Organic electroluminescent device and organometallic compound for organic electroluminescent device

Abstract

To provide an organic electroluminescence device with high efficiency, low driving voltage, high luminance and a long life, and an organometallic compound used therefor.SOLUTION: For example, the organometallic compound is represented by formula 1-148.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an organic electroluminescent device and an organometallic compound used therein. [Background technology]

[0002] As a video display device, organic electroluminescence displays have been actively developed. Organic electroluminescence displays are so-called self-luminous display devices that emit light from a light-emitting material, which is an organic compound contained in a light-emitting layer, by recombining holes and electrons injected from a first electrode and a second electrode in the light-emitting layer.

[0003] Known organic electroluminescent devices include, for example, an organic electroluminescent device that includes a first electrode, a hole transport layer disposed on the first electrode, a light-emitting layer disposed on the hole transport layer, an electron transport layer disposed on the light-emitting layer, and a second electrode disposed on the electron transport layer. Holes are injected from the first electrode, and the injected holes move through the hole transport layer and are injected into the light-emitting layer. Meanwhile, electrons are injected from the second electrode, and the injected electrons move through the hole transport layer and are injected into the light-emitting layer. The holes and electrons injected into the light-emitting layer are recombined to generate excitons in the light-emitting layer. The organic electroluminescent device emits light by utilizing the light generated when the excitons fall further to the bottom state.

[0004] In order to apply organic electroluminescent devices to display devices, it is necessary to extend the life of the organic electroluminescent devices, and there is a continuous demand for development of materials for organic electroluminescent devices that can stably achieve this. Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide an organic electroluminescent device having high efficiency, low driving voltage, high luminance and long life, and an organometallic compound used therein. [Means for solving the problem]

[0006] An organic electroluminescent device according to one embodiment of the present invention includes a first electrode EL, a hole transport region, a light emitting layer, an electron transport region, and a second electrode EL2. The hole transport region is disposed on the first electrode. The light emitting layer is disposed on the hole transport region. The electron transport region is disposed on the light emitting layer. The second electrode is disposed on the electron transport region. The light emitting layer includes an organometallic compound. The organometallic compound includes a metal atom and four ligands each bonded to the metal atom. At least one of the four ligands is a group derived from a substituted or unsubstituted mesoionic carbene having 1 to 20 ring carbon atoms.

[0007] The four ligands may each independently be a group derived from a substituted or unsubstituted mesoionic carbene having from 1 to 20 ring carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms.

[0008] The four ligands may be tetradentate ligands each bonded to at least one of the adjacent ligands via a linking group.

[0009] The metal atom may be a platinum (Pt) atom.

[0010] The group derived from the mesoionic carbene may be derived to at least one selected from a substituted or unsubstituted imidazole precursor, a substituted or unsubstituted triazole precursor, a substituted or unsubstituted tetrazole precursor, a substituted or unsubstituted pyridine precursor, and a substituted or unsubstituted pyrazoline precursor. The light-emitting layer includes a host and a dopant. The dopant may include the organometallic compound.

[0011] The light-emitting layer may emit green light having a central wavelength of 500 nm or more and 600 nm or less. The light-emitting layer may emit the green light phosphorescence.

[0012] The organometallic compound is represented by the following Chemical Formula 1. [ka] ...(chemical formula 1)

[0013] In the above Chemical Formula 1, A1 to A4 are each independently a group derived from a substituted or unsubstituted mesoionic carbene having 1 to 20 ring carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms. At least one of A1 to A4 is a group derived from a mesoionic carbene. X 1 and X 4 R is independently a carbon atom or a nitrogen atom. 1 ~R 4 are each independently a hydrogen atom, a deuterium atom, a cyano group, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms, and may be bonded to adjacent groups to form a ring. a1 to a4 are each independently an integer of from 0 to 4.

[0014] L 1 ~L 4 each independently represents a single bond, [ka] R is a substituted or unsubstituted divalent alkylene group having from 1 to 20 ring carbon atoms, a substituted or unsubstituted arylene group having from 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroarylene group having from 2 to 30 ring carbon atoms. 5 and R 8are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, which may be bonded to adjacent groups to form a ring. m1 to m4 are each independently 0 or 1. T 1 ~T 4 are each independently a single bond, an oxygen atom, or a sulfur atom. M is platinum (Pt), palladium (Pd), copper (Cu), silver (Ag), gold (Au), rhodium (Rh), iridium (Ir), ruthenium (Ru), osmium (Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), or thorium (Tm).

[0015] The above-mentioned Chemical Formula 1 may be represented by the following Chemical Formula 2. [ka] ...(chemical formula 2)

[0016] In the above Chemical Formula 2, A1 to A4, X 1 ~X 4 , R 1 ~R 4 , a1 to a4, and L 2 is as defined in Chemical Formula 1 above.

[0017] At least one of A1 to A4 is a group derived from a mesoionic carbene represented by any one of the following chemical formulas 1-1 to 1-6. [ka]

[0018] JPEG0007617726000005.jpg95164

[0019] R 11 ~R 15are each independently a hydrogen atom, a deuterium atom, a cyano group, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms, and adjacent groups may be bonded to each other to form a ring. 21 ~R 26 are each independently a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms. a11 to a13 are each independently an integer of from 0 to 2.

[0020] The above formula 1-6 may be represented by the following formula 1-6-1. [ka] In the above formula 1-6-1, Y 3 , Y 4 , R 15 , R 26 and a14 are as defined in Chemical Formula 1-6 above.

[0021] At least one of A1 and A4 is represented by any one of Chemical Formulae 1-1 to 1-6, and the ligands of A1 and A4 that are not represented by Chemical Formulae 1-1 to 1-6, and A2 and A3 may each independently be represented by any one of Chemical Formulae 2-1 to 2-4 below. [ka]

[0022] JPEG0007617726000008.jpg78164

[0023] The above-mentioned Chemical Formula 1 may be represented by the following Chemical Formulas 3-1 to 3-7. [ka] ...(Chemical formula 3-1) [ka] ...(chemical formula 3-2) [ka] ...(Chemical formula 3-3) [ka] ...(chemical formula 3-4) [ka] ...(chemical formula 3-5) [ka] ...(chemical formula 3-6) [ka] ...(Chemical formula 3-7)

[0024] In the chemical formulas 3-1 and 3-2, A1 is represented by any one of the chemical formulas 1-1 to 1-5. In the chemical formulas 3-3 and 3-5, at least one of A1 and A4 is represented by any one of the chemical formulas 1-1 to 1-5. In the chemical formulas 3-4, at least one of A1 and A3 is represented by any one of the chemical formulas 1-1 to 1-5. In the chemical formulas 3-6 and 3-7, A1 is represented by the chemical formula 1-6.

[0025] In the above Chemical Formulae 3-1 to 3-6, R 51 ~R 64are each independently a hydrogen atom, a deuterium atom, a cyano group, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms, and may be bonded to adjacent groups to form a ring. Z is a carbon atom or a nitrogen atom. a21, a23, a24, a26, a27, a29, a30, a32, a33, and a34 are each independently an integer of from 0 to 3. a22, a28, and a31 are each independently an integer of from 0 to 4. a25 is an integer of from 0 to 2. Y 13 ~Y 19 , and L 2 is as defined in Chemical Formula 2-2 above.

[0026] The light-emitting layer contains at least one of the compounds shown in the following first compound group and second compound group. [First compound group] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka]

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

[0027] According to one embodiment of the present invention, the organometallic compound described above can be provided. Effect of the Invention

[0028] The organic electroluminescent device according to an embodiment of the present invention can achieve high efficiency, low driving voltage, high brightness, and long life.

[0029] The organometallic compound according to an embodiment of the present invention can be used in an organic electroluminescent device to achieve high efficiency, low driving voltage, high brightness, and long life. [Brief description of the drawings]

[0030] [Figure 1] 1 is a cross-sectional view illustrating an organic electroluminescent device according to an embodiment of the present invention. [Diagram 2] 1 is a cross-sectional view illustrating an organic electroluminescent device according to an embodiment of the present invention. [Diagram 3] 1 is a cross-sectional view illustrating an organic electroluminescent device according to an embodiment of the present invention. [Figure 4] FIG. 1 is a diagram for explaining the structure of a mesoionic carbene. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Since the present invention can be modified in various ways and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text, but it should be understood that the present invention is not limited to the specific disclosed form, but includes all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0032] In the drawings, like reference numerals are used for like elements. In the accompanying drawings, the dimensions of structures are exaggerated for clarity of the present invention. Terms such as first and second are used to describe various elements, but the elements are not limited to the terms. The terms are used only to distinguish one structural element from another. For example, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element, without departing from the scope of the present invention. A singular expression includes a plural expression unless the context clearly indicates otherwise.

[0033] In this application, the terms "comprise" or "have" and the like are intended to mean the presence of any feature, numeral, step, operation, component, part, or combination thereof described hereinabove in the specification, but are to be understood as not precluding the presence or additional possibility of one or more other features, numerals, steps, operations, components, parts, or combinations thereof.

[0034] In this application, when a layer, film, region, plate, or other part is described as being "on" or "above" another part, this includes not only when it is "directly above" the other part, but also when there is another part in between. Conversely, when a layer, film, region, plate, or other part is described as being "below" or "below" another part, this includes not only when it is "directly below" the other part, but also when there is another part in between. Also, in this application, being "located on" includes not only when it is located at the top, but also when it is located at the bottom.

[0035] In this specification, "substituted or unsubstituted" means that the group is substituted or unsubstituted with one or more substituents selected from the group consisting of a deuterium atom, a halogen atom, a cyano group, a nitro group, an amino group, a silyl group, an oxy group, a thio group, a sulfinyl group, a sulfonyl group, a carbonyl group, a boryl group, a phosphine oxide group, a phosphine sulfide group, an alkyl group, an alkenyl group, an alkoxy group, a hydrocarbon ring group, an aryl group, and a heterocyclic group. In addition, each of the substituents exemplified above may be substituted or unsubstituted. For example, a biphenylyl group may be interpreted as an aryl group, or as a phenyl group substituted with a phenyl group.

[0036] In this specification, "adjacent groups bond together to form a ring" means adjacent groups bond together to form a substituted or unsubstituted hydrocarbon ring, or a substituted or unsubstituted hetero ring. The hydrocarbon ring includes an aliphatic hydrocarbon ring and an aromatic hydrocarbon ring. The hetero ring includes an aliphatic hetero ring and an aromatic hetero ring. The hydrocarbon ring and the hetero ring are monocyclic and polycyclic. In addition, the ring formed by bonding together may be bonded to another ring to form a spiro structure.

[0037] In this specification, the term "adjacent groups" refers to a substituent substituted on an atom directly bonded to the atom on which the substituent is substituted, another substituent substituted on an atom on which the substituent is substituted, or a substituent that is structurally most adjacent to the substituent. For example, two methyl groups in 1,2-dimethylbenzene are interpreted as "adjacent groups" to each other, and two ethyl groups in 1,1-diethylcyclopentene are interpreted as "adjacent groups" to each other.

[0038] In this specification, examples of halogen atoms include a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

[0039] In this specification, an alkyl group is linear, branched, or cyclic. The number of carbon atoms in an alkyl group is 1 to 50, 1 to 30, 1 to 20, 1 to 10, or 1 to 6. Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, t-butyl, i-butyl, 2-ethylbutyl, 3,3-dimethylbutyl, n-pentyl, i-pentyl, neopentyl, t-pentyl, cyclopentyl, 1-methylpentyl, 3-methylpentyl, 2-ethylpentyl, 4-methyl-2-pentyl, n-hexyl, 1-methylhexyl, 2-ethylbutyl ... Hexyl, 2-butylhexyl, cyclohexyl, 4-methylcyclohexyl, 4-t-butylcyclohexyl, n-heptyl, 1-methylheptyl, 2,2-dimethylheptyl, 2-ethylheptyl, 2-butylheptyl, n-octyl, t-octyl, 2-ethyloctyl, 2-butyloctyl, 2-hexyloctyl, 3,7-dimethyloctyl, cyclooctyl, n-nonyl, n-decyl, adamantyl n-butyldecyl, 2-ethyldecyl, 2-butyldecyl, 2-hexyldecyl, 2-octyldecyl, n-undecyl, n-dodecyl, 2-ethyldodecyl, 2-butyldodecyl, 2-hexyldodecyl, 2-octyldecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, 2-ethylhexadecyl, 2-butylhexadecyl, 2-hexylhexadecyl, 2-octylhexadecyl , n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n-icosyl group, 2-ethylicosyl group, 2-butylicosyl group, 2-hexylicosyl group, 2-octylicosyl group, n-henicosyl group, n-docosyl group, n-tricosyl group, n-tetracosyl group, n-pentacosyl group, n-hexacosyl group, n-heptacosyl group, n-octacosyl group, n-nonacosyl group, and n-triacontyl group, but are not limited to these.

[0040] In the present specification, the term "hydrocarbon ring group" refers to any functional group or substituent derived from an aliphatic hydrocarbon ring. The hydrocarbon ring group is a saturated hydrocarbon ring group having 5 to 20 ring carbon atoms.

[0041] In this specification, the aryl group means any functional group or substituent derived from an aromatic hydrocarbon ring. The aryl group is a monocyclic aryl group or a polycyclic aryl group. The number of ring carbon atoms of the aryl group is 6 to 30, 6 to 20, or 6 to 15. Examples of the aryl group include, but are not limited to, a phenyl group, a naphthyl group, a fluorenyl group, an anthracenyl group, a phenanthryl group, a biphenylyl group, a terphenylyl group, a quaterphenylyl group, a quinquephenylyl group, a sexiphenylyl group, a triphenylenyl group, a pyrenyl group, a benzofluoranthenyl group, and a chrysenyl group.

[0042] In this specification, the heteroaryl group includes one or more of B, O, N, P, Si, and S as heteroatoms. If the heteroaryl group includes two or more heteroatoms, the two or more heteroatoms may be the same or different. The heteroaryl group is a monocyclic heterocyclic group or a polycyclic heterocyclic group. The number of ring carbon atoms of the heteroaryl group is 2 to 30, 2 to 20, or 2 to 10. Examples of the heteroaryl group include a thiophenyl group, a furanyl group, a pyrrolyl group, an imidazolyl group, a thiazolyl group, an oxazolyl group, an oxadiazolyl group, a triazolyl group, a pyridinyl group, a bipyridinyl group, a pyrimidinyl group, a triazinyl group, a triazolyl group, an acridinyl group, a pyridazinyl group, a pyrazinyl group, a quinolinyl group, a quinazolinyl group, a quinoxalinyl group, a phenoxanyl group, a phthalazinyl group, a pyridopyrimidinyl group, a pyridopyrazinyl group, a pyrazinopyrazinyl group, an isoquinolinyl group, an indolyl group, a carbazolyl group, an N-aryl group, Examples of the group include, but are not limited to, arylcarbazolyl group, N-heteroarylcarbazolyl group, N-alkylcarbazolyl group, benzoxazolyl group, benzimidazolyl group, benzothiazolyl group, benzocarbazolyl group, benzothiophenyl group, dibenzothiophenyl group, thienothiophenyl group, benzofuranyl group, phenanthrolinyl group, isoxazolyl group, oxadiazolyl group, thiadiazolyl group, phenothiazinyl group, dibenzosilolyl group, dibenzofuranyl group, and groups derived from aromatic heterocyclic carbene. The group derived from aromatic heterocyclic carbene may be a group derived from aromatic N-heterocyclic carbene. The group derived from N-heterocyclic carbene is, for example, a group derived from imidazol-2-ylidene.

[0043] In this specification, the above explanation of the aryl group applies to the arylene group, except that the arylene group is a divalent group. The above explanation of the heteroaryl group applies to the heteroarylene group, except that the heteroarylene group is a divalent group.

[0044] In this specification, the silyl group includes an alkylsilyl group and an arylsilyl group. Examples of the silyl group include, but are not limited to, a trimethylsilyl group, a triethylsilyl group, a t-butyldimethylsilyl group, a vinyldimethylsilyl group, a propyldimethylsilyl group, a triphenylsilyl group, a diphenylsilyl group, a phenylsilyl group, and the like.

[0045] In this specification, a thio group includes alkylthio groups and arylthio groups.

[0046] In this specification, the oxy group includes an alkoxy group and an aryloxy group. The alkoxy group may be linear, branched, or cyclic. The number of carbon atoms in the alkoxy group is not particularly limited, but may be, for example, 1 to 20 or 1 to 10. Examples of the oxy group include, but are not limited to, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, a nonyloxy group, a decyloxy group, and a benzyloxy group.

[0047] In this specification, the boryl group includes an alkylboryl group and an arylboryl group. Examples of the boryl group include, but are not limited to, a trimethylboryl group, a triethylboryl group, a t-butyldimethylboryl group, a triphenylboryl group, a diphenylboryl group, and a phenylboryl group.

[0048] In this specification, the alkenyl group is a straight chain or a branched chain. The number of carbon atoms is not particularly limited, but is 2 to 30, 2 to 20, or 2 to 10. Examples of the alkenyl group include, but are not limited to, a vinyl group, a 1-butenyl group, a 1-pentenyl group, a 1,3-butadienylaryl group, a styrenyl group, and a styrylvinyl group.

[0049] In this specification, the number of carbon atoms of the amino group is not particularly limited, but is from 1 to 30. The amino group includes an alkylamino group and an arylamino group. Examples of the amino group include, but are not limited to, a methylamino group, a dimethylamino group, a phenylamino group, a diphenylamino group, a naphthylamino group, a 9-methyl-anthracenylamino group, and a triphenylamino group.

[0050] In this specification, among the alkylthio group, alkylsulfoxy group, alkylaryl group, alkylamino group, alkylboryl group, and alkylsilyl group, the alkyl group is the same as the above-mentioned examples of the alkyl group.

[0051] In this specification, the aryl group among the aryloxy group, arylthio group, arylsulfoxy group, arylamino group, arylboryl group, and arylsilyl group is the same as the above-mentioned examples of the aryl group.

[0052] In this specification, a direct linkage may mean a single bond.

[0053] 1 is a schematic cross-sectional view of an organic electroluminescent device according to an embodiment of the present invention. The organic electroluminescent device 10 according to an embodiment of the present invention includes a first electrode EL1, a hole transport region HTR, an emission layer EML, an electron transport region ETR, and a second electrode EL2, which are sequentially stacked.

[0054] Fig. 2 is a cross-sectional view of an organic electroluminescent device 10 according to an embodiment, in which the hole transport region HTR includes a hole injection layer HIL and a hole transport layer HTL, and the electron transport region ETR includes an electron injection layer EIL and an electron transport layer ETL, unlike Fig. 1. Also, Fig. 3 is a cross-sectional view of an organic electroluminescent device 10 according to an embodiment, in which the hole transport region HTR includes a hole injection layer HIL, a hole transport layer HTL, and an electron blocking layer EBL, and the electron transport region ETR includes an electron injection layer EIL, an electron transport layer ETL, and a hole blocking layer HBL, unlike Fig. 1.

[0055] At least one of the hole transport region HTR, the light emitting layer EML, and the electron transport region ETR includes an organometallic compound according to an embodiment, which will be described in detail later.

[0056] The first electrode EL1 has conductivity. The first electrode EL1 is made of a metal or a conductive compound. The first electrode EL1 is an anode. Also, the first electrode EL1 is a pixel electrode. The first electrode EL1 is a transmissive electrode, a semi-transmissive electrode, or a reflective electrode. If the first electrode EL1 is a transmissive electrode, the first electrode EL1 includes a transparent metal oxide, for example, ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), ITZO (indium tin zinc oxide), etc. If the first electrode EL1 is a semi-transmissive electrode or a reflective electrode, the first electrode EL1 includes Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, or a compound or mixture thereof (for example, an alloy of Ag and Mg). The first electrode EL1 may have a multi-layer structure including a reflective film or semi-transparent film made of the above-mentioned material, and a transparent conductive film made of ITO, IZO, ZnO, ITZO, etc. For example, the first electrode EL1 may have a triple-layer structure of ITO / Ag / ITO, but is not limited thereto. The thickness of the first electrode EL1 may be about 100 nm to about 1000 nm, for example, about 100 nm to about 300 nm.

[0057] The hole transport region HTR is disposed on the first electrode EL1 and includes at least one of a hole injection layer HIL, a hole transport layer HTL, a hole buffer layer (not shown), and an electron blocking layer EBL.

[0058] The hole transport region HTR may have a single layer of a single material, a single layer of a plurality of different materials, or a multi-layer structure having a plurality of layers of a plurality of different materials.

[0059] For example, the hole transport region HTR may have a single layer structure of a hole injection layer HIL or a hole transport layer HTL, or a single layer structure of a hole injection material and a hole transport material. The hole transport region HTR may have a single layer structure of a plurality of different materials, or a structure of a hole injection layer HIL / hole transport layer HTL, a hole injection layer HIL / hole transport layer HTL / hole buffer layer (not shown), a hole injection layer HIL / hole buffer layer (not shown), a hole transport layer HTL / hole buffer layer, or a hole injection layer HIL / hole transport layer HTL / electron blocking layer EBL, which are stacked in order from the first electrode EL1, but the embodiments of the present disclosure are not limited thereto.

[0060] The hole transport region HTR can be formed using various methods such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) method, inkjet printing, laser printing, and Laser Induced Thermal Imaging (LITI).

[0061] The hole injection layer HTL may be formed by mixing, for example, a phthalocyanine compound such as copper phthalocyanine with a phthalocyanine compound such as DNTPD (N,N'-diphenyl-N,N'-bis-[4-phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4'-diamine), m-MTDATA (4,4',4"-tris(3-methylphenylphenylamino)triphenylamine), TDATA (4,4',4"-tris(N,N-diphenylamino)triphenylamine), 2-TNATA (4,4',4"-tris{N,-(2-naphthyl)-N-phenylamino}-triphenylamine), PEDOT / PSS (poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonyl)). sulfonate), PANI / DBSA (polyaniline / dodecylbenzenesulfonic acid), PANI / CSA (polyaniline / camphorsulfonic acid), PANI / PSS (polyaniline) / poly(4-styrenesulfonate), NPB (N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine), triphenylamine-containing polyether ketone (TPAPEK), 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate, and HAT-CN (dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile).

[0062] The hole transport layer HTL may include, for example, a carbazole derivative such as N-phenylcarbazole or polyvinylcarbazole, a fluorene derivative, a triphenylamine derivative such as TPD (N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1-biphenyl]-4,4'-diamine) or TCTA (tris(4-carbazolyl-9-ylphenyl)amine), NPB (N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine), TAPC (4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzeneamine]), HMTPD (4,4'-bis[N,N'-(3-tolyl)amino]-3,3'-dimethylbiphenyl), or mCP (1,3-bis(N-carbazolyl)benzene).

[0063] The thickness of the hole transport region HTR may be about 10 nm to about 1000 nm, for example, about 10 nm to about 500 nm. The thickness of the hole injection layer HIL may be, for example, about 3 nm to about 100 nm, and the thickness of the hole transport layer HTL may be about 3 nm to about 100 nm. For example, the thickness of the electron blocking layer EBL may be about 1 nm to about 100 nm. When the thicknesses of the hole transport region HTR, the hole injection layer HIL, the hole transport layer HTL, and the electron blocking layer EBL satisfy the above-mentioned ranges, sufficient hole transport properties can be obtained without a substantial increase in driving voltage.

[0064] In addition to the above-mentioned materials, the hole transport region HTR may further include a charge generating material to improve conductivity. The charge generating material is uniformly or non-uniformly dispersed in the hole transport region HTR. The charge generating material may be, for example, a p-dopant. The p-dopant may be one of, but is not limited to, a quinone derivative, a metal oxide, and a cyano group-containing compound. For example, examples of p-dopants include, but are not limited to, quinone derivatives such as TCNQ (tetracyanoquinodimethane) and F4-TCNQ (2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane), metal oxides such as tungsten oxide, and molybdenum oxide.

[0065] As described above, the hole transport region HTR may further include at least one of a hole buffer layer (not shown) and an electron blocking layer EBL in addition to the hole transport layer HTL and the hole injection layer HIL. The hole buffer layer (not shown) compensates for the resonance distance according to the wavelength of light emitted from the emission layer EML to increase light emission efficiency. The material contained in the hole buffer layer (not shown) may be a material that may be contained in the hole transport region HTR. The electron blocking layer EBL is a layer that serves to prevent the injection of electrons from the electron transport region ETR to the hole transport region HTR.

[0066] The light-emitting layer EML is disposed on the hole-transporting region HTR. The light-emitting layer EML has a thickness of, for example, about 10 nm to about 100 nm, or about 10 nm to about 30 nm. The light-emitting layer EML has a multilayer structure having a single layer made of a single material, a single layer made of a plurality of different materials, or a plurality of layers made of a plurality of different materials.

[0067] The light-emitting layer EML includes an organometallic compound according to one embodiment.

[0068] An organometallic compound according to an embodiment includes a metal atom and a ligand bonded to the metal atom. More specifically, the organometallic compound includes a metal atom and four ligands bonded to the metal atom. The metal atom and the ligands are bonded by a coordinate bond. At least one of the four ligands includes a group derived from a mesoionic carbene. The group derived from a mesoionic carbene is a group derived from a substituted or unsubstituted mesoionic carbene having 1 to 20 ring carbon atoms.

[0069] The metal atom may be platinum (Pt), palladium (Pd), copper (Cu), silver (Ag), gold (Au), rhodium (Rh), iridium (Ir), ruthenium (Ru), osmium (Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), or thorium (Tm). For example, the metal atom may be a platinum (Pt) atom.

[0070] The group derived from a mesoionic carbene is a group derived from an aromatic mesoionic carbene. The group derived from an aromatic mesoionic carbene is derived from a nitrogen-containing heterocycle. For example, the group derived from a mesoionic carbene may be a group derived from at least one selected from a substituted or unsubstituted imidazole precursor, a substituted or unsubstituted triazole precursor, a substituted or unsubstituted tetrazole precursor, a substituted or unsubstituted pyridine precursor, and a substituted or unsubstituted pyrazoline precursor. For example, the mesoionic carbene may be an imidazoline-4-ylidene derivative, a 1,2,3-triazole ylidene derivative, a tetrazole-5-ylidene derivative, a pyridin-3-ylidene derivative, a pyrazoline-5-ylidene derivative, an imidazo[1,2-a]pyridin-2-ylidene, or an imidazo[1,2-a]pyridin-3-ylidene derivative. More particularly, the mesoionic carbene may be a substituted or unsubstituted imidazoline-4-ylidene, a substituted or unsubstituted 1,2,3-triazolylidene, a substituted or unsubstituted tetrazol-5-ylidene, a substituted or unsubstituted pyridin-3-ylidene, a substituted or unsubstituted pyrazolin-5-ylidene, an imidazo[1,2-a]pyridin-2-ylidene, or an imidazo[1,2-a]pyridin-3-ylidene. The substituted pyrazolin-5-ylidene is a substituted benzopyrazoline-5-ylidene.

[0071] The four ligands are each independently a group derived from a mesoionic carbene, an aryl group, or a heteroaryl group, more specifically, a substituted or unsubstituted group derived from a mesoionic carbene having from 1 to 20 ring carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms.

[0072] The four ligands may be tetradentate ligands each bonded to at least one of the adjacent ligands via a linking group. That is, the four ligands may be one tetradentate ligand bonded to each other. For example, the first ligand and the second ligand may be bonded to each other via a linking group, the second ligand and the third ligand may be bonded to each other via a linking group, and the third ligand and the fourth ligand may be bonded to each other via a linking group. The linking group is a single bond or a divalent linking group.

[0073] The organometallic compound according to one embodiment is represented by Formula 1. [ka] ...(chemical formula 1)

[0074] In Chemical Formula 1, A1 to A4 represent four ligands. A1 to A4 are each independently a group derived from a mesoionic carbene, an aryl group, or a heteroaryl group. The group derived from a mesoionic carbene is a substituted or unsubstituted group derived from a mesoionic carbene having 1 to 20 ring carbon atoms. The aryl group is a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms. The heteroaryl group is a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms. At least one of A1 to A4 is a group derived from a mesoionic carbene.

[0075] The aryl group is, for example, a substituted or unsubstituted phenyl group. The heteroaryl group is a substituted or unsubstituted pyridinyl group, a substituted or unsubstituted carbazolyl group, or a group derived from a substituted or unsubstituted heterocyclic carbene. The group derived from a heterocyclic carbene is a group derived from a normal N-heterocyclic carbene. For example, the group derived from a heterocyclic carbene is a group derived from a substituted or unsubstituted imidazol-2-ylidene.

[0076] X 1 and X 4 are each independently a carbon atom or a nitrogen atom.

[0077] R 1 ~R 4 R are each independently a hydrogen atom, a deuterium atom, a cyano group, an alkyl group, an aryl group, or a heteroaryl group. 1 ~R 4 may bond with adjacent groups to form a ring. The alkyl group is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms. The aryl group is a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms. The heteroaryl group is a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms.

[0078] For example, the alkyl group is a methyl group or a t-butyl group. The aryl group is a substituted or unsubstituted phenyl group. R 1 ~R 4 may be bonded to an adjacent group to form a substituted or unsubstituted phenyl group, or a substituted or unsubstituted pyrazinyl group.

[0079] a1 to a4 are each independently an integer of 0 to 4. If a1 is an integer of 2 or more, a plurality of R 1 may be the same as or different from each other. Substantially the same explanation as for a1 is also applied to a2 to a4.

[0080] L 1 ~L 4 each independently represents a single bond, [ka] It is an alkylene, an arylene group, or a heteroarylene group. The alkylene group is a substituted or unsubstituted divalent alkylene group having 1 to 20 carbon atoms. The arylene group is a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms. The heteroarylene group is a substituted or unsubstituted heteroarylene group having 2 to 30 ring carbon atoms.

[0081] For example, L1 and L 3 is a single bond, L 2 teeth [ka] It may be any one of the above.

[0082] JPEG0007617726000113.jpg21164

[0083] R 5 ~R 8 are each independently a hydrogen atom, a deuterium atom, an alkyl group, an aryl group, or a heteroaryl group, and may be bonded to adjacent groups to form a ring. The alkyl group is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms. The aryl group is a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms. The heteroaryl group is a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms. For example, R 5 ~R 8 may be a methyl group or a substituted or unsubstituted phenyl group. For example, R 6 and R 7 may be bonded to each other to form a ring. 6 and R 7 may be linked together to form a dibenzosilyl group as shown below. [ka]

[0084] Each of m1 to m4 is independently 0 or 1. For example, m1 to m3 may be 1 and m4 may be 0.

[0085] T 1 ~T 4 are each independently a single bond, an oxygen atom, or a sulfur atom. For example, T 1 ~T 4 may each be a single bond.

[0086] M is platinum (Pt), palladium (Pd), copper (Cu), silver (Ag), gold (Au), rhodium (Rh), iridium (Ir), ruthenium (Ru), osmium (Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), or thorium (Tm). For example, M may be a platinum (Pt) atom, a palladium (Pd) atom, a rhodium (Rh) atom, or an osmium (Os) atom.

[0087] Chemical Formula 1 is represented by Chemical Formula 2 below. [ka] ...(chemical formula 2)

[0088] Chemical formula 2 is the same as formula 1 except that 1 , L 3 , L 4 , m1~m4, T 1~ T 4 In Chemical Formula 2, A1 to A4, X, and M are embodied. 1 ~X 4 , R 1 ~R 4 , a1 to a4, and L 2 is as defined in Chemical Formula 1 above.

[0089] At least one of A1 to A4 is a group derived from a mesoionic carbene represented by any one of the following chemical formulas 1-1 to 1-6. [ka]

[0090] JPEG0007617726000117.jpg129164

[0091] R 11 ~R 15are each independently a hydrogen atom, a deuterium atom, a cyano group, an alkyl group, an aryl group, or a heteroaryl group, and may be bonded to adjacent groups to form a ring. The alkyl group is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms. The aryl group is a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms. The heteroaryl group is a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms. In more detail, R 11 ~R 15 are each independently a hydrogen atom, an unsubstituted methyl group, an unsubstituted isopropyl group, an unsubstituted t-butyl group, or CD 3 R is a substituted or unsubstituted phenyl group. 11 ~R 15 When each of the groups bonded to the adjacent groups to form a ring, they may form a substituted or unsubstituted phenyl group.

[0092] a11 to a13 each independently represents an integer of 0 or more and 3 or less. a14 is an integer of 0 or more and 4 or less.

[0093] If a11 is an integer of 2 or more, multiple R 11 may be the same as or different from each other. The same explanation as for a11 is applied to a12 to a14.

[0094] R 21 ~R 26 are each independently an alkyl group, an aryl group, or a heteroaryl group. The alkyl group is a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms. The aryl group is a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms. The heteroaryl group is a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms. For example, R 21 ~R 26 may each independently be an unsubstituted methyl group, or a substituted or unsubstituted phenyl group.

[0095] For example, at least one or two of A1 to A4 may be a group derived from a mesoionic carbene represented by any one of chemical formulas 1-1 to 1-6. When A1 to A4 are all groups derived from a mesoionic carbene, A1 to A4 may be the same or different. More specifically, A1 to A4 are each independently a group derived from a mesoionic carbene represented by any one of chemical formulas 1-1 to 1-6, and any one of A1 to A4 is a group derived from a mesoionic carbene represented by any one of chemical formulas 1-1 to 1-6.

[0096] In one embodiment, chemical formula 1-5 is represented by the following chemical formula 1-5-1: [ka]

[0097] In Chemical Formula 1-5-1, R 14 and a13 is as defined in 1-5.

[0098] Chemical formula 1-6 is represented by the following chemical formula 1-6-1. [ka]

[0099] In the chemical formula 1-6-1, Y 3 , Y 4 , R 15 , R 26 and a14 are as defined in formula 1-6.

[0100] At least one of A1 and A4 is represented by any one of the above chemical formulas 1-1 to 1-6, and the ligands of A1 and A4 not represented by chemical formulas 1-1 and 1-6 may be represented by any one of the following chemical formulas 2-1 to 2-4. Also, A2 and A3 may each independently be represented by any one of the following chemical formulas 2-1 to 2-4. [ka]

[0101] JPEG0007617726000121.jpg142164

[0102] For example, Chemical Formula 1 is represented by the following Chemical Formulas 3-1 to 3-7. [ka] ...(Chemical formula 3-1) [ka] ...(chemical formula 3-2) [ka] ...(Chemical formula 3-3) [ka] ...(chemical formula 3-4) [ka] ...(chemical formula 3-5) [ka] ...(chemical formula 3-6) [ka] ...(Chemical formula 3-7)

[0103] In Chemical Formula 3-1 and Chemical Formula 3-2, A1 is represented by any one of the above Chemical Formulas 1-1 to 1-5.

[0104] In Chemical Formula 3-3 and Chemical Formula 3-5, at least one of A1 and A4 is represented by any one of Chemical Formulas 1-1 to 1-5.

[0105] In Chemical Formula 3-4, at least one of A1 and A3 is represented by any one of Chemical Formulas 1-1 to 1-5 above.

[0106] In Chemical Formula 3-6 and Chemical Formula 3-7, A1 is represented by the above Chemical Formula 1-6.

[0107] In Chemical Formula 3-1 and Chemical Formula 3-7, R 51 ~R 64 are each independently a hydrogen atom, a deuterium atom, a cyano group, an alkyl group, an aryl group, or a heteroaryl group, and may be bonded to adjacent groups to form a ring. The alkyl group is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms. The aryl group is a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms. The heteroaryl group is a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms.

[0108] Z is a carbon atom or a nitrogen atom.

[0109] a21, a23, a24, a26, a27, a29, a30, a32, a33, and a34 are each independently an integer of 0 to 3. a22, a28, and a31 are each independently an integer of 0 to 4. a25 is an integer of 0 to 2. Y 13 ~Y 19 , and L 2 is as defined in Chemical Formula 2-2 above.

[0110] R 51 If there are multiple, then there are multiple R 51 are the same or different from each other. This means that R 52 ~R 64 The same applies to .

[0111] If a25 is 2 or more, two R 55 may be bonded to each other to form a benzene ring.

[0112] In Chemical Formula 3-1 and Chemical Formula 3-3, A1 may be any one of Chemical Formulas 1-1 to 1-3 and Chemical Formula 1-5 described above.

[0113] In Chemical Formula 3-2, A1 may be any one of Chemical Formulas 1-1 to 1-5 described above.

[0114] In Chemical Formula 3-3, A4 may be any one of the above Chemical Formulas 1-1 to 1-3, A1 and A4 may be the same or different.

[0115] In formula 3-3, A1 may be the above-mentioned formula 1-5, and A4 may be the above-mentioned formula 2-1.

[0116] In Chemical Formula 3-4, A1 may be any one of Chemical Formulas 2-1 to 2-4 described above, and A3 may be any one of Chemical Formulas 1-4 described above. More specifically, A1 may be any one of Chemical Formulas 2-3 to 2-4 described above.

[0117] In Chemical Formula 3-5, A1 may be any one of Chemical Formulas 2-1 to 2-4, and A4 may be any one of Chemical Formulas 1-4. More specifically, A4 may be any one of Chemical Formulas 2-3 and 2-4.

[0118] In the formulae 3-6 and 3-7, A1 may be the formula 1-6 described above.

[0119] Chemical formula 3-6 may be represented by chemical formula 3-6-1 and chemical formula 3-6-2. [ka] ...(Chemical formula 3-6-1) [ka] ...(Chemical formula 3-6-2)

[0120] Chemical formula 3-6-1 and chemical formula 3-6-2 are chemical formulas in which A1 in chemical formula 3-6 is embodied. In chemical formula 3-6-1 and chemical formula 3-6-2, R 26 is as defined in Formula 1-6 above. 13 ~Y 19 , R 26 , R 60、 R 61 , a30, and a31 are as defined in Chemical Formula 3-6.

[0121] Chemical formula 3-7 may be represented by chemical formula 3-7-1 and chemical formula 3-7-2. [ka] ...(Chemical formula 3-7-1) [ka] ...(Chemical formula 3-7-2)

[0122] Chemical formula 3-7-1 and chemical formula 3-7-2 are chemical formulas in which A1 is embodied in chemical formula 3-7. 26 is as defined in formula 1-6. 26 , R 62 ~R 64、 a32 and a35 are as defined in formula 3-7.

[0123] The organometallic compound in one embodiment may be any one of the compounds shown in the first compound group and the second compound group below. [First compound group] [ka] [ka] [ka]

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

change

[0124] In the organic electroluminescent device 10 according to one embodiment shown in FIGS. 1 to 3, the emission layer EML contains a host and a dopant, and the emission layer EML contains the organometallic compound according to one embodiment as a dopant material.

[0125] The light-emitting layer EML emits green light by including the organometallic compound according to one embodiment as a dopant material. For example, the light-emitting layer EML emits phosphorescence to emit green light having a central wavelength of 500 nm or more and 600 nm or less.

[0126] In the organic electroluminescent device 10 according to an embodiment, the light-emitting layer EML may further include an anthracene derivative, a pyrene derivative, a fluoranthene derivative, a chrysene derivative, a dihydrobenzanthracene derivative, or a triphenylene derivative. In particular, the light-emitting layer EML may further include an anthracene derivative or a pyrene derivative.

[0127] The light-emitting layer EML includes a common material known in the art as a host material. For example, the light-emitting layer EML may include at least one of DPEPO (bis[2-(diphenylphosphino)phenyl]ether oxide), CBP (4,4-bis(carbazol-9-yl)biphenyl), mCP (1,3-bis(carbazol-9-yl)benzene), PPF (2,8-bis(diphenylphosphoryl)dibenzo[b,d]furan), TCTA (tris(4-carbazolyl-9-ylphenyl)amine), and TPBi (1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene) as a host material. However, the light-emitting layer EML may include, but is not limited to, at least one of Alq 3 (tris(8-hydroxyquinolino)aluminum), CBP (4,4'-bis(N-carbazolyl)-1,1'-biphenyl), PVK (poly(n-vinylcarbazole), ADN (9,10-di(naphthalen-2-yl)anthracene), TCTA (tris(4-carbazolyl-9-ylphenyl)amine), TPBi (1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene), TBADN (3-tert-butyl-9, 10-Di(naphth-2-yl)anthracene), DSA (Distyrylarylene), CDBP (4,4'-Bis(9-carbazolyl)-2,2'-dimethyl-biphenyl), MADN (2-Methyl-9,10-bis(naphthalen-2-yl)anthracene), DPEPO (Bis[2-(diphenylphosphino)phenyl]ether oxide), CP1 (Hexaphenylcyclotriphosphazene), UGH2 (1,4-Bis(triphenylsilyl)benzene), DPSiO 3 (Hexaphenylcyclotrisiloxane), DPSiO 4 (octaphenylcyclotetrasiloxane), PPF (2,8-bis(diphenylphosphoryl)dibenzofuran), etc. may be used as the host material.

[0128] In one embodiment, the light emitting layer EML may further include known dopant materials. For example, the emitting layer EML may include, as a dopant material, a styryl derivative (e.g., 1,4-bis[2-(3-N-ethylcarbazolyl)vinyl]benzene (BCzVB), 4-(di-p-tolylamino)-4'-[(di-p-tolylamino)styryl]stilbene (DPAVB), N-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl)naphthalen-2-yl)vinyl)phenyl)-N-phenylbenzenamine (N-BDAVBi), perylene and its derivatives (e.g., 2,5,8,11-tetra-t-butylperylene (TBP)), pyrene and its derivatives (e.g., 1,1-dipyrene, 1,4-dipyrenylbenzene, 1,4-bis(N,N-diphenylamino)pyrene), or the like. The emitting layer EML may further include a thermally activated delayed fluorescent dopant.

[0129] 1 to 3, the electron transport region ETR is disposed on the emission layer EML. The electron transport region ETR includes at least one of a hole blocking layer HBL, an electron transport layer ETL, and an electron injection layer EIL, but the embodiment of the present disclosure is not limited thereto.

[0130] The electron transport region ETR has a single layer made of a single material, a single layer made of a plurality of different materials, or a multilayer structure having a plurality of layers made of a plurality of different materials.

[0131] For example, the electron transport region ETR may have a single layer structure of an electron injection layer EIL or an electron transport layer ETL, or may have a single layer structure made of an electron injection material and an electron transport material. The electron transport region ETR may have a single layer structure made of a plurality of different materials, and may have a structure of an electron transport layer ETL / electron injection layer EIL or a hole blocking layer HBL / electron transport layer ETL / electron injection layer EIL stacked in order from the light emitting layer EML, but is not limited thereto. The thickness of the electron transport region ETR may be, for example, about 100 nm to about 150 nm.

[0132] The electron transport region ETR can be formed using various methods such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) method, inkjet printing, laser printing, and laser induced thermal imaging (LITI).

[0133] When the electron transport region ETR includes an electron transport layer ETL, the electron transport region ETR includes an anthracene-based compound. However, the electron transport region ETR is not limited thereto, and may include, for example, Alq 3 (Tris(8-hydroxyquinolinato)aluminum), 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, 2,4,6-tris(3'-pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzoimidazolyl-1-ylphenyl)-9,10-dinaphthylanthracene, TPBi(1,3,5-tri(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene), BCP(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), Bph en (4,7-diphenyl-1,10-phenanthroline), TAZ (3-(4-biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole), NTAZ (4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole), tBu-PBD (2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole), BAlq (bis(2-methyl-8-quinolinolato-N1,O8)-(1,1'-biphenyl-4-olato)aluminum), Bebq 2 (beryllium bis(benzoquinoline-10-olate), ADN (9,10-di(naphthalene-2-yl)anthracene), and a mixture thereof. The electron transport layer ETL may have a thickness of about 10 nm to about 100 nm, for example, about 15 nm to about 50 nm. When the thickness of the electron transport layer HTL satisfies the above-mentioned range, sufficient electron transport properties can be obtained without a substantial increase in driving voltage.

[0134] When the electron transport region ETR includes an electron injection layer EIL, the electron transport region ETR may be a metal halide such as LiF, NaCl, CsF, RbCl, or RbI, a lanthanide metal such as Yb, or Li 2 Metal oxides such as O, BaO, or LiQ (lithium quinolate) may be used, but are not limited thereto. The electron injection layer EIL may also be made of a material in which an electron transport material and an insulating organo metal salt are mixed. The organo metal salt is a material having an energy band gap of about 4 eV or more. In detail, for example, the organo metal salt includes metal acetate, metal benzoate, metal acetoacetate, metal acetylacetonate, or metal stearate. The thickness of the electron injection layer EIL is about 0.1 nm to about 10 nm, or about 0.3 nm to about 9 nm. When the thickness of the electron injection layer EIL satisfies the above-mentioned range, sufficient electron injection characteristics can be obtained without a substantial increase in driving voltage.

[0135] The electron transport region ETR may include a hole blocking layer HBL as described above. The hole blocking layer HBL may include at least one of, for example, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) and Bphen (4,7-diphenyl-1,10-phenanthroline), but is not limited thereto. The thickness of the hole blocking layer HBL is not particularly limited, but may be, for example, about 1 nm to about 30 nm.

[0136] The second electrode EL2 is disposed on the electron transport region ETR. The second electrode EL2 is a common electrode or a negative electrode. The second electrode EL2 is a transmissive electrode, a semi-transmissive electrode, or a reflective electrode. If the second electrode EL2 is a transmissive electrode, the second electrode EL2 is made of a transparent metal oxide, such as ITO, IZO, ZnO, ITZO, etc.

[0137] If the second electrode EL2 is a semi-transmissive electrode or a reflective electrode, the second electrode EL2 contains Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, or a compound or mixture containing these (for example, an alloy of Ag and Mg). The second electrode EL2 may have a multi-layer structure including a reflective film or semi-transmissive film made of the above-mentioned material, and a transparent conductive film made of ITO, IZO, ZnO, ITZO, or the like. The thickness of the second electrode EL2 may be about 100 nm to about 1000 nm, for example, about 150 nm to about 500 nm.

[0138] Although not shown, the second electrode EL2 may be electrically connected to an auxiliary electrode. When the second electrode EL2 is connected to the auxiliary electrode, the resistance of the second electrode EL2 can be reduced.

[0139] Meanwhile, although not shown, a capping layer (not shown) is further disposed on the second electrode EL2 of the organic electroluminescent device 10 according to an embodiment. The capping layer (not shown) may be, for example, α-NPD, NPB, TPD, m-MTDATA, Alq 3 , CuPc, TPD15 (N4,N4,N4',N4'-tetra(biphenyl-4-yl)biphenyl-4,4'-diamine), TCTA (tris(4-carbazol-9-ylphenyl)amine), or N,N'-bis(naphthalen-1-yl), and the like.

[0140] The organometallic compound according to the embodiment described above is included in an organic layer other than the emitting layer EML as a material for the organic electroluminescent device 10. The organic electroluminescent device 10 according to the embodiment of the present invention may include the organometallic compound described above in at least one organic layer disposed between the first electrode EL1 and the second electrode EL2, or in a capping layer (not shown) disposed on the second electrode EL2.

[0141] In the organic electroluminescent device 10, when a voltage is applied to the first electrode EL1 and the second electrode EL2, holes injected from the first electrode EL1 move to the emission layer EML via the hole transport region HTR, and electrons injected from the second electrode EL2 move to the emission layer EML via the electron transport region ETR. The electrons and holes recombine in the emission layer EML to generate excitons, and emit light when the excitons fall from the excited state to the ground state. EXAMPLES

[0142] Hereinafter, an organometallic compound according to an embodiment of the present invention and an organic electroluminescent device including the organometallic compound according to an embodiment of the present invention will be described in detail with reference to examples and comparative examples. Also, the following examples are merely illustrative for the purpose of aiding understanding of the present invention, and the scope of the present invention is not limited thereto.

[0143] The organometallic compound according to an embodiment of the present invention may be synthesized, for example, as follows: However, the method for synthesizing the organometallic compound according to an embodiment of the present invention is not limited thereto.

[0144] 1-1. Synthesis of compound 9 The organometallic compound 9 according to one embodiment is synthesized, for example, according to the following reaction scheme 1. [Reaction Scheme 1] [ka] JPEG0007617726000228.jpg27163

[0145] (Synthesis of intermediate 9-1) 7.2g (50mmol) of 2-phenyl-1H-imidazole, 14.0g (75mmol) of 3-bromoanisole, 23g (100mmol) of tripotassium phosphate, 1.83g (10mmol) of CuI, and 1.17g (10mmol) of picolinic acid were placed in a reaction vessel and suspended in 100mL of dimethylsulfoxide. The reaction mixture was heated and stirred at 160°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, 300mL of distilled water was added, and the mixture was extracted with ethyl acetate. The extracted organic layer was washed with a saturated aqueous sodium chloride solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain 10.5g (42mmol) of intermediate [9-1].

[0146] (Synthesis of intermediate 9-2) 10.5g (42mmol) of intermediate [9-1] was suspended in excess bromic acid solution. The reaction mixture was heated and stirred at 110°C for 24 hours. After the reaction was completed, it was cooled to room temperature and neutralized by adding a titration amount of sodium bicarbonate. 300mL of distilled water was added and extracted with ethyl acetate. The extracted organic layer was washed with a saturated sodium chloride aqueous solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain 8.5g (36mmol) of intermediate [9-2].

[0147] (Synthesis of intermediate 9-3) 14.8g (60mmol) of 2-bromocarbazole, 14.2g (90mmol) of 2-bromopyridine, 27.6g (120mmol) of tripotassium phosphate, 2.2g (12mmol) of CuI, and 1.4g (12mmol) of picolinic acid were placed in a reaction vessel and suspended in 120mL of dimethylsulfoxide. The reaction mixture was heated and stirred at 160°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, 300mL of distilled water was added, and the mixture was extracted with ethyl acetate. The extracted organic layer was washed with a saturated aqueous sodium chloride solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain 15.5g (48mmol) of intermediate [9-3].

[0148] (Synthesis of intermediate 9-4) 8.5g (36mmol) of intermediate [9-2], 15.5g (48mmol) of intermediate [9-3], 16.6g (72mmol) of tripotassium phosphate, 1.3g (7.2mmol) of CuI, and 0.8g (7.2mmol) of picolinic acid were placed in a reaction vessel and suspended in 100mL of dimethyl sulfoxide. The reaction mixture was heated and stirred at 160°C for 72 hours. After the reaction was completed, the mixture was cooled to room temperature, 300mL of distilled water was added, and the mixture was extracted with ethyl acetate. The extracted organic layer was washed with a saturated aqueous sodium chloride solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain 13.1g (27mmol) of intermediate [9-4].

[0149] (Synthesis of intermediate 9-5) 13.1g (27mmol) of intermediate [9-4] was suspended in excess iodomethane. The reaction mixture was heated and stirred at 110°C for 24 hours. After the reaction was completed, it was cooled to room temperature and the solid formed was filtered and washed with ether. The washed solid was separated using column chromatography to obtain 10.7g (17mmol) of intermediate [9-5].

[0150] (Synthesis of intermediate 9-6) 10.7g (17mmol) of intermediate [9-5] and 8.3g (51mmol) of ammonium hexafluorophosphate were placed in a reaction vessel and suspended in a mixture of 150mL of methyl alcohol and 150mL of water. The reaction mixture was stirred at room temperature for 24 hours. After the reaction was completed, the solid produced was filtered and washed with ether. The washed solid was dried to obtain 9.0g (14mmol) of intermediate [9-6].

[0151] (Synthesis of Compound 9) 9.0g (14mmol) of intermediate [9-6], 5.8g (15.4mmol) of dichloro(1,5-cyclooctadiene)platinum(II), and 3.4g (42mmol) of sodium nitrate were suspended in 220mL of dioxane. The reaction mixture was heated and stirred at 110℃ for 72 hours. After the reaction was completed, the mixture was cooled to room temperature, 100mL of distilled water was added, and the mixture was extracted with ethyl acetate. The extracted organic layer was washed with a saturated aqueous sodium chloride solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain 0.9g (1.3mmol) of the target compound.

[0152] 1-2. Synthesis of compound 16 [Reaction Scheme 2] [ka] JPEG0007617726000230.jpg33162

[0153] (Synthesis of compound 16) Compound 16 (0.7 g, 1.2 mmol) was obtained using the same method as in Synthesis Example 1, except that 1H-1,2,3-triazole was used instead of 2-phenyl-1H-imidazole.

[0154] 1-3. Synthesis of compound 46 [Reaction Scheme 3] [ka] JPEG0007617726000232.jpg33162

[0155] (Synthesis of compound 46) Compound 46 (0.6 g, 0.9 mmol) was obtained using the same method as in Synthesis Example 1, except that 1H-tetrazole was used instead of 2-phenyl-1H-imidazole.

[0156] 1-4. Synthesis of compound 71 [Reaction Scheme 4] [ka] JPEG0007617726000234.jpg38163

[0157] (Synthesis of intermediate 71-1) 3.4g (50mmol) of imidazole, 14.0g (75mmol) of 3-bromoanisole, 23g (100mmol) of tripotassium phosphate, 1.83g (10mmol) of CuI, and 1.17g (10mmol) of picolinic acid were placed in a reaction vessel and suspended in 100mL of dimethylsulfoxide. The reaction mixture was heated and stirred at 160°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, 300mL of distilled water was added, and the mixture was extracted with ethyl acetate. The extracted organic layer was washed with a saturated aqueous sodium chloride solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain 7.8g (45mmol) of intermediate [71-1].

[0158] (Synthesis of intermediate 71-2) 7.8g (45mmol) of intermediate [71-1] was suspended in excess bromic acid solution. The reaction mixture was heated and stirred at 110℃ for 24 hours. After the reaction was completed, it was cooled to room temperature and neutralized by adding a titration amount of sodium bicarbonate. 300mL of distilled water was added and extracted with ethyl acetate. The extracted organic layer was washed with a saturated sodium chloride aqueous solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain 6.2g (39mmol) of intermediate [71-2].

[0159] (Synthesis of intermediate 71-3) 3.5g (50mmol) of 1H-1,2,3-triazole, 17.7g (75mmol) of 1,3-dibromobenzene, 23g (100mmol) of tripotassium phosphate, 1.83g (10mmol) of CuI, and 1.17g (10mmol) of picolinic acid were placed in a reaction vessel and suspended in 100mL of dimethylsulfoxide. The reaction mixture was heated and stirred at 160°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, 300mL of distilled water was added, and the mixture was extracted with ethyl acetate. The extracted organic layer was washed with a saturated aqueous sodium chloride solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain 9.9g (44mmol) of intermediate [71-3].

[0160] (Synthesis of intermediate 71-4) 6.2g (39mmol) of intermediate [71-2], 9.9g (44mmol) of intermediate [71-3], 18.0g (78mmol) of tripotassium phosphate, 1.4g (7.8mmol) of CuI, and 0.9g (7.8mmol) of picolinic acid were placed in a reaction vessel and suspended in 100mL of dimethyl sulfoxide. The reaction mixture was heated and stirred at 160°C for 72 hours. After the reaction was completed, the mixture was cooled to room temperature, 300mL of distilled water was added, and the mixture was extracted with ethyl acetate. The extracted organic layer was washed with a saturated aqueous sodium chloride solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain 9.3g (31mmol) of intermediate [71-4].

[0161] (Synthesis of intermediate 71-5) 9.3g (31mmol) of intermediate [71-4] was suspended in excess iodomethane. The reaction mixture was heated and stirred at 110°C for 24 hours. After the reaction was completed, it was cooled to room temperature, and the solid formed was filtered and washed with ether. The washed solid was separated by recrystallization to obtain 10.9g (19mmol) of the target compound.

[0162] (Synthesis of intermediate 71-6) 10.9g (19mmol) of intermediate [71-5] and 12.4g (76mmol) of ammonium hexafluorophosphate were placed in a reaction vessel and suspended in a mixture of 200mL of methyl alcohol and 200mL of water. The reaction mixture was stirred at room temperature for 24 hours. After the reaction was completed, the solid produced was filtered and washed with ether. The washed solid was dried to obtain 8.2g (13mmol) of intermediate [71-6].

[0163] (Synthesis of Compound 71) 8.2g (13mmol) of intermediate [71-6], 5.4g (14.3mmol) of dichloro(1,5-cyclooctadiene)platinum(II), and 6.3g (78mmol) of sodium nitrate were suspended in 220mL of dioxane. The reaction mixture was heated and stirred at 110℃ for 72 hours. After the reaction was completed, the mixture was cooled to room temperature, 100mL of distilled water was added, and the mixture was extracted with ethyl acetate. The extracted organic layer was washed with a saturated aqueous sodium chloride solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain 0.4g (0.7mmol) of compound 71.

[0164] 1-5. Synthesis of compound 87 [Reaction Scheme 5] [ka] JPEG0007617726000236.jpg34163

[0165] (Synthesis of intermediate 87-1) 3.4g (50mmol) of imidazole, 17.8g (75mmol) of 3,5-dibromopyridine, 23g (100mmol) of tripotassium phosphate, 1.83g (10mmol) of CuI, and 1.17g (10mmol) of picolinic acid were placed in a reaction vessel and suspended in 100mL of dimethylsulfoxide. The reaction mixture was heated and stirred at 160℃ for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, 300mL of distilled water was added, and the mixture was extracted with ethyl acetate. The extracted organic layer was washed with a saturated aqueous sodium chloride solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain 9.6g (43mmol) of intermediate [87-1].

[0166] (Synthesis of intermediate 87-2) 9.9g (50mmol) of 2-methoxycarbazole, 11.8g (75mmol) of bromobenzene, 23g (100mmol) of tripotassium phosphate, 1.83g (10mmol) of CuI, and 1.17g (10mmol) of picolinic acid were placed in a reaction vessel and suspended in 100mL of dimethylsulfoxide. The reaction mixture was heated and stirred at 160°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, 300mL of distilled water was added, and the mixture was extracted with ethyl acetate. The extracted organic layer was washed with a saturated aqueous sodium chloride solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain 12.3g (45mmol) of intermediate [87-2].

[0167] (Synthesis of intermediate 87-3) 12.3g (45mmol) of intermediate [87-2] was suspended in excess bromic acid solution. The reaction mixture was heated and stirred at 110℃ for 24 hours. After the reaction was completed, it was cooled to room temperature and neutralized by adding a titration of sodium bicarbonate. 300mL of distilled water was added and extracted with ethyl acetate. The extracted organic layer was washed with a saturated sodium chloride aqueous solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain 9.1g (35mmol) of intermediate [87-3].

[0168] (Synthesis of intermediate 87-4) 9.6g (43mmol) of intermediate [87-1], 9.1g (35mmol) of intermediate [87-3], 16.2g (70mmol) of tripotassium phosphate, 1.3g (7.0mmol) of CuI, and 0.8g (7.0mmol) of picolinic acid were placed in a reaction vessel and suspended in 100mL of dimethyl sulfoxide. The reaction mixture was heated and stirred at 160°C for 72 hours. After the reaction was completed, the mixture was cooled to room temperature, 300mL of distilled water was added, and the mixture was extracted with ethyl acetate. The extracted organic layer was washed with a saturated aqueous sodium chloride solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain 10.5g (26mmol) of intermediate [87-4].

[0169] (Synthesis of intermediate 87-5) 10.5g (26mmol) of intermediate [87-4] was suspended in excess iodomethane. The reaction mixture was heated and stirred at 110℃ for 24 hours. After the reaction was completed, it was cooled to room temperature, and the solid formed was filtered and washed with ether. The washed solid was separated by recrystallization to obtain 9.6g (14mmol) of intermediate [87-5].

[0170] (Synthesis of intermediate 87-6) 9.6g (14mmol) of intermediate [87-5] and 9.1g (56mmol) of ammonium hexafluorophosphate were placed in a reaction vessel and suspended in a mixture of 120mL of methyl alcohol and 120mL of water. The reaction mixture was stirred at room temperature for 24 hours. After the reaction was completed, the solid produced was filtered and washed with ether. The washed solid was dried to obtain 6.5g (9mmol) of intermediate [87-6].

[0171] (Synthesis of compound 87) 6.5g (9mmol) of intermediate [87-6], 3.7g (9.9mmol) of dichloro(1,5-cyclooctadiene)platinum(II), and 4.4g (54mmol) of sodium nitrate were suspended in 140mL of dioxane. The reaction mixture was heated and stirred at 110℃ for 72 hours. After the reaction was completed, the mixture was cooled to room temperature, 100mL of distilled water was added, and the mixture was extracted with ethyl acetate. The extracted organic layer was washed with a saturated aqueous sodium chloride solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain 0.6g (0.9mmol) of the target compound.

[0172] 1-6. Synthesis of Compound 96 [ka]

[0173] (Synthesis of intermediate 96-1) 5.9g (50mmol) of 2H-indazole, 17.7g (75mmol) of 1,3-dibromobenzene, 23g (100mmol) of tripotassium phosphate, 1.83g (10mmol) of CuI, and 1.17g (10mmol) of picolinic acid were placed in a reaction vessel and suspended in 100mL of dimethylsulfoxide. The reaction mixture was heated and stirred at 160℃ for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, 300mL of distilled water was added, and the mixture was extracted with ethyl acetate. The extracted organic layer was washed with a saturated aqueous sodium chloride solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain intermediate [96-1]. (Yield 69%)

[0174] (Synthesis of intermediate 96-2) 11.7g (43mmol) of intermediate [96-1], 9.1g (35mmol) of intermediate [96-5], 16.2g (70mmol) of tripotassium phosphate, 1.3g (7.0mmol) of CuI, and 0.8g (7.0mmol) of picolinic acid were placed in a reaction vessel and suspended in 100mL of dimethylsulfoxide. The reaction mixture was heated and stirred at 160°C for 72 hours. After the reaction was completed, the mixture was cooled to room temperature, 300mL of distilled water was added, and the mixture was extracted with ethyl acetate. The extracted organic layer was washed with a saturated aqueous sodium chloride solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain intermediate [96-2]. (Yield 55%)

[0175] (Synthesis of intermediate 96-3) 9.0g (20mmol) of intermediate [96-2] was suspended in excess iodomethane. The reaction mixture was heated and stirred at 110℃ for 24 hours. After the reaction was completed, it was cooled to room temperature, and the solid formed was filtered and washed with ether. The washed solid was separated by recrystallization to obtain intermediate [96-3]. (Yield 55%)

[0176] (Synthesis of intermediate 96-4) 8.3g (14mmol) of intermediate [96-3] and 9.1g (56mmol) of ammonium hexafluorophosphate were placed in a reaction vessel and suspended in a mixture of 120mL of methyl alcohol and 120mL of water. The reaction mixture was stirred at room temperature for 24 hours. After the reaction was completed, the solid produced was filtered and washed with ether. The washed solid was dried to obtain intermediate [96-4]. (Yield 90%)

[0177] (Synthesis of Compound 96) 5.5g (9mmol) of intermediate [96-4], 3.7g (9.9mmol) of dichloro(1,5-cyclooctadiene)platinum(II), and 4.4g (54mmol) of sodium nitrate were suspended in 140mL of dioxane. The reaction mixture was heated and stirred at 110℃ for 72 hours. After the reaction was completed, the mixture was cooled to room temperature, 100mL of distilled water was added, and the mixture was extracted with ethyl acetate. The extracted organic layer was washed with a saturated aqueous sodium chloride solution and dried over sodium sulfate. The residue after removing the solvent was separated using column chromatography to obtain compound 96. (Yield 35%)

[0178] 1-7. Synthesis of Compound 98 [ka] Compound 98 was obtained using the same method as in the synthesis example of compound 96 above, except that intermediate [53-B] was used instead of intermediate [9-3]. (Yield 48%)

[0179] 1-8. Synthesis of compound 113 [ka] Compound 113 was obtained using the same method as in the synthesis example of compound 96 above, except that intermediate [113-1] was used instead of 1,3-dibromobenzene. (Yield 41%)

[0180] The 1H NMR and MS / FAB data of the compounds synthesized through the above synthesis examples are shown in Table 1 below. [Table 1]

[0181] 1-A. Synthesis of Compound 1-1 The organometallic compound 1-1 according to one embodiment of the present invention can be synthesized, for example, according to the following reaction scheme 1. [Reaction Scheme 1-A] [ka]

[0182] (Synthesis of intermediate 1-A) 1.89 (16.0 mmol) of imidazo[1,2-a]pyridine, 3.77 (16.0 mmol) of 1,3-dibromobenzene, 0.18 g (0.8 mmol) of palladium acetate, and 3.14 g (32.0 mmol) of potassium acetate were suspended in 60 mL of dimethylacetamide solvent, heated to 140°C, and stirred for a day. The reaction mixture was extracted with methylene chloride and distilled water. The organic phase was washed three times with distilled water, dried over magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrated liquid was purified by column chromatography to obtain intermediate [1-A]. (Yield 68%)

[0183] (Synthesis of intermediate 1-C) The synthesized intermediate [1-A] and intermediate [1-B] (1.0 equivalent), (0.1 equivalent), potassium phosphate (2.0 equivalents), and L-proline (0.1 equivalents) were suspended in 100 mL of dimethylformamide solvent, heated to 160°C, and stirred for 12 hours. After the reaction was completed, the solvent was removed under reduced pressure, and the mixture was extracted with methylene chloride and distilled water. The organic phase was washed three times with distilled water, dried over magnesium sulfate, filtered, and then concentrated under reduced pressure. The concentrated liquid was purified by column chromatography to obtain intermediate [1-C]. (Yield 76%)

[0184] (Synthesis of intermediate 1-D) Intermediate [1-C] was dissolved in toluene, iodomethane (1.2 equivalents) was added, and the mixture was heated to 110°C and stirred for 12 hours. After the reaction was completed, the solvent was removed under reduced pressure, and the concentrated solution was purified by column chromatography to obtain intermediate [1-D]. (Yield 88%)

[0185] (Synthesis of intermediate 1-E) Intermediate [1-D] was dissolved in a 4:1 mixed solvent of methanol and distilled water, and ammonium hexafluorophosphate (1.05 equivalents) was added. The resulting solid was stirred at room temperature for 12 hours. After filtration, it was washed with distilled water and diethyl ether to obtain intermediate [1-E]. (Yield 90%)

[0186] (Synthesis of Compound 1-1) Intermediate [1-E] and sodium acetate (3.0 equivalents), Pt(COD)Cl 2 (1.05 equivalents) was suspended in 1,4-dioxane solvent. The reaction mixture was heated to 120° C. and stirred for 36 hours. After the reaction was completed, the solvent was removed under reduced pressure. Compound 1-1 was obtained by column purification (yield 40%).

[0187] 1-B. Synthesis of Compound 1-53 [Reaction Scheme 2-A] [ka]

[0188] (Synthesis of intermediate 53-A) Intermediate [53-A] was obtained using the same method as intermediate [1-A], except that 1,3-dibromo-5-(dibutyl)benzene was used instead of 1,3-dibromobenzene. (Yield 69%)

[0189] (Synthesis of intermediate 53-C) Intermediate [53-C] was obtained using the same method as intermediate [1-C], except that intermediate [53-B] was used instead of intermediate [1-B]. (Yield 66%)

[0190] (Synthesis of intermediate 53-D) Intermediate [53-D] was obtained using the same method as for the synthesis of intermediate [1-D] above, except that intermediate [53-C] was used instead of intermediate [1-C]. (Yield 83%)

[0191] (Synthesis of intermediate 53-E) Intermediate [53-E] was obtained using the same method as for the synthesis of intermediate [1-E] above, except that intermediate [53-D] was used instead of intermediate [1-D]. (Yield 95%)

[0192] (Synthesis of compound 53-1) Compound 1-53 was obtained using the same method as compound 1-1 above, except that intermediate [53-E] was used instead of intermediate [1-E]. (Yield 45%)

[0193] 1-C. Synthesis of Compound 1-87 [ka] Compound 1-87 was obtained using the same method as that for compound 53-1, except that 3',5'-dibromo-2,4,6-triisopropyl-1,1'-diphenyl was used instead of 1,3-dibromo-5-(dibutyl)benzene and deuterium-substituted iodomethane was used instead of iodomethane.

[0194] 1-D. Synthesis of Compound 1-110 [ka] Compound 1-110 was obtained using the same method as the synthesis of compound 1-1, except that 3-(dibutyl)-5-(3,5-dimethyl-1H-pyrazol-1-yl)phenol was used instead of intermediate [1-B].

[0195] 1-E. Synthesis of Compound 1-124 [Reaction Scheme 3-A] [ka]

[0196] Synthesis of (Intermediate 124-A) 1.13g (12.0mmol) of 2-aminopyridine, 1.99g (10.0mmol) of 1-(3-bromophenyl)ethan-1-one, 2.0mmol of copper iodide, and 30mL of 1,4-dioxane were suspended, heated to 100℃, and stirred for 14 hours. The reaction mixture was concentrated under reduced pressure. The concentrate was purified by column chromatography to obtain intermediate [124-A]. (Yield 68%)

[0197] (Synthesis of Intermediate 124-C) Intermediate [124-C] was obtained using the same method as for the synthesis of intermediate [53-C] above, except that intermediate [124-A] was used instead of intermediate [53-A]. (Yield 62%)

[0198] (Synthesis of intermediate 124-D) Intermediate [124-D] was obtained using the same method as the synthesis of intermediate [53-D] above, except that intermediate [124-C] was used instead of intermediate [53-C]. (Yield 81%)

[0199] (Synthesis of intermediate 124-E) Intermediate [124-E] was obtained using the same method as for the synthesis of intermediate [53-E], except that intermediate [124-D] was used instead of intermediate [53-D]. (Yield 92%)

[0200] (Synthesis of Compound 1-124) Compound 1-124 was obtained using the same method as compound 1-53, except that intermediate [124-E] was used instead of intermediate [53-E]. (Yield 41%)

[0201] 1-F. Synthesis of Compound 1-148 [ka] Compound 1-148 was obtained using the same method as the synthesis of compound 1-124, except that 5-(3,5-dimethyl)-1H-pyrazol-1-yl)pyridin-3-ol was used instead of intermediate [53-B].

[0202] 2. Fabrication and evaluation of organic electroluminescent devices containing organometallic compounds 2-1. Examples of organic electroluminescent devices containing organometallic compounds The organic electroluminescent devices of Examples 1 to 14 and Comparative Examples 1 to 5 were fabricated using the compounds of Examples 9, 16, 46, 71, 87, 96, 98, 113, 1-1, 1-53, 1-87, 1-110, 1-124, and 1-148 and the compounds of Comparative Examples C1 to C5 as dopant materials in the emitting layer EML. Comparative Example C1 was a green phosphorescent dopant, Ir(PPy) 3 Comparative Example Compound C2 is a green phosphorescent dopant that does not contain a group derived from a carbene, and Comparative Example Compounds C3 to C5 are green phosphorescent dopants that do not contain a group derived from a mesoionic carbene. (Example Compounds) [ka] [ka] [ka] [ka] (Comparative Example Compound) [ka] JPEG0007617726000252.jpg37104

[0203] (Fabrication of Organic Electroluminescent Device) For the organic electroluminescence devices of Examples 1 to 14 and Comparative Examples 1 to 5, an ITO (Corning) glass substrate was cut to a size of about 50 mm x 50 mm x 0.7 mm, and ultrasonically cleaned for 5 minutes using isopropyl alcohol and distilled water, respectively, and then irradiated with ultraviolet light for about 30 minutes and exposed to ozone for cleaning, to form a first electrode EL1 with a thickness of about 120 nm in a vacuum deposition apparatus. A hole injection layer HIL with a thickness of about 60 nm was formed using 2-TNATA, and a hole transport layer HTL with a thickness of about 30 nm was formed using NPB. Next, a light emitting layer EML with a thickness of 30 nm was formed by doping mCBP with 10% of the Example compound or Comparative Example compound, and a hole blocking layer HBL with a thickness of 5 nm was formed using TPSO1 (diphenyl[4-(triphenylsilyl)phenyl]phosphine oxide), and a hole blocking layer HBL with a thickness of 5 nm was formed using Alq 3 An electron transport layer ETL having a thickness of 30 nm was formed using LiF. Next, an electron injection layer EIL having a thickness of 1 nm was formed using LiF, and a second electrode EL2 having a thickness of 300 nm was formed using Al. Each layer was formed by vacuum deposition.

[0204] (Evaluation of the characteristics of organic electroluminescent devices) The characteristics of the fabricated organic electroluminescent device were evaluated using a luminance distribution characteristic measuring device. In order to evaluate the characteristics of the organic electroluminescent device according to the examples and comparative examples, the driving voltage, luminance, efficiency, emission wavelength, and lifetime (T 80 ) was measured. Table 2 shows the driving voltage (V), current density (50 mA / cm) and 2 The current efficiency (Cd / A) and luminance (cd / m 2 ) is also shown. The element lifespan (T 80 ) is shown. 80 ) is 40mA / cm 2 The organic electroluminescent device was continuously driven at a current density of 1000 s to 2000 s, and the luminance spectrum of the example and comparative example was measured using a spectroradiometer. The emission peak, which is the maximum emission wavelength, was measured from the measured luminance spectrum. [Table 2]

[0205] Referring to the results in Table 2, it can be seen that by applying the metal organic compound according to one embodiment of the present invention to the organic electroluminescent device 10 as an emission layer EML material that emits green light, the device can achieve high efficiency, high brightness, low driving voltage, and long life.

[0206] Referring to the results of Examples 1 to 14 and Comparative Examples 1 to 5, the Examples including an organometallic compound according to an embodiment having a group derived from a mesoionic carbene in the light-emitting layer achieve higher efficiency, higher brightness, lower driving voltage, and longer life than the Comparative Examples including an organometallic compound not including a group derived from a mesoionic carbene.

[0207] Referring to Comparative Example 1, a known green phosphorescent dopant material, Ir(PPy) 3 It can be seen that the effect of the embodiment is superior to that of the case where the above-mentioned is used.

[0208] Referring to Comparative Example 2, it can be seen that the effect of the Example is superior to that of Comparative Example 2 in which a metal organic compound containing a metal atom and four ligands bonded to the metal atom but not containing a group derived from a mesoionic carbene as a ligand was used as the light-emitting layer material.

[0209] Referring to Comparative Examples 3 to 5, it can be seen that the effects of the Examples are superior in terms of luminance, driving voltage, and lifespan compared to Comparative Examples 3 to 5 which use metal organic compounds that include a metal atom and four ligands bonded to the metal atom, and that include a group derived from a normal carbene as the ligand but do not include a group derived from a mesoionic carbene as the ligand.

[0210] In Figure 4, imidazole-4-indene is shown as an example of mesoionic carbene. Compared to normal carbenes, mesoionic carbenes have electrons that are more localized in the molecule. As a result, mesoionic carbenes have less stable properties than normal carbenes, which have a stable structure with non-localized electrons.

[0211] Thus, since the group derived from the mesoionic carbene has stronger σ (sigma) donor properties than the group derived from the normal carbene, the unshared electron pair is strongly bonded to the metal atom. Therefore, the organometallic compound according to an embodiment has stronger bonds than the comparative compounds C3 to C5 containing the group derived from the normal carbene, and is resistant to moisture and air and is not easily oxidized. As a result, the organometallic compound according to an embodiment is used as a light-emitting layer material of an organic electroluminescent device and has a long life. In addition, it is considered that the dd* transition of the metal atom of the organometallic compound is reduced due to the strong bonding properties, and the organic electroluminescent device including the organometallic compound according to an embodiment can achieve a low driving voltage and high brightness.

[0212] The organometallic compound according to an embodiment includes a metal atom and four ligands each bonded to the metal atom, and at least one of the four ligands includes a group derived from a mesoionic carbene. Thus, the organometallic compound according to an embodiment has a strong bond between the mesoionic carbene ligand and the metal atom. Thus, the organometallic compound according to an embodiment can be used in an emission layer of an organic electroluminescent device to achieve high efficiency, low driving voltage, high brightness, and long life. [Explanation of symbols]

[0213] 10: Organic electroluminescent element EL1: First electrode EL2: second electrode HTR: hole transport region EML: Light-emitting layer ETR: Electron transport region

Claims

1. An organometallic compound which is any one of the compounds shown in the first compound group and the second compound group below. [First compound group] 【Chemistry 1】 【Chemistry 2】 【Chemistry 3】 【Chemistry 4】 【Chemistry 5】 【Chemistry 6】 【Chemistry 7】 【Chemistry 8】 【Chemistry 9】 【Chemistry 10】 【Chemistry 11】 [Second compound group] 【Chemistry 12】 【Chemistry 13】 【Chemistry 14】 【Chemistry 15】 【Chemistry 16】 【Chemistry 17】 【Chemistry 18】 【Chemistry 19】 【Chemistry 20】 【Chemistry 21】 【Chemical 22】 【Chemistry 23】 【Chemistry 24】 【Chemistry 25】 【Chemistry 26】 【Chemical 27】 【Chemistry 28】 【Chemical 29】 【Chemistry 30】 【Chemistry 31】 【Chemistry 32】 【Chemical 33】 【Chemical 34】 【Chemistry 35】 【Chemical 36】 【Chemical 37】 【Chemical Formula 38】 【Chemical 39】 【Chemistry 40】 【Chemistry 41】 【Chemistry 42】 【Chemistry 43】 【Chemistry 44】 【Chemistry 45】 【Chemistry 46】 【Chemistry 47】 【Chemistry 48】 【Chemistry 49】 【Chemistry 50】 【Chemistry 51】 【Chemistry 52】 【Chemistry 53】 【Chemical 54】 【Chemistry 55】 【Chemistry 56】 【Chemistry 57】

2. A first electrode; a hole transport region disposed over the first electrode; a light-emitting layer disposed over the hole transport region; an electron transport region disposed over the light emitting layer; a second electrode disposed over the electron transport region; The light-emitting layer comprises the organometallic compound according to claim 1 .

3. The light-emitting layer comprises a host and a dopant, The organic electroluminescent device according to claim 2 , wherein the dopant comprises the organometallic compound.

4. The organic electroluminescent device according to claim 2 , wherein the light-emitting layer emits green phosphorescence having a central wavelength of 500 nm or more and 600 nm or less.

Images