ORGANIC LIGHT-EMITTING DEVICE

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from the benefit of Korean Patent Application No. 10-2019-0022576, filed on Feb. 26, 2019, which is hereby by reference for all purposes as if fully set forth herein.

BACKGROUND
Field

Exemplary embodiments of the invention relate generally to an organic light-emitting device.

Discussion of the Background

Organic light-emitting devices are self-emission devices that produce full-color images, and also have wide viewing angles, high contrast ratios, short response times, and excellent characteristics in terms of brightness, driving voltage, and response speed, compared to devices in the art.

The organic light-emitting device may include a first electrode disposed on a substrate, and a hole transport region, an emission layer, an electron transport region, and a second electrode, which are sequentially disposed on the first electrode. Holes provided from the first electrode may move toward the emission layer through the hole transport region, and electrons provided from the second electrode may move toward the emission layer through the electron transport region. Carriers, such as holes and electrons, recombine in the emission layer to produce excitons. These excitons transit from an excited state to a ground state, thereby generating light.

The above information disclosed in this Background section is only for understanding of the background of the inventive concepts, and, therefore, it may contain information that does not constitute prior art.

SUMMARY

Devices constructed according to exemplary embodiments of the invention may provide an organic light-emitting device including an auxiliary layer that is disposed between an emission layer and a hole blocking layer and which includes a material having a lowest excitation triplet energy level in a predetermined range.

Additional features of the inventive concepts will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the inventive concepts.

According to one or more exemplary embodiments of the invention, an organic light-emitting device includes: a first electrode; a second electrode facing the first electrode; an organic layer including an emission layer between the first electrode and the second electrode and an electron transport region between the second electrode and the emission layer; and a first auxiliary layer between the emission layer and the electron transport region. The electron transport region includes a hole blocking layer between the second electrode and the first auxiliary layer, the emission layer includes a host, and the first auxiliary layer may include a first compound, and the organic light-emitting device satisfies Equation 1, wherein when the host and the first compound are identical to each other, the first auxiliary layer consists of the first compound only:

T
₁(C1)≤T₁(H). <Equation 1>

In Equation 1, T₁(C1) is a lowest excitation triplet energy level of the first compound, and T₁(H) is a lowest excitation triplet energy level of the host.

The emission layer may be in direct contact with the first auxiliary layer.

The first auxiliary layer may exist at an interface between the emission layer and the hole blocking layer.

A thickness of the first auxiliary layer may be in a range of about 5 Å to about 100 Å.

In one embodiment, T₁(H) may be 3.0 eV or less.

The emission layer may emit green fluorescence or delayed fluorescence having a maximum emission wavelength in a range of about 490 nm to about 590 nm.

The emission layer may further include a dopant.

The dopant may emit fluorescence or delayed fluorescence.

The electron transport region may further include an electron transport layer between the second electrode and the hole blocking layer, and the electron transport layer may include an electron transport material.

The organic light-emitting device may further include a hole transport region between the first electrode and the emission layer, and the hole transport region may include a hole transport material.

The hole transport region may include an electron blocking layer.

The organic light-emitting device may further include a second auxiliary layer between the electron blocking layer and the emission layer, and the second auxiliary layer may include a second compound and satisfy Equation 2, wherein when the host included in the emission layer and the second compound are identical to each other, the second auxiliary layer may consist of the second compound only:

T
₁(C2)≤T₁(H). <Equation 2>

In Equation 2, T₁(C2) is a lowest excitation triplet energy level of the second compound, and T₁(H) is a lowest excitation triplet energy level of the host.

The emission layer may be in direct contact with the second auxiliary layer.

The second auxiliary layer may exist at an interface between the emission layer and the electron blocking layer.

The hole transport region may further include a hole transport layer between the first electrode and the hole blocking layer, and the hole transport layer may include a hole transport material.

The host may be a single host.

The host may be a mixed host including a hole transport host and an electron transport host.

The organic light-emitting device may further include a hole transport region between the first electrode and the emission layer, the hole transport region may include an electron blocking layer, the host may be a mixed host including a hole transport host and an electron transport host, the hole transport host may exist at a side closer to the electron blocking layer in the emission layer, and the electron transport host may exist at a side closer to the hole blocking layer in the emission layer.

In one embodiment, the first compound may be represented by one selected from Formulae 1 to 3:

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In Formulae 1 to 3, Ar₁may be a substituted or unsubstituted C₅-C₆₀carbocyclic group or a substituted or unsubstituted C₁-C₆₀heterocyclic group,

a1 may be 1, 2, or 3,

L₁and L₁₁to L₁₄may each independently be selected from a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

L₁₅may be selected from *—O—*′, *—S—*′, *—N(Q₁₁)-*′, a substituted or unsubstituted C₁-C₂₀alkylene group, a substituted or unsubstituted C₂-C₂₀alkenylene group, a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

a11 may be an integer from 0 to 5,

b11 to b14 may each independently be an integer from 0 to 3,

b15 may be an integer from 1 to 10,

R₁may be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a substituted or unsubstituted C₁-C₆₀alkyl group, a substituted or unsubstituted C₂-C₆₀alkenyl group, a substituted or unsubstituted C₂-C₆₀alkynyl group, a substituted or unsubstituted C₁-C₆₀alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀arylthio group, a substituted or unsubstituted C₁-C₆₀heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂), —B(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)₂(Q₁), and —P(═O)(Q₁)(Q₂),

R₁₁to R₁₄and Q₁₁may each independently be selected from a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀arylthio group, a substituted or unsubstituted C₁-C₆₀heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group,

a21 may be an integer from 1 to 5, and

Q₁to Q₃may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

In an embodiment, Ar₁may be selected from:

a carbazole group, a benzocarbazole group, a dibenzocarbazole group, an indole group, a benzoindole group, a dibenzoindole group, a triazine group, a furan group, an acridine group, a phenoxazine group, and a phenothiazine group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and

Q₃₁to Q₃₃may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

According to another exemplary embodiment of the invention, a display apparatus may include: a thin-film transistor including a source electrode, a drain electrode, and an activation layer; and the organic light-emitting device, wherein the first electrode of the organic light-emitting device may be electrically connected to one of the source electrode and the drain electrode.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention, and together with the description serve to explain the inventive concepts.

These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic view of an organic light-emitting device according to an embodiment;

FIG. 2 is a schematic view of an organic light-emitting device according to an embodiment; and

FIG. 3 is a graph showing the lifespan of the organic light-emitting devices of Examples 1 and 2 and Comparative Examples 1 and 2.

DETAILED DESCRIPTION

In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of various exemplary embodiments or implementations of the invention. As used herein “embodiments” and “implementations” are interchangeable words that are non-limiting examples of devices or methods employing one or more of the inventive concepts disclosed herein. It is apparent, however, that various exemplary embodiments may be practiced without these specific details or with one or more equivalent arrangements. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring various exemplary embodiments. Further, various exemplary embodiments may be different, but do not have to be exclusive. For example, specific shapes, configurations, and characteristics of an exemplary embodiment may be used or implemented in another exemplary embodiment without departing from the inventive concepts.

Unless otherwise specified, the illustrated exemplary embodiments are to be understood as providing exemplary features of varying detail of some ways in which the inventive concepts may be implemented in practice. Therefore, unless otherwise specified, the features, components, modules, layers, films, panels, regions, and/or aspects, etc. (hereinafter individually or collectively referred to as “elements”), of the various embodiments may be otherwise combined, separated, interchanged, and/or rearranged without departing from the inventive concepts.

The use of cross-hatching and/or shading in the accompanying drawings is generally provided to clarify boundaries between adjacent elements. As such, neither the presence nor the absence of cross-hatching or shading conveys or indicates any preference or requirement for particular materials, material properties, dimensions, proportions, commonalities between illustrated elements, and/or any other characteristic, attribute, property, etc., of the elements, unless specified. Further, in the accompanying drawings, the size and relative sizes of elements may be exaggerated for clarity and/or descriptive purposes. When an exemplary embodiment may be implemented differently, a specific process order may be performed differently from the described order. For example, two consecutively described processes may be performed substantially at the same time or performed in an order opposite to the described order. Also, like reference numerals denote like elements.

When an element, such as a layer, is referred to as being “on,” “connected to,” or “coupled to” another element or layer, it may be directly on, connected to, or coupled to the other element or layer or intervening elements or layers may be present. When, however, an element or layer is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element or layer, there are no intervening elements or layers present. To this end, the term “connected” may refer to physical, electrical, and/or fluid connection, with or without intervening elements. Further, the D1-axis, the D2-axis, and the D3-axis are not limited to three axes of a rectangular coordinate system, such as the x, y, and z-axes, and may be interpreted in a broader sense. For example, the D1-axis, the D2-axis, and the D3-axis may be perpendicular to one another, or may represent different directions that are not perpendicular to one another. For the purposes of this disclosure, “at least one of X, Y, and Z” and “at least one selected from the group consisting of X, Y, and Z” may be construed as X only, Y only, Z only, or any combination of two or more of X, Y, and Z, such as, for instance, XYZ, XYY, YZ, and ZZ. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

Although the terms “first,” “second,” etc. may be used herein to describe various types of elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another element. Thus, a first element discussed below could be termed a second element without departing from the teachings of the disclosure.

Spatially relative terms, such as “beneath,” “below,” “under,” “lower,” “above,” “upper,” “over,” “higher,” “side” (e.g., as in “sidewall”), and the like, may be used herein for descriptive purposes, and, thereby, to describe one elements relationship to another element(s) as illustrated in the drawings. Spatially relative terms are intended to encompass different orientations of an apparatus in use, operation, and/or manufacture in addition to the orientation depicted in the drawings. For example, if the apparatus in the drawings is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. Furthermore, the apparatus may be otherwise oriented (e.g., rotated 90 degrees or at other orientations), and, as such, the spatially relative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting. As used herein, the singular forms, “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Moreover, the terms “comprises,” “comprising,” “includes,” and/or “including,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, and/or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It is also noted that, as used herein, the terms “substantially,” “about,” and other similar terms, are used as terms of approximation and not as terms of degree, and, as such, are utilized to account for inherent deviations in measured, calculated, and/or provided values that would be recognized by one of ordinary skill in the art.

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

Hereinafter, exemplary embodiments are described in detail by referring to the attached drawings, and in the drawings, like reference numerals denote like elements, and a redundant explanation thereof will not be provided herein.

A sample in which a compound is deposited on a quartz substrate to a thickness of 1,000 Å is prepared, a photoluminescence spectrum of the sample is obtained at a temperature of 4 K, the first peak (peak having the shortest wavelength) of the photoluminescence spectrum is analyzed to calculate a lowest excitation triplet energy level (T₁energy level).

The term “organic layer” as used herein refers to a single layer and/or a plurality of layers disposed between an anode and a cathode of an organic light-emitting device. A material included in the “organic layer” is not limited to an organic material.

The expression “(an organic layer) includes at least one compound” as used herein may include as a case in which “(an organic layer) includes identical compounds represented by Formula 1” or a case in which “(an organic layer) includes two or more different compounds represented by Formula 1”.

Hereinafter, exemplary embodiments of the inventive concepts will be described in detail with reference to the attached drawings.

FIGS. 1 and 2 are schematic views of organic light-emitting devices 10 and 20 according to an exemplary embodiment. The organic light-emitting devices 10 and 20 may each include a first electrode 110, an emission layer 150, and a second electrode 190.

Referring to FIGS. 1 and 2, the organic light-emitting device 10 and 20 may each include: a first electrode 110; a second electrode 190 facing the first electrode 110; an organic layer including an emission layer 150 between the first electrode 110 and the second electrode 190 and an electron transport region 170 between the second electrode 190 and the emission layer 150; and a first auxiliary layer 160 between the emission layer 150 and the electron transport region 170, wherein the electron transport region 170 may include a hole blocking layer 171 between the second electrode 190 and the first auxiliary layer 160, the emission layer 150 may include a host, and the first auxiliary layer 160 may include a first compound, and the organic light-emitting device may satisfy Equation 1, wherein, when the host and the first compound are identical to each other, the first auxiliary layer 160 may consist of the first compound only:

T
₁(C1)≤T₁(H). <Equation 1>

In Equation 1,

T₁(C1) is a lowest excitation triplet energy level of the first compound, and

T₁(H) is a lowest excitation triplet energy level of the host.

As described above, when the first auxiliary layer 160 is disposed between the emission layer 150 and the hole blocking layer 171 and a lowest excitation triplet energy level (T₁(C1)) of the first compound included in the first auxiliary layer 160 is less than or equal to a lowest excitation triplet energy level (T₁(H)) of the host included in the emission layer 150, the lifespan of the organic light-emitting device may be improved by adjusting triplet excitons in a light emission zone formed at an interface between the emission layer 150 and the hole blocking layer 171, and the concentration of triplet excitons by triplet quenching may be reduced.

The first compound included in the first auxiliary layer 160 is not particularly limited as long as the first compound is within a range satisfying Equation 1. As described above, when the first compound is identical to the host included in the emission layer 150, the first auxiliary layer 160 may consist of the first compound only. Since the first auxiliary layer 160 consists of the first compound only, the lifespan of the organic light-emitting device may be improved by the principle of efficiently causing reduction of triplet excitons to the same compound, without reducing device efficiency and increasing driving voltage.

The hole blocking layer 171 differs from an electron transport layer 172 to be described below, and includes a hole blocking material. The hole blocking layer 171 may be understood by referring to the description provided below.

Since the organic light-emitting devices 10 and 20 each include the separate first auxiliary layer 160 that is different from the electron transport layer 172 and disposed between the hole blocking layer 171 and the emission layer 150, triplet excitons concentrated in the light emission zone (recombination zone) by the first auxiliary layer may be dispersed, and excitons discharged to the electron transport layer by the hole blocking layer may be blocked, thereby increasing the efficiency and lifespan of the organic light-emitting device.

The emission layer 150 may be in direct contact with the first auxiliary layer 160. For example, the first auxiliary layer 160 may exist at an interface between the emission layer 150 and the hole blocking layer 171.

In this manner, the organic light-emitting devices 10 and 20 may substantially block excitons generated in the emission layer 150 from moving to the electron transport region 170 without participating in light emission, thereby increasing the triplet concentration in the emission layer 150. Therefore, the efficiency of the organic light-emitting device may be improved.

In order to obtain the above-described effect, the emission layer 150 and the first auxiliary layer 160 essentially directly contact each other, and no other layers should not be disposed between the emission layer 150 and the first auxiliary layer 160.

In one exemplary embodiment, a thickness of the first auxiliary layer 160 may be in a range of about 5 Å to about 100 Å. When the thickness of the first auxiliary layer 160 is within this range, the desired efficiency improvement effect may be obtained without increasing the driving voltage of the organic light-emitting device.

In one exemplary embodiment, the emission layer 150 may emit green fluorescence or delayed fluorescence having a maximum emission wavelength in a range of about 490 nm to about 590 nm.

In one exemplary embodiment, the emission layer 150 may further include a dopant.

In one exemplary embodiment, T₁(H) may be about 3.0 eV or less. For example, T₁(H) may be about 2.7 V or less. Furthermore, the singlet energy and the triplet energy of the dopant may satisfy the following equation.

ΔEst=S1−T1<0.3 eV (ΔEst is a difference between the singlet energy and the triplet energy).

In this manner, the organic light-emitting device may emit thermally activated delayed fluorescence (TADF).

For example, the dopant may emit fluorescence or delayed fluorescence. For example, the dopant may emit delayed fluorescence.

The dopant that emits the delayed fluorescence may be disposed at an interface between the emission layer 150 and the first auxiliary layer 160 or the second auxiliary layer 140. Therefore, a light-emitting position may exist at the interface between the emission layer 150 and the first auxiliary layer 160 or the second auxiliary layer 140.

In one exemplary embodiment, the electron transport region 170 may further include an electron transport layer 172 between the second electrode 190 and the hole blocking layer 171, and the electron transport layer 172 may include an electron transport material. The electron transport layer 172 may be understood by referring to the description provided below.

Referring to FIG. 2, the organic light-emitting device 20 may further include a hole transport region 130 between the first electrode 110 and the emission layer 150, and the hole transport region 130 may include a hole transport material. The hole transport region 130 may be understood by referring to the description provided below.

The hole transport region 130 may include an electron blocking layer 131. The electron blocking layer 131 differs from a hole transport layer 132 to be described below, and includes an electron blocking material. The electron blocking layer 131 may be understood by referring to the description provided below.

The organic light-emitting device 20 may further include a second auxiliary layer 140 between the electron blocking layer 131 and the emission layer 150, and the second auxiliary layer 140 may include a second compound. The organic light-emitting device 20 may satisfy Equation 2, wherein, when the host included in the emission layer 150 and the second compound are identical to each other, the second auxiliary layer may consist of the second compound only:

T
₁(C2)≤T₁(H). <Equation 2>

In Equation 2,

T₁(C2) is a lowest excitation triplet energy level of the second compound, and

T₁(H) is a lowest excitation triplet energy level of the host.

In one exemplary embodiment, the emission layer 150 may be in direct contact with the second auxiliary layer 140. For example, the second auxiliary layer 140 may exist at an interface between the emission layer 150 and the electron blocking layer 131.

Other contents of the second auxiliary layer 140 may be understood by referring to the description of the first auxiliary layer 160.

In one exemplary embodiment, the hole transport region 130 may further include a hole transport layer 132 between the first electrode 110 and the electron blocking layer 131, and the hole transport layer 132 may include a hole transport material.

In one exemplary embodiment, the host included in the emission layer 150 may be a single host.

In one or more exemplary embodiments, the host included in the emission layer 150 may be a mixed host including a hole transport host and an electron transport host.

In one exemplary embodiment, the organic light-emitting device 20 may further include a hole transport region 130 between the first electrode 110 and the emission layer 150, and the hole transport region 130 may include an electron blocking layer 131. The host may be a mixed host including a hole transport host and an electron transport host. The hole transport host may exist on a side close to the electron blocking layer 131 in the emission layer 150, and the electron transport host may exist on a side close to the hole blocking layer 161 in the emission layer 150.

Hereinafter, the components of the organic light-emitting device according to one or more exemplary embodiments will be described with reference to FIGS. 1 and 2.

Referring to FIGS. 1 and 2, a substrate may be additionally disposed under the first electrode 110 or above the second electrode 190. The substrate may be a glass substrate or a plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and water resistance.

The first electrode 110 may be formed by depositing or sputtering a material for forming the first electrode 110 on the substrate. When the first electrode 110 is an anode, the material for forming the first electrode 110 may be selected from materials with a high work function to facilitate hole injection.

The first electrode 110 may be a reflective electrode, a semi-reflective electrode, or a transmissive electrode. When the first electrode 110 is a transmissive electrode, a material for forming a first electrode may be selected from indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO₂), zinc oxide (ZnO), and any combinations thereof, but exemplary embodiments of the inventive concepts are not limited thereto. In one or more exemplary embodiments, when the first electrode 110 is a semi-transmissive electrode or a reflectable electrode, a material for forming a first electrode may be selected from magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), and any combinations thereof, but exemplary embodiments of the inventive concepts are not limited thereto.

The first electrode 110 may have a single-layered structure, or a multi-layered structure including two or more layers. For example, the first electrode 110 may have a three-layered structure of ITO/Ag/ITO, but the structure of the first electrode 110 is not limited thereto.

The organic emission layer 150 may be disposed on the first electrode 110. The organic layer may include an electron transport region 170 between the emission layer 150 and the second electrode 190.

The organic layer may further include a hole transport region 130 between the first electrode 110 and the emission layer 150.

The hole transport region 130 may have i) a single-layered structure including a single layer including a single material, ii) a single-layered structure including a single layer including a plurality of different materials, or iii) a multi-layered structure having a plurality of layers including a plurality of different materials.

The hole transport region 130 may include at least one layer selected from an electron blocking layer, a hole transport layer 132, and an emission auxiliary layer.

For example, the hole transport region 130 may have a single-layered structure including a single layer including a plurality of different materials, or a multi-layered structure having a hole injection layer/hole transport layer structure, a hole injection layer/hole transport layer/emission auxiliary layer structure, a hole injection layer/emission auxiliary layer structure, a hole injection layer/hole transport layer/electron blocking layer structure, a hole injection layer/hole transport layer/emission auxiliary layer/electron blocking layer structure, a hole injection layer/emission auxiliary layer/electron blocking layer structure or a hole transport layer (132)/emission auxiliary layer/electron blocking layer structure, wherein for each structure, constituting layers are sequentially stacked from the first electrode 110 in this stated order, but exemplary embodiments of the inventive concepts are not limited thereto.

The hole transport region 130 may include at least one selected from m-MTDATA, TDATA, 2-TNATA, NPB (NPD), β—NPB, TPD, spiro-TPD, spiro-NPB, methylated-NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS), polyaniline/camphor sulfonic acid (PANI/CSA), polyaniline/poly(4-styrenesulfonate) (PANI/PSS), a compound represented by Formula 201, and a compound represented by Formula 202:

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In Formulae 201 and 202,

L₂₀₁to L₂₀₄may each independently be selected from a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

L₂₀₅may be selected from *—O—*′, *—S—*′, *—N(Q₂₀₁)-*′, a substituted or unsubstituted C₁-C₂₀alkylene group, a substituted or unsubstituted C₂-C₂₀alkenylene group, a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

xa1 to xa4 may each independently be an integer from 0 to 3,

xa5 may be an integer from 1 to 10, and

R₂₀₁to R₂₀₄and Q₂₀₁may each independently be selected from a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀arylthio group, a substituted or unsubstituted C₁-C₆₀heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group.

For example, R₂₀₁and R₂₀₂in Formula 202 may optionally be linked via a single bond, a dimethyl-methylene group, or a diphenyl-methylene group, and R₂₀₃and R₂₀₄in Formula 202 may optionally be linked via a single bond, a dimethyl-methylene group, or a diphenyl-methylene group.

In one exemplary embodiment, in Formulae 201 and 202,

L₂₀₁to L₂₀₅may each independently be selected from:

a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an indacenylene group, an acenaphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a rubicenylene group, a coronenylene group, an ovalenylene group, a thiophenylene group, a furanylene group, a carbazolylene group, an indolylene group, an isoindolylene group, a benzofuranylene group, a benzothiophenylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, a dibenzosilolylene group, and a pyridinylene group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a phenyl group substituted with a C₁-C₁₀alkyl group, a phenyl group substituted with —F, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), and —N(Q₃₁)(Q₃₂), and

Q₃₁to Q₃₃may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

In one or more exemplary embodiments, xa1 to xa4 may each independently be 0, 1, or 2.

In one or more exemplary embodiments, xa5 may be 1, 2, 3, or 4.

In one or more exemplary embodiments, R₂₀₁to R₂₀₄and Q₂₀₁may each independently be selected from:

a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a phenyl group substituted with a C₁-C₁₀alkyl group, a phenyl group substituted with —F, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), and —N(Q₃₁)(Q₃₂), and

Q₃₁to Q₃₃are the same as described above.

In one or more exemplary embodiments, at least one selected from R₂₀₁to R₂₀₃in Formula 201 may each independently be selected from:

a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group; and

a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a phenyl group substituted with a C₁-C₁₀alkyl group, a phenyl group substituted with —F, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group,

but exemplary embodiments of the inventive concepts are not limited thereto.

In one or more exemplary embodiments, in Formula 202, i) R₂₀₁and R₂₀₂may be linked via a single bond, and/or ii) R₂₀₃and R₂₀₄may be linked via a single bond.

In one or more exemplary embodiments, at least one selected from R₂₀₁to R₂₀₄in

Formula 202 may each independently be selected from:

a carbazolyl group; and

a carbazolyl group substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a phenyl group substituted with a C₁-C₁₀alkyl group, a phenyl group substituted with —F, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group,

but exemplary embodiments of the inventive concepts are not limited thereto.

The compound represented by Formula 201 may be represented by Formula 201A:

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In one exemplary embodiment, the compound represented by Formula 201 may be represented by Formula 201A(1) below, but exemplary embodiments of the inventive concepts are not limited thereto:

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In one exemplary embodiment, the compound represented by Formula 201 may be represented by Formula 201A-1 below, but exemplary embodiments of the inventive concepts are not limited thereto:

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In one exemplary embodiment, the compound represented by Formula 202 may be represented by Formula 202A:

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In one exemplary embodiment, the compound represented by Formula 202 may be represented by Formula 202A-1:

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L₂₀₁to L₂₀₃, xa1 to xa3, xa5, and R₂₀₂to R₂₀₄are the same as described above,

R₂₁₁and R₂₁₂may each independently be the same as defined in connection with R₂₀₃, and

R₂₁₃to R₂₁₇may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a phenyl group substituted with a C₁-C₁₀alkyl group, a phenyl group substituted with —F, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl group.

The hole transport region may include at least one compound selected from Compounds HT1 to HT39, but exemplary embodiments of the inventive concepts are not limited thereto:

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A thickness of the hole transport region 130 may be in a range of about 100 Å to about 10,000 Å, for example, about 100 Å to about 1,000 Å. When the hole transport region 130 includes at least one selected from a hole injection layer and a hole transport layer 132, the thickness of the hole injection layer may be in a range of about 100 Å to about 9,000 Å, and for example, about 100 Å to about 1,000 Å, and the thickness of the hole transport layer 132 may be in a range of about 50 Å to about 2,000 Å, and for example, about 100 Å to about 1,500 Å. When the thicknesses of the hole transport region 130, the hole injection layer, and the hole transport layer 132 are within these ranges, satisfactory hole transporting characteristics may be obtained without a substantial increase in driving voltage.

The emission auxiliary layer may increase light-emission efficiency by compensating for an optical resonance distance according to the wavelength of light emitted by an emission layer, and the electron blocking layer 131 may block the flow of electrons from the electron transport region 170. The emission auxiliary layer and the electron blocking layer 131 may include the materials as described above.

The hole transport region 130 may further include, in addition to these materials, a charge-generation material for the improvement of conductive properties. The charge-generation material may be homogeneously or non-homogeneously dispersed in the hole transport region 130.

The charge-generation material may be, for example, a p-dopant.

In one exemplary embodiment, the p-dopant may have a lowest unoccupied molecular orbital (LUMO) level of −3.5 eV or less.

The p-dopant may include at least one selected from a quinone derivative, a metal oxide, and a cyano group-containing compound, but exemplary embodiments of the inventive concepts are not limited thereto.

In one exemplary embodiment, the p-dopant may include at least one selected from:

a quinone derivative, such as tetracyanoquinodimethane (TCNQ) or 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ);

a metal oxide, such as tungsten oxide or molybdenum oxide;

1,4,5,8,9,12-hexaazatriphenylene-hexacarbonitrile (HAT-CN); and

a compound represented by Formula 221,

but exemplary embodiments of the inventive concepts are not limited thereto:

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In Formula 221,

R₂₂₁to R₂₂₃may each independently be selected from a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀aryl group, a substituted or unsubstituted C₁-C₆₀heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, wherein at least one selected from R₂₂₁to R₂₂₃may each independently have at least one substituent selected from a cyano group, —F, —Cl, —Br, —I, a C₁-C₂₀alkyl group substituted with —F, a C₁-C₂₀alkyl group substituted with —Cl, a C₁-C₂₀alkyl group substituted with —Br, and a C₁-C₂₀alkyl group substituted with —I.

The electron blocking material included in the electron blocking layer 131 may satisfy 2.5 eV≤T₁(BL)≤3.5 eV, but exemplary embodiments of the inventive concepts are not limited thereto. When the electron blocking material is within this range, excitons may be substantially trapped in the emission layer, and excitons may sufficiently participate in light emission.

The electron blocking material may include, for example, a carbazole derivative such as N-phenyl carbazole, polyvinyl carbazole, a fluorene-based derivative, a triphenylamine-based derivative such as N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1-biphenyl]-4,4′-diamine (TPD) or 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), N,N′-di(naphthalene-1-yl)-N,N′-diplienyl-benzidine (NPD), 4,4′-cyclohexylidene bis[N,N-bis(4-methylphenyl)benzenamine] (TAPC), 4,4′-bis[N,N′-(3-tolyl)amino]-3,3′-dimethylbiphenyl (HMTPD), or mCP.

Specifically, the electron blocking material may include a compound represented by Formula 4, but exemplary embodiments of the inventive concepts are not limited thereto:

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In Formula 4,

X₁₁may be selected from O, S, N(R₁₃), and C(R₁₃)(R₁₄),

X₁₂may be selected from a single bond, O, S, N(R₁₅), and C(R₁₅)(R₁₆),

A₁₁and A₁₂may each independently be selected from a C₅-C₆₀carbocyclic group and a C₁-C₆₀heterocyclic group,

R₁₁to R₁₆may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a substituted or unsubstituted C₁-C₆₀alkyl group, a substituted or unsubstituted C₂-C₆₀alkenyl group, a substituted or unsubstituted C₂-C₆₀alkynyl group, a substituted or unsubstituted C₆-C₆₀alkoxy group, a substituted or unsubstituted C_3-10cycloalkyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C_1-10heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀arylthio group, a substituted or unsubstituted C₁-C₆₀heteroaryl group, a substituted or unsubstituted C₁-C₆₀heteroaryloxy group, a substituted or unsubstituted C₁-C₆₀heteroarylthio group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₁)(Q₂)(Q₃), —B(Q₁)(Q₂), —N(Q₁)(Q₂), —P(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)(Q₁), —S(═O)₂(Q₁), —P(═O)(Q₁)(Q₂), and —P(═S)(Q₁)(Q₂),

b11 and b12 may each independently be selected from 1, 2, 3, 4, 5, and 6, and

Q₁to Q₃may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀alkynyl group, a C₁-C₆₀alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀arylthio group, a C₁-C₆₀heteroaryl group, a C₁-C₆₀heteroaryloxy group, a C₁-C₆₀heteroarylthio group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group.

The electron blocking layer may consist of a single compound, or may include a mixture of two or more different compounds.

In one exemplary embodiment, the electron blocking material may be identical to the host, but exemplary embodiments of the inventive concepts are not limited thereto. For example, the electron blocking material may be identical to the hole transport host, but exemplary embodiments of the inventive concepts are not limited thereto.

In one exemplary embodiment, a thickness (D_EB) of the electron blocking layer 131 and a thickness (D_E) of the emission layer 150 may satisfy D_E≥D_EB. Specifically, the thickness (D_EB) of the electron blocking layer 131 and the thickness (D_E) of the emission layer 150 may satisfy D_E>D_EB, but exemplary embodiments of the inventive concepts are not limited thereto. When the thicknesses of the electron blocking layer 131 and the emission layer 150 are within these ranges, the desired efficiency improvement effect may be obtained without increasing the driving voltage of the organic light-emitting device.

In one or more exemplary embodiments, the thickness of the electron blocking layer 131 may be in a range of about 10 Å to about 200 Å, but exemplary embodiments of the inventive concepts are not limited thereto. When the thickness of the electron blocking layer 131 is within this range, the desired efficiency improvement effect may be obtained without increasing the driving voltage of the organic light-emitting device.

When the organic light-emitting device 10 is a full-color organic light-emitting device, the emission layer 150 may be patterned into a red emission layer, a green emission layer, or a blue emission layer, according to a sub-pixel. In one or more exemplary embodiments, the emission layer 150 may have a stacked structure of two or more layers selected from a red emission layer, a green emission layer, and a blue emission layer, in which the two or more layers contact each other or are separated from each other. In one or more exemplary embodiments, the emission layer may include two or more materials selected from a red light-emitting material, a green light-emitting material, and a blue light-emitting material, in which the two or more materials are mixed with each other in a single layer to emit white light.

The emission layer 150 may include a host and a dopant. The dopant may be a phosphorescent dopant. For example, the compound may be a delayed fluorescent dopant.

In one exemplary embodiment, the emission layer 150 may emit green fluorescence or delayed fluorescence, each having a maximum emission wavelength of about 490 nm to about 590 nm.

An amount of the dopant in the emission layer 150 may be in a range of about 0.01 parts by weight to about 15 parts by weight based on 100 parts by weight of the host, but is exemplary embodiments of the inventive concepts are not limited thereto.

A thickness of the emission layer 150 may be in a range of about 100 Å to about 1,000 Å, for example, about 200 Å to about 600 Å. When the thickness of the emission layer 150 within this range, excellent light-emission characteristics may be obtained without a substantial increase in driving voltage.

In one or more exemplary embodiments, the host may include a compound represented by Formula 301 below:

[Ar₃₀₁]_xb11-[(L₃₀₁)_xb1-R₃₀₁]_xb21 <Formula 301>

In Formula 301,

Ar₃₀₁may be a substituted or unsubstituted C₅-C₆₀carbocyclic group or a substituted or unsubstituted C₁-C₆₀heterocyclic group,

xb11 may be 1, 2, or 3,

L₃₀₁may be selected from a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

xb1 may be an integer from 0 to 5,

R₃₀₁may be selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a substituted or unsubstituted C₁-C₆₀alkyl group, a substituted or unsubstituted C₂-C₆₀alkenyl group, a substituted or unsubstituted C₂-C₆₀alkynyl group, a substituted or unsubstituted C₁-C₆₀alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀arylthio group, a substituted or unsubstituted C₁-C₆₀heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃), —N(Q₃₀₁)(Q₃₀₂), —B(Q₃₀₁)(Q₃₀₂), —C(═O)(Q₃₀₁), —S(═O)₂(Q₃₀₁), and —P(═O)(Q₃₀₁)(Q₃₀₂),

xb21 may be an integer from 1 to 5, and

Q₃₀₁to Q₃₀₃may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group, but exemplary embodiments of the inventive concepts are not limited thereto.

In one exemplary embodiment, Ar₃₀₁in Formula 301 may be selected from:

a naphthalene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, an indenoanthracene group, a dibenzofuran group, and a dibenzothiophene group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and

Q₃₁to Q₃₃may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group, but exemplary embodiments of the inventive concepts are not limited thereto.

In Formula 301, when xb11 is two or more, two or more Ar₃₀₁(s) may be linked via a single bond.

In one or more exemplary embodiments, the compound represented by Formula 301 may be represented by Formula 301-1 or 301-2:

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In Formulae 301-1 to 301-2,

A₃₀₁to A₃₀₄may each independently be a benzene group, a naphthalene group, a phenanthrene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a pyridine group, a pyrimidine group, an indene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, an indole group, a carbazole group, a benzocarbazole group, a dibenzocarbazole group, a furan group, a benzofuran group, a dibenzofuran group, a naphthofuran group, a benzonaphthofuran group, a dinaphthofuran group, a thiophene group, a benzothiophene group, a dibenzothiophene group, a naphthothiophene group, a benzonaphthothiophene group, and a dinaphthothiophene group,

X₃₀₁may be O, S, or N-[(L₃₀₄)_Xb4-R₃₀₄],

R₃₁₁to R₃₁₄may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

xb22 and xb23 may each independently be 0, 1, or 2,

L₃₀₁, xb1, R₃₀₁, and Q₃₁to Q₃₃are the same as described above,

L₃₀₂to L₃₀₄may each independently be the same as defined in connection with L₃₀₁,

xb2 to xb4 may each independently be the same as defined in connection with xb1, and

R₃₀₂to R₃₀₄may each independently be the same as defined in connection with R₃₀₁.

For example, in Formulae 301, 301-1, and 301-2, L₃₀₁to L₃₀₄may each independently be selected from:

a phenylene group, a naphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a thiophenylene group, a furanylene group, a carbazolylene group, an indolylene group, an isoindolylene group, a benzofuranylene group, a benzothiophenylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, a dibenzosilolylene group, a pyridinylene group, an imidazolylene group, a pyrazolylene group, a thiazolylene group, an isothiazolylene group, an oxazolylene group, an isoxazolylene group, a thiadiazolylene group, an oxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, a triazinylene group, a quinolinylene group, an isoquinolinylene group, a benzoquinolinylene group, a phthalazinylene group, a naphthyridinylene group, a quinoxalinylene group, a quinazolinylene group, a cinnolinylene group, a phenanthridinylene group, an acridinylene group, a phenanthrolinylene group, a phenazinylene group, a benzimidazolylene group, an isobenzothiazolylene group, a benzoxazolylene group, an isobenzoxazolylene group, a triazolylene group, a tetrazolylene group, an imidazopyridinylene group, an imidazopyrimidinylene group, and an azacarbazolylene group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, an azacarbazolyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B031032), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and

Q₃₁to Q₃₃are the same as described above.

In one exemplary embodiment, R₃₀₁to R₃₀₄in Formulae 301, 301-1, and 301-2 may each independently be selected from:

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and an azacarbazolyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, an azacarbazolyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and

Q₃₁to Q₃₃are the same as described above.

In one or more exemplary embodiments, the host may include an alkaline earth metal complex. For example, the host may be selected from a Be complex (for example, Compound H55), a Mg complex, and a Zn complex.

The host may include at least one selected from 9,10-di(2-naphthyl)anthracene (ADN), 2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN), 9,10-di-(2-naphthyl)-2-t-butyl-anthracene (TBADN), 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), 1,3-di-9-carbazolylbenzene (mCP), 1,3,5-tri(carbazol-9-yl)benzene (TCP), and Compounds H1 to H55, but exemplary embodiments of the inventive concepts are not limited thereto:

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In one exemplary embodiment, the host may include at least one selected from a silicon-containing compound (for example, BCPDS used in the following examples or the like) and a phosphine oxide-containing compound (for example, POPCPA used in the following examples or the like).

However, exemplary embodiments of the inventive concepts are not limited thereto. In one exemplary embodiment, the host may include only one compound, or two or more different compounds (for example, a host used in the following examples includes BCPDS and POPCPA).

The dopant may emit thermally activated delayed fluorescence or fluorescence.

Specifically, the dopant may further satisfy Equation 3:

|S₁(D)−T₁(D)|≤0.5 eV. <Equation 3>

In Equation 3,

T₁(D) is a lowest excitation triplet energy level of the dopant, and

S₁(D) is a lowest excitation singlet energy level of the dopant.

When the dopant satisfies Equation 3, the dopant may emit thermally activated delayed fluorescence or green fluorescence even at room temperature. When the dopant satisfies Equation 3, the dopant may emit green light.

More specifically, the dopant may satisfy |S₁(D)−T₁(D)|≤0.3 eV, but exemplary embodiments of the inventive concepts are not limited thereto.

In one or more exemplary embodiments, the dopant may not include a metal atom. That is, the dopant differs from a phosphorescence emitter including a metal atom.

For example, the dopant may have a D-A type structure including an electron donating group (D) and an electron accepting group (A).

In one exemplary embodiment, the dopant may have a D-A-D type structure or an A-D-A type structure.

In addition, the fluorescent dopant may include an arylamine compound or a styrylamine compound.

The fluorescent dopant may include a compound represented by Formula 501 below:

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In Formula 501,

Ar₅₀₁may be a substituted or unsubstituted C₅-C₆₀carbocyclic group or a substituted or unsubstituted C₁-C₆₀heterocyclic group,

L₅₀₁to L₅₀₃may each independently be selected from a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

xd1 to xd3 may each independently be an integer from 0 to 3,

R₅₀₁and R₅₀₂may each independently be selected from a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀arylthio group, a substituted or unsubstituted C₁-C₆₀heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, and

xd4 may be an integer from 1 to 6.

In one exemplary embodiment, Ar₅₀₁in Formula 501 may be selected from:

a naphthalene group, a heptalene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, an indenoanthracene group, and an indenophenanthrene group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

In one or more exemplary embodiments, L₅₀₁to L₅₀₃in Formula 501 may each independently be selected from:

In one or more exemplary embodiments, R₅₀₁and R₅₀₂in Formula 501 may each independently be selected from:

Q₃₁to Q₃₃may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

In one or more exemplary embodiments, xd4 in Formula 501 may be 2, but exemplary embodiments of the inventive concepts are not limited thereto.

For example, the fluorescent dopant may be selected from Compounds FD1 to FD22:

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In one or more exemplary embodiments, the fluorescent dopant may be selected from the following compounds, but exemplary embodiments of the inventive concepts are not limited thereto:

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The electron transport region 170 may have i) a single-layered structure including a single layer including a single material, ii) a single-layered structure including a single layer including a plurality of different materials, or iii) a multi-layered structure having a plurality of layers including a plurality of different materials.

The electron transport region 170 may include at least one selected from a buffer layer, a hole blocking layer 171, an electron control layer, an electron transport layer 172, and an electron injection layer, but exemplary embodiments of the inventive concepts are not limited thereto.

For example, the electron transport region 170 may have an electron transport layer/electron injection layer structure, an electron transport layer/electron injection layer structure, an electron control layer/electron transport layer/electron injection layer structure, a buffer layer/electron transport layer)/electron injection layer structure, a hole blocking layer/electron transport layer/electron injection layer structure, a hole blocking layer/electron control layer/electron transport layer/electron injection layer structure, or a hole blocking layer/buffer layer/electron transport layer/electron injection layer structure, wherein for each structure, constituting layers are sequentially stacked from the emission layer 150. However, exemplary embodiments of the inventive concepts are not limited thereto.

The hole blocking material included in the hole blocking layer 171 may satisfy 2.5 eV≤T₁(BL)≤3.5 eV, but exemplary embodiments of the inventive concepts are not limited thereto. When the hole blocking material is within this range, excitons may be substantially trapped in the emission layer, and excitons of the emission layer may sufficiently participate in light emission.

The hole blocking material may be represented by Formula 5, but exemplary embodiments of the inventive concepts are not limited thereto:

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In Formula 5,

X₂₁may be N or C(R₂₁), X₂₂may be N or C(R₂₂), X₂₃may be N or C(R₂₃), X₂₄may be N or C(R₂₄), X₂₅may be N or C(R₂₅), and X₂₆may be N or C(R₂₆), wherein at least one selected from X₂₁to X₂₆may be N,

R₂₁to R₂₆may each independently be selected from hydrogen, deuterium, a substituted or unsubstituted C₆-C₆₀aryl group, a substituted or unsubstituted C₁-C₆₀heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, and

at least one selected from R₂₁to R₂₆may each independently be selected from a substituted or unsubstituted C₆-C₆₀aryl group, a substituted or unsubstituted C₁-C₆₀heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group.

In one exemplary embodiment, the hole blocking material may be selected from Compounds 21 to 27, but exemplary embodiments of the inventive concepts are not limited thereto:

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The hole blocking layer 171 may consist of a single compound, or may include a mixture of two or more different compounds.

In one exemplary embodiment, the hole blocking material may be identical to the host, but exemplary embodiments of the inventive concepts are not limited thereto. For example, the hole blocking material may be identical to the electron transport host, but exemplary embodiments of the inventive concepts are not limited thereto.

In one exemplary embodiment, a thickness (D_HB) of the hole blocking layer 171 and a thickness (D_E) of the emission layer 150 may satisfy D_E≥D_HB. Specifically, the thickness (D_HB) of the hole blocking layer 171 and the thickness (D_E) of the emission layer 150 may satisfy D_E>D_HB, but exemplary embodiments of the inventive concepts are not limited thereto. When the thicknesses of the hole blocking layer 171 and the emission layer 150 are within these ranges, the desired efficiency improvement effect may be obtained without increasing the driving voltage of the organic light-emitting device.

In one or more exemplary embodiments, the thickness of the hole blocking layer 171 may be in a range of about 10 Å to about 200 Å, but exemplary embodiments of the inventive concepts are not limited thereto. When the thickness of the hole blocking layer 171 is within this range, the desired efficiency improvement effect may be obtained without increasing the driving voltage of the organic light-emitting device.

The electron transport region 170 (for example, a buffer layer, a hole blocking layer, 171 an electron control layer, or an electron transport layer 172 in the electron transport region) may include a metal-free compound containing at least one π electron-depleted nitrogen-containing ring.

The “π electron-depleted nitrogen-containing ring” indicates a C₁-C₆₀heterocyclic group having at least one *—N═*′ moiety as a ring-forming moiety.

For example, the “π electron-depleted nitrogen-containing ring” may be i) a 5-membered to 7-membered heteromonocyclic group having at least one *—N═*′ moiety, ii) a heteropolycyclic group in which two or more 5-membered to 7-membered heteromonocyclic groups each having at least one *—N═*′ moiety are condensed with each other, or iii) a heteropolycyclic group in which at least one of 5-membered to 7-membered heteromonocyclic groups, each having at least one *—N═*′ moiety, is condensed with at least one C₅-C₆₀carbocyclic group.

Examples of the π electron-depleted nitrogen-containing ring include an imidazole, a pyrazole, a thiazole, an isothiazole, an oxazole, an isoxazole, a pyridine, a pyrazine, a pyrimidine, a pyridazine, an indazole, a purine, a quinoline, an isoquinoline, a benzoquinoline, a phthalazine, a naphthyridine, a quinoxaline, a quinazoline, a cinnoline, a phenanthridine, an acridine, a phenanthroline, a phenazine, a benzimidazole, an isobenzothiazole, a benzoxazole, an isobenzoxazole, a triazole, a tetrazole, an oxadiazole, a triazine, a thiadiazole, an imidazopyridine, an imidazopyrimidine, and an azacarbazole, but are not limited thereto.

For example, the electron transport region 170 may include a compound represented by Formula 601:

[Ar₆₀₁]_xe11-[(L₆₀₁)_xe1-R₆₀₁]_xe21 <Formula 601>

In Formula 601,

Ar₆₀₁may be a substituted or unsubstituted C₅-C₆₀carbocyclic group or a substituted or unsubstituted C₁-C₆₀heterocyclic group,

xe11 may be 1, 2, or 3,

L₆₀₁may be selected from a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

xe1 may be an integer from 0 to 5,

R₆₀₁may be selected from a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀arylthio group, a substituted or unsubstituted C₁-C₆₀heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₆₀₁)(Q₆₀₂)(Q₆₀₃), —C(═O)(Q₆₀₁), —S(═O)₂(Q₆₀₁), and —P(═O)(Q₆₀₁)(Q₆₀₂), and

Q₆₀₁to Q₆₀₃may each independently be a C₁-C₁₀alkyl group, a C₁-C₁₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group, and

xe21 may be an integer from 1 to 5.

In one exemplary embodiment, at least one of Ar₆₀₁(s) in the number of xe11 and R₆₀₁(s) in the number of xe21 may include the π electron-depleted nitrogen-containing ring.

In one exemplary embodiment, Ar₆₀₁in Formula 601 may be selected from:

a benzene group, a naphthalene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, an indenoanthracene group, a dibenzofuran group, a dibenzothiophene group, a carbazole group, an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyrimidine group, a pyridazine group, an indazole group, a purine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a phthalazine group, a naphthyridine group, a quinoxaline group, a quinazoline group, a cinnoline group, a phenanthridine group, an acridine group, a phenanthroline group, a phenazine group, a benzimidazole group, an isobenzothiazole group, a benzoxazole group, an isobenzoxazole group, a triazole group, a tetrazole group, an oxadiazole group, a triazine group, a thiadiazole group, an imidazopyridine group, an imidazopyrimidine group, and an azacarbazole group; and

Q₃₁to Q₃₃may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

When xe11 in Formula 601 is two or more, two or more Ar₆₀₁(s) may be linked via a single bond.

In one or more exemplary embodiments, Ar₆₀₁in Formula 601 may be an anthracene group.

In one or more exemplary embodiments, the compound represented by Formula 601 may be represented by Formula 601-1:

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In Formula 601-1,

X₆₁₄may be N or C(R₆₁₄), X₆₁₅may be N or C(R₆₁₅), and X₆₁₆may be N or C(R₆₁₆), wherein at least one selected from X₆₁₄to X₆₁₆may be N,

L₆₁₁to L₆₁₃may each independently be the same as defined in connection with L₆₀₁,

xe611 to xe613 may each independently be the same as defined in connection with,

R₆₁₁to R₆₁₃may each independently be the same as defined in connection with R₆₀₁, and

R₆₁₄to R₆₁₆may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

In one exemplary embodiment, L₆₀₁and L₆₁₁to L₆₁₃in Formulae 601 and 601-1 may each independently be selected from:

but exemplary embodiments of the inventive concepts are not limited thereto.

In one or more exemplary embodiments, xe1 and xe611 to xe613 in Formulae 601 and 601-1 may each independently be 0, 1, or 2.

In one or more exemplary embodiments, R₆₀₁and R₆₁₁to R₆₁₃in Formulae 601 and 601-1 may each independently be selected from:

—S(═O)₂(Q₆₀₁) and —P(═O)(Q₆₀₁)(Q₆₀₂), and

Q₆₀₁and Q₆₀₂are the same as described above.

The electron transport region 170 may include at least one compound selected from Compounds ET1 to ET36, but exemplary embodiments of the inventive concepts are not limited thereto:

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In one or more exemplary embodiments, the electron transport region 170 may include at least one selected from 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-dphenyl-1,10-phenanthroline (Bphen), Alq₃, BAlq, 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole (TAZ), and NTAZ:

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In one exemplary embodiment, the electron transport region 170 may include a phosphine oxide-containing compound (for example, TSPO1 used in the following examples or the like), but exemplary embodiments of the inventive concepts are not limited thereto. In one exemplary embodiment, the phosphine oxide-containing compound may be used in a hole blocking layer 171 in the electron transport region 170, but exemplary embodiments of the inventive concepts are not limited thereto:

A thicknesses of the buffer layer, the hole blocking layer 171, or the electron control layer may each be in a range of about 20 Å to about 1,000 Å, for example, about 30 Å to about 300 Å. When the thickness of the buffer layer, the hole blocking layer 171, or the electron control layer is within these ranges, excellent electron blocking characteristics or electron control characteristics may be obtained without a substantial increase in driving voltage.

A thickness of the electron transport layer 172 may be in a range of about 100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. When the thickness of the electron transport layer 172 is within the range described above, the electron transport layer 172 may have satisfactory electron transportation characteristics without a substantial increase in driving voltage.

The electron transport region 170 (for example, the electron transport layer 172 in the electron transport region 170) may further include, in addition to the materials described above, a metal-containing material.

The metal-containing material may include at least one selected from alkali metal complex and alkaline earth-metal complex. The alkali metal complex may include a metal ion selected from a Li ion, a Na ion, a K ion, a Rb ion, and a Cs ion, and the alkaline earth-metal complex may include a metal ion selected from a Be ion, a Mg ion, a Ca ion, a Sr ion, and a Ba ion. A ligand coordinated with the metal ion of the alkali metal complex or the alkaline earth-metal complex may be selected from a hydroxy quinoline, a hydroxy isoquinoline, a hydroxy benzoquinoline, a hydroxy acridine, a hydroxy phenanthridine, a hydroxy phenyloxazole, a hydroxy phenylthiazole, a hydroxy diphenyl oxadiazole, a hydroxy diphenylthiadiazole, a hydroxy phenylpyridine, a hydroxy phenylbenzimidazole, a hydroxy phenylbenzothiazole, a bipyridine, a phenanthroline, and a cyclopentadiene, but exemplary embodiments of the inventive concepts are not limited thereto.

For example, the metal-containing material may include a Li complex. The Li complex may include, for example, Compound ET-D1 (lithium quinolate, LiQ) or ET-D2:

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The electron transport region 170 may include an electron injection layer that facilitates injection of electrons from the second electrode 190. The electron injection layer may directly contact the second electrode 190.

The electron injection layer may have i) a single-layered structure including a single layer including a single material, ii) a single-layered structure including a single layer including a plurality of different materials, or iii) a multi-layered structure having a plurality of layers including a plurality of different materials.

The electron injection layer may include an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth-metal compound, a rare earth metal compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combinations thereof.

The alkali metal may be selected from Li, Na, K, Rb, and Cs. In one exemplary embodiment, the alkali metal may be Li, Na, or Cs. In one or more exemplary embodiments, the alkali metal may be Li or Cs, but exemplary embodiments of the inventive concepts are not limited thereto.

The alkaline earth metal may be selected from Mg, Ca, Sr, and Ba.

The rare earth metal may be selected from Sc, Y, Ce, Tb, Yb, and Gd.

The alkali metal compound, the alkaline earth-metal compound, and the rare earth metal compound may be selected from oxides and halides (for example, fluorides, chlorides, bromides, or iodides) of the alkali metal, the alkaline earth-metal, and the rare earth metal.

The alkali metal compound may be selected from alkali metal oxides, such as Li₂O, Cs₂O, or K₂O, and alkali metal halides, such as LiF, NaF, CsF, KF, LiI, NaI, CsI, or KI. In one exemplary embodiment, the alkali metal compound may be selected from LiF, Li₂O, NaF, LiI, NaI, CsI, and KI, but exemplary embodiments of the inventive concepts are not limited thereto.

The alkaline earth-metal compound may be selected from alkaline earth-metal oxides, such as BaO, SrO, CaO, Ba_xSr_1−xO (0<x<1), or Ba_xCa_1−xO (0<x<1). In one exemplary embodiment, the alkaline earth-metal compound may be selected from BaO, SrO, and CaO, but exemplary embodiments of the inventive concepts are not limited thereto.

The rare earth metal compound may be selected from YbF₃, ScF₃, ScO₃, Y₂O₃, Ce₂O₃, GdF₃, and TbF₃. In one exemplary embodiment, the rare earth metal compound may be selected from YbF₃, ScF₃, TbF₃, YbI₃, ScI₃, and TbI₃, but exemplary embodiments of the inventive concepts are not limited thereto.

The alkali metal complex, the alkaline earth-metal complex, and the rare earth metal complex may include an ion of alkali metal, alkaline earth-metal, and rare earth metal as described above, and a ligand coordinated with a metal ion of the alkali metal complex, the alkaline earth-metal complex, or the rare earth metal complex may be selected from hydroxy quinoline, hydroxy isoquinoline, hydroxy benzoquinoline, hydroxy acridine, hydroxy phenanthridine, hydroxy phenyloxazole, hydroxy phenylthiazole, hydroxy diphenyl oxadiazole, hydroxy diphenylthiadiazole, hydroxy phenylpyridine, hydroxy phenylbenzimidazole, hydroxy phenylbenzothiazole, bipyridine, phenanthroline, and cyclopentadiene, but exemplary embodiments of the inventive concepts are not limited thereto.

The electron injection layer may consist of an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth-metal compound, a rare earth metal compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combinations thereof, as described above. In one or more exemplary embodiments, the electron injection layer may further include an organic material. When the electron injection layer further includes an organic material, an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth-metal compound, a rare earth metal compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combinations thereof may be homogeneously or non-homogeneously dispersed in a matrix including the organic material.

A thickness of the electron injection layer may be in a range of about 1 Å to about 100 Å, for example, about 3 Å to about 90 Å. When the thickness of the electron injection layer is within the range described above, the electron injection layer may have satisfactory electron injection characteristics without a substantial increase in driving voltage.

As described above, the organic light-emitting device 10 may include the first auxiliary layer 160, and the organic light-emitting device 20 may include the first auxiliary layer 160 and the second auxiliary layer 140.

The first auxiliary layer 160 may include a first compound. When the host included in the emission layer 150 and the first compound are identical to each other, the first auxiliary layer 160 consists of the first compound only. For example, the first auxiliary layer 160 may consist of the first compound only.

The first compound may be represented by one selected from Formulae 1 to 3:

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In Formulae 1 to 3,

Ar₁may be a substituted or unsubstituted C₅-C₆₀carbocyclic group or a substituted or unsubstituted C₁-C₆₀heterocyclic group,

a1 may be 1, 2, or 3,

a11 may be an integer from 0 to 5,

b11 to b14 may each independently be an integer from 0 to 3,

b15 may be an integer from 1 to 10,

R₁₁to R₁₄and Q″ may each independently be selected from a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀arylthio group, a substituted or unsubstituted C₁-C₆₀heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group,

a21 may be an integer from 1 to 5, and

Q₁to Q₃may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

For example, Ar₁may be selected from a carbazole group, a benzocarbazole group, a dibenzocarbazole group, an indole group, a benzoindole group, a dibenzoindole group, a triazine group, a furan group, an acridine group, a phenoxazine group, and a phenothiazine group; and

Q₃₁to Q₃₃may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

The second auxiliary layer 140 may include the second compound. When the host included in the emission layer 150 is identical to the second compound, the second auxiliary layer 140 may consist of the second compound only. For example, the second auxiliary layer 140 may consist of the second compound only.

The second compound may be the same as defined in connection with the first compound.

The second electrode 190 may be disposed on the organic layer having such a structure. The second electrode 190 may be a cathode which is an electron injection electrode, and in this regard, a material for forming the second electrode 190 may be selected from metal, an alloy, an electrically conductive compound, and a combination thereof, which have a relatively low work function.

The second electrode 190 may include at least one selected from lithium (Li), silver (Ag), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), ITO, and IZO, but exemplary embodiments of the inventive concepts are not limited thereto. The second electrode 190 may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode.

The second electrode 190 may have a single-layered structure, or a multi-layered structure including two or more layers.

The organic light-emitting devices 10 and 20 may each further include a capping layer in a direction in which light is extracted. The capping layer may increase external luminescence efficiency according to the principle of constructive interference.

The capping layer may be an organic capping layer including an organic material, an inorganic capping layer including an inorganic material, or a composite capping layer including an organic material and an inorganic material.

The capping layer may include at least one material selected from carbocyclic compounds, heterocyclic compounds, amine-based compounds, porphine derivatives, phthalocyanine derivatives, naphthalocyanine derivatives, an alkali metal complexes, and alkaline earth-metal complexes. The carbocyclic compound, the heterocyclic compound, and the amine-based compound may be optionally substituted with a substituent containing at least one element selected from O, N, S, Se, Si, F, Cl, Br, and I.

In one exemplary embodiment, the capping layer may include the amine-based compound.

In one or more exemplary embodiments, the capping layer may include a compound represented by Formula 201 or Formula 202.

In one or more exemplary embodiments, the capping layer may include a compound selected from Compounds HT28 to HT33 and Compounds CP1 to CP5, but exemplary embodiments of the inventive concepts are not limited thereto:

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Hereinbefore, the organic light-emitting device according to an exemplary embodiment has been described in connection with FIGS. 1 and 2. However, exemplary embodiments of the inventive concepts are not limited thereto.

Layers constituting the hole transport region, an emission layer, and layers constituting the electron transport region may be formed in a certain region by using one or more suitable methods selected from vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) deposition, ink-jet printing, laser-printing, and laser-induced thermal imaging.

When layers constituting the hole transport region, an emission layer, and layers constituting the electron transport region are formed by vacuum deposition, the deposition may be performed at a deposition temperature of about 100° C. to about 500° C., a vacuum degree of about 10⁻⁸torr to about 10⁻³torr, and a deposition speed of about 0.01 Å/sec to about 100 Å/sec by taking into account a material to be included in a layer to be formed, and the structure of a layer to be formed.

When layers constituting the hole transport region, an emission layer, and layers constituting the electron transport region are formed by spin coating, the spin coating may be performed at a coating speed of about 2,000 rpm to about 5,000 rpm and at a heat treatment temperature of about 80° C. to 200° C. by taking into account a material to be included in a layer to be formed, and the structure of a layer to be formed.

The term “C₁-C₆₀alkyl group” as used herein refers to a linear or branched aliphatic saturated hydrocarbon monovalent group having 1 to 60 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isoamyl group, and a hexyl group. The term “C₁-C₆₀alkylene group” as used herein refers to a divalent group having the same structure as the C₁-C₆₀alkyl group.

The term “C₂-C₆₀alkenyl group” as used herein refers to a hydrocarbon group having at least one carbon-carbon double bond in the middle or at the terminus of the C₂-C₆₀alkyl group, and examples thereof include an ethenyl group, a propenyl group, and a butenyl group. The term “C₂-C₆₀alkenylene group” as used herein refers to a divalent group having the same structure as the C₂-C₆₀alkenyl group.

The term “C₂-C₆₀alkynyl group” as used herein refers to a hydrocarbon group having at least one carbon-carbon triple bond in the middle or at the terminus of the C₂-C₆₀alkyl group, and examples thereof include an ethynyl group, and a propynyl group. The term “C₂-C₆₀alkynylene group” as used herein refers to a divalent group having the same structure as the C₂-C₆₀alkynyl group.

The term “C₁-C₆₀alkoxy group” as used herein refers to a monovalent group represented by —OA₁₀₁(wherein A₁₀₁is the C₁-C₆₀alkyl group), and examples thereof include a methoxy group, an ethoxy group, and an isopropyloxy group.

The term “C₃-C₁₀cycloalkyl group” as used herein refers to a monovalent saturated hydrocarbon monocyclic group having 3 to 10 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. The term “C₃-C₁₀cycloalkylene group” as used herein refers to a divalent group having the same structure as the C₃-C₁₀cycloalkyl group.

The term “C₁-C₁₀heterocycloalkyl group” as used herein refers to a monovalent monocyclic group having at least one heteroatom selected from N, O, Si, P, and S as a ring-forming atom and 1 to 10 carbon atoms, and examples thereof include a 1,2,3,4-oxatriazolidinyl group, a tetrahydrofuranyl group, and a tetrahydrothiophenyl group. The term “C₁-C₁₀heterocycloalkylene group” as used herein refers to a divalent group having the same structure as the C₁-C₁₀heterocycloalkyl group.

The term “C₃-C₁₀cycloalkenyl group” as used herein refers to a monovalent monocyclic group that has 3 to 10 carbon atoms and at least one carbon-carbon double bond in the ring thereof and no aromaticity, and examples thereof include a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. The term “C₃-C₁₀cycloalkenylene group” as used herein refers to a divalent group having the same structure as the C₃-C₁₀cycloalkenyl group.

The term “C₁-C₁₀heterocycloalkenyl group” as used herein refers to a monovalent monocyclic group that has at least one heteroatom selected from N, O, Si, P, and S as a ring-forming atom, 1 to 10 carbon atoms, and at least one carbon-carbon double bond in its ring. Non-limiting examples of the C₁-C₁₀heterocycloalkenyl group include a 4,5-dihydro-1,2,3,4-oxatriazolyl group, a 2,3-dihydrofuranyl group, and a 2,3-dihydrothiophenyl group. The term “C₁-C₁₀heterocycloalkenylene group” as used herein refers to a divalent group having the same structure as the C₁-C₁₀heterocycloalkenyl group.

The term “C₆-C₆₀aryl group” as used herein refers to a monovalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms, and a C₆-C₆₀arylene group used herein refers to a divalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms. Non-limiting examples of the C₆-C₆₀aryl group include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, and a chrysenyl group. When the C₆-C₆₀aryl group and the C₆-C₆₀arylene group each include two or more rings, the rings may be fused to each other.

The term “C₁-C₆₀heteroaryl group” as used herein refers to a monovalent group having a carbocyclic aromatic system that has at least one heteroatom selected from N, O, Si, P, and S as a ring-forming atom, in addition to 1 to 60 carbon atoms. The term “C₁-C₆₀heteroarylene group” as used herein refers to a divalent group having a carbocyclic aromatic system that has at least one heteroatom selected from N, O, Si, P, and S as a ring-forming atom, in addition to 1 to 60 carbon atoms. Non-limiting examples of the C₁-C₆₀heteroaryl group include a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, and an isoquinolinyl group. When the C₁-C₆₀heteroaryl group and the C₁-C₆₀heteroarylene group each include two or more rings, the rings may be condensed with each other.

The term “C₆-C₆₀aryloxy group” as used herein refers to —OA₁₀₂(wherein A₁₀₂is the C₆-C₆₀aryl group), and a C₆-C₆₀arylthio group used herein indicates —SA₁₀₃(wherein A₁₀₃is the C₆-C₆₀aryl group).

The term “monovalent non-aromatic condensed polycyclic group” as used herein refers to a monovalent group (for example, having 8 to 60 carbon atoms) having two or more rings condensed with each other, only carbon atoms as ring-forming atoms, and no aromaticity in its entire molecular structure. A detailed example of the monovalent non-aromatic condensed polycyclic group is a fluorenyl group. The term “divalent non-aromatic condensed polycyclic group” as used herein refers to a divalent group having the same structure as the monovalent non-aromatic condensed polycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group” as used herein refers to a monovalent group (for example, having 1 to 60 carbon atoms) having two or more rings condensed to each other, at least one heteroatom selected from N, O, Si, P, and S, other than carbon atoms, as a ring-forming atom, and no aromaticity in its entire molecular structure. An example of the monovalent non-aromatic condensed heteropolycyclic group is a carbazolyl group. The term “divalent non-aromatic condensed heteropolycyclic group” as used herein refers to a divalent group having the same structure as the monovalent non-aromatic condensed heteropolycyclic group.

The term “C₄-C₆₀carbocyclic group” as used herein refers to a monocyclic or polycyclic group having 4 to 60 carbon atoms in which a ring-forming atom is a carbon atom only. The term “C₄-C₆₀carbocyclic group” as used herein refers to an aromatic carbocyclic group or a non-aromatic carbocyclic group. The C₄-C₆₀carbocyclic group may be a ring, such as benzene, a monovalent group, such as a phenyl group, or a divalent group, such as a phenylene group. In one or more exemplary embodiments, depending on the number of substituents connected to the C₄-C₆₀carbocyclic group, the C₄-C₆₀carbocyclic group may be a trivalent group or a quadrivalent group.

The term “C₂-C₆₀heterocyclic group” as used herein refers to a group having the same structure as the C₄-C₆₀carbocyclic group, except that as a ring-forming atom, at least one heteroatom selected from N, O, Si, P, and S is used in addition to carbon (the number of carbon atoms may be in a range of 2 to 60).

In the present specification, at least one substituent of the substituted C₄-C₆₀carbocyclic group, the substituted C₂-C₆₀heterocyclic group, the substituted C₃-C₁₀cycloalkylene group, the substituted C₁-C₁₀heterocycloalkylene group, the substituted C₃-C₁₀cycloalkenylene group, the substituted C₁-C₁₀heterocycloalkenylene group, the substituted C₆-C₆₀arylene group, the substituted C₁-C₆₀heteroarylene group, the substituted divalent non-aromatic condensed polycyclic group, the substituted divalent non-aromatic condensed heteropolycyclic group, the substituted C₁-C₆₀alkyl group, the substituted C₂-C₆₀alkenyl group, the substituted C₂-C₆₀alkynyl group, the substituted C₁-C₆₀alkoxy group, the substituted C₃-C₁₀cycloalkyl group, the substituted C₁-C₁₀heterocycloalkyl group, the substituted C₃-C₁₀cycloalkenyl group, the substituted C₁-C₁₀heterocycloalkenyl group, the substituted C₆-C₆₀aryl group, the substituted C₆-C₆₀aryloxy group, the substituted C₆-C₆₀arylthio group, the substituted C₁-C₆₀heteroaryl group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group may each independently be selected from:

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀alkynyl group, and a C₁-C₆₀alkoxy group;

a C₁-C₆₀alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀alkynyl group, and a C₁-C₆₀alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₁₁)(Q₁₂)(Q₁₃), —, N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁), —S(═O)₂(Q₁₁), and —P(═O)(Q₁₁)(Q₁₂);

a C₃-C₁₀cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀alkynyl group, a C₁-C₆₀alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and —P(═O)(Q₂₁)(Q₂₂); and

—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and

Q_1′to Q₁₃, Q₂₁to Q₂₃, and Q₃₁to Q₃₃may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀alkynyl group, a C₁-C₆₀alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀aryl group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a C₁-C₆₀alkyl group substituted with at least one selected from deuterium, —F, and a cyano group, a C₆-C₆₀aryl group substituted with at least one selected from deuterium, —F, and a cyano group, a biphenyl group, and a terphenyl group.

The term “Ph” as used herein refers to a phenyl group, the term “Me” as used herein refers to a methyl group, the term “Et” as used herein refers to an ethyl group, the term “ter-Bu” or “Bu^t” as used herein refers to a tert-butyl group, and the term “OMe” as used herein refers to a methoxy group.

The term “biphenyl group” as used herein refers to “a phenyl group substituted with a phenyl group.” In other words, the “biphenyl group” is a substituted phenyl group having a C₆-C₆₀aryl group as a substituent.

The term “terphenyl group” as used herein refers to “a phenyl group substituted with a biphenyl group.” In other words, the “terphenyl group” is a phenyl group having, as a substituent, a C₆-C₆₀aryl group substituted with a C₆-C₆₀aryl group.

* and *′ as used herein, unless defined otherwise, each refer to a binding site to a neighboring atom in a corresponding formula.

Hereinafter, an organic light-emitting device according to an exemplary embodiment will be described in detail with reference to Synthesis Examples and Examples.

Evaluation Example 1: Measurement of Lowest Excitation Triplet Energy Level (T1)

The lowest excitation triplet energy levels (T1) of the host, the first compound, and the second compound were measured by using a DFT method of Gaussian program structurally optimized at a level of B3LYP/6-31G(d,p), and results thereof are shown in Table 1 below.

TABLE 1

Material
T1 (eV)

Host (CBP)
2.65

First compound
2.50

Second compound
2.57

Example 1

As a substrate and an anode, a glass substrate with 15 Ω/cm2 (1,200 Å) ITO thereon, which was manufactured by Corning Inc., was cut to a size of 50 mm×50 mm×0.5 mm, sonicated with isopropyl alcohol and pure water each for 5 minutes, and then cleaned by exposure to ultraviolet rays and ozone for 30 minutes. Then, the resultant glass substrate was loaded onto a vacuum deposition apparatus.

2-TNATA was vacuum-deposited on the ITO glass substrate to form a hole injection layer having a thickness of 200 Å, and NPB was vacuum-deposited on the hole injection layer to form a hole transport layer having a thickness of 400 Å.

CBP was vacuum-deposited on the hole transport layer to form an electron blocking layer having a thickness of 100 Å.

CBP (host) and 4CzIPN (dopant) were co-deposited on the electron blocking layer at a weight ratio of 80:20 to form an emission layer having a thickness of 300 Å.

A first compound was vacuum-deposited on the emission layer to form a first auxiliary layer having a thickness of 50 Å.

TPBi was vacuum-deposited on the first auxiliary layer to form a hole blocking layer having a thickness of 100 Å.

Alq₃was vacuum-deposited on the hole blocking layer to form an electron transport layer having a thickness of 300 Å. LiQ was vacuum-deposited on the electron transport layer to form an electron injection layer having a thickness of 10 Å, and Al was vacuum-deposited to form a cathode having a thickness of 2,000 Å, thereby completing the manufacture of an organic light-emitting device.

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4CzIPN TPBi

Example 2

As a substrate and an anode, a glass substrate with 15 Ω/cm²(1,200 Å) ITO thereon, which was manufactured by Corning Inc., was cut to a size of 50 mm×50 mm×0.5 mm, sonicated with isopropyl alcohol and pure water each for 5 minutes, and then cleaned by exposure to ultraviolet rays and ozone for 30 minutes. Then, the resultant glass substrate was loaded onto a vacuum deposition apparatus.

CBP was vacuum-deposited on the hole transport layer to form an electron blocking layer having a thickness of 100 Å.

A second compound was vacuum-deposited on the electron blocking layer to form a second auxiliary layer having a thickness of 50 Å.

CBP (host) and 4CzIPN (dopant) were co-deposited on the second auxiliary layer at a weight ratio of 80:20 to form an emission layer having a thickness of 300 Å.

A first compound was vacuum-deposited on the emission layer to form a first auxiliary layer having a thickness of 50 Å.

TPBi was vacuum-deposited on the first auxiliary layer to form a hole blocking layer having a thickness of 100 Å.

Comparative Example 1

An organic light-emitting device was manufactured in the same manner as in Example 1, except that CBP and Alq₃were vacuum-deposited on an emission layer at a weight ratio of 50:50 to form a first auxiliary layer having a thickness of 50 Å.

Comparative Example 2

An organic light-emitting device was manufactured in the same manner as in Example 1, except that the hole blocking layer was not disposed on the first auxiliary layer.

Comparative Example 3

An organic light-emitting device was manufactured in the same manner as in Example 1, except that the first auxiliary layer was not disposed on the emission layer.

Evaluation Example 2

The driving voltage, current efficiency, and lifespan of the organic light-emitting devices manufactured according to Examples 1 and 2 and Comparative Examples 1 to 3 were measured by using Keithley SMU 236 and a luminance meter PR650, and results thereof are shown in Table 2 and FIG. 3.

TABLE 2

Driving
Current

voltage
efficiency
Lifespan

(V)
(Cd/A)
(hr)
Remark

Example 1
100%
118%
147%
—

Example 2
100%
114%
135%
—

Comparative
120%
80%
85%
—

Example 1

Comparative
115%
75%
80%
—

Example 2

Comparative
100%
100%
100%
Standard

Example 3

From Table 2 and FIG. 3, it is confirmed that the organic light-emitting devices of Examples 1 and 2 have high efficiency and a long lifespan, as compared with those of the organic light-emitting devices of Comparative Examples 1 to 3.

The organic light-emitting device which includes the host and the first compound satisfying the lowest excitation triplet energy level relationship and in which the auxiliary layer including the first compound is disposed in the emission layer and the hole blocking layer may have a long lifespan and high efficiency.

Although certain exemplary embodiments and implementations have been described herein, other embodiments and modifications will be apparent from this description. Accordingly, the inventive concepts are not limited to such embodiments, but rather to the broader scope of the appended claims and various obvious modifications and equivalent arrangements as would be apparent to a person of ordinary skill in the art.

ORGANIC LIGHT-EMITTING DEVICE

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