ORGANIC METAL COMPOUND, ORGANIC LIGHT EMITTING DIODE AND ORGANIC LIGHT EMITTING DEVICE HAVING THE COMPOUND

The present disclosure relates to an organic metal compound having the following structure of Formula 1, an organic light emitting diode (OLED) and an organic light emitting device that includes the organic metal compound. The OLED and the organic light emitting device including the organic metal compound can improve their luminous efficiency, luminous color purity and lifespan.  |r(LA)m(LB)n   [Formula 1]

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit under 35 U.S.C. § 119(a) of Korean Patent Application No. 10-2020-0177156, filed in the Republic of Korea on Dec. 17, 2020, which is expressly incorporated hereby in its entirety into the present application.

BACKGROUND

Technical Field

The present disclosure relates to an organic metal compound, and more specifically, to an organic metal compound having excellent luminous efficiency and luminous lifespan, an organic light emitting diode and an organic light emitting device including the organic metal compound.

Discussion of the Related Art

An organic light emitting diode (OLED) among a flat display device used widely has come into the spotlight as a display device replacing rapidly a liquid crystal display device (LCD). The OLED can be formed as a thin organic film less than 2000 Å and can implement unidirectional or bidirectional images by electrode configurations. Also, the OLED can be formed even on a flexible transparent substrate such as a plastic substrate so that a flexible or a foldable display device can be realized with ease using the OLED. In addition, the OLED can be driven at a lower voltage and the OLED has excellent high color purity compared to the LCD.

Since fluorescent material uses only singlet exciton energy in the luminous process, the related art fluorescent material shows low luminous efficiency. On the contrary, phosphorescent material can show high luminous efficiency since it uses triplet exciton energy as well as singlet exciton energy in the luminous process. However, metal complex, representative phosphorescent material, has short luminous lifespan for commercial use. Therefore, there remains a need to develop a new compound that can enhance luminous efficiency and luminous lifespan.

SUMMARY

Accordingly, embodiments of the present disclosure are directed to an organic light emitting device that substantially obviates one or more of the problems due to the limitations and disadvantages of the related art.

An aspect of the present disclosure is to provide an organic metal compound having excellent luminous efficiency and luminous lifespan, an organic light emitting diode and an organic light emitting device including the compound.

To achieve these and other aspects of the inventive concepts, as embodied and broadly described, in one aspect, the present disclosure provides an organic metal compound having the following structure of Formula 1:

r(LA)m(LB)n[Formula 1]wherein LAhas the following structure of Formula 2; LBis an auxiliary ligand having the following structure of Formula 3; m is an integer of 1 to 3 and n is an integer of 0 to 2, wherein m+n is 3;

each of X3to X5is independently CR8or N and at least one of X3to X5is CR8;

each of X6to X9is independently is CR9or N and at least one of X6to X9is CR9;

two adjacent carbons to which R6is attached when b is an integer 2 or more, and/or

two adjacent carbons to which R8is attached, and/or

two adjacent carbons to which R9is attached

form an unsubstituted or substituted C4-C20alicyclic ring, an unsubstituted or substituted C3-C20hetero alicyclic ring, an unsubstituted or substituted C6-C30aromatic ring or an unsubstituted or substituted C3-C30hetero aromatic ring;

a is an integer of 0 to 2;

b is an integer of 0 to 4; and

a+b is no more than 4;

In another aspect, the present disclosure provides an organic light emitting diode comprises a first electrode; a second electrode facing the first electrode; and an emissive layer disposed between the first and second electrodes and including at least one emitting material layer, wherein the at least one emitting material layer includes the organic metal compound.

As an example, the organic metal compound may be comprised as dopant in the at least one emitting material layer.

The emissive layer may have single emitting part or multiple emitting parts to form a tandem structure.

In still another aspect, the present disclosure provides an organic light emitting device, for example, an organic light emitting display device or an organic light emitting illumination device, comprises a substrate and the organic light emitting diode over the substrate.

DETAILED DESCRIPTION

Reference will now be made in detail to aspects of the disclosure, examples of which are illustrated in the accompanying drawings.

Luminous material in an organic light emitting diode should have excellent luminous efficiency and luminous lifespan. An organic metal compound in accordance with the present disclosure has a rigid chemical conformation so that it has excellent luminous efficiency and luminous lifespan. The organic metal compound of the present disclosure may have the following structure of Formula 1:

|r(LA)m(LB)n[Formula 1]wherein LAhas the following structure of Formula 2; LBis an auxiliary ligand having the following structure of Formula 3; m is an integer of 1 to 3 and n is an integer of 0 to 2, wherein m+n is 3;

each of X3to X5is independently CR8or N and at least one of X3to X5is CR8;

each of X6to X9is independently is CR9or N and at least one of X6to X9is CR9;

two adjacent carbons to which R6is attached when b is an integer 2 or more, and/or

form an unsubstituted or substituted C4-C20alicyclic ring, an unsubstituted or substituted C3-C20hetero alicyclic ring, an unsubstituted or substituted C6-C30aromatic ring or an unsubstituted or substituted C3-C30hetero aromatic ring;

a is an integer of 0 to 2;

b is an integer of 0 to 4; and

a+b is no more than 4,

As used herein, the term “unsubstituted” means that hydrogen is linked, and in this case, hydrogen comprises protium, deuterium and tritium.

As used herein, substituent in the term “substituted” comprises, but is not limited to, unsubstituted or deuterium or halogen-substituted C1-C20alkyl, unsubstituted or deuterium or halogen-substituted C1-C20alkoxy, halogen, cyano, —CF3, a hydroxyl group, a carboxylic group, a carbonyl group, an amino group, a C1-C10alkyl amino group, a C6-C30aryl amino group, a C3-C30hetero aryl amino group, a C6-C30aryl group, a C3-C30hetero aryl group, a nitro group, a hydrazyl group, a sulfonate group, a C1-C20alkyl silyl group, a C6-C30aryl silyl group and a C3-C30hetero aryl silyl group.

As used herein, the term “alkenyl” is a hydrocarbon group of 2 to 20 carbon atoms containing at least one carbon-carbon double bond. The alkenyl group can be substituted with one or more substituents.

As used herein, the term “alicyclic” or “cycloalkyl” refers to non-aromatic carbon-based ring composed of at least three carbon atoms. Examples of alicyclic groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, norbornyl, and the like. The alicyclic group can be substituted with one or more substituents.

As used herein, the term “alkoxy” refers to an branched or unbranched alkyl bonded through an ether linkage represented by the formula —O(-alkyl) where alkyl is defined herein. Examples of alkoxy include methoxy, ethoxy, n-propoxy, isopropoxy, butoxy, and tert-butoxy, and the like.

As used herein, the term “aromatic” or “aryl” is well known in the art. The term includes monocyclic rings linked covalently or fused-ring polycyclic groups. An aromatic group can be unsubstituted or substituted. Examples of aromatic or aryl include phenyl, 1-naphthyl, 2-naphthyl, 4-biphenyl, anthracenyl, and phenanthracenyl and the like. Substituents for each of the above noted aryl ring systems are acceptable substituents are defined herein.

As used herein, the term “alkyl silyl group” refers to any linear or branched, saturated or unsaturated acyclic or acyclic alkyl, and the alkyl has 1 to 20 carbon atoms. Examples of the alkyl silyl group include a trimethylsilyl group, a trimethylsilyl group, a t-butyldimethylsilyl group, a vinyldimethylsilyl group, a propyldimethylsilyl group, a triphenylsilyl group, a diphenylsilyl group, and a phenylsilyl group.

As used herein, the term “halogen” refers to fluorine, chlorine, bromine or iodine atom.

As used herein, the term “hetero” in such as “hetero alkyl”, “hetero alkenyl”, “a hetero alicyclic group”, “a hetero aromatic group”, “a hetero cycloalkylene group”, “a hetero arylene group”, “a hetero aryl alkylene group”, “ a hetero aryl oxylene group”, “a hetero cycloalkyl group”, “a hetero aryl group”, “a hetero aryl alkyl group”, “a hetero aryloxyl group”, “a hetero aryl amino group” means that at least one carbon atom, for example 1-5 carbons atoms, constituting an aliphatic chain, an alicyclic group or ring or an aromatic group or ring is substituted with at least one hetero atom selected from the group consisting of N, O, S, P and combination thereof.

As used herein, the term “hetero aromatic” or “hetero aryl” refers to a heterocycles including hetero atoms selected from N, O and S in a ring where the ring system is an aromatic ring. The term includes monocyclic rings linked covalently or fused-ring polycyclic groups. A hetero aromatic group can be unsubstituted or substituted. Examples of hetero aromatic or hetero aryl include pyridyl, pyrrolyl, pyrazinyl, pyrimidinyl, thienyl (alternatively referred to as thiophenyl), thiazolyl, furanyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, oxazolyl, oxadiazolyl, thiazolyl, and thiadiazolyl.

As used herein, the term “hetero aryl oxy” refers to a group represented by the formula —O-(hetero aryl) where hetero aryl is defined herein.

In one exemplary aspect, when each of R1to R9in Formula 2 is independently a C6-C30aromatic group, each of R1to R9is independently may be, but is not limited to, a C6-C30aryl group, a C7-C30aryl alkyl group, a C6-C30aryl oxy group and a C6-C30aryl amino group. As an example, when each of R1to R9is independently a C6-C30aryl group, each of R1to R9may independently comprise, but is not limited to, an unfused or fused aryl group such as phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, pentalenyl, indenyl, indeno-indenyl, heptalenyl, biphenylenyl, indacenyl, phenalenyl, phenanthrenyl, benzo-phenanthrenyl, dibenzo-phenanthrenyl, azulenyl, pyrenyl, fluoranthenyl, triphenylenyl, chrysenyl, tetraphenylenyl, tetracenyl, pleiadenyl, picenyl, pentaphenylenyl, pentacenyl, fluorenyl, indeno-fluorenyl and spiro-fluorenyl. The unfused or fused aryl group may be substituted or unsubstituted. In some embodiments, adjacent two among R1to R5or adjacent two among R7to R9form unfused or fused aryl group may be substituted or unsubstituted.

As an example, each of the aromatic group or the hetero aromatic group of R1to R9may consist of one to three aromatic or hetero aromatic rings. When the number of the aromatic or hetero aromatic rings of R1to R9becomes more than four, conjugated structure among the within the whole molecule becomes too long, thus, the organic metal compound may have too narrow energy bandgap. For example, each of the aryl group or the hetero aryl group of R1to R9may comprise independently, but is not limited to, phenyl, biphenyl, naphthyl, anthracenyl, pyrrolyl, triazinyl, imidazolyl, pyrazolyl, pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, furanyl, benzo-furanyl, dibenzo-furanyl, thiophenyl, benzo-thiophenyl, dibenzo-thiophenyl, carbazolyl, acridinyl, carbolinyl, phenazinyl, phenoxazinyl and/or phenothiazinyl.

In one exemplary aspect, each of the alkyl, the hetero alkyl, the alkenyl, the hetero alkenyl, the alkoxy, the alkyl amino, the alkyl silyl, the alicyclic group, the hetero alicyclic group, the aromatic group and the hetero aromatic group of R1to R9may be independently unsubstituted or substituted with at least one of halogen, C1-C10alkyl, a C4-C20alicyclic group, a C3-C20hetero alicyclic group, a C6-C20aromatic group and a C3-C20hetero aromatic group. In addition, each of the C4-C20alicyclic ring, the C3-C20hetero alicyclic ring, the C6-C30aromatic ring and the C3-C30hetero aromatic ring formed by adjacent two of R1to R6, adjacent two of R8, or adjacent two of R9may be independently unsubstituted or substituted with at least one C1-C10alkyl group.

Alternatively, adjacent two of R1to R6, R8and R9may form an unsubstituted or substituted C4-C30alicyclic ring (e.g., a C5-C10alicyclic ring), an unsubstituted or substituted C3-C30hetero alicyclic ring (e.g. a C3-C10hetero alicyclic ring), an unsubstituted or substituted C6-C30aromatic ring (e.g. a C6-C20aromatic ring) or an unsubstituted or substituted C3-C30hetero aromatic ring (e.g. a C3-C20hetero aromatic ring). The alicyclic ring, the hetero alicyclic ring, the aromatic ring and the hetero aromatic ring formed by adjacent two of R1to R6, R8and R9are not limited to specific rings. For example, the aromatic ring or the hetero aromatic ring formed by those groups may comprise, but is not limited to, a benzene ring, a pyridine ring, an indole ring, a pyran ring, a fluorene ring unsubstituted or substituted with at least one C1-C10alkyl group. In some embodiments, the aromatic ring or the hetero aromatic ring formed by two adjacent elements among R1to R6, two adjacent carbons to which R8is attached or two adjacent carbons to which R9is attached may form an unsubstituted or substituted fused aromatic or heteroaromatic ring. The definitions of the fused aromatic ring and the fused heteroaromatic ring are the same as mentioned above.

The organic metal compound having the structure of Formula 1 has a hetero aromatic ligand consisting of at least 5 rings. Since the organic metal compound has a rigid chemical conformation, so that its conformation is not rotated in the luminous process, therefore, and it can maintain good luminous lifespan. The organic metal compound has specific ranges of photoluminescence emissions, so that its color purity can be improved.

In one exemplary aspect, each of m and n in Formula 1 may be 1 or 2. When the organic metal compound is a heteroleptic metal complex including two different bidentate ligands coordinated to the central metal atom, the photoluminescence color purity and emission colors of the organic metal compound can be controlled with ease by combining two different bidentate ligands. In addition, it is possible to control the color purity and emission peaks of the organic metal compound by introducing various substituents to each of the ligands. Alternatively, m may be 3 and n may be 0 in Formula 1. As an example, the organic metal compound having the structure of Formula 1 emits green color and can improve luminous efficiency of an organic light emitting diode.

In one exemplary aspect, the phenyl group in Formula 2 may be substituted to a meta position of the pyridine ring coordinated to the metal atom and each of X1and X3to X9in Formula 2 may be independently an unsubstituted or substituted carbon atom. Such LAmay have the following structure of Formula 4A or Formula 4B:

each of R1to R6and b is a same as defined in Formula 2;

two adjacent carbons to which R13is attached when d an integer of 2 or more, and/or

two adjacent carbons tow which R14is attached when e is an integer of 2 or more

form an unsubstituted or substituted C4-C20alicyclic ring, an unsubstituted or substituted C3-C20hetero alicyclic ring, an unsubstituted or substituted C6-C30aromatic ring or an unsubstituted or substituted C3-C30hetero aromatic ring when each of d and e is an integer of two or more;

c is an integer of 0 or 1

d is an integer of 0 to 3; and

e is an integer of 0 to 4.

In another exemplary aspect, the phenyl group in Formula 2 may be substituted to a para position of the pyridine ring coordinated to the metal atom and each of X1and X3to X9in Formula 2 may be independently an unsubstituted or substituted carbon atom. Such LAmay have the following structure of Formula 4C or Formula 4D:

each of R1to R6and b is a same as defined in Formula 2;

two adjacent carbons to which R13is attached when d an integer of 2 or more, and/or

two adjacent carbons to which R14is attached when e is an integer of 2 or more

form an unsubstituted or substituted C4-C20alicyclic ring, an unsubstituted or substituted C3-C20hetero alicyclic ring, an unsubstituted or substituted C6-C30aromatic ring or an unsubstituted or substituted C3-C30hetero aromatic ring;

c is an integer of 0 or 1;

d is an integer of 0 to 3; and

e is an integer of 0 to 4.

In one exemplary aspect, each of the alkyl, the hetero alkyl, the alkenyl, the hetero alkenyl, the alkoxy, the alkyl amino, the alkyl silyl, the alicyclic group, the hetero alicyclic group, the aromatic group and the hetero aromatic group of R1to R6and R11to R14in Formulae 4A to 4D may be independently unsubstituted or substituted with at least one of deuterium, tritium, halogen, C1-C10alkyl, a C4-C20alicyclic group, a C3-C20hetero alicyclic group, a C6-C20aromatic group and a C3-C20hetero aromatic group. In addition, each of the C4-C20alicyclic ring, the C3-C20hetero alicyclic ring, the C6-C30aromatic ring and the C3-C30hetero aromatic ring formed by adjacent two of R1to R6, R13and R14in Formulae 4A to 4D may be independently unsubstituted or substituted with at least one C1-C10alkyl group.

In still another exemplary aspect, LBas the auxiliary ligand may be a phenyl-pyridino-based ligand or an acetylacetonate-based ligand. As an example, LBmay have, but is not limited to, the following structure of Formula 5A or Formula 5B:

two adjacent carbons to which R21is attached when f is an integer of 2 or more, and/or

two adjacent carbons to which R22is attached when g is an integer of 2 or more, and/or

form an unsubstituted or substituted C4-C20alicyclic ring, an unsubstituted or substituted C3-C20hetero alicyclic ring, an unsubstituted or substituted C6-C30aromatic ring or an unsubstituted or substituted C3-C30hetero aromatic ring;

each of f and g is an integer of 0 to 4.

The substituents of R21to R22and R31to R33or the ring formed by R21to R22and R31to R33may be identical to the substituents or the ring as described in Formula 2. In one exemplary aspect, the organic metal compound having the structure of Formulae 1 to 5B may be selected from, but is not limited to, the following organic metal compounds of Formula 6:

The organic metal compound having anyone of the structures of Formula 4A to Formula 6 includes a hetero aromatic ligand consisting of at least 5 rings, so it has a rigid chemical conformation. The organic metal compound can improve its color purity and luminous lifespan because it can maintain its stable chemical conformation in the emission process. In addition, since the organic metal compound may be a metal complex with bidentate ligands, it is possible to control the emission color purity and emission colors with ease. Accordingly, an organic light emitting diode having excellent luminous efficiency by applying the organic metal compound having the structure of Formulae 1 to 6 into an emissive layer.

[Organic Light Emitting Device and Organic Light Emitting Diode]

It is possible to realize an OLED having reduced driving voltage and excellent luminous efficiency and improved luminous lifespan by applying the organic compound having the structure of Formulae 1 to 6 into an emissive layer, for example an emitting material layer of the OLED. The OLED of the present disclosure may be applied to an organic light emitting device such as an organic light emitting display device or an organic light emitting illumination device. An organic light emitting display device including the OLED will be explained.

FIG. 1is a schematic circuit diagram illustrating an organic light emitting display device in accordance with an exemplary aspect of the present disclosure. As illustrated inFIG. 1, a gate line GL, a data line DL and power line PL, each of which cross each other to define a pixel region P, in the organic light display device. A switching thin film transistor Ts, a driving thin film transistor Td, a storage capacitor Cst and an organic light emitting diode D are formed within the pixel region P. The pixel region P may include a red (R) pixel region, a green (G) pixel region and a blue (B) pixel region.

The switching thin film transistor Ts is connected to the gate line GL and the data line DL, and the driving thin film transistor Td and the storage capacitor Cst are connected between the switching thin film transistor Ts and the power line PL. The organic light emitting diode D is connected to the driving thin film transistor Td. When the switching thin film transistor Ts is turned on by a gate signal applied into the gate line GL, a data signal applied into the data line DL is applied into a gate electrode of the driving thin film transistor Td and one electrode of the storage capacitor Cst through the switching thin film transistor Ts.

The driving thin film transistor Td is turned on by the data signal applied into the gate electrode so that a current proportional to the data signal is supplied from the power line PL to the organic light emitting diode D through the driving thin film transistor Td. And then, the organic light emitting diode D emits light having a luminance proportional to the current flowing through the driving thin film transistor Td. In this case, the storage capacitor Cst is charge with a voltage proportional to the data signal so that the voltage of the gate electrode in the driving thin film transistor Td is kept constant during one frame. Therefore, the organic light emitting display device can display a desired image.

FIG. 2is a schematic cross-sectional view illustrating an organic light emitting display device in accordance with an exemplary aspect of the present disclosure. As illustrated inFIG. 2, the organic light emitting display device100comprises a substrate102, a thin-film transistor Tr over the substrate102, and an organic light emitting diode D connected to the thin film transistor Tr. As an example, the substrate102defines a red pixel region, a green pixel region and a blue pixel region and the organic light emitting diode D is located in each pixel region. In other words, the organic light emitting diode D, each of which emits red, green or blue light, is located correspondingly in the red pixel region, the green pixel region and the blue pixel region.

The substrate102may include, but is not limited to, glass, thin flexible material and/or polymer plastics. For example, the flexible material may be selected from the group, but is not limited to, polyimide (PI), polyethersulfone (PES), polyethylenenaphthalate (PEN), polyethylene terephthalate (PET), polycarbonate (PC) and combination thereof. The substrate102, over which the thin film transistor Tr and the organic light emitting diode D are arranged, forms an array substrate.

A buffer layer106may be disposed over the substrate102, and the thin film transistor Tr is disposed over the buffer layer106. The buffer layer106may be omitted.

A semiconductor layer110is disposed over the buffer layer106. In one exemplary aspect, the semiconductor layer110may include, but is not limited to, oxide semiconductor materials. In this case, a light-shield pattern may be disposed under the semiconductor layer110, and the light-shield pattern can prevent light from being incident toward the semiconductor layer110, and thereby, preventing the semiconductor layer110from being deteriorated by the light. Alternatively, the semiconductor layer110may include polycrystalline silicon. In this case, opposite edges of the semiconductor layer110may be doped with impurities.

A gate insulating layer120including an insulating material is disposed on the semiconductor layer110. The gate insulating layer120may include, but is not limited to, an inorganic insulating material such as silicon oxide (SiOx, wherein 0≤x≤2) or silicon nitride (SiNx, wherein 0≤x≤2).

A gate electrode130made of a conductive material such as a metal is disposed over the gate insulating layer120so as to correspond to a center of the semiconductor layer110. While the gate insulating layer120is disposed over a whole area of the substrate102inFIG. 2, the gate insulating layer120may be patterned identically as the gate electrode130.

An interlayer insulating layer140including an insulating material is disposed on the gate electrode130with covering over an entire surface of the substrate102. The interlayer insulating layer140may include an inorganic insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx), or an organic insulating material such as benzocyclobutene or photo-acryl.

The interlayer insulating layer140has first and second semiconductor layer contact holes142and144that expose both sides of the semiconductor layer110. The first and second semiconductor layer contact holes142and144are disposed over opposite sides of the gate electrode130with spacing apart from the gate electrode130. The first and second semiconductor layer contact holes142and144are formed within the gate insulating layer120inFIG. 2. Alternatively, the first and second semiconductor layer contact holes142and144are formed only within the interlayer insulating layer140when the gate insulating layer120is patterned identically as the gate electrode130.

A source electrode152and a drain electrode154, which are made of conductive material such as a metal, are disposed on the interlayer insulating layer140. The source electrode152and the drain electrode154are spaced apart from each other with respect to the gate electrode130, and contact both sides of the semiconductor layer110through the first and second semiconductor layer contact holes142and144, respectively.

The semiconductor layer110, the gate electrode130, the source electrode152and the drain electrode154constitute the thin film transistor Tr, which acts as a driving element. The thin film transistor Tr inFIG. 2has a coplanar structure in which the gate electrode130, the source electrode152and the drain electrode154are disposed over the semiconductor layer110. Alternatively, the thin film transistor Tr may have an inverted staggered structure in which a gate electrode is disposed under a semiconductor layer and a source and drain electrodes are disposed over the semiconductor layer. In this case, the semiconductor layer may include amorphous silicon.

Although not shown inFIG. 2, a gate line and a data line, which cross each other to define a pixel region, and a switching element, which is connected to the gate line and the data line, is may be further formed in the pixel region. The switching element is connected to the thin film transistor Tr, which is a driving element. In addition, a power line is spaced apart in parallel from the gate line or the data line, and the thin film transistor Tr may further include a storage capacitor configured to constantly keep a voltage of the gate electrode for one frame.

A passivation layer160is disposed on the source and drain electrodes152and154with covering the thin film transistor Tr over the whole substrate102. The passivation layer160has a flat top surface and a drain contact hole162that exposes the drain electrode154of the thin film transistor Tr. While the drain contact hole162is disposed on the second semiconductor layer contact hole144, it may be spaced apart from the second semiconductor layer contact hole144.

The organic light emitting diode D (OLED D) includes a first electrode210that is disposed on the passivation layer160and connected to the drain electrode154of the thin film transistor Tr. The organic light emitting diode D further includes an emissive layer230and a second electrode220each of which is disposed sequentially on the first electrode210.

The first electrode210is disposed in each pixel region. The first electrode210may be an anode and include conductive material having relatively high work function value. For example, the first electrode210may include, but is not limited to, a transparent conductive oxide (TCO) such as indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), SnO, ZnO, indium cerium oxide (ICO), aluminum doped zinc oxide (AZO), and the like.

In one exemplary aspect, when the organic light emitting display device100is a bottom-emission type, the first electrode201may have a single-layered structure of the TCO. Alternatively, when the organic light emitting display device100is a top-emission type, a reflective electrode or a reflective layer may be disposed under the first electrode210. For example, the reflective electrode or the reflective layer may include, but are not limited to, silver (Ag) or aluminum-palladium-copper (APC) alloy. In the OLED D of the top-emission type, the first electrode210may have a triple-layered structure of ITO/Ag/ITO or ITO/APC/ITO.

In addition, a bank layer164is disposed on the passivation layer160in order to cover edges of the first electrode210. The bank layer164exposes a center of the first electrode210corresponding to each pixel region. The bank layer164may be omitted.

An emissive layer230is disposed on the first electrode210. In one exemplary aspect, the emissive layer230may have a single-layered structure of an emitting material layer (EML). Alternatively, the emissive layer230may have a multiple-layered structure of a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), an EML, a hole blocking layer (HBL), an electron transport layer (ETL) and/or an electron injection layer (EIL) (see,FIGS. 3, 5 and 6). In one aspect, the emissive layer230may have single emitting part. Alternatively, the emissive layer230may have multiple emitting parts to form a tandem structure.

The emissive layer230may comprise the organic metal compound having the structure of Formulae 1 to 6. The emissive layer230including the organic metal compound enables the OLED D and the organic light emitting device100to improve their luminous efficiency and luminous lifespan considerably.

The second electrode220is disposed over the substrate102above which the emissive layer230is disposed. The second electrode220may be disposed over a whole display area, and may include a conductive material with a relatively low work function value compared to the first electrode210, and may be a cathode. For example, the second electrode220may include, but is not limited to, aluminum (Al), magnesium (Mg), calcium (Ca), silver (Ag), alloy thereof or combination thereof such as aluminum-magnesium alloy (Al—Mg). When the organic light emitting display device100is a top-emission type, the second electrode220is thin so as to have light-transmissive (semi-transmissive) property.

In addition, an encapsulation film170may be disposed over the second electrode220in order to prevent outer moisture from penetrating into the organic light emitting diode D. The encapsulation film170may have, but is not limited to, a laminated structure of a first inorganic insulating film172, an organic insulating film174and a second inorganic insulating film176. The encapsulation film170may be omitted.

A polarizing plate may be attached onto the encapsulation film to reduce reflection of external light. For example, the polarizing plate may be a circular polarizing plate. When the organic light emitting display device100is a bottom-emission type, the polarizer may be disposed under the substrate100. Alternatively, when the organic light emitting display device100is a top-emission type, the polarizer may be disposed over the encapsulation film170. In addition, a cover window may be attached to the encapsulation film170or the polarizer. In this case, the substrate110and the cover window may have a flexible property, thus the organic light emitting display device100may be a flexible display device.

Next, we will describe the OLED D including the organic metal compound in more detail.FIG. 3is a schematic cross-sectional view illustrating an organic light emitting diode having a single emitting part in accordance with an exemplary embodiment of the present disclosure. As illustrated inFIG. 3, the organic light emitting diode D1(OLED D1) in accordance with the present disclosure includes first and second electrodes210and220facing each other and an emissive layer230disposed between the first and second electrodes210and220. The organic light emitting display device100includes a red pixel region, a green pixel region and a blue pixel region, and the OLED D1may be disposed in the green pixel region.

In an exemplary embodiment, the emissive layer230includes an emitting material layer (EML)340disposed between the first and second electrodes210and220. Also, the emissive layer230may comprise at least one of an HTL320disposed between the first electrode210and the EML340and an ETL360disposed between the second electrode220and the EML340. In addition, the emissive layer230may further comprise at least one of an HIL310disposed between the first electrode210and the HTL320and an EIL370disposed between the second electrode220and the ETL360. Alternatively, the emissive layer320may further comprise a first exciton blocking layer, i.e. an EBL330disposed between the HTL320and the EML340and/or a second exciton blocking layer, i.e. a HBL350disposed between the EML340and the ETL360.

The first electrode210may be an anode that provides a hole into the EML340. The first electrode210may include a conductive material having a relatively high work function value, for example, a transparent conductive oxide (TCO). In an exemplary embodiment, the first electrode210may include, but is not limited to, ITO, IZO, ITZO, SnO, ZnO, ICO, AZO, and the like.

The second electrode220may be a cathode that provides an electron into the EML340. The second electrode220may include a conductive material having a relatively low work function values, i.e., a highly reflective material such as Al, Mg, Ca, Ag, alloy thereof or combination thereof such as Al—Mg.

The EML340may comprise a host (first host) and a dopant (first dopant)342in which substantial emission is occurred. As an example, the EML340may emit green colors. For example, the organic metal compound having the structure of Formulae 1 to 6 may be used as the dopant342in the EML340.

The ETL360and the EIL370may be laminated sequentially between the EML340and the second electrode220. The ETL360includes a material having high electron mobility so as to provide electrons stably with the EML340by fast electron transportation.

The EIL370is disposed between the second electrode220and the ETL360, and can improve physical properties of the second electrode220and therefore, can enhance the lifetime of the OLED D1. In one exemplary aspect, the EIL370may comprise, but is not limited to, an alkali metal halide or an alkaline earth metal halide such as LiF, CsF, NaF, BaF2and the like, and/or an organic metal compound such as Liq, lithium benzoate, sodium stearate, and the like. Alternatively, the EIL370may be omitted.

In an alternative aspect, the electron transport material and the electron injection material may be admixed to form a single ETL-EIL. The electron transport material and the electron injection material may be mixed with, but is not limited to, about 4:1 to about 1:4 by weight, for example, about 2:1 to about 1:2.

When holes are transferred to the second electrode220via the EML340and/or electrons are transferred to the first electrode210via the EML340, the OLED D1may have short lifetime and reduced luminous efficiency. In order to prevent these phenomena, the OLED D1in accordance with this aspect of the present disclosure may have at least one exciton blocking layer adjacent to the EML340.

In addition, the OLED D1may further include the HBL350as a second exciton blocking layer between the EML340and the ETL360so that holes cannot be transferred from the EML340to the ETL360. In one exemplary aspect, the HBL350may comprise, but is not limited to, at least one of oxadiazole-based compounds, triazole-based compounds, phenanthroline-based compounds, benzoxazole-based compounds, benzothiazole-based compounds, benzimidazole-based compounds, and triazine-based compounds each of which can be used in the ETL360.

For example, the HBL350may comprise a compound having a relatively low HOMO energy level compared to the luminescent materials in EML340. The HBL350may comprise, but is not limited to, Alq3, BAlq, Liq, PBD, spiro-PBD, BCP, Bis-4,5-(3,5-di-3-pyridylphenyl)-2-methylpyrimidine (B3PYMPM), bis[2-(diphenylphosphino)phenyl]ether oxide (DPEPO), 9-(6-(9H-carbazol-9-yl)pyridine-3-yl)-9H-3,9′-bicarbazole, Diphenyl[4-(triphenylsilyl)phenyl]phosphine oxide (TSPO1) and combination thereof.

As described above, the EML340may comprise the host and the dopant342. The dopant342may comprise the organic metal compound having the structure of Formulae 1 to 6.

As described above, since the organic metal compound having the structure of Formulae 1 to 6 has a rigid chemical conformation, it can show excellent color purity and luminous lifespan with maintaining its stable chemical conformation in the luminous process. Changing the structure of the bidentate ligands and substituents to the ligand allows the organic metal compound to control its luminescent color. Accordingly, the OLED D1can lower its driving voltage and improve its luminous efficiency and luminous lifespan.

In the above exemplary first aspect, the OLED and the organic light emitting display device include single emitting part emitting green color. Alternatively, the OLED may include multiple emitting parts (see,FIG. 5) each of which includes an emitting material layer having the organic metal compound having the structure of Formulae 1 to 6.

In another exemplary aspect, an organic light emitting display device can implement full-color including white color.FIG. 4is a schematic cross-sectional view illustrating an organic light emitting display device in accordance with another exemplary aspect of the present disclosure.

As illustrated inFIG. 4, the organic light emitting display device400comprises a first substrate402that defines each of a red pixel region RP, a green pixel region GP and a blue pixel region BP, a second substrate404facing the first substrate402, a thin film transistor Tr over the first substrate402, an organic light emitting diode D disposed between the first and second substrates402and404and emitting white (W) light and a color filter layer480disposed between the organic light emitting diode D and the second substrate404.

Each of the first and second substrates402and404may include, but is not limited to, glass, flexible material and/or polymer plastics. For example, each of the first and second substrates402and404may be made of PI, PES, PEN, PET, PC and combination thereof. The first substrate402, over which a thin film transistor Tr and an organic light emitting diode D are arranged, forms an array substrate.

A buffer layer406may be disposed over the first substrate402, and the thin film transistor Tr is disposed over the buffer layer406correspondingly to each of the red pixel region RP, the green pixel region GP and the blue pixel region BP. The buffer layer406may be omitted.

A semiconductor layer410is disposed over the buffer layer406. The semiconductor layer410may be made of oxide semiconductor material or polycrystalline silicon.

A gate insulating layer420including an insulating material, for example, inorganic insulating material such as silicon oxide (SiOx, wherein 0≤x≤2) or silicon nitride (SiNx, wherein 0≤x≤2) is disposed on the semiconductor layer410.

A gate electrode430made of a conductive material such as a metal is disposed over the gate insulating layer420so as to correspond to a center of the semiconductor layer410. An interlayer insulting layer440including an insulating material, for example, inorganic insulating material such as SiOxor SiNx, or an organic insulating material such as benzocyclobutene or photo-acryl, is disposed on the gate electrode430.

The interlayer insulating layer440has first and second semiconductor layer contact holes442and444that expose both sides of the semiconductor layer410. The first and second semiconductor layer contact holes442and444are disposed over opposite sides of the gate electrode430with spacing apart from the gate electrode430.

A source electrode452and a drain electrode454, which are made of a conductive material such as a metal, are disposed on the interlayer insulating layer440. The source electrode452and the drain electrode454are spaced apart from each other with respect to the gate electrode430, and contact both sides of the semiconductor layer410through the first and second semiconductor layer contact holes442and444, respectively.

The semiconductor layer410, the gate electrode430, the source electrode452and the drain electrode454constitute the thin film transistor Tr, which acts as a driving element.

Although not shown inFIG. 4, a gate line and a data line, which cross each other to define a pixel region, and a switching element, which is connected to the gate line and the data line, is may be further formed in the pixel region. The switching element is connected to the thin film transistor Tr, which is a driving element. In addition, a power line is spaced apart in parallel from the gate line or the data line, and the thin film transistor Tr may further include a storage capacitor configured to constantly keep a voltage of the gate electrode for one frame.

A passivation layer460is disposed on the source and drain electrodes452and454with covering the thin film transistor Tr over the whole first substrate402. The passivation layer460has a drain contact hole462that exposes the drain electrode454of the thin film transistor Tr.

The OLED D is located over the passivation layer460. The OLED D includes a first electrode510that is connected to the drain electrode454of the thin film transistor Tr, a second electrode520facing from the first electrode510and an emissive layer530disposed between the first and second electrodes510and520.

The first electrode510formed for each pixel region may be an anode and may include a conductive material having relatively high work function value. For example, the first electrode510may include, ITO, IZO, ITZO, SnO, ZnO, ICO, AZO, and the like. Alternatively, a reflective electrode or a reflective layer may be disposed under the first electrode510. For example, the reflective electrode or the reflective layer may include, but is not limited to, Ag or APC alloy.

A bank layer464is disposed on the passivation layer460in order to cover edges of the first electrode510. The bank layer464exposes a center of the first electrode510corresponding to each of the red pixel RP, the green pixel GP and the blue pixel BP. The bank layer464may be omitted.

An emissive layer530that may include emitting parts is disposed on the first electrode510. As illustrated inFIGS. 5 and 6, the emissive layer530may include multiple emitting parts600,700,700A and800and at least one charge generation layer680and780. Each of the emitting parts600,700,700A and800includes at least one emitting material layer and may further include a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer and/or an electron injection layer.

The second electrode520is disposed over the first substrate402above which the emissive layer530is disposed. The second electrode520may be disposed over a whole display area, and may include a conductive material with a relatively low work function value compared to the first electrode510, and may be a cathode. For example, the second electrode520may include, but is not limited to, Al, Mg, Ca, Ag, alloy thereof or combination thereof such as Al—Mg.

Since the light emitted from the emissive layer530is incident to the color filter layer480through the second electrode520in the organic light emitting display device400in accordance with the second embodiment of the present disclosure, the second electrode520has a thin thickness so that the light can be transmitted.

The color filter layer480is disposed over the OLED D and includes a red color filter482, a green color filter484and a blue color filter486each of which is disposed correspondingly to the red pixel RP, the green pixel GP and the blue pixel BP, respectively. Although not shown inFIG. 4, the color filter layer480may be attached to the OLED D through an adhesive layer. Alternatively, the color filter layer480may be disposed directly on the OLED D.

In addition, an encapsulation film may be disposed over the second electrode520in order to prevent outer moisture from penetrating into the OLED D. The encapsulation film may have, but is not limited to, a laminated structure of a first inorganic insulating film, an organic insulating film and a second inorganic insulating film (see,170inFIG. 2). In addition, a polarizing plate may be attached onto the second substrate404to reduce reflection of external light. For example, the polarizing plate may be a circular polarizing plate.

InFIG. 4, the light emitted from the OLED D is transmitted through the second electrode520and the color filter layer480is disposed over the OLED D. Alternatively, the light emitted from the OLED D is transmitted through the first electrode510and the color filter layer480may be disposed between the OLED D and the first substrate402. In addition, a color conversion layer may be formed between the OLED D and the color filter layer480. The color conversion layer may include a red color conversion layer, a green color conversion layer and a blue color conversion layer each of which is disposed correspondingly to each pixel (RP, GP and BP), respectively, so as to covert the white (W) color light to each of a red, green and blue color lights, respectively. Alternatively, the organic light emitting display device400may comprise the color conversion film instead of the color filter layer480.

As described above, the white (W) color light emitted from the OLED D is transmitted through the red color filter482, the green color filter484and the blue color filter486each of which is disposed correspondingly to the red pixel region RP, the green pixel region GP and the blue pixel region BP, respectively, so that red, green and blue color lights are displayed in the red pixel region RP, the green pixel region GP and the blue pixel region BP.

FIG. 5is a schematic cross-sectional view illustrating an organic light emitting diode having a tandem structure of two emitting parts. As illustrated inFIG. 5, the organic light emitting diode D2(OLED D2) in accordance with the exemplary embodiment of includes first and second electrodes510and520and an emissive layer530disposed between the first and second electrodes510and520. The emissive layer530includes a first emitting part600disposed between the first and second electrodes510and520, a second emitting part700disposed between the first emitting part600and the second electrode520and a charge generation layer (CGL)680disposed between the first and second emitting parts600and700.

The first electrode510may be an anode and may include a conductive material having relatively high work function value. For example, the first electrode510may include, ITO, IZO, ITZO, SnO, ZnO, ICO, AZO, and the like. The second electrode520may be a cathode and may include a conductive material with a relatively low work function value. For example, the second electrode520may include, but is not limited to, Al, Mg, Ca, Ag, alloy thereof or combination thereof such as Al—Mg.

The first emitting part600comprise a first EML (EML1)640. The first emitting part600may further comprise at least one of an HIL610disposed between the first electrode510and the EML1640, a first HTL (HTL1)620disposed between the HIL610and the EML1640, a first ETL (ETL1)660disposed between the EML1640and the CGL680. Alternatively, the first emitting part600may further comprise a first EBL (EBL1)630disposed between the HTL1620and the EML1640and/or a first HBL (HBL1)650disposed between the EML1640and the ETL1660.

The second emitting part700comprise a second EML (EML2)740. The second emitting part700may further comprise at least one of a second HTL (HTL2)720disposed between the CGL680and the EML2740, a second ETL (ETL2)760disposed between the second electrode520and the EML2740and an EIL770disposed between the second electrode520and the ETL2760. Alternatively, the second emitting part700may further comprise a second EBL (EBL2)730disposed between the HTL2720and the EML2740and/or a second HBL (HBL2)750disposed between the EML2740and the ETL2760.

At least one of the EML1640and the EML2740may comprise the organic metal compound having the structure of Formulae 1 to 6 to emit green color. The other of the EML1640and the EML2740may emit a blue color so that the OLED D2can realize white (W) emission. Hereinafter, the OLED D2where the EML2740includes the organic metal compound having the structure of Formulae 1 to 6 will be described in detail.

The HIL610is disposed between the first electrode510and the HTL1620and improves an interface property between the inorganic first electrode510and the organic HTL1620. In one exemplary embodiment, the HIL610may include, but is not limited to, MTDATA, NATA, 1T-NATA, 2T-NATA, CuPc, TCTA, NPB (NPD), HAT-CN, TDAPB, PEDOT/PSS, F4TCNQ, N-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine, NPNPB and combination thereof. The HIL610may be omitted in compliance of the OLED D2property.

The EIL770is disposed between the second electrode520and the ETL2760, and can improve physical properties of the second electrode520and therefore, can enhance the lifetime of the OLED D2. In one exemplary aspect, the EIL770may comprise, but is not limited to, an alkali metal halide or an alkaline earth metal halide such as LiF, CsF, NaF, BaF2and the like, and/or an organic metal compound such as Liq, lithium benzoate, sodium stearate, and the like.

Each of the HBL1650and the HBL2750may comprise, but is not limited to, at least one of oxadiazole-based compounds, triazole-based compounds, phenanthroline-based compounds, benzoxazole-based compounds, benzothiazole-based compounds, benzimidazole-based compounds, and triazine-based compounds each of which can be used in the ETL1660and the ETL2760. For example, each of the HBL1650and the HBL2750may independently comprise, but is not limited to, Alq3, BAlq, Liq, PBD, spiro-PBD, BCP, B3PYMPM, DPEPO, 9-(6-(9H-carbazol-9-yl)pyridine-3-yl)-9H-3,9′-bicarbazole, TSPO1 and combination thereof, respectively.

The CGL680is disposed between the first emitting part600and the second emitting part700. The CGL680includes an N-type CGL (N-CGL)685disposed adjacently to the first emitting part600and a P-type CGL (P-CGL)690disposed adjacently to the second emitting part700. The N-CGL685transports electrons to the EML1640of the first emitting part600and the P-CGL690transport holes to the EML2740of the second emitting part700.

The N-CGL685may be an organic layer doped with an alkali metal such as Li, Na, K and Cs and/or an alkaline earth metal such as Mg, Sr, Ba and Ra. The host in the N-CGL685may comprise, but is not limited to, Bphen and MTDATA. The contents of the alkali metal or the alkaline earth metal in the N-CGL685may be between about 0.01 wt % and about 30 wt %.

The P-CGL690may comprise, but is not limited to, inorganic material selected from the group consisting of WOx, MoOx, V2O5and combination thereof and/or organic material selected from the group consisting of NPD, HAT-CN, F4TCNQ, TPD, N,N,N′,N′-tetranaphthalenyl-benzidine (TNB), TCTA, N,N′-dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C8) and combination thereof.

The EML1640may be a blue EML. In this case, the EML1640may be a blue EML, a sky-blue EML or a deep-blue EML. The EML1640may include a host and a blue dopant. The host may be identical to the first host and the blue dopant may comprise at least one of blue phosphorescent material, blue fluorescent material and blue delayed fluorescent material.

The EML2740may comprise a lower EML740A disposed between the EBL2730and the HBL2750and an upper EML740B disposed between the lower EML740A and the HBL2750. One of the lower EML740A and the upper EML740B may emit red color and the other of the lower EML740A and the upper EML740B may emit green color. Hereinafter, the EML2740where the lower EML740A emits green color and the upper EML740B emits red color will be described in detail.

The lower EML740A includes a first host and a first dopant742. The first host may comprise, but is not limited to, mCP-CN, CBP, mCBP, mCP, DPEPO, PPT, TmPyPB, PYD-2Cz, DCzDBT, DCzTPA, pCzB-2CN), mCzB-2CN, TSPO1, CCP, 4-(3-(triphenylen-2-yl)phenyl)dibenzo[b,d]thiophene, 9-(4-(9H-carbazol-9-yl)phenyl)-9H-3,9′-bicarbazole, 9-(3-(9H-carbazol-9-yl)phenyl)-9H-3,9′-bicarbazole, 9-(6-(9H-carbazol-9-yl)pyridin-3-yl)-9H-3,9′-bicabazole, BCzPh, TCP, TCTA, CDBP, DMFL-CBP, Spiro-CBP, TCz1 and combination thereof. The first dopant742may include the organic metal compound having the structure of Formulae 1 to 6 to emit green color. For example, the contents of the first dopant742in the lower EML740A may be between about 1 wt % to about 50 wt %, for example, about 1 wt % and about 30 wt %.

The upper EML740B includes a host and a red dopant. The host may be identical to the first host and the red dopant may comprise at least one of red phosphorescent material, red florescent material and red delayed fluorescent material.

The OLED D2in accordance with this aspect has a tandem structure and includes the organic metal compound having the structure of Formulae 1 to 6. The OLED D2including the organic metal compound with excellent thermal property, a rigid chemical conformation and adjustable luminescent colors can lower its driving voltage and improve its luminous efficiency and luminous lifespan.

The OLED may have three or more emitting parts to form a tandem structure.FIG. 6is a schematic cross-sectional view illustrating an organic light emitting diode in accordance with still another exemplary aspect of the present disclosure. As illustrated inFIG. 6, the organic light emitting diode D3(OLED D3) includes first and second electrodes510and520facing each other and an emissive layer530A disposed between the first and second electrodes510and520. The emissive layer530A includes a first emitting part600disposed between the first and second electrodes510and520, a second emitting part700A disposed between the first emitting part600and the second electrode520, a third emitting part800disposed between the second emitting part700A and the second electrode520, a first charge generation layer (CGL1)680disposed between the first and second emitting parts600and700A, and a second charge generation layer (CGL2)780disposed between the second and third emitting parts700A and800.

The first emitting part600comprise a first EML (EML1)640. The first emitting part600may further comprise at least one of an HIL610disposed between the first electrode510and the EML1640, a first HTL (HTL1)620disposed between the HIL610and the EML1640, a first ETL (ETL1)660disposed between the EML1640and the CGL680. Alternatively, the first emitting part600may further comprise a first EBL (EBL1)630disposed between the HTL1620and the EML1640and/or a first HBL (HBL1)650disposed between the EML1640and the ETL1660.

The second emitting part700A comprise a second EML (EML2)740. The second emitting part700A may further comprise at least one of a second HTL (HTL2)720disposed between the CGL1680and the EML2740and a second ETL (ETL2)760disposed between the second electrode520and the EML2740. Alternatively, the second emitting part700A may further comprise a second EBL (EBL2)730disposed between the HTL2720and the EML2740and/or a second HBL (HBL2)750disposed between the EML2740and the ETL2760.

The third emitting part800comprise a third EML (EML3)840. The third emitting part800may further comprise at least one of a third HTL (HTL3)820disposed between the CGL2780and the EML3840, a third ETL (ETL3)860disposed between the second electrode520and the EML3840and an EIL870disposed between the second electrode520and the ETL3860. Alternatively, the third emitting part800may further comprise a third EBL (EBL3)830disposed between the HTL3820and the EML3840and/or a third HBL (HBL3)850disposed between the EML3840and the ETL3860.

At least one of the EML1640, the EML2740and the EML3840may comprise the organic metal compound having the structure of Formulae 1 to 6. For example, one of the EML1640, the EML2740and the EML3840may emit green color. In addition, another of the EML1640, the EML2740and the EML3840emit a blue color so that the OLED D3can realize white emission. Hereinafter, the OLED where the EML2740includes the organic metal compound having the structure of Formulae 1 to 6 to emit green color and each of the EML1640and the EML3840emits a blue light will be described in detail.

The CGL1680is disposed between the first emitting part600and the second emitting part700A and the CGL2780is disposed between the second emitting part700A and the third emitting part800. The CGL1680includes a first N-type CGL (N-CGL1)685disposed adjacently to the first emitting part600and a first P-type CGL (P-CGL1)690disposed adjacently to the second emitting part700A. The CGL2780includes a second N-type CGL (N-CGL2)785disposed adjacently to the second emitting part700A and a second P-type CGL (P-CGL2)790disposed adjacently to the third emitting part800. Each of the N-CGL1685and the N-CGL2785transports electrons to the EML1640of the first emitting part600and the EML2740of the second emitting part700A, respectively, and each of the P-CGL1690and the P-CGL2790transport holes to the EML2740of the second emitting part700A and the EML3840of the third emitting part800, respectively.

Each of the EML1640and the EML3840may be independently a blue EML. In this case, the each of the EML1640and the EML3840may be independently a blue EML, a sky-blue EML or a deep-blue EML. Each of the EML1640and the EML3840may include independently a host and a blue dopant. The host may be identical to the first host and the blue dopant may comprise at least one of blue phosphorescent material, blue fluorescent material and blue delayed fluorescent material. In one exemplary aspect, the blue dopant in the EML1640may have different color and luminous efficiency from the blue dopant in the EML3840.

The EML2740may comprise a lower EML740A disposed between the EBL2730and the HBL2750and an upper EML740B disposed between the lower EML740A and the HBL2750. One of the lower EML740A and the upper EML740B may emit red color and the other of the lower EML740A and the upper EML740B may emit green color. Hereinafter, the EML2740where the lower EML740A emits green color and the upper EML740B emits red color will be described in detail.

The lower EML740A may include a first host and a first dopant742. As an example, the first dopant742includes the organic metal compound having the structure of Formulae 1 to 6 to emit green color. For example, the contents of the dopant742in the upper EML740A may be between about 1 wt % to about 50 wt %, for example, about 1 wt % and about 30 wt %.

The upper EML740B includes a host and a red dopant. The host may be identical to the first host and the red dopant may include at least one of red phosphorescent material, red fluorescent material and red delayed fluorescent material.

The OLED D3in accordance with this aspect includes the organic metal compound having the structure of Formulae 1 to 6 in at least one emitting material layer. The organic metal compound has can maintain its stable chemical conformations in the luminescent process. The OLED including the organic metal compound and having three emitting parts can realize white luminescence with improved luminous efficiency, color purity and luminous lifespan.

SYNTHESIS EXAMPLE 1

Synthesis of Compound 1

(1) Synthesis of Intermediate A-1

Compound SM-1 (7.34 g, 20 mmol), Compound SM-2 (2.27 g, 20 mmol), Tetrakis(triphenylphosphine)palladium(0) (Pd(PPh3)4, 1.2 g, 1 mmol), K2CO3(8.3 g, 60 mmol) and a mixed solvent of toluene (200 mL) and water (50 mL) were put into a 500 mL round bottom flask under nitrogen atmosphere, then the solution was heated and refluxed with stirring for 12 hours. An organic layer was extracted with chloroform and washed with water. Water was removed with anhydrous MgSO4, the organic layer was filtered, the organic solvent was distilled under reduced pressure to be removed, and then a crude product was purified with column chromatography to give the Intermediate A-1 (6.05 g, yield: 95%).

(2) Synthesis of Intermediate I-1

Compound SM-3 (3.10 g, 20 mmol), IrCl3(2.39 g, 8.0 mmol) and a mixed solvent of ethoxyethanol (90 mL) and water (30 mL) were put into a 250 mL round bottom flask, and then the solution was stirred at 130° C. for 16 hours. After the reaction was complete, the solution was cooled to room temperature, methanol was added into the solution to filter the produced solid under reduced pressure and to give the Intermediate I-1 of solid (9.56 g, yield: 89%).

(3) Synthesis of Intermediate I-2

The Intermediate I-1 (5.16 g, 4.8 mmol), silver trifluoromethanesulfonate (AgOTf, 3.6 g, 14.3 mmol) and dichloromethane were put into a 1000 mL round bottom flask, and then the solution was stirred at room temperature for 16 hours. After the reaction was complete, the solution was filtered with celite to remove solid. The solvent was removed by distillation under reduced pressure to give the Intermediate I-2 of solid (6.03 g, yield: 88%).

(4) Synthesis of Compound 1

The Intermediate A-1 (1.11 g, 3.5 mmol), the Intermediate I-2 (2.15 g, 3.0 mmol) and a mixed solvent of 2-ethoxyethanol (40 mL) and DMF (40 mL) were put into a 100 mL round bottom flask under nitrogen atmosphere, and then the solution was stirred at 130° C. for 48 hours. After the reaction was complete, the organic layer extracted with dichloromethane and distilled water and the solvent was removed by distillation under reduced pressure. A crude product was purified with column chromatography (eluent: toluene and hexane) to give the Compound 1 (2.01 g, yield: 82%).

SYNTHESIS EXAMPLE 2

Synthesis of Compound 2

(1) Synthesis of Intermediate B-1

(2) Synthesis of Compound 2

The Intermediate B-1 (1.16 g, 3.5 mmol), the Intermediate I-2 (2.15 g, 3.0 mmol) and a mixed solvent of 2-ethoxyethanol (40 mL) and DMF (40 mL) were put into a 100 mL round bottom flask under nitrogen atmosphere, and then the solution was stirred at 130° C. for 48 hours. After the reaction was complete, the organic layer extracted with dichloromethane and distilled water and the solvent was removed by distillation under reduced pressure. A crude product was purified with column chromatography (eluent: toluene and hexane) to give the Compound 2 (2.02 g, yield: 81%).

SYNTHESIS EXAMPLE 3

Synthesis of Compound 16

(1) Synthesis of Intermediate C-1

(2) Synthesis of Compound 16

The Intermediate C-1 (1.12 g, 3.5 mmol), the Intermediate I-2 (2.15 g, 3.0 mmol) and a mixed solvent of 2-ethoxyethanol (40 mL) and DMF (40 mL) were put into a 100 mL round bottom flask under nitrogen atmosphere, and then the solution was stirred at 130° C. for 48 hours. After the reaction was complete, the organic layer extracted with dichloromethane and distilled water and the solvent was removed by distillation under reduced pressure. A crude product was purified with column chromatography (eluent: toluene and hexane) to give the Compound 16 (2.02 g, yield: 81%).

SYNTHESIS EXAMPLE 4

Synthesis of Compound 17

(1) Synthesis of Intermediate D-1

(2) Synthesis of Compound 17

The Intermediate D-1 (1.17 g, 3.5 mmol), the Intermediate I-2 (2.15 g, 3.0 mmol) and a mixed solvent of 2-ethoxyethanol (40 mL) and DMF (40 mL) were put into a 100 mL round bottom flask under nitrogen atmosphere, and then the solution was stirred at 130° C. for 48 hours. After the reaction was complete, the organic layer extracted with dichloromethane and distilled water and the solvent was removed by distillation under reduced pressure. A crude product was purified with column chromatography (eluent: toluene and hexane) to give the Compound 17 (2.25 g, yield: 90%).

SYNTHESIS EXAMPLE 5

Synthesis of Compound 27

(1) Synthesis of Intermediate E-1

(2) Synthesis of Compound 27

The Intermediate E-1 (1.43 g, 3.5 mmol), the Intermediate I-2 (2.15 g, 3.0 mmol) and a mixed solvent of 2-ethoxyethanol (40 mL) and DMF (40 mL) were put into a 100 mL round bottom flask under nitrogen atmosphere, and then the solution was stirred at 130° C. for 48 hours. After the reaction was complete, the organic layer extracted with dichloromethane and distilled water and the solvent was removed by distillation under reduced pressure. A crude product was purified with column chromatography (eluent: toluene and hexane) to give the Compound 27 (2.45 g, yield: 90%).

SYNTHESIS EXAMPLE 6

Synthesis of Compound 32

(1) Synthesis of Intermediate F-1

(2) Synthesis of Intermediate J-1

Compound SM-8 (3.38 g, 20 mmol), IrCl3(2.39 g, 8.0 mmol) and a mixed solvent of ethoxyethanol (90 mL) and water (30 mL) were put into a 250 mL round bottom flask, and then the solution was stirred at 130° C. for 16 hours. After the reaction was complete, the solution was cooled to room temperature, methanol was added into the solution to filter the produced solid under reduced pressure and to give the Intermediate J-1 of solid (4.07 g, yield: 90%).

(3) Synthesis of Intermediate J-2

The Intermediate J-1 (5.16 g, 4.8 mmol), silver trifluoromethanesulfonate (AgOTf, 3.6 g, 14.3 mmol) and dichloromethane were put into a 1000 mL round bottom flask, and then the solution was stirred at room temperature for 16 hours. After the reaction was complete, the solution was filtered with celite to remove solid. The solvent was removed by distillation under reduced pressure to give the Intermediate J-2 of solid (6.03 g, yield: 88%).

(4) Synthesis of Compound 32

The Intermediate F-1 (1.46 g, 3.5 mmol), the Intermediate J-2 (2.23 g, 3.0 mmol) and a mixed solvent of 2-ethoxyethanol (40 mL) and DMF (40 mL) were put into a 100 mL round bottom flask under nitrogen atmosphere, and then the solution was stirred at 130° C. for 48 hours. After the reaction was complete, the organic layer extracted with dichloromethane and distilled water and the solvent was removed by distillation under reduced pressure. A crude product was purified with column chromatography (eluent: toluene and hexane) to give the Compound 32 (2.47 g, yield: 87%).

SYNTHESIS EXAMPLE 7

Synthesis of Compound 34

(1) Synthesis of Intermediate G-1

(2) Synthesis of Compound 34

The Intermediate G-1 (1.45 g, 3.5 mmol), the Intermediate J-2 (2.23 g, 3.0 mmol) and a mixed solvent of 2-ethoxyethanol (40 mL) and DMF (40 mL) were put into a 100 mL round bottom flask under nitrogen atmosphere, and then the solution was stirred at 130° C. for 48 hours. After the reaction was complete, the organic layer extracted with dichloromethane and distilled water and the solvent was removed by distillation under reduced pressure. A crude product was purified with column chromatography (eluent: toluene and hexane) to give the Compound 34 (2.26 g, yield: 80%).

SYNTHESIS EXAMPLE 8

Synthesis of Compound 35

(1) Synthesis of Intermediate H-1

(2) Synthesis of Compound 35

The Intermediate H-1 (1.44 g, 3.5 mmol), the Intermediate J-2 (2.23 g, 3.0 mmol) and a mixed solvent of 2-ethoxyethanol (40 mL) and DMF (40 mL) were put into a 100 mL round bottom flask under nitrogen atmosphere, and then the solution was stirred at 130° C. for 48 hours. After the reaction was complete, the organic layer extracted with dichloromethane and distilled water and the solvent was removed by distillation under reduced pressure. A crude product was purified with column chromatography (eluent: toluene and hexane) to give the Compound 35 (2.28 g, yield: 81%).

SYNTHESIS EXAMPLE 9

Synthesis of Compound 136

(1) Synthesis of Intermediate A-2

The Intermediate A-1 (6.36 g, 20 mmol), IrCl3(2.39 g, 8.0 mmol) and a mixed solvent of ethoxyethanol (90 mL) and water (30 mL) were put into a 250 mL round bottom flask, and then the solution was stirred at 130° C. for 16 hours. After the reaction was complete, the solution was cooled to room temperature, methanol was added into the solution to filter the produced solid under reduced pressure and to give the Intermediate A-2 of solid (5.53 g, yield: 80%).

(2) Synthesis of Intermediate A-3

The Intermediate A-2 (8.29 g, 4.8 mmol), silver trifluoromethanesulfonate (AgOTf, 3.6 g, 14.3 mmol) and dichloromethane were put into a 1000 mL round bottom flask, and then the solution was stirred at room temperature for 16 hours. After the reaction was complete, the solution was filtered with celite to remove solid. The solvent was removed by distillation under reduced pressure to give the Intermediate A-3 of solid (7.99 g, yield: 80%).

(3) Synthesis of Compound 136

Compound L-1 (0.54 g, 3.5 mmol), the Intermediate A-3 (3.12 g, 3.0 mmol) and a mixed solvent of 2-ethoxyethanol (40 mL) and DMF (40 mL) were put into a 100 mL round bottom flask under nitrogen atmosphere, and then the solution was stirred at 130° C. for 48 hours. After the reaction was complete, the organic layer extracted with dichloromethane and distilled water and the solvent was removed by distillation under reduced pressure. A crude product was purified with column chromatography (eluent: toluene and hexane) to give the Compound 136 (2.46 g, yield: 80%).

SYNTHESIS EXAMPLE 10

Synthesis of Compound 137

Compound L-2 (0.35 g, 3.5 mmol), the Intermediate A-3 (3.12 g, 3.0 mmol) and a mixed solvent of 2-ethoxyethanol (40 mL) and DMF (40 mL) were put into a 100 mL round bottom flask under nitrogen atmosphere, and then the solution was stirred at 130° C. for 48 hours. After the reaction was complete, the organic layer extracted with dichloromethane and distilled water and the solvent was removed by distillation under reduced pressure. A crude product was purified with column chromatography (eluent: toluene and hexane) to give the Compound 137 (2.22 g, yield: 80%).

SYNTHESIS EXAMPLE 11

Synthesis of Compound 141

(1) Synthesis of Intermediate C-2

The Intermediate C-1 (6.36 g, 20 mmol), IrCl3(2.39 g, 8.0 mmol) and a mixed solvent of ethoxyethanol (90 mL) and water (30 mL) were put into a 250 mL round bottom flask, and then the solution was stirred at 130° C. for 16 hours. After the reaction was complete, the solution was cooled to room temperature, methanol was added into the solution to filter the produced solid under reduced pressure and to give the Intermediate C-2 of solid (5.32 g, yield: 77%).

(2) Synthesis of Intermediate C-3

The Intermediate C-2 (8.29 g, 4.8 mmol), silver trifluoromethanesulfonate (AgOTf, 3.6 g, 14.3 mmol) and dichloromethane were put into a 1000 mL round bottom flask, and then the solution was stirred at room temperature for 16 hours. After the reaction was complete, the solution was filtered with celite to remove solid. The solvent was removed by distillation under reduced pressure to give the Intermediate C-3 of solid (7.29 g, yield: 72%).

(3) Synthesis of Compound 141

Compound L-1 (0.54 g, 3.5 mmol), the Intermediate C-3 (3.13 g, 3.0 mmol) and a mixed solvent of 2-ethoxyethanol (40 mL) and DMF (40 mL) were put into a 100 mL round bottom flask under nitrogen atmosphere, and then the solution was stirred at 130° C. for 48 hours. After the reaction was complete, the organic layer extracted with dichloromethane and distilled water and the solvent was removed by distillation under reduced pressure. A crude product was purified with column chromatography (eluent: toluene and hexane) to give the Compound 141 (2.45 g, yield: 83%).

SYNTHESIS EXAMPLE 12

Synthesis of Compound 142

(1) Synthesis of Intermediate D-2

The Intermediate D-1 (6.64 g, 20 mmol), IrCl3(2.39 g, 8.0 mmol) and a mixed solvent of ethoxyethanol (90 mL) and water (30 mL) were put into a 250 mL round bottom flask, and then the solution was stirred at 130° C. for 16 hours. After the reaction was complete, the solution was cooled to room temperature, methanol was added into the solution to filter the produced solid under reduced pressure and to give the Intermediate D-2 of solid (5.71 g, yield: 80%).

(2) Synthesis of Intermediate D-3

The Intermediate D-2 (8.58 g, 4.8 mmol), silver trifluoromethanesulfonate (AgOTf, 3.6 g, 14.3 mmol) and dichloromethane were put into a 1000 mL round bottom flask, and then the solution was stirred at room temperature for 16 hours. After the reaction was complete, the solution was filtered with celite to remove solid. The solvent was removed by distillation under reduced pressure to give the Intermediate D-3 of solid (7.09 g, yield: 69%).

(3) Synthesis of Compound 142

Compound L-2 (0.35 g, 3.5 mmol), the Intermediate D-3 (3.21 g, 3.0 mmol) and a mixed solvent of 2-ethoxyethanol (40 mL) and DMF (40 mL) were put into a 100 mL round bottom flask under nitrogen atmosphere, and then the solution was stirred at 130° C. for 48 hours. After the reaction was complete, the organic layer extracted with dichloromethane and distilled water and the solvent was removed by distillation under reduced pressure. A crude product was purified with column chromatography (eluent: toluene and hexane) to give the Compound 142 (2.12 g, yield: 74%).

SYNTHESIS EXAMPLE 13

Synthesis of Compound 147

(1) Synthesis of Intermediate E-2

The Intermediate E-1 (8.16 g, 20 mmol), IrCl3(2.39 g, 8.0 mmol) and a mixed solvent of ethoxyethanol (90 mL) and water (30 mL) were put into a 250 mL round bottom flask, and then the solution was stirred at 130° C. for 16 hours. After the reaction was complete, the solution was cooled to room temperature, methanol was added into the solution to filter the produced solid under reduced pressure and to give the Intermediate E-2 of solid (7.26 g, yield: 87%).

(2) Synthesis of Intermediate E-3

The Intermediate E-2 (10.0 g, 4.8 mmol), silver trifluoromethanesulfonate (AgOTf, 3.6 g, 14.3 mmol) and dichloromethane were put into a 1000 mL round bottom flask, and then the solution was stirred at room temperature for 16 hours. After the reaction was complete, the solution was filtered with celite to remove solid. The solvent was removed by distillation under reduced pressure to give the Intermediate E-3 of solid (8.91 g, yield: 76%).

(3) Synthesis of Compound 147

Compound L-2 (0.35 g, 3.5 mmol), the Intermediate E-3 (3.36 g, 3.0 mmol) and a mixed solvent of 2-ethoxyethanol (40 mL) and DMF (40 mL) were put into a 100 mL round bottom flask under nitrogen atmosphere, and then the solution was stirred at 130° C. for 48 hours. After the reaction was complete, the organic layer extracted with dichloromethane and distilled water and the solvent was removed by distillation under reduced pressure. A crude product was purified with column chromatography (eluent: toluene and hexane) to give the Compound 147 (2.59 g, yield: 78%).

SYNTHESIS EXAMPLE 14

Synthesis of Compound 148

Compound L-1 (0.54 g, 3.5 mmol), the Intermediate E-3 (3.36 g, 3.0 mmol) and a mixed solvent of 2-ethoxyethanol (40 mL) and DMF (40 mL) were put into a 100 mL round bottom flask under nitrogen atmosphere, and then the solution was stirred at 130° C. for 48 hours. After the reaction was complete, the organic layer extracted with dichloromethane and distilled water and the solvent was removed by distillation under reduced pressure. A crude product was purified with column chromatography (eluent: toluene and hexane) to give the Compound 148 (2.96 g, yield: 85%).

Fabrication of OLED

An organic light emitting diode was fabricated applying Compound 1 obtained in Synthesis Example 1 as dopant into an emitting material layer (EML). A glass substrate onto which ITO (100 nm) was coated as a thin film was washed and ultrasonically cleaned by solvent such as isopropyl alcohol, acetone and dried at 100° C. oven. The substrate was transferred to a vacuum chamber for depositing emissive layer. Subsequently, an emissive layer and a cathode were deposited by evaporation from a heating boat under about 5-7 10−7Torr with setting deposition rate of 1 Å/s as the following order:

And then, capping layer (CPL) was deposited over the cathode and the device was encapsulated by glass. After deposition of emissive layer and the cathode, the OLED was transferred from the deposition chamber to a dry box for film formation, followed by encapsulation using UV-curable epoxy and moisture getter. The HIL material (HI-1), the HTL material (NPB), the Host in the EML and the ETL material (CBP and ET-1, respectively)are Illustrated in the following:

Fabrication of OLEDs

An OLED was fabricated using the same procedure and the same material as in Example 1, except that Compound 2 (Ex. 2), Compound 16 (Ex. 3), Compound 17 (Ex. 4), Compound 27 (Ex. 5), Compound 32 (Ex. 6), Compound 34 (Ex. 7) and Compound 35 (Ex. 8), respectively, were used as the dopant in the EML instead of Compound 1.

Fabrication of OLEDs

An OLED was fabricated using the same procedure and the same material as in Example 1, except that the following Ref-1 (Ref. 1), Ref-2 (Ref. 2), Ref-3 (Ref 3), Ref-4 (Ref 4), Ref-5 (Ref. 5), Ref-6 (Ref. 6) and Ref. 7 (Ref. 7), respectively, were used as the dopant in the EML instead of Compound 1.

EXPERIMENTAL EXAMPLE 1

Measurement of Luminous Properties of OLEDs

Each of the OLEDs, having 9 mm2of emission area, fabricated in Examples 1 to 8 and Comparative Examples 1-7 was connected to an external power source and then luminous properties for all the OLEDs were evaluated using a constant current source (KEITHLEY) and a photometer PR650at room temperature. In particular, driving voltage (V), maximum External quantum efficiency (EQEmax, relative value), External quantum efficiency (EQE, relative value) and time period (T95, relative value) at which the luminance was reduced to 95% from initial luminance was measured at a current density 10 mA/cm2. The measurement results are indicated in the following Table 1.

As indicated in Table 1, the OLED fabricated in Comparative Examples, the OLED into which the organic metal compound in accordance with the present disclosure as the dopant showed identical or a little bit reduced driving voltage, and improved its EQEmax, EQE and T95significantly.

Fabrication of OLEDs

An OLED was fabricated using the same procedure and the same material as in Example 1, except that Compound 136 (Ex. 9), Compound 137 (Ex. 10), Compound 141 (Ex. 11), Compound 142 (Ex. 12), Compound 147 (Ex. 13) and Compound 148 (Ex. 14), respectively, were used as the dopant in the EML instead of Compound 1.

Fabrication of OLEDs

An OLED was fabricated using the same procedure and the same material as in Example 1, except that the following Ref-8 (Ref. 8), Ref-9 (Ref 9), Ref-10 (Ref. 10) and Ref 11 (Ref. 11), respectively, were used as the dopant in the EML instead of Compound 1.

EXPERIMENTAL EXAMPLE 2

Measurement of Luminous Properties of OLEDs

Luminous properties for each of the OLEDs fabricated in Examples 9 to 12 and Comparative Examples 8-11 were measured using the same procedure as Experimental Example 1. The measurement results are indicated in the following Table 2.

As indicated in Table 2, the OLED fabricated in Comparative Examples, the OLED into which the organic metal compound in accordance with the present disclosure as the dopant showed identical or a little bit reduced driving voltage, and improved its EQEmax, EQE and T95significantly.

Taking the results in Tables 1 and 2 into account, it is possible to realize an OLED with lower driving voltage as well as excellent luminous efficiency and luminous lifespan by introducing the organic metal compound into an emissive layer.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope of the invention. Thus, it is intended that the present disclosure cover the modifications and variations of the present disclosure provided they come within the scope of the appended claims.