Light emitting element and display device including same

Abstract

The invention relates to a light emitting element and a display device including the same. The light-emitting element includes: a first electrode; a second electrode facing the first electrode; and a plurality of light emitting structures stacked between the first electrode and the second electrode, each of the plurality of light emitting structures including a hole transport region, a light emitting layer, and an electron transport region. At least one of the plurality of light emitting structures is a green light emitting structure emitting green light, and a light emitting layer of the green light emitting structure includes: a first sub-light emitting layer including a low refractive index material having a refractive index value of less than or equal to about 1.7 at a wavelength of 460 nm; and a second sub-emission layer not including a low refractive index material and disposed on the first sub-emission layer, whereby the light-emitting element may exhibit high luminous efficiency.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0093694 filed in the Korean Intellectual Property Office (KIPO) on July 19, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure herein relates to a light emitting element having a plurality of stacked light emitting structures and a display device including the same. Background Art

[0004] Various display devices are being developed for multimedia devices such as televisions, mobile phones, tablet computers, and game consoles. In such display devices, so-called self-luminous display elements are used, which realize display by allowing a light-emitting material including an organic compound or quantum dots, etc., to emit light in a light-emitting layer provided between electrodes facing each other.

[0005] When a light emitting element is applied to a display device, the light emitting element is required to have high light emission efficiency and a long life, and there is a continuous demand for stably achieving the above-described development of materials for the light emitting element and a stack structure of the light emitting element. Summary of the invention

[0006] The present disclosure provides a light emitting element having excellent light extraction efficiency and improved light emitting efficiency.

[0007] The present disclosure also provides a display device including a light emitting element having high light emitting efficiency.

[0008] In an embodiment of the present disclosure, a light-emitting element may include: a first electrode; a second electrode facing the first electrode; and a plurality of light-emitting structures stacked between the first electrode and the second electrode, each of the plurality of light-emitting structures including a hole transport region, a light-emitting layer, and an electron transport region. At least one of the plurality of light-emitting structures may be a green light-emitting structure that emits green light. The light-emitting layer of the green light-emitting structure may include: a first sub-light-emitting layer including a low-refractive index material having a refractive index value less than or equal to about 1.7 at a wavelength of 460 nm; and a second sub-light-emitting layer that does not include the low-refractive index material and is disposed on the first sub-light-emitting layer.

[0009] In an embodiment, the first sub-light emitting layer and the second sub-light emitting layer may each include a hole transporting first host, an electron transporting second host, and a green light emitting dopant.

[0010] In embodiments, the low refractive index material may be a hole transporting host.

[0011] In an embodiment, the first sub-light emitting layer may be directly disposed on the hole transport region of the green light emitting structure.

[0012] In an embodiment, the hole transport region of the green light emitting structure may include: a hole transport layer; and an auxiliary hole transport layer disposed on the hole transport layer and including a low refractive index hole transport material having a refractive index value less than or equal to about 1.7 at a wavelength of 460 nm.

[0013] In an embodiment, the first sub-light emitting layer may be directly disposed on the auxiliary hole transport layer.

[0014] In an embodiment, the low refractive index material and the low refractive index hole transport material may be the same.

[0015] In an embodiment, the plurality of light emitting structures may include a first light emitting structure disposed on the first electrode and emitting blue light, a second light emitting structure disposed on the first light emitting structure and emitting blue light, a third light emitting structure disposed on the second light emitting structure and emitting blue light, and a green light emitting structure disposed on the third light emitting structure.

[0016] In an embodiment, the light emitting layer of each of the first, second, and third light emitting structures may include a hole transport host, an electron transport host, and a blue light emitting dopant.

[0017] In an embodiment, the plurality of light emitting structures may include a first light emitting structure disposed on the first electrode and emitting blue light, a second light emitting structure disposed on the first light emitting structure and emitting blue light, and a green light emitting structure disposed on the second light emitting structure.

[0018] In an embodiment, the plurality of light emitting structures may include a first light emitting structure, a second light emitting structure, a third light emitting structure, and a fourth light emitting structure, each emitting blue light and sequentially stacked between a first electrode and a second electrode. The green light emitting structure may include a first green light emitting structure disposed between the second light emitting structure and the third light emitting structure and a second green light emitting structure disposed on an upper side of the fourth light emitting structure. The second green light emitting structure may include a first sub-light emitting layer having a low refractive index material and a second sub-light emitting layer not including a low refractive index material.

[0019] In an embodiment, the first sub light emitting layer and the second sub light emitting layer may have the same thickness.

[0020] In an embodiment of the present disclosure, a light-emitting element may include: a first electrode; a second electrode facing the first electrode; a plurality of light-emitting structures sequentially stacked between the first electrode and the second electrode, each of the plurality of light-emitting structures including a hole transport region, a light-emitting layer, and an electron transport region; and a charge generation layer disposed between adjacent light-emitting structures of the plurality of light-emitting structures between the first electrode and the second electrode. Two or more of the plurality of light-emitting structures may be blue light-emitting structures that emit blue light, and at least one of the plurality of light-emitting structures may be a green light-emitting structure that emits green light. The green light-emitting structure may include: a first sub-light-emitting layer including a first host, a first dopant, and a low refractive index material having a refractive index value less than or equal to about 1.7 at a wavelength of 460 nm; and a second sub-light-emitting layer disposed on the first sub-light-emitting layer and including a second host and a second dopant.

[0021] In an embodiment, the charge generation layer may include an n-type charge generation layer doped with an n-type dopant and a p-type charge generation layer doped with a p-type dopant.

[0022] In an embodiment, the second sub-light emitting layer may not include a low refractive index material, the first host and the second host may be the same, and the first dopant and the second dopant may be the same.

[0023] In an embodiment, the plurality of light emitting structures may include a first blue light emitting structure disposed on the first electrode, a second blue light emitting structure disposed on the first blue light emitting structure, a third blue light emitting structure disposed on the second blue light emitting structure, and a green light emitting structure disposed on the third blue light emitting structure.

[0024] In an embodiment, the hole transport region of the green light emitting structure may include an auxiliary hole transport layer, which is directly disposed at a lower side of the first sub-light emitting layer and includes a low refractive index hole transport material having a refractive index value less than or equal to about 1.7 at a wavelength of 460nm.

[0025] In an implementation, light emitted from the plurality of light emitting structures may be emitted to an upper side of the second electrode.

[0026] In an embodiment, among the plurality of light emitting structures, a green light emitting structure may be disposed adjacent to the second electrode.

[0027] In an embodiment, the light emitting layer of each of the first, second, and third blue light emitting structures may not include a low refractive index material.

[0028] In an embodiment of the present disclosure, a display device may include: a light-emitting element that outputs source light; and an optical layer that is disposed on the light-emitting element and transmits the source light or converts the wavelength of the source light. The light-emitting element may include: a first electrode; a second electrode facing the first electrode; and a plurality of light-emitting structures stacked between the first electrode and the second electrode, each of the plurality of light-emitting structures including a hole transport region, a light-emitting layer, and an electron transport region. At least one of the plurality of light-emitting structures may be a green light-emitting structure that emits green light. The light-emitting layer of the green light-emitting structure may include: a first sub-light-emitting layer including a low-refractive index material having a refractive index value less than or equal to about 1.7 at a wavelength of 460 nm; and a second sub-light-emitting layer that does not include the low-refractive index material and is disposed on the first sub-light-emitting layer.

[0029] In an embodiment, the optical layer may include a light management layer including quantum dots that convert the wavelength of the source light.

[0030] In an embodiment, the light emitting element may further include a first pixel region emitting red light, a second pixel region emitting green light, and a third pixel region emitting blue light. The first pixel region, the second pixel region, and the third pixel region may not overlap with each other in a plan view. The light control layer may include: a first light control component, which is arranged corresponding to the first pixel region and includes a first quantum dot that converts the wavelength of the source light; a second light control component, which is arranged corresponding to the second pixel region and includes a second quantum dot that converts the wavelength of the source light; and a third light control component, which is arranged corresponding to the third pixel region.

[0031] In embodiments, the low refractive index material may be a hole transporting host.

[0032] In an embodiment, the hole transport region of the green light emitting structure may include: a hole injection layer; a hole transport layer disposed on the hole injection layer; and an auxiliary hole transport layer disposed on the hole transport layer and including a low refractive index hole transport material having a refractive index value less than or equal to about 1.7 at a wavelength of 460 nm. The first sub-light emitting layer may be directly disposed on the auxiliary hole transport layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated into and constitute a part of this specification. The accompanying drawings illustrate embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure. In the drawings:

[0034] Figure 1A is a perspective view of a display device according to an embodiment of the present disclosure;

[0035] Figure 1B is a schematic cross-sectional view of a display device according to an embodiment of the present disclosure;

[0036] Figure 1Cis a plan view of a display device according to an embodiment of the present disclosure;

[0037] Figure 2 A plan view showing an enlarged portion of a display device according to an embodiment of the present disclosure;

[0038] Figure 3 is a schematic cross-sectional view of a portion of a display device according to an embodiment of the present disclosure;

[0039] Figure 4A is a schematic cross-sectional view of a portion of a display device according to an embodiment of the present disclosure;

[0040] Figure 4B is a schematic cross-sectional view of a portion of a display device according to an embodiment of the present disclosure;

[0041] Figure 4C is a schematic cross-sectional view of a portion of a display device according to an embodiment of the present disclosure;

[0042] Figure 5 is a schematic cross-sectional view of a light emitting element according to an embodiment of the present disclosure;

[0043] Fig. 6A is a schematic cross-sectional view of a light emitting structure according to an embodiment of the present disclosure;

[0044] Figure 6B is a schematic cross-sectional view of a light emitting structure according to an embodiment of the present disclosure;

[0045] Fig. 7A is a schematic cross-sectional view of a light emitting structure according to an embodiment of the present disclosure;

[0046] Figure 7B is a schematic cross-sectional view of a light emitting structure according to an embodiment of the present disclosure;

[0047] Figure 8 is a schematic cross-sectional view of a light emitting element according to an embodiment of the present disclosure; and

[0048] Fig. 9 Schematic cross-sectional view of a light emitting element according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0049] The present disclosure can be modified in many alternative forms, and therefore specific embodiments will be illustrated and described in detail in the drawings. However, it should be understood that it is not intended to limit the present disclosure to the specific form disclosed, but is intended to cover all modifications, equivalents and alternatives that fall within the spirit and scope of the present disclosure.

[0050] When an element or layer is referred to as being "on," "connected to," or "coupled to" another element or layer, it may be directly on, directly connected to, or directly coupled to another element or layer, or there may 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 purpose, the term "connected" may refer to a physical connection, an electrical connection, and / or a fluid connection with or without intervening elements. Furthermore, when an element is referred to as being "in contact," "contacted," etc., with another element, the element may be "electrically in contact" or "physically in contact" with the other element; or "indirectly in contact" or "directly in contact" with the other element.

[0051] The same reference numerals refer to the same elements. In addition, in the drawings, the proportions and sizes (eg, thickness) of the elements are exaggerated for the effective description of the technical content. The term "and / or" includes any and all combinations in which one or more related elements can be defined.

[0052] 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 element. For example, a first element may be referred to as a second element, and in a similar manner a second element may be referred to as a first element without departing from the scope of the present disclosure. Terms in the singular may include plural forms unless the context clearly indicates otherwise.

[0053] In addition, terms such as "below", "lower", "above", and "upper" are used to describe the relationship of elements shown in the drawings. These terms are used as relative concepts and are described with reference to directions indicated in the drawings.

[0054] It should be understood that the terms “comprise” or “have” are intended to indicate the presence of the recited features, integers, steps, operations, elements, components, or any combination thereof in the present disclosure, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or any combination thereof.

[0055] In the present disclosure, "directly disposed" may mean that no layer, film, region, plate, etc. is added between a portion and other portions of the layer, film, region, plate, etc. For example, "directly disposed" may mean disposed without an additional member (such as an adhesive member) between two layers or two members.

[0056] In the specification and claims, the phrase "at least one of..." is intended to include the meaning of "at least one selected from the group of..." for the purpose of its meaning and interpretation. For example, "at least one of A and B" may be understood to mean "A, B, or A and B". In the specification and claims, the term "and / or" is intended to include any combination of the terms "and" and "or" for the purpose of its meaning and interpretation. For example, "A and / or B" may be understood to mean "A, B, or A and B". The terms "and" and "or" may be used in a conjunctive sense or a disjunctive sense and may be understood to be equivalent to "and / or".

[0057] Unless otherwise defined, all terms (including technical and scientific terms) used in this article have the same meaning as those generally understood by ordinary technicians in the field to which the present disclosure belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with the meaning in the context of the relevant field, and should not be interpreted in an overly idealized sense or an overly formal sense, unless explicitly defined in this article.

[0058] Hereinafter, a light emitting element of an embodiment and a display device of an embodiment will be described with reference to the accompanying drawings.

[0059] Figure 1A It is a perspective view of a display device according to an embodiment of the present disclosure. Figure 1B is a schematic cross-sectional view of a display device according to an embodiment of the present disclosure. Figure 1C is a plan view of a display device according to an embodiment of the present disclosure. Figure 1B According to the embodiment of the present disclosure, Figure 1A A cross-sectional view taken along line II'.

[0060] The display device DD of the embodiment may be a device that is activated in response to an electrical signal and displays an image. For example, the display device DD may be a large device such as a television and an external billboard, and may also be a small and medium-sized device such as a monitor, a mobile phone, a tablet computer, a navigation system unit, and a game console. However, the embodiment of the display device DD is exemplary, and the display device DD is not limited to any one of the embodiments thereof without departing from the present disclosure.

[0061] The display device DD may be rigid or flexible. "Flexible" refers to having the property of being able to bend. For example, the flexible display device DD may include a bendable device, a rollable device, or a foldable device.

[0062] exist Figure 1AIn the following drawings, the first to third directional axes DR1, DR2, and DR3 are explained, and the directions indicated by the first to third directional axes DR1, DR2, and DR3 described in the specification are relative concepts and can be converted into different directions. The directions indicated by the first to third directional axes DR1, DR2, and DR3 can be described as the first to third directions DR1, DR2, and DR3, and can be represented by the same reference numerals. In the specification, the first directional axis DR1 and the second directional axis DR2 can be orthogonal to each other, and the third directional axis DR3 can be a normal direction relative to a plane defined by the first directional axis DR1 and the second directional axis DR2.

[0063] The thickness direction of the display device DD may be a direction parallel to the third directional axis DR3, which is a normal direction relative to a plane defined by the first directional axis DR1 and the second directional axis DR2. In the specification, the front surface (or upper surface) and the rear surface (or lower surface) of the member constituting the display device DD may be defined based on the third directional axis DR3. The front surface (or upper surface) and the rear surface (or lower surface) of the member constituting the display device DD may be opposite to each other in the third direction DR3, and the normal direction of each of the front surface and the rear surface may be substantially parallel to the third direction DR3. The separation distance between the front surface and the rear surface defined along the third direction DR3 may correspond to the thickness of the member.

[0064] In the specification, "on a plane" or "in a plan view" may be defined as a state observed in the third direction DR3. In the specification, "on a cross section" or "in a cross-sectional view" may be defined as a state observed in the first direction DR1 or the second direction DR2. The directions indicated by the first to third directions DR1, DR2, and DR3 are relative concepts and may be converted into different directions.

[0065] The display device DD according to the embodiment may display an image through the display surface IS. The display surface IS may include a plane defined by the first direction DR1 and the second direction DR2. The display surface IS may include a display area DA and a non-display area NDA. The pixel PX may be disposed in the display area DA, and the pixel PX may not be disposed in the non-display area NDA. The non-display area NDA may be defined along the edge of the display surface IS. The non-display area NDA may surround the display area DA. However, the present disclosure is not limited thereto, and in an embodiment of the present disclosure, the non-display area NDA may be omitted, or the non-display area NDA may be disposed only on one side of the display area DA.

[0066] In the embodiment of the present disclosure, the display device DD provided with a flat display surface IS is explained, but the present 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 indicating different directions from each other.

[0067] refer to Figure 1B The display device DD may include a base layer BS, a circuit layer DP-CL, and a display layer DP-ED sequentially stacked in the direction of the third direction axis DR3. The display device DD of the embodiment may further include an optical layer OSL disposed on the display layer DP-ED.

[0068] The base layer BS may be a supporting substrate on which the circuit layer DP-CL and the display layer DP-ED are provided. The circuit layer DP-CL may include at least one insulating layer and a circuit element. The circuit element may include a driving circuit of a signal line or a pixel, etc. The circuit layer DP-CL may be formed by a process of forming an insulating layer, a semiconductor layer and a conductive layer by coating or deposition, etc., and a process of patterning the insulating layer, the semiconductor layer and the conductive layer by a photoetching process. The display layer DP-ED may include a display element. The optical layer OSL may convert the color of light provided from the display element. The optical layer OSL may include a light control pattern and a structure for increasing light conversion efficiency.

[0069] Figure 1C The planar arrangement relationship of the signal lines GL1 to GLn and DL1 to DLm and the pixels PX11 to PXnm is explained. The signal lines GL1 to GLn and DL1 to DLm may include a plurality of gate lines GL1 to GLn and a plurality of data lines DL1 to DLm.

[0070] Each of the pixels PX11 to PXnm may be connected to a corresponding gate line among the gate lines GL1 to GLn and a corresponding data line among the data lines DL1 to DLm. Each of the pixels PX11 to PXnm may include a pixel driving circuit and a display element. According to the configuration of the pixel driving circuit of each of the pixels PX11 to PXnm, more types of signal lines may be provided in the display device DD.

[0071] The pixels PX11 to PXnm in a matrix form are explained, but the present disclosure is not limited thereto. In an embodiment, the pixels PX11 to PXnm may be arranged in a matrix form. For example, the points where the pixels PX11 to PXnm are arranged may correspond to the vertices of the rhombus. The gate driving circuit GDC may be integrated into the display device DD by an oxide silicon gate driving circuit (OSG) or an amorphous silicon gate driving circuit (ASG) process.

[0072] Figure 2 It is a plan view of an enlarged portion of a display device according to an embodiment of the present disclosure. Figure 2 The display device DD (see FIG. Figure 1A) includes a plane of three pixel regions PXA-R, PXA-G and PXA-B and a bank well region BWA adjacent thereto. In an embodiment of the present disclosure, Figure 2 The three types of pixel areas PXA-R, PXA-G and PXA-B explained in the above description may be repeatedly arranged in the entire display area DA (see Figure 1A ) The pixel regions PXA-R, PXA-G, and PXA-B may also be referred to as light-emitting regions.

[0073] Around the first to third pixel regions PXA-R, PXA-G, and PXA-B, a peripheral region NPXA may be disposed, and the peripheral region NPXA may also be referred to as a non-light emitting region.

[0074] The peripheral area NPXA may set the boundaries of the first to third pixel areas PXA-R, PXA-G, and PXA-B. The peripheral area NPXA may surround the first to third pixel areas PXA-R, PXA-G, and PXA-B. In the peripheral area NPXA, a structure for preventing color mixing between the first to third pixel areas PXA-R, PXA-G, and PXA-B may be provided, for example, a pixel defining layer PDL (see Figure 3 ) or dike BMP (see Figure 3 )wait.

[0075] exist Figure 2 , the first to third pixel regions PXA-R, PXA-G, and PXA-B having the same planar shape and different planar areas are schematically illustrated, but the present disclosure is not limited thereto. The areas of two or more pixel regions among the first to third pixel regions PXA-R, PXA-G, and PXA-B may be the same. The area of ​​each of the first to third pixel regions PXA-R, PXA-G, and PXA-B may be set according to the color of the emitted light. Among the primary colors, the area of ​​the pixel region emitting red light may be the largest, and the area of ​​the pixel region emitting blue light may be the smallest.

[0076] exist Figure 2 , the first to third pixel regions PXA-R, PXA-G, and PXA-B, each having a rectangular shape, are explained, but the present disclosure is not limited thereto. In a plan view, the first to third pixel regions PXA-R, PXA-G, and PXA-B may each have a different polygonal shape (including a substantially polygonal shape), such as a rhombus shape or a pentagonal shape. In an embodiment, the first to third pixel regions PXA-R, PXA-G, and PXA-B may have a rectangular shape (substantially a rectangular shape) including a rounded corner region in a plan view.

[0077] Figure 2It is schematically explained that the second pixel region PXA-G is arranged in the first row and the first pixel region PXA-R and the third pixel region PXA-B are arranged in the second row, but the present disclosure is not limited thereto, and the arrangement of the first to third pixel regions PXA-R, PXA-G, and PXA-B may be variously changed. For example, the first to third pixel regions PXA-R, PXA-G, and PXA-B may be arranged in the same row.

[0078] One of the first to third pixel regions PXA-R, PXA-G, and PXA-B may provide red light, another of the first to third pixel regions PXA-R, PXA-G, and PXA-B may provide green light, and the remaining one of the first to third pixel regions PXA-R, PXA-G, and PXA-B may provide blue light. In an embodiment, the first pixel region PXA-R may provide red light, the second pixel region PXA-G may provide green light, and the third pixel region PXA-B may provide blue light.

[0079] The first pixel region PXA-R may emit light having a light emission wavelength in the range of about 620 nm to about 700 nm, the second pixel region PXA-G may emit light having a light emission wavelength in the range of about 520 nm to about 600 nm, and the third pixel region PXA-B may emit light having a light emission wavelength in the range of about 410 nm to about 480 nm. The first pixel region PXA-R may be referred to as a red pixel region, the second pixel region PXA-G may be referred to as a green pixel region, and the third pixel region PXA-B may be referred to as a blue pixel region.

[0080] In the display area DA (see Figure 1A ), a bank well area BWA may be defined. The bank well area BWA may be a region where the patterned light control layer CCL (see Figure 4A ) includes a plurality of light control units CCP-R, CCP-G and CCP-B (see Figure 4A ) during the process of forming a bank well due to defects caused by erroneous adhesion. For example, the bank well area BWA may be a region in which the bank well area is defined by removing the bank BMP (see Figure 4A ) to form a portion of the bank well area.

[0081] Figure 2 It is schematically illustrated that two bank well areas BWA are disposed adjacent to the second pixel area PXA-G, but the present disclosure is not limited thereto, and the shape and arrangement of the bank well areas BWA may be variously changed.

[0082] Figure 3 is a schematic cross-sectional view of a portion of a display device according to an embodiment of the present disclosure. Figure 4A A schematic cross-sectional view of a portion of a display device for explaining an embodiment of the present disclosure. Figure 3 According to the embodiment of the present disclosure, Figure 2 A cross-sectional view taken along line II-II', and Figure 4A According to the embodiment of the present disclosure, Figure 2 A cross-sectional view taken along line III-III'.

[0083] refer to Figure 3 and Figure 4A The display device DD of the embodiment may include a base layer BS, a circuit layer DP-CL disposed on the base layer BS, and a display layer DP-ED disposed on the circuit layer DP-CL. In the specification, the stacked structure including the base layer BS, the circuit layer DP-CL, and the display layer DP-ED may be referred to as a lower panel. Figure 3 different, Figure 4A The configuration of the circuit layer DP-CL and the configuration of the encapsulation layer TFE are briefly explained, and a portion of the display device in a plurality of pixel regions is shown.

[0084] The base layer BS may be a member providing a base surface on which components included in the circuit layer DP-CL are disposed. In an embodiment, the base layer BS may be a glass substrate, a metal substrate, a polymer substrate, etc. However, the present disclosure is not limited thereto, and the base layer BS may be an inorganic layer, a functional layer, or a composite material layer.

[0085] The base layer BS may have a multilayer structure. For example, the base layer BS may have a three-layer structure of a polymer resin layer, an adhesive layer and a polymer resin layer. For example, the polymer resin layer may include a polyimide resin. In addition, the polymer resin layer may include at least one of an acrylate resin (e.g., a methacrylate resin), a polyisoprene resin, a vinyl resin, an epoxy resin, a urethane resin, a cellulose resin, a siloxane resin, a polyamide resin and a perylene resin. In the specification, an "α-type" resin means including an "α" functional group.

[0086] The circuit layer DP-CL may be disposed on the base layer BS. The circuit layer DP-CL may include a transistor TD as a circuit element. Figure 1A ) to change the configuration of the circuit layer DP-CL, and Figure 3 , one transistor TD is illustrated, and the arrangement of an active portion AD, a source SD, a drain DD, and a gate GD constituting the transistor TD is schematically illustrated. The active portion AD, the source SD, and the drain DD may be regions distinguished according to doping concentration or conductivity of a semiconductor pattern.

[0087] The circuit layer DP-CL may include a buffer layer BFL, a first insulating layer 10, a second insulating layer 20, and a third insulating layer 30 disposed on the base layer BS, etc. For example, the buffer layer BFL, the first insulating layer 10, and the second insulating layer 20 may be inorganic layers, and the third insulating layer 30 may be an organic layer.

[0088] The display layer DP-ED may include a light emitting element OEL as a display element. The light emitting element OEL may generate source light. In an embodiment, the source light may be white light or blue light. In an embodiment, the display layer DP-ED may include an organic light emitting diode as the light emitting element OEL. For example, light emitting layers EML-1, EML-2, EML-3, and EML-4 (see FIG. 1 ) included in the light emitting element OEL. Figure 5 ) may each include an organic light-emitting material as a light-emitting material.

[0089] The light emitting element OEL may include a first electrode EL1, a second electrode EL2 facing the first electrode EL1, and a light emitting stack ST disposed between the first electrode EL1 and the second electrode EL2. The light emitting stack ST may include a plurality of light emitting structures EU-1, EU-2, EU-3, and EU-4 (see Figure 5 In an embodiment, the light emitting stack ST may include three or more light emitting structures separated from each other and stacked in a thickness direction. The light emitting stack ST may include a plurality of blue light emitting structures emitting blue light and at least one green light emitting structure emitting green light.

[0090] The light emitting stack ST may include light emitting structures EU-1, EU-2, EU-3 and EU-4 (see Figure 5 ) between the charge generation layers CGL-1, CGL-2 and CGL-3 (see Figure 5 ). The light emitting structure and the charge generation layer included in the light emitting element OEL will be described in more detail below. The light emitting element OEL may further include a capping layer CPL disposed on an upper portion of the second electrode EL2.

[0091] The first electrode EL1 may be disposed on the third insulating layer 30. The first electrode EL1 may be directly or indirectly connected to the transistor TD and Figure 3 In the figure, the connection structure between the first electrode EL1 and the transistor TD is not shown. The first electrode EL1 may be an anode or a cathode. The first electrode EL1 may be a pixel electrode. The first electrode EL1 may be a transmission electrode, a transflective electrode or a reflection electrode.

[0092] The display layer DP-ED may include a pixel defining layer PDL. For example, the pixel defining layer PDL may be an organic layer. In the pixel defining layer PDL, a light emitting opening OH may be defined. The light emitting opening OH of the pixel defining layer PDL may expose at least a portion of the first electrode EL1. In an embodiment, the light emitting areas EA1, EA2, and EA3 may be defined by the light emitting opening OH.

[0093] The display layer DP-ED may include a first light emitting area EA1, a second light emitting area EA2, and a third light emitting area EA3. The first light emitting area EA1, the second light emitting area EA2, and the third light emitting area EA3 may be areas separated by a pixel defining layer PDL. The first light emitting area EA1, the second light emitting area EA2, and the third light emitting area EA3 may correspond to the first pixel area PXA-R, the second pixel area PXA-G, and the third pixel area PXA-B, respectively.

[0094] The light-emitting areas EA1, EA2, and EA3 may overlap with the pixel areas PXA-R, PXA-G, and PXA-B in a plan view and may not overlap with the bank well area BWA. In a plan view, the areas of the pixel areas PXA-R, PXA-G, and PXA-B separated by the bank BMP may be larger than the areas of the light-emitting areas EA1, EA2, and EA3 separated by the pixel defining layer PDL.

[0095] The light emitting stack ST may be disposed to overlap the pixel regions PXA-R, PXA-G, and PXA-B in a plan view. In an embodiment, the light emitting stack ST may be disposed in common in the pixel regions PXA-R, PXA-G, and PXA-B. The light emitting structures EU-1, EU-2, EU-3, and EU-4 (see FIG. Figure 5 ) can be commonly disposed in the entire pixel areas PXA-R, PXA-G and PXA-B.

[0096] However, the present disclosure is not limited thereto. Light emitting structures EU-1, EU-2, EU-3 and EU-4 (see Figure 5 ) may be separately formed in each of the first to third pixel regions PXA-R, PXA-G, and PXA-B. In an embodiment, the light emitting structures EU-1, EU-2, EU-3, and EU-4 (see Figure 5 ) may be patterned in the light emitting opening OH and individually formed in each of the first to third pixel regions PXA-R, PXA-G, and PXA-B.

[0097] The second electrode EL2 may be disposed facing the first electrode EL1, and the light emitting stack ST is inserted between the first electrode EL1 and the second electrode EL2. The second electrode EL2 may be a common electrode. The second electrode EL2 may be a cathode or an anode, but the present disclosure is not limited thereto. For example, 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 transmissive electrode, a transflective electrode, or a reflective electrode.

[0098] The display layer DP-ED may include an encapsulation layer TFE that protects the light emitting element OEL. The encapsulation layer TFE may include an organic material or an inorganic material. The encapsulation layer TFE may have a multilayer structure in which an inorganic layer / organic layer is 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 stacked in sequence. However, the layers constituting the encapsulation layer TFE are not limited thereto. The encapsulation layer TFE may be provided directly on the light emitting element OEL in a continuous process.

[0099] The first inorganic layer IOL1 and the second inorganic layer IOL2 can protect the light emitting element OEL from moisture and oxygen, and the organic layer OL can protect the light emitting element OEL from foreign matter (such as dust particles). For example, the organic layer OL can prevent the imprint defect of the light emitting element OEL caused by foreign matter introduced during the manufacturing process. Although not illustrated, the display device DD may further include a refractive index control layer disposed on the upper side of the encapsulation layer TFE for improving light emitting efficiency.

[0100] The inorganic layers IOL1 and 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 acrylic organic material. However, the types of materials constituting the inorganic layers IOL1 and IOL2 and the organic layer OL are not limited thereto.

[0101] As in Figure 3 and Figure 4A As explained in the specification, the optical layer OSL may be disposed on the encapsulation layer TFE. The optical layer OSL may include a light control layer CCL. In an embodiment, the light control layer CCL may include quantum dots. In addition to the light control layer CCL, the optical layer OSL may further include a low refractive index layer LR, a color filter layer CFL, and a base substrate BL. In the specification, the optical layer OSL may be referred to as an upper panel.

[0102] The light control layer CCL may be disposed on the display layer DP-ED including the light emitting element OEL. The light control layer CCL may include a bank BMP and light control units CCP-R, CCP-G, and CCP-B.

[0103] The bank BMP may include a base resin and an additive. The base resin may be formed of various resin compositions that may be generally referred to as a binder. The additive may include a coupling agent and / or a photoinitiator. The additive may further include a dispersant.

[0104] The bank BMP may include a black colorant for blocking light. The bank BMP may include a black dye and / or a black pigment mixed in a base resin. In an embodiment, the black colorant may include carbon black, or may include a metal such as chromium or an oxide thereof.

[0105] The bank BMP may include a bank opening BW-OH corresponding to the light emitting opening OH. In a plan view, the bank opening BW-OH may overlap with the light emitting opening OH and may have an area larger than that of the light emitting opening OH. For example, the bank opening BW-OH may have a large area compared to the light emitting areas EA1, EA2, and EA3 defined by the light emitting opening OH. In the specification, "corresponding to" means that when viewed in the third direction DR3 which is the thickness direction of the display device DD, the two components overlap and are not limited to having the same area.

[0106] The light control units CCP-R, CCP-G, and CCP-B may be disposed inside the bank opening BW-OH. At least some of the light control units CCP-R, CCP-G, and CCP-B may change the optical properties of the source light. In an embodiment, at least some of the light control units CCP-R, CCP-G, and CCP-B may include quantum dots that change the optical properties of the source light.

[0107] In an embodiment, the first light control unit CCP-R may include quantum dots for changing the optical characteristics of the source light. The quantum dots included in the first light control unit CCP-R may convert the source light into light of a different wavelength. For example, in the first light control unit CCP-R overlapping the first pixel area PXA-R, the quantum dots may convert the source light into red light.

[0108] In the specification, quantum dots may be crystals of semiconductor compounds. Quantum dots may emit light of various wavelengths depending on the size of the crystals. By adjusting the ratio of elements in the quantum dot compound, the quantum dots may emit light of various wavelengths.

[0109] The diameter of the quantum dot may be, for example, in the range of about 1 nm to about 10 nm. The quantum dot may be synthesized by a wet chemical process, a metal organic chemical vapor deposition (MOCVD) process, a molecular beam epitaxy (MBE) process, or a process similar thereto.

[0110] In the manufacturing process of quantum dots, the wet chemical process is a method of mixing an organic solvent with a precursor material and growing quantum dot particle crystals. When the quantum dot particle crystals grow, the organic solvent naturally acts as a dispersant coordinated on the surface of the quantum dot particle crystals, and the growth of the quantum dot particle crystals can be controlled. Therefore, the wet chemical process is easier to perform than vapor deposition methods (such as metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE)) and the growth of quantum dot crystal particles can be controlled by a low-cost process.

[0111] The core of the quantum dot may include at least one of a II-VI group compound, a III-V group compound, a III-VI group compound, a I-III-VI group compound, a IV-VI group compound, a II-IV-V group compound, a Group IV element, a Group IV compound, and any combination thereof.

[0112] The II-VI Group compounds may be selected from the group consisting of: binary compounds selected from the group consisting of CdSe, CdTe, CdS, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS and mixtures thereof, and binary compounds selected from the group consisting of CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, Cd ZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS and mixtures thereof, and ternary compounds selected from the group consisting of CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe and mixtures thereof. The II-VI Group compound may further include a Group I metal and / or a Group IV element. The I-II-VI Group compound may be selected from CuSnS and CuZnS and the II-IV-VI Group compound may be selected from ZnSnS and the like. The I-II-IV-VI Group compound may be selected from a quaternary compound selected from Cu 2 ZnSnS 2 , Cu 2 ZnSnS 4 , Cu 2 ZnSnSe 4 、Ag 2 ZnSnS 2 and mixtures thereof.

[0113] Group III-VI compounds may include binary compounds (such as In 2 S3 andIn 2 Se 3 etc.), ternary compounds (such as InGaS 3 and InGaSe 3 etc.) or any combination thereof.

[0114] The I-III-VI group compounds can be selected from the following ternary compounds and quaternary compounds (such as AgInGaS 2 and CuInGaS 2 The ternary compound is selected from the group consisting of: AgInS, AgInS 2 、CuInS、CuInS 2 、AgGaS 2 、CuGaS 2 、CuGaO 2 、AgGaO 2 、AgAlO 2 and mixtures thereof.

[0115] The III-V compound may be selected from the group consisting of: a binary compound selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and mixtures thereof, a ternary compound selected from the group consisting of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InAlP, InNP, InNAs, InNSb, InPAs, InPSb, and mixtures thereof, and a quaternary compound selected from the group consisting of GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and mixtures thereof. The III-V compound may further include a Group II metal. For example, InZnP or the like can be selected as the Group III-II-V compound.

[0116] The Group IV-VI compounds may be selected from the group consisting of: binary compounds selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe and mixtures thereof, ternary compounds selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe and mixtures thereof, and quaternary compounds selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe and mixtures thereof.

[0117] Examples of Group II-IV-V compounds may be selected from ZnSnP, ZnSnP 2 、ZnSnAs 2 、ZnGeP 2 、ZnGeAs 2 、CdSnP 2 、CdGeP 2 and mixtures thereof.

[0118] The Group IV element may be selected from the group consisting of Si, Ge, and mixtures thereof. The Group IV compound may be a binary compound selected from the group consisting of SiC, SiGe, and mixtures thereof.

[0119] Each element included in a multi-element compound (such as a binary compound, a ternary compound, and a quaternary compound) may be present in the particle in a uniform concentration or a non-uniform concentration. For example, the formula representing a quantum dot indicates the type of element included in the quantum dot compound, and the ratio of the elements in the compound may vary. For example, AgInGaS 2 Can mean AgIn x Ga 1-x S 2 (0 <x<1)。

[0120] The binary, ternary or quaternary compound may be present in the particle at a uniform concentration, or may be present in the same particle at a partially different concentration distribution. The binary, ternary or quaternary compound may have a core-shell structure in which one quantum dot surrounds another quantum dot. In the core-shell structure, the binary, ternary or quaternary compound may have a concentration gradient in which the concentration of the element present in the shell decreases toward the core.

[0121] In an embodiment, the quantum dot may have the above-mentioned core-shell structure including a core having nanocrystals and a shell surrounding the core. The shell of the quantum dot may be used as a protective layer to prevent chemical denaturation of the core to maintain semiconductor properties, and / or may be used as a charging layer to impart electrophoretic properties to the quantum dot. The shell may be a single layer or a multilayer. Examples of the shell of the quantum dot may be a metal oxide or a non-metal oxide, a semiconductor compound, or any combination thereof.

[0122] For example, the metal oxide or non-metal oxide may be a binary compound (such as SiO 2 、Al 2 O 3 、TiO 2 、ZnO、MnO、Mn 2 O 3 , Mn 3 O 4 , CuO, FeO, Fe 2 O 3 , Fe 3 O 4 , CoO, Co 3 O 4 and NiO) or ternary compounds (such as MgAl 2 O 4 、CoFe 2 O 4 、NiFe 2 O 4 and CoMn 2 O 4 ), but the present disclosure is not limited thereto.

[0123] The semiconductor compound may be, for example, CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP or AlSb, etc., but the present disclosure is not limited thereto.

[0124] The quantum dot may have a half-maximum full width (FWHM) of a light emitting wavelength spectrum less than or equal to about 45 nm. For example, the quantum dot may have a half-maximum full width (FWHM) of a light emitting wavelength spectrum less than or equal to about 40 nm. For example, the quantum dot may have a half-maximum full width (FWHM) of a light emitting wavelength spectrum less than or equal to about 30 nm. Color purity or color reproducibility may be improved within the above range. Light emitted by such a quantum dot may be emitted in all directions, thereby improving a wide viewing angle.

[0125] Although the form of quantum dots is not particularly limited to the forms commonly used in the art, for example, quantum dots in the form of spherical nanoparticles, pyramidal nanoparticles, multi-arm nanoparticles or cubic nanoparticles, nanotubes, nanowires, nanofibers and nanoplates can be used.

[0126] Quantum dots can adjust the energy band gap by adjusting the size of the quantum dots or adjusting the ratio of elements in the quantum dot compound, so that light of various wavelengths can be obtained from the quantum dot light-emitting layer. Therefore, a light-emitting element that emits light of various wavelengths can be realized by using quantum dots as described above (using quantum dots of different sizes or quantum dots with different ratios of elements in the quantum dot compound). For example, the size of the quantum dots or the ratio of elements in the quantum dot compound can be selected to emit red light, green light and / or blue light. The quantum dots can be configured to emit white light by combining light of various colors.

[0127] In an embodiment, the quantum dots included in the first light control unit CCP-R overlapping the first pixel region PXA-R may emit red light. The smaller the particle size of the quantum dots, the shorter the wavelength region of the light that can be emitted. For example, in quantum dots having the same core, the particle size of quantum dots emitting green light may be smaller than the particle size of quantum dots emitting red light. In quantum dots having the same core, the particle size of quantum dots emitting blue light may be smaller than the particle size of quantum dots emitting green light. However, the present disclosure is not limited thereto, and even in quantum dots having the same core, the size of the particles may be controlled according to the material used to form the shell and the thickness of the shell, etc.

[0128] In the case where quantum dots have various luminescent colors such as blue, red, and green, quantum dots having different luminescent colors may have different core materials.

[0129] The light control units CCP-R, CCP-G, and CCP-B of the light control layer CCL may include a scatterer. The first light control unit CCP-R may include quantum dots that convert source light into red light and a scatterer that scatters the light.

[0130] The scatterers may be inorganic particles. For example, the scatterers may include TiO 2 、ZnO、Al 2 O 3 、SiO 2 and hollow silica. The scatterer may include TiO 2 、ZnO、Al 2 O 3 、SiO 2 and hollow silica, or may be selected from TiO 2 、ZnO、Al 2 O 3 、SiO 2and a mixture of two or more materials in hollow silica.

[0131] The first light control unit CCP-R may include a base resin in which quantum dots and scatterers are dispersed. The base resin may be a medium in which quantum dots and scatterers are dispersed, and may be composed of various resin compositions that may be generally referred to as binders. For example, the base resin may be an acrylic resin, a urethane resin, a silicone resin, or an epoxy resin, etc. The base resin may be a transparent resin.

[0132] In an embodiment, the first light control unit CCP-R may be formed by an inkjet printing process. A liquid ink composition may be provided inside the bank opening BW-OH, and a polymerization and curing reaction may be performed by a thermal curing process or a photocuring process to form the first light control unit CCP-R from the ink composition.

[0133] Part of the description of the first light control unit CCP-R may be equally applied to the second light control unit CCP-G and the third light control unit CCP-B.

[0134] refer to Figure 4A , the light control layer CCL may include light control units CCP-R, CCP-G, and CCP-B that are different from each other. The light control units CCP-R, CCP-G, and CCP-B may be spaced apart from each other. The light control units CCP-R, CCP-G, and CCP-B may be spaced apart from each other by the dam BMP. The light control units CCP-R, CCP-G, and CCP-B may be respectively disposed inside the dam opening BW-OH defined in the dam BMP. However, the present disclosure is not limited thereto.

[0135] exist Figure 4A In the embodiment, the bank BMP is illustrated as having a rectangular shape in the cross-sectional view and does not overlap with the light control units CCP-R, CCP-G, and CCP-B, but the edges of the light control units CCP-R, CCP-G, and CCP-B may overlap at least partially with the bank BMP. The bank BMP may have a trapezoidal shape in the cross-sectional view. The bank BMP may have a shape in the cross-sectional view in which the width increases as the bank BMP approaches the display layer DP-ED.

[0136] The second light control unit CCP-G and the third light control unit CCP-B can also be formed by an inkjet printing process. The liquid ink compositions for forming the second light control unit CCP-G and the third light control unit CCP-B can be provided inside the bank opening BW-OH, respectively, and polymerization and curing reactions can be performed by a thermal curing process or a photocuring process to form the second light control unit CCP-G and the third light control unit CCP-B from the ink compositions.

[0137] In an embodiment, the second light control unit CCP-G may include quantum dots for changing the optical characteristics of the source light. The quantum dots included in the second light control unit CCP-G may convert the source light into light of a different wavelength. For example, in the second light control unit CCP-G overlapping the second pixel area PXA-G in a plan view, the quantum dots may convert the source light into green light.

[0138] The third light control unit CCP-B overlapping the third pixel area PXA-B may not include quantum dots. However, the present disclosure is not limited thereto, and the third light control unit CCP-B may include quantum dots that convert the wavelength of a portion of the source light provided from the light emitting element OEL.

[0139] The second light control unit CCP-G and the third light control unit CCP-B may also include a scatterer. For example, in an embodiment, the first light control unit CCP-R may include a first quantum dot and a scatterer, the second light control unit CCP-G may include a second quantum dot and a scatterer, and the third light control unit CCP-B may not include a quantum dot but may include a scatterer.

[0140] Each of the second light control unit CCP-G and the third light control unit CCP-B may further include a base resin for dispersing quantum dots and scatterers. The same contents as those described with reference to the first light control unit CCP-R may be applied to the scatterers and the base resin.

[0141] The optical layer OSL may include a first barrier layer CAP1. The first barrier layer CAP1 may be used to prevent the penetration of moisture and / or oxygen (hereinafter, referred to as "moisture / oxygen") and to improve the optical properties of the optical layer OSL by adjusting the refractive index. The first barrier layer CAP1 may be disposed on the upper portion of the light control layer CCL or on the lower portion of the light control layer CCL. The first barrier layer CAP1 may be disposed on the upper surface of the light control units CCP-R, CCP-G, and CCP-B or may be disposed on the lower surface of the light control units CCP-R, CCP-G, and CCP-B to block the light control units CCP-R, CCP-G, and CCP-B from being exposed to moisture / oxygen, and in particular, to block the quantum dots included in the light control units CCP-R, CCP-G, and CCP-B from being exposed to moisture / oxygen. The first barrier layer CAP1 may also protect the light control units CCP-R, CCP-G, and CCP-B from external impacts.

[0142] In an embodiment, the first barrier layer CAP1 may be spaced apart from the display layer DP-ED, and the light control units CCP-R, CCP-G, and CCP-B may be inserted between the first barrier layer CAP1 and the display layer DP-ED. For example, the first barrier layer CAP1 may be disposed on the upper surface of the light control units CCP-R, CCP-G, and CCP-B. In an embodiment, the optical layer OSL may further include a second barrier layer CAP2 disposed between the light control layer CCL and the display layer DP-ED. In an embodiment, the first barrier layer CAP1 may cover the upper surface of the light control units CCP-R, CCP-G, and CCP-B adjacent to the low refractive index layer LR, and the second barrier layer CAP2 may cover the lower surface of the light control units CCP-R, CCP-G, and CCP-B adjacent to the display layer DP-ED. In the specification, the "upper surface" may be a surface located at the upper portion relative to the third direction DR3, and the "lower surface" may be a surface located at the lower portion relative to the third direction DR3.

[0143] The first barrier layer CAP1 and the second barrier layer CAP2 may cover not only the surfaces of the light control units CCP-R, CCP-G, CCP-B but also the surface of the bank BMP.

[0144] The first barrier layer CAP1 may cover the surface of the dike BMP and the light control units CCP-R, CCP-G and CCP-B adjacent to the low refractive index layer LR. The first barrier layer CAP1 may be disposed (e.g., directly disposed) on the lower portion of the low refractive index layer LR. The second barrier layer CAP2 may be disposed following the steps of the dike BMP and the light control units CCP-R, CCP-G and CCP-B. The second barrier layer CAP2 may be disposed (e.g., directly disposed) on the upper portion of the filling layer FML.

[0145] The first barrier layer CAP1 and the second barrier layer CAP2 may include an inorganic material. In an embodiment, the first barrier layer CAP1 may include silicon oxynitride (SiON). Both the first barrier layer CAP1 and the second barrier layer CAP2 may include silicon oxynitride. However, the present disclosure is not limited thereto, and the first barrier layer CAP1 may include silicon oxynitride, and the second barrier layer CAP2 may include silicon oxide (SiO x ).

[0146] The optical layer OSL may further include a color filter layer CFL disposed on the light control layer CCL. The color filter layer CFL may include at least one color filter CF1, CF2, or CF3. The color filter may transmit light of a specific wavelength range and block light outside the specific wavelength range. In an embodiment, the first color filter CF1 may be a red color filter, the second color filter CF2 may be a green color filter, and the third color filter CF3 may be a blue color filter.

[0147] Each of the color filters CF1, CF2, and CF3 may include a polymer photosensitive resin and a colorant. The colorant may include a pigment and / or a dye. The first color filter CF1 may include a red pigment and / or a red dye, the second color filter CF2 may include a green pigment and / or a green dye, and the third color filter CF3 may include a blue pigment and / or a blue dye. In an embodiment, the third color filter CF3 may not include a pigment and / or a dye.

[0148] Each of the first to third color filters CF1, CF2, and CF3 may be disposed corresponding to each of the first pixel area PXA-R, the second pixel area PXA-G, and the third pixel area PXA-B. Each of the first to third color filters CF1, CF2, and CF3 may overlap each of the first to third light control units CCP-R, CCP-G, and CCP-B, respectively, in a plan view.

[0149] refer to Figure 4A , corresponding to the peripheral area NPXA, the color filters CF1, CF2, and CF3 that transmit different light from each other may overlap with each other in a plan view. Corresponding to the peripheral area NPXA, the color filters CF1, CF2, and CF3 may overlap in a third direction DR3 as a thickness direction to distinguish the boundaries between the pixel areas PXA-R, PXA-G, and PXA-B. Unlike what is explained, the color filter layer CFL may include a light-blocking portion (not shown) to distinguish the boundaries between the adjacent color filters CF1, CF2, and CF3. The light-blocking portion (not shown) may be formed by a blue color filter, or may be formed by including an organic light-blocking material or an inorganic light-blocking material containing a black pigment and / or a black dye.

[0150] refer to Figure 3 and Figure 4A , the optical layer OSL may further include a low refractive index layer LR. The low refractive index layer LR may be disposed between the light control layer CCL and the color filter layer CFL. The low refractive index layer LR may be disposed on the upper portion of the light control layer CCL to block the light control units CCP-R, CCP-G, and CCP-B from being exposed to moisture / oxygen. The low refractive index layer LR may be disposed between the light control units CCP-R, CCP-G, and CCP-B and the color filters CF1, CF2, and CF3 to perform the function of an optical functional layer such as increasing light extraction efficiency or preventing reflected light from entering the light control layer CCL. The low refractive index layer LR may be a layer having a relatively low refractive index compared to adjacent layers.

[0151] The low refractive index layer LR may include at least one inorganic layer. For example, the low refractive index layer LR may include silicon nitride, aluminum nitride, zirconium nitride, titanium nitride, hafnium nitride, tantalum nitride, silicon oxide, aluminum oxide, titanium oxide, tin oxide, cerium oxide, silicon oxynitride or a thin metal film with light transmittance, etc. However, the present disclosure is not limited thereto, and the low refractive index layer LR may include an organic film. The low refractive index layer LR may have, for example, a structure in which a plurality of hollow particles are dispersed in an organic polymer resin. The low refractive index layer LR may be composed of a single layer or a plurality of layers.

[0152] In an embodiment, the display device DD may further include a base substrate BL disposed on the color filter layer CFL. The base substrate BL may be a member providing a base surface on which the color filter layer CFL, the low refractive index layer LR, the light control layer CCL, and the like are disposed. The base substrate BL may be a glass substrate, a metal substrate, a plastic substrate, and the like. However, the present disclosure is not limited thereto, and the base substrate BL may be an inorganic layer, an organic layer, or a composite material layer. Unlike what is explained, the base substrate BL may be omitted in an embodiment.

[0153] Although not illustrated, an anti-reflection layer may be provided on the base substrate BL. The anti-reflection layer may be a layer that reduces the reflectivity of external light entering from the outside. The anti-reflection layer may be a layer that selectively transmits light emitted from the display device DD. In an embodiment, the anti-reflection layer may be a single layer including a dye and / or a pigment dispersed in a base resin. The anti-reflection layer may be provided as one continuous layer that completely overlaps the first to third pixel areas PXA-R, PXA-G, and PXA-B in a plan view.

[0154] The anti-reflection layer may not include a polarization layer. Accordingly, the light that passes through the anti-reflection layer and enters the display layer DP-ED may be non-polarized light. The display layer DP-ED may receive the non-polarized light from the anti-reflection layer.

[0155] The display device DD of the embodiment may include a lower panel including a display layer DP-ED, and an upper panel (optical layer OSL) including a light control layer CCL and a color filter layer CFL, and in an embodiment, a filling layer FML may be disposed between the lower panel and the upper panel. In an embodiment, the filling layer FML may be filled between the display layer DP-ED and the optical layer OSL. The filling layer FML may be disposed (e.g., directly disposed) on the encapsulation layer TFE, and the second barrier layer CAP2 may be disposed (e.g., directly disposed) on the filling layer FML. The lower surface of the filling layer FML may contact the upper surface of the encapsulation layer TFE, and the upper surface of the filling layer FML may contact the lower surface of the second barrier layer CAP2.

[0156] The filling layer FML may be used as a buffer between the display layer DP-ED of the lower panel and the light control layer CCL of the upper panel. In an embodiment, the filling layer FML may perform a shock absorbing function, etc., and may increase the strength of the display device DD. The filling layer FML may be formed of a filling resin including a polymer resin. For example, the filling layer FML may be formed of a filling resin including an acrylic resin or an epoxy resin, etc.

[0157] refer to Figure 3 and Figure 4A The display device DD of the described embodiment may further include the light-emitting element described below. The display device DD of the embodiment may include a plurality of stacked light-emitting structures, and include a green light-emitting structure among the light-emitting structures, the green light-emitting structure including a light-emitting layer including a low-refractive index material, and therefore, may have excellent light-emitting efficiency characteristics. For example, in the light-emitting layer of at least one green light-emitting structure among the plurality of light-emitting structures included in the light-emitting stack ST, a low-refractive index material may be included in a sub-light-emitting layer adjacent to a hole transport region, and accordingly, the display device DD of the embodiment may have excellent light-emitting efficiency.

[0158] Figure 4B and Figure 4C Each is a schematic cross-sectional view showing a part of a display device according to an embodiment of the present disclosure. Figure 4B and Figure 4C The display device explained in the present invention is different from the reference in terms of the configuration of the optical layer. Figure 3 and 4A The display device described is partially different. Figure 4B and Figure 4C In the description of the display device of FIG. 1 to FIG. Figure 4A description, etc., but will explain the differences.

[0159] refer to Figure 4B According to an embodiment, the display device DD-1 may include: a lower panel including a base layer BS, a circuit layer DP-CL disposed on the base layer BS, and a display layer DP-ED disposed on the circuit layer DP-CL; and an optical layer OSL-1 disposed on the lower panel. In the display device DD-1 according to an embodiment, the optical layer OSL-1 may include a light control layer CCL-1, a low refractive index layer LR-1, a color filter layer CFL-1, and a base substrate BL-1 sequentially stacked on the encapsulation layer TFE. The optical layer OSL-1 may include a first barrier layer CAP1 disposed on the upper surface of the light control layer CCL-1 and a second barrier layer CAP2 disposed on the lower surface of the light control layer CCL-1.

[0160] and Figure 4A Compared with the display device DD explained in Figure 4BThe display device DD-1 illustrated in the embodiment is an embodiment in which the optical layer OSL-1 is provided by using the upper surface of the encapsulation layer TFE as the substrate surface. For example, the light control units CCP-R, CCP-G and CCP-B of the light control layer CCL-1 can be formed on the encapsulation layer TFE by a continuous process, and the color filters CF1, CF2 and CF3 of the color filter layer CFL-1 can be sequentially formed on the light control layer CCL-1 by a continuous process. Figure 4A Compared to the implementation described in Figure 4B In the display device DD-1 explained in the embodiment, the filling layer FML can be omitted (see Figure 4A ).

[0161] In an embodiment, the light control layer CCL-1 may have an upper surface of the second barrier layer CAP2 disposed on the encapsulation layer TFE as a base surface, and thus, may have a Figure 4A Specifically, each of the plurality of banks BMP and the plurality of light control units CCP-R, CCP-G, and CCP-B may have a shape similar to that of the light control layer CCL. Figure 4A The color filter layer CFL-1 may have an upper surface of the light control layer CCL-1 as a base surface, and may have the same Figure 4A The shapes of the embodiments illustrated in the drawings are different shapes.

[0162] The color filter layer CFL-1 may include color filters CF1, CF2, and CF3 and a light blocking portion BM. In the color filter layer CFL-1 of the embodiment, the light blocking portion BM may be a black matrix. The light blocking portion BM may include an organic light blocking material or an inorganic light blocking material containing a black pigment and / or a black dye. The light blocking portion BM may prevent a light leakage phenomenon and may distinguish a boundary between adjacent color filters CF1, CF2, and CF3.

[0163] Figure 4C The display device DD-2 according to the embodiment explained in Figure 4A The display device DD illustrated in FIG. 1 is different in that a fourth pixel area PXA-W is further included in addition to the first to third pixel areas PXA-R, PXA-G, and PXA-B. The fourth pixel area PXA-W may be a white pixel area that emits white light.

[0164] exist Figure 4C In the display device DD-2 illustrated in FIG. 1 , the light emitting element OEL may generate white light, and the fourth pixel area PXA-W may be an area in which light generated in the light emitting element OEL is not converted but transmitted. Figure 4CIt is explained that the pixel areas PXA-R, PXA-G, PXA-G and PXA-W have the same width in one direction, but the present disclosure is not limited thereto, and the fourth pixel area PXA-W may have a size different from that of each of the other pixel areas PXA-R, PXA-B and PXA-G. For example, in a plan view, the area of ​​the fourth pixel area PXA-W may be different from that of each of the first to third pixel areas PXA-R, PXA-G and PXA-B. The white light emitted from the fourth pixel area PXA-W may be a mixture of light of various wavelengths. The display layer DP-ED may include a fourth light emitting area EA4 corresponding to the fourth pixel area PXA-W.

[0165] In addition to the first light control unit CCP-R, the second light control unit CCP-G and the third light control unit CCP-B, the light control layer CCL-2 of the optical layer OSL-2 of the display device DD-2 according to the embodiment may further include a fourth light control unit CCP-T. The fourth light control unit CCP-T may overlap with the fourth pixel area PXA-W in a plan view. A dam BMP may be provided between the fourth light control unit CCP-T and another adjacent light control unit. The fourth light control unit CCP-T may not include a light emitting body (such as quantum dots). The fourth light control unit CCP-T may be a transmission unit configured to transmit incident light without converting its wavelength. The fourth light control unit CCP-T may include a base resin and a scatterer dispersed in the base resin. Figure 4C The base resin and scatterer of the embodiment can be applied with reference to Figure 3 and Figure 4A The contents of the base resin and the diffuser are the same as described.

[0166] In the color filter layer CFL-2 of the optical layer OSL-2 of the display device DD-2 according to the embodiment, an opening T-OP overlapping the fourth pixel area PXA-W in a plan view may be defined. At least a portion of the fourth pixel area PXA-W may not overlap the color filters CF1, CF2, and CF3 and the light blocking portion BM included in the color filter layer CFL-2 in a plan view. The color filters CF1, CF2, and CF3 and the light blocking portion BM included in the color filter layer CFL-2 may not overlap the fourth light emitting area EA4 in a plan view.

[0167] For example, in an embodiment, the opening T-OP corresponding to the fourth pixel region PXA-W may be defined in the third color filter CF3 of the color filter layer CFL-2, and accordingly, the color filters CF1, CF2, and CF3 and the light blocking portion BM may not overlap with the fourth pixel region PXA-W. However, the present disclosure is not limited thereto, and the third color filter CF3 may overlap with the fourth pixel region PXA-W, and the third color filter CF3 may be formed of a transparent photosensitive resin.

[0168] Figure 4B and Figure 4C Each of the display device DD-1 and the display device DD-2 according to the embodiment explained in the embodiment may include a light-emitting element OEL including a light-emitting stack ST, and may include a low-refractive-index material in a light-emitting layer in at least one green light-emitting structure among a plurality of light-emitting structures included in the light-emitting stack ST. For example, in the light-emitting layer of at least one green light-emitting structure among a plurality of light-emitting structures included in the light-emitting stack ST, a low-refractive-index material may be included in a sub-light-emitting layer adjacent to a hole transport region, and accordingly, the display device DD-1 and the display device DD-2 of the embodiment may exhibit excellent light-emitting efficiency.

[0169] In the following, reference Figures 5 to 9 etc., the light emitting element of the embodiment will be described.

[0170] Figure 5 Schematic cross-sectional view schematically showing a light emitting element according to an embodiment of the present disclosure. Fig. 6A and Figure 6B Each is a schematic cross-sectional view showing an embodiment of a light emitting structure that emits green light among light emitting structures included in a light emitting element. Fig. 7A and Figure 7B Each is a schematic cross-sectional view showing an embodiment of a light emitting structure that emits blue light among light emitting structures included in a light emitting element.

[0171] The light emitting element OEL of the embodiment may include a first electrode EL1, a second electrode EL2 facing the first electrode EL1, and a plurality of light emitting structures EU-1, EU-2, EU-3, and EU-4 disposed between the first electrode EL1 and the second electrode EL2. For example, the light emitting element OEL of the embodiment may include three or more light emitting structures disposed between the first electrode EL1 and the second electrode EL2.

[0172] The light emitting element OEL of the embodiment may include a blue light emitting structure emitting blue light and a green light emitting structure emitting green light. The light emitting element OEL of the embodiment may include a plurality of blue light emitting structures EU-B and / or a plurality of blue light emitting structures EU-Ba and at least one green light emitting structure EU-G and / or at least one green light emitting structure EU-Ga.

[0173] refer to Figure 5, the light emitting element OEL of the embodiment may include a first light emitting structure EU-1, a second light emitting structure EU-2, a third light emitting structure EU-3, and a fourth light emitting structure EU-4 stacked in sequence. For example, in the embodiment, the first light emitting structure EU-1, the second light emitting structure EU-2, and the third light emitting structure EU-3 may be a blue light emitting structure emitting blue light, and the fourth light emitting structure EU-4 may be a green light emitting structure. However, the present disclosure is not limited thereto, and the position of the green light emitting structure included in the light emitting element OEL and the number of green light emitting structures may vary.

[0174] exist Figure 5 In the embodiment illustrated in FIG. 1 , light generated in the light emitting element OEL may be emitted in a direction of an upper surface of the second electrode EL2 (ie, in the third direction DR3 ).

[0175] The light emitting element OEL according to the embodiment may include charge generation layers CGL-1, CGL-2 and CGL-3 disposed between the light emitting structures EU-1, EU-2, EU-3 and EU-4. The light emitting element OEL according to the embodiment may include a first charge generation layer CGL-1 disposed between the first light emitting structure EU-1 and the second light emitting structure EU-2, a second charge generation layer CGL-2 disposed between the second light emitting structure EU-2 and the third light emitting structure EU-3, and a third charge generation layer CGL-3 disposed between the third light emitting structure EU-3 and the fourth light emitting structure EU-4.

[0176] When a voltage is applied to the light-emitting element OEL, the charge generation layers CGL-1, CGL-2, and CGL-3 may generate charges (electrons and holes) by forming a complex using a redox reaction. The charge generation layers CGL-1, CGL-2, and CGL-3 may provide the generated charges to each of the adjacent light-emitting structures EU-1, EU-2, EU-3, and EU-4. The charge generation layers CGL-1, CGL-2, and CGL-3 may increase the efficiency of the current generated in each of the light-emitting structures EU-1, EU-2, EU-3, and EU-4, and may be used to control the balance of charges between the adjacent light-emitting structures EU-1, EU-2, EU-3, and EU-4.

[0177] Each of the charge generation layers CGL-1, CGL-2, and CGL-3 may have a layered structure in which an n-type charge generation layer n-CGL and a p-type charge generation layer p-CGL are combined with each other.

[0178] The n-type charge generation layer n-CGL may be a charge generation layer that provides electrons to the adjacent light emitting structures EU-1, EU-2, EU-3 and EU-4. The n-type charge generation layer n-CGL may be a layer in which a base material is doped with an n-type dopant. The p-type charge generation layer p-CGL may be a charge generation layer that provides holes to the adjacent light emitting structures EU-1, EU-2, EU-3 and EU-4. The p-type charge generation layer p-CGL may be a layer in which a base material is doped with a p-type dopant.

[0179] Although not illustrated, a buffer layer may be further disposed between the n-type charge generation layer n-CGL and the p-type charge generation layer p-CGL.

[0180] Each of the charge generation layers CGL-1, CGL-2 and CGL-3 may include an n-type aromatic amine material or a p-type metal derivative. For example, each of the charge generation layers CGL-1, CGL-2 and CGL-3 may include an aromatic amine organic compound, a metal, a metal oxide, a metal carbide, a metal fluoride or a mixture thereof.

[0181] For example, the aromatic amine organic compound may be N'-bis(naphthalene-1-yl)-N,N'-di(phenyl)-2,2'-dimethylbenzidine (α-NPD), 2-TNATA, TDATA, MTDATA, 2,2',7,7'-tetrakis(N,N-diphenylamino)-2,7-diamino-9,9-spirobifluorene (spiro-TAD) or N,N'-bis(naphthalene-1-yl)-N,N'-di(phenyl)-2,7-diamino-9,9-spirobifluorene (spiro-NPB). For example, the metal may be cesium (Cs), molybdenum (Mo), vanadium (V), titanium (Ti), tungsten (W), barium (Ba) or lithium (Li). For example, the metal oxide, metal carbide and metal fluoride may be Re 2 O 7 、MoO 3 、V 2 O 5 , WO 3 、TiO 2 , Cs 2 CO 3 , BaF 2 , LiF or CsF.

[0182] In the light emitting element OEL according to the embodiment, the first electrode EL1 may be a reflective electrode. For example, the first electrode EL1 may include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF, Mo, Ti, W, In, Zn, Sn or a compound or mixture thereof (e.g., a mixture of Ag and Mg) having high reflectivity, or a material having a multilayer structure such as LiF / Ca or LiF / Al. According to the embodiment, the first electrode EL1 may have a multilayer structure including a reflective layer formed of one of the above materials and a transparent conductive layer formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO) or indium tin zinc oxide (ITZO), etc. For example, the first electrode EL1 may have a two-layer structure of ITO / Ag or a three-layer structure of ITO / Ag / ITO, but the present disclosure is not limited thereto. The first electrode EL1 may include one of the above metal materials, a combination of two or more of the above metal materials, or an oxide of one of the above metal materials, etc. The thickness of the first electrode EL1 may be in the range of about 70 nm to about 1000 nm. For example, the thickness of the first electrode EL1 may be in the range of about 100 nm to about 300 nm.

[0183] In the light emitting element OEL according to the embodiment, the second electrode EL2 may be a transflective electrode, a transmissive electrode or a reflective electrode. When the second electrode EL2 is a transmissive electrode, the second electrode EL2 may be formed of a transparent metal oxide (e.g., indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO) or indium tin zinc oxide (ITZO)).

[0184] In the case where the second electrode EL2 is a transflective electrode or a reflective electrode, the second electrode EL2 may include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF, Mo, Ti, Yb, W, In, Zn, Sn, or a compound or mixture thereof (e.g., AgMg, AgYb, or MgYb), or a material having a multilayer structure such as LiF / Ca or LiF / Al. According to an embodiment, the second electrode EL2 may be a multilayer structure including a reflective layer or a transflective layer (both formed of the above materials) and a transparent conductive layer formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or indium tin zinc oxide (ITZO), etc. For example, the second electrode EL2 may include one of the above metal materials, a combination of two or more of the above metal materials, or an oxide of one of the above metal materials, etc.

[0185] Although not illustrated, the second electrode EL2 may be connected to the auxiliary electrode. In the case where the second electrode EL2 is connected to the auxiliary electrode, the resistance of the second electrode EL2 may be reduced.

[0186] On the second electrode EL2 of the light emitting element OEL of the embodiment, a capping layer CPL may be further provided. The capping layer CPL may include a plurality of layers or a single layer.

[0187] 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 capping layer CPL may include an alkali metal compound (such as LiF), an alkaline earth metal compound (such as MgF 2 )、SiON、SiN X or SiO y wait.

[0188] For example, in the case where the capping layer CPL may include an organic material, the organic material may include α-NPD, NPB, TPD, m-MTDATA, Alq 3 , CuPc, N4,N4,N4',N4'-tetrakis(biphenyl-4-yl)biphenyl-4,4'-diamine (TPD15) or 4,4',4"-tris(carbazole-9-yl)triphenylamine (TCTA), etc., or may include epoxy resin or acrylate (such as methacrylate). However, the present disclosure is not limited thereto, and the capping layer CPL may include at least one of the following compounds P1 to P5.

[0189]

[0190] The refractive index of the capping layer CPL may be greater than or equal to about 1.6. For example, for light having a wavelength region within a range of about 550 nm to about 660 nm, the refractive index of the capping layer CPL may be greater than or equal to about 1.6.

[0191] The light-emitting structures EU-1, EU-2, EU-3, and EU-4 may include light-emitting layers EML-1, EML-2, EML-3, and EML-4, respectively. The light-emitting structures EU-1, EU-2, EU-3, and EU-4 may include stacked hole transport regions HTR-1, HTR-2, HTR-3, and HTR-4, light-emitting layers EML-1, EML-2, EML-3, and EML-4, and electron transport regions ETR-1, ETR-2, ETR-3, and ETR-4, respectively. For example, the light-emitting element OEL of the embodiment may be a light-emitting element of a series structure including a plurality of light-emitting layers stacked in the third direction DR3.

[0192] The hole transport regions HTR-1, HTR-2, HTR-3 and HTR-4 respectively included in the light-emitting structures EU-1, EU-2, EU-3 and EU-4 may have: a single-layer structure having a single layer formed of a single material; a single-layer structure having a single layer formed of different materials; or a multi-layer structure having a plurality of layers formed of a plurality of different materials.

[0193] The hole transport regions HTR-1, HTR-2, HTR-3 and HTR-4 may each be formed by using various methods such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB), inkjet printing, laser printing, and laser induced thermal imaging (LITI).

[0194] The hole transport regions HTR-1, HTR-2, HTR-3, and HTR-4 may each include a hole transport material. For example, the hole transport regions HTR-1, HTR-2, HTR-3, and HTR-4 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"-[tri(3-methylphenyl)phenylamino]triphenylamine (m-MTDATA), 4,4',4"-tri(N,N-diphenylamino)triphenylamine (TDATA), 4,4',4"-tri[N-(1-naphthyl)-N-phenylamino]triphenylamine (1-TNATA), 4,4',4"-tri[N-(2-naphthyl)-N-phenylamino]triphenylamine (2-TNATA), poly(3,4-ethylenedioxydioxythiophene) / poly(4-styrenesulfonate) (PEDOT / P SS), polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), polyaniline / camphorsulfonic acid (PANI / CSA), polyaniline / poly(4-styrenesulfonate) (PANI / PSS), N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPB) (or NPD), triphenylamine-containing polyetherketone (TPAPEK), 4-isopropyl-4'-methyldiphenyliodonium [tetrakis(pentafluorophenyl)borate] or dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN), etc.

[0195] The hole transport regions HTR-1, HTR-2, HTR-3 and HTR-4 may include carbazole derivatives (such as N-phenylcarbazole and polyvinylcarbazole), fluorene derivatives or triphenylamine derivatives (such as 4,4',4"-tri(carbazole-9-yl)triphenylamine (TCTA), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD), N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPB), 4,4'-cyclohexylenebis[N,N-bis(4-methylphenyl)aniline] (TAPC), 4,4'-bis[N,N'-(3-tolyl)amino]-3,3'-dimethylbiphenyl (HMTPD) or 1,3-bis(N-carbazolyl)benzene (mCP)), etc.

[0196] The hole transport regions HTR-1, HTR-2, HTR-3 and HTR-4 may include 9-(4-tert-butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole (CzSi), 9-phenyl-9H-3,9'-bicarbazole (CCP) or 1,3-bis(1,8-dimethyl-9H-carbazole-9-yl)benzene (mDCP) or the like.

[0197] In addition to the materials mentioned above, the hole transport regions HTR-1, HTR-2, HTR-3, and HTR-4 may further include a charge generation material to improve conductivity. The charge generation material may be uniformly or non-uniformly dispersed in the hole transport regions HTR-1, HTR-2, HTR-3, and HTR-4. The charge generation material may be, for example, a p-type dopant. The p-type dopant may include at least one of a metal halide, a quinone derivative, a metal oxide, and a cyano-containing compound, but the present disclosure is not limited thereto. For example, the p-type dopant may be a metal halide (such as CuI and RbI), a quinone derivative (such as tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanoquinodimethane (F4-TCNQ)), a metal oxide (such as tungsten oxide and molybdenum oxide) and a cyano compound (such as dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN) and 4-[[2,3-bis[cyano-(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropylidene]-cyanomethyl]-2,3,5,6-tetrafluorobenzonitrile (NDP9)), etc., but the present disclosure is not limited thereto.

[0198] Fig. 6A and Figure 6B Embodiments of the green light emitting structure EU-G and the green light emitting structure EU-Ga among the light emitting structures included in the light emitting element OEL are schematically explained. Fig. 7A and Figure 7BEmbodiments of the blue light emitting structure EU-B and the blue light emitting structure EU-Ba among the light emitting structures included in the light emitting element OEL are schematically explained.

[0199] In an embodiment, Figure 5 The fourth light emitting structure EU-4 in the light emitting element OEL may include Fig. 6A and Figure 6B The green light-emitting structure EU-G and the green light-emitting structure EU-Ga explained in . Figure 5 The first to third light emitting structures EU-1, EU-2 and EU-3 in the light emitting element OEL may include Fig. 7A and Figure 7B In an embodiment, the green light emitting structure EU-G and the green light emitting structure EU-Ga may emit green light having a light emitting center wavelength in the range of about 520nm to about 600nm. In an embodiment, the blue light emitting structure EU-B and the blue light emitting structure EU-Ba may emit blue light having a light emitting center wavelength in the range of about 430nm to about 470nm.

[0200] refer to FIG. 6A to FIG. 7B , the hole transport region HTR and the hole transport region HTR-a may include a hole injection layer HIL and a hole transport layer HTL. The hole transport region HTR may include at least one of a hole injection layer HIL, a hole transport layer HTL, a buffer layer (not shown), a light-emitting auxiliary layer (not shown), and an electron blocking layer (not shown). In an embodiment, the hole transport region HTR and the hole transport region HTR-a may have a single-layer structure having a single layer formed of different materials, or a structure having a hole injection layer HIL / hole transport layer HTL, a hole injection layer HIL / hole transport layer HTL / buffer layer (not shown), a hole injection layer HIL / buffer layer (not shown), or a hole transport layer HTL / buffer layer (not shown) stacked in sequence, but the present disclosure is not limited thereto.

[0201] For example, the hole transport region HTR and the hole transport region HTR-a may include a plurality of stacked hole transport layers. In the case where the hole transport region HTR includes a plurality of hole transport layers, one of the plurality of hole transport layers may include a low refractive index hole transport material. The low refractive index hole transport material may have a relatively low refractive index at the same wavelength as the hole transport material included in another adjacent hole transport layer.

[0202] exist Figure 5In the light-emitting element OEL of the embodiment illustrated in , the light-emitting layers EML-1, EML-2, EML-3 and EML-4 are respectively disposed on the hole transport regions HTR-1, HTR-2, HTR-3 and HTR-4. The light-emitting layers EML-1, EML-2, EML-3 and EML-4 may each have, for example, about to about The thickness is within the range of about to about The light-emitting layers EML-1, EML-2, EML-3 and EML-4 may have a single-layer structure having a single layer formed of a single material; a single-layer structure having a single layer formed of different materials; or a multi-layer structure having a plurality of layers formed of a plurality of different materials. The light-emitting layers EML-1, EML-2, EML-3 and EML-4 may include a fluorescent emission material or a phosphorescent light-emitting material. The light-emitting layers EML-1, EML-2, EML-3 and EML-4 may include a host material. In an embodiment, at least one of the light-emitting layers EML-1, EML-2, EML-3 and EML-4 may include both a hole transport host and an electron transport host.

[0203] In the light-emitting element OEL of the embodiment, the light-emitting layers EML-1, EML-2, EML-3 and EML-4 may include anthracene derivatives, pyrene derivatives, fluoranthene derivatives, 1,2-benzophenanthrene derivatives, dihydrobenzanthracene derivatives or triphenylene derivatives, etc. For example, the light-emitting layer EML may include anthracene derivatives or pyrene derivatives. However, the present disclosure is not limited thereto, and the light-emitting layer EML may include another light-emitting material.

[0204] In the light emitting element OEL of the embodiment, the plurality of light emitting layers EML-1, EML-2, EML-3 and EML-4 of the first to fourth light emitting structures EU-1, EU-2, EU-3 and EU-4 may include a blue light emitting layer emitting blue light. For example, in the embodiment, the light emitting layer EML-1 of the first light emitting structure EU-1, the light emitting layer EML-2 of the second light emitting structure EU-2 and the light emitting layer EML-3 of the third light emitting structure EU-3 may be a blue light emitting layer. In the light emitting element OEL of the embodiment, the light emitting layer EML-4 of the fourth light emitting structure EU-4 may be a green light emitting layer emitting green light.

[0205] In the light-emitting element OEL of the embodiment, at least one of the light-emitting layers EML-1, EML-2, EML-3, and EML-4 of the light-emitting structures EU-1, EU-2, EU-3, and EU-4 may include a plurality of sub-light-emitting layers. For example, the fourth light-emitting layer EML-4 may have a double-layer structure. At least one of the first to third light-emitting layers EML-1, EML-2, and EML-3 may have a double-layer structure.

[0206] Fig. 6A and Figure 6B Explanation is given of embodiments of the green light emitting structure EU-G and the green light emitting structure EU-Ga among the light emitting structures included in the light emitting element OEL. Fig. 7A and Figure 7B Embodiments of the blue light emitting structure EU-B and the blue light emitting structure EU-Ba among the light emitting structures included in the light emitting element OEL are explained.

[0207] refer to Fig. 6A and Figure 6B The green light emitting structure EU-G and the green light emitting structure EU-Ga may include two stacked sub-light emitting layers EML-GB and EML-GT. The green light emitting structure EU-G and the green light emitting structure EU-Ga may include a first sub-light emitting layer EML-GB including a low refractive index material and a second sub-light emitting layer EML-GT not including a low refractive index material.

[0208] The low refractive index material included in the first sub-light emitting layer EML-GB may have a refractive index value less than or equal to about 1.7 at a wavelength of 460 nm. The low refractive index material included in the first sub-light emitting layer EML-GB may be a host material. In an embodiment, the low refractive index material included in the first sub-light emitting layer EML-GB may be a hole transport host.

[0209] In addition to the low refractive index material, the first sub-light emitting layer EML-GB may further include a host and a dopant. In addition to the low refractive index material, the first sub-light emitting layer EML-GB may further include a hole transporting first host, an electron transporting second host, and a green light emitting dopant.

[0210] For example, the low refractive index material included in the first sub-light emitting layer EML-GB may be an amine compound or a nitrogen-containing compound. However, the present disclosure is not limited thereto, and the low refractive index material included in the first sub-light emitting layer EML-GB may have a refractive index value less than or equal to about 1.7 at a wavelength of 460 nm, and may be applied without limitation as long as it can be used as a host material of the light emitting layer.

[0211] The first sub-light emitting layer EML-GB may include the low-refractive index material of the following compound group 1. However, the present disclosure is not limited thereto.

[0212] [Compound Group 1]

[0213]

[0214]

[0215]

[0216] The first sub-light emitting layer EML-GB including a low refractive index material may be disposed (eg, directly disposed) on the hole transport region HTR. In the case where the hole transport region HTR includes a hole injection layer HIL and a hole transport layer HTL, the first sub-light emitting layer EML-GB may be disposed (eg, directly disposed) on the hole transport layer HTL.

[0217] The second sub-light-emitting layer EML-GT may include a host and a dopant. The second sub-light-emitting layer EML-GT may not include a low refractive index material. The second sub-light-emitting layer EML-GT may be disposed on the upper side of the first sub-light-emitting layer EML-GB. The second sub-light-emitting layer EML-GT may be disposed adjacent to the electron transport region ETR. For example, the second sub-light-emitting layer EML-GT may be disposed (e.g., directly disposed) on the first sub-light-emitting layer EML-GB. The second sub-light-emitting layer EML-GT may include a hole transport first host, an electron transport second host, and a green light-emitting dopant.

[0218] The first sub-light emitting layer EML-GB and the second sub-light emitting layer EML-GT may include the same host material and the same light-emitting dopant material. However, the present disclosure is not limited thereto, and the first sub-light emitting layer EML-GB and the second sub-light emitting layer EML-GT may include different host materials or different light-emitting dopant materials.

[0219] In an embodiment, a material containing a carbazole derivative portion and / or an amine derivative portion may be included as a hole transporting first host. In an embodiment, a material containing a nitrogen-containing aromatic ring structure (such as a pyridine derivative portion, a pyridazine derivative portion, a pyrimidine derivative portion, a pyrazine derivative portion and / or a triazine derivative portion, etc.) may be included as an electron transporting second host.

[0220] In the light-emitting element OEL according to the embodiment, the hole transport first host included in the light-emitting layer EML-G of the green light-emitting structure EU-G (hereinafter, also referred to as "green light-emitting layer EML-G") and the light-emitting layer EML-Ga of the green light-emitting structure EU-Ga (hereinafter, also referred to as "green light-emitting layer EML-Ga") may include one of the materials H4-1 to H4-12 listed below. However, the hole transport first host material included in the light-emitting layer EML-G is not limited to the following compounds.

[0221]

[0222] In the light-emitting element OEL according to the embodiment, the electron transport second host included in the light-emitting layer EML-G of the green light-emitting structure EU-G and the light-emitting layer EML-Ga of the green light-emitting structure EU-Ga may include one of the materials H3-1 to H3-23 listed below. However, the electron transport second host material included in the light-emitting layer EML-G and the light-emitting layer EML-Ga is not limited to the following compounds.

[0223]

[0224]

[0225] In the light-emitting element OEL according to the embodiment, the light-emitting dopant included in the light-emitting layer EML-G of the green light-emitting structure EU-G and the light-emitting layer EML-Ga of the green light-emitting structure EU-Ga may be a phosphorescent dopant. For example, the light-emitting dopant included in the light-emitting layer EML-G of the green light-emitting structure EU-G and the light-emitting layer EML-Ga of the green light-emitting structure EU-Ga may be an organic metal complex. However, the present disclosure is not limited thereto. The first sub-light-emitting layer EML-GB and the second sub-light-emitting layer EML-GT may include the same light-emitting dopant or different light-emitting dopants.

[0226] In the light emitting element OEL according to the embodiment, the light emitting dopant included in the green light emitting layer EML-G of the green light emitting structure EU-G and the green light emitting layer EML-Ga of the green light emitting structure EU-Ga may include one of the materials PD1 to PD25 listed below. However, the light emitting dopant included in the light emitting layer EML-G of the green light emitting structure EU-G and the light emitting layer EML-Ga of the green light emitting structure EU-Ga is not limited to the following compounds.

[0227]

[0228]

[0229] For example, in an embodiment, the hole transporting first host and the electron transporting second host may have the following structures, respectively.

[0230] <Hole-Transporting First Host (ie, H4-12 above)>

[0231]

[0232] <Electron Transport Second Host (ie, H3-23 above)>

[0233]

[0234] The green light-emitting dopant of each of the first sub-light-emitting layer EML-GB and the second sub-light-emitting layer EML-GT may be a phosphorescent light-emitting dopant. For example, in an embodiment, the first sub-light-emitting layer EML-GB and the second sub-light-emitting layer EML-GT may include a green light-emitting dopant having the following structure (ie, corresponding to the above-mentioned PD13).

[0235]

[0236] The thickness ratio of the first sub-light emitting layer EML-GB and the second sub-light emitting layer EML-GT can be adjusted according to the light emitting characteristics required in the light emitting structure. For example, the first sub-light emitting layer EML-GB and the second sub-light emitting layer EML-GT can have the same thickness. The meaning of the same thickness corresponds to within the range including process errors.

[0237] However, the present disclosure is not limited thereto, and the thickness of the first sub-light-emitting layer EML-GB and the thickness of the second sub-light-emitting layer EML-GT in the light-emitting layer EML-G and the light-emitting layer EML-Ga may be different from each other. For example, the thickness ratio of the first sub-light-emitting layer EML-GB and the second sub-light-emitting layer EML-GT in the light-emitting layer EML-G and the light-emitting layer EML-Ga may be in the range of about 7:3 to about 3:7.

[0238] and Fig. 6A Compared with the green light emitting structure EU-G according to the embodiment explained in Figure 6B The green light emitting structure EU-Ga according to the embodiment explained in FIG. 2 is different in the configuration of the hole transport region.

[0239] Figure 6B The green light emitting structure EU-Ga according to the embodiment explained in the figure may further include an auxiliary hole transport layer HTL-L containing a low refractive index hole transport material. The hole transport region HTR-a may include the auxiliary hole transport layer HTL-L, and the auxiliary hole transport layer HTL-L may be disposed adjacent to the upper surface of the hole transport layer HTL. In an embodiment, the hole transport region HTR-a of the green light emitting structure EU-Ga may include a hole injection layer HIL, a hole transport layer HTL, and an auxiliary hole transport layer HTL-L stacked in sequence.

[0240] In an embodiment, the auxiliary hole transport layer HTL-L may be a hole transport layer disposed adjacent to the light emitting layer EML-Ga. The auxiliary hole transport layer HTL-L may include a low refractive index hole transport material having a refractive index value less than or equal to about 1.7 at a wavelength of 460 nm.

[0241] In an embodiment, the first sub-light emitting layer EML-GB may be disposed (e.g., directly disposed) on the auxiliary hole transport layer HTL-L. The second sub-light emitting layer EML-GT may be spaced apart from the auxiliary hole transport layer HTL-L, and the first sub-light emitting layer EML-GB may be inserted between the second sub-light emitting layer EML-GT and the auxiliary hole transport layer HTL-L.

[0242] For example, the low refractive index hole transport material included in the auxiliary hole transport layer HTL-L may be an amine compound. However, the present disclosure is not limited thereto, and the low refractive index hole transport material included in the auxiliary hole transport layer HTL-L may have a refractive index value of less than or equal to about 1.7 at a wavelength of 460 nm, and may be applied without limitation as long as it is a material having hole transport properties.

[0243] In an embodiment, the low refractive index material included in the first sub-light emitting layer EML-GB and the low refractive index hole transport material included in the auxiliary hole transport layer HTL-L may be the same However, the present disclosure is not limited thereto.

[0244] For example, the auxiliary hole transport layer HTL-L may include the following compound (ie, Compound 1 in the above-mentioned Compound Group 1) as a low-refractive-index hole transport material.

[0245]

[0246] In addition, the auxiliary hole transport layer HTL-L may include other compounds in the above-mentioned compound group 1 as a low-refractive-index hole transport material.

[0247] According to reference Fig. 6A and Figure 6B The green light emitting structure EU-G and the green light emitting structure EU-Ga of the described embodiment include a low refractive index material in the first sub-light emitting layer EML-GB spaced apart from the electron transport region ETR, and therefore, can have increased light extraction efficiency without deteriorating electrical characteristics in the light emitting layer EML-G and the light emitting layer EML-Ga. The light emitting layer EML-G of the green light emitting structure EU-G and the light emitting layer EML-Ga of the green light emitting structure EU-Ga may be referred to as a green light emitting layer.

[0248] The light emitting element OEL including the green light emitting structure EU-G and / or the green light emitting structure EU-Ga according to the embodiment may have excellent light emitting efficiency. For example, the green light emitting layer EML-G and the green light emitting structure EU-Ga including the low refractive index material in the first sub-light emitting layer EML-GB are formed in the light emitting stack ST (see Figure 3 ) can be arranged relatively close to the light extraction surface, so that the light emitting element OEL can have excellent light emitting efficiency.

[0249] exist Fig. 7A and Figure 7B In the present invention, a blue light emitting structure EU-B and a blue light emitting structure EU-Ba respectively including a blue light emitting layer EML-B (hereinafter, also referred to as “light emitting layer EML-B”) and a blue light emitting layer EML-Ba (hereinafter, also referred to as “light emitting layer EML-Ba”) are explained. Fig. 7A In the embodiment, a blue light emitting structure EU-B is explained in which a light emitting layer EML-B is provided. Figure 7B , an embodiment in which the light-emitting layer EML-Ba of the blue light-emitting structure EU-Ba includes two sub-light-emitting layers EML-BB and EML-BT is explained.

[0250] The blue light emitting layer EML-B and the blue light emitting layer EML-Ba may each include a host and a blue light emitting dopant. The blue light emitting dopant may be a fluorescent dopant. However, the present disclosure is not limited thereto.

[0251] exist Figure 7B In an embodiment, the blue light-emitting layer EML-Ba may include both a hole transport host and an electron transport host. In addition to the blue light-emitting dopant as a fluorescent dopant, the blue light-emitting layer EML-B and the blue light-emitting layer EML-Ba may further include a phosphorescent sensitizer, etc. The blue light-emitting layer EML-B and the blue light-emitting layer EML-Ba may not include a low refractive index material.

[0252] In the case where the light-emitting layer EML-Ba includes two sub-light-emitting layers EML-BB and EML-BT, the material composition of the lower sub-light-emitting layer EML-BB and the material composition of the upper sub-light-emitting layer EML-BT may be the same, or at least one of the material compositions may be different from the material composition of the remaining sub-light-emitting layers.

[0253] The light-emitting layer EML-B of the blue light-emitting structure EU-B and the light-emitting layer EML-Ba of the blue light-emitting structure EU-Ba may include a host and a dopant. In an embodiment, the light-emitting layer EML-B of the blue light-emitting structure EU-B and the light-emitting layer EML-Ba of the blue light-emitting structure EU-Ba may include a host and a blue dopant. The host included in each of the light-emitting layer EML-B of the blue light-emitting structure EU-B and the light-emitting layer EML-Ba of the blue light-emitting structure EU-Ba may be a blue fluorescent host, and the dopant may be a blue fluorescent dopant.

[0254] In the light emitting element OEL according to the embodiment, the host included in each of the light emitting layer EML-B of the blue light emitting structure EU-B and the light emitting layer EML-Ba of the blue light emitting structure EU-Ba may include one of the materials H1-1 to H1-18 listed below. However, the host material included in the light emitting layer EML-B of the blue light emitting structure EU-B and the light emitting layer EML-Ba of the blue light emitting structure EU-Ba is not limited to the following compounds.

[0255]

[0256]

[0257] In an embodiment, the above compounds H1-1 to H1-18 may each independently replace any one of the hydrogen atoms with a deuterium atom. For example, the above H1-1 may be represented as the following H1-1D.

[0258]

[0259] In the light emitting element OEL according to the embodiment, the light emitting dopant included in the light emitting layer EML-B of the blue light emitting structure EU-B and the light emitting layer EML-Ba of the blue light emitting structure EU-Ba may include one of the materials FD1 to FD48 listed below. However, the dopant material included in the light emitting layer EML-B and the light emitting layer EML-Ba is not limited to the following compounds.

[0260]

[0261]

[0262]

[0263]

[0264] In addition to reference FIG. 6A to FIG. 7BIn addition to the host and dopant materials in the described light emitting structure, each of the blue light emitting layer EML-B and the blue light emitting layer EML-Ba and the green light emitting layer EML-G and the green light emitting layer EML-Ga may further include anthracene derivatives, pyrene derivatives, fluoranthene derivatives, 1,2-benzophenanthrene derivatives, dihydrobenzanthracene derivatives or triphenylene derivatives as a host material. Each of the blue light emitting layer EML-B and the blue light emitting layer EML-Ba and the green light emitting layer EML-G and the green light emitting layer EML-Ga may further include a material known in the art as a host material. For example, each of the blue light emitting layer EML-B and the blue light emitting layer EML-Ba and the green light emitting layer EML-G and the green light emitting layer EML-Ga may include, as a host material, at least one of bis[2-(diphenylphosphino)phenyl]ether oxide (DPEPO), 4,4'-bis(carbazol-9-yl)biphenyl (CBP), 1,3-bis(N-carbazolyl)benzene (mCP), 2,8-bis(diphenylphosphino)dibenzo[b,d]furan (PPF), 4,4',4"-tri(carbazol-9-yl)triphenylamine (TCTA), and 1,3,5-tri(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene (TPBi). However, the type of the host material is not limited thereto, and for example, tris(8-hydroxyquinoline)aluminum (Alq 3 ), poly(N-vinylcarbazole) (PVK), 9,10-di(naphthalene-2-yl)anthracene (ADN), 2-tert-butyl-9,10-di(naphthalene-2-yl)anthracene (TBADN), distyrylarene (DSA), 4,4'-bis(9-carbazolyl)-2,2'-dimethyl-biphenyl (CDBP), 2-methyl-9,10-bis(naphthalene-2-yl)anthracene (MADN), hexaphenylcyclotriphosphazene (CP1), 1,4-bis(triphenylsilyl)benzene (UGH2), hexaphenylcyclotrisiloxane (DPSiO 3 ) and octaphenylcyclotetrasiloxane (DPSiO 4 ) etc. can be used as the main material.

[0265] Return to reference Figure 5 , the light-emitting structures EU-1, EU-2, EU-3 and EU-4 of the light-emitting element OEL of the embodiment may include electron transport regions ETR-1, ETR-2, ETR-3 and ETR-4, respectively. The electron transport regions ETR-1, ETR-2, ETR-3 and ETR-4 respectively included in the light-emitting structures EU-1, EU-2, EU-3 and EU-4 may have: a single-layer structure having a single layer formed of a single material; a single-layer structure having a single layer formed of different materials; or a multi-layer structure having a plurality of layers formed of a plurality of different materials.

[0266] The electron transport regions ETR-1, ETR-2, ETR-3 and ETR-4 may be formed by using various methods such as vacuum deposition, spin coating, casting, Langmuir-Brokett (LB), inkjet printing, laser printing, and laser induced thermal imaging (LITI).

[0267] The electron transport regions ETR-1, ETR-2, ETR-3, and ETR-4 may include an anthracene compound. However, the present disclosure is not limited thereto, and the electron transport regions ETR-1, ETR-2, ETR-3, and ETR-4 may include tris(8-hydroxyquinoline)aluminum (Alq 3 ), 1,3,5-tris[(3-pyridyl)-phenyl-3-yl]benzene, 2,4,6-tris([1,1'-biphenyl]-3-yl)-1,3,5-triazine (T2T), 2,4,6-tris(3-(pyrimidin-5-yl)phenyl)-1,3,5-triazine (TPM-TAZ), 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-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4-(naphthalene-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole ( t Bu-PBD), bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum (BAlq), bis(benzoquinoline-10-hydroxy)beryllium (Bebq 2 ), 9,10-di(naphthalene-2-yl)anthracene (ADN), 1,3-bis[3,5-di(pyridin-3-yl)phenyl]benzene (BmPyPhB), diphenyl(4-(triphenylsilyl)phenyl)phosphine oxide (TSPO1) or a mixture thereof.

[0268] The electron transport regions ETR-1, ETR-2, ETR-3 and ETR-4 may include metal halides (such as LiF, NaCl, CsF, RbCl, RbI, CuI and KI), lanthanide metals (such as Yb) or co-deposited materials of the above metal halides and lanthanide metals. For example, the electron transport regions ETR-1, ETR-2, ETR-3 and ETR-4 may include KI:Yb, RbI:Yb or LiF:Yb as co-deposited materials. The electron transport regions ETR-1, ETR-2, ETR-3 and ETR-4 may use metal oxides (such as Li 2 O and BaO) or 8-hydroxyquinoline lithium (Liq), etc., but the present disclosure is not limited thereto. The electron transport regions ETR-1, ETR-2, ETR-3, and ETR-4 may include a mixture of an electron transport material and an insulating organic metal salt. The insulating organic metal salt may be a material having an energy band gap greater than or equal to about 4 eV. For example, the insulating organic metal salt may include a metal acetate, a metal benzoate, a metal acetoacetate, a metal acetylacetonate, or a metal stearate.

[0269] In addition to the aforementioned materials, the electron transport regions ETR-1, ETR-2, ETR-3 and ETR-4 may further include at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), diphenyl(4-(triphenylsilyl)phenyl)phosphine oxide (TSPO1) and 4,7-diphenyl-1,10-phenanthroline (Bphen), but the present disclosure is not limited thereto.

[0270] refer to FIG. 6A to FIG. 7B , the electron transport region ETR may include an electron transport layer ETL and an electron injection layer EIL. The electron transport region ETR may include at least one of an electron injection layer EIL, an electron transport layer ETL, and a hole blocking layer (not shown). In an embodiment, the electron transport region ETR may have a stacking structure of electron transport layer ETL / electron injection layer EIL, hole blocking layer (not shown) / electron transport layer ETL / electron injection layer EIL or electron transport layer ETL / buffer layer (not shown) / electron injection layer EIL, etc., but the present disclosure is not limited thereto. At least one of the electron injection layer EIL, the electron transport layer ETL, or the hole blocking layer (not shown) may include the material of the aforementioned electron transport region ETR.

[0271] exist Figure 5In the light emitting element OEL of the embodiment explained in , at least one of the light emitting structures may include a green light emitting structure EU-G and / or a green light emitting structure EU-Ga containing a low refractive index material in the first sub-light emitting layer EML-GB according to the embodiment, and due to the high light extraction efficiency in the green light emitting structure EU-G and the green light emitting structure EU-Ga, the light emitting element OEL may have excellent light emitting efficiency characteristics. Figure 5 In the light emitting element OEL of the embodiment illustrated in , there is a front emission light emitting structure in which light emitted from the light emitting structures EU-1, EU-2, EU-3, and EU-4 can be emitted to the upper portion of the second electrode EL2. Among the front emission light emitting structures, the light emitting structure EU-4 adjacent to the second electrode EL2 can be a green light emitting structure containing a low refractive index material in the light emitting layer.

[0272] When the light emitting structure EU-4 adjacent to the second electrode EL2 is a green light emitting structure, the first sub-light emitting layer EML-GB of the green light emitting structure may include a hole transport host material having a low refractive index characteristic, and the light extraction efficiency may be increased without deteriorating the electrical characteristics of the light emitting layer EML-G and the light emitting layer EML-Ga. Accordingly, the light emitting element OEL of the embodiment may have excellent light emitting efficiency characteristics.

[0273] Figure 8 and Fig. 9 Each is a schematic cross-sectional view showing a light emitting element according to an embodiment of the present disclosure. Figure 8 and Fig. 9 In the luminous stack ST (see Figure 3 ) are different from each other in terms of the number or combination of light emitting structures included. Figure 8 and Fig. 9 In the description of each composition of the light-emitting element OEL-a and the light-emitting element OEL-b explained in the above, the same components as those in the reference will not be described again. Figures 5 to 7B The content described will be the same as the content described above, but the differences will be described.

[0274] refer to Figure 8, the light emitting element OEL-a of the embodiment may include a first electrode EL1, a second electrode EL2 facing the first electrode EL1, a plurality of light emitting structures EU-1, EU-2 and EU-3 disposed between the first electrode EL1 and the second electrode EL2, and a charge generation layer CGL-1 and a charge generation layer CGL-2 disposed between the light emitting structures EU-1, EU-2 and EU-3. The first charge generation layer CGL-1 may be disposed between the first light emitting structure EU-1 and the second light emitting structure EU-2, and the second charge generation layer CGL-2 may be disposed between the second light emitting structure EU-2 and the third light emitting structure EU-3. The first charge generation layer CGL-1 and the second charge generation layer CGL-2 may each include an n-type charge generation layer n-CGL and a p-type charge generation layer p-CGL. The light emitting element OEL-a may include a capping layer CPL disposed on the second electrode EL2.

[0275] One of the light-emitting structures EU-1, EU-2, and EU-3 of the light-emitting element OEL-a of the embodiment may be a green light-emitting structure EU-G or a green light-emitting structure EU-Ga (see Fig. 6A and Figure 6B ), and the remaining light-emitting structures may be a blue light-emitting structure EU-B and a blue light-emitting structure EU-Ba (see Fig. 7A and Figure 7B ). In the structure of the light emitting element OEL-a in which light is emitted in the upper surface direction of the second electrode EL2, the third light emitting structure EU-3 may correspond to the reference Fig. 6A or Figure 6B The green light emitting structure EU-G and the green light emitting structure EU-Ga described above, and the first light emitting structure EU-1 and the second light emitting structure EU-2 may correspond to the reference Fig. 7A or Figure 7B Described blue light-emitting structure EU-B and blue light-emitting structure EU-Ba.

[0276] The light emitting element OEL-a of the embodiment may include a first light emitting structure EU-1 and a second light emitting structure EU-2 which are disposed between the first electrode EL1 and the second electrode EL2 and are blue light emitting structures, and may include a third light emitting structure EU-3 which is disposed on the second light emitting structure EU-2 and is a green light emitting structure, wherein the third light emitting structure EU-3 may include a light emitting layer containing a low refractive index material. Accordingly, the light emitting element OEL-a of the embodiment may be in the first sub-light emitting layer EML-GB (see Fig. 6A or Figure 6B) includes a low refractive index material, and therefore, by increasing the light extraction efficiency in the third light emitting structure EU-3, it can have excellent luminous efficiency. The third light emitting structure EU-3 can include a low refractive index host material having a low refractive index characteristic in a sub-light emitting layer adjacent to the hole transport region, and therefore, can maintain good electrical characteristics and can have an optical effect of improved light extraction efficiency. Accordingly, the light emitting element OEL-a of the embodiment can have high luminous efficiency characteristics.

[0277] refer to Fig. 9 , the light emitting element OEL-b of the embodiment may include a first electrode EL1, a second electrode EL2 facing the first electrode EL1, a plurality of light emitting structures EU-1, EU-2, EU-3, EU-4 and EU-5 disposed between the first electrode EL1 and the second electrode EL2, and charge generation layers CGL-1, CGL-2, CGL-3 and CGL-4 disposed between the light emitting structures EU-1, EU-2, EU-3, EU-4 and EU-5. The first charge generation layer CGL-1 may be disposed between the first light emitting structure EU-1 and the second light emitting structure EU-2, the second charge generation layer CGL-2 may be disposed between the second light emitting structure EU-2 and the third light emitting structure EU-3, the third charge generation layer CGL-3 may be disposed between the third light emitting structure EU-3 and the fourth light emitting structure EU-4, and the fourth charge generation layer CGL-4 may be disposed between the fourth light emitting structure EU-4 and the fifth light emitting structure EU-5. The first to fourth charge generation layers CGL-1, CGL-2, CGL-3, and CGL-4 may each include an n-type charge generation layer n-CGL and a p-type charge generation layer p-CGL. The light emitting element OEL-b may include a capping layer CPL disposed on the second electrode EL2.

[0278] At least one of the light-emitting structures EU-1, EU-2, EU-3, EU-4 and EU-5 of the light-emitting element OEL-b of the embodiment may be a green light-emitting structure EU-G or a green light-emitting structure EU-Ga (see Fig. 6A and Figure 6B ), and the remaining light-emitting structures may be a blue light-emitting structure EU-B and a blue light-emitting structure EU-Ba (see Fig. 7A and Figure 7B ). In an embodiment, two of the light emitting structures EU-1, EU-2, EU-3, EU-4, and EU-5 of the light emitting element OEL-b may be green light emitting structures, and the remaining light emitting structures may be blue light emitting structures.

[0279] In the structure of the light emitting element OEL-b in which light is emitted in the upper surface direction of the second electrode EL2, the third light emitting structure EU-3 and the fifth light emitting structure EU-5 may each be a green light emitting structure. The third light emitting structure EU-3 may be referred to as a first green light emitting structure, and the fifth light emitting structure EU-5 may be referred to as a second green light emitting structure.

[0280] The first light emitting structure EU-1, the second light emitting structure EU-2, and the fourth light emitting structure EU-4 may correspond to the reference Fig. 7A or Figure 7B Described blue light-emitting structure EU-B and blue light-emitting structure EU-Ba.

[0281] The light emitting element OEL-b of the embodiment may include light emitting structures arranged in order of blue light emitting structure, blue light emitting structure, green light emitting structure, blue light emitting structure and green light emitting structure in the thickness direction (which is the third direction DR3) between the first electrode EL1 and the second electrode EL2.

[0282] In an embodiment, both the third light emitting structure EU-3 and the fifth light emitting structure EU-5 may be light emitting structures emitting green light, and the fifth light emitting structure EU-5 (or the second green light emitting structure) may correspond to the reference Fig. 6A or Figure 6B For example, in the light-emitting element OEL-b of the embodiment, the fifth light-emitting structure EU-5 disposed adjacent to the second electrode EL2 may include the green light-emitting structure EU-G and the green light-emitting structure EU-Ga according to the above embodiment (see Fig. 6A and Figure 6B ). For example, the fifth light-emitting structure EU-5 may include a hole transport region HTR-5, a light-emitting layer EML-5, and an electron transport region ETR-5. The fifth light-emitting structure EU-5 may include a first sub-light-emitting layer EML-GB containing a low refractive index material (see Fig. 6A and Figure 6B ) of the green light-emitting structure EU-G and the green light-emitting structure EU-Ga (see Fig. 6A and Figure 6B ), and therefore, can have high light extraction efficiency, and accordingly, the light emitting element OEL-b of the embodiment can have excellent light emitting efficiency characteristics.

[0283] The light emitting element OEL-b of the embodiment may also include a green light emitting structure EU-G and a green light emitting structure EU-Ga in the third light emitting structure EU-3 in addition to the fifth light emitting structure EU-5 (see Fig. 6A and Figure 6B ), the green light emitting structure EU-G and the green light emitting structure EU-Ga include a first sub-light emitting layer EML-GB containing a low refractive index material (see Fig. 6A and Figure 6B ). Because the fifth light emitting structure EU-5 and the third light emitting structure EU-3 each include a first sub-light emitting layer EML-GB including a low refractive index material (see Fig. 6A and Figure 6B ) of the green light-emitting structure EU-G and the green light-emitting structure EU-Ga (see Fig. 6A and Figure 6B ), so the fifth light-emitting structure EU-5 and the third light-emitting structure EU-3 can have an optical effect of high light extraction efficiency. The fifth light-emitting structure EU-5 and the third light-emitting structure EU-3 can include a low-refractive index host material having a low-refractive index characteristic in a sub-light-emitting layer adjacent to the hole transport region, and therefore, can maintain good electrical characteristics and can have an optical effect of improved light extraction efficiency. Accordingly, the light-emitting element OEL-b of the embodiment can have excellent luminous efficiency characteristics.

[0284] In reference Figure 5 , Figure 8 and Fig. 9 Among the multiple light-emitting structures included in the described light-emitting elements OEL, OEL-a, and OEL-b, the light-emitting structure emitting blue light may not include a low-refractive index material in the light-emitting layer. For example, among the light-emitting structures included in the light-emitting elements OEL, OEL-a, and OEL-b, the light-emitting layer of the light-emitting structure emitting blue light may not include a host material having a low-refractive index property.

[0285] The light-emitting element of the embodiment may include a plurality of light-emitting structures, and a low refractive index material may be included in the light-emitting layer of the light-emitting structure emitting green light in the light-emitting structure. In an embodiment, a sub-light-emitting layer separated from an electron transport region in a plurality of sub-light-emitting layers (which are included in the light-emitting layer of a green light-emitting structure located relatively upper in a light extraction direction among a plurality of stacked light-emitting structures) may include a low refractive index material. In an embodiment, a sub-light-emitting layer separated from an electron transport region in a plurality of sub-light-emitting layers included in the light-emitting layer of a green light-emitting structure may include a hole transport host material having a low refractive index characteristic, so as to have a high light extraction efficiency without degrading the electrical characteristics in the light-emitting layer, and the light-emitting element may have excellent luminous efficiency.

[0286] Hereinafter, the results of evaluation of characteristics of the light emitting element according to the embodiment of the present disclosure will be described with reference to Examples and Comparative Examples. The examples shown below are only for illustrative purposes to facilitate understanding of the present disclosure, and therefore, the scope of the present disclosure is not limited thereto.

[0287] <Manufacturing of Light Emitting Element>

[0288] The light-emitting elements of each of Examples 1-1 to 1-3, Example 2, and Comparative Examples 1 to 7 are manufactured as light-emitting elements connected in series by forming a first electrode on a glass substrate, forming four light-emitting structures and a charge generation layer arranged between the four light-emitting structures on the first electrode, and forming a second electrode and a capping layer.

[0289] based on Figure 5 The series-connected light-emitting elements of each of the embodiment and the comparative example were manufactured according to the light-emitting element structure explained in FIG.

[0290] A charge generation layer including an n-type charge generation layer and a p-type charge generation layer is provided between each of the stacked light emitting structures. 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) is doped with Li to form the n-type charge generation layer. In the n-type charge generation layer, BCP and Li are provided at a weight ratio of 90:10. The n-type charge generation layer is formed as Thickness.

[0291] On the n-type charge generation layer, a p-type charge generation layer was formed using dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN). The p-type charge generation layer was formed into Thickness.

[0292] The first electrode is formed to have a structure of ITO / Ag / ITO, and the second electrode is formed of AgMg. Figure 5 ), by forming N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPB) into A hole transport region is manufactured by forming 4,4',4"-tri(carbazole-9-yl)triphenylamine (TCTA) with a thickness of 75 on the NPB layer. In the fourth light-emitting structure EU-4, the hole transport region is formed by including NPB. Thickness.

[0293] In the first to third light emitting structures EU-1, EU-2 and EU-3 (see Figure 5 ), by including Thick 2,4,6-tris([1,1'-biphenyl]-3-yl)-1,3,5-triazine (T2T) layer and co-deposited by adding Liq to 2,4,6-tris(3-(pyrimidin-5-yl)phenyl)-1,3,5-triazine (TPM-TAZ) The electron transport region is formed by forming a thick layer. In the electron transport region, TPM-TAZ and Liq are included in a weight ratio of 5:5.

[0294] In the fourth light emitting structure EU-4 (see Figure 5 ), the electron transport region is formed to include Liq co-deposited by adding to TPM-TAZ Thick layers and including Yb Thick layer.

[0295] Each layer of the light emitting structure is formed by deposition under vacuum conditions. On the second electrode, compound P4 is used to form a layer with a thickness of The capping layer.

[0296] The structure of each of the light emitting structures in the example and the comparative example is as follows.

[0297] [Table 1]

[0298]

[0299]

[0300] In Table 1, those represented by HTR or HTR-L in each light-emitting structure correspond to the configuration of the hole transport region, and ETR corresponds to the configuration of the electron transport region. Those represented by EML-Ba or EML-Ba' correspond to the configuration of the blue light-emitting layer, and those represented by EML-G, EML-G', EML-G", and EML-G'" correspond to the configuration of the green light-emitting layer.

[0301] In Table 1, those indicated by HTR correspond to the formation of HTR-L corresponds to a configuration including a NPB having a thickness of The NPB layer and the low refractive index hole transport material LRM (ie, compound 1 in the above compound group 1) formed on the upper side of the NPB layer have a thickness of Auxiliary hole transport layer.

[0302] In the light-emitting structures of EU-1 to EU-3, ETR is obtained by co-deposition by adding Liq to TPM-TAZ. In the ETR, TPM-TAZ and Liq are included in a weight ratio of 5:5. In the light-emitting structures of EU-1 to EU-3, ETR is provided as In the light emitting structure of EU-4, the ETR is provided as a film including TPM-TAZ and Liq co-deposited in a weight ratio of 5:5. Thick layers and Yb Thick layer.

[0303] EML-Ba corresponds to a configuration of a blue light-emitting layer including two sub-light-emitting layers. EML-Ba corresponds to a configuration including a first blue host BH1 (ie, H1-1 described above) and a first blue dopant FD32 formed by co-depositing the first blue host BH1 (ie, H1-1 described above) and the first blue dopant FD32 at a weight ratio of 99:1. The lower sub-light emitting layer is formed by co-depositing the second blue host BH2 and the first blue dopant FD32 at a weight ratio of 99:1. The thickness of the upper sub-light-emitting layer is .

[0304] EML-Ba' corresponds to the configuration of the blue light-emitting layer, which further includes an additional auxiliary light-emitting layer in addition to the configuration of the lower sub-light-emitting layer and the upper sub-light-emitting layer of EML-Ba. The auxiliary light-emitting layer is arranged on the lower side of the lower sub-light-emitting layer, and corresponds to the configuration of the light-emitting layer including the low refractive index material LRM (i.e., compound 1 in the above-mentioned compound group 1), the first blue host BH1 and the first blue dopant FD32. In the auxiliary light-emitting layer, the ratio of the total weight of the low refractive index material LRM and the first blue host BH1 to the weight of the first blue dopant FD32 is 99:1, and in the light-emitting layer, the low refractive index material LRM and the first blue host BH1 are included in the same weight ratio of 1:1.

[0305] EML-G has a green light-emitting structure included in the light-emitting element of the embodiment. EML-G is a configuration that includes: a first sub-light-emitting layer including a low refractive index material LRM, a hole-transporting first host H4-12, an electron-transporting second host H3-23, and a green light-emitting dopant PD13; and a second sub-light-emitting layer disposed on the first sub-light-emitting layer and including a hole-transporting first host H4-12, an electron-transporting second host H3-23, and a green light-emitting dopant PD13.

[0306] In the first sub-light-emitting layer, the weight of the main body, which is the sum of the weight of the low refractive index material LRM, the weight of the hole transporting first main body H4-12 and the weight of the electron transporting second main body H3-23, and the weight of the green light-emitting dopant PD13 corresponds to 91:9. The weight ratio of the low refractive index material LRM, the hole transporting first main body H4-12 and the electron transporting second main body H3-23 is 1:0.5:0.5. In Examples 1-1 to 1-3, the thickness of the first sub-light-emitting layer is respectively and In Example 2, the thickness of the first sub-light emitting layer is

[0307] In the second sub-light-emitting layer, the ratio of the host weight, which is the sum of the weight of the hole-transporting first host H4-12 and the weight of the electron-transporting second host H3-23, to the weight of the green-light-emitting dopant PD13 corresponds to 91:9. The weight ratio of the hole-transporting first host H4-12 and the electron-transporting second host H3-23 is 1:1. In Examples 1-1 to 1-3, the thicknesses of the second sub-light-emitting layers are respectively and In Example 2, the thickness of the second sub-light emitting layer is

[0308] EML-G' corresponds to a configuration of a green light-emitting layer that does not include a low refractive index material. EML-G' includes a hole transporting first host H4-12, an electron transporting second host H3-23, and a green light-emitting dopant PD13. The ratio of the host weight, which is the sum of the weight of the hole transporting first host H4-12 and the weight of the electron transporting second host H3-23, to the weight of the green light-emitting dopant PD13 corresponds to 91:9. The weight ratio of the hole transporting first host H4-12 and the electron transporting second host H3-23 is 1:1. The thickness of EML-G' is

[0309] Compared with EML-G, EML-G" corresponds to a configuration in which a single green light-emitting layer is formed without being separated into sub-light-emitting layers. EML-G" is a single layer and has thickness. EML-G" includes a low refractive index material LRM, a hole transport first host H4-12, an electron transport second host H3-23 and a green light emitting dopant PD13, and the ratio of the host weight which is the sum of the weight of the hole transport first host H4-12 and the weight of the electron transport second host H3-23 to the weight of the green light emitting dopant PD13 corresponds to 91:9. The weight ratio of the hole transport first host H4-12 and the electron transport second host H3-23 is 1:1.

[0310] EML-G'' corresponds to a configuration of a green light-emitting layer including two sub-light-emitting layers. EML-G'' includes a lower sub-light-emitting layer disposed adjacent to the hole transport region HTR-L and an upper sub-light-emitting layer disposed on the lower sub-light-emitting layer. The lower sub-light-emitting layer includes a hole transport first host H4-12, an electron transport second host H3-23, and a green light-emitting dopant PD13, and the upper sub-light-emitting layer includes a low refractive index material LRM, a hole transport first host H4-12, an electron transport second host H3-23, and a green light-emitting dopant PD13. The thickness of each of the upper sub-light-emitting layer and the lower sub-light-emitting layer is In the lower sub-light emitting layer, the weight of the host as the sum of the weight of the hole transporting first host H4-12 and the weight of the electron transporting second host H3-23 corresponds to 91:9 with the weight of the green light emitting dopant PD13. The weight ratio of the hole transporting first host H4-12 and the electron transporting second host H3-23 is 1:1.

[0311] In the upper sub-light-emitting layer, the weight of the host, which is the sum of the weight of the low refractive index material LRM, the weight of the hole transporting first host H4-12, and the weight of the electron transporting second host H3-23, corresponds to 91:9 with the weight of the green light-emitting dopant PD13. The weight ratio of the low refractive index material LRM, the hole transporting first host H4-12, and the electron transporting second host H3-23 is 1:0.5:0.5.

[0312] The compounds used in the preparation of Examples and Comparative Examples are as follows.

[0313]

[0314] <Evaluation of Light Emitting Element>

[0315] The evaluation results of Examples 1-1 to 1-3, Example 2, and Comparative Examples 1 to 7 are shown in Table 2. In the evaluation results of the light-emitting elements in Table 2, the luminous efficiency and the driving voltage are expressed as relative comparative values ​​after measuring the luminous efficiency and the driving voltage corresponding to the luminance of 3500 nits. The luminous efficiency is expressed as a relative comparative value obtained by setting the luminous efficiency of Comparative Example 2 to 100%, and the driving voltage is expressed as a relative comparative value obtained by setting the driving voltage of Comparative Example 1 to 100%.

[0316] [Table 2]

[0317]

[0318]

[0319] Referring to Table 2, it can be seen that Examples 1-1 to 1-3 and Example 2 show excellent luminous efficiency characteristics compared to the comparative example. It can be confirmed that Examples 1-1 to 1-3 and Example 2 show low driving voltage characteristics or similar driving voltage characteristics compared to the comparative example.

[0320] Compared with Comparative Example 1 including a green light emitting structure without a low refractive index material, the embodiments show high luminous efficiency characteristics and low driving voltage characteristics. Compared with Comparative Example 2 including a low refractive index hole transport material in the hole transport region, the embodiments show high luminous efficiency characteristics and low driving voltage characteristics or the same driving voltage characteristics.

[0321] Compared with Comparative Example 1 or Comparative Example 2, the embodiment shows an effect of increased luminous efficiency while having a low driving voltage characteristic or the same driving voltage characteristic. This is determined to be due to the fact that in the case of an embodiment including a light-emitting layer containing a low refractive index material in a green light-emitting structure in a light-emitting element, light extracted from the light-emitting layer by the low refractive index material increases. That is, by including a low refractive index material in a sub-light-emitting layer constituting the light-emitting layer, the embodiment can show improved luminous efficiency characteristics due to optical effects such as increased light extraction efficiency.

[0322] Comparative Examples 3 to 5 have a light-emitting element structure, wherein one of the blue light-emitting structures includes a blue light-emitting layer containing a low refractive index material. Compared with the embodiment including a low refractive index material in the green light-emitting structure, in the case of Comparative Examples 3 to 5, the luminous efficiency characteristics are degraded, and the driving voltage is also higher than the driving voltage of the embodiment or is the same driving voltage characteristic. In the case of Comparative Examples 3 to 5, it can be seen that the luminous efficiency is reduced compared with the luminous efficiency of Comparative Examples 1 and 2. For example, in the case where the blue light-emitting layer includes a low refractive index material, it is determined that the degradation of the electrical characteristics is greater than the improvement of the optical effect (such as light extraction efficiency), and as a result, the luminous efficiency is reduced.

[0323] In Comparative Example 6, the green light emitting layer is provided as a single layer, and the green light emitting layer provided as a single layer includes a low refractive index material, and Comparative Example 7 is different from the embodiment in that the upper sub-light emitting layer in the sub-light emitting layer of the green light emitting layer includes a low refractive index material. Compared with the embodiment, Comparative Examples 6 and 7 show significantly deteriorated luminous efficiency characteristics and high driving voltage characteristics. This is determined to be due to the fact that a low refractive index material is included in the vicinity of the electron transport region ETR of the green light emitting structure, and the hole transport characteristics of the low refractive index material prevent the electrons provided from the electron transport region from being injected into the light emitting layer.

[0324] Therefore, by comparing the results of the embodiment with the results of Comparative Examples 1 to 7, it can be said that in the stacked structure of the same light-emitting structure, when a low refractive index material is included in the sub-light-emitting layer adjacent to the hole transport zone in the light-emitting layer of the green light-emitting structure, excellent light-emitting efficiency is shown due to the increase in light extraction efficiency.

[0325] The light emitting element of the embodiment may include a plurality of light emitting structures, and may include a material having a low refractive index characteristic in a light emitting layer of a light emitting structure emitting green light among the light emitting structures, and thus, may exhibit high efficiency characteristics.

[0326] The light emitting element of the display device of the embodiment may include a material having a low refractive index characteristic in a light emitting layer of a light emitting structure emitting green light among a plurality of light emitting structures, and thus, may exhibit excellent light emitting efficiency.

[0327] The above description is an example of the technical features of the present disclosure, and those skilled in the art to which the present disclosure belongs will be able to make various modifications and variations.Therefore, the above embodiments of the present disclosure can be implemented individually or in combination with each other.

[0328] Therefore, the embodiments disclosed in this disclosure are not intended to limit the technical spirit of this disclosure, but to describe the technical spirit of this disclosure, and the scope of the technical spirit of this disclosure is not limited to these embodiments. The protection scope of this disclosure should be interpreted by the claims, and should be interpreted as all technical spirits within the equivalent scope are included in the scope of this disclosure.

Claims

1. A light emitting element, comprising: a first electrode; a second electrode facing the first electrode; as well as A plurality of light-emitting structures are stacked between the first electrode and the second electrode, each of the plurality of light-emitting structures comprises a hole transport region, a light-emitting layer and an electron transport region, wherein At least one of the plurality of light emitting structures is a green light emitting structure that emits green light, and The light-emitting layer of the green light-emitting structure comprises: A first sub-light emitting layer including a low refractive index material having a refractive index value less than or equal to 1.7 at a wavelength of 460 nm; and The second sub-light emitting layer does not include the low-refractive-index material and is disposed on the first sub-light emitting layer. 2 . The light-emitting element according to claim 1 , wherein the first sub-light-emitting layer and the second sub-light-emitting layer each include a hole-transporting first host, an electron-transporting second host, and a green-light-emitting dopant. The light-emitting element according to claim 1 , wherein the low-refractive-index material is a hole-transporting host. 4 . The light-emitting element according to claim 1 , wherein the first sub-light-emitting layer is directly disposed on the hole transport region of the green light-emitting structure.

5. The light-emitting element according to claim 4, wherein the hole transport region of the green light-emitting structure comprises: hole transport layer; and An auxiliary hole transport layer is disposed on the hole transport layer and includes a low refractive index hole transport material having a refractive index value less than or equal to 1.7 at a wavelength of 460 nm. The light-emitting element according to claim 5 , wherein the first sub-light-emitting layer is directly disposed on the auxiliary hole transport layer. 7 . The light-emitting element according to claim 5 , wherein the low-refractive-index material and the low-refractive-index hole transport material are the same.

8. The light-emitting element according to claim 1, wherein the plurality of light-emitting structures comprises: A first light emitting structure disposed on the first electrode and emitting blue light; A second light emitting structure disposed on the first light emitting structure and emitting blue light; a third light emitting structure disposed on the second light emitting structure and emitting blue light; and The green light emitting structure is disposed on the third light emitting structure. 9 . The light emitting element according to claim 8 , wherein the light emitting layer of each of the first light emitting structure, the second light emitting structure, and the third light emitting structure comprises a hole transport host, an electron transport host, and a blue light emitting dopant.

10. The light emitting element according to claim 1, wherein the plurality of light emitting structures comprises: A first light emitting structure disposed on the first electrode and emitting blue light; A second light emitting structure disposed on the first light emitting structure and emitting blue light; and The green light emitting structure is disposed on the second light emitting structure.

11. The light-emitting element according to claim 1, wherein The plurality of light emitting structures include a first light emitting structure, a second light emitting structure, a third light emitting structure, and a fourth light emitting structure, each of which emits blue light and is sequentially stacked between the first electrode and the second electrode, The green light emitting structure comprises: a first green light emitting structure disposed between the second light emitting structure and the third light emitting structure; as well as a second green light emitting structure disposed on an upper side of the fourth light emitting structure, and The second green light emitting structure includes the first sub-light emitting layer including the low refractive index material and the second sub-light emitting layer not including the low refractive index material. 12 . The light-emitting element according to claim 1 , wherein the first sub-light-emitting layer and the second sub-light-emitting layer have the same thickness.

13. A light emitting element, comprising: a first electrode; a second electrode facing the first electrode; A plurality of light-emitting structures are sequentially stacked between the first electrode and the second electrode, each of the plurality of light-emitting structures comprising a hole transport region, a light-emitting layer and an electron transport region; as well as A charge generation layer is disposed between adjacent light emitting structures among the plurality of light emitting structures between the first electrode and the second electrode, wherein Two or more of the plurality of light emitting structures are blue light emitting structures that emit blue light, At least one of the plurality of light emitting structures is a green light emitting structure that emits green light, and The green light emitting structure comprises: a first sub-light emitting layer including a first host, a first dopant, and a low refractive index material having a refractive index value less than or equal to 1.7 at a wavelength of 460 nm; as well as The second sub-light emitting layer is disposed on the first sub-light emitting layer and includes a second host and a second dopant.

14. The light-emitting element according to claim 13, wherein the charge generation layer comprises: an n-type charge generation layer doped with an n-type dopant; and A p-type charge generation layer doped with a p-type dopant.

15. The light emitting element according to claim 13, wherein The second sub-light emitting layer does not include the low refractive index material, The first body and the second body are identical, and The first dopant and the second dopant are the same.

16. The light emitting element according to claim 13, wherein the plurality of light emitting structures comprises: a first blue light emitting structure disposed on the first electrode; a second blue light emitting structure disposed on the first blue light emitting structure; a third blue light emitting structure disposed on the second blue light emitting structure; and The green light emitting structure is disposed on the third blue light emitting structure.

17. A light-emitting element according to claim 16, wherein the hole transport region of the green light-emitting structure includes an auxiliary hole transport layer, which is directly arranged on the lower side of the first sub-light-emitting layer and includes a low refractive index hole transport material having a refractive index value less than or equal to 1.7 at a wavelength of 460 nm. 18 . The light emitting element according to claim 13 , wherein light emitted from the plurality of light emitting structures is emitted to an upper side of the second electrode. 19 . The light-emitting element according to claim 18 , wherein among the plurality of light-emitting structures, the green light-emitting structure is disposed adjacent to the second electrode. 20 . The light emitting element according to claim 16 , wherein the light emitting layer of each of the first blue light emitting structure, the second blue light emitting structure, and the third blue light emitting structure does not include the low refractive index material.

21. A display device, comprising: A light emitting element, outputting source light; and an optical layer disposed on the light emitting element and transmitting the source light or converting the wavelength of the source light, wherein The light-emitting element is the light-emitting element according to any one of claims 1 to 20.

22. The display device of claim 21, wherein the optical layer comprises a light management layer comprising quantum dots that convert the wavelength of the source light.

23. The display device according to claim 22, further comprising: a first pixel region emitting red light; a second pixel region emitting green light; and A third pixel region emitting blue light, wherein The first pixel region, the second pixel region, and the third pixel region do not overlap with each other in a plan view, and The light control layer comprises: A first light control component, disposed corresponding to the first pixel region and comprising a first quantum dot that converts the wavelength of the source light; a second light control member disposed corresponding to the second pixel region and comprising a second quantum dot that converts the wavelength of the source light; and The third light control component is arranged corresponding to the third pixel area.

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