Light-emitting element and electronic device

Abstract

Embodiments provide a light emitting element and an electronic device. The light emitting element includes a first electrode, a hole transport region, an emission layer, an electron transport region, and a second electrode. The hole transport region comprises a hole injection layer, at least one hole transport layer and an electron blocking layer with a first negative huge surface potential; and the electron transport region includes at least one electron transport layer and an electron injection layer. In a case where the light emitting element includes a plurality of hole transport layers, a hole transport layer adjacent to the emission layer has a second negative huge surface potential, and in a case where the light emitting element includes a plurality of electron transport layers, an electron transport layer adjacent to the second electrode has a first positive huge surface potential.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2024-0066710, filed on May 22, 2024, in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to a light emitting element and an electronic device including the same. BACKGROUND

[0004] Development of organic electroluminescent display devices and the like as image display devices is being continuously pursued. An organic electroluminescent display device is a so-called self-emissive display device in which holes and electrons injected from a first electrode and a second electrode, respectively, recombine in an emission layer so that a light emitting material including an organic compound emits light in the emission layer to achieve display, as compared with liquid crystal display devices and the like.

[0005] When an organic electroluminescent element is applied to a display device, there is a continuous need for an organic electroluminescent element having a low driving voltage. Therefore, there is a continuous need to develop a light emitting element capable of stably achieving such characteristics.

[0006] It will be appreciated that this Background section is intended to provide a useful background for understanding the technology. However, this Background section can also include ideas, concepts or recognitions not yet known or appreciated by those skilled in the art as of the respective effective filing date of the subject technology disclosed herein. SUMMARY

[0007] The present disclosure provides a light emitting element exhibiting a low capacitance.

[0008] The present disclosure also provides a display device providing enhanced display quality.

[0009] According to an embodiment, a light emitting element can include a first electrode; a hole transport region disposed on the first electrode; an emission layer disposed on the hole transport region; an electron transport region disposed on the emission layer; and a second electrode disposed on the electron transport region, the hole transport region can include a hole injection layer disposed on the first electrode; at least one hole transport layer disposed on the hole injection layer; and an electron blocking layer disposed on the hole transport layer and having a first negative giant surface potential, the electron transport region can include at least one electron transport layer disposed on the emission layer; and an electron injection layer disposed on the electron transport layer, the at least one hole transport layer can include a plurality of hole transport layers, and / or the at least one electron transport layer can include a plurality of electron transport layers; when the light emitting element includes the plurality of hole transport layers, a hole transport layer adjacent to the emission layer among the plurality of hole transport layers can have a second negative giant surface potential; and when the light emitting element includes the plurality of electron transport layers, an electron transport layer adjacent to the second electrode among the plurality of electron transport layers can have a first positive giant surface potential.

[0010] In an embodiment, the second negative giant surface potential can have an absolute value smaller than that of the first negative giant surface potential.

[0011] In an embodiment, the first negative giant surface potential can be equal to or smaller than about -10 mV / nm.

[0012] In an embodiment, the at least one hole transport layer can include a first hole transport layer disposed on the hole injection layer; and a second hole transport layer disposed on the first hole transport layer and having a second negative giant surface potential, and the second negative giant surface potential can be equal to or smaller than about -10 mV / nm.

[0013] In an embodiment, the first hole transport layer can have a second positive giant surface potential or a third negative giant surface potential; and an absolute value of the second positive giant surface potential and an absolute value of the third negative giant surface potential can each independently be equal to or smaller than about 10 mV / nm.

[0014] In an embodiment, the second positive giant surface potential and the third negative giant surface potential can each have a small absolute value than the second negative giant surface potential.

[0015] In an embodiment, the at least one hole transport layer can include a first hole transport layer disposed on the hole injection layer; a second hole transport layer disposed on the first hole transport layer; and a third hole transport layer disposed on the second hole transport layer, at least one of the second hole transport layer and the third hole transport layer can have a second negative giant surface potential, and the second negative giant surface potential can be equal to or smaller than about -10 mV / nm.

[0016] In embodiments, the second hole transport layer can have a second negative giant surface potential; the first hole transport layer and the third hole transport layer can each independently have a third positive giant surface potential or a fourth negative giant surface potential; and the absolute values of the third positive giant surface potential and the fourth negative giant surface potential can each independently be equal to or less than about 10 mV / nm.

[0017] In embodiments, the third hole transport layer can have a second negative giant surface potential; the first hole transport layer and the second hole transport layer can each independently have a third positive giant surface potential or a fourth negative giant surface potential; and the absolute values of the third positive giant surface potential and the fourth negative giant surface potential can each independently be equal to or less than about 10 mV / nm.

[0018] In embodiments, the emission layer can have a fourth positive giant surface potential.

[0019] In embodiments, the fourth positive giant surface potential can be equal to or greater than about 10 mV / nm.

[0020] In embodiments, the electron transport region can further include a hole blocking layer disposed between the emission layer and the electron transport layer.

[0021] In embodiments, the at least one electron transport layer can include: a first electron transport layer disposed on the emission layer; and a second electron transport layer disposed on the first electron transport layer and having a first positive giant surface potential, and the first positive giant surface potential can be equal to or greater than about 10 mV / nm.

[0022] In embodiments, the first electron transport layer can have a fifth positive giant surface potential or a fifth negative giant surface potential; and the absolute values of the fifth positive giant surface potential and the fifth negative giant surface potential can each independently be equal to or less than about 10 mV / nm.

[0023] In embodiments, the fifth positive giant surface potential and the fifth negative giant surface potential can each have a small absolute value than the first positive giant surface potential.

[0024] In embodiments, the at least one electron transport layer can include: a first electron transport layer disposed on the emission layer; a second electron transport layer disposed on the first electron transport layer; and a third electron transport layer disposed on the second electron transport layer, the second electron transport layer or the third electron transport layer can have a first positive giant surface potential, and the first positive giant surface potential can be equal to or greater than about 10 mV / nm.

[0025] In embodiments, the second electron transport layer can have a first positive giant surface potential; the first electron transport layer and the third electron transport layer can each independently have a sixth positive giant surface potential or a sixth negative giant surface potential; and the absolute value of the sixth positive giant surface potential and the absolute value of the sixth negative giant surface potential can each independently be equal to or less than about 10 mV / nm.

[0026] In embodiments, the third electron transport layer can have a first positive giant surface potential; the first electron transport layer and the second electron transport layer can each independently have a sixth positive giant surface potential or a sixth negative giant surface potential; and the absolute value of the sixth positive giant surface potential and the absolute value of the sixth negative giant surface potential can each independently be equal to or less than about 10 mV / nm.

[0027] In embodiments, the at least one hole transport layer can include a first hole transport layer disposed on the hole injection layer and a second hole transport layer disposed on the first hole transport layer and having a second negative giant surface potential; the at least one electron transport layer can include a first electron transport layer disposed on the emissive layer; the second negative giant surface potential can be equal to or less than about -10 mV / nm; and the absolute value of the giant surface potential of the first hole transport layer and the absolute value of the giant surface potential of the first electron transport layer can each independently be equal to or less than about 10 mV / nm.

[0028] In embodiments, the at least one hole transport layer can include a first hole transport layer disposed on the hole injection layer; the at least one electron transport layer can include a first electron transport layer disposed on the emissive layer and a second electron transport layer disposed on the first electron transport layer and having a first positive giant surface potential; the first positive giant surface potential can be equal to or greater than about 10 mV / nm; and the absolute value of the giant surface potential of the first hole transport layer and the absolute value of the giant surface potential of the first electron transport layer can each independently be equal to or less than about 10 mV / nm.

[0029] In embodiments, the at least one hole transport layer can include a first hole transport layer disposed on the hole injection layer and a second hole transport layer disposed on the first hole transport layer and having a second negative giant surface potential; the at least one electron transport layer can include a first electron transport layer disposed on the emissive layer and a second electron transport layer disposed on the first electron transport layer and having a first positive giant surface potential; the second negative giant surface potential can be equal to or less than about -10 mV / nm; the first positive giant surface potential can be equal to or greater than about 10 mV / nm; and the absolute value of the giant surface potential of the first hole transport layer and the absolute value of the giant surface potential of the first electron transport layer can each independently be equal to or less than about 10 mV / nm.

[0030] According to an embodiment, a light emitting element can include a first electrode; a hole transport region disposed on the first electrode; an emission layer disposed on the hole transport region; an electron transport region disposed on the emission layer; and a second electrode disposed on the electron transport region; the hole transport region can include a hole injection layer disposed on the first electrode; at least one hole transport layer disposed on the hole injection layer; and an electron blocking layer disposed on the hole transport layer and having a large surface potential equal to or less than about -10 mV / nm; the electron transport region can include at least one electron transport layer disposed on the emission layer; and an electron injection layer disposed on the electron transport layer; the at least one hole transport layer can include a plurality of hole transport layers, and / or the at least one electron transport layer can include a plurality of electron transport layers; when the light emitting element includes the plurality of hole transport layers, a hole transport layer adjacent to the emission layer among the plurality of hole transport layers can have a large surface potential equal to or less than about -10 mV / nm; and when the light emitting element includes the plurality of electron transport layers, an electron transport layer adjacent to the second electrode among the plurality of electron transport layers can have a large surface potential equal to or greater than about 10 mV / nm.

[0031] According to an embodiment, an electronic device can include a display device. The display device can include a circuit layer disposed on a base layer; a pixel definition film disposed on the circuit layer and having a plurality of pixel openings defined therein; and a plurality of light emitting elements disposed on the circuit layer; each light emitting element can include a first electrode, a hole transport region, an emission layer, an electron transport region, and a second electrode sequentially stacked; the hole transport region can include a hole injection layer disposed on the first electrode; at least one hole transport layer disposed on the hole injection layer; and an electron blocking layer disposed on the hole transport layer and having a first negative large surface potential; the electron transport region can include at least one electron transport layer disposed on the emission layer; and an electron injection layer disposed on the electron transport layer; the at least one hole transport layer can include a plurality of hole transport layers, and / or the at least one electron transport layer can include a plurality of electron transport layers; when the at least one hole transport layer includes the plurality of hole transport layers, a hole transport layer adjacent to the emission layer among the plurality of hole transport layers can have a second negative large surface potential; and when the at least one electron transport layer includes the plurality of electron transport layers, an electron transport layer adjacent to the second electrode among the plurality of electron transport layers can have a first positive large surface potential.

[0032] In an embodiment, the display device can further include a light control layer including quantum dots and a color filter layer disposed on the light control layer, wherein the color filter layer can include a first color filter transmitting red light, a second color filter transmitting green light, and a third color filter transmitting blue light.

[0033] According to an embodiment, a display device can include red, green, and blue light emitting regions different from each other in a plan view, a circuit layer disposed on a base layer, and a display element layer disposed on the circuit layer; the display element layer can include light emitting elements disposed to correspond to each of the red, green, and blue light emitting regions; at least one light emitting element can include a first electrode, a hole transport region, an emission layer, an electron transport region, and a second electrode sequentially stacked; the hole transport region can include a hole injection layer disposed on the first electrode, at least one hole transport layer disposed on the hole injection layer, and an electron blocking layer disposed on the hole transport layer and having a first negative giant surface potential; the electron transport region can include at least one electron transport layer disposed on the emission layer, and an electron injection layer disposed on the electron transport layer; the at least one hole transport layer can include a plurality of hole transport layers, and / or the at least one electron transport layer can include a plurality of electron transport layers; when the at least one hole transport layer includes a plurality of hole transport layers, a hole transport layer adjacent to the emission layer among the plurality of hole transport layers can have a second negative giant surface potential; and when the at least one electron transport layer includes a plurality of electron transport layers, an electron transport layer adjacent to the second electrode among the plurality of electron transport layers can have a first positive giant surface potential.

[0034] It will be understood that the above-described embodiments are illustrative only and not restrictive, and that the present disclosure is not limited to the above-described embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0035] The accompanying drawings, which are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure. The above and other aspects and features of the present disclosure will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, in which:

[0036] Figure 1 is a schematic plan view of a display device according to an embodiment;

[0037] Figure 2 is a schematic cross-sectional view of a display device according to an embodiment;

[0038] Figures 3 to 10 each is a schematic cross-sectional view of a light emitting element according to an embodiment;

[0039] Figures 11A to 11E each is a schematic cross-sectional view of a light emitting element according to an embodiment;

[0040] Figure 12 and Figure 13 each is a schematic cross-sectional view of a display device according to an embodiment;

[0041] Figure 14 is a schematic cross-sectional view of a display device according to an embodiment;

[0042] Figure 15 is a schematic cross-sectional view of a display device according to an embodiment. DETAILED DESCRIPTION

[0043] The present disclosure will now be described more fully with reference to the accompanying drawings, in which embodiments are shown. The present disclosure may, however, be embodied in different forms, and should not be construed as limited to the embodiments set forth in this disclosure. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0044] In the drawings, the size, thickness, proportions, and dimensions of elements can be exaggerated for the sake of description and clarity. The same reference numbers and characters always designate the same elements.

[0045] In the specification, it will be understood that when an element (or region, layer, part, etc.) is referred to as being “on” another element, “connected to” or “coupled to” another element, it can be directly on, directly connected to, or directly coupled to, the other element or one or more intervening elements can exist between the element and the other element. In a similar sense, when an element (or region, layer, part, etc.) is described as “covering” another element, it can directly cover the other element, or one or more intervening elements can exist between the element and the other element.

[0046] In the specification, when an element is “directly on” another element, “directly connected to” or “directly coupled to” another element, there is no intervening element. For example, “directly on” can mean that two layers or two elements are disposed without an additional element such as an adhesive element between them.

[0047] As used herein, the terms “a,” “an,” and “the” are intended to include both singular and plural forms, unless the context clearly indicates otherwise.

[0048] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. For example, “A and / or B” can be construed to mean “A, B, or A and B.” The terms “and” and “or” can be used in the conjunctive or disjunctive sense and can be understood to mean “and / or.”

[0049] In the specification and claims, the term "at least one", for purposes of interpretation of the specification and claims, shall not be construed as limiting of having a meaning exclusively; rather, it shall be interpreted to retain its ordinary meaning along with the meaning implied by the patent statute; that is, the term "at least one" will be interpreted to mean one or more, depending on the context and interpretation by the patent statute.

[0050] It will be understood that, although the terms first, second, etc. can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, a first element could be termed a second element without departing from the teachings of the present disclosure. Similarly, where a first element is described as being capable of being formed from a second element, it will be understood that the first element can be directly formed from the second element, or that the first element can be formed from the second element indirectly, e.g., through the use of one or more intermediate elements.

[0051] For purposes of the description hereinafter, spatial or directional terms, such as "above", "below", "upper", "lower", "up", "down", "left", "right", "horizontal", "vertical", and the like, relative to the illustrated orientation of the device as placed in use or operation, are used. It is understood that the spatial and directional terms are used with respect to the orientations in the drawings. The spatial and directional terms do not imply a

[0052] In view of the discussion regarding measurements and errors associated with measuring amounts recited (i.e., limitations of the measurement system), the term "about" or "approximately", as used herein, includes the recited value and means within an acceptable range of deviation from the recited value as determined by one of ordinary skill in the art. For example, "about" can mean within one or more standard deviations, or within ±20%, ±10%, or ±5% of the recited value.

[0053] It should be understood that the terms “comprises”, “comprising”, “includes”, “including”, “has”, “having”, “contains”, “containing”, and the like, are intended to be interpreted as specifying the presence of stated features, integers, steps, or components, but not precluding the presence or addition of one or more other features, integers, steps, components, or groups thereof.

[0054] Unless otherwise defined or implied herein, all terms used are intended to have the same meaning as commonly understood by one of ordinary skill in the art in the field to which this disclosure belongs. It will be further understood that, unless otherwise explicitly defined, terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and are not to be interpreted in an idealized or overly formal sense.

[0055] In the specification, the term “substituted or unsubstituted” can describe a group substituted with at least one substituent selected from the group consisting of a deuterium atom, a halogen atom, a cyano group, a nitro group, an amino group, an amine group, a silyl group, an oxyl group, a sulfenyl group, a sulfinyl group, a sulfonyl group, a carbonyl group, a boron group, a phosphine oxide group, a phosphine sulfide group, an alkyl group, an alkenyl group, an alkynyl group, a hydrocarbyl group, an aryl group, and a heterocyclic group. Each of the above-listed substituents can be substituted or unsubstituted by itself. For example, a biphenyl group can be interpreted as an aryl group, or it can be interpreted as a phenyl group substituted with a phenyl group.

[0056] In the specification, the term “bonded with adjacent groups to form a ring” can refer to a group bonded with adjacent groups to form a substituted or unsubstituted hydrocarbon ring or a substituted or unsubstituted heterocyclic ring. The hydrocarbon ring can be aliphatic or aromatic. The heterocyclic ring can be aliphatic or aromatic. The hydrocarbon ring and the heterocyclic ring can each independently be monocyclic or polycyclic. The ring formed by the adjacent groups bonded to each other can itself be connected to another ring to form a spiro structure.

[0057] In the specification, the term “adjacent groups” can be interpreted as substituents that substitute atoms directly connected to an atom substituted with a corresponding substituent, as another substituent that substitutes an atom substituted with a corresponding substituent, or as substituents that are spatially located closest to a corresponding substituent. For example, the two methyl groups in 1,2-dimethylbenzene can be interpreted as “adjacent groups” to each other, and the two ethyl groups in 1,1-diethylcyclopentane can be interpreted as “adjacent groups” to each other. For example, the two methyl groups in 4,5-dimethylphenanthrene can be interpreted as “adjacent groups” to each other.

[0058] In the specification, examples of the halogen atom can include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0059] In the specification, the alkyl group can be linear or branched. The number of carbon atoms in the alkyl group can be 1 to 50, 1 to 30, 1 to 20, 1 to 10, or 1 to 6. Examples of the alkyl group can include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, isobutyl, 2-ethylbutyl, 3,3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, t-pentyl, 1-methylpentyl, 3-methylpentyl, 2-ethylpentyl, 4-methyl-2-pentyl, n-hexyl, 1-methylhexyl, 2-ethylhexyl, 2-butylhexyl, n-heptyl, 1-methylheptyl, 2,2-dimethylheptyl, 2-ethylheptyl, 2-butylheptyl, n-octyl, t-octyl, 2-ethyloctyl, 2-butyloctyl, 2-hexyloctyl, 3,7-dimethyloctyl, n-nonyl, n-decyl, adamantyl, 2-ethyldecyl, 2-butyldodecyl, 2-hexyldecyl, 2-octyldecyl, n-undecyl, n-dodecyl, 2-ethyldodecyl, 2-butyldodecyl, 2-hexyldodecyl, 2-octyldodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, 2-ethylhexadecyl, 2-butyihexadecyl, 2-hexylhexadecyl, 2-octylhexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, 2-ethyleicosyl, 2-butyleicosyl, 2-hexyleicosyl, 2-octyleicosyl, n-uneicosyl, n-docosyl, n-tricosyl, n-tetracosyl, n-pentacosyl, n-hexacosyl, n-heptacosyl, n-octacosyl, n-nonacosyl, n-triacontyl, and the like, but the embodiments are not limited thereto.

[0060] In the specification, the cycloalkyl group can be a cyclic alkyl group. The number of carbon atoms in the cycloalkyl group can be 3 to 50, 3 to 30, 3 to 20, or 3 to 10. Examples of the cycloalkyl group can include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, 4-t-butylcyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, norbornyl, 1-adamantyl, 2-adamantyl, isobornyl, bicycloheptyl, and the like, but the embodiments are not limited thereto.

[0061] In the specification, the alkenyl group can be a hydrocarbon group including at least one carbon-carbon double bond in the middle or at the end of an alkyl group having 2 or more carbon atoms. The alkenyl group can be linear or branched. The number of carbon atoms in the alkenyl group is not particularly limited, and can be 2 to 30, 2 to 20, or 2 to 10. Examples of the alkenyl group can include ethenyl, 1-butenyl, 1-pentenyl, 1,3-butadienyl, phenylethenyl, phenylethenyl, and the like, but the embodiments are not limited thereto.

[0062] In the specification, the alkynyl group can be a hydrocarbon group comprising at least one carbon-carbon triple bond at the middle or end of an alkyl group having two or more carbon atoms. The alkynyl group can be straight-chain or branched. There is no particular limitation on the number of carbon atoms in the alkynyl group, and it can be 2 to 30, 2 to 20, or 2 to 10. Examples of alkynyl groups can include ethynyl, propynyl, etc., but the embodiments are not limited thereto.

[0063] In the specification, the hydrocarbon cyclic group can be any functional group or substituent derived from an aliphatic hydrocarbon ring. For example, the hydrocarbon cyclic group can be a saturated hydrocarbon cyclic group having 5 to 20 cyclic carbon atoms.

[0064] In the specification, the aryl group can be any functional group or substituent derived from an aromatic ring. The aryl group can be monocyclic or polycyclic. The number of cyclic carbon atoms in the aryl group can be 6 to 30, 6 to 20, or 6 to 15. Examples of aryl groups include phenyl, naphthyl, fluorenyl, anthraceneyl, phenanthryl, biphenyl, terphenyl, tetraphenyl, pentaphenyl, hexaphenyl, benzo[a]phenanthryl, pyrene, benzo[a]fluoranyl, and so on. The examples are similar, but the embodiments are not limited thereto.

[0065] In this specification, the fluorene group may be substituted, and two substituents may bond together to form a spirocyclic structure. Examples of substituted fluorene groups may include the groups shown below. However, the embodiments are not limited thereto.

[0066]

[0067] In the specification, the heterocyclic group can be any functional group or substituent derived from a ring including at least one of B, O, N, P, Si, S, and Se as a heteroatom. The heterocyclic group can be aliphatic or aromatic. The aromatic heterocyclic group can be a heteroaryl. Aliphatic heterocycles and aromatic heterocycles can each be monocyclic or polycyclic independently.

[0068] If a heterocyclic group contains two or more heteroatoms, the two or more heteroatoms may be the same or different from each other. The number of cyclic carbon atoms in a heterocyclic group may be 2 to 30, 2 to 20, or 2 to 10.

[0069] Examples of aliphatic heterocyclic groups may include oxetane, thiohepane, pyrrolidinyl, piperidinyl, tetrahydrofuranyl, tetrahydrothiophenyl, thiocyclopentyl, tetrahydropyranyl, 1,4-dioxane, etc., but the examples are not limited thereto.

[0070] Examples of the heteroaryl group can include thienyl, furanyl, pyrrolyl, imidazolyl, pyridyl, bipyridyl, pyrimidyl, triazinyl, triazolyl, acridinyl, pyridazinyl, pyrazinyl, quinolinyl, quinazolinyl, quinoxalinyl, phenoxazinyl, phthalazinyl, pyridopyrimidyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolinyl, indolyl, carbazolyl, N-arylcarbazolyl, N-heteroarylcarbazolyl, N-alkylcarbazolyl, benzoxazolyl, benzimidazolyl, benzothiazolyl, benzocarbazolyl, benzothiophenyl, dibenzothiophenyl, thienothiophenyl, benzofuranyl, phenanthrolinyl, thiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, thiadiazolyl, phenothiazinyl, dibenzothiopholyl, dibenzofuranyl, and the like, but the embodiments are not limited thereto.

[0071] In the specification, the above description of the aryl group can be applied to the arylene group, with the exception that the arylene group is a divalent group. In the specification, the above description of the heteroaryl group can be applied to the heteroarylene group, with the exception that the heteroarylene group is a divalent group.

[0072] In the specification, the silyl group can be an alkylsilyl group or an arylsilyl group. Examples of the silyl group can include trimethylsilyl, triethylsilyl, t-butyldimethylsilyl, vinyl dimethylsilyl, propyldimethylsilyl, triphenylsilyl, diphenylsilyl, phenylsilyl, and the like, but the embodiments are not limited thereto.

[0073] In the specification, the number of carbon atoms in the carbonyl group is not particularly limited, and can be 1 to 40, 1 to 30, or 1 to 20. For example, the carbonyl group can have one of the following structures, but the embodiments are not limited thereto.

[0074]

[0075] In the specification, the number of carbon atoms in the sulfinyl group or the sulfonyl group is not particularly limited, and can be 1 to 30. The sulfinyl group can be an alkylsulfinyl group or an arylsulfinyl group. The sulfonyl group can be an alkylsulfonyl group or an arylsulfonyl group.

[0076] In the specification, the sulfenyl group can be an alkylsulfenyl group or an arylsulfenyl group. The sulfenyl group can be a sulfur atom bonded to an alkyl group or an aryl group as defined above. Examples of the sulfenyl group can include methylsulfenyl, ethylsulfenyl, propylsulfenyl, pentylsulfenyl, hexylsulfenyl, octylsulfenyl, dodecylsulfenyl, cyclopentylsulfenyl, cyclohexylsulfenyl, phenylsulfenyl, naphthylsulfenyl, but the embodiments are not limited thereto.

[0077] In the specification, an oxy group can be an oxygen atom bonded to an alkyl group or an aryl group as defined above. The oxy group can be an alkoxy group or an aryloxy group. The alkoxy group can be linear, branched, or cyclic. The number of carbon atoms in the alkoxy group is not particularly limited, and can be, for example, 1 to 20 or 1 to 10. Examples of the oxy group can include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, a butoxy group, a pentoxy group, a hexyloxy group, an octyloxy group, a nonyloxy group, a decyloxy group, a benzyloxy group, and the like, but the embodiments are not limited thereto.

[0078] In the specification, a boron group can be a boron atom bonded to an alkyl group or an aryl group as defined above. The boron group can be an alkylboron group or an arylboron group. Examples of the boron group can include a dimethylboron group, a tert-butylmethylboron group, a diphenylboron group, a phenylboron group, and the like, but the embodiments are not limited thereto.

[0079] In the specification, the number of carbon atoms in the amine group is not particularly limited, and can be 1 to 30. The amine group can be an alkylamine group or an arylamine group. Examples of the amine group can include a methylamine group, a dimethylamine group, a phenylamine group, a diphenylamine group, a naphthylamine group, a 9-methyl-anthracenylamine group, and the like, but the embodiments are not limited thereto.

[0080] In the specification, the alkyl group within the alkylthio group, the alkylsulfoxy group, the alkylaryl group, the alkylamino group, the alkylboron group, the alkylsilyl group, or the alkylamine group can be the same as the examples of the alkyl group described above.

[0081] In the specification, the aryl group within the aryloxy group, the arylthio group, the arylsulfoxy group, the arylamino group, the arylboron group, the arylsilyl group, or the arylamine group can be the same as the examples of the aryl group described above.

[0082] In the specification, the direct connection can be a single bond.

[0083] In the specification, the symbols and “-*” each represent a bond to an adjacent atom in the corresponding formula or moiety.

[0084] Hereinafter, embodiments will be described with reference to the accompanying drawings.

[0085] Figure 1 is a schematic plan view of a display device DD according to an embodiment. Figure 2 is a schematic cross-sectional view of the display device DD according to an embodiment. Figure 2 is a schematic cross-sectional view of a portion taken along a virtual line I-I’ in Figure 1

[0086] ​The display device DD can include a display panel DP and an optical layer PP disposed on the display panel DP. The display panel DP includes light emitting elements ED-1, ED-2, and ED-3. The display device DD can include a plurality of light emitting elements ED-1, ED-2, and ED-3. The optical layer PP can be disposed on the display panel DP to control light of external light reflected at the display panel DP. The optical layer PP can include, for example, a polarizing layer or a color filter layer. Although not shown in the drawings, in an embodiment, the optical layer PP can be omitted from the display device DD.

[0087] A base substrate BL can be disposed on the optical layer PP. The base substrate BL can provide a base surface on which the optical layer PP is disposed. The base substrate BL can be a glass substrate, a metal substrate, a plastic substrate, or the like. However, embodiments are not limited thereto, and the base substrate BL can include an inorganic layer, an organic layer, or a composite material layer. Although not shown in the drawings, in an embodiment, the base substrate BL can be omitted.

[0088] The display device DD according to embodiments can further include a filler layer (not shown). The filler layer (not shown) can be disposed between the display device layer DP-ED and the base substrate BL. The filler layer (not shown) can be an organic material layer. The filler layer (not shown) can include at least one of an acrylic resin, a silicone resin, and an epoxy resin.

[0089] The display panel DP can include a base layer BS, a circuit layer DP-CL provided on the base layer BS, and a display device layer DP-ED. The display device layer DP-ED can include a pixel definition film PDL, light emitting elements ED-1, ED-2, and ED-3 disposed between portions of the pixel definition film PDL, and a encapsulation layer TFE disposed on the light emitting elements ED-1, ED-2, and ED-3.

[0090] The base layer BS can provide a base surface on which the display device layer DP-ED is disposed. The base layer BS can be a glass substrate, a metal substrate, a plastic substrate, or the like. However, embodiments are not limited thereto, and the base layer BS can include an inorganic layer, an organic layer, or a composite material layer.

[0091] In an embodiment, the circuit layer DP-CL is disposed on the base layer BS, and the circuit layer DP-CL can include transistors (not shown). The transistors (not shown) can each include a control electrode, an input electrode, and an output electrode. For example, the circuit layer DP-CL can include switching transistors and driving transistors for driving the light emitting elements ED-1, ED-2, and ED-3 of the display device layer DP-ED.

[0092] The light emitting elements ED-1, ED-2, and ED-3 can each have a structure according to the following description. Figures 3 to 6The structure of the light-emitting element ED of any one of the drawings. The light-emitting elements ED-1, ED-2, and ED-3 can each include a first electrode EL1, a hole transport region HTR, a respective one of the emission layers EML-R, EML-G, and EML-B, an electron transport region ETR, and a second electrode EL2.

[0093] Figure 2 An embodiment in which the emission layers EML-R, EML-G, and EML-B of the light-emitting elements ED-1, ED-2, and ED-3 are provided in the openings OH defined in the pixel definition film PDL and the hole transport regions HTR, the electron transport regions ETR, and the second electrodes EL2 are each provided as a common layer for the light-emitting elements ED-1, ED-2, and ED-3 is shown. However, embodiments are not limited thereto. Although not shown in Figure 2 In an embodiment, the hole transport regions HTR and the electron transport regions ETR can each be provided by patterning in the openings OH defined in the pixel definition film PDL, although not shown in

[0094] The encapsulation layer TFE can cover the light-emitting elements ED-1, ED-2, and ED-3. The encapsulation layer TFE can seal the display device layer DP-ED. The encapsulation layer TFE can be a thin film encapsulation layer. The encapsulation layer TFE can be formed of a single layer or a plurality of layers. The encapsulation layer TFE can include at least one insulating layer. The encapsulation layer TFE according to an embodiment can include at least one inorganic film (hereinafter, an encapsulation inorganic film). The encapsulation layer TFE according to an embodiment can include at least one organic film (hereinafter, an encapsulation organic film) and at least one encapsulation inorganic film.

[0095] The encapsulation inorganic film protects the display device layer DP-ED from moisture and / or oxygen, and the encapsulation organic film protects the display device layer DP-ED from foreign substances such as dust particles. The encapsulation inorganic film can include silicon nitride, silicon oxynitride, silicon oxide, titanium oxide, or aluminum oxide, or the like, although embodiments are not limited thereto. The encapsulation organic film can include an acrylic compound or an epoxy compound, or the like. The encapsulation organic film can include a photopolymerizable organic material, although embodiments are not limited thereto.

[0096] The encapsulation layer TFE can be provided on the second electrode EL2 and can be provided to fill the openings OH.

[0097] Reference Figure 1 and Figure 2The display device DD can include a non-light emitting region NPXA and light emitting regions PXA-R, PXA-G, and PXA-B. The light emitting regions PXA-R, PXA-G, and PXA-B can be regions that emit light generated by the light emitting elements ED-1, ED-2, and ED-3, respectively. The light emitting regions PXA-R, PXA-G, and PXA-B can be spaced apart from each other in a plan view.

[0098] The light emitting regions PXA-R, PXA-G, and PXA-B can be regions separated from each other by the pixel defining film PDL. The non-light emitting region NPXA can be a region between the adjacent light emitting regions PXA-R, PXA-G, and PXA-B, and the non-light emitting region NPXA can correspond to the pixel defining film PDL. In an embodiment, the light emitting regions PXA-R, PXA-G, and PXA-B can each correspond to a pixel. The pixel defining film PDL can separate the light emitting elements ED-1, ED-2, and ED-3. The emission layers EML-R, EML-G, and EML-B of the light emitting elements ED-1, ED-2, and ED-3 can be disposed in the openings OH defined in the pixel defining film PDL and separated from each other.

[0099] The light emitting regions PXA-R, PXA-G, and PXA-B can be arranged in groups according to the colors of the light generated from the light emitting elements ED-1, ED-2, and ED-3. In an embodiment according to Figure 1 and Figure 2 In the display device DD of the embodiment shown in FIGS. 1A and 1B, three light emitting regions PXA-R, PXA-G, and PXA-B that respectively emit red light, green light, and blue light are shown as an example. For example, the display device DD can include a red light emitting region PXA-R, a green light emitting region PXA-G, and a blue light emitting region PXA-B that are different from each other.

[0100] In the display device DD according to an embodiment, the light emitting elements ED-1, ED-2, and ED-3 can emit light having different wavelengths from each other. For example, in an embodiment, the display device DD can include a first light emitting element ED-1 that emits red light, a second light emitting element ED-2 that emits green light, and a third light emitting element ED-3 that emits blue light. For example, the red light emitting region PXA-R, the green light emitting region PXA-G, and the blue light emitting region PXA-B of the display device DD can respectively correspond to the first light emitting element ED-1, the second light emitting element ED-2, and the third light emitting element ED-3.

[0101] However, embodiments are not limited thereto, and the first light emitting element ED-1, the second light emitting element ED-2, and the third light emitting element ED-3 can emit light in the same wavelength range, or at least one light emitting element can emit light in a wavelength range different from the wavelength range of light emitted by the remaining light emitting elements. For example, the first light emitting element ED-1, the second light emitting element ED-2, and the third light emitting element ED-3 can each emit blue light.

[0102] The light emitting regions PXA-R, PXA-G, and PXA-B in the display apparatus DD according to embodiments can be arranged in a stripe configuration. Referring to Figure 1 , the red light emitting regions PXA-R, the green light emitting regions PXA-G, and the blue light emitting regions PXA-B can be arranged along the second direction axis DR2, respectively. In another embodiment, the red light emitting regions PXA-R, the green light emitting regions PXA-G, and the blue light emitting regions PXA-B can be arranged in this repeating order along the first direction axis DR1.

[0103] Figure 1 and Figure 2 It is shown that the light emitting regions PXA-R, PXA-G, and PXA-B all have similar areas, but embodiments are not limited thereto. In embodiments, the light emitting regions PXA-R, PXA-G, and PXA-B can differ from each other in size or shape according to the wavelength range of emitted light. The area of the light emitting regions PXA-R, PXA-G, and PXA-B can be the area defined in a plan view by the first direction axis DR1 and the second direction axis DR2. The third direction axis DR3 can be perpendicular to the plane defined by the first direction axis DR1 and the second direction axis DR2.

[0104] The arrangement of the light emitting regions PXA-R, PXA-G, and PXA-B is not limited to the configuration shown in Figure 1 , and the order in which the red light emitting regions PXA-R, the green light emitting regions PXA-G, and the blue light emitting regions PXA-B are arranged can be provided in various combinations according to the display quality characteristics required of the display apparatus DD. For example, the light emitting regions PXA-R, PXA-G, and PXA-B can be arranged in a five-patch tile configuration such as Pen or in a diamond configuration such as Diamond .

[0105] The areas of the light emitting regions PXA-R, PXA-G, and PXA-B can differ from each other in size. For example, in embodiments, the area of the green light emitting regions PXA-G can be smaller than the area of the blue light emitting regions PXA-B, but embodiments are not limited thereto.

[0106] Hereinafter, Figures 3 to 10Each is a schematic cross-sectional view of a light-emitting element ED according to an embodiment. The light-emitting element ED according to an embodiment can each include a first electrode EL1, a second electrode EL2 facing the first electrode EL1, and at least one functional layer provided between the first electrode EL1 and the second electrode EL2.

[0107] The light-emitting element ED can include, as the at least one functional layer, a hole transport region HTR, an emission layer EML, and an electron transport region ETR, which can be stacked in the following order. As Figure 3 indicated in FIG. 1A, the light-emitting element ED according to an embodiment can include a first electrode EL1, a hole transport region HTR, an emission layer EML, an electron transport region ETR, and a second electrode EL2.

[0108] In comparison with Figure 3 , Figure 4 is a schematic cross-sectional view of a light-emitting element ED in which the hole transport region HTR includes a hole injection layer HIL, a hole transport layer HTL, and an electron blocking layer EBL, and the electron transport region ETR includes an electron injection layer EIL and an electron transport layer ETL. In comparison with Figure 3 , Figure 5 is a schematic cross-sectional view of a light-emitting element ED in which the hole transport region HTR includes a hole injection layer HIL, a hole transport layer HTL, and an electron blocking layer EBL, and the electron transport region ETR includes an electron injection layer EIL, an electron transport layer ETL, and a hole blocking layer HBL.

[0109] In comparison with Figure 4 , Figure 6 is a schematic cross-sectional view of a light-emitting element ED in which the hole transport layer HTL includes a hole transport layer HTL1 and HTL2. In comparison with Figure 4 , Figure 7 is a schematic cross-sectional view of a light-emitting element ED in which the electron transport layer ETL includes an electron transport layer ETL1 and ETL2. In comparison with Figure 4 , Figure 8 is a schematic cross-sectional view of a light-emitting element ED in which the hole transport layer HTL includes a hole transport layer HTL1 and HTL2, and the electron transport layer ETL includes an electron transport layer ETL1 and ETL2. In comparison with Figure 4 , Figure 9 is a schematic cross-sectional view of a light-emitting element ED in which the hole transport layer HTL includes a hole transport layer HTL1, HTL2, and HTL3, and the electron transport layer ETL includes an electron transport layer ETL1, ETL2, and ETL3. In comparison with Figure 3 , Figure 10 is a schematic cross-sectional view of a light-emitting element ED in which a capping layer CPL is provided on the second electrode EL2.

[0110] The first electrode EL1 is conductive. The first electrode EL1 can be formed of a metallic material, a metal alloy, or a conductive compound. The first electrode EL1 can be an anode or a cathode. However, the embodiments are not limited thereto. In an embodiment, the first electrode EL1 can be a pixel electrode. The first electrode EL1 can be a transmissive electrode, a semi-transmissive / semi-reflective electrode, or a reflective electrode. The first electrode EL1 can include at least one of Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF, Mo, Ti, W, In, Sn, Zn, their oxides, their compounds, and mixtures thereof.

[0111] If the first electrode EL1 is a transmissive electrode, it may comprise a transparent metal oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or indium tin zinc oxide (ITZO). If the first electrode EL1 is a semi-transmissive / semi-reflective electrode or a reflective electrode, it may comprise Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF, Mo, Ti, W, their compounds, or mixtures thereof (e.g., a mixture of Ag and Mg), or a material having a multilayer structure such as LiF / Ca (a stacked structure of LiF and Ca) or LiF / Al (a stacked structure of LiF and Al). In another embodiment, the first electrode EL1 may have a multilayer structure comprising a reflective or semi-transmissive / semi-reflective film formed from the aforementioned materials and a transparent conductive film formed from ITO, IZO, ZnO, ITZO, etc. For example, the first electrode EL1 may have a three-layer structure of ITO / Ag / ITO, but the embodiments are not limited thereto. In an embodiment, the first electrode EL1 may include the aforementioned metallic material, a combination of at least two of the aforementioned metallic materials, or an oxide of the aforementioned metallic material, etc. The thickness of the first electrode EL1 may be approximately... up to approximately Within a certain range. For example, the thickness of the first electrode EL1 can be approximately... up to approximately Within the range.

[0112] In such Figures 3 to 10 In the light-emitting element ED shown according to an embodiment, a hole transport region HTR can be provided on the first electrode EL1. 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 EBL.

[0113] The hole transport region HTR can have a structure including a plurality of layers including different materials. In an embodiment, the hole transport region HTR can have a structure in which a hole injection layer HIL / hole transport layer HTL / electron blocking layer EBL are stacked from the first electrode EL1 in the order as stated, but embodiments are not limited thereto.

[0114] The hole transport region HTR can be formed using various methods such as a vacuum deposition method, a spin coating method, a casting method, a Langmuir-Blodgett (LB) method, an inkjet printing method, a laser printing method, and a laser induced thermal imaging (LITI) method.

[0115] The thickness of the hole transport region HTR can be in the range of about to about . For example, the thickness of the hole transport region HTR can be in the range of about to about . When the hole transport region HTR includes the hole injection layer HIL, the hole injection layer HIL can have a thickness in the range of about to about . When the hole transport region HTR includes the hole transport layer HTL, the hole transport layer HTL can have a thickness in the range of about to about . When the hole transport region HTR includes the electron blocking layer EBL, the electron blocking layer EBL can have a thickness in the range of about to about . If the thicknesses of the hole transport region HTR, the hole injection layer HIL, the hole transport layer HTL, and the electron blocking layer EBL satisfy the above ranges, satisfactory hole transport properties can be achieved without a significant increase in driving voltage.

[0116] An electron blocking layer EBL according to an embodiment will be described. The electron blocking layer EBL can prevent injection of electrons from the electron transport region ETR to the hole transport region HTR. Among the layers of the hole transport region HTR, the electron blocking layer EBL can be disposed adjacent to (e.g., directly adjacent to) the emission layer EML.

[0117] The electron blocking layer EBL according to an embodiment can have a giant surface potential. For example, the electron blocking layer EBL can have a negative giant surface potential. In an embodiment, the electron blocking layer EBL can include a compound having a negative giant surface potential.

[0118] In the specification, the giant surface potential can be a surface potential induced in an organic layer when an organic material having a dipole is aligned in one direction due to an electric field generated by the dipole. Hereinafter, the giant surface potential can be referred to as "GSP".

[0119] In the specification, a negative giant surface potential indicates a surface potential that induces positive charges toward the first electrode EL1, for example, in the anode direction. In the specification, a positive giant surface potential indicates a surface potential that induces negative charges toward the first electrode EL1, for example, in the anode direction.

[0120] The negative giant surface potential and the positive giant surface potential can each be a potential gradient of a surface potential obtained by a Kelvin probe according to the thickness of the organic layer. The negative giant surface potential can be a giant surface potential having a negative slope, and the positive giant surface potential can be a giant surface potential having a positive slope. Hereinafter, the negative giant surface potential can be referred to as a "negative GSP", and the positive giant surface potential can be referred to as a "positive GSP".

[0121] In an embodiment, the electron blocking layer EBL can have a first negative GSP. The first negative GSP can be equal to or less than about -10 mV / nm. The electron blocking layer EBL can be an organic layer including a compound having the first negative GSP. For example, the compound having the first negative GSP can be compound EBL1, but embodiments are not limited thereto.

[0122]

[0123] The light emitting element ED according to an embodiment includes an electron blocking layer EBL having a first negative GSP equal to or less than about -10 mV / nm, and thus can reduce resistance variation and offset an increase in capacitance caused by an emission layer EML having a positive GSP.

[0124] The hole transport region HTR according to an embodiment can include a hole transport layer HTL. The hole transport layer HTL can be disposed between the electron blocking layer EBL and the hole injection layer HIL. The hole transport layer HTL can include at least one layer. The hole transport layer HTL can have a structure consisting of a single layer including a single material, a structure consisting of a single layer including different materials, or a structure including a plurality of layers containing different materials.

[0125] In an embodiment, the hole transport layer HTL can have a single layer structure consisting of one hole transport material or including a plurality of hole transport materials. For example, the single layer hole transport layer HTL can consist of a first hole transport layer HTL1. In an embodiment, the hole transport layer HTL can have a first hole transport layer HTL1 / second hole transport layer HTL2 structure, or a first hole transport layer HTL1 / second hole transport layer HTL2 / third hole transport layer HTL3 structure, in which the layers of each structure can be stacked in their respective stated order from the hole injection layer HIL. However, embodiments are not limited thereto, and the hole transport layer HTL can have a multi-layer structure including four or more layers.

[0126] The hole transport layer HTL can have a GSP. In an embodiment, when the hole transport layer HTL has a multi-layer structure, the hole transport layer HTL among the layers included in the hole transport layer HTL adjacent to the emission layer EML can have a second negative GSP. However, embodiments are not limited thereto. For example, when the electron transport layer ETL, which will be described later, has a multi-layer structure, and the electron transport layer ETL among the electron transport layers ETL adjacent to the second electrode EL2 has a first positive GSP, the hole transport layer HTL adjacent to the emission layer EML can not have the second negative GSP.

[0127] In an embodiment, a plurality of hole transport layers HTL can be stacked between the first electrode EL1 and the emission layer EML. Among the stack of the hole transport layers HTL, at least one hole transport layer HTL disposed adjacent to the emission layer EML can have a second negative GSP. The second negative GSP can be equal to or less than about -10 mV / nm. In an embodiment, the absolute value of the second negative GSP can not be equal to or greater than the absolute value of the first negative GSP (|second negative GSP| < |first negative GSP|). Thus, the absolute value of the second negative GSP can be less than the absolute value of the above-described first negative GSP.

[0128] Referring to Figure 6 and Figure 8 , the hole transport layer HTL can include a first hole transport layer HTL1 and a second hole transport layer HTL2 disposed between the first electrode EL1 and the emission layer EML. The first hole transport layer HTL1 and the second hole transport layer HTL2 can be sequentially disposed on the first electrode EL1. The first hole transport layer HTL1 can be adjacent to the first electrode EL1, and the second hole transport layer HTL2 can be disposed on the first hole transport layer HTL1 and closer to the emission layer EML than the first hole transport layer HTL1. Among the first hole transport layer HTL1 and the second hole transport layer HTL2, the second hole transport layer HTL2 can have a second negative GSP. For example, among the first hole transport layer HTL1 and the second hole transport layer HTL2, the second hole transport layer HTL2 adjacent to the emission layer EML can have a second negative GSP. The second hole transport layer HTL2 can be an organic layer including a compound having a second negative GSP.

[0129] In Figure 6 and Figure 8In the light-emitting element ED shown in FIG. 1, the first hole-transporting layer HTL1 can be spaced apart from the emission layer EML and positioned closer to the first electrode EL1 than the second hole-transporting layer HTL2. The first hole-transporting layer HTL1 can not have the second negative GSP. The first hole-transporting layer HTL1 can have the second positive GSP or the third negative GSP. The first hole-transporting layer HTL1 can be an organic layer including a compound having the second positive GSP or a compound having the third negative GSP. The third negative GSP can be different from the first negative GSP and the second negative GSP.

[0130] In an embodiment, the second positive GSP can have an absolute value equal to or smaller than about 10 mV / nm (|second positive GSP|≤10 mV / nm), and the third negative GSP can have an absolute value equal to or smaller than about 10 mV / nm (|third negative GSP|≤10 mV / nm). The second positive GSP and the third negative GSP suitable for the first hole-transporting layer HTL1 can each independently have an absolute value equal to or smaller than about 10 mV / nm, but embodiments are not limited thereto.

[0131] In an embodiment, the absolute value of the second positive GSP and the absolute value of the third negative GSP can each be not equal to or not larger than the absolute value of the second negative GSP (|second positive GSP or third negative GSP|<|second negative GSP|). Thus, when the first hole-transporting layer HTL1 has the second positive GSP or the third negative GSP, the second positive GSP and the third negative GSP can each have an absolute value smaller than the absolute value of the second negative GSP. For example, when the first hole-transporting layer HTL1 has the second positive GSP, the absolute value of the second positive GSP of the first hole-transporting layer HTL1 can be smaller than the absolute value of the second negative GSP of the second hole-transporting layer HTL2. For example, when the first hole-transporting layer HTL1 has the third negative GSP, the absolute value of the third negative GSP of the first hole-transporting layer HTL1 can be smaller than the absolute value of the second negative GSP of the second hole-transporting layer HTL2.

[0132] In an embodiment, when the hole-transporting layer HTL includes a plurality of hole-transporting layers, the hole-transporting layer HTL adjacent to the emission layer EML among the hole-transporting layers HTL can not have the second negative GSP. For example, in the light-emitting element ED shown in FIG. 1, the first hole-transporting layer HTL1 can not have the second negative GSP. Figure 8 In the light-emitting element ED shown in FIG. 1, the second hole-transporting layer HTL2 can not have the second negative GSP. In the light-emitting element ED shown in FIG. 1, the second hole-transporting layer HTL2 can have the second positive GSP. Figure 8 In the light-emitting element ED shown in FIG. 1, the electron-transporting layer ETL can have a multi-layer structure, and the second electron-transporting layer ETL2 among the electron-transporting layers ETL1 and ETL2 adjacent to the second electrode EL2 can have the first positive GSP.

[0133] Reference Figure 7The hole transport layer HTL can have a single layer structure. The single layer hole transport layer HTL can be similar to the first hole transport layer HTL1 as described above with reference to Figure 6 and Figure 8

[0134] The hole transport layer HTL having a single layer structure can have a second positive GSP or a third negative GSP. The hole transport layer HTL having a single layer structure can be an organic layer including a compound having a second positive GSP or a compound having a third negative GSP. For example, the absolute value of the second positive GSP can be equal to or less than about 10 mV / nm (|second positive GSP|≤10 mV / nm), and the absolute value of the third negative GSP can be equal to or less than about 10 mV / nm (|third negative GSP|≤10 mV / nm). The second positive GSP and the third negative GSP suitable for the hole transport layer HTL having a single layer structure can each independently have an absolute value equal to or less than about 10 mV / nm, but embodiments are not limited thereto.

[0135] When the hole transport layer HTL included in the light emitting element ED has a single layer structure and the single layer hole transport layer HTL has a second positive GSP or a third negative GSP, the electron transport layer ETL to be described later can have a multi-layer structure. In an embodiment, when the electron transport layer ETL has a multi-layer structure, the electron transport layer ETL adjacent to the second electrode EL2 can have a first positive GSP.

[0136] Referring to Figure 9 , the hole transport layer HTL can have a multi-layer structure including three layers. The hole transport layer HTL can include a first hole transport layer HTL1, a second hole transport layer HTL2, and a third hole transport layer HTL3 disposed between the first electrode EL1 and the emission layer EML. The first hole transport layer HTL1, the second hole transport layer HTL2, and the third hole transport layer HTL3 can be sequentially disposed on the first electrode EL1. Accordingly, the second hole transport layer HTL2 can be positioned closer to the emission layer EML than the first hole transport layer HTL1, and the third hole transport layer HTL3 can be positioned closer to the emission layer EML than the second hole transport layer HTL2. The first hole transport layer HTL1 is spaced apart from the emission layer EML farther than the second hole transport layer HTL2 and the third hole transport layer HTL3, and can be adjacent to the first electrode EL1.

[0137] As described above, in the hole transport layer HTL having a multi-layer structure, the hole transport layer HTL adjacent to the emission layer EML can have a second negative GSP. In an embodiment, the hole transport layer HTL adjacent to the emission layer EML can have a second negative GSP equal to or less than about 10 mV / nm (|second negative GSP|≤10 mV / nm), but embodiments are not limited thereto. Figure 9 ​In the light-emitting element (ED) shown, at least one of the second hole transport layer HTL2 and the third hole transport layer HTL3 adjacent to the emitter layer EML can independently have a second negative GSP. For example, among the first hole transport layer HTL1, the second hole transport layer HTL2, and the third hole transport layer HTL3, the second hole transport layer HTL2 has a second negative GSP, and the first hole transport layer HTL1 and the third hole transport layer HTL3 do not have a second negative GSP. As another example, among the first hole transport layer HTL1, the second hole transport layer HTL2, and the third hole transport layer HTL3, the third hole transport layer HTL3 can have a second negative GSP, and the first hole transport layer HTL1 and the second hole transport layer HTL2 can not have a second negative GSP. The second hole transport layer HTL2 or the third hole transport layer HTL3 can be an organic layer including a compound having a second negative GSP.

[0138] exist Figure 9 In the light-emitting element (ED) shown, among the first hole transport layer HTL1, the second hole transport layer HTL2, and the third hole transport layer HTL3, the first hole transport layer HTL1 may be spaced apart from the emitter layer EML and positioned adjacent to the first electrode EL1. The first hole transport layer HTL1 may not have a second negative GSP. In an embodiment, the first hole transport layer HTL1 may have a third positive GSP or a fourth negative GSP. In an embodiment, among the second hole transport layer HTL2 and the third hole transport layer HTL3, the layer without a second negative GSP may have a third positive GSP or a fourth negative GSP.

[0139] For example, the second hole transport layer HTL2 may have a second negative GSP. Therefore, the first hole transport layer HTL1 and the third hole transport layer HTL3 may not have a second negative GSP. In embodiments, the first hole transport layer HTL1 and the third hole transport layer HTL3 may each independently have a third positive GSP or a fourth negative GSP. The first hole transport layer HTL1 and the third hole transport layer HTL3 may each be an organic layer comprising a compound having a third positive GSP or a compound having a fourth negative GSP. The GSP of the first hole transport layer HTL1 and the GSP of the third hole transport layer HTL3 may be the same as or different from each other.

[0140] For example, the third hole transport layer HTL3 can have a second negative GSP, and the first hole transport layer HTL1 and the second hole transport layer HTL2 can not have the second negative GSP. The first hole transport layer HTL1 and the second hole transport layer HTL2 not having the second negative GSP can each independently have a third positive GSP or a fourth negative GSP. The first hole transport layer HTL1 and the second hole transport layer HTL2 can each be an organic layer including a compound having the third positive GSP or a compound having the fourth negative GSP. The GSP of the first hole transport layer HTL1 and the GSP of the second hole transport layer HTL2 can be the same as or different from each other.

[0141] In an embodiment, an absolute value of the third positive GSP can be equal to or less than about 10 mV / nm (|third positive GSP|≤10 mV / nm), and an absolute value of the fourth negative GSP can be equal to or less than about 10 mV / nm (|fourth negative GSP|≤10 mV / nm). The absolute value of the third positive GSP and the absolute value of the fourth negative GSP can each independently be equal to or less than about 10 mV / nm, but embodiments are not limited thereto.

[0142] In an embodiment, an absolute value of the third positive GSP can be not equal to or not greater than an absolute value of the second negative GSP (|third positive GSP|<|second negative GSP|), and an absolute value of the fourth negative GSP can be not equal to or not greater than the absolute value of the second negative GSP (|fourth negative GSP|<|second negative GSP|). Accordingly, the absolute value of the third positive GSP and the absolute value of the fourth negative GSP of the first hole transport layer HTL1 can each be less than the absolute value of the second negative GSP of the second hole transport layer HTL2 or the third hole transport layer HTL3. In an embodiment, the absolute value of the third positive GSP and the absolute value of the fourth negative GSP of the second hole transport layer HTL2 or the third hole transport layer HTL3 can each be less than the absolute value of the second negative GSP of the first hole transport layer HTL1.

[0143] For example, when the first hole transport layer HTL1 has the third positive GSP, the absolute value of the third positive GSP of the first hole transport layer HTL1 can be less than the absolute value of the second negative GSP of the second hole transport layer HTL2 or the third hole transport layer HTL3. For example, when the first hole transport layer HTL1 has the fourth negative GSP, the absolute value of the fourth negative GSP of the first hole transport layer HTL1 can be less than the absolute value of the second negative GSP of the second hole transport layer HTL2 or the third hole transport layer HTL3.

[0144] In an embodiment, when the second hole-transport layer HTL2 has a third positive GSP and the third hole-transport layer HTL3 has a second negative GSP, the absolute value of the third positive GSP of the second hole-transport layer HTL2 can be smaller than the absolute value of the second negative GSP of the third hole-transport layer HTL3. In an embodiment, when the second hole-transport layer HTL2 has a fourth negative GSP and the third hole-transport layer HTL3 has a second negative GSP, the absolute value of the fourth negative GSP of the second hole-transport layer HTL2 can be smaller than the absolute value of the second negative GSP of the third hole-transport layer HTL3. When the third hole-transport layer HTL3 has a third positive GSP and the second hole-transport layer HTL2 has a second negative GSP, the absolute value of the third positive GSP of the third hole-transport layer HTL3 can be smaller than the absolute value of the second negative GSP of the second hole-transport layer HTL2. When the third hole-transport layer HTL3 has a fourth negative GSP and the second hole-transport layer HTL2 has a second negative GSP, the absolute value of the fourth negative GSP of the third hole-transport layer HTL3 can be smaller than the absolute value of the second negative GSP of the second hole-transport layer HTL2.

[0145] In an embodiment, among the first hole-transport layer HTL1, the second hole-transport layer HTL2, and the third hole-transport layer HTL3, at least one of the second hole-transport layer HTL2 and the third hole-transport layer HTL3 adjacent to the emission layer EML can not have a second negative GSP. For example, in the light-emitting element ED illustrated in FIG. 1B, the second hole-transport layer HTL2 and / or the third hole-transport layer HTL3 can not have a second negative GSP. Thus, as illustrated in FIG. 1B, the second hole-transport layer HTL2 and / or the third hole-transport layer HTL3 can have a first positive GSP. Figure 9 In the light-emitting element ED illustrated in FIG. 1B, the second hole-transport layer HTL2 and / or the third hole-transport layer HTL3 can not have a second negative GSP. Thus, as illustrated in FIG. 1B, the second hole-transport layer HTL2 and / or the third hole-transport layer HTL3 can have a first positive GSP. Figure 9 In the light-emitting element ED illustrated in FIG. 1B, the second hole-transport layer HTL2 and / or the third hole-transport layer HTL3 can not have a second negative GSP. Thus, as illustrated in FIG. 1B, the second hole-transport layer HTL2 and / or the third hole-transport layer HTL3 can have a first positive GSP.

[0146] In the light-emitting element ED according to an embodiment, the hole-transport region HTR can include a compound represented by Formula H-1:

[0147] [Formula H-1]

[0148]

[0149] In Formula H-1, L1and L2may each independently be a direct bond, a substituted or unsubstituted arylene group with 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group with 2 to 30 ring-forming carbon atoms. In Formula H-1, a and b can each independently be an integer of 0 to 10. When a or b is 2 or more, the plurality of L1or the plurality of L2may each independently be a substituted or unsubstituted arylene group with 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group with 2 to 30 ring-forming carbon atoms.

[0150] In Formula H-1, Ar1and Ar2may each independently be a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. In Formula H-1, Ar3may be a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.

[0151] In an embodiment, the compound represented by Formula H-1 can be a monoamine compound. In another embodiment, the compound represented by Formula H-1 can be a diamine compound in which at least one of Ar1to Ar3includes an amine group as a substituent. In an embodiment, the compound represented by Formula H-1 can be a carbazole-based compound in which at least one of Ar1and Ar2includes a substituted or unsubstituted carbazolyl group, or can be a fluorene-based compound in which at least one of Ar1and Ar2includes a substituted or unsubstituted fluorenyl group.

[0152] The compound represented by Formula H-1 can be any compound selected from Compound Group H. However, the compounds listed in Compound Group H are merely examples, and the compound represented by Formula H-1 is not limited to Compound Group H:

[0153] [Compound Group H]

[0154]

[0155]

[0156] The hole transport region HTR can 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- 4,4',4"-tris(N,N-diphenylamino)triphenylamine (TDATA), - 4,4',4"-tris[N-(2-naphthyl)-N-phenylamino]-triphenylamine (2-TNATA), - poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), - polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), - polyaniline / camphor sulfonic acid (PANI / CSA), - polyaniline / poly(4-styrenesulfonate) (PANI / PSS), - N,N'-bis(naphthalen-1-yl)-N,N'-diphenyl-benzidine (NPB), - triphenylamine-containing polyether ketone (TPAPEK), - 4-isopropyl-4'-methyl diphenyl iodonium [tetrakis(pentafluorophenyl)borate], - dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN), and the like.

[0157] The hole transport region HTR can include: a carbazole derivative such as N-phenylcarbazole or polyvinylcarbazole; a fluorene derivative; a triphenylamine derivative such as N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1-biphenyl]-4,4'-diamine (TDN) or 4,4',4"-tris(N-carbazolyl)triphenylamine (TCTA); N,N'-bis(naphthalen-1-yl)-N,N'-diphenyl-benzidine (NPB); 4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine] (TAPC); 4,4'-bis[N,N'-(3-methylphenyl)amino]-3,3'-dimethylbiphenyl (HMTPD); 1,3-bis(H-carbazolyl)benzene (mCP); and the like.

[0158] In an embodiment, the hole transport region HTR can include 9-(4-tert-butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole (CzSi), 9-phenyl-9H-3,9'-bicarbazole (CCP), 1,3-bis(1,8-dimethyl-9H-carbazol-9-yl)benzene (mDCP), and the like.

[0159] The hole transport region HTR can include the above-described compounds of the hole transport region in at least one of the hole injection layer HIL, the hole transport layer HTL, and the electron blocking layer EBL.

[0160] In addition to the materials described above, the hole transport region (HTR) may also include a charge-generating material to increase conductivity. The charge-generating material may be uniformly or non-uniformly dispersed in the hole transport region (HTR). The charge-generating material may be, for example, a p-dopant. The p-dopant may include at least one of metal halides, quinone derivatives, metal oxides, and cyano-containing compounds, but the embodiments are not limited thereto. For example, p-dopers may include: metal halides, such as CuI or RbI; quinone derivatives, such as tetracyanoquinone dimethyl ether (TCNQ) or 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinone dimethyl ether (F4-TCNQ); metal oxides, such as tungsten oxide or molybdenum oxide; cyano-containing compounds, such as dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexaonitrile (HAT-CN) or 4-[[2,3-bis[cyano-(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropylidene]-cyanomethyl]-2,3,5,6-tetrafluorobenzonitrile (NDP9), etc., but the examples are not limited thereto.

[0161] As described above, in addition to the hole injection layer HIL, hole transport layer HTL, and electron blocking layer EBL, the hole transport region HTR may also include a buffer layer (not shown). The buffer layer (not shown) can compensate for the resonant distance according to the wavelength of the light emitted from the emission layer EML, and thus can increase the light emission efficiency. The material that can be included in the hole transport region HTR can be used as the material in the buffer layer (not shown).

[0162] The emitter layer EML can provide coverage on the hole transport region HTR. The emitter layer EML can have approximately... up to approximately The thickness can be within a certain range. For example, the emitter layer EML can have a thickness of approximately... up to approximately The thickness is within a certain range. The emitter layer (EML) can have a structure consisting of a single layer of a single material, a structure consisting of single layers of different materials, or a structure consisting of multiple layers containing different materials.

[0163] In an embodiment, the emitter layer EML may have a positive gas-spike junction (GSP). This prevents an increase in the device drive voltage. For example, the emitter layer EML may have a fourth positive GSP. The fourth positive GSP may be equal to or greater than approximately 10 mV / nm. The emitter layer EML may be an organic layer comprising a compound having a fourth positive GSP.

[0164] In the light-emitting element ED, the emission layer EML can emit blue light. For example, the emission layer EML of the light-emitting element ED can emit blue light in a wavelength range equal to or smaller than approximately 490 nm. However, embodiments are not limited thereto, and the emission layer EML can emit green light or red light.

[0165] In the light-emitting element ED, the emission layer EML can include an anthracene derivative, a pyrene derivative, a fluoranthene derivative, For example, the emission layer EML can include an anthracene derivative or a pyrene derivative.

[0166] In the light-emitting element ED according to embodiments as illustrated in Figures 3 to 10 In the light-emitting element ED according to embodiments as illustrated in

[0167] [Formula E-1]

[0168]

[0169] In Formula E-1, R 31 to R 40 may each independently be a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted silyl group, a substituted or unsubstituted sulfo group, a substituted or unsubstituted oxy group, a substituted or unsubstituted alkyl group with 1 to 10 carbon atoms, a substituted or unsubstituted alkenyl group with 2 to 10 carbon atoms, a substituted or unsubstituted aryl group with 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group with 2 to 30 ring-forming carbon atoms, or be bonded to an adjacent group to form a ring. For example, R 31 to R 40 may be bonded to an adjacent group to form a saturated hydrocarbon ring, an unsaturated hydrocarbon ring, a saturated heterocyclic ring, or an unsaturated heterocyclic ring.

[0170] In Formula E-1, c and d can each independently be an integer of 0 to 5.

[0171] In embodiments, the compound represented by Formula E-1 can be any compound selected from Compound E1 to Compound E19:

[0172]

[0173]

[0174]

[0175] In an embodiment, the emission layer EML can include a hole transport host compound represented by Formula HT-1:

[0176] [Formula HT-1]

[0177]

[0178] In Formula HT-1, A1to A8may each independently be N or C(R 51 ). For example, A1to A8may each independently be C(R 51 ). As another example, one of A1to A8may be N, and the remaining groups of A1to A8may each independently be C(R 51 ).

[0179] In Formula HT-1, L1may be a direct bond, a substituted or unsubstituted arylene having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene having 2 to 30 ring-forming carbon atoms. For example, L1may be a direct bond, a substituted or unsubstituted phenylene, a substituted or unsubstituted divalent biphenyl group, a substituted or unsubstituted divalent carbazolyl group, or the like, but embodiments are not limited thereto.

[0180] In Formula HT-1, Y a may be a direct bond, C(R 52 )(R 53 ), or Si(R 54 )(R 55 ). For example, the two rings connected to the nitrogen atom in Formula HT-1may be connected to each other by a direct bond, In Formula HT-1, when Y a is a direct bond, the compound represented by Formula HT-1may include a carbazole moiety.

[0181] In Formula HT-1, Ar1may be a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. For example, Ar1may be a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted biphenyl group, or the like, but embodiments are not limited thereto.

[0182] In Formula HT-1, R 51 to R 55may each independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted silyl group, a substituted or unsubstituted sulfonyl group, a substituted or unsubstituted oxyl group, a substituted or unsubstituted aminyl group, a substituted or unsubstituted boron group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 60 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 60 ring-forming carbon atoms, or be bonded to an adjacent group to form a ring. For example, R 51 to R 55 may each independently be a hydrogen atom or a deuterium atom. For example, R 51 to R 55 may each independently be an unsubstituted methyl group or an unsubstituted phenyl group.

[0183] In an embodiment, the hole transport host represented by Formula HT-1 can be selected from the group of compounds HT. In an embodiment, in the light-emitting element ED, the hole transport host can include at least one compound selected from the group of compounds HT.

[0184] [Group of Compounds HT]

[0185]

[0186]

[0187]

[0188] In the group of compounds HT, D represents a deuterium atom, and Ph represents a substituted or unsubstituted phenyl group. For example, in the group of compounds HT, Ph can represent an unsubstituted phenyl group.

[0189] In an embodiment, the emission layer EML can include an electron transport host compound represented by Formula ET-1:

[0190] [Formula ET-1]

[0191]

[0192] In Formula ET-1, at least one of X1to X3may each be N, and the remaining groups of X1to X3may each independently be C(R 56 ). For example, one of X1to X3may be N, and the remaining groups of X1to X3may each independently be C(R 56 ). Thus, the compound represented by Formula ET-1may include a pyridine moiety. As another example, two of X1to X3may each be N, and the remaining groups of X1to X3may each independently be C(R 56). Thus, the compound represented by Formula ET-1 can include a pyrimidine moiety. As still another example, X1to X3may each be N. Thus, the compound represented by Formula ET-1 can include a triazine moiety.

[0193] In Formula ET-1, R 56 may be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 60 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 60 ring-forming carbon atoms.

[0194] In Formula ET-1, b1to b3may each independently be an integer of 0 to 10.

[0195] In Formula ET-1, Ar2to Ar4may each independently be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. For example, Ar2to Ar4may each independently be a substituted or unsubstituted phenyl group, or a substituted or unsubstituted carbazolyl group.

[0196] In Formula ET-1, L2to L4may each independently be a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. When b1to b3are each 2 or more, L2to L4may each independently be a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms.

[0197] In an embodiment, the electron-transporting host represented by Formula ET-1may be selected from Compound Group ET. In an embodiment, in the light-emitting element ED, the electron-transporting host can include at least one compound selected from Compound Group ET.

[0198] [Compound Group ET]

[0199]

[0200]

[0201]

[0202] In Compound Group ET, D represents a deuterium atom, and Ph represents an unsubstituted phenyl group.

[0203] The emission layer EML can include a hole transport host and an electron transport host, and the hole transport host and the electron transport host can form an exciplex. A triplet energy level of the exciplex formed by the hole transport host and the electron transport host can correspond to a difference between a lowest unoccupied molecular orbital (LUMO) energy level of the electron transport host and a highest occupied molecular orbital (HOMO) energy level of the hole transport host.

[0204] For example, an absolute value of a triplet energy level (T1) of the exciplex formed by the hole transport host and the electron transport host can be in a range of about 2.4 eV to about 3.0 eV. The triplet energy of the exciplex can be a value less than a band gap of each of the host materials. The triplet energy level of the exciplex can be equal to or less than about 3.0 eV, which is a band gap between the hole transport host and the electron transport host.

[0205] In an embodiment, the emission layer EML can include a compound represented by Formula E-2a or Formula E-2b. The compound represented by Formula E-2a or Formula E-2b can be used as a phosphorescent host material.

[0206] [Formula E-2a]

[0207]

[0208] In Formula E-2a, a can be an integer of 0 to 10; and L a may be a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. When a is 2 or more, the plurality of L a can each independently be a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms.

[0209] In Formula E-2a, A1 to A5 can each independently be N or C(R i ). In Formula E-2a, R a to R i may each independently be a hydrogen atom, a deuterium atom, a substituted or unsubstituted amine group, a substituted or unsubstituted sulfide group, a substituted or unsubstituted oxygen group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or be bonded to an adjacent group to form a ring. For example, R a to R i may be bonded to an adjacent group to form a hydrocarbon ring or a heterocycle including N, O, S, etc. as a ring-forming atom.

[0210] In Formula E-2a, two or three of A1to A5may each be N, and the remaining groups of A1to A5may each independently be C(R i ).

[0211] [Formula E-2b]

[0212]

[0213] In Formula E-2b, Cbz1and Cbz2may each independently be unsubstituted carbazolyl, or carbazolyl substituted with aryl having 6 to 30 ring-forming carbon atoms. In Formula E-2b, L b is a direct bond, substituted or unsubstituted arylene having 6 to 30 ring-forming carbon atoms, or substituted or unsubstituted heteroarylene having 2 to 30 ring-forming carbon atoms. In Formula E-2b, b can be an integer of 0 to 10. When b is 2 or more, the multiple L b may each independently be substituted or unsubstituted arylene having 6 to 30 ring-forming carbon atoms, or substituted or unsubstituted heteroarylene having 2 to 30 ring-forming carbon atoms.

[0214] In embodiments, the compound represented by Formula E-2a or Formula E-2b can be any compound selected from Compound Group E-2. However, the compounds listed in Compound Group E-2 are merely examples, and the compound represented by Formula E-2a or Formula E-2b is not limited to the compounds of Compound Group E-2:

[0215] [Compound Group E-2]

[0216]

[0217]

[0218] In an embodiment, the emission layer EML can further include a material of a related art as a host material. The emission layer EML can include at least one of bis(4-(9H-carbazol-9-yl)phenyl)diphenylsilane (BCPDS), (4-(1-(4-(diphenylamino)phenyl)cyclohexyl)phenyl)diphenyl-phosphine oxide (POPCPA), bis[2-(diphenylphosphino)phenyl]ether oxide (DPEPO), 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP), 1,3-bis(carbazol-9-yl)benzene (mCP), 2,8-bis(diphenylphosphoryl)dibenzo[b,d]furan (PPF), 4,4',4"-tris(carbazol-9-yl)-triphenylamine (TCTA), and 1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene (TPBi) as the host material. However, embodiments are not limited thereto. For example, tris(8-hydroxyquinoline)aluminum (Alq3), 9,10-di(naphthalen-2-yl)anthracene (ADN), 2-tert-butyl-9,10-di(naphthalen-2-yl)anthracene (TBADN), distyrylbenzene (DSA), 4,4'-bis(9-carbazolyl)-2,2'-dimethyl-biphenyl (CDBP), 2-methyl-9,10-di(naphthalen-2-yl)anthracene (MADN), hexaphenylcyclotrisilazane (CP1), 1,4-bis(triphenylsilyl)benzene (UGH2), hexaphenylcyclotrisiloxane (DPSiO3), octaphenylcyclotetrasiloxane (DPSiO4), or the like can be used as the host material.

[0219] In an embodiment, the emission layer EML can include a compound represented by Formula M-a or Formula M-b. The compound represented by Formula M-a or Formula M-b can be used as a phosphorescent dopant material.

[0220] [Formula M-a]

[0221]

[0222] In Formula M-a, Y1 to Y4 and Z1 to Z4 can each independently be C(R1) or N; and R1 to R4 can each independently be a hydrogen atom, a deuterium atom, a substituted or unsubstituted amine group, a substituted or unsubstituted sulfur group, a substituted or unsubstituted oxygen group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or be bonded to an adjacent group to form a ring. In Formula M-a, m can be 0 or 1, and n can be 2 or 3. In Formula M-a, when m is 0, n can be 3, and when m is 1, n can be 2.

[0223] In an embodiment, the compound represented by Formula M-a can be any compound selected from the group consisting of Compound M-a1 to Compound M-a25. However, the compounds M-a1 to M-a25 are merely examples, and the compound represented by Formula M-a is not limited to the compounds M-a1 to M-a25:

[0224]

[0225]

[0226] Compound M-a1 and Compound M-a2 can each be used as a red dopant material, and Compound M-a3 to Compound M-a7 can each be used as a green dopant material.

[0227] [Formula M-b]

[0228]

[0229] In Formula M-b, Q1 to Q4 can each independently be C or N; and C1 to C4 can each independently be a substituted or unsubstituted hydrocarbon ring having 5 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heterocyclic ring having 2 to 30 ring-forming carbon atoms.

[0230] In Formula M-b, L 21 to L 24 may each independently be a direct bond, *-O-*, *-S-*, *-N(Rf)-*, a substituted or unsubstituted alkylene having 1 to 20 carbon atoms, a substituted or unsubstituted arylene having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene having 2 to 30 ring-forming carbon atoms; and e1 to e4 can each independently be 0 or 1.

[0231] In Formula M-b, R 31 to R 39 may each independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or bonded to an adjacent group to form a ring; and d1 to d4 can each independently be an integer of 0 to 4.

[0232] The compound represented by Formula M-b can be used as a blue phosphorescent dopant or a green phosphorescent dopant. In an embodiment, the compound represented by Formula M-b can also be included in the emission layer EML as an auxiliary dopant.

[0233] In an embodiment, the compound represented by Formula M-b can be any compound selected from the group consisting of Compound M-b-1 to Compound M-b-12. However, Compound M-b-1 to Compound M-b-12 are merely examples, and the compound represented by Formula M-b is not limited to Compound M-b-1 to Compound M-b-12:

[0234] In Compound M-b-1 to Compound M-b-12, R, R 38 and R 39 may each independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.

[0235] In an embodiment, the emission layer EML can further include a compound represented by one of Formula F-a to Formula F-c. The compound represented by one of Formula F-a to Formula F-c can be used as a fluorescent dopant material.

[0236] [Formula F-a]

[0237]

[0238] In Formula F-a, R a to R j may each independently be substituted with a group represented by *-NAr1Ar2. The remaining groups among R a to R j that are not substituted with a group represented by *-NAr1Ar2may each independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.

[0239] In the group represented by *-NAr1Ar2, Ar1and Ar2may each independently be a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. For example, at least one of Ar1and Ar2may each independently be a heteroaryl group including O or S as a ring-forming atom.

[0240] [Formula F-b]

[0241]

[0242] In Formula F-b, Ra and R b may each independently be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or bonded to an adjacent group to form a ring. In Formula F-b, Ar1to Ar4may each independently be a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. For example, at least one of Ar1to Ar4may each independently be a heteroaryl group including O or S as a ring-forming atom.

[0243] In Formula F-b, U and V may each independently be a substituted or unsubstituted hydrocarbon ring having 5 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heterocycle having 2 to 30 ring-forming carbon atoms.

[0244] In Formula F-b, the number of rings represented by U and V (hereinafter, simply referred to as the number of U, the number of V) may each independently be 0 or 1. When the number of U or V is 1, a fused ring can be present at the portion indicated by U or V, respectively, and when the number of U or V is 0, a fused ring can be absent at the portion indicated by U or V, respectively. When the number of U is 0 and the number of V is 1, or when the number of U is 1 and the number of V is 0, the fused ring of the fluorene core having Formula F-b can be a cyclic compound having four rings. When the number of U and V is each 0, the fused ring of the fluorene core having Formula F-b can be a cyclic compound having three rings. When the number of U and V is each 1, the fused ring of the fluorene core having Formula F-b can be a cyclic compound having five rings.

[0245] [Formula F-c]

[0246]

[0247] In Formula F-c, A1and A2may each independently be O, S, Se, or N(R m ); and R m may be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. In Formula F-c, R1to R 11may each independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted boron group, a substituted or unsubstituted oxygen group, a substituted or unsubstituted sulfur group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or bonded to an adjacent group to form a ring.

[0248] In Formula F-c, A1and A2may each independently be bonded to a substituent of an adjacent ring to form a fused ring. For example, when A1and A2are each independently N(R m )A1may be bonded to R4or R5to form a fused ring, and / or A2may be bonded to R7or R8to form a fused ring.

[0249] In an embodiment, the emission layer EML can further include a styryl derivative (e.g., 1,4-bis[2-(3-N-ethylcarbazolyl)vinyl]benzene (BCzVB), 4-(di-p-tolylamino)-4'-[(di-p-tolylamino)styryl]stilbene (DPAVB), N-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl)naphthalen-2-yl)vinyl)phenyl)-N-phenylbenzenamine (N-BDAVBi), and 4,4'-bis[2-(4-(N,N-diphenylamino)phenyl)vinyl]biphenyl (DPAVBi)), perylene or a derivative thereof (e.g., 2,5,8,11-tetra-tert-butylperylene (TBP)), pyrene or a derivative thereof (e.g., 1,1'-dipyrene, 1,4-dipyrenylbenzene, and 1,4-bis(N,N-diphenylamino)pyrene), etc., which are a dopant material of a related art.

[0250] The emission layer EML can further include a phosphorescent dopant material of a related art. For example, a metal complex including iridium (Ir), platinum (Pt), osmium (Os), gold (Au), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), or thulium (Tm) can be used as a phosphorescent dopant. For example, bis(4,6-difluorophenylpyridine-N,C2')picolatohridium(III) (FIrpic), bis(2,4-difluorophenylpyridine)-tetra(1-pyrazolyl)borate iridium(III) (FIr6), or platinum octaethylporphyrin (PtOEP) can be used as a phosphorescent dopant. However, embodiments are not limited thereto.

[0251] As described above, the emission layer EML can include a hole transport host and an electron transport host. In an embodiment, the emission layer EML can further include an auxiliary dopant and an emission dopant. The auxiliary dopant can include a phosphorescent dopant material or a thermally activated delayed fluorescent dopant material. For example, in an embodiment, the emission layer EML can include a hole transport host, an electron transport host, an auxiliary dopant, and an emission dopant.

[0252] In an embodiment, the emission layer EML can include a quantum dot. In the specification, a quantum dot can be a crystal of a semiconductor compound. Depending on the size of the crystal, a quantum dot can emit light of various emission wavelengths. A quantum dot can also emit light of various emission wavelengths by adjusting the element ratio of a quantum dot compound. The diameter of a quantum dot can be, for example, in a range of about 1 nm to about 10 nm, but embodiments are not limited thereto.

[0253] A quantum dot can be synthesized by a wet chemical process, an organometallic vapor deposition process, a molecular beam epitaxy process, or any similar process. The wet chemical process is a method of growing quantum dot particles crystals in which an organic solvent and a precursor material are mixed together. The organic solvent naturally serves as a dispersant coordinated to the surface of the quantum dot crystal as the crystal grows, and the growth of the crystal can be controlled. Accordingly, the wet chemical process can be more easily performed than a vapor deposition method such as metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE), and the growth of quantum dot particles can be controlled by a low-cost process.

[0254] A quantum dot can include a group II-VI compound, a group III-V compound, a group III-VI compound, a group I-III-VI compound, a group IV-VI compound, a group IV element, a group IV compound, or a combination thereof.

[0255] Examples of Group II-VI compounds can include binary compounds such as CdSe, CdTe, CdS, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, and mixtures thereof; ternary compounds such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, and mixtures thereof; quaternary compounds such as CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, and mixtures thereof; and any combination thereof. In embodiments, Group II-VI compounds can also include Group I metals and / or Group IV elements. Examples of Group I-II-VI compounds can include CuZnS; and examples of Group II-IV-VI compounds can include ZnSnS, etc. Examples of Group I-II-IV-VI compounds can include quaternary compounds such as Cu2ZnSnS2, Cu2ZnSnS4, Cu2ZnSnSe4, Ag2ZnSnS2, and mixtures thereof.

[0256] Examples of Group III-VI compounds can include binary compounds such as In2S3and In2Se3; ternary compounds such as InGaS3and InGaSe3; and any combination thereof.

[0257] Examples of Group I-III-VI compounds can include ternary compounds such as AgInS, AgInS2, CuInS, CuInS2, AgGaS2, CuGaS2, CuGaO2, AgGaO2, AgAlO2, and mixtures thereof; quaternary compounds such as AgInGaS2and CuInGaS2; and any combination thereof.

[0258] Examples of III-V compounds can include binary compounds such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and mixtures thereof; ternary compounds such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InAlP, InNP, InNAs, InNSb, InPAs, InPSb, and mixtures thereof; quaternary compounds such as GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and mixtures thereof; and any combination thereof. In embodiments, the III-V compound can also include a Group II metal. Examples of III- II-V compounds can include InZnP, etc.

[0259] Examples of IV-VI compounds can include binary compounds such as SnS, SnSe, SnTe, PbS, PbSe, PbTe, and mixtures thereof; ternary compounds such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and mixtures thereof; quaternary compounds such as SnPbSSe, SnPbSeTe, SnPbSTe, and mixtures thereof; and any combination thereof.

[0260] Examples of II-IV-V compounds can include ternary compounds such as ZnSnP, ZnSnP2, ZnSnAs2, ZnGeP2, ZnGeAs2, CdSnP2, CdGeP2, and mixtures thereof.

[0261] Examples of Group IV elements can include Si, Ge, and mixtures thereof. Examples of Group IV compounds can include binary compounds such as SiC, SiGe, and mixtures thereof.

[0262] Each element included in a compound such as a binary compound, a ternary compound, or a quaternary compound can be present in the particle in a uniform concentration distribution or in a non-uniform concentration distribution. For example, a formula can indicate elements included in a compound, but the elemental proportions of the compound can vary. For example, AgInGaS2may indicate AgIn x Ga 1-x S2(where x is a real number between 0 and 1).

[0263] In an embodiment, the quantum dot can have a core-shell structure in which the quantum dot surrounds another quantum dot. The quantum dot having the core-shell structure can have a concentration gradient in which the concentration of an element present in the shell decreases toward the core.

[0264] In an embodiment, the quantum dot can have the above-described core-shell structure including a core including a nanocrystal and a shell surrounding the core. The shell of the quantum dot can serve as a protective layer that prevents chemical denaturation of the core to maintain a semiconductor property, and / or can serve as a charging layer that imparts an electrophoretic property to the quantum dot. The shell can be single-layered or multi-layered. Examples of the shell of the quantum dot can include a metal oxide, a non-metal oxide, a semiconductor compound, and combinations thereof.

[0265] Examples of the metal oxide or the non-metal oxide can include binary compounds such as SiO2, Al2O3, TiO2, ZnO, MnO, Mn2O3, Mn3O4, CuO, FeO, Fe2O3, Fe3O4, CoO, Co3O4, and NiO; ternary compounds such as MgAl2O4, CoFe2O4, NiFe2O4, and CoMn2O4; and any combinations thereof, but embodiments are not limited thereto.

[0266] Examples of the semiconductor compound can include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, etc., but embodiments are not limited thereto.

[0267] The quantum dot can have a full width at half maximum (FWHM) of an emission wavelength spectrum equal to or less than about 45 nm. For example, the quantum dot can have a FWHM of the emission wavelength spectrum equal to or less than about 40 nm. For example, the quantum dot can have a FWHM of the emission wavelength spectrum equal to or less than about 30 nm. In any of the above ranges, color purity or color reproducibility can be improved. Light emitted by the quantum dot can be emitted in all directions, so that a wide viewing angle can be improved.

[0268] The form / shape of the quantum dot is not particularly limited and can be any form / shape used in the related art. For example, the quantum dot can have a spherical shape, a pyramid shape, a multi-arm shape, or a cubic shape, or the quantum dot can be in the form of a nanoparticle, a nanotube, a nanowire, a nanofiber, a nanoplate, etc.

[0269] When the size of the quantum dot is adjusted or the element ratio of the quantum dot compound is adjusted, the energy band gap can be controlled accordingly, and thus light in various wavelength ranges can be obtained from the quantum dot emission layer. Accordingly, by utilizing quantum dots as described in this document (using quantum dots of different sizes or having different element ratios in the quantum dot compound), light-emitting elements that emit light in various wavelength ranges can be implemented. For example, the size of the quantum dot can be adjusted or the element ratio of the quantum dot compound can be adjusted to emit red light, green light, and / or blue light. In an embodiment, the quantum dot can be configured to emit white light by combining light of various colors.

[0270] In the light-emitting element ED according to the embodiment as shown in Figures 3 to 10 , an electron transport region ETR can be provided on the emission layer EML. The electron transport region ETR can include at least one of a hole blocking layer HBL, an electron transport layer ETL, and an electron injection layer EIL, but embodiments are not limited thereto.

[0271] The electron transport region ETR can have a structure composed of a single layer including a single material, a structure composed of a single layer including different materials, or a structure including a plurality of layers containing different materials.

[0272] For example, the electron transport region ETR can have a single layer structure composed of the electron injection layer EIL or the electron transport layer ETL, or can have a single layer structure formed of an electron injection material and an electron transport material. The electron transport region ETR can have a single layer structure formed of different materials. In an embodiment, the electron transport region ETR can have an electron transport layer ETL / electron injection layer EIL structure, or a hole blocking layer HBL / electron transport layer ETL / electron injection layer EIL structure, in which the layers of each structure are stacked in their respective stated order from the emission layer EML, but embodiments are not limited thereto. The electron transport region ETR can have a thickness in the range of, for example, about to about .

[0273] The electron transport region ETR can be formed using various methods such as a vacuum deposition method, a spin coating method, a casting method, a Langmuir-Blodgett (LB) method, an inkjet printing method, a laser printing method, and a laser-induced thermal imaging (LITI) method.

[0274] The electron transport layer ETL can be disposed between the emission layer EML and the electron injection layer EIL. The electron transport layer ETL can include at least one layer. The electron transport layer ETL can have a structure composed of a single layer including a single material, a structure composed of a single layer including different materials, or a structure including a plurality of layers containing different materials.

[0275] In an embodiment, the electron transport layer ETL can have a single layer structure. For example, the electron transport layer ETL having a single layer structure can consist of one electron transport material or can include a plurality of electron transport materials. For example, the electron transport layer ETL having a single layer structure can consist of a first electron transport layer ETL1. In an embodiment, the electron transport layer ETL can have a first electron transport layer ETL1 / second electron transport layer ETL2 structure, or a first electron transport layer ETL1 / second electron transport layer ETL2 / third electron transport layer ETL3 structure, in which the layers of each structure can be stacked in the order of their respective recitations from the emission layer EML. However, embodiments are not limited thereto, and the electron transport layer ETL can have a multi-layer structure including four or more layers.

[0276] The electron transport layer ETL having a single layer structure can have a fifth positive GSP or a fifth negative GSP. The electron transport layer ETL having a single layer structure can be an organic layer including a compound having a fifth positive GSP or a compound having a fifth negative GSP. For example, the absolute value of the fifth positive GSP can be equal to or less than about 10 mV / nm (|fifth positive GSP|≤10 mV / nm), and the absolute value of the fifth negative GSP can be equal to or less than about 10 mV / nm (|fifth negative GSP|≤10 mV / nm). The fifth positive GSP and the fifth negative GSP suitable for the hole transport layer HTL having a single layer structure can each independently have an absolute value equal to or less than about 10 mV / nm, but embodiments are not limited thereto.

[0277] When the electron transport layer ETL has a single layer structure and the single layer of the electron transport layer ETL has a fifth positive GSP or a fifth negative GSP, the hole transport layer HTL can have a multi-layer structure. In an embodiment, when the hole transport layer HTL has a multi-layer structure, the hole transport layer HTL adjacent to the emission layer EML can have a second negative GSP.

[0278] In an embodiment, when the electron transport layer ETL has a multi-layer structure, the electron transport layer ETL including a layer among the layers of the electron transport layer ETL adjacent to the second electrode EL2 (e.g., a cathode) can have a first positive GSP. However, embodiments are not limited thereto. For example, when the hole transport layer HTL has a multi-layer structure, and the hole transport layer HTL among the hole transport layers HTL adjacent to the emission layer EML has a second negative GSP, the electron transport layer ETL adjacent to the second electrode EL2 can not have a first positive GSP.

[0279] In an embodiment, a plurality of electron transport layers ETL can be stacked between the emission layer EML and the second electrode EL2. Among the stack of electron transport layers ETL, at least one electron transport layer ETL disposed adjacent to the second electrode EL2 can have a first positive GSP. The first positive GSP can be equal to or greater than about 10 mV / nm. For example, the first positive GSP can be in a range of about 10 mV / nm to about 50 mV / nm, but embodiments are not limited thereto.

[0280] Referring to Figure 7 and Figure 8 , the electron transport layer ETL can include a first electron transport layer ETL1 and a second electron transport layer ETL2 disposed between the emission layer EML and the second electrode EL2. The first electron transport layer ETL1 and the second electron transport layer ETL2 can be sequentially disposed on the emission layer EML. The first electron transport layer ETL1 can be directly disposed on the emission layer EML, but embodiments are not limited thereto. Although Figure 7 and Figure 8 are not shown, in an embodiment, a hole blocking layer HBL Figure 5 ) can be disposed between the first electron transport layer ETL1 and the emission layer EML.

[0281] The first electron transport layer ETL1 can be located adjacent to the emission layer EML, and the second electron transport layer ETL2 can be located adjacent to the second electrode EL2. The second electron transport layer ETL2 can be located closer to the second electrode EL2 than the first electron transport layer ETL1. The second electron transport layer ETL2 among the first electron transport layer ETL1 and the second electron transport layer ETL2, which is adjacent to the second electrode EL2, can have a first positive GSP. The second electron transport layer ETL2 can be an organic layer including a compound having the first positive GSP.

[0282] In the light emitting element ED shown in Figure 7 and Figure 8 , the first electron transport layer ETL1 can be located closer to the emission layer EML than the second electron transport layer ETL2, and can be spaced apart from the second electrode EL2. The first electron transport layer ETL1 can not have the first positive GSP. The first electron transport layer ETL1 can have a fifth positive GSP or a fifth negative GSP. The first electron transport layer ETL1 can be an organic layer including a compound having the fifth positive GSP or a compound having the fifth negative GSP. The fifth positive GSP can be different from the first positive GSP.

[0283] In an embodiment, the fifth positive GSP can have an absolute value equal to or smaller than about 10 mV / nm (|fifth positive GSP|≤10 mV / nm), and the fifth negative GSP can have an absolute value equal to or smaller than about 10 mV / nm (|fifth negative GSP|≤10 mV / nm). The fifth positive GSP and the fifth negative GSP suitable for the first electron transport layer ETL1 can each independently have an absolute value equal to or smaller than about 10 mV / nm, but embodiments are not limited thereto.

[0284] In an embodiment, the absolute value of the fifth positive GSP and the absolute value of the fifth negative GSP can each be not equal to or not greater than the absolute value of the first positive GSP (|fifth positive GSP or fifth negative GSP|<|first positive GSP|). Thus, when the first electron transport layer ETL1 has the fifth positive GSP or the fifth negative GSP, the fifth positive GSP and the fifth negative GSP of the first electron transport layer ETL1 can each have an absolute value smaller than the absolute value of the first positive GSP of the second electron transport layer ETL2. For example, when the first electron transport layer ETL1 has the fifth positive GSP, the fifth positive GSP of the first electron transport layer ETL1 can have a smaller absolute value than the first positive GSP of the second electron transport layer ETL2. Also, when the first electron transport layer ETL1 has the fifth negative GSP, the absolute value of the fifth negative GSP of the first electron transport layer ETL1 can be smaller than the absolute value of the first positive GSP of the second electron transport layer ETL2.

[0285] In an embodiment, when the electron transport layer ETL includes a plurality of electron transport layers, the electron transport layer ETL adjacent to the second electrode EL2 among the electron transport layers ETL can not have the first positive GSP. For example, in the light-emitting element ED shown in Figure 8 In the light-emitting element ED shown in Figure 8 In the light-emitting element ED shown in

[0286] Reference Figure 9The electron transport layer (ETL) can have a multilayer structure comprising three layers. The ETL may include a first electron transport layer ETL1, a second electron transport layer ETL2, and a third electron transport layer ETL3 disposed between the emitter layer EML and the second electrode EL2. The first electron transport layer ETL1, the second electron transport layer ETL2, and the third electron transport layer ETL3 can be sequentially disposed on the emitter layer EML. Therefore, the second electron transport layer ETL2 can be positioned closer to the second electrode EL2 than the first electron transport layer ETL1, and the third electron transport layer ETL3 can be positioned closer to the second electrode EL2 than the second electron transport layer ETL2. The first electron transport layer ETL1 is spaced further from the second electrode EL2 than the second electron transport layer ETL2 and the third electron transport layer ETL3, and can be adjacent to the emitter layer EML.

[0287] As described above, in an electron transport layer (ETL) with a multilayer structure, the ETL adjacent to the second electrode EL2 can have a first positive GSP. Figure 9 In the light-emitting element ED shown, at least one of the second electron transport layer ETL2 and the third electron transport layer ETL3 adjacent to the second electrode EL2 can independently have a first positive GSP. For example, among the first electron transport layer ETL1, the second electron transport layer ETL2, and the third electron transport layer ETL3, the second electron transport layer ETL2 can have a first positive GSP, and the first electron transport layer ETL1 and the third electron transport layer ETL3 can not have a first positive GSP. As another example, among the first electron transport layer ETL1, the second electron transport layer ETL2, and the third electron transport layer ETL3, the third electron transport layer ETL3 can have a first positive GSP, and the first electron transport layer ETL1 and the second electron transport layer ETL2 can not have a first positive GSP. The second electron transport layer ETL2 or the third electron transport layer ETL3 can be an organic layer including a compound having a first positive GSP.

[0288] exist Figure 9 In the light-emitting element (ED) shown, among the first electron transport layer ETL1, the second electron transport layer ETL2, and the third electron transport layer ETL3, the first electron transport layer ETL1 may be adjacent to the emitter layer EML and spaced apart from the second electrode EL2. The first electron transport layer ETL1 may not have a first positive GSP. In an embodiment, the first electron transport layer ETL1 may have a sixth positive GSP or a sixth negative GSP. In an embodiment, among the second electron transport layer ETL2 and the third electron transport layer ETL3, the layer without a first positive GSP may have a sixth positive GSP or a sixth negative GSP.

[0289] For example, the second electron transport layer ETL2 can have the first positive GSP. Accordingly, the first electron transport layer ETL1 and the third electron transport layer ETL3 can not have the first positive GSP. In an embodiment, the first electron transport layer ETL1 and the third electron transport layer ETL3 can each independently have a sixth positive GSP or a sixth negative GSP. The first electron transport layer ETL1 and the third electron transport layer ETL3 can each be an organic layer including a compound having the sixth positive GSP or a compound having the sixth negative GSP. The GSP of the first electron transport layer ETL1 and the GSP of the third electron transport layer ETL3 can be the same as or different from each other.

[0290] For example, the third electron transport layer ETL3 can have the first positive GSP, and the first electron transport layer ETL1 and the second electron transport layer ETL2 can each not have the first positive GSP. Accordingly, the first electron transport layer ETL1 and the second electron transport layer ETL2 can each independently have a sixth positive GSP or a sixth negative GSP. The first electron transport layer ETL1 and the second electron transport layer ETL2 can each be an organic layer including a compound having the sixth positive GSP or a compound having the sixth negative GSP. The GSP of the first electron transport layer ETL1 and the GSP of the second electron transport layer ETL2 can be the same as or different from each other.

[0291] In an embodiment, the absolute value of the sixth positive GSP can be equal to or less than about 10 mV / nm (|sixth positive GSP|≤10 mV / nm), and the absolute value of the sixth negative GSP can be equal to or less than about 10 mV / nm (|sixth negative GSP|≤10 mV / nm). The absolute value of the sixth positive GSP and the absolute value of the sixth negative GSP can each independently be equal to or less than about 10 mV / nm, but embodiments are not limited thereto.

[0292] In an embodiment, the absolute value of the sixth positive GSP can be not equal to or not greater than the absolute value of the first positive GSP (|sixth positive GSP|<|first positive GSP|), and the absolute value of the sixth negative GSP can be not equal to or not greater than the absolute value of the first positive GSP (|sixth negative GSP|<|first positive GSP|). Accordingly, the absolute value of the sixth positive GSP and the absolute value of the sixth negative GSP of the first electron transport layer ETL1 can each be less than the absolute value of the first positive GSP of the second electron transport layer ETL2 or the third electron transport layer ETL3. In an embodiment, the absolute value of the sixth positive GSP and the absolute value of the sixth negative GSP of the second electron transport layer ETL2 or the third electron transport layer ETL3 can each be less than the absolute value of the first positive GSP of the first electron transport layer ETL1.

[0293] For example, when the first electron transport layer ETL1 has a sixth positive GSP, the absolute value of the sixth positive GSP of the first electron transport layer ETL1 can be smaller than the absolute value of the first positive GSP of the second electron transport layer ETL2 or the third electron transport layer ETL3. For example, when the first electron transport layer ETL1 has a sixth negative GSP, the absolute value of the sixth negative GSP of the first electron transport layer ETL1 can be smaller than the absolute value of the first positive GSP of the second electron transport layer ETL2 or the third electron transport layer ETL3.

[0294] In an embodiment, when the second electron transport layer ETL2 has a sixth positive GSP and the third electron transport layer ETL3 has a first positive GSP, the absolute value of the sixth positive GSP of the second electron transport layer ETL2 can be smaller than the absolute value of the first positive GSP of the third electron transport layer ETL3. In an embodiment, when the second electron transport layer ETL2 has a sixth negative GSP and the third electron transport layer ETL3 has a first positive GSP, the absolute value of the sixth negative GSP of the second electron transport layer ETL2 can be smaller than the absolute value of the first positive GSP of the third electron transport layer ETL3. When the third electron transport layer ETL3 has a sixth positive GSP and the second electron transport layer ETL2 has a first positive GSP, the absolute value of the sixth positive GSP of the third electron transport layer ETL3 can be smaller than the absolute value of the first positive GSP of the second electron transport layer ETL2. When the third electron transport layer ETL3 has a sixth negative GSP and the second electron transport layer ETL2 has a first positive GSP, the absolute value of the sixth negative GSP of the third electron transport layer ETL3 can be smaller than the absolute value of the first positive GSP of the second electron transport layer ETL2.

[0295] In an embodiment, among the first electron transport layer ETL1, the second electron transport layer ETL2, and the third electron transport layer ETL3, at least one of the second electron transport layer ETL2 and the third electron transport layer ETL3 adjacent to the second electrode EL2 can not have a first positive GSP. For example, in the light-emitting element ED illustrated in FIG. 1A, the second electron transport layer ETL2 and / or the third electron transport layer ETL3 can not have a first positive GSP. Thus, as illustrated in FIG. 1A, the second electron transport layer ETL2 and / or the third electron transport layer ETL3 can have a second negative GSP. Figure 9 In the light-emitting element ED illustrated in FIG. 1A, the second electron transport layer ETL2 and / or the third electron transport layer ETL3 can not have a first positive GSP. Thus, as illustrated in FIG. 1A, the second electron transport layer ETL2 and / or the third electron transport layer ETL3 can have a second negative GSP. Figure 9

[0296] In the light-emitting element ED according to an embodiment, the electron transport region ETR can include a compound represented by Formula ET-2:

[0297] [Formula ET-2]

[0298]

[0299] ​In Formula ET-2, at least one of X1to X3may each be N, and the remaining groups of X1to X3may each independently be C(R a ). In Formula ET-2, R a may be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. In Formula ET-2, Ar1to Ar3may each independently be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.

[0300] In Formula ET-2, a to c can each independently be an integer of 0 to 10. In Formula ET-2, L1to L3may each independently be a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. When a to c are each 2 or greater, the multiple groups of each of L1to L3may each independently be a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms.

[0301] The electron transport region ETR can include an anthracene compound. However, embodiments are not limited thereto, and the electron transport region ETR can include, for example, tris(8-hydroxyquinoline)aluminum (Alq3), 1,3,5-tris[(3-pyridyl)-benzene-3-yl]benzene, 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzoimidazol-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-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD), bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum (BAlq), bis(10-hydroxybenzoquinoline)beryllium (Bebq2), 9,10-di(naphthalen-2-yl)anthracene (ADN), 1,3-bis[3,5-di(pyridin-3-yl)phenyl]benzene (BmPyPhB), or a mixture thereof.

[0302] In embodiments, the electron transport region ETR can include at least one of compounds ET1 to ET36:

[0303]

[0304]

[0305]

[0306]

[0307] In an embodiment, the electron transport region ETR can include a metal halide such as LiF, NaCl, CsF, RbCl, RbI, CuI, and KI; a lanthanide such as Yb; or a co-deposition material of a metal halide and a lanthanide. For example, the electron transport region ETR can include KI:Yb, RbI:Yb, LiF:Yb, or the like as a co-deposition material. The electron transport region ETR can include a metal oxide such as Li2O and BaO, or 8-(hydroxyquinoline)lithium (Liq), or the like, but embodiments are not limited thereto. In another embodiment, the electron transport region ETR can further include a mixture of an electron transport material and an insulating organic metal salt. The organic metal salt can be a material having an energy band gap equal to or greater than about 4 eV. For example, the organic metal salt can include a metal acetate, a metal benzoate, a metal acetylacetate, a metal acetylacetonate, or a metal stearate.

[0308] In addition to the above-described materials, the electron transport region ETR can further include at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), diphenyl(4-(triphenylsilyl)phenyl)phosphine oxide (TSPO1), and 4,7-diphenyl-1,10-phenanthroline (Bphen), but embodiments are not limited thereto.

[0309] The electron transport region ETR can include the above-described compounds of the electron transport region ETR in at least one of the electron injection layer EIL, the electron transport layer ETL, and the hole blocking layer HBL.

[0310] When the electron transport region ETR includes the electron transport layer ETL, the electron transport layer ETL can have a thickness in a range of about to about For example, the electron transport layer ETL can have a thickness in a range of about to about If the thickness of the electron transport layer ETL satisfies any of the above-described ranges, satisfactory electron transport characteristics can be obtained without a significant increase in driving voltage. When the electron transport region ETR includes the electron injection layer EIL, the electron injection layer EIL can have a thickness in a range of about to about For example, the electron injection layer EIL can have a thickness in a range of about to about If the thickness of the electron injection layer EIL satisfies any of the above-described ranges, satisfactory electron injection characteristics can be obtained without a significant increase in driving voltage.

[0311] The second electrode EL2 can be provided on the electron transport region ETR. The second electrode EL2 can be a common electrode. The second electrode EL2 can be a cathode or an anode, but embodiments are not limited thereto. For example, when the first electrode EL1 is an anode, the second electrode EL2 can be a cathode, and when the first electrode EL1 is a cathode, the second electrode EL2 can be an anode.

[0312] The second electrode EL2 can be a transmissive electrode, a semi-transmissive and semi-reflective electrode, or a reflective electrode. When the second electrode EL2 is a transmissive electrode, the second electrode EL2 can include a transparent metal oxide, for example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), or the like.

[0313] When the second electrode EL2 is a semi-transmissive and semi-reflective electrode or a reflective electrode, the second electrode EL2 can include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF, Mo, Ti, Yb, W, a compound thereof, or a mixture thereof (for example, AgMg, AgYb, or MgYb), or a material having a multi-layer structure such as LiF / Ca, LiF / Al. In an embodiment, the second electrode EL2 can have a multi-layer structure including a reflective film or a semi-transmissive and semi-reflective film formed of the above-described material and a transparent conductive film formed of ITO, IZO, ZnO, ITZO, or the like. For example, the second electrode EL2 can include the above-described metal material, a combination of at least two of the above-described metal materials, or an oxide of the above-described metal material, or the like.

[0314] Although not shown in the drawings, in an embodiment, the second electrode EL2 can be electrically connected to the auxiliary electrode. If the second electrode EL2 is electrically connected to the auxiliary electrode, the resistance of the second electrode EL2 can be reduced.

[0315] As shown in FIG. 1A, in an embodiment, the light emitting element ED can further include a capping layer CPL disposed on the second electrode EL2. The capping layer CPL can have a multi-layer structure or a single layer structure. Figure 10

[0316] In an embodiment, the capping layer CPL can include an organic layer or an inorganic layer. For example, when the capping layer CPL includes an inorganic material, the inorganic material can include an alkali metal compound (for example, LiF), an alkaline earth metal compound (for example, MgF2), SiON, SiN x , SiO y , or the like.

[0317] ​For example, when the capping layer CPL includes an organic material, the organic material can include α-NPD, NPB, TPD, m-MTDATA, Alq3, CuPc, N4,N4,N4',N4'-Tetrakis(3,5-dimethylphenyl)-4,4'-diaminostilbene (TPD15), 4,4',4"-Tris(9H-carbazol-9-yl)-triphenylamine (TCTA), or the like, or can include an epoxy-based resin, or an acrylate-based resin such as a methacrylate. However, embodiments are not limited thereto, and the capping layer CPL can include at least one of Compound P1 to Compound P5:

[0318]

[0319] The capping layer CPL can have a refractive index equal to or greater than about 1.6. For example, the capping layer CPL can have a refractive index equal to or greater than about 1.6 with respect to light in a wavelength range of about 550 nm to about 660 nm.

[0320] Figures 11A to 11E Each is a schematic cross-sectional view of a light-emitting element ED according to embodiments. Figures 11A to 11E Each shows a light-emitting element ED according to one of Figures 6 to 8 embodiments, and shows positive and negative charges induced on a surface of an emission layer EML, an electron-blocking layer EBL, a hole-transport layer HTL, and / or an electron-transport layer ETL to show GSP characteristics provided from each layer.

[0321] In the light-emitting element ED shown in Figures 11A to 11E , the electron-blocking layer EBL included in the hole-transport region HTR can have a surface potential in which positive charges PC are induced in a direction toward the first electrode EL1 and negative charges NC are induced in a direction toward the second electrode EL2. The electron-blocking layer EBL can have a first negative GSP as described above. In the light-emitting element ED shown in Figures 11A to 11E , the emission layer EML can have a surface potential in which negative charges NC are induced in a direction toward the first electrode EL1 and positive charges PC are induced in a direction toward the second electrode EL2. The emission layer EML can have a fourth positive GSP as described above.

[0322] In the light-emitting element ED shown in Figure 11AIn the light-emitting element ED illustrated in FIG. 1, the hole-transport layer HTL can have a single-layer structure, and the electron-transport layer ETL can have a multi-layer structure. For example, the hole-transport layer HTL can include a first hole-transport layer HTL1 and a second hole-transport layer HTL2. Among the first hole-transport layer HTL1 and the second hole-transport layer HTL2, the second hole-transport layer HTL2 adjacent to the emission layer EML can have a surface potential in which a positive charge PC is induced in a direction toward the first electrode EL1 and a negative charge NC is induced in a direction toward the second electrode EL2. The second hole-transport layer HTL2 can have a second negative GSP as described above. The electron-transport layer ETL having a single-layer structure can have a fifth positive GSP or a fifth negative GSP, but embodiments are not limited thereto.

[0323] In Figure 11B In the light-emitting element ED illustrated in FIG. 1, the hole-transport layer HTL can have a single-layer structure, and the electron-transport layer ETL can have a multi-layer structure. For example, the hole-transport layer HTL can include a first hole-transport layer HTL1 and a second hole-transport layer HTL2. Among the first hole-transport layer HTL1 and the second hole-transport layer HTL2, the second hole-transport layer HTL2 adjacent to the emission layer EML can have a surface potential in which a positive charge PC is induced in a direction toward the first electrode EL1 and a negative charge NC is induced in a direction toward the second electrode EL2. The second hole-transport layer HTL2 can have a second negative GSP as described above. The electron-transport layer ETL having a single-layer structure can have a fifth positive GSP or a fifth negative GSP, but embodiments are not limited thereto.

[0324] In Figures 11C to 11E In the light-emitting element ED illustrated in FIG. 1, the hole-transport layer HTL can have a single-layer structure, and the electron-transport layer ETL can have a multi-layer structure. For example, the hole-transport layer HTL can include a first hole-transport layer HTL1 and a second hole-transport layer HTL2. Among the first hole-transport layer HTL1 and the second hole-transport layer HTL2, the second hole-transport layer HTL2 adjacent to the emission layer EML can have a surface potential in which a positive charge PC is induced in a direction toward the first electrode EL1 and a negative charge NC is induced in a direction toward the second electrode EL2. The second hole-transport layer HTL2 can have a second negative GSP as described above. The electron-transport layer ETL having a single-layer structure can have a fifth positive GSP or a fifth negative GSP, but embodiments are not limited thereto.

[0325] Reference Figure 11CAmong the first hole transport layer HTL1 and the second hole transport layer HTL2, the second hole transport layer HTL2 adjacent to the emission layer EML can have a surface potential in which a positive charge PC is induced in a direction toward the first electrode EL1 and a negative charge NC is induced in a direction toward the second electrode EL2. Among the first electron transport layer ETL1 and the second electron transport layer ETL2, the second electron transport layer ETL2 adjacent to the second electrode EL2 can have a surface potential in which a negative charge NC is induced in a direction toward the first electrode EL1 and a positive charge PC is induced in a direction toward the second electrode EL2. For example, the second hole transport layer HTL2 can have a second negative GSP, the first hole transport layer HTL1 can have a second positive GSP or a third negative GSP, and the first electron transport layer ETL1 and the second electron transport layer ETL2 can each independently have a fifth positive GSP or a fifth negative GSP.

[0326] Reference Figure 11D Among the first hole transport layer HTL1 and the second hole transport layer HTL2, the second hole transport layer HTL2 adjacent to the emission layer EML can have a surface potential in which a positive charge PC is induced in a direction toward the first electrode EL1 and a negative charge NC is induced in a direction toward the second electrode EL2. For example, the second hole transport layer HTL2 can have a second negative GSP, the first hole transport layer HTL1 can have a second positive GSP or a third negative GSP, and the first electron transport layer ETL1 and the second electron transport layer ETL2 can each independently have a fifth positive GSP or a fifth negative GSP.

[0327] Reference Figure 11E Among the first electron transport layer ETL1 and the second electron transport layer ETL2, the second electron transport layer ETL2 adjacent to the second electrode EL2 can have a surface potential in which a negative charge NC is induced in a direction toward the first electrode EL1 and a positive charge PC is induced in a direction toward the second electrode EL2. For example, the second electron transport layer ETL2 can have a first positive GSP, the first hole transport layer HTL1 and the second hole transport layer HTL2 can each independently have a second positive GSP or a third negative GSP, and the first electron transport layer ETL1 can have a fifth positive GSP or a fifth negative GSP.

[0328] Figures 12 to 15 Each is a schematic cross-sectional view of a display device DD-a, DD-TD, DD-b, and DD-c according to embodiments. Hereinafter, in the description of the display devices DD-a, DD-TD, DD-b, and DD-c according to embodiments as shown in FIGS. 1A to 1C, features already described above with respect to the display devices DD-a, DD-TD, DD-b, and DD-c according to embodiments as shown in FIGS. 1A to 1C will not be described again, and different features will be described. Figures 12 to 15 Figures 1 to 11E ​​

[0329] Referring to Figure 12 , the display device DD-a according to embodiments can include a display panel DP including a display device layer DP-ED, a light control layer CCL disposed on the display panel DP, and a color filter layer CFL. In Figure 12 embodiments shown in FIG. 1A, the display panel DP can include a base layer BS, a circuit layer DP-CL provided on the base layer BS, and a display device layer DP-ED, and the display device layer DP-ED can include a light emitting element ED.

[0330] The light emitting element ED can include a first electrode EL1, a hole transport region HTR disposed on the first electrode EL1, an emission layer EML disposed on the hole transport region HTR, an electron transport region ETR disposed on the emission layer EML, and a second electrode EL2 disposed on the electron transport region ETR. In embodiments, Figure 12 the structure of the light emitting element ED shown in FIG. 1A can be the same as the structure of the light emitting element ED according to one of the embodiments as described above. Figures 3 to 10

[0331] The emission layer EML of the light emitting element ED included in the display device DD-a according to embodiments can include at least one hole transport layer HTL and / or at least one electron transport layer ETL as described above.

[0332] Referring to Figure 12 , the emission layer EML can be disposed in the opening OH defined in the pixel definition film PDL. For example, the emission layer EML separated by the pixel definition film PDL and provided to each of the light emitting regions PXA-R, PXA-G, and PXA-B can emit light in the same wavelength range. In the display device DD-a, the emission layer EML can emit blue light. Although not shown in the drawings, in embodiments, the emission layer EML can be provided as a common layer for all the light emitting regions PXA-R, PXA-G, and PXA-B.

[0333] The light control layer CCL can be disposed on the display panel DP. The light control layer CCL can include a light converter. The light converter can be a quantum dot or a phosphor, etc. The light converter can convert the wavelength of the provided light and emit the resulting light. For example, the light control layer CCL can be a layer including a quantum dot or a layer including a phosphor.

[0334] The light control layer CCL can include light control portions CCP1, CCP2, and CCP3. The light control portions CCP1, CCP2, and CCP3 can be spaced apart from each other.

[0335] Referring to Figure 12 ​The separation pattern BMP can be disposed between the light control portions CCP1, CCP2, and CCP3 spaced apart from each other, but embodiments are not limited thereto. In Figure 12 The separation pattern BMP can be disposed between the light control portions CCP1, CCP2, and CCP3 spaced apart from each other, but embodiments are not limited thereto. In

[0336] The light control layer CCL can include a first light control portion CCP1 including first quantum dots QD1 that convert first color light provided from the light emitting element ED into second color light, a second light control portion CCP2 including second quantum dots QD2 that convert the first color light into third color light, and a third light control portion CCP3 that transmits the first color light. In embodiments, the first light control portion CCP1 can provide red light as the second color light, and the second light control portion CCP2 can provide green light as the third color light. The third light control portion CCP3 can provide blue light by transmitting blue light as the first color light provided from the light emitting element ED. For example, the first quantum dots QD1 can be red quantum dots, and the second quantum dots QD2 can be green quantum dots. The quantum dots QD1 and QD2 can each be quantum dots as described above.

[0337] The light control layer CCL can further include scatterers SP. The first light control portion CCP1 can include the first quantum dots QD1 and the scatterers SP, the second light control portion CCP2 can include the second quantum dots QD2 and the scatterers SP, and the third light control portion CCP3 can not include any quantum dots but can include the scatterers SP.

[0338] The scatterers SP can be inorganic particles. For example, the scatterers SP can include at least one of TiO2, ZnO, Al2O3, and SiO2 (e.g., hollow silica). The scatterers SP can include one of TiO2, ZnO, Al2O3, and SiO2 (e.g., hollow silica), or can be a mixture of at least two materials selected from TiO2, ZnO, Al2O3, and SiO2 (e.g., hollow silica).

[0339] The first, second, and third light control portions CCP1, CCP2, and CCP3 can each include a base resin BR1, BR2, and BR3 in which quantum dots QD1 and QD2 and scatterers SP are dispersed. In an embodiment, the first light control portion CCP1 can include first quantum dots QD1 and scatterers SP dispersed in a first base resin BR1, the second light control portion CCP2 can include second quantum dots QD2 and scatterers SP dispersed in a second base resin BR2, and the third light control portion CCP3 can include scatterers SP dispersed in a third base resin BR3.

[0340] The base resins BR1, BR2, and BR3 are media in which the quantum dots QD1 and QD2 and the scatterers SP are dispersed, and can include various resin compositions that can be referred to as binders. For example, the base resins BR1, BR2, and BR3 can be acrylic resins, urethane resins, silicone resins, epoxy resins, or the like. The base resins BR1, BR2, and BR3 can each be a transparent resin. In an embodiment, the first, second, and third base resins BR1, BR2, and BR3 can be the same as or different from each other.

[0341] The light control layer CCL can include a barrier layer BFL1. The barrier layer BFL1 can prevent the permeation of moisture and / or oxygen (hereinafter, referred to as "moisture / oxygen"). The barrier layer BFL1 can block the light control portions CCP1, CCP2, and CCP3 from being exposed to moisture / oxygen. The barrier layer BFL1 can cover the light control portions CCP1, CCP2, and CCP3. In an embodiment, a barrier layer BFL2 can be disposed between the light control portions CCP1, CCP2, and CCP3 and the color filter layer CFL.

[0342] The barrier layers BFL1 and BFL2 can each independently include at least one inorganic layer. For example, the barrier layers BFL1 and BFL2 can each independently include an inorganic material. For example, the barrier layers BFL1 and BFL2 can each independently 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, a metal that ensures light transmission, or the like. The barrier layers BFL1 and BFL2 can each independently further include an organic film. The barrier layers BFL1 and BFL2 can be formed of a single layer or a plurality of layers.

[0343] In the display device DD-a, the color filter layer CFL can be disposed on the light control layer CCL. In an embodiment, the color filter layer CFL can be directly disposed on the light control layer CCL. For example, the barrier layer BFL2 can be omitted.

[0344] The color filter layer CFL can include color filters CF1, CF2, and CF3. The color filter layer CFL can include a first color filter CF1 that transmits second color light, a second color filter CF2 that transmits third color light, and a third color filter CF3 that transmits first color light. For example, the first color filter CF1 can be a red color filter, the second color filter CF2 can be a green color filter, and the third color filter CF3 can be a blue color filter. The color filters CF1, CF2, and CF3 can each include a polymeric photosensitive resin and a pigment or a dye. The first color filter CF1 can include a red pigment or a dye, the second color filter CF2 can include a green pigment or a dye, and the third color filter CF3 can include a blue pigment or a dye.

[0345] However, embodiments are not limited thereto, and the third color filter CF3 can not include a pigment or a dye. The third color filter CF3 can include a polymeric photosensitive resin, and can not include a pigment or a dye. The third color filter CF3 can be transparent. The third color filter CF3 can be formed of a transparent photosensitive resin.

[0346] In embodiments, the first color filter CF1 and the second color filter CF2 can each be a yellow color filter. The first color filter CF1 and the second color filter CF2 can not be provided as separate color filters, and can be provided as an integrated color filter.

[0347] Although not shown in the drawings, in embodiments, the color filter layer CFL can further include a light shielding portion (not shown). The light shielding portion (not shown) can be a black matrix. The light shielding portion (not shown) can include an organic light shielding material or an inorganic light shielding material, each of which includes a black pigment or a black dye. The light shielding portion (not shown) can prevent light leakage, and can separate boundaries between adjacent color filters CF1, CF2, and CF3.

[0348] The first color filter CF1, the second color filter CF2, and the third color filter CF3 can be disposed such that they correspond to a red light emitting area PXA-R, a green light emitting area PXA-G, and a blue light emitting area PXA-B, respectively. A base substrate BL can be disposed on the color filter layer CFL. The base substrate BL can provide a base surface on which the color filter layer CFL and the light control layer CCL, etc., are disposed. The base substrate BL can be a glass substrate, a metal substrate, a plastic substrate, etc. However, embodiments are not limited thereto, and the base substrate BL can include an inorganic layer, an organic layer, or a composite material layer. Although not shown in the drawings, in embodiments, the base substrate BL can be omitted.

[0349] Figure 13is a schematic cross-sectional view of a portion of a display device DD-TD according to an embodiment. In the display device DD-TD according to an embodiment, the light emitting element ED-BT can include light emitting structures OL-B1, OL-B2, and OL-B3. The light emitting element ED-BT can include first and second electrodes EL1 and EL2 facing each other and the light emitting structures OL-B1, OL-B2, and OL-B3 stacked in a thickness direction between the first and second electrodes EL1 and EL2. The light emitting structures OL-B1, OL-B2, and OL-B3 can each include a hole transport region HTR, an emission layer EML( Figure 12 ), and an electron transport region ETR, which can be disposed between the first and second electrodes EL1 and EL2 in the following order.

[0350] For example, the light emitting element ED-BT included in the display device DD-TD can be a light emitting element having a series structure including a plurality of emission layers.

[0351] In the embodiment shown in Figure 13 , the light emitted from the light emitting structures OL-B1, OL-B2, and OL-B3 can each be blue light. However, embodiments are not limited thereto, and the light emitted from the light emitting structures OL-B1, OL-B2, and OL-B3 can have wavelength ranges different from each other. For example, the light emitting element ED-BT including the light emitting structures OL-B1, OL-B2, and OL-B3 emitting light in different wavelength ranges can emit white light.

[0352] The charge generation layers CGL1 and CGL2 can each be disposed between two adjacent light emitting structures among the light emitting structures OL-B1, OL-B2, and OL-B3. The charge generation layers CGL1 and CGL2 can each independently include a p-type charge generation layer and / or an n-type charge generation layer.

[0353] Figure 14 is a schematic cross-sectional view of a display device DD-b according to an embodiment. Figure 15 is a schematic cross-sectional view of a display device DD-c according to an embodiment.

[0354] Referring to Figure 14 , the display device DD-b according to an embodiment can include light emitting elements ED-1, ED-2, and ED-3 in which two emission layers are stacked. Compared to the display device DD shown in Figure 2 , the display device DD-b can include a light emitting element ED-1, ED-2, and ED-3 in which two emission layers are stacked. Figure 14The embodiment illustrated in FIG. 1 is different from the embodiment illustrated in FIG. 2 in that the first light emitting element ED-1, the second light emitting element ED-2, and the third light emitting element ED-3 each include two emission layers stacked in a thickness direction. In the first light emitting element ED-1, the second light emitting element ED-2, and the third light emitting element ED-3, the two emission layers can emit light in the same wavelength region.

[0355] The first light emitting element ED-1 can include a first red emission layer EML-R1 and a second red emission layer EML-R2. The second light emitting element ED-2 can include a first green emission layer EML-G1 and a second green emission layer EML-G2. The third light emitting element ED-3 can include a first blue emission layer EML-B1 and a second blue emission layer EML-B2. An emission assistance part OG can be disposed between the first red emission layer EML-R1 and the second red emission layer EML-R2, between the first green emission layer EML-G1 and the second green emission layer EML-G2, and between the first blue emission layer EML-B1 and the second blue emission layer EML-B2.

[0356] The emission assistance part OG can have a single-layer structure or a multi-layer structure. The emission assistance part OG can include charge generation layers CGL1, CGL2, and CGL3 (see FIG. 3). For example, the emission assistance part OG can include an electron transport region, a charge generation layer, and a hole transport region, which can be stacked in the following order. The emission assistance part OG can be provided as a common layer for the first light emitting element ED-1, the second light emitting element ED-2, and the third light emitting element ED-3. However, embodiments are not limited thereto, and the emission assistance part OG can be provided by being patterned within the opening OH defined in the pixel definition film PDL. Figure 15 )>. For example, the emission assistance part OG can include an electron transport region, a charge generation layer, and a hole transport region, which can be stacked in the following order. The emission assistance part OG can be provided as a common layer for the first light emitting element ED-1, the second light emitting element ED-2, and the third light emitting element ED-3. However, embodiments are not limited thereto, and the emission assistance part OG can be provided by being patterned within the opening OH defined in the pixel definition film PDL.

[0357] The first red emission layer EML-R1, the first green emission layer EML-G1, and the first blue emission layer EML-B1 can be disposed between the emission assistance part OG and the electron transport region ETR. The second red emission layer EML-R2, the second green emission layer EML-G2, and the second blue emission layer EML-B2 can be disposed between the hole transport region HTR and the emission assistance part OG.

[0358] The first light emitting element ED-1 can include a first electrode EL1, a hole transport region HTR, a second red emission layer EML-R2, an emission auxiliary part OG, a first red emission layer EML-R1, an electron transport region ETR, and a second electrode EL2 stacked in this order. The second light emitting element ED-2 can include a first electrode EL1, a hole transport region HTR, a second green emission layer EML-G2, an emission auxiliary part OG, a first green emission layer EML-G1, an electron transport region ETR, and a second electrode EL2 stacked in this order. The third light emitting element ED-3 can include a first electrode EL1, a hole transport region HTR, a second blue emission layer EML-B2, an emission auxiliary part OG, a first blue emission layer EML-B1, an electron transport region ETR, and a second electrode EL2 stacked in this order.

[0359] An optical auxiliary layer PL can be disposed on the display device layer DP-ED. The optical auxiliary layer PL can include a polarizing layer. The optical auxiliary layer PL can be disposed on the display panel DP and can control light reflected at the display panel DP from external light. Although not shown in the drawings, in an embodiment, the optical auxiliary layer PL can be omitted from the display device DD-b.

[0360] With Figure 13 and Figure 14 comparison, Figure 15 A display device DD-c is shown, which differs at least in that it includes four light emitting structures OL-B1, OL-B2, OL-B3, and OL-C1. The light emitting element ED-CT can include a first electrode EL1 and a second electrode EL2 facing each other and a first light emitting structure OL-B1, a second light emitting structure OL-B2, a third light emitting structure OL-B3, and a fourth light emitting structure OL-C1 stacked in a thickness direction between the first electrode EL1 and the second electrode EL2. The charge generation layers CGL1, CGL2, and CGL3 can each be disposed between two adjacent light emitting structures among the first light emitting structure OL-B1, the second light emitting structure OL-B2, the third light emitting structure OL-B3, and the fourth light emitting structure OL-C1. Among the four light emitting structures OL-B1, OL-B2, OL-B3, and OL-C1, the first light emitting structure OL-B1, the second light emitting structure OL-B2, and the third light emitting structure OL-B3 can each emit blue light, and the fourth light emitting structure OL-C1 can emit green light. However, embodiments are not limited thereto, and the first light emitting structure OL-B1, the second light emitting structure OL-B2, the third light emitting structure OL-B3, and the fourth light emitting structure OL-C1 can emit light in wavelength regions different from each other.

[0361] The charge generation layers CGL1, CGL2, and CGL3 can each independently include a p-type charge generation layer and / or an n-type charge generation layer.

[0362] The light emitting element according to the embodiment includes an electron blocking layer having a first negative GSP, and a layer adjacent to the emission layer among the plurality of hole transport layers has a negative GSP, and / or a layer adjacent to the second electrode among the plurality of electron transport layers has a positive GSP, and thus, the capacitance can be reduced, the resistance can be reduced, and the displacement of the standard chromaticity can be lowered. Accordingly, the light emitting element can exhibit a low driving voltage. When the light emitting element according to the embodiment is included in a display device, the capacitance of a specific pixel can be increased, thereby preventing a problem of "first frame response" related to color deviation caused when a screen is scrolled in the display device. Accordingly, the light emitting element when included in a display device can prevent a display quality problem caused by a delay in the turn-on time of the light emitting element due to RC (resistance-capacitance) delay when a display device having a high refresh rate is implemented.

[0363] In one or more embodiments, an electronic device can include a display device including a plurality of light emitting elements and a control part that controls the display device. The electronic device of one or more embodiments can be a device that is activated according to an electric signal. The electronic device can include a display device of one or more suitable embodiments. For example, the electronic device can include not only a large electronic device such as a television, a monitor, or an outdoor billboard, but also a medium or small electronic device such as a personal computer, a laptop computer, a personal digital terminal, a display device for a vehicle, a game machine, a portable electronic device, or a camera.

[0364] The display device, electronic device, means of manufacturing the display device, or any other related device or component described herein according to embodiments of this disclosure can be implemented using any suitable hardware, firmware (e.g., application-specific integrated circuit), software, or a combination of software, firmware, and hardware. For example, one or more suitable components of the display device and / or electronic device can be formed in an integrated circuit (IC) chip or in a separate IC chip. Furthermore, one or more suitable components of the display device and / or electronic device can be implemented on a flexible printed circuit film, a tape-on-a-chip (TCP), a printed circuit board (PCB), or formed on a substrate. Additionally, one or more suitable components of the display device and / or electronic device can be a process or thread that runs in one or more processors in one or more computing devices, executes computer program instructions, and interacts with other system components for performing one or more suitable functions described herein. The computer program instructions are stored in a memory that can be implemented in a computing device using a standard storage device, such as random access memory (RAM). The computer program instructions can also be stored in other non-transitory computer-readable media, such as read-only optical disc storage (CD-ROM) or flash memory drives. Furthermore, those skilled in the art will recognize that, without departing from the scope of the embodiments of this disclosure, the functionality of one or more suitable computing devices may be combined or integrated into a single computing device, or the functionality of a particular computing device may be distributed across one or more other computing devices.

[0365] In the following description, a light-emitting element according to an embodiment will be described with reference to examples and comparative examples. The examples shown below are provided only to facilitate understanding of this disclosure, and the scope of this disclosure is not limited thereto.

[0366] [Example]

[0367] 1. Fabrication of light-emitting elements

[0368] To fabricate the light-emitting element according to the example and comparative example, a glass substrate (Corning, 15Ω / cm) on which an ITO electrode is formed is used as the anode. 2 , Cut into pieces approximately 50mm × 50mm × 0.7mm in size, ultrasonically cleaned with isopropanol and pure water for 5 minutes each, irradiated with ultraviolet light for 30 minutes, and then cleaned by exposure to ozone before installation on a vacuum deposition equipment.

[0369] In the upper part of the anode, a p-doped agent is deposited to form a structure with... A hole injection layer of a certain thickness, and on the upper part of the hole injection layer, a layer with... a hole-transporting layer having a thickness of 100 nm, and on the upper part of the hole-transporting layer, a cathode having a thickness of 200 nm was formed by depositing AgMg (10%). an electron-transporting layer having a thickness of 100 nm.

[0370] a hole-transporting layer having a thickness of 100 nm, and on the upper part of the hole-transporting layer, a cathode having a thickness of 200 nm was formed by depositing AgMg (10%). an electron-transporting layer having a thickness of 100 nm. an electron-transporting layer having a thickness of 100 nm. an electron-transporting layer having a thickness of 100 nm. to prepare a light-emitting element.

[0371] Each layer was formed by vacuum deposition. As for the hole-transporting layer and the electron-transporting layer, the materials listed in Table 1 below were used. Each element was prepared to have a pixel size of 2 mm x 2 mm.

[0372] The compounds used for the preparation of the light-emitting elements in the examples and comparative examples were purified by sublimation and commercially available products used for the preparation of elements.

[0373] In Table 1, "-" indicates that the corresponding layer was not formed, In-GSP indicates that the compound EBL1 has a huge surface potential equal to or smaller than approximately -10 mV / nm, and 2p-GSP indicates that the compound 2,4,6-tris(diphenyl-3-yl)-l,3,5-triazine has a huge surface potential equal to or larger than approximately 10 mV / nm. 1ab-GSP has a small absolute value of GSP than In-GSP. 4p-GSP is an emission layer having a huge surface potential equal to or larger than approximately 10 mV / nm, and includes SiCzCz as a hole-transporting host, SiTrzCz2 as an electron-transporting host, and the compound M-b-12 as a phosphorescent dopant (deposition ratio of hole-transporting host: electron-transporting host: phosphorescent dopant = 5.5:3.5: 1). The compound 1ab-GSP is a material having an absolute value of GSP equal to or smaller than approximately 10 mV / nm, and its structure is shown below, and SiCzCz is a material having a negative GSP and having an absolute value of GSP equal to or smaller than approximately 10 mV / nm. The compound 2ab-GSP is mSiTrZ which has substantially no GSP or has a low GSP, and an absolute value of GSP is equal to or smaller than approximately 10 mV / nm.

[0374] (Compounds used in the preparation of light-emitting elements)

[0375]

[0376] [Table 1]

[0377] HTL1 HTL2 EBL EML ETL1 ETL2 Example 1 1ab-GSP 1n-GSP 1n-GSP 4p-GSP 2ab-GSP - Example 2 1ab-GSP - 1n-GSP 4p-GSP 2ab-GSP 1p-GSP Example 3 1ab-GSP 1n-GSP 1n-GSP 4p-GSP 2ab-GSP 1p-GSP Comparative Example 1 1ab-GSP - SiCzCz 4p-GSP 2ab-GSP - Comparative Example 2 1ab-GSP - 1n-GSP 4p-GSP 2ab-GSP - Comparative Example 3 1n-GSP - 1n-GSP 4p-GSP 2ab-GSP - Comparative Example 4 1n-GSP 1ab-GSP 1n-GSP 4p-GSP 2ab-GSP - Comparative Example 5 1ab-GSP 1ab-GSP 1n-GSP 4p-GSP 1p-GSP - Comparative Example 6 1ab-GSP - 1n-GSP 4p-GSP 1p-GSP 2ab-GSP Comparative Example 7 1p-GSP - 1n-GSP 4p-GSP 2ab-GSP - Comparative Example 8 1ab-GSP 1p-GSP 1n-GSP 4p-GSP 2ab-GSP - Comparative Example 9 1p-GSP 1ab-GSP 1n-GSP 4p-GSP 2ab-GSP - Comparative Example 10 1ab-GSP 1ab-GSP 1n-GSP 4p-GSP 1n-GSP - Comparative Example 11 1ab-GSP 1ab-GSP 1n-GSP 4p-GSP 2ab-GSP 1n-GSP Comparative Example 12 1ab-GSP 1ab-GSP 1n-GSP 4p-GSP 1n-GSP 2ab-GSP Comparative Example 13 1ab-GSP 1n-GSP SiCzCz 4p-GSP 2ab-GSP - Comparative Example 14 1ab-GSP 1n-GSP 1p-GSP 4p-GSP 2ab-GSP -

[0378] 2. Property evaluation of light-emitting element

[0379] Table 2 shows evaluation results of the light-emitting elements for Example 1 to Example 3 and Comparative Example 1 to Comparative Example 14. To evaluate the light-emitting element characteristics of Example 1 to Example 3 and Comparative Example 1 to Comparative Example 14, the maximum capacitance (C max ) was measured from about -2 V to about 5 V in a capacitance-voltage mode with the frequency of an impedance analyzer set to about 1000 Hz and VAC (voltage alternating current) set to about 100 mV, and the value having the maximum capacitance was calculated. The resistance at 4 V (R = V / I at 4 V) was calculated by measuring the resistance of the light-emitting elements of Example 1 to Example 3 and Comparative Example 1 to Comparative Example 14 at 4 V.

[0380] The standard chromaticity shift (Δu'v') was measured after a panel composed of red, green, and blue pixels was produced using the light-emitting elements of Example 1 to Example 3 and Comparative Example 1 to Comparative Example 14. The luminance ratio of each RGB (red, green, and blue) pixel was 0.24, 0.68, and 0.08, and for each example and comparative example, the color coordinates of the 1st frame and the 10th frame were calculated after the start of panel operation. The maximum efficiency of white was 400 nits, but when the color coordinates of the 1st frame and the 10th frame were compared, the luminance was measured in the low gray scale range under conditions corresponding to 11 grays based on the blue 10th frame. Using the x, y color coordinates obtained from the measurement, u'v' was converted by the formulas u' = 4x / (-2x + 12y + 3) and v' = 9y / (-2x + 12y + 3), and Δu'v' was calculated by the formula Δu'v' = sqrt(u'^2 + v'^2).

[0381] The measurement results of the maximum capacitance (C max ), the resistance, and the standard chromaticity shift (Δu'v') are shown in Table 2. The standard chromaticity shift can be expressed as a shift in standard chromaticity or a shift value in standard chromaticity, or the like.

[0382] [Table 2]

[0383]

[0384]

[0385] Referring to the results in Table 2, it was found that the light-emitting element of the example had a low maximum capacitance (C max ), a resistance, and / or a shift in standard chromaticity (Δu'v') compared to the light-emitting elements of the comparative examples.

[0386] In Example 1, the electron-blocking layer was found to have a negative GSP, and the second hole-transport layer among the plurality of hole-transport layers adjacent to the emission layer was found to have a negative GSP, resulting in a maximum capacitance (C max ) indicating a low capacitance. Example 1 was found to have a low resistance value compared to Comparative Examples, and to have a small shift in standard chromaticity value of less than 0.01, resulting in excellent color characteristics.

[0387] In Example 2, the electron-blocking layer was found to have a negative GSP, and the second electron-transport layer among the plurality of electron-transport layers adjacent to the second electrode (cathode) was found to have a positive GSP, resulting in a low capacitance and a small shift in standard chromaticity. Example 2 was found to have a low resistance compared to some of the Comparative Examples.

[0388] In Example 3, the electron-blocking layer was found to have a negative GSP, and both the hole-transport layer and the electron-transport layer were found to have GSP characteristics according to the embodiments, resulting in a low capacitance and a small shift in standard chromaticity. Example 3 was found to have a low resistance compared to some of the Comparative Examples.

[0389] In contrast, in Comparative Example 1, none of the electron-blocking layer, the hole-transport layer, and the electron-transport layer were found to have GSP characteristics according to the embodiments, and Comparative Example 1 exhibited a high capacitance, and a shift in standard chromaticity value of greater than 0.01, which is greater than the shift in standard chromaticity value of the light-emitting elements of the Examples.

[0390] In Comparative Example 2, although the electron-blocking layer included a material having a negative GSP characteristic, the holes were over-blocked, resulting in a relatively high resistance of the light-emitting element. In Comparative Example 2, the hole-transport layer and the electron-transport layer each had a single layer structure and did not have GSP characteristics according to the embodiments, resulting in Comparative Example 2 exhibiting a high resistance value compared to the light-emitting elements according to the Examples, and also exhibiting a large shift in standard chromaticity.

[0391] It was seen that Comparative Example 3 included an electron-blocking layer and a hole-transport layer each having a negative GSP, but the single hole-transport layer had a negative GSP, and Comparative Example 3 exhibited a relatively high capacitance compared to the Examples, and also exhibited a large shift in standard chromaticity value of greater than 0.01.

[0392] It was seen that Comparative Example 4 included an electron-blocking layer and a hole-transport layer each having a negative GSP, but the hole-transport layer among the two hole-transport layers adjacent to the first electrode had a negative GSP, and Comparative Example 4 exhibited a relatively high capacitance compared to the Examples, and also exhibited a large shift in standard chromaticity value of greater than 0.01.

[0393] Comparative Example 5 includes an electron blocking layer having a negative GSP and an electron transport layer having a positive GSP, but the hole transport layer adjacent to the emission layer among the plurality of hole transport layers does not have a negative GSP. Comparative Example 5 shows a high capacitance and a large resistance value than the example, and shows a large shift in standard chromaticity.

[0394] Comparative Example 6 has a structure in which, among two electron transport layers, the electron transport layer having a positive GSP is adjacent to the emission layer and is spaced apart from the second electrode. Comparative Example 6 shows a higher capacitance than the example, and shows a large resistance and a large shift in standard chromaticity.

[0395] Comparative Examples 7 to 9 each have a structure in which the hole transport layer having a single layer structure has a positive GSP, or one of the two hole transport layers has a positive GSP. Comparative Examples 7 to 9 show a significantly high resistance and a high shift in standard chromaticity than the example.

[0396] Comparative Examples 10 to 12 each have a structure in which the electron transport layer having a single layer structure has a negative GSP, or one of the two electron transport layers has a negative GSP. It is found that Comparative Examples 10 to 12 have a resistance at a similar level to the example, but Comparative Examples 10 to 12 also have a higher capacitance than the example, and also have a large shift in standard chromaticity value greater than 0.01. As shown by Comparative Examples 10 to 12, having a negative GSP does not make it better in preventing electron leakage.

[0397] Comparative Example 13 includes a structure in which the second hole transport layer among the plurality of hole transport layers adjacent to the emission layer has a negative GSP. In Comparative Example 13, the electron blocking layer does not include a material having a negative GSP, and thus has a poor effect in suppressing hole injection or preventing electron leakage. Accordingly, it is found that Comparative Example 13 has a higher capacitance than the example, and also has a large shift in standard chromaticity greater than 0.01.

[0398] Comparative Example 14 includes a structure in which the electron blocking layer has a positive GSP and the second hole transport layer among the plurality of hole transport layers adjacent to the emission layer has a negative GSP. Accordingly, it is found that Comparative Example 14 has a higher capacitance than the example, and also has a large shift in standard chromaticity value greater than 0.01.

[0399] The light emitting element according to the embodiment can exhibit a low capacitance, and also show a low resistance and a low shift in standard chromaticity. Accordingly, the light emitting element can exhibit a low driving voltage property.

[0400] The display device according to the embodiment includes the above-described light emitting element, and thus can provide enhanced display quality.

[0401] Embodiments have been disclosed herein and, although the terms are employed in the description, they are used and interpreted only in a generic and descriptive sense and not for purposes of limitation. In some instances, features, characteristics and / or elements described in connection with an embodiment can be used independently of each other or in combination with other features, characteristics and / or elements described in connection with another embodiment, as would be apparent to one of ordinary skill in the art. Thus, one of ordinary skill in the art would understand that the various changes in form and details can be made without departing from the spirit and scope of the disclosure as set forth in the following claims.

Claims

1. A light emitting element, wherein, The light-emitting element includes: a first electrode; a hole-transport region provided over the first electrode; an emission layer provided over the hole-transport region; an electron-transport region provided over the emission layer; and a second electrode provided over the electron-transport region, wherein the hole-transport region includes: a hole-injection layer provided over the first electrode; at least one hole-transport layer provided over the hole-injection layer; and an electron-blocking layer provided over the hole-transport layer and having a first negative huge surface potential, the electron-transport region includes: at least one electron-transport layer provided over the emission layer; and an electron-injection layer provided over the electron-transport layer, the at least one hole-transport layer includes a plurality of hole-transport layers, and / or the at least one electron-transport layer includes a plurality of electron-transport layers, when the light-emitting element includes the plurality of hole-transport layers, a hole-transport layer adjacent to the emission layer among the plurality of hole-transport layers has a second negative huge surface potential, and when the light-emitting element includes the plurality of electron-transport layers, an electron-transport layer adjacent to the second electrode among the plurality of electron-transport layers has a first positive huge surface potential.

2. The light-emitting element according to claim 1, wherein The second negative huge surface potential has an absolute value smaller than that of the first negative huge surface potential.

3. The light-emitting element according to claim 1, wherein The first negative huge surface potential is equal to or smaller than -10 mV / nm.

4. The light-emitting element according to claim 1, wherein the at least one hole-transport layer includes: a first hole-transport layer provided over the hole-injection layer; and a second hole-transport layer provided over the first hole-transport layer and having the second negative huge surface potential, and the second negative huge surface potential is equal to or smaller than -10 mV / nm.

5. The light-emitting element according to claim 4, wherein the first hole-transport layer has a second positive huge surface potential or a third negative huge surface potential, and an absolute value of the second positive huge surface potential and an absolute value of the third negative huge surface potential are each independently equal to or smaller than 10 mV / nm.

6. The light-emitting element according to claim 5, wherein The second positive huge surface potential and the third negative huge surface potential each have a smaller absolute value than the second negative huge surface potential.

7. The light-emitting element according to claim 1, wherein the at least one hole-transport layer includes: a first hole-transport layer provided over the hole-injection layer; a second hole-transport layer provided over the first hole-transport layer; and a third hole-transport layer provided over the second hole-transport layer, at least one of the second hole-transport layer and the third hole-transport layer has the second negative huge surface potential, and the second negative huge surface potential is equal to or smaller than -10 mV / nm.

8. The light-emitting element according to claim 7, wherein the second hole-transport layer has the second negative huge surface potential, the first hole-transport layer and the third hole-transport layer each independently have a third positive huge surface potential or a fourth negative huge surface potential, and the third positive huge surface potential and the fourth negative huge surface potential each have a smaller absolute value than the second negative huge surface potential. An absolute value of the third positive giant surface potential and an absolute value of the fourth negative giant surface potential are each independently equal to or less than 10 mV / nm.

9. The light-emitting element according to claim 7, wherein the third hole-transport layer has the second negative giant surface potential, the first hole-transport layer and the second hole-transport layer each independently have a third positive giant surface potential or a fourth negative giant surface potential, and an absolute value of the third positive giant surface potential and an absolute value of the fourth negative giant surface potential are each independently equal to or less than 10 mV / nm.

10. The light-emitting element according to claim 1, wherein the emission layer has a fourth positive giant surface potential.

11. The light-emitting element according to claim 1, wherein the at least one electron-transport layer includes: a first electron-transport layer provided over the emission layer; and a second electron-transport layer provided over the first electron-transport layer and having the first positive giant surface potential, and the first positive giant surface potential is equal to or greater than 10 mV / nm.

12. The light-emitting element according to claim 11, wherein the first electron-transport layer has a fifth positive giant surface potential or a fifth negative giant surface potential, and an absolute value of the fifth positive giant surface potential and an absolute value of the fifth negative giant surface potential are each independently equal to or less than 10 mV / nm.

13. The light-emitting element according to claim 1, wherein the at least one electron-transport layer includes: a first electron-transport layer provided over the emission layer; a second electron-transport layer provided over the first electron-transport layer; and a third electron-transport layer provided over the second electron-transport layer, the second electron-transport layer or the third electron-transport layer has the first positive giant surface potential, and the first positive giant surface potential is equal to or greater than 10 mV / nm.

14. The light-emitting element according to claim 13, wherein the second electron-transport layer has the first positive giant surface potential, the first electron-transport layer and the third electron-transport layer each independently have a sixth positive giant surface potential or a sixth negative giant surface potential, and an absolute value of the sixth positive giant surface potential and an absolute value of the sixth negative giant surface potential are each independently equal to or less than 10 mV / nm.

15. The light-emitting element according to claim 13, wherein the third electron-transport layer has the first positive giant surface potential, the first electron-transport layer and the second electron-transport layer each independently have a sixth positive giant surface potential or a sixth negative giant surface potential, and an absolute value of the sixth positive giant surface potential and an absolute value of the sixth negative giant surface potential are each independently equal to or less than 10 mV / nm.

16. The light-emitting element according to claim 1, wherein the at least one hole-transport layer includes: a first hole-transport layer provided over the hole-injection layer; and a second hole-transport layer provided over the first hole-transport layer and having the second negative giant surface potential, the at least one electron-transport layer includes a first electron-transport layer provided over the emission layer, the second negative macroscopic surface potential is equal to or smaller than -10 mV / nm, and the absolute value of the macroscopic surface potential of the first hole transport layer and the absolute value of the macroscopic surface potential of the first electron transport layer are each independently equal to or smaller than 10 mV / nm.

17. The light-emitting element according to claim 1, wherein the at least one hole transport layer includes a first hole transport layer provided over the hole injection layer, the at least one electron transport layer includes: a first electron transport layer provided over the emission layer; and a second electron transport layer provided over the first electron transport layer and having the first positive macroscopic surface potential, the first positive macroscopic surface potential is equal to or larger than 10 mV / nm, and the absolute value of the macroscopic surface potential of the first hole transport layer and the absolute value of the macroscopic surface potential of the first electron transport layer are each independently equal to or smaller than 10 mV / nm.

18. The light-emitting element according to claim 1, wherein the at least one hole transport layer includes: a first hole transport layer provided over the hole injection layer; and a second hole transport layer provided over the first hole transport layer and having the second negative macroscopic surface potential, the at least one electron transport layer includes: a first electron transport layer provided over the emission layer; and a second electron transport layer provided over the first electron transport layer and having the first positive macroscopic surface potential, the second negative macroscopic surface potential is equal to or smaller than -10 mV / nm, the first positive macroscopic surface potential is equal to or larger than 10 mV / nm, and the absolute value of the macroscopic surface potential of the first hole transport layer and the absolute value of the macroscopic surface potential of the first electron transport layer are each independently equal to or smaller than 10 mV / nm.

19. An electronic device, wherein, the electronic device includes: a display device including: a circuit layer provided over a base layer; a pixel definition film provided over the circuit layer and having a plurality of pixel openings defined in the pixel definition film; and a plurality of light-emitting elements provided over the circuit layer, wherein each of the plurality of light-emitting elements includes a first electrode, a hole transport region, an emission layer, an electron transport region, and a second electrode which are sequentially stacked, the hole transport region includes: a hole injection layer provided over the first electrode; at least one hole transport layer provided over the hole injection layer; and an electron blocking layer provided over the hole transport layer and having a first negative macroscopic surface potential, the electron transport region includes: at least one electron transport layer provided over the emission layer; and an electron injection layer provided over the electron transport layer, the at least one hole transport layer includes a plurality of hole transport layers, and / or the at least one electron transport layer includes a plurality of electron transport layers, when the at least one hole transport layer includes the plurality of hole transport layers, a hole transport layer adjacent to the emission layer among the plurality of hole transport layers has a second negative macroscopic surface potential, and the second negative macroscopic surface potential is equal to or smaller than -10 mV / nm, and the absolute value of the macroscopic surface potential of the first hole transport layer and the absolute value of the macroscopic surface potential of the first electron transport layer are each independently equal to or smaller than 10 mV / nm. When the at least one electron transport layer includes the plurality of electron transport layers, an electron transport layer adjacent to the second electrode among the plurality of electron transport layers has a first positive giant surface potential. 20.The electronic device of claim 19, wherein, The display device further includes: a light control layer including quantum dots; and a color filter layer disposed on the light control layer, wherein the color filter layer includes: a first color filter that transmits red light; a second color filter that transmits green light; and a third color filter that transmits blue light.

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