXG2. The first group PXG1 may be spaced apart from the second group PXG2 in a second direction DR2. Both the first group PXG1 and the second group PXG2 may be provided in a plurality. The first group PXG1 and the second group PXG2 may be alternately arranged in the second direction DR2.

[0060] One third light-emitting region PXA-R may be spaced apart from one second light-emitting region PXA-G in a fourth direction DR4. One first light-emitting region PXA-B may be spaced apart from one second light-emitting region PXA-G in a fifth direction DR5. The fourth direction DR4 may be a direction between the first direction DR1 and the second direction DR2. The fifth direction DR5 may intersect the fourth direction DR4 and may be inclined with respect to the second direction DR2.

[0061] The arrangement structure of the light-emitting regions PXA-B, PXA-G, and PXA-R is not limited to Figure 3The arrangement structure shown in the figure. For example, in the light-emitting regions PXA-B, PXA-G, and PXA-R, the first light-emitting region PXA-B, the second light-emitting region PXA-G, and the third light-emitting region PXA-R may be arranged sequentially and alternately in the first direction DR1. The shapes of the light-emitting regions PXA-B, PXA-G, and PXA-R in the plan view are not limited to Figure 3 the embodiments shown in the figure, and the light-emitting regions PXA-B, PXA-G, and PXA-R may have different shapes.

[0062] Referring to Figure 4 , the display device DD may include a display panel DP and an optical structure layer PP stacked in the third direction DR3. The display panel DP may include a substrate base BS, a circuit layer DP-CL provided on the substrate base BS, a display element layer DP-EL provided on the circuit layer DP-CL, and a packaging layer TFE provided on the circuit layer DP-CL. The display element layer DP-EL may include a pixel defining layer PDL and a light-emitting element ED provided between the pixel defining layers PDL or on the pixel defining layer PDL.

[0063] The substrate base BS may be a member that provides a substrate surface on which the display element layer DP-EL is provided. The substrate base BS may be a glass substrate, a metal substrate, a plastic substrate, etc. However, the disclosure is not limited thereto, and the substrate base BS may be an inorganic layer, an organic layer, or a composite material layer.

[0064] The substrate base BS may include a single-layer structure or a multi-layer structure. For example, the substrate base BS may include a first synthetic resin layer, a multi-layer or single-layer intermediate layer, and a second synthetic resin layer stacked in sequence. The intermediate layer may be referred to as a substrate barrier layer. The intermediate layer may include a silicon oxide (SiO x ) layer and an amorphous silicon (a-Si) layer provided on the silicon oxide layer, but the disclosure is not particularly limited thereto. For example, the intermediate layer may include at least one of a silicon oxide layer, a silicon nitride layer, a silicon oxynitride layer, and an amorphous silicon layer. The substrate base BS may be a flexible substrate that can be easily bent or folded.

[0065] Both the first synthetic resin layer and the second synthetic resin layer may include polyimide-based resins. In an embodiment, both the first synthetic resin layer and the second synthetic resin layer may include at least one of acrylate-based resins, methacrylate-based resins, polyisoprene-based resins, vinyl-based resins, epoxy-based resins, urethane-based resins, cellulose-based resins, silicone-based resins, polyamide-based resins, and perylene-based resins. As used herein, "~~-based" resins may be considered to include the functional groups of "~~".

[0066] In an embodiment, the circuit layer DP-CL may be disposed on the substrate base BS, and the circuit layer DP-CL may include a plurality of transistors (not shown). The transistors (not shown) may each 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 for driving the light-emitting element ED of the display element layer DP-EL.

[0067] The display element layer DP-EL may be disposed on the circuit layer DP-CL. The display element layer DP-EL may include a pixel defining layer PDL and first to third light-emitting elements ED-1, ED-2, and ED-3 divided by the pixel defining layer PDL. The light-emitting elements ED-1, ED-2, and ED-3 of the display element layer DP-EL may be electrically connected to the driving elements of the circuit layer DP-CL, and may thus generate light according to the signals provided by the driving elements to display an image.

[0068] The first to third light-emitting elements ED-1, ED-2, and ED-3 may emit light in different wavelength ranges. In another embodiment, the first to third light-emitting elements ED-1, ED-2, and ED-3 may emit light in the same wavelength range, or one light-emitting element may emit light in a wavelength range different from that of the other light-emitting elements.

[0069] The pixel defining layer PDL may be formed of a polymer resin. For example, the pixel defining layer PDL may include a polyacrylate resin or a polyimide resin. In an embodiment, in addition to the polymer resin, the pixel defining layer PDL may further include an inorganic material. In an embodiment, the pixel defining layer PDL may include a light absorption material, or a black pigment or a black dye. The pixel defining layer PDL including a black pigment or a black dye may achieve a black pixel defining layer. When forming the pixel defining layer PDL, carbon black may be used as the black pigment or black dye, but the disclosure is not limited thereto.

[0070] In an embodiment, the pixel defining layer PDL may be formed of an inorganic material. For example, the pixel defining layer PDL may be formed of at least one of silicon nitride (SiN x ), silicon oxide (SiO x ), silicon oxynitride (SiO x N y ), etc.

[0071] The pixel defining layer PDL may have a pixel opening OH. In a plan view, a part of the first electrode EL1 may be exposed through the pixel opening OH. The part corresponding to the first electrode EL1 exposed by the pixel opening OH may be defined as a light-emitting region PXA-B, PXA-G, and PXA-R. However, the disclosure is not limited thereto.

[0072] The pixel defining layer PDL can separate the first to third light emitting elements ED-1, ED-2, and ED-3. The emission layers EML-B, EML-G, and EML-R of the light emitting elements ED-1, ED-2, and ED-3 can be disposed and separated in the pixel opening OH defined by the pixel defining layer PDL.

[0073] The first to third light emitting elements ED-1, ED-2, and ED-3 may each include a first electrode EL1, a second electrode EL2 facing the first electrode EL1, emission layers EML-B, EML-G, and EML-R disposed between the first electrode EL1 and the second electrode EL2, a functional layer FL disposed between the first electrode EL1 and the second electrode EL2, and a cover layer CPL disposed on the second electrode EL2. The functional layer FL may be disposed at least at one position between the first electrode EL1 and the emission layers EML-B, EML-G, and EML-R and between the emission layers EML-B, EML-G, and EML-R and the second electrode EL2. In an embodiment, the first to third light emitting elements ED-1, ED-2, and ED-3 may each include a first electrode EL1, a first functional layer FL-B, emission layers EML-B, EML-G, and EML-R, a second functional layer FL-T, a second electrode EL2, and a cover layer CPL stacked in sequence in the third direction DR3. The cover layer CPL may be directly disposed on the second electrode EL2.

[0074] The first electrode EL1 may be exposed through the pixel opening OH of the pixel defining layer PDL. The first electrode EL1 may have conductivity. The first electrode EL1 may be formed of a metal material, a metal alloy, or a conductive compound. The first electrode EL1 may be an anode or a cathode. In an embodiment, the first electrode EL1 may be a pixel electrode. However, the disclosure is not limited thereto.

[0075] The second electrode EL2 may be disposed on the first electrode EL1. The second electrode EL2 may be a cathode or an anode. In an embodiment, when the first electrode EL1 is an anode, the second electrode EL2 may be a cathode, and when the first electrode EL1 is a cathode, the second electrode EL2 may be an anode. The second electrode EL2 may be a common electrode. However, the disclosure is not limited thereto.

[0076] One of the first functional layer FL-B disposed between the first electrode EL1 and the emission layers EML-B, EML-G, and EML-R and the second functional layer FL-T disposed between the emission layers EML-B, EML-G, and EML-R and the second electrode EL2 may be a hole transport region, and the other may be an electron transport region. Refer to Figure 4, the first functional layer FL-B and the second functional layer FL-T may be provided as a common layer throughout the light-emitting regions PXA-B, PXA-G, and PXA-R. In an embodiment, the functional layer FL may be stacked with both the emission layers EML-B, EML-G, and EML-R and the pixel definition layer PDL in a third direction DR3. However, the disclosure is not limited thereto, and at least one of the first functional layer FL-B and the second functional layer FL-T may be stacked with the emission layers EML-B, EML-G, and EML-R in the third direction DR3, and may be patterned and provided in the pixel opening OH.

[0077] The encapsulation layer TFE may be provided on the display element layer DP-EL. The encapsulation layer TFE may include an organic material or an inorganic material. The encapsulation layer TFE may have a multi-layer structure in which an inorganic layer and an organic layer are repeated. In an embodiment, the encapsulation layer TFE may include a first inorganic layer IOL1, an organic layer OL, and a second inorganic layer IOL2 that are sequentially stacked. However, the layers constituting the encapsulation layer TFE are not limited thereto. The encapsulation layer TFE may be directly provided on the light-emitting element ED by a roll-to-roll process. In an embodiment, the encapsulation layer TFE may be directly provided on the cover layer CPL.

[0078] The first inorganic layer IOL1 and the second inorganic layer IOL2 may protect the light-emitting element ED from moisture and oxygen, and the organic layer OL may protect the light-emitting element ED from foreign substances such as dust particles. For example, the organic layer OL may prevent a depression defect on the light-emitting element ED caused by foreign substances introduced during the manufacturing process. Although not shown, the display device DD may further include a refractive index control layer provided on the upper side of the encapsulation layer TFE to increase the light output efficiency.

[0079] The first inorganic layer IOL1 and the second inorganic layer IOL2 may include at least one of silicon nitride, silicon oxynitride, silicon oxide, titanium oxide, and aluminum oxide. The organic layer OL may include an acryloyl-based organic material. However, the types of materials constituting the inorganic layers IOL1 and IOL2 and the organic layer OL are not limited thereto.

[0080] Referring to Figure 4 , the display device DD of the embodiment may include an optical structure layer PP provided on the display panel DP. The optical structure layer PP may include a substrate layer BL and a color filter layer CFL.

[0081] The substrate layer BL may be a member that provides a substrate surface on which the color filter layer CFL is provided. The substrate layer BL may be a glass substrate, a metal substrate, a plastic substrate, etc. However, the disclosure is not limited thereto, and the substrate layer BL may be an inorganic layer, an organic layer, or a composite material layer.

[0082] The color filter layer CFL may include color filters CF-B, CF-G, and CF-R. The color filter layer CFL may include a first color filter to a third color filter CF-B, CF-G, and CF-R. The first color filter to the third color filter CF-B, CF-G, and CF-R may each be arranged to correspond to the first light-emitting element to the third light-emitting element ED-1, ED-2, and ED-3. For example, the first color filter CF-B may be a blue color filter, the second color filter CF-G may be a green color filter, and the third color filter CF-R may be a red color filter. The first color filter to the third color filter CF-B, CF-G, and CF-R may each be arranged to correspond to a respective light-emitting region among the first light-emitting region to the third light-emitting region PXA-B, PXA-G, and PXA-R.

[0083] In an embodiment, the color filters CF-B, CF-G, and CF-R that transmit different lights may be stacked with the peripheral region NPXA provided between the light-emitting regions PXA-B, PXA-G, and PXA-R. The color filters CF-B, CF-G, and CF-R may be stacked on each other in a third direction DR3 that is a thickness direction to separate the boundaries between adjacent light-emitting regions PXA-B, PXA-G, and PXA-R. Accordingly, the effect of blocking external light may be increased, and the color filters CF-B, CF-G, and CF-R may be used as a black matrix. The stacked structure of the color filters CF-B, CF-G, and CF-R may be used to prevent color mixing.

[0084] The first color filter to the third color filter CF-B, CF-G, and CF-R may each include a polymer photosensitive resin and a pigment or a dye. The first color filter CF-B may include a blue pigment or a blue dye, the second color filter CF-G may include a green pigment or a green dye, and the third color filter CF-R may include a red pigment or a red dye. However, the disclosure is not limited thereto, and the first color filter CF-B may not include a pigment or a dye. The first color filter CF-B may include a polymer photosensitive resin but not include a pigment or a dye. The first color filter CF-B may be transparent. The first color filter CF-B may be formed of a transparent photosensitive resin.

[0085] The color filter layer CFL may further include a buffer layer BFL. For example, the buffer layer BFL may be a protective layer that protects the first color filter to the third color filter CF-B, CF-G, and CF-R. The buffer layer BFL may be an inorganic material layer including at least one of silicon nitride, silicon oxide, and silicon oxynitride. The buffer layer BFL may be formed of a single layer or multiple layers.

[0086] In an embodiment, the second color filter CF-G and the third color filter CF-R may be yellow color filters. The second color filter CF-G and the third color filter CF-R may not be separated from each other and may be provided as a single unit.

[0087] Although not shown, the color filter layer CFL may further include a light blocking unit (not shown). The light blocking unit may be a black matrix. The light blocking unit may include an organic light blocking material or an inorganic light blocking material, both including a black pigment or a black dye. The light blocking unit may prevent light leakage and separate the boundaries between adjacent color filters CF-B, CF-G, and CF-R. The light blocking unit (not shown) may be stacked with the pixel defining layer PDL in the third direction DR3 and correspond to the peripheral area NPXA. In another embodiment, different from what is shown in Figure 4 etc., the optical structure layer PP of the display device DD may not include the color filter layer CFL.

[0088] Figure 5 is a schematic cross-sectional view showing a light-emitting element according to an embodiment. Referring to Figure 5 The structure of the light-emitting element ED described can be applied to Figure 4 at least one of the first to third light-emitting elements ED-1, ED-2, and ED-3 shown in Figure 5 In

[0089] In Figure 5 etc., in the light-emitting element ED according to the disclosed embodiment, one light-emitting structure EU is shown to be disposed between the first electrode EL1 and the second electrode EL2, but the disclosure is not limited thereto. For example, in another embodiment, a plurality of light-emitting structures may be disposed between the first electrode EL1 and the second electrode EL2, each light-emitting structure EU may include an emission layer EML, and a charge generation layer (not shown) may be disposed between the light-emitting structures EU. The charge generation layer (not shown) may generate charges (electrons and holes) and supply the charges to each of the adjacent light-emitting structures EU.

[0090] In Figure 5 In the embodiment shown in Figure 4 in the first to third light-emitting elements ED-1, ED-2, and ED-3 shown in

[0091] In Figure 5In the light-emitting element ED shown, the first electrode EL1 may be an anode, and the second electrode EL2 may be a cathode. In an embodiment, the first electrode EL1 may be a reflective electrode, and the second electrode EL2 may be a transmissive electrode or a transmissive-reflective electrode. The light-emitting element ED of the embodiment may have a top-emission light-emitting structure in which light is emitted above the second electrode EL2.

[0092] In an embodiment, the first electrode EL1 may be a reflective electrode. The first electrode EL1 may include at least one of Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF, Mo, Ti, W, their compounds, their mixtures, and their oxides.

[0093] The first electrode EL1 may include a transparent metal oxide, such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), and indium tin zinc oxide (ITZO). In an embodiment, the first electrode EL1 may include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF, Mo, Ti, W, their compounds, or their mixtures (e.g., a mixture of Ag and Mg), or a material having a multilayer structure such as LiF / Ca (a stacked structure of LiF and Ca) or LiF / Al (a stacked structure of LiF and Al). In another embodiment, the first electrode EL1 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), indium tin zinc oxide (ITZO), etc. For example, the first electrode EL1 may have a three-layer structure of ITO / Ag / ITO, but the disclosure is not limited thereto. In an embodiment, the first electrode EL1 may include the above metal materials, combinations of the above metal materials, or oxides of the above metal materials, but the disclosure is not limited thereto. The first electrode EL1 may have a thickness in the range of about 700 Å to about 10,000 Å. For example, the first electrode EL1 may have a thickness in the range of 1000 Å to about 3000 Å.

[0094] The hole transport region can be provided as a first functional layer FL-B on the first electrode EL1 (hereinafter, referred to as the hole transport region). In the light-emitting element ED according to the embodiment, the hole transport region FL-B may include at least one of a hole injection layer HIL and a hole transport layer HTL. The hole transport region FL-B may have a single-layer structure formed of one material, a single-layer structure formed of different materials, or a multilayer structure having multiple layers formed of different materials. The hole injection layer HIL and the hole transport layer HTL may each have a single-layer structure or a multilayer structure. The hole transport region FL-B may further include components such as an electron blocking layer and a buffer layer in addition to the hole injection layer HIL and the hole transport layer HTL.

[0095] The hole transport region FL-B can be formed by methods such as a vacuum deposition method, a spin coating method, a casting method, a Langmuir-Blodgett (LB) method, an inkjet printing method, a laser printing method, and a laser-induced thermal imaging (LITI) method.

[0096] The hole transport region FL-B may include a hole injection material and / or a hole transport material. For example, the hole transport region FL-B may include a phthalocyanine compound (such as copper phthalocyanine), N 1 ,N 1 '-([1,1'-biphenyl]-4,4'-diyl)bis(N 1 -phenyl-N 4 ,N 4 -di-m-tolylbenzene-1,4-diamine) (DNTPD), 4,4',4''-[tris(3-methylphenyl)phenylamino]triphenylamine (m-MTDATA), 4,4',4''-tris(N,N-diphenylamino)triphenylamine (TDATA), 4,4',4''-tris[N-(2-naphthyl)-N-phenylamino]triphenylamine (2-TNATA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), polyaniline / camphorsulfonic acid (PANI / CSA), polyaniline / poly(4-styrenesulfonate) (PANI / PSS), N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine (NPB), a triphenylamine-containing polyether ketone (TPAPEK), 4-isopropyl-4'-methyldiphenyliodonium [tetrakis(pentafluorophenyl)borate], dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN), etc.

[0097] In an embodiment, the hole transport region FL-B may include at least one of carbazole derivatives (such as N-phenylcarbazole or polyvinylcarbazole), fluorene derivatives, N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD), triphenylamine derivatives (such as 4,4',4''-tris(N-carbazolyl)triphenylamine (TCTA)), N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine (NPB), 4,4'-cyclohexylidene-bis[N,N-bis(4-methylphenyl)aniline] (TAPC), 4,4'-bis[N,N'-(3-tolyl)amino]-3,3'-dimethylbiphenyl (HMTPD), 9-(4-tert-butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole (CzSi), 9-phenyl-9H-3,9'-bicarbazole (CCP), 1,3-bis(N-carbazolyl)benzene (mCP), 1,3-bis(1,8-dimethyl-9H-carbazol-9-yl)benzene (mDCP), etc.

[0098] The hole transport region FL-B may have a thickness in the range of about 5 nm to about 1,500 nm. For example, the hole transport region FL-B may have a thickness in the range of about 10 nm to about 500 nm. When the thickness of the hole transport region FL-B satisfies the above range, satisfactory hole transport properties can be obtained without significantly increasing the driving voltage.

[0099] In the light-emitting element ED of the embodiment, the emission layer EML may be disposed on the hole transport region FL-B. In the light-emitting element ED according to the embodiment, the emission layer EML may include anthracene derivatives, pyrene derivatives, fluoranthene derivatives, chrysene derivatives, dihydrobenzanthracene derivatives, or benzophenanthrene derivatives. For example, the emission layer EML may include anthracene derivatives or pyrene derivatives.

[0100] 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(carbazol-9-yl)benzene (mCP), 2,8-bis(diphenylphosphoryl)dibenzofuran (PPF), 4,4',4''-tris(carbazol-9-yl)triphenylamine (TCTA), and 1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene (TPBi) as host materials. However, the disclosure is not limited thereto. In another embodiment, tris(8-hydroxyquinoline)aluminum (Alq3), 9,10-di(naphthalen-2-yl)anthracene (ADN), 2-tert-butyl-9,10-di(naphthalen-2-yl)anthracene (TBADN), stilbenylarylide (DSA), 4,4'-bis(carbazol-9-yl)-2,2'-dimethyl-biphenyl (CDBP), 2-methyl-9,10-di(naphthalen-2-yl)anthracene (MADN), hexaphenylcyclotriphosphazene (CP1), 1,4-bis(triphenylsilyl)benzene (UGH2), hexaphenylcyclotrisiloxane (DPSiO3), octaphenylcyclotetrasiloxane (DPSiO4), etc. may be used as host materials.

[0101] The emission layer EML may include at least one of 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 or perylene derivatives (e.g., 2,5,8,11-tetra-tert-butylperylene (TBP)), pyrene or pyrene derivatives (e.g., 1,1'-dipyrene, 1,4-dipyrenylbenzene, 1,4-bis(N,N-diphenylamino)pyrene), etc. as dopant materials.

[0102] The emission layer EML may also include a phosphorescent dopant material. For example, metal complexes containing iridium (Ir), platinum (Pt), osmium (Os), gold (Au), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), or thulium (Tm) can be used as phosphorescent dopants. For example, bis(4,6-difluorophenylpyridine-N,C2')iridium(III) picolinate (FIrpic), bis(2,4-difluorophenylpyridine)-tetrakis(1-pyrazolyl)borate iridium(III) (FIr6), platinum octaethylporphyrin (PtOEP), etc. can be used as phosphorescent dopants. However, the disclosure is not limited thereto.

[0103] In an embodiment, the emission layer EML may include quantum dots as a light-emitting material.

[0104] In Figure 5 the embodiment shown, the emission layer EML may include a main emission layer EL_M and an auxiliary emission layer EL_S. The main emission layer EL_M and the auxiliary emission layer EL_S may include different materials.

[0105] In an embodiment, the main emission layer EL_M may include a host and a dopant material to emit light within a specific wavelength range. In an embodiment, the auxiliary emission layer EL_S may include a material for compensating the resonance distance and adjusting the hole charge balance according to the wavelength of the light emitted from the emission layer EML to increase the light-emitting efficiency. Figure 4 The emission layers EML-B, EML-G, and EML-R of the first light-emitting element to the third light-emitting element ED-1, ED-2, and ED-3 of the display element layer DP-EL shown in

[0106] In an embodiment, the presence or absence of the auxiliary emission layer EL_S and the thickness of the auxiliary emission layer EL_S may be adjusted according to the emission wavelength range of the main emission layer EL_M. For example, in Figure 4 the structure of the display element layer DP-EL according to an embodiment shown, the first emission layer EML-B of the first light-emitting element ED-1 that emits blue light may not include the auxiliary emission layer EL_S, and the second emission layer EML-G of the second light-emitting element ED-2 that emits green light and the third emission layer EML-R of the third light-emitting element ED-3 that emits red light may both include the auxiliary emission layer EL_S. In an embodiment, the auxiliary emission layer EL_S included in the third light-emitting element ED-3 may be thicker in the third direction DR3 than the auxiliary emission layer EL_S included in the second light-emitting element ED-2.

[0107] In Figure 5In [the figure], the thickness of the main emission layer EL_M and the thickness of the auxiliary emission layer EL_S are shown to be similar, but the disclosure is not limited thereto, and in another embodiment, the auxiliary emission layer EL_S may be thicker than the main emission layer EL_M.

[0108] In the light-emitting element ED of the embodiment, the electron transport region may be provided as a second functional layer FL-T (hereinafter referred to as the electron transport region) on the emission layer EML. The electron transport region FL-T may include at least one of an electron transport layer ETL and an electron injection layer EIL, but the disclosure is not limited thereto.

[0109] The electron transport region FL-T may have a single-layer structure formed of one material, a single-layer structure formed of different materials, or a multi-layer structure having multiple layers formed of different materials. For example, the electron transport region FL-T may have a single-layer structure of an electron injection layer EIL or an electron transport layer ETL, or may have a single-layer structure formed of an electron injection material and an electron transport material. The electron injection layer EIL and the electron transport layer ETL may each have a single-layer structure or a multi-layer structure. In addition to the electron injection layer EIL and the electron transport layer ETL, the electron transport region FL-T may further include components such as a hole blocking layer and a buffer layer. The electron transport region FL-T may have a thickness in the range of, for example, about 20 nm to about 150 nm.

[0110] The electron transport region FL-T may be formed by methods such as a vacuum deposition method, a spin coating method, a casting method, a Langmuir-Blodgett (LB) method, an inkjet printing method, a laser printing method, and a laser-induced thermal imaging (LITI) method.

[0111] The electron transport region FL-T may include an electron injection material and / or an electron transport material. For example, the electron transport region FL-T may include anthracene compounds. In another embodiment, the electron transport region FL-T may include, for example, tris(8-hydroxyquinoline)aluminum (Alq3), 1,3,5-tris[(3-pyridinyl)-benzene-3-yl]benzene, 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzimidazol-1-yl)phenyl)-9,10-dinaphthylanthracene, 1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene (TPBi), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), 3-(4-biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole ( tBis(2-methyl-8-hydroxyquinoline-N1,O8)-(4-hydroxy-1,1'-biphenyl)aluminum (BAlq), bis(benzoquinolin-10-olato)beryllium (Bebq2), 9,10-bis(naphthalen-2-yl)anthracene (ADN), 1,3-bis[3,5-bis(pyridin-3-yl)phenyl]benzene (BmPyPhB), or a mixture thereof. In another embodiment, the electron transport region FL-T may include 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), diphenyl(4-(triphenylsilyl)phenyl)phosphine oxide (TSPO1), 4,7-diphenyl-1,10-phenanthroline (Bphen), and the like.

[0112] In an embodiment, the electron transport region FL-T may include a metal halide (such as LiF, NaCl, CsF, RbCl, RbI, CuI, and KI), a lanthanide metal (such as Yb), or a co-deposited material of a metal halide and a lanthanide metal. For example, the electron transport region FL-T may include KI:Yb, RbI:Yb, LiF:Yb, etc. as co-deposited materials. In an embodiment, for the electron transport region FL-T, metal oxides (such as Li2O and BaO) or lithium 8-hydroxyquinolate (Liq) may be used, but the disclosure is not limited thereto. In an embodiment, the electron transport region FL-T may be formed of a mixture of an electron transport material and an insulating organometallic salt. The organometallic salt may be a material having a band gap greater than or equal to about 4 eV. For example, the organometallic salt may include, for example, metal acetates, metal benzoates, metal acetoacetates, metal acetylacetonates, or metal stearates.

[0113] The second electrode EL2 may be disposed on the electron transport region FL-T. In an embodiment, the second electrode EL2 may be directly disposed on the electron transport region FL-T. In an embodiment, the second electrode EL2 may be directly disposed on an electron injection layer EIL including KI:Yb, RbI:Yb, LiF:Yb, etc.

[0114] The second electrode EL2 may be a transmissive electrode or a transmissive-reflective electrode. The second electrode EL2 may include a metal host and a metal dopant. The second electrode EL2 may be formed by mixing two or more types of metals (such as a metal host and a metal dopant).

[0115] In an embodiment, the metal body of the second electrode EL2 may be silver (Ag). The second electrode EL2 may include Ag and a metal dopant. In an embodiment, the metal dopant of the second electrode EL2 may include at least one of Al, Au, Cu, Mg, Ti, In, Ni, C, Pd, F, Na, Si, Ca, Mn, Fe, Co, Zn, Ga, Ge, Mo, Sn, In, Pt, Pb, Fe, Yb, Lu, and Pa. For example, the metal dopant of the second electrode EL2 may be Mg, Al, Cu, Ca, or Ba. For example, the second electrode EL2 may include Ag and Mg as the metal dopant.

[0116] The second electrode EL2 may be formed using a thermal evaporation method. The second electrode EL2 may be formed by co-deposition of the metal body and the metal dopant. The metal dopant may improve the performance of the metal body as the main electrode material during film formation by thermal evaporation. For example, when forming the second electrode EL2 by co-depositing Ag as the metal body and Mg as the metal dopant through thermal evaporation, the metal dopant Mg may prevent the aggregation of Ag to form Ag islands. Therefore, in the case of co-depositing the metal dopant with Ag, the second electrode EL2 with excellent film uniformity and stability can be formed even using thermal evaporation.

[0117] The second electrode EL2 may have a thickness in the range of about 50 Å to about 300 Å. In the case of forming the second electrode EL2 using thermal evaporation, the second electrode EL2 may be provided with uniform film characteristics at a thickness in the range of about 50 Å to about 300 Å.

[0118] The capping layer CPL may be disposed on the second electrode EL2 of the light-emitting element ED. The capping layer CPL may include multiple layers or a single layer. The capping layer CPL may be directly disposed on the second electrode EL2.

[0119] In an embodiment, the capping layer CPL may be an organic layer or an inorganic layer. For example, in the case where the capping layer CPL includes an inorganic material, the inorganic material may include alkali metal compounds (such as LiF), alkaline earth metal compounds (such as MgF2), SiON, SiN x , SiO y , etc.

[0120] For example, in the case where the capping layer CPL includes an organic material, the organic material may include α-NPD, NPB, TPD, m-MTDATA, Alq3, CuPc, N4,N4,N4',N4'-tetrakis(biphenyl-4-yl)biphenyl-4,4'-diamine (TPD15), 4,4',4''-tris(carbazol-9-yl)triphenylamine (TCTA), etc., or may include an epoxy resin or an acrylate such as a methacrylate. However, the disclosure is not limited thereto, and in another embodiment, the capping layer CPL may include the following compounds P1 to P5.

[0121]

[0122] In an embodiment, the capping layer CPL may have a refractive index greater than or equal to about 1.6. For example, the capping layer CPL may have a refractive index greater than or equal to about 1.6 at a wavelength in the range of about 550 nm to about 660 nm.

[0123] In the case where the second electrode EL2 is formed by co-deposition of a metal host and a metal dopant, the deposition rates of the metal host and the metal dopant may be different. The ratio of the metal host and the metal dopant in the second electrode EL2 can be adjusted by changing the deposition rates of the metal host and the metal dopant. In an embodiment, the ratio of the metal dopant in the second electrode EL2 may vary depending on the position.

[0124] Figure 6A is a schematic cross-sectional view of a part of the light-emitting element of the enlarged embodiment. Figure 6A schematically shows Figure 5 the enlarged region XX'. Figure 6B is a diagram showing Figure 6A the doping concentration of the metal dopant along the thickness direction in the embodiment shown in.

[0125] Referring to Figure 6A , the second electrode EL2 may include a metal host HSM and a metal dopant DMT. The metal dopant DMT may be distributed throughout the second electrode EL2. The metal host HSM may be Ag. For example, the entire second electrode EL2 may be a layer formed by co-deposition of Ag and the metal dopant DMT.

[0126] Referring to Figure 6A and Figure 6B , in an embodiment, the ratio of the metal dopant DMT may be from the light-emitting structure EU ( Figure 5)(It) gradually decreases in the direction towards the cover layer CPL. In an embodiment, the ratio of the metal dopant DMT or the concentration of the metal dopant DMT may correspond to a volume ratio. The volume ratio of the metal dopant DMT in each region of the second electrode EL2 may correspond to the volume ratio of the metal dopant DMT in each region with respect to the total volume (100) of the second electrode EL2. The average volume ratio of the metal dopant DMT in the second electrode EL2 may correspond to the ratio of the metal dopant DMT with respect to the total volume (100) of the second electrode EL2.

[0127] Referring to Figure 6A and Figure 6B , the volume ratio of the metal dopant DMT in the first region ELR-T of the second electrode EL2 adjacent to the first surface US_EL2 in contact with the cover layer CPL may be less than the average volume ratio of the metal dopant DMT in the second electrode EL2.

[0128] In an embodiment, the ratio of the metal dopant DMT in the region adjacent to the cover layer CPL may be less than the ratio of the metal dopant DMT in other regions of the second electrode EL2, so that the diffusion of the metal dopant DMT having a work function smaller than that of the metal host HSM and a relatively small atomic diameter into the adjacent layer or the interface with the adjacent layer can be minimized.

[0129] For example, the deterioration of the interface properties between the cover layer CPL and the second electrode EL2 caused by the movement of the metal dopant DMT due to long-term exposure to ultraviolet light (UV) or long-term use in an external environment can be improved. In an embodiment, the volume ratio of the metal dopant DMT in the region adjacent to the cover layer CPL may be less than the average volume ratio of the metal dopant DMT in the entire region of the second electrode EL2. Therefore, the damage to the interface due to the movement of the metal dopant DMT towards the interface and subsequent exciton quenching can be minimized to prevent a decrease in optical efficiency and the service life of the device. In an embodiment, the metal dopant DMT may be included in the region adjacent to the cover layer CPL at a relatively low volume ratio, so as to minimize the movement of the metal dopant DMT towards the interface with the adjacent layer. Therefore, the roughness of the interface can be kept uniform to prevent diffuse reflection, etc., thereby producing excellent optical properties and light efficiency characteristics.

[0130] The average volume ratio of the metal dopant DMT in the second electrode EL2 may be less than or equal to about 30%. For example, with respect to the volume (100) of the metal host HSM and the total metal dopant DMT constituting the entirety of the second electrode EL2, the volume ratio of the metal dopant DMT may be less than or equal to about 30%. In an embodiment, the average volume ratio of the metal dopant DMT may be greater than or equal to about 3%. For example, in an embodiment, the average volume ratio of the metal dopant DMT may be in the range of about 3% to about 10%.

[0131] In an embodiment, when the metal host HSM is Ag and the metal dopant DMT is Mg, the average volume ratio of Mg in the second electrode EL2 can be in the range of about 3% to about 10%.

[0132] The second electrode EL2 may include a first region ELR-T, a second region ELR-B, and a third region ELR-M. The first region ELR-T includes a first surface US_EL2 in contact with the capping layer CPL, and the second region ELR-B includes a second surface BS_EL2 in contact with the light-emitting structure EU ( Figure 5 ). The third region ELR-M is disposed between the first region ELR-T and the second region ELR-B. The thickness of the first region ELR-T and the thickness of the second region ELR-B may both be less than one-third of the total thickness of the second electrode EL2 in the third direction DR3. In an embodiment, the second electrode EL2 may have a thickness in the range of about 50 Å to about 300 Å. Since the second electrode EL2 has a thickness in the range of about 50 Å to about 300 Å, the second electrode EL2 may have optical properties of high transmittance and low surface resistance.

[0133] In Figure 6B , the thickness direction may be the direction in the third direction DR3. Referring to Figure 6A and Figure 6B , the ratio of the metal dopant DMT may gradually decrease along the third direction DR3 as the thickness direction. In Figure 6B and the following drawings, the doping concentration is used in the same meaning as the volume ratio of the metal dopant DMT.

[0134] Referring to Figure 6B , in an embodiment, the doping concentration of the metal dopant DMT may decrease from the second region ELR-B to the first region ELR-T. In the embodiment shown in Figure 6B , the doping concentration of the metal dopant DMT may gradually decrease from about 15% to about 5%, and the average volume ratio of the metal dopant DMT in the second electrode EL2 may be about 10%. Figure 6B Shows the distribution of the doping concentration of the metal dopant DMT in the second electrode EL2 as an embodiment.

[0135] The doping concentration of the metal dopant DMT can be adjusted by changing the deposition rate of the material used for deposition. The volume ratio of the metal host HSM and the metal dopant DMT can be determined according to the ratio of the respective deposition rates of the metal host HSM and the metal dopant DMT. For example, in Figure 6BIn the embodiment shown, the ratio of the deposition rate of the metal host HSM to the metal dopant DMT can be changed from about 0.85 (Å / sec):0.15 (Å / sec) to about 0.95 (Å / sec):0.05 (Å / sec).

[0136] Figure 7A is a graph showing the doping concentration of the metal dopant in the second electrode in the thickness direction in the example shown, Figure 7B is a graph showing the doping concentration of the metal dopant in the second electrode in the thickness direction in the comparative example. Figure 7A and Figure 7B The thickness direction in can correspond to Figure 6A the third direction DR3 in. In Figure 7A and Figure 7B 0 Å on the horizontal axis indicated in the thickness direction corresponds to the interface between the electron injection layer EIL ( Figure 6A ) and the second electrode EL2 ( Figure 6A ), and in Figure 7A and Figure 7B 100 Å on the horizontal axis indicated in the thickness direction corresponds to the interface between the second electrode EL2 ( Figure 6A ) and the capping layer CPL ( Figure 6A ).

[0137] In Figure 7A and Figure 7B both, the average volume ratio of the metal dopant in the second electrode is 6.4%. Figure 7A shows an example in which the second electrode is formed in the direction in which the doping concentration of the metal dopant gradually decreases along the thickness direction, and Figure 7B shows a comparative example in which the doping concentration of the metal dopant remains at a uniform level throughout the thickness.

[0138] Figure 7C is a graph showing a comparison of the transmittance characteristics in the example and the comparative example. Referring to Figure 7C , in the transmittance characteristics, an example in which the deposition rate of the metal dopant is changed such that the volume ratio of the metal dopant in the region adjacent to the capping layer in the second electrode is less than the average volume ratio is shown to be similar to a comparative example in which the metal dopant is deposited at a uniform deposition rate. In the embodiment, the second electrode can have a transmittance of greater than or equal to about 70% at about 550 nm. Therefore, the second electrode can be used as a transmissive electrode or a transmissive-reflective electrode.

[0139] Figure 7D is a graph showing the reflectance characteristics of the second electrode according to the embodiment having Figure 7A the doping concentration distribution. Referring to Figure 7D, in an embodiment, the reflectivity of the second electrode may be less than or equal to about 30% at about 550 nm.

[0140] For example, a light-emitting element including a second electrode according to an embodiment formed by changing the doping concentration ratio of a metal dopant according to the thickness position may have high transmittance and low reflectivity, and may be used as an upper electrode material of a top-emission light-emitting element. In an embodiment, a light-emitting element having a second electrode according to an embodiment may have optical properties similar to those of a comparative example of a light-emitting element having a metal dopant with a uniform doping concentration in the second electrode.

[0141] Having Figure 7A The second electrode EL2 according to an embodiment having a metal dopant doping profile may have a sheet resistance of about 11 (Ω / sq). This corresponds to electrical properties similar to those of a comparative example of a light-emitting element having a metal dopant with a uniform doping concentration in the second electrode.

[0142] The light-emitting element of an embodiment may include a second electrode in which the volume ratio of the metal dopant in a region including a surface directly disposed under and in contact with the cover layer is less than the average volume ratio, and thus may have electrical and optical properties similar to those of a second electrode in which the metal dopant is uniformly disposed throughout the region of the second electrode. In an embodiment, in the light-emitting element of an embodiment, a metal dopant with a relatively low doping concentration may be disposed in a region adjacent to the interface with the cover layer, so that the movement or migration of the metal dopant toward the interface with the cover layer during long-term exposure to the outside or exposure to a UV environment can be minimized to prevent element degradation and a reduction in luminous efficiency, thereby resulting in excellent reliability.

[0143] In an embodiment, a display device of an embodiment including a light-emitting element having a structure of a second electrode according to an embodiment as shown in Figure 6A etc. may have excellent display quality and improved reliability.

[0144] Hereinafter, a light-emitting element according to an embodiment will be described with reference to Figures 8 to 11B . In the Figures 8 to 11B description, content repeated with the embodiment described with reference to Figures 1 to 7D will not be described again, and differences will be described.

[0145] Figure 8 is a schematic cross-sectional view enlarging a part of a light-emitting element according to an embodiment. Figure 8 The region XX'-1 in Figure 5 may correspond to the region XX' in

[0146] Referring to Figure 8, in the light-emitting element of the embodiment, the second electrode EL2-a may include a first region ELR-T1, a second region ELR-B1, and a third region ELR-M1. The first region ELR-T1 includes a first surface US_EL2 in contact with the cover layer CPL. The second region ELR-B1 includes a second surface BS_EL2 in contact with the light-emitting structure EU ( Figure 5 ). The third region ELR-M1 is disposed between the first region ELR-T1 and the second region ELR-B1.

[0147] The metal dopant DMT may be distributed throughout the first region ELR-T1, the second region ELR-B1, and the third region ELR-M1. The volume ratio of the metal dopant DMT in the first region ELR-T1 and the second region ELR-B1 may be less than the average volume ratio of the metal dopant DMT in the second electrode EL2-a. In the embodiment, the volume ratio of the metal dopant in the third region ELR-M1 may be greater than the average volume ratio of the metal dopant DMT in the second electrode EL2-a.

[0148] The second electrode EL2-a may be formed by using thermal evaporation to co-deposit the metal host HSM and the metal dopant DMT. The ratio of the deposition rates of the metal host HSM and the metal dopant DMT may vary in the second region ELR-B1, the third region ELR-M1, and the first region ELR-T1 of the second electrode EL2-a according to the embodiment shown in Figure 8 . In the embodiment, the deposition rate of the metal dopant DMT in the third region ELR-M1 may be greater than the deposition rate of the metal dopant DMT in each of the first region ELR-T1 and the second region ELR-B1. Therefore, the concentration (volume ratio) of the metal dopant DMT in the third region ELR-M1 of the second electrode EL2-a may be greater than the concentration (volume ratio) of the metal dopant DMT in each of the first region ELR-T1 and the second region ELR-B1 of the second electrode EL2-a.

[0149] Figure 9A is a graph showing the doping concentration distribution of the second electrode having the structure of the embodiment shown in Figure 8 along the thickness direction in the light-emitting element. Figure 9B is a graph showing the transmittance characteristics of an example having the doping concentration distribution shown in Figure 9A .

[0150] Refer to Figure 9A, the doping concentration of the metal dopant of the second electrode in the embodiment in the thickness direction may have a distribution in which the middle portion is formed into a convex shape. In an embodiment, the average doping concentration of the metal dopant DMT in the second electrode CL2-a may be about 14%, and the second region ELR-B1 and the first region ELR-T1 may have a doping concentration lower than the average doping concentration of 14%. In an embodiment, the third region ELR-M1 may have a doping concentration higher than the average doping concentration of 14%. Having Figure 9A The doping concentration distribution of the second electrode EL2-a shown in FIG. Figure 8 ) can have a deposition rate of the metal dopant DMT less than or equal to about 0.14 (Å / sec) in the second region ELR-B1, a deposition rate of the metal dopant DMT greater than or equal to about 0.14 (Å / sec) in the third region ELR-M1, and a deposition rate of the metal dopant DMT less than or equal to about 0.14 (Å / sec) in the first region ELR-T1.

[0151] Figure 9B The transmittance characteristics of an embodiment in which the deposition rate of the metal dopant is changed so that the volume ratio of the metal dopant in the region adjacent to the cap layer and in the region adjacent to the light emitting structure in the second electrode is less than the average volume ratio are shown. Figure 9A In an embodiment of a metal dopant doping concentration distribution of , the second electrode may have a transmittance greater than or equal to about 70% at about 550 nm. Therefore, the second electrode may be used as a transmissive electrode or a transflective electrode.

[0152] In an embodiment, a ratio of the metal dopant DMT in a region adjacent to the cap layer CPL and a ratio of the metal dopant DMT in a region adjacent to the electron injection layer EIL may be smaller than a ratio of the metal dopant DMT in other regions of the second electrode EL2-a, thereby minimizing the diffusion of the metal dopant DMT having a smaller work function and a relatively small atomic diameter than the metal body HSM into an adjacent layer or an interface with an adjacent layer.

[0153] Therefore, it is possible to improve the deterioration of the interface properties between the capping layer CPL and the second electrode EL2-a and the deterioration of the interface properties between the electron injection layer EIL and the second electrode EL2-a caused by the movement of the metal dopant DMT due to long-term exposure to ultraviolet rays (UV) or long-term use in an external environment. In an embodiment, the volume ratio of the metal dopant DMT in the region adjacent to the capping layer CPL and the region adjacent to the electron injection layer EIL may be less than the average volume ratio of the metal dopant DMT in the second electrode EL2-a, and thus, the damage to the interface due to the movement of the metal dopant DMT toward the interface and subsequent exciton quenching can be minimized to prevent a reduction in optical efficiency and the service life of the device. In an embodiment, the metal dopant DMT may be included in the region adjacent to the capping layer CPL or the electron injection layer EIL at a relatively low volume ratio, thereby minimizing the movement of the metal dopant DMT toward the interface with the adjacent layer. Therefore, the roughness of the interface can be kept uniform to prevent diffuse reflection, etc., thereby producing excellent optical properties and light efficiency characteristics. For example, the second electrode EL2-a according to an embodiment may have excellent transmittance characteristics and excellent reliability characteristics even when used for a long time or exposed to an external environment such as ultraviolet rays.

[0154] Figure 10 is a schematic cross-sectional view showing an enlarged part of a light-emitting device according to an embodiment. Figure 10 The region XX'-2 in Figure 5 may correspond to the region XX' in

[0155] Referring to Figure 10 , in the light-emitting device of the embodiment, the second electrode EL2-b may include a first region ELR-T2, a second region ELR-B2, and a third region ELR-M2. The first region ELR-T2 includes a first surface US_EL2 in contact with the capping layer CPL, the second region ELR-B2 includes a second surface BS_EL2 in contact with the light-emitting structure EU ( Figure 5 ), and the third region ELR-M2 is disposed between the first region ELR-T2 and the second region ELR-B2. In an embodiment, the volume ratio of the metal dopant DMT in the third region ELR-M2 may be greater than each of the volume ratio of the metal dopant DMT in the first region ELR-T2 and the volume ratio of the metal dopant DMT in the second region ELR-B2.

[0156] The volume ratio of the metal dopant DMT in the first region ELR-T2 and the volume ratio of the metal dopant DMT in the second region ELR-B2 may both be less than the average volume ratio of the metal dopant DMT in the entire second electrode EL2-b.

[0157] In an embodiment, the third region ELR-M2 may include at least one sub-region in which the volume ratio of the metal dopant DMT is less than the average volume ratio of the metal dopant DMT in the entire second electrode EL2-b.

[0158] In Figure 10 the embodiment shown, the third region ELR-M2 may include a first sub-region SPT-b in which the volume ratio of the metal dopant DMT is less than the average volume ratio of the metal dopant DMT in the entire second electrode EL2-b, a second sub-region SPT-a disposed between the first region ELR-T2 and the first sub-region SPT-b and in which the volume ratio of the metal dopant DMT is greater than the average volume ratio of the metal dopant DMT in the entire second electrode EL2-b, and a third sub-region SPT-c disposed between the second region ELR-B2 and the first sub-region SPT-b and in which the volume ratio of the metal dopant DMT is greater than the average volume ratio of the metal dopant DMT in the entire second electrode EL2-b.

[0159] The metal dopant DMT may be distributed throughout the first region ELR-T2, the second region ELR-B2, and the third region ELR-M2. The volume ratio of the metal dopant in the first region ELR-T2 and the second region ELR-B2 may be less than the average volume ratio of the metal dopant DMT in the second electrode EL2-b. In an embodiment, the volume ratio of the metal dopant in the first sub-region SPT-b of the third region ELR-M2 may be less than the average volume ratio of the metal dopant DMT in the second electrode EL2-b. In an embodiment, the volume ratio of the metal dopant in the second sub-region SPT-a and the third sub-region SPT-c of the third region ELR-M2 may be greater than the average volume ratio of the metal dopant DMT in the second electrode EL2-b.

[0160] The second electrode EL2-b may be formed by using thermal evaporation to co-deposit a metal host HSM and a metal dopant DMT. The ratio of the deposition rates of the metal host HSM and the metal dopant DMT may vary in the second region ELR-B2, the third region ELR-M2, and the first region ELR-T2 of the second electrode EL2-b according to Figure 10 the embodiment shown.

[0161] When forming the second electrode EL2-b included in the light-emitting element of the embodiment, the deposition rate of the metal dopant DMT may be relatively low in the first region ELR-T2, the second region ELR-B2, and the first sub-region SPT-b, and relatively high in the second sub-region SPT-a and the third sub-region SPT-c.

[0162] Therefore, the concentration (volume ratio) of the metal dopant DMT in the second sub-region SPT-a and the third sub-region SPT-c of the second electrode EL2-b can be greater than the concentration (volume ratio) of the metal dopant DMT in each of the first region ELR-T2, the second region ELR-B2, and the first sub-region SPT-b of the second electrode EL2-b.

[0163] Figure 11A is a graph showing the doping concentration distribution along the thickness direction of the second electrode having the structure of the embodiment shown in Figure 10 in the light-emitting element. Figure 11B is a graph showing the transmittance characteristics having an example of the doping concentration distribution shown in Figure 11A in.

[0164] Referring to Figure 11A , the doping concentration of the metal dopant along the thickness direction in the second electrode in the embodiment can have a distribution including at least one concave region in the third region ELR-M2. Accordingly, the third region ELR-M2 can include at least one point where the volume ratio of the metal dopant is the largest on both sides of the center of the second electrode EL2-b. For example, the portion having a relatively high ratio of the metal host HSM in the second electrode EL2-b may not be concentrated at the center of the third region ELR-M2, but may be dispersedly located with a concentration distribution. Accordingly, the phenomenon in which the metal host HSM is excessively concentrated and aggregated in one portion can be further improved.

[0165] In the embodiment, the third region ELR-M2 can include at least one sub-region SPT-b having a doping concentration of the metal dopant lower than the average doping concentration and sub-regions SPT-a and SPT-c having doping concentrations of the metal dopant higher than the average doping concentration on both sides of the at least one sub-region SPT-b.

[0166] In Figure 11A the embodiment, the average doping concentration of the metal dopant in the second electrode EL2-b can be about 13%, and the second region ELR-B2 and the first region ELR-T2 can have doping concentrations lower than the average doping concentration of 13%. In the embodiment, the first sub-region SPT-b can have a doping concentration lower than the average doping concentration of 13%. In the embodiment, the third region ELR-M2 can have a doping concentration higher than the average doping concentration of 13%, and the second sub-region SPT-a and the third sub-region SPT-c provided on both sides of the first sub-region SPT-b can both have doping concentrations higher than the average doping concentration of 13%.

[0167] The second electrode EL2-b having the doping concentration distribution shown in Figure 11A in Figure 10It may have a deposition rate of metal dopant DMT less than or equal to about 0.13 (Å / sec) in the second region ELR-B2, a deposition rate of metal dopant DMT greater than or equal to about 0.13 (Å / sec) in the third sub-region SPT-c, a deposition rate of metal dopant DMT less than or equal to about 0.13 (Å / sec) in the first sub-region SPT-b, a deposition rate of metal dopant DMT greater than or equal to about 0.13 (Å / sec) in the second sub-region SPT-a, and a deposition rate of metal dopant DMT less than or equal to about 0.13 (Å / sec) in the first region ELR-T2.

[0168] Figure 11B shows the transmittance characteristics of an embodiment in which the deposition rate of the metal dopant is changed such that the volume ratio of the metal dopant in the region adjacent to the capping layer and in the region adjacent to the light-emitting structure in the second electrode is less than the average volume ratio. In an embodiment having Figure 11A the metal dopant doping concentration profile, the second electrode may have a transmittance greater than or equal to about 70% at about 550 nm. Thus, the second electrode can be used as a transmissive electrode or a transmissive-reflective electrode.

[0169] In an embodiment, the ratio of the metal dopant DMT in the region adjacent to the capping layer CPL and the ratio of the metal dopant DMT in the region adjacent to the electron injection layer EIL may be less than the average volume ratio of the metal dopant in the second electrode EL2-b. Thus, the diffusion of the metal dopant DMT having a work function smaller than that of the metal host HSM and a relatively small atomic diameter into the adjacent layer or the interface with the adjacent layer can be minimized.

[0170] Therefore, it is possible to improve the deterioration of the interfacial properties between the capping layer CPL and the second electrode EL2-b and the deterioration of the interfacial properties between the electron injection layer EIL and the second electrode EL2-b caused by the movement of the metal dopant DMT due to long-term exposure to ultraviolet rays (UV) or long-term use in an external environment. In an embodiment, the volume ratio of the metal dopant DMT in the region adjacent to the capping layer CPL and the region adjacent to the electron injection layer EIL may be less than the average volume ratio of the metal dopant DMT in the second electrode EL2-b, and thus, the damage to the interface due to the movement of the metal dopant DMT to the interface and subsequent exciton quenching can be minimized to prevent a reduction in optical efficiency and the service life of the device. In an embodiment, the metal dopant DMT may be included in the region adjacent to the capping layer CPL or the electron injection layer EIL at a relatively low volume ratio, so as to minimize the movement of the metal dopant DMT to the interface with the adjacent layer. Therefore, the roughness of the interface can be kept uniform to prevent diffuse reflection, etc., thereby producing excellent optical properties and light efficiency characteristics. For example, the second electrode EL2-b according to an embodiment may have excellent transmittance characteristics and excellent reliability characteristics even during long-term use or exposure to an external environment such as ultraviolet rays.

[0171] An embodiment of a light-emitting device having the structure of the second electrode according to an embodiment described with reference to Figures 8 to 11B may be included in a display device of the embodiment described with reference to Figures 1 to 4 Therefore, by adjusting the doping concentration of the metal dopant in the second electrode according to the thickness position and changing the volume ratio of the metal dopant, a display device of an embodiment including the light-emitting device of the embodiment may have excellent display quality and improved reliability.

[0172] In the light-emitting device of the embodiment, a metal dopant other than the metal main body may be included in the second electrode provided under the capping layer, and thus, the aggregation phenomenon of the metal main body can be improved. In an embodiment, the volume ratio of the metal dopant may be relatively low in the region adjacent to the capping layer to improve the interfacial characteristics between the capping layer and the second electrode, thereby showing excellent device characteristics and improved reliability characteristics.

[0173] In an embodiment, the display device of the embodiment may include a light-emitting device in a display element layer and an electrode in the light-emitting device in which the volume ratio of the metal dopant is relatively low in the region adjacent to the capping layer, and thus, may also have improved reliability and maintain excellent display quality.

[0174] By making the concentration of the metal dopant in the region adjacent to the upper surface lower than the average concentration of the metal dopant in the layer, the light-emitting device of the embodiment can maintain both excellent device performance and optical properties and have improved reliability.

[0175] The display device of the embodiment may include a light-emitting element having a dopant with an optimized ratio in the electrode, and thus may have excellent display quality and improved reliability.

[0176] The above description is an example of the disclosed technical features, and those skilled in the art to which the present disclosure pertains will be able to make various modifications and variations. Therefore, the disclosed embodiments described above can be implemented individually or in combination with each other.

[0177] Therefore, the embodiments disclosed in the disclosure are not intended to limit the technical spirit of the disclosure, but to describe the technical spirit of the disclosure, and the scope of the technical spirit of the disclosure is not limited by these embodiments. The protection scope of the disclosure should be interpreted by the appended claims and should be interpreted to include all technical spirits within the equivalent scope in the scope of the disclosure.

Claims

1. A light-emitting element, the light-emitting element comprising: A first electrode; A light-emitting structure disposed on the first electrode and including an emission layer; A second electrode disposed on the light-emitting structure and including silver and a metal dopant; And A cover layer directly disposed on the second electrode, wherein An average volume ratio of the metal dopant in the second electrode is less than or equal to 30%, and A volume ratio of the metal dopant in a region adjacent to the cover layer is less than the average volume ratio of the metal dopant in the second electrode.

2. The light-emitting element according to claim 1, wherein, The metal dopant includes at least one of Al, Au, Cu, Mg, Ti, In, Ni, C, Pd, F, Na, Si, Ca, Mn, Fe, Co, Zn, Ga, Ge, Mo, Sn, In, Pt, Pb, Fe, Yb, Lu, and Pa.

3. The light-emitting element according to claim 1, wherein The metal dopant is Mg, and The average volume ratio of the metal dopant in the second electrode is in a range of 3% to 10%.

4. The light-emitting element according to claim 1, wherein, The volume ratio of the metal dopant in the second electrode gradually decreases in a direction from the light-emitting structure to the cover layer.

5. The light-emitting element according to claim 1, wherein, The second electrode has a thickness in a range of 50 Å to 300 Å.

6. The light-emitting element according to claim 1, wherein, The second electrode is formed by co-depositing silver and the metal dopant using a thermal evaporation method.

7. The light-emitting element according to claim 1, wherein The second electrode includes a first region, a second region, and a third region. The first region includes a first surface in contact with the cover layer, the second region includes a second surface in contact with the light-emitting structure, the third region is disposed between the first region and the second region, and A first volume ratio of the metal dopant in the first region and a second volume ratio of the metal dopant in the second region are both less than the average volume ratio of the metal dopant in the second electrode.

8. The light-emitting element according to claim 7, wherein, A third volume ratio of the metal dopant in the third region is greater than the average volume ratio of the metal dopant in the second electrode.

9. The light-emitting element according to claim 7, wherein, The third region includes: A first sub-region having the third volume ratio of the metal dopant, the third volume ratio of the metal dopant being less than the average volume ratio of the metal dopant in the second electrode; A second sub-region disposed between the first region and the first sub-region and having a fourth volume ratio of the metal dopant, the fourth volume ratio of the metal dopant being greater than the average volume ratio of the metal dopant in the second electrode; and A third sub-region disposed between the second region and the first sub-region and having a fifth volume ratio of the metal dopant, the fifth volume ratio of the metal dopant being greater than the average volume ratio of the metal dopant in the second electrode.

10. The light-emitting element according to claim 7, wherein, The third region includes at least one sub-region having the third volume ratio of the metal dopant, the third volume ratio of the metal dopant being less than the average volume ratio of the metal dopant in the second electrode.

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