Organometallic compound, organic light-emitting device including the same, and diagnostic composition including the organometallic compound

Provided are an organometallic compound, an organic light-emitting device including the organometallic compound, and a diagnostic composition including the organometallic compound.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of Korean Patent Application No. 10-2019-0156110, filed on Nov. 28, 2019, in the Korean Intellectual Property Office, the content of which is incorporated herein in its entirety by reference.

BACKGROUND

One or more embodiments relate to organometallic compounds, organic light-emitting devices including the same, and diagnostic compositions including the same.

2. Description of Related Art

Organic light-emitting devices are self-emission devices, which have improved characteristics in terms of viewing angles, response time, brightness, driving voltage, and response speed, and produce full-color images.

Meanwhile, luminescent compounds, for example, phosphorescent compounds, may be used for monitoring, sensing, and detecting biological materials such as various cells and proteins.

SUMMARY

One or more embodiments relate to organometallic compounds, organic light-emitting devices including the same, and diagnostic compositions including the same.

According to an aspect, provided is an organometallic compound represented by Formula 1.
M(L1)n1(L2)n2Formula 1

In Formula 1,

M may be a transition metal,

L1may be a ligand represented by Formula 2-1,

n1 may be 1, 2, or 3, when n1 is 2 or more, two or more L1(s) may be identical to or different from each other,

L2may be a ligand represented by Formula 2-2,

n2 may be 1, 2, 3, or 4, when n2 is two or more, two or more L2(s) may be identical to or different from each other,

in Formulae 2-1 and 2-2,

CY1to CY3may each independently be a C5-C30carbocyclic group, a C1-C30heterocyclic group, or any combination thereof,

R6may be a Si-containing group or a Ge-containing group,

a1 to a3 may each independently be an integer from 0 to 10, wherein, when a1 is an integer of 2 or more, two or more R1(s) may be identical to or different from each other, when a2 is an integer of 2 or more, two or more R2(s) may be identical to or different from each other, and when a3 is an integer of 2 or more, two or more R3(s) may be identical to or different from each other,

a4 may be an integer from 0 to 4, and when a4 is an integer of 2 or more, two or more R4(s) may be identical to or different from each other,

a6 may be an integer from 1 to 4, and when a6 is an integer of 2 or more, two or more R6(s) may be identical to or different from each other,

two or more neighboring R1(s) are optionally linked to each other to form a C5-C30carbocyclic group that is unsubstituted or substituted with at least one R10aor a C1-C30heterocyclic group that is unsubstituted or substituted with at least one R10a,

two or more neighboring R2(s) are optionally linked to each other to form a C5-C30carbocyclic group that is unsubstituted or substituted with at least one R10aor a C1-C30heterocyclic group that is unsubstituted or substituted with at least one R10a,

two or more neighboring R3(s) are optionally linked to each other to form a C5-C30carbocyclic group that is unsubstituted or substituted with at least one R10aor a C1-C30heterocyclic group that is unsubstituted or substituted with at least one R10a,

two or more neighboring R4(s) are optionally linked to each other to form a C5-C30carbocyclic group that is unsubstituted or substituted with at least one R10aor a C1-C30heterocyclic group that is unsubstituted or substituted with at least one R10a,

two or more of R1to R5are optionally linked to each other to form a C5-C30carbocyclic group that is unsubstituted or substituted with at least one R10aor a C1-C30heterocyclic group that is unsubstituted or substituted with at least one R10a,

R10ais the same as described in connection with R1,

* and *′ each indicate a binding site to M in Formula 1, and

Another aspect provides an organic light-emitting device including a first electrode, a second electrode, and an organic layer between the first electrode and the second electrode and including an emission layer, wherein the organic layer includes at least one of the organometallic compound.

The organometallic compound in the organic layer may function as a dopant.

DETAILED DESCRIPTION

“Or” means “and/or.” As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.

An aspect of the present disclosure provides an organometallic compound represented by Formula 1:
M(L1)n1(L2)n2.  Formula 1

In Formula 1, M may be a transition metal.

For example, M may be a Period 1 transition metal, a Period 2 transition metal, or a Period 3 transition metal.

In one or more embodiments, M may be Ir, Pt, Os, or Rh, but embodiments are not limited thereto.

L1in Formula 1 may be a ligand represented by Formula 2-1:

The description of Formula 2-1 is the same as described in the specification.

n1 in Formula 1 indicates the number of L1, and may be 1, 2, or 3, and when n1 is 2 or more, two or more L1(s) may be identical to or different from each other.

L2in Formula 1 may be a ligand represented by Formula 2-2:

The description of Formula 2-2 is the same as described in the specification.

n2 in Formula 1 indicates the number of L2, and may be 1, 2, 3, or 4, and when n2 is 2 or more, two or more L2(s) may be identical to or different from each other.

In one or more embodiments, M in Formula 1 may be Ir or Os, and the sum of n1 and n2 may be 3 or 4. For example, regarding Formula 1, M may be Ir or Os, n1 may be 2, and n2 may be 1.

CY1to CY3in Formulae 2-1 and 2-2 may each independently be a C5-C30carbocyclic group, a C1-C30heterocyclic group, or any combination thereof.

In one or more embodiments, ring CY1to ring CY3may each independently be:

In one or more embodiments, R1to R4may each independently be:

wherein Q1to Q9may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid or a salt thereof, a sulfonic acid or a salt thereof, a phosphoric acid or a salt thereof, 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 C2-C10heterocycloalkenyl group, a C6-C60aryl group, a C6-C60aryl group substituted with at least one a C1-C60alkyl group, a C6-C60aryl group, or any combination thereof, 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, or any combination thereof, but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, R5may be:

a C1-C20alkyl group unsubstituted or substituted with at least one deuterium; and

R6in Formula 2-1 may be a Si-containing group or a Ge-containing group.

The term “a Si-containing group” used herein refers to a monovalent substituent group having a Si atom, for example, a group in which at least one hydrogen (H) of —SiH3is substituted with deuterium, a methyl group, an ethyl group, a phenyl group, or the like. Examples of the Si-containing group are —Si(CH3)3, —Si(CH3)2(CH2CH3), —Si(Ph)3, and —Si(CH3)2(Ph).

The term “a Ge-containing group” used herein refers to a monovalent substituent group having a Ge atom, for example, a group in which at least one hydrogen (H) of —GeH3is substituted with deuterium, a methyl group, an ethyl group, a phenyl group, or the like. Examples of the Ge-containing group are —Ge(CH3)3, —Ge(CH3)2(CH2CH3), —Ge(Ph)3, and —Ge(CH3)2(Ph).

In one or more embodiments, R6in Formula 1 may be represented by Formula 3-1:

In Formula 3-1,

A may be Si or Ge,

*″ is a binding site to an adjacent group.

R61to R63may be identical to or different from each other.

For example, R61to R63may be identical to each other. For example, R61and R62may be different from each other. For example, R61and R62may be different from each other, and R61and R63may be different from each other. For example, R61to R63may be different from each other.

In one or more embodiments, Formula 2-1 may be represented by one of Formulae 4-1 to 4-4.

In Formulae 4-1 to 4-4,

A may be Si or Ge, and

R61to R63, CY1, R1, R3, a1, and a3 may be the same as described above.

In one or more embodiments, Formula 2-1 may be represented by one of Formulae 4-1-1 to 4-4-1.

In Formulae 4-1-1 to 4-4-1,

A, R61to R63, CY1, R1, and a1 may be the same as described above,

R3a, R3b, R3c, and R3dmay each be the same as described in connection with R3, wherein R3cis not a phenyl group.

In one or more embodiments, Formula 2-2 may be represented by Formula 5-1:

In Formula 5-1,

R11to R14are the same as described in connection with R3, and

CY2, R2, R5, and a2 are the same as described above.

In one or more embodiments, X11may be C(R11), X12may be C(R12), X13may be C(R13), and X14may be C(R14).

In one or more embodiments, X11may be N, X12may be C(R12), X13may be C(R13), and X14may be C(R14). In one or more embodiments, may be C(R11), X12may be N, X13may be C(R13), and X14may be C(R14). In one or more embodiments, X11may be C(R11), X12may be C(R12), X13may be N, and X14may be C(R14). In one or more embodiments, X11may be C(R11), X12may be C(R12), X13may be C(R13), and X14may be N. In one or more embodiments, X11may be N, X12may be N, X13may be C(R13), and X14may be C(R14). In one or more embodiments, X11may be N, X12may be C(R12), X13may be N, and X14may be C(R14). In one or more embodiments, X11may be N, X12may be C(R12), X13may be C(R13), and X14may be N. In one or more embodiments, may be C(R11), X12may be N, X13may be N, and X14may be C(R14). In one or more embodiments, may be C(R11), X12may be N, X13may be C(R13), and X14may be N. In one or more embodiments, may be C(R11), X12may be C(R12), X13may be N, and X14may be N. In one or more embodiments, X11may be N, X12may be N, X13may be N, and X14may be C(R14). In one or more embodiments, X11may be N, X12may be N, X13may be C(R13), and X14may be N. In one or more embodiments, X11may be N, X12may be C(R12), X13may be N, and X14may be N. In one or more embodiments, X11may be C(R11), X12may be N, X13may be N, and X14may be N. In one or more embodiments, X11may be N, X12may be N, X13may be N, and X14may be N.

Regarding Formulae 2-1 and 2-2, a1 to a3 may each independently be an integer from 0 to 10, wherein, when a1 is 2 or more, two or more R1(s) may be identical to or different from each other, when a2 is 2 or more, two or more R2(s) may be identical to or different from each other, and when a3 is 2 or more, two or more R3(s) may be identical to or different from each other, and a4 may each independently be an integer from 0 to 4, wherein, when a4 is 2 or more, two or more R4(s) may be identical to or different from each other, and a6 may be an integer from 1 to 4, wherein, when a6 is 2 or more, R6(s) may be identical to or different from each other.

Regarding Formulae 2-1 and 2-2, (i) two or more neighboring R1(s) may optionally be linked together to form a C5-C30carbocyclic group that is unsubstituted or substituted with at least one R10aor a C1-C30heterocyclic group that is unsubstituted or substituted with at least one R10a, (ii) two or more neighboring R2(s) may optionally be linked together to form a C5-C30carbocyclic group that is unsubstituted or substituted with at least one R10aor a C1-C30heterocyclic group that is unsubstituted or substituted with at least one R10a, (iii) two or more neighboring R3(s) may optionally be linked together to form a C5-C30carbocyclic group that is unsubstituted or substituted with at least one R10aor a C1-C30heterocyclic group that is unsubstituted or substituted with at least one R10a, (iv) two or more neighboring R4(s) may optionally be linked together to form a C5-C30carbocyclic group that is unsubstituted or substituted with at least one R10aor a C1-C30heterocyclic group that is unsubstituted or substituted with at least one R10a, and (v) R1to R5may optionally be linked together to form a C5-C30carbocyclic group that is unsubstituted or substituted with at least one R10aor a C1-C30heterocyclic group that is unsubstituted or substituted with at least one R10a.

R10ais the same as described in connection with R1.

In one or more embodiments, the organometallic compound may be at least one of Compounds 1 to 9796 represented by (L1)2IrL2and may include ligand L1and ligand L2shown in Table 1 below and, but embodiments of the present disclosure are not limited thereto:

In the organometallic compound represented by Formula 1, L1may be a ligand represented by Formula 2-1, and L2may include a ligand represented by Formula 2-2. The organometallic compound is a heteroleptic organometallic compound.

By introducing at least one of a Si-containing group or a Ge-containing group to a pyridine ring in Formula 2-1, the energy level may be easily controlled, and by including a condensed ring as an upper ligand in Formula 2-2, the external luminescence efficiency may be substantially improved.

By introducing at least one of a Si-containing group or a Ge-containing group into a pyridine ring in Formula 2-1, the molecular orientation and electron mobility of the organometallic compound represented by Formula 1 are greatly improved as compared to a pyridine ring that is not substituted with a Si-containing group or a Ge-containing group, and thus, the external quantum efficiency of an electron device including the organometallic compound, for example, an organic light-emitting device including the organometallic compound may be improved.

By including a condensed ring as an upper ligand in Formula 2-2, compared to a ligand including a non-condensed ring, electrons are delocalized, providing electric stability and a rigid skeleton structure. Accordingly, the lifespan of an electron device including the organometallic compound, for example, an organic light-emitting device including the organometallic compound may be prolonged.

The highest occupied molecular orbital (HOMO) energy level, lowest unoccupied molecular orbital (LUMO) energy level, bandgap, S1energy level, and T1energy level of several compounds among organometallic compounds represented by Formula 1 were evaluated by using Gaussian 09 program with molecular structure optimization by density functional theory (DFT) based on B3LYP. Results thereof are shown in Table 2.

From Table 2, it is confirmed that the organometallic compound represented by Formula 1 has such electric characteristics that are suitable for use as a dopant for an electric device, for example, an organic light-emitting device.

Synthesis methods of the organometallic compound represented by Formula 1 may be recognizable by one of ordinary skill in the art by referring to Synthesis Examples provided below.

The organometallic compound represented by Formula 1 is suitable for use in an organic layer of an organic light-emitting device, for example, for use as a dopant in an emission layer of the organic layer. Thus, another aspect provides an organic light-emitting device that includes: a first electrode; a second electrode; and an organic layer between the first electrode and the second electrode and including an emission layer and at least one of the organometallic compound represented by Formula 1.

The organic light-emitting device may have, due to the inclusion of an organic layer including the organometallic compound represented by Formula 1, a low driving voltage, high efficiency, high power, high quantum efficiency, a long lifespan, a low roll-off ratio, and excellent color purity.

The organometallic compound of Formula 1 may be used between a pair of electrodes of an organic light-emitting device. For example, the organometallic compound represented by Formula 1 may be included in the emission layer. In this regard, the organometallic compound may act as a dopant, and the emission layer may further include a host (that is, an amount of the organometallic compound represented by Formula 1 is smaller than an amount of the host). The emission layer may emit green light, for example, green light having a maximum emission wavelength of 470 nm or more (for example, equal to or greater than about 470 nm and less than or equal to about 550 nm).

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

For example, the organic layer may include, as the organometallic compound, only Compound 1. In this regard, Compound 1 may exist only in the emission layer of the organic light-emitting device. In one or more embodiments, the organic layer may include, as the organometallic compound, Compound 1 and Compound 2. In this regard, Compound 1 and Compound 2 may exist in an identical layer (for example, both Compound 1 and Compound 2 may exist in an emission layer).

The first electrode may be an anode, which is a hole injection electrode, and the second electrode may be a cathode, which is an electron injection electrode; or the first electrode may be a cathode, which is an electron injection electrode, and the second electrode may be an anode, which is a hole injection electrode.

In one or more embodiments, in the organic light-emitting device, the first electrode is an anode, and the second electrode is a cathode, and the organic layer may further include a hole transport region between the first electrode and the emission layer and an electron transport region between the emission layer and the second electrode, and the hole transport region may include a hole injection layer, a hole transport layer, an electron blocking layer, a buffer layer, or any combination thereof, and the electron transport region may include a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

The term “organic layer” used herein refers to a single layer and/or a plurality of layers between the first electrode and the second electrode of the organic light-emitting device. The “organic layer” may include, in addition to an organic compound, an organometallic complex including metal.

FIGURE is a schematic cross-sectional view of an organic light-emitting device10according to an embodiment. Hereinafter, the structure of an organic light-emitting device according to an embodiment and a method of manufacturing an organic light-emitting device according to an embodiment will be described in connection with FIGURE. The organic light-emitting device10includes a first electrode11, an organic layer15, and a second electrode19, which are sequentially stacked.

A substrate may be additionally located under the first electrode11or above the second electrode19. For use as the substrate, any substrate that is used in organic light-emitting devices available in the art may be used, and the substrate may be a glass substrate or a transparent plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and water resistance.

In one or more embodiments, the first electrode11may be formed by depositing or sputtering a material for forming the first electrode11on the substrate. The first electrode11may be an anode. The material for forming the first electrode11may be materials with a high work function to facilitate hole injection. The first electrode11may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. The material for forming the first electrode11may be indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO2), or zinc oxide (ZnO). In one or more embodiments, the material for forming the first electrode11may be metal, such as magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), or magnesium-silver (Mg—Ag).

The first electrode11may have a single-layered structure or a multi-layered structure including two or more layers. For example, the first electrode11may have a three-layered structure of ITO/Ag/ITO, but the structure of the first electrode11is not limited thereto.

The organic layer15is located on the first electrode11.

The hole transport region may be located between the first electrode11and the emission layer.

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

The hole transport region may include only either a hole injection layer or a hole transport layer. In one or more embodiments, the hole transport region may have a hole injection layer/hole transport layer structure or a hole injection layer/hole transport layer/electron blocking layer structure, which are sequentially stacked in this stated order from the first electrode11.

When the hole transport region includes a hole injection layer, the hole injection layer may be formed on the first electrode11by using one or more suitable methods, for example, vacuum deposition, spin coating, casting, and/or Langmuir-Blodgett (LB) deposition.

When a hole injection layer is formed by vacuum deposition, the deposition conditions may vary according to a material that is used to form the hole injection layer, and the structure and thermal characteristics of the hole injection layer. For example, the deposition conditions may include a deposition temperature of about 100 to about 500° C., a vacuum pressure of about 10−8torr to about 10−3torr, and a deposition rate of about 0.01 Å/sec to about 100 Å/sec. However, the deposition conditions are not limited thereto.

When the hole injection layer is formed using spin coating, coating conditions may vary according to the material used to form the hole injection layer, and the structure and thermal properties of the hole injection layer. For example, a coating speed may be from about 2,000 rpm to about 5,000 rpm, and a temperature at which a heat treatment is performed to remove a solvent after coating may be from about 80° C. to about 200° C. However, the coating conditions are not limited thereto.

Conditions for forming a hole transport layer and an electron blocking layer may be understood by referring to conditions for forming the hole injection layer.

xa and xb in Formula 201 may each independently be an integer from 0 to 5, or 0, 1, or 2. For example, xa may be 1 and xb may be 0, but xa and xb are not limited thereto.

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid or a salt thereof, a sulfonic acid or a salt thereof, a phosphoric acid or a salt thereof, a C1-C10alkyl group (for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and so on), or a C1-C10alkoxy group (for example, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, and so on);

a phenyl group, a naphthyl group, an anthracenyl group, a fluorenyl group, a pyrenyl group or any combination thereof; or

a phenyl group, a naphthyl group, an anthracenyl group, or a pyridinyl group; or

According to an embodiment, the compound represented by Formula 201 may be represented by Formula 201A below, but embodiments of the present disclosure are not limited thereto:

R101, R111, R112, and R109in Formula 201A may be understood by referring to the description provided herein.

For example, the compound represented by Formula 201 and the compound represented by Formula 202 may include compounds HT1 to HT20 illustrated below, but are not limited thereto:

The hole transport region may further include a buffer layer.

Also, the buffer layer may compensate for an optical resonance distance according to a wavelength of light emitted from the emission layer, and thus, efficiency of a formed organic light-emitting device may be improved.

Then, an emission layer may be formed on the hole transport region by vacuum deposition, spin coating, casting, LB deposition, or the like. When the emission layer is formed by vacuum deposition or spin coating, the deposition or coating conditions may be similar to those applied in forming the hole injection layer although the deposition or coating conditions may vary according to a material that is used to form the hole transport layer.

Meanwhile, when the hole transport region includes an electron blocking layer, a material for the electron blocking layer may be materials for the hole transport region described above and materials for a host to be explained later. However, the material for the electron blocking layer is not limited thereto. For example, when the hole transport region includes an electron blocking layer, a material for the electron blocking layer may be mCP, which will be explained later.

The emission layer may include a host and a dopant, and the dopant may include the organometallic compound represented by Formula 1.

The host may include at least one TPBi, TBADN, ADN (also referred to as “DNA”), CBP, CDBP, TCP, mCP, and Compound H50 to Compound H52:

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

a phenylene group, a naphthylene group, a phenanthrenylene group, a pyrenylene group, or any combination thereof; or

a phenylene group, a naphthylene group, a phenanthrenylene group, a pyrenylene group, or any combination thereof, each substituted with at least one of a phenyl group, a naphthyl group, an anthracenyl group, or any combination thereof.

a C1-C10alkyl group, a phenyl group, a naphthyl group, a phenanthrenyl group, a pyrenyl group, or any combination thereof; or

a phenyl group, a naphthyl group, a phenanthrenyl group, a pyrenyl group, or any combination thereof, each substituted with at least one a phenyl group, a naphthyl group, an anthracenyl group, or any combination thereof.

g, h, i, and j in Formula 301 may each independently be an integer from 0 to 4 and may be, for example, 0, 1, or 2.

a C1-C10alkyl group, substituted with at least one a phenyl group, a naphthyl group, an anthracenyl group, or any combination thereof;

a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl, a phenanthrenyl group, a fluorenyl group, or any combination thereof;

a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenyl group, or any combination thereof, each substituted with at least one deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid or a salt thereof, a sulfonic acid or a salt thereof, a phosphoric acid or a salt thereof, a C1-C60alkyl group, a C2-C60alkenyl group, a C2-C60alkynyl group, a C1-C60alkoxy group, a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenyl group, or any combination thereof; or

In one or more embodiments, the host may include a compound represented by Formula 302 below:

Ar122to Ar125in Formula 302 are the same as described in detail in connection with Ar113in Formula 301.

Ar126and Ar127in Formula 302 may each independently be a C1-C10alkyl group (for example, a methyl group, an ethyl group, or a propyl group).

k and l in Formula 302 may each independently be an integer from 0 to 4. For example, k and l may be 0, 1, or 2.

When the organic light-emitting device is a full-color organic light-emitting device, the emission layer may be patterned into a red emission layer, a green emission layer, and a blue emission layer. In one or more embodiments, due to a stacked structure including a red emission layer, a green emission layer, and/or a blue emission layer, the emission layer may emit white light.

When the emission layer includes a host and a dopant, an amount of the dopant 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 embodiments of the present disclosure are not limited thereto.

Then, an electron transport region may be located on the emission layer.

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

For example, the electron transport region may have a hole blocking layer/electron transport layer/electron injection layer structure or an electron transport layer/electron injection layer structure, and the structure of the electron transport region is not limited thereto. The electron transport layer may have a single-layered structure or a multi-layered structure including two or more different materials.

Conditions for forming the hole blocking layer, the electron transport layer, and the electron injection layer which constitute the electron transport region may be understood by referring to the conditions for forming the hole injection layer.

When the electron transport region includes a hole blocking layer, the hole blocking layer may include, for example, at least one of BCP, Bphen, Balq, or any combination thereof, but embodiments of the present disclosure are not limited thereto.

A thickness of the hole blocking layer may 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 hole blocking layer is within these ranges, the hole blocking layer may have excellent hole blocking characteristics without a substantial increase in driving voltage.

The electron transport layer may further include at least one BCP, Bphen, Alq3, Balq, TAZ, NTAZ, or any combination thereof.

In one or more embodiments, the electron transport layer may include at least one of Compounds ET1 to ET25, but are not limited thereto:

The electron transport region may include an electron injection layer that promotes flow of electrons from the second electrode19thereinto.

The electron injection layer may include at least one LiF, NaCl, CsF, Li2O, BaO, or any combination thereof.

The second electrode19is located on the organic layer15. The second electrode19may be a cathode. A material for forming the second electrode19may be a metal, an alloy, an electrically conductive compound, which has a relatively low work function. For example, lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), or magnesium-silver (Mg—Ag) may be formed as the material for forming the second electrode19. To manufacture a top-emission type light-emitting device, a transmissive electrode formed using ITO or IZO may be used as the second electrode19.

Hereinbefore, the organic light-emitting device has been described with reference to FIGURE, but embodiments of the present disclosure are not limited thereto.

Another aspect provides a diagnostic composition including at least one of an organometallic compound represented by Formula 1.

The organometallic compound represented by Formula 1 provides high luminescent efficiency. Accordingly, a diagnostic composition including the organometallic compound may have high diagnostic efficiency.

The diagnostic composition may be used in various applications including a diagnosis kit, a diagnosis reagent, a biosensor, and a biomarker.

The term “C2-C10heterocycloalkenyl group” as used herein refers to a monovalent monocyclic group that has at least one N, O, P, Si, B, Se, Ge, Te, S, or any combination thereof as a ring-forming atom, 2 to 10 carbon atoms, and at least one double bond in its ring. Examples of the C2-C10heterocycloalkenyl group are a 2,3-dihydrofuranyl group and a 2,3-dihydrothiophenyl group. The term “C2-C10heterocycloalkenylene group” as used herein refers to a divalent group having the same structure as the C2-C10heterocycloalkenyl 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, a heteroatom N, O, P, Si, and S, other than carbon atoms, as a ring-forming atom, and no aromaticity in its entire molecular structure. The monovalent non-aromatic condensed heteropolycyclic group includes 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 “C5-C30carbocyclic group” as used herein refers to a saturated or unsaturated cyclic group having, as a ring-forming atom, 5 to 30 carbon atoms only. The C5-C30carbocyclic group may be a monocyclic group or a polycyclic group.

The term “C1-C30heterocyclic group” as used herein refers to a saturated or unsaturated cyclic group having, as a ring-forming atom, at least one N, O, P, Si, B, Se, Ge, Te, S, or any combination thereof other than 1 to 30 carbon atoms. The C1-C30heterocyclic group may be a monocyclic group or a polycyclic group.

Hereinafter, a compound and an organic light-emitting device according to embodiments are described in detail with reference to Synthesis Example and Examples. However, the organic light-emitting device is not limited thereto. The wording “B was used instead of A” used in describing Synthesis Examples means that an amount of A used was identical to an amount of B used, in terms of a molar equivalent.

EXAMPLES

Synthesis Example 1: Synthesis of Compound 1

Synthesis of Compound 1A

2-phenyl-5-(trimethylsilyl)pyridine (7.5 g, 33.1 mmol) and iridium chloride (5.2 g, 14.7 mmol) were mixed with 120 mL of ethoxyethanol and 40 mL of distilled water, and then the mixture was stirred while refluxing for 24 hours and cooled to room temperature. A solid material formed therefrom was separated by filtration and washed thoroughly with water/methanol/hexane in the stated order to obtain a solid which was then dried in a vacuum oven to obtain 8.2 g(yield of 82%) of Compound A1.

Synthesis of Compound 1B

Compound 1A (1.6 g, 1.2 mmol) was mixed with 45 mL of methylene chloride, and then AgOTf (0.6 g, 2.3 mmol) were mixed with 15 mL of methanol and added thereto. Subsequently, the mixture was stirred for 18 hours at room temperature while blocking light with aluminum foil, and then a solid (Compound 1B) obtained by removing a solid formed by celite filtration and concentrating a filtrate was used in the next reaction without additional purification.

Synthesis of Compound 1

Compound 1B (2.0 g, 2.3 mmol) and 1-methyl-2-phenyl-1H-benzo[d]imidazole (0.6 g, 2.8 mmol) were mixed with 100 mL of 2-ethoxyethanol, and then the mixture was stirred while refluxing for 24 hours and cooled to room temperature. A compound obtained therefrom was concentrated to obtain a solid which was then subject to column chromatography (eluent: methylene chloride (MC) and hexane) to obtain 0.9 g (yield of 46%) of Compound 1. The substance was identified by Mass and HPLC analysis.

Synthesis of Compound 15

Compound 15 (yield of 37%) was obtained by using the same method as the synthesis method of Compound 1 of Synthesis Example 1, except that 1-(3,5-diisopropyl-[1,1′-biphenyl]-4-yl)-2-phenyl-1H-benzo[d]imidazole was used instead of 1-methyl-2-phenyl-1H-benzo[d]imidazole. The substance was identified by Mass and HPLC analysis.

Synthesis of Compound 1886A

Compound 1886A (yield of 87%) was obtained by using the same method as the synthesis method of Compound 1A of Synthesis Example 1, except that 4-isobutyl-2-phenyl-5-(trimethylsilyl)pyridine was used instead of 2-phenyl-5-(trimethylsilyl)pyridine.

Synthesis of Compound 1886B

Compound 1886B was obtained by using the same method as the synthesis method of Compound 1B of Synthesis Example 1, except that Compound 1886A was used instead of Compound 1A. Obtained Compound 1886B was used in the next reaction without additional purification.

Synthesis of Compound 1886

Compound 1886 (yield of 36%) was obtained by using the same method as the synthesis method of Compound 1 of Synthesis Example 1, except that Compound 1886B was used instead of Compound 1B. The substance was identified by Mass and HPLC analysis.

Synthesis of Compound 1895

Compound 1895 (yield of 33%) was obtained by using the same method as the synthesis method of Compound 1886 of Synthesis Example 3, except that 1,2-diphenyl-1H-benzo[d]imidazole was used instead of 1-methyl-2-phenyl-1H-benzo[d]an imidazole. The substance was identified by Mass and HPLC analysis.

Synthesis of Compound 1900

Compound 1900 (yield of 29%) was obtained by using the same method as the synthesis method of Compound 1886 of Synthesis Example 3, except that 1-(3,5-diisopropyl-[1,1′-biphenyl]-4-yl)-2-phenyl-1H-benzo[d]imidazole was used instead of 1-methyl-2-phenyl-1H-benzo[d]imidazole. The substance was identified by Mass and HPLC analysis.

Synthesis of Compound 1994

Compound 1994 (yield of 27%) was obtained by using the same method as the synthesis method of Compound 1886 of Synthesis Example 3, except that 2-([1,1′-biphenyl]-3-yl)-1-(3,5-diisopropyl-[1,1′-biphenyl]-4-yl)-1H-benzo[d]imidazole was used instead of 1-methyl-2-phenyl-1H-benzo[d]imidazole. The substance was identified by Mass and HPLC analysis.

Synthesis of Compound 3394A

Compound 3394A (yield of 83%) was obtained by using the same method as the synthesis method of Compound 1A of Synthesis Example 1, except that 4-neopentyl-2-phenyl-5-(trimethylsilyl)pyridine was used instead of 2-phenyl-5-(trimethylsilyl)pyridine.

Synthesis of Compound 3394B

Compound 3394B was obtained by using the same method as the synthesis method of Compound 1B of Synthesis Example 1, except that Compound 3394A was used instead of Compound 1A. Obtained Compound 3394B was used in the next reaction without additional purification.

Synthesis of Compound 3394

Compound 3394 (yield of 35%) was obtained by using the same method as the synthesis method of Compound 1 of Synthesis Example 1, except that Compound 3394B was used instead of Compound 1B. The substance was identified by Mass and HPLC analysis.

Synthesis of Compound 3408

Compound 3408 (yield of 31%) was obtained by using the same method as the synthesis method of Compound 3394 of Synthesis Example 7, except that 1-(3,5-diisopropyl-[1,1′-biphenyl]-4-yl)-2-phenyl-1H-benzo[d]imidazole was used instead of 1-methyl-2-phenyl-1H-benzo[d]imidazole. The substance was identified by Mass and HPLC analysis.

Synthesis of Compound 5670A

Compound 5670A (yield of 75%) was obtained by using the same method as the synthesis method of Compound 1A of Synthesis Example 1, except that 4-isobutyl-2-phenyl-5-(trimethylgermyl)pyridine was used instead of 2-phenyl-5-(trimethylsilyl)pyridine.

Synthesis of Compound 5670B

Compound 5670B was obtained by using the same method as the synthesis method of Compound 1B of Synthesis Example 1, except that Compound 5670A was used instead of Compound 1A. Obtained Compound 5670B was used in the next reaction without additional purification.

Synthesis of Compound 5670

Compound 5670 (yield of 30%) was obtained by using the same method as the synthesis method of Compound 1 of Synthesis Example 1, except that Compound 5670B was used instead of Compound 1B, and 1-(3,5-diisopropyl-[1,1′-biphenyl]-4-yl)-2-phenyl-1H-benzo[d]imidazole was used instead of 1-methyl-2-phenyl-1H-benzo[d]imidazole. The substance was identified by Mass and HPLC analysis.

As an anode, a glass substrate with ITO patterned thereon was cut to a size of 50 mm×50 mm×0.5 mm, sonicated by using isopropyl alcohol and pure water for 5 minutes each, and then irradiated with ultraviolet light for 30 minutes and exposed to ozone for cleaning. Then, the resultant glass substrate was loaded onto a vacuum deposition apparatus.

Compound HT3 and F6-TCNNQ were vacuum-deposited at a weight ratio of 98:2 on the anode to form a hole injection layer having a thickness of 100 Å, and Compound HT3 was vacuum-deposited on the hole injection layer to form a hole transport layer having a thickness of 1,650 Å.

Subsequently, Compound CBP (host) and Compound 1 (dopant) were co-deposited at a weight ratio of 95:5 on the hole transport layer to form an emission layer having a thickness of 400 Å.

Then, Compound ET3 and ET-D1 were co-deposited at a volume ratio of 50:50 on the emission layer to form an electron transport layer having a thickness of 350 Å, ET-D1 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 on the electron injection layer to form a cathode having a thickness of 1,000 Å, thereby completing an organic light-emitting device.

Examples 2 to 9 and Comparative Examples 1 and 2

Organic light-emitting devices were manufactured in the same manner as in Example 1, except that Compounds shown in Table 3 were each used instead of Compound 1 as a dopant in forming an emission layer.

Evaluation Example 1: Characteristic Evaluation of Organic Light-Emitting Device

For each organic light-emitting device manufactured in Examples 1 to 9 and Comparative Examples 1 to 2, the maximum value of external quantum efficiency (Max EQE), roll-off ratio, and the lifespan (LT97) were evaluated. Results thereof are shown in Table 3. This evaluation was performed using a current-voltage meter (Keithley 2400) and a luminescence meter (Minolta Cs-1,000A), and the lifespan (LT97) (at 18000 nit) was evaluated by measuring the amount of time that elapsed until luminance was reduced to 97% of the initial brightness of 100%. The roll-off ratio was calculated by the following Equation 20.
Roll-off ratio={1−(efficiency(at 18000 nit)/maximum luminescence efficiency)}×100%  Equation 20

As described in Table 3, the organic light-emitting devices manufactured according to Examples 1 to 9 emit red light and have improved driving voltage, improved external quantum efficiency, improved roll-off ratio, and improved lifespan characteristics, compared to the organic light-emitting devices manufactured according to Comparative Examples 1 and 2.

The organometallic compound according to embodiments has excellent electric characteristics and thermal stability. Accordingly, an organic light-emitting device including the organometallic compound may have excellent characteristics in terms of driving voltage, luminescence efficiency, quantum luminescence efficiency, roll-off ratio, and lifespan. In particular, orientation of the organometallic compound significantly increases, and thus, quantum luminescence efficiency substantially increases.