HETEROCYCLIC COMPOUND AND ORGANIC LIGHT-EMITTING DEVICE INCLUDING THE SAME

An organic light-emitting device includes a heterocyclic compound represented by Formula 1, in which at least one of X1 to X4 is a nitrogen atom, and at least one is carbon atom substituted by Formula 1A:   The heterocyclic compound represented by Formula 1 may have excellent electron transport capability, and the organic light-emitting device may accordingly have low driving voltage, high efficiency, high luminance, and/or long lifespan characteristics.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2020-0062643, filed on May 25, 2020, in the Korean Intellectual Property Office, the entire content of which is incorporated herein by reference.

BACKGROUND

One or more aspects of embodiments of the present disclosure relate to a heterocyclic compound and an organic light-emitting device including the same.

2. Description of Related Art

Organic light-emitting devices (OLEDs) are self-emission devices that may produce full-color images, and may also have wide viewing angles, high contrast ratios, short response times, and/or excellent characteristics in terms of brightness, driving voltage, and/or response speed.

SUMMARY

One or more aspects of embodiments of the present disclosure are directed toward a novel heterocyclic compound and an organic light-emitting device including the same.

One or more example embodiments of the present disclosure provide a heterocyclic compound (for example, a heterocyclic aromatic compound) represented by Formula 1:

A1may be selected from a C5-C60carbocyclic group and a C1-C60heterocyclic group,

X1may be N or C(R1), X2may be N or C(R2), X3may be N or C(R3), X4may be N or C(R4), and at least one of X1to X4may be N,

L1to L3may each independently be selected from a C5-C60carbocyclic group and a C1-C60heterocyclic group,

a1 to a3 may each independently be an integer from 0 to 4, wherein, when a1 is 2 or more, two or more L1(s) are identical to or different from each other, when a2 is 2 or more, two or more L2(s) are identical to or different from each other, and when a3 is 2 or more, two or more L3(s) are identical to or different from each other,

when a1 is 0, *′-L1-*″ is a single bond, when a2 is 0, *′-L2-*″ is a single bond, and when a3 is 0, *′-L3-*″ is a single bond,

Ar1and Ar2may each independently be selected from a C5-C60carbocyclic group and a C1-C60heterocyclic group,

b1 and b2 may each independently be an integer from 1 to 4,

c1 may be an integer from 0 to 10,

where at least one of R1to R4is a group represented by Formula 1A,

t may be an integer from 1 to 5,

* indicates a binding site to Formula 1, and

*′ and *″ each indicate a binding site to an adjacent group.

One or more example embodiments of the present disclosure provide an organic light-emitting device including a first electrode, a second electrode facing the first electrode, and an organic layer located between the first electrode and the second electrode and including an emission layer, wherein the organic layer includes at least one heterocyclic compound represented by Formula 1.

DETAILED DESCRIPTION

As the present disclosure can undergo various transformations and can have various examples, selected examples will be illustrated in the drawings and described in more detail in the detailed description. Effects and features of the present disclosure, and methods of achieving the same will be clarified by referring to the detailed Examples with reference to the drawings. However, the present disclosure is not limited to the examples disclosed below and may be implemented in various forms.

It will be further understood that the terms “includes,” “including,” “comprises,” and/or “comprising,” used herein specify the presence of stated features or components, but do not preclude the presence or addition of one or more other features or components. Further, the use of “may” when describing embodiments of the present disclosure refers to “one or more embodiments of the present disclosure”.

It will be understood that when a layer, region, or component is referred to as being “on” or “onto” another layer, region, or component, it may be directly or indirectly formed on the other layer, region, or component. That is, for example, intervening layers, regions, or components may be present. When an element is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element, there are no intervening elements present.

Sizes and dimensions of elements in the drawings may be exaggerated for convenience of explanation. For example, because sizes and thicknesses of components in the drawings are arbitrarily illustrated for convenience of explanation, the following embodiments of the present disclosure are not limited thereto.

The term “organic layer” as used herein may refer to a single layer and/or a plurality of layers disposed between the first electrode and the second electrode of the organic light-emitting device. Materials included in the “organic layer” are not limited to being an organic material.

One or more example embodiments of the present disclosure provide a heterocyclic compound represented by Formula 1:

wherein, A1in Formula 1 may be selected from a C5-C60carbocyclic group and a C1-C60heterocyclic group.

In an embodiment, A1may be selected from a C6-C60aryl group, a C2-C60heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group.

In Formula 1, X1may be N or C(R1), X2may be N or C(R2), X3may be N or C(R3), X4may be N or C(R4), and at least one of X1to X4may be N.

In an embodiment, two or more of X1to X4may each be N.

In one or more embodiments, two of X1to X4may each be N.

In an embodiment, X1and X3may each be N, X2may be C(R2), and X4may be C(R4), and one of R2and R4may be a group represented by Formula 1A, and the other may be a substituted or unsubstituted C6-C60aryl group.

In one or more embodiments, X1and X4may each be N, X2may be C(R2), and X3may be C(R3), and one of R2and R3may be a group represented by Formula 1A, and the other may be a substituted or unsubstituted C6-C60aryl group.

In one or more embodiments, X2and X3may each be N, X1may be C(R1), and X4may be C(R4), and one of R1and R4may be a group represented by Formula 1A, and the other may be a substituted or unsubstituted C6-C60aryl group.

In one or more embodiments, X1and X2may each be N, X3may be C(R3), and X4may be C(R4), and one of R3and R4may be a group represented by Formula 1A, and the other may be a substituted or unsubstituted C6-C60aryl group.

In Formula 1, L1to L3may each independently be selected from a C5-C60carbocyclic group and a C1-C60heterocyclic group.

In an embodiment, L1to L3may each independently be selected from:

Q31to Q33may each independently be selected from a C1-C20alkyl group, a C1-C20alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, and a pyridinyl group.

For example, L2and L3may each independently be selected from:

Q31to Q33may each independently be selected from a C1-C20alkyl group, a C1-C20alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, and a pyridinyl group.

In some embodiments, L2and L3may be different from each other.

In Formulae 1 and 1A, a1 to a3 may each independently be an integer from 0 to 4, wherein, when a1 is 2 or more, two or more L1(s) may be identical to or different from each other; when a2 is 2 or more, two or more L2(s) may be identical to or different from each other; when a3 is 2 or more, two or more L3(s) may be identical to or different from each other when a1 is 0, *′-L1-*″ may be a single bond; when a2 is 0, *′-L2-*″ may be a single bond; and when a3 is 0, *′-L3-*″ may be a single bond.

In an embodiment, a1 may be an integer from 0 to 4, and a2 and a3 may each independently be an integer from 1 to 4.

In an embodiment, a2+a3≥3.

In Formulae 1 and 1A, Ar1and Ar2may each independently be selected from a C5-C60carbocyclic group and a C1-C60heterocyclic group.

In an embodiment, Ar1and Ar2may each independently be selected from a substituted or unsubstituted C6-C60aryl group, a substituted or unsubstituted C2-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, Ar1and Ar2may each independently be selected from a substituted or unsubstituted C6-C60aryl group and a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group.

For example, Ar1and Ar2may each independently be selected from:

In Formulae 1 and 1A, b1 and b2 may each independently be an integer from 1 to 4.

In Formula 1, c1 may be an integer from 0 to 10.

In an embodiment, c1 may be 0.

In an embodiment, R1to R4may each independently be selected from groups represented by Formulae 1A and 3-1 to 3-19:

In Formulae 3-1 to 3-19,

e3 may be an integer from 0 to 3,

e4 may be an integer from 0 to 4,

e5 may be an integer from 0 to 5,

e6 may be an integer from 0 to 6,

e7 may be an integer from 0 to 7,

e9 may be an integer from 0 to 9, and

* indicates a binding site to a neighboring atom.

For example, in Formulae 3-1 to 3-19, Z31to Z36may each independently be selected from hydrogen, deuterium, a cyano group, a C1-C20alkyl group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, and a pyrenyl group.

In Formula 1, t may be an integer from 1 to 5.

In an embodiment, t may be an integer from 1 to 3.

In an embodiment, Formula 1A may be represented by Formula 1A-1 or 1A-2:

L10, L11, and L12may each independently be the same as described in connection with L2,

Ar21may be the same as described in connection with Ar2,

t may be the same as described above,

f10, f11, f12, and f21 may each independently be an integer from 0 to 10.

For example, in Formulae 1A-1 and 1A-2,

Ar21may be selected from a benzene group, a naphthalene group, an anthracene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, and a perylene group,

t may be an integer from 1 to 3,

f10, f11, f12, and f21 may each independently be an integer from 0 to 10.

In one or more embodiments, Formula 1A may be represented by Formula 1A-1-1 or 1A-2-1:

L10and L12may each independently be the same as described in connection with L2,

Ar21may be the same as described in connection with Ar2,

t may be the same as described above,

f10, f11, f12, and f21 may each independently be an integer from 0 to 10.

In an embodiment, c1 may be 0, a2 and a3 may each independently be an integer from 1 to 4, a2+a3 may be 2 or 3, b2 may be 1, and t may be 1, 2, or 3.

The heterocyclic compound represented by Formula 1 may be selected from Compounds 1 to 66:

The heterocyclic compound represented by Formula 1 may have improved electron transport characteristics due to having a structure in which a group represented by Formula 1A is bonded to a heterocyclic core including at least one N atom in a condensed ring as represented by Formula 1, so that electrical stress is weakened in the movement of electrons (e.g., electron transport barriers are decreased), thereby enabling a device including the heterocyclic compound to exhibit high efficiency and/or long lifespan characteristics.

In addition, the heterocyclic compound represented by Formula 1 may have improved electron transport characteristics due to having a structure in which at least one group represented by Formula 1A includes a cyano group substituent, thereby enabling improved hole-electron balance and accordingly high efficiency characteristics in an OLED.

In addition, in the substituents represented by Formula 1A in the heterocyclic compound represented by Formula 1, a2+a3>2, and b2 may be an integer from 1 to 4. For example, because the heterocyclic compound represented by Formula 1 includes a plurality of aromatic rings, the conjugated structure is enlarged and the stability of the compound is improved. In addition, because the compound accordingly has a molecular structure in the long-axis direction (e.g., the compound structure is elongated along at least one axis), the compound may have an advantageous effect in terms of molecular orientation (e.g., when deposited as a film in a device), thereby enabling long lifespan characteristics.

In addition, in the substituents represented by Formula 1A in the heterocyclic compound represented by Formula 1, L2, L3, and Ar2are all connected via C—C single bonds, which contributes to improved structural stability and consequently improves the lifespan of a device including the heterocyclic compound.

A synthesis method for the heterocyclic compound represented by Formula 1 may be understood by those of ordinary skill in the art by referring to the following examples.

At least one heterocyclic compound represented by Formula 1 may be used between a pair of electrodes in an organic light-emitting device. For example, the heterocyclic compound represented by Formula 1 may be included in at least one selected from a hole transport region, an electron transport region, and an emission layer. In one or more embodiments, the heterocyclic compound represented by Formula 1 may be used as a material for a capping layer located outside a pair of electrodes of an organic light-emitting device.

One or more example embodiments of the present disclosure provide an organic light-emitting device including: a first electrode; a second electrode facing the first electrode; an organic layer located between the first electrode and the second electrode and including an emission layer; and at least one heterocyclic compound represented by Formula 1.

In an embodiment, the organic layer of the organic light-emitting device may include the heterocyclic compound represented by Formula 1.

In an embodiment, the first electrode may be an anode,

the second electrode may be a cathode,

the organic layer may include the heterocyclic compound represented by Formula 1,

the organic layer may further include a hole transport region located between the first electrode and the emission layer and an electron transport region located between the emission layer and the second electrode,

the electron transport region may include a buffer layer, a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

In an embodiment, the electron transport region of the organic light-emitting device may include the heterocyclic compound represented by Formula 1. In one or more embodiments, the electron transport region may further include a metal-containing material.

In one or more embodiments, the electron transport region may include an electron transport layer, and the electron transport layer may include at least one heterocyclic compound represented by Formula 1.

In an embodiment, the emission layer may be a first-color-light emission layer to emit first-color-light,

the organic light-emitting device may further include, between the first electrode and the second electrode, i) at least one second-color-light emission layer to emit second-color-light or ii) at least one second-color-light emission layer to emit second-color-light and at least one third-color-light emission layer to emit third-color light,

a maximum luminescence wavelength of the first-color light, a maximum luminescence wavelength of the second-color light, and a maximum luminescence wavelength of the third-color light may be identical to or different from each other, and

the first-color light and the second-color light may be emitted in the form of mixed light, or the first-color light, the second-color light, and the third-color light may be emitted in the form of mixed light.

One or more example embodiments of the present disclosure provide an electronic apparatus: including the organic light-emitting device; and a thin-film transistor, wherein the first electrode of the organic light-emitting device electrically contacts one of a source electrode and a drain electrode of the thin-film transistor.

FIG. 1is a schematic cross-sectional view of an organic light-emitting device10according to an embodiment. The organic light-emitting device10includes a first electrode110, an organic layer150, and a second electrode190.

Hereinafter, the structure of the organic light-emitting device10according to an embodiment and a method of manufacturing the organic light-emitting device10will be described in connection withFIG. 1.

InFIG. 1, a substrate may be additionally located under the first electrode110or above the second electrode190. The substrate may be a glass substrate and/or a plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and/or water resistance.

The first electrode110may be formed by, for example, depositing or sputtering a material for forming the first electrode110on the substrate. When the first electrode110is an anode, the material for forming the first electrode110may be selected from materials with a high work function to facilitate hole injection.

The organic layer150is located on the first electrode110. The organic layer150may include an emission layer.

The organic layer150may further include a hole transport region located between the first electrode110and the emission layer, and an electron transport region located between the emission layer and the second electrode190.

[Hole Transport Region in Organic Layer150]

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

For example, the hole transport region 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, a hole injection layer/hole transport layer/emission auxiliary layer, a hole injection layer/emission auxiliary layer, a hole transport layer/emission auxiliary layer, or a hole injection layer/hole transport layer/electron blocking layer, wherein the constituting layers of each structure are sequentially stacked on the first electrode110in each stated order, but the structure of the hole transport region is not limited thereto.

In Formulae 201 and 202,

xa5 may be an integer from 1 to 10, and

For example, R201and R202in Formula 202 may optionally be linked to each other via a single bond, a dimethyl-methylene group, or a diphenyl-methylene group, and R203and R204may optionally be linked to each other via a single bond, a dimethyl-methylene group, or a diphenyl-methylene group.

In an embodiment, in Formulae 201 and 202,

L201to L205may each independently be selected from:

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

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

Q31to Q33may each independently be the same as described above.

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

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

In one or more embodiments, at least one of R201to R204in Formula 202 may be selected from:

a carbazolyl group; and

In an embodiment, the compound represented by Formula 201 may be represented by Formula 201-1:

In an embodiment, the compound represented by Formula 201 may be represented by Formula 201-2, but embodiments of the present disclosure are not limited thereto:

In one or more embodiments, the compound represented by Formula 201 may be represented by Formula 201-2(1), but embodiments of the present disclosure are not limited thereto:

In one or more embodiments, the compound represented by Formula 201 may be represented by Formula 201A(1), but embodiments of the present disclosure are not limited thereto:

In one or more embodiments, the compound represented by Formula 201 may be represented by Formula 201A-1, but embodiments of the present disclosure are not limited thereto:

In an embodiment, the compound represented by Formula 202 may be represented by Formula 202-1:

In one or more embodiments, the compound represented by Formula 202 may be represented by Formula 202-1(1):

In one or more embodiments, the compound represented by Formula 202 may be represented by Formula 202A:

In one or more embodiments, the compound represented by Formula 202 may be represented by Formula 202A-1:

L201to L203, xa1 to xa3, xa5, and R202to R204may each independently be the same as described above,

L205may be selected from a phenylene group and a fluorenylene group,

X211may be selected from O, S, and N(R211),

X212may be selected from O, S, and N(R212),

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

The hole transport region may include at least one compound selected from Compounds HT1 to HT48, but embodiments of the present disclosure are not limited thereto:

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

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

In an embodiment, a lowest unoccupied molecular orbital (LUMO) energy level of the p-dopant may be substantially equal to or less than −3.5 eV.

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

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

a metal oxide (such as tungsten oxide and/or molybdenum oxide);

a compound represented by Formula 221,

In Formula 221,

[Emission Layer in Organic Layer150]

The emission layer may include a host and a dopant. The dopant may include at least one selected from a phosphorescent dopant and a fluorescent dopant.

An amount of the dopant in the emission layer may be, based on about 100 parts by weight of the host, about 0.01 parts by weight to about 15 parts by weight, but embodiments of the present disclosure are not limited thereto.

The host may include a compound represented by Formula 301:

xb1 may be an integer from 0 to 5,

xb21 may be an integer from 1 to 5, and

In an embodiment, Ar301in Formula 301 may be selected from:

When xb11 in Formula 301 is 2 or more, two or more Ar301(s) may be linked to each other via a single bond.

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

In Formulae 301-1 and 301-2,

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

L301, xb1, R301, and Q31to Q33may each independently be the same as described above,

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

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

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

For example, L301to L304in Formulae 301, 301-1, and 301-2 may each independently be selected from:

Q31to Q33may each independently be the same as described above.

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

Q31to Q33may each independently be the same as described above.

In one or more 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) and an Mg complex. In some embodiments, the host may be a Zn complex.

[Phosphorescent Dopant Included in Emission Layer in Organic Layer150]

In Formulae 401 and 402,

L401may be a ligand represented by Formula 402, and xc1 may be 1, 2, or 3, wherein, when xc1 is 2 or more, two or more L401(s) may be identical to or different from each other,

L402may be an organic ligand, and xc2 may be an integer from 0 to 4, wherein, when xc2 is 2 or more, two or more L402(s) may be identical to or different from each other,

X401to X404may each independently be nitrogen or carbon,

X401and X403may be optionally linked via a single bond or a double bond, and X402and X404may be optionally linked via a single bond or a double bond,

A401and A402may each independently be a C5-C60carbocyclic group or a C1-C60heterocyclic group,

X406may be a single bond, O, or S,

R401and R402may 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-C20alkyl group, a substituted or unsubstituted C1-C20alkoxy 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, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q401)(Q402)(Q403), —N(Q401)(Q402), —B(Q401)(Q402), —C(═O)(Q401), —S(═O)2(Q401), and —P(═O)(Q401)(Q402), and Q401to Q403may each independently be selected from a C1-C10alkyl group, a C1-C10alkoxy group, a C6-C20aryl group, and a C1-C20heteroaryl group,

* and *′ in Formula 402 each indicate a binding site to a M in Formula 401.

In one or more embodiments, in Formula 402, i) X401may be nitrogen and X402may be carbon, or ii) X401and X402may each be nitrogen at the same time.

In one or more embodiments, R401and R402in Formula 402 may each independently be selected from:

a C1-C20alkyl group, and a C1-C20alkoxy 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 phenyl group, a naphthyl group, a cyclopentyl group, a cyclohexyl group, an adamantanyl group, a norbornanyl group, and a norbornenyl group;

Q401to Q403may each independently be selected from a C1-C10alkyl group, a C1-C10alkoxy group, a phenyl group, a biphenyl group, and a naphthyl group, but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, when xc1 in Formula 401 is 2 or more, two A401(s) in two or more L401(s) may optionally be linked to each other via X407(which is a linking group), and two A402(s) may optionally be linked to each other via X408(which is a linking group) (see Compounds PD1 to PD4 and PD7). X407and X408may each independently be a single bond, *—O—*′, *—S—*′, *—C(═O)—*′, *—N(Q413)-*′, *—C(Q413)(Q414)-*, or *—C(Q413)=C(Q414)-*′ (wherein Q413and Q414may each independently be hydrogen, deuterium, a C1-C20alkyl group, a C1-C20alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group), but embodiments of the present disclosure are not limited thereto.

L402in Formula 401 may be a monovalent, divalent, or trivalent organic ligand. For example, L402may be selected from halogen, diketone (for example, acetylacetonate), carboxylic acid (for example, picolinate), —C(═O), isonitrile, —CN, and a phosphorus-based ligand (for example, phosphine or phosphite), but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, the phosphorescent dopant may be selected from, for example, Compounds PD1 to PD25, but embodiments of the present disclosure are not limited thereto:

The fluorescent dopant may include an arylamine compound or a styrylamine compound.

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

In Formula 501,

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

xd4 may be an integer from 1 to 6.

In an embodiment, Ar501in Formula 501 may be selected from:

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

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

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

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

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

[Electron Transport Region in Organic Layer150]

The electron transport region may include at least one layer selected from a buffer layer, a hole blocking layer, an electron control layer, an electron transport layer, and an electron injection layer, but embodiments of the present disclosure are not limited thereto.

For example, the electron transport region may have an electron transport layer/electron injection layer structure, a hole blocking layer/electron transport layer/electron injection layer structure, an electron control layer/electron transport layer/electron injection layer structure, or a buffer layer/electron transport layer/electron injection layer structure, wherein the constituting layers of each structure are sequentially stacked on the emission layer in each stated order. However, embodiments of the structure of the electron transport region are not limited thereto.

The electron transport region (for example, a buffer layer, a hole blocking layer, an electron control layer, and/or an electron transport layer 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 electron transport region may include the heterocyclic compound represented by Formula 1.

xe1 may be an integer from 0 to 5,

xe21 may be an integer from 1 to 5.

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

In an embodiment, Ar601in Formula 601 may be selected from:

When xe11 in Formula 601 is 2 or more, two or more Ar601(s) may be linked to each other via a single bond.

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

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

In Formula 601-1,

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

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

xe611 to xe613 may each independently be the same as described in connection with xe1,

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

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

In one or more 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 Q602may each independently be the same as described above.

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

The thicknesses of the buffer layer, the hole blocking layer, and/or the electron control layer may be about 20 Å to about 1,000 Å, for example, about 30 Å to about 300 Å. When the thicknesses of the buffer layer, the hole blocking layer, and/or the electron control layer are within the range above, excellent hole blocking characteristics and/or excellent electron control characteristics may be obtained without a substantial increase in driving voltage.

A thickness of the electron transport layer may be 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 is within the range described above, satisfactory electron transport characteristics may be obtained without a substantial increase in driving voltage.

The metal-containing material may include at least one selected from an alkali metal complex and an 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 phenyloxadiazole, a hydroxy phenylthiadiazole, a hydroxy phenylpyridine, a hydroxy phenylbenzimidazole, a hydroxy phenylbenzothiazole, a bipyridine, a phenanthroline, and a cyclopentadiene, but embodiments of the present disclosure are not limited thereto.

The electron transport region may include an electron injection layer to facilitate the injection of electrons from the second electrode190. The electron injection layer may directly contact the second electrode190.

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 combination thereof.

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

The rare earth metal may be selected from scandium (Sc), yttrium (Y), cerium (Ce), terbium (Tb), ytterbium (Yb), and gadolinium (Gd).

The alkali metal compound, the alkaline earth-metal compound, and the rare earth metal compound may each independently 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, and/or K2O), and alkali metal halides (such as LiF, NaF, CsF, KF, LiI, NaI, CsI, and/or KI). In an embodiment, the alkali metal compound may be selected from LiF, Li2O, NaF, LiI, NaI, CsI, and KI, but embodiments of the present disclosure are not limited thereto.

The alkaline earth-metal compound may be selected from alkaline earth-metal oxides (such as BaO, SrO, CaO, BaxSr1-xO (0<x<1), and/or BaxCa1-xO (0<x<1)). In an embodiment, the alkaline earth-metal compound may be selected from BaO, SrO, and CaO, but embodiments of the present disclosure are not limited thereto.

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

The alkali metal complex, the alkaline earth-metal complex, and the rare earth metal complex may respectively include an alkali metal ion, alkaline earth-metal ion, and rare earth metal ion 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 phenyloxadiazole, hydroxy phenylthiadiazole, hydroxy phenylpyridine, hydroxy phenylbenzimidazole, hydroxy phenylbenzothiazole, bipyridine, phenanthroline, and cyclopentadiene, but embodiments of the present disclosure are not limited thereto.

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

The second electrode190is located on the organic layer150. The second electrode190may be a cathode which is an electron injection electrode, and in this regard, a material for forming the second electrode190may be selected from a metal, an alloy, an electrically conductive compound, and a combination thereof, each having a relatively low work function.

The second electrode190may 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 embodiments of the present disclosure are not limited thereto. The second electrode190may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode.

An organic light-emitting device20ofFIG. 2includes a first capping layer210, the first electrode110, the organic layer150, and the second electrode190, which are sequentially stacked in this stated order. An organic light-emitting device30ofFIG. 3includes the first electrode110, the organic layer150, the second electrode190, and a second capping layer220, which are sequentially stacked in this stated order. An organic light-emitting device40ofFIG. 4includes a first capping layer210, a first electrode110, an organic layer150, a second electrode190, and a second capping layer220, which are sequentially stacked in this stated order.

RegardingFIGS. 2 to 4, the first electrode110, the organic layer150, and the second electrode190may each be understood by referring to the descriptions presented in connection withFIG. 1.

In the organic layer150of each of the organic light-emitting devices20and40, light generated in the emission layer may pass through the first electrode110(which may be a semi-transmissive electrode or a transmissive electrode) and the first capping layer210toward the outside, and in the organic layer150of each of the organic light-emitting devices30and40, light generated in the emission layer may pass through the second electrode190(which may be a semi-transmissive electrode or a transmissive electrode) and the second capping layer220toward the outside.

The first capping layer210and the second capping layer220may increase the external luminescence efficiency of the device according to the principle of constructive interference.

The first capping layer210and the second capping layer220may each independently 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.

At least one selected from the first capping layer210and the second capping layer220may each independently include at least one material selected from carbocyclic compounds, heterocyclic compounds, amine-based compounds, porphyrin derivatives, phthalocyanine derivatives, naphthalocyanine derivatives, alkali metal complexes, and alkaline earth metal complexes. The carbocyclic compound, the heterocyclic compound, and the amine-based compound may each independently be optionally substituted with a substituent containing at least one element selected from O, N, S, Se, Si, F, Cl, Br, and I. In an embodiment, at least one of the first capping layer210and the second capping layer220may each independently include an amine-based compound.

In an embodiment, at least one selected from the first capping layer210and the second capping layer220may each independently include the compound represented by Formula 201 or the compound represented by Formula 202.

In one or more embodiments, at least one of the first capping layer210and the second capping layer220may each independently include a compound selected from Compounds HT28 to HT33 and Compounds CP1 to CP5, but embodiments of the present disclosure are not limited thereto:

Hereinbefore, the organic light-emitting device according to an embodiment has been described in connection withFIGS. 1 to 4. However, embodiments of the present disclosure are not limited thereto.

The layers constituting the hole transport region, the emission layer, and the layers constituting the electron transport region may be formed in a set or predetermined region 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.

[General Definition of Substituents]

The term “C1-C60alkoxy group” as used herein refers to a monovalent group represented by -OA101(wherein A101is a C1-C6alkyl group), and non-limiting examples thereof include a methoxy group, an ethoxy group, and an isopropyloxy group.

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

The term “monovalent non-aromatic condensed polycyclic group” as used herein refers to a monovalent group having two or more rings condensed with each other, only carbon atoms (for example, 8 to 60 carbon atoms) as ring-forming atoms, and no aromaticity in its entire molecular structure. Non-limiting examples of the monovalent non-aromatic condensed polycyclic group include an adamantyl group and a fluorenyl group. The term “divalent non-aromatic condensed polycyclic group” as used herein refers to a divalent group having substantially 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 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 (for example, 1 to 60 carbon atoms) as a ring-forming atom, and no aromaticity in its entire molecular structure. Non-limiting examples of the monovalent non-aromatic condensed heteropolycyclic group include a 9H-xanthenyl group and a carbazolyl group. The term “divalent non-aromatic condensed heteropolycyclic group” as used herein refers to a divalent group having substantially the same structure as the monovalent non-aromatic condensed heteropolycyclic group.

The term “C5-C60carbocyclic group” as used herein refers to a monocyclic or polycyclic group that includes only carbon as a ring-forming atom and consists of 5 to 60 carbon atoms. The C5-C60carbocyclic group may be an aromatic carbocyclic group or a non-aromatic carbocyclic group. The C5-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 embodiments, depending on the number of substituents connected to the C5-C60carbocyclic group, the C5-C60carbocyclic group may be a trivalent group or a quadrivalent group.

The term “C1-C60heterocyclic group” as used herein refers to a group having substantially the same structure as the C5-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 1 to 60).

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

Hereinafter, a compound according to embodiments and an organic light-emitting device according to embodiments will be described in more detail with reference to Synthesis Examples and Examples. The wording “B was used instead of A” used in describing Synthesis Examples indicates that an identical molar equivalent of B was used in place of A.

EXAMPLES

Synthesis Example 1: Synthesis of Compound 1

(1) Synthesis of Sub 1-1

4′-iodo-[1,1′-biphenyl]-4-carbonitrile (3.0 g, 10 mmol), (4-bromonaphthalen-1-yl)boronic acid (2.0 g, 8 mmol), Pd(PPh3)4(0.46 g, 0.4 mmol), K2CO3(4.2 g, 30 mmol), toluene, and water were mixed together, and the mixed solution was heated at a temperature of 120° C. for 12 hours, and then stirred under reflux. After completion of the reaction, distilled water was added to dilute the reaction solution at room temperature, and an extraction process was performed thereon using methylene chloride and water. An organic layer extracted therefrom was dried with anhydrous MgSO4, and then concentrated. The resulting compound was filtered through a silica gel column, and re-crystallized to obtain 1.6 g of Sub 1-1 (yield: 52%).

(2) Synthesis of Sub 1-2

Sub 1-1 (1.5 g, 4 mmol) was dissolved in THF, the temperature of the reaction product was lowered to −78° C., and n-BuLi (2.5 M in hexane) (0.4 g, 6 mmol) was slowly added dropwise thereto. Then, the reaction product was stirred for 30 minutes. Afterwards, the temperature of the reaction product was lowered to −78° C., and triisopropyl borate (1.5 g, 8 mmol) was added dropwise thereto. The resulting solution was stirred at room temperature, water was added to dilute the solution, and 2N HCl was added thereto. After completion of the reaction, an extraction process was performed thereon using ethyl acetate and water. An organic layer extracted therefrom was dried with anhydrous MgSO4, and then concentrated. The resulting compound was filtered through a silica gel column, and re-crystallized to obtain 0.9 g of Sub 1-2 (yield: 64%).

(3) Synthesis of Compound 1

Sub 1-2 (0.9 g, 2.57 mmol), 2-chloro-4-phenylquinazoline (0.8 g, 3.3 mmol), Pd(PPh3)4(0.46 g, 0.4 mmol), K2CO3(4.2 g, 30 mmol), toluene, and water were mixed together, and the mixed solution was heated at a temperature of 120° C. for 12 hours, and then stirred under reflux. After completion of the reaction, distilled water was added to dilute the reaction solution at room temperature, and an extraction process was performed thereon using methylene chloride and water. An organic layer extracted therefrom was dried with MgSO4, and then concentrated. A resulting compound was filtered through a silica gel column, and re-crystallized to obtain 0.6 g of Compound 1 (MS:[M+H]+=510, yield: 46%).

Synthesis Example 2: Synthesis of Compound 2

(1) Synthesis of Compound 2

0.6 g of Compound 2 (MS:[M+H]+=586, yield: 38%) was obtained in substantially the same manner as used to synthesize Compound 1, except that 4-([1,1′-biphenyl]-4-yl)-2-bromoquinazoline (1.2 g, 3.3 mmol) was used instead of 2-chloro-4-phenylquinazoline.

Synthesis Example 3: Synthesis of Compound 3

(1) Synthesis of Compound 3

0.7 g of Compound 3 (MS:[M+H]+=560, yield: 49%) was obtained in substantially the same manner as used to synthesize Compound 1, except that 2-bromo-4-(naphthalen-2-yl)quinazoline (1.1 g, 3.3 mmol) was used instead of 2-chloro-4-phenylquinazoline.

Synthesis Example 4: Synthesis of Compound 7

(1) Synthesis of Compound 7

0.7 g of Compound 7 (MS:[M+H]+=515, yield: 51%) was obtained in substantially the same manner as used to synthesize Compound 1, except that 2-bromo-4-(phenyl-d5)quinazoline (1.0 g, 3.3 mmol) was used instead of 2-chloro-4-phenylquinazoline.

Synthesis Example 5: Synthesis of Compound 10

(1) Synthesis of Sub 10-1

2-chloro-4-phenylquinazoline (1.9 g, 8 mmol), 1,4-phenylenediboronic acid (1.6 g, 10 mmol), Pd(PPh3)4(0.46 g, 0.4 mmol), K2CO3(4.2 g, 30 mmol), toluene, and water were mixed together, and the mixed solution was heated at a temperature of 120° C. for 12 hours, and then stirred under reflux. After completion of the reaction, distilled water was added to dilute the reaction solution at room temperature, and an extraction process was performed thereon using methylene chloride and water. An organic layer extracted therefrom was dried with anhydrous MgSO4, and then concentrated. The resulting compound was filtered through a silica gel column, and re-crystallized to obtain 1.6 g of Sub 10-1 (yield: 60%).

(2) Synthesis of Compound 10

Synthesis Example 6: Synthesis of Compound 12

(1) Synthesis of Sub 12-1

1.4 g of Sub 12-1 (yield: 45%) was obtained in substantially the same manner as used to synthesize Sub 10-1, except that 2-bromo-4-(naphthalen-2-yl)quinazoline (2.7 g, 8 mmol) was used instead of 2-chloro-4-phenylquinazoline.

(2) Synthesis of Compound 12

0.73 g of Compound 12 (MS:[M+H]+=536, yield: 32%) was obtained in substantially the same manner as used to synthesize Compound 10, except that Sub 12-1 (1.4 g, 3.6 mmol) was used instead of Sub 10-1.

Synthesis Example 7: Synthesis of Compound 31

(1) Synthesis of Sub 31-1

(2) Synthesis of Compound 31

Sub 31-1 (1.9 g, 4.1 mmol), phenylboronic acid (0.6 g, 5 mmol), Pd(PPh3)4(0.46 g, 0.4 mmol), K2CO3(4.2 g, 30 mmol), toluene, and water were mixed together, and the mixed solution was heated at a temperature of 120° C. for 12 hours, and then stirred under reflux. After completion of the reaction, distilled water was added to dilute the reaction solution at room temperature, and an extraction process was performed thereon using methylene chloride and water. An organic layer extracted therefrom was dried with anhydrous MgSO4, and then concentrated. A resulting compound was filtered through a silica gel column, and re-crystallized to obtain 0.8 g of Compound 31 (MS:[M+H]+=510, yield: 39%).

Synthesis Example 8: Synthesis of Compound 34

(1) Synthesis of Compound 34

0.62 g of Compound 34 (MS:[M+H]+=560, yield: 27%) was obtained in substantially the same manner as used to synthesize Compound 31, except that naphthalen-1-ylboronic acid (0.86 g, 5 mmol) was used instead of phenylboronic acid.

Synthesis Example 9: Synthesis of Compound 35

(1) Synthesis of Compound 35

0.73 g of Compound 35 (MS:[M+H]+=636, yield: 28%) was obtained in substantially the same manner as used to synthesize Compound 31, except that 4-(naphthalen-1-yl)phenyl)boronic acid (1.24 g, 5 mmol) was used instead of phenylboronic acid.

Synthesis Example 10: Synthesis of Compound 55

(1) Synthesis of Compound 55

0.4 g of Compound 55 (MS:[M+H]+=510, yield: 19%) was obtained in substantially the same manner as used to synthesize Compound 1, except that 2-bromo-3-phenylquinoxaline (1.43 g, 5 mmol) was used instead of 2-chloro-4-phenylquinazoline.

Synthesis methods of compounds other than Compounds of Synthesis Examples may be easily recognized by those of ordinary skill in the art by referring to the synthesis mechanisms and source materials described above.

As an anode, a Corning 15 Ω/cm2(1,200 Å) ITO glass substrate was cut to a size of 50 mm×50 mm×0.75 mm, sonicated with isopropyl alcohol and pure water each for 5 minutes, and then cleaned by exposure to ultraviolet rays and ozone for 15 minutes. The ITO glass substrate was provided to a vacuum deposition apparatus.

A material HT1 was vacuum-deposited on the ITO glass substrate to form a first hole transport layer having a thickness of 1,200 Å, and a hole transport compound HT2 was vacuum-deposited on the first hole transport layer to form a second hole transport layer having a thickness of 100 Å.

BH and BD were co-deposited on the second hole transport layer at a weight ratio of 97:3 to form an emission layer having a thickness of 200 Å.

Then, Compound 1 was deposited on the emission layer to form a first electron transport layer having a thickness of 300 Å, an alkali metal halide LiQ was deposited on the first electron transport layer to form an electron injection layer having a thickness of 10 Å, and Mg/Ag was vacuum-deposited on the electron injection layer to a thickness of 100 Å to form an electrode, thereby completing the manufacture of an organic light-emitting device.

Examples 2 to 13 and Comparative Examples 1 to 5

Additional organic light-emitting devices were manufactured in substantially the same manner as in Example 1, except that the Compounds shown in Table 1 were each used instead of Compound 1 in forming a first electron transport layer.

Evaluation Example C

For each the organic light-emitting devices of Examples 1 to 13 and Comparative Examples 1 to 5, device efficiency and life span LT90(e.g., the time until the initial luminance was decreased by 90%) were measured at a driving current density of 10 mA/cm2, and the results are shown in Table 1.Luminance: Power was supplied from a current-voltmeter (Keithley SMU 236) and measured using a luminance meter PR650.Efficiency: Power was supplied from a current-voltmeter (Keithley SMU 236) and measured using a luminance meter PR650.

From Table 1, it was confirmed that, in a case in which the Compounds of the present disclosure were used as the material for forming the electron transport layer, the organic light-emitting devices had high luminescence efficiency and long lifespan characteristics, compared with a case in which the Compounds of Comparative Examples 1 to 5 were used.

According to the one or more embodiments, a heterocyclic compound represented by Formula 1 has excellent electron transport capability, and an organic light-emitting device including the heterocyclic compound represented by Formula 1 may accordingly have low driving voltage, high efficiency, high luminance, and/or long lifespan characteristics.