Organometallic Compound and Organic Light-Emitting Diode Comprising the Same

Abstract

A novel organometallic compound is disclosed, in which the main ligand (L A ) has a fused-ring structure including a thiophene group. The organometallic compound is used as a dopant for a phosphorescent emitting layer of an organic light-emitting diode. Thereby, the operating voltage of the diode is reduced, and the light-emitting efficiency and lifetime of the diode are improved.

Description

Technical Field

[0001] The present disclosure relates to organometallic compounds, and more particularly, to organometallic compounds having phosphorescent properties and organic light-emitting diodes including the organometallic compounds. Background Art

[0002] As display devices are applied to various fields, the interest in display devices is increasing day by day. One of the display devices is an organic light-emitting display device including rapidly developing organic light-emitting diodes (OLEDs).

[0003] In an organic light-emitting diode, when charges are injected into a light-emitting layer formed between a positive electrode and a negative electrode, electrons and holes recombine with each other in the light-emitting layer to form excitons, and thus the energy of the excitons is converted into light. Accordingly, the organic light-emitting diode emits light. Compared with conventional display devices, the organic light-emitting diode can operate at a low voltage, consume relatively less power, exhibit excellent colors, and can be used in various ways since a flexible substrate can be applied. In addition, the size of the organic light-emitting diode can be freely adjusted. Summary of the Invention

[0004] Compared with a liquid crystal display (LCD), an organic light-emitting diode (OLED) has excellent viewing angles and contrast ratios, and is lightweight and ultrathin since an OLED does not require a backlight. The organic light-emitting diode includes a plurality of organic layers between a negative electrode (electron injection electrode; cathode) and a positive electrode (hole injection electrode; anode). The plurality of organic layers may include a hole injection layer, a hole transport layer, a hole transport assisting layer, an electron blocking layer, and a light-emitting layer, an electron transport layer, and the like.

[0005] In such an organic light-emitting diode structure, when a voltage is applied between the two electrodes, electrons and holes are respectively injected into the light-emitting layer from the negative electrode and the positive electrode, thereby generating excitons in the light-emitting layer, and then dropping to the ground state to emit light.

[0006] Organic materials used in organic light-emitting diodes can be mainly classified into light-emitting materials and charge transport materials. The light-emitting materials are important factors determining the light-emitting efficiency of organic light-emitting diodes. The light-emitting materials have high quantum efficiency, excellent electron and hole mobilities, and are uniformly and stably present in the light-emitting layer. The light-emitting materials can be classified into light-emitting materials emitting blue light, red light, and green light according to the color of light. The color generating materials may include a host and a dopant to improve color purity and light-emitting efficiency through energy transfer.

[0007] In recent years, there has been a trend to use phosphorescent materials instead of fluorescent materials for the light-emitting layer. When using fluorescent materials, about 25% of the singlet excitons generated in the light-emitting layer are used for light emission, while 75% of the triplet excitons generated in the light-emitting layer are mostly dissipated in the form of heat. However, when using phosphorescent materials, both singlet and triplet excitons are used for light emission.

[0008] Generally, organometallic compounds are used as phosphorescent materials in organic light-emitting diodes. There is a continuous need to research and develop phosphorescent materials to solve the problems of low efficiency and lifespan.

[0009] Therefore, an object of the present invention is to provide an organometallic compound capable of reducing the operating voltage and improving efficiency and lifespan, and an organic light-emitting diode including an organic light-emitting layer containing the organometallic compound.

[0010] The object of the present disclosure is not limited to the above object. Other unmentioned objects and advantages of the present disclosure can be understood based on the following description, and can be more clearly understood based on the exemplary embodiments of the present disclosure. In addition, it is easily understood that the objects and advantages of the present disclosure can be achieved by using the means shown in the claims and their combinations.

[0011] To achieve the above object, the present disclosure provides an organometallic compound having a novel structure represented by the following Chemical Formula 1, an organic light-emitting diode in which the light-emitting layer contains the organometallic compound as a dopant, and an organic light-emitting display device including the organic light-emitting diode:

[0012] Ir(L A ) m (L B ) n (Chemical Formula 1)

[0013] Wherein in Chemical Formula 1,

[0014] L A can be represented by one selected from the group consisting of the following Chemical Formulas 2-1 to 2-6,

[0015] L B can be a bidentate ligand represented by the following Chemical Formula 3,

[0016] m can be 1, 2 or 3, n can be 0, 1 or 2, and the sum of m and n can be 3,

[0017]

[0018]

[0019]

[0020] In each of Chemical Formulas 2-1 to 2-6,

[0021] X may represent one selected from the group consisting of -CH 2 -, oxygen, -NH-, and sulfur,

[0022] R 1-1 、R 1-2 、R 1-3 、R 1-4 、R 2-1 、R 2-2 、R 3-1 、R 3-2 、R 4-1 and R 4-2 each may independently represent one selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, aralkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, thioalkyl, sulfinyl, sulfonyl, phosphino, and combinations thereof,

[0023] Optionally, two adjacent functional groups among R 1-1 、R 1-2 、R 1-3 、R 1-4 、R 2-1 、R 2-2 、R 3-1 、R 3-2 、R 4-1 and R 4-2 may combine with each other to form a ring structure.

[0024] The organometallic compound according to an exemplary embodiment of the present disclosure can be used as a dopant for a phosphorescent emission layer of an organic light-emitting diode, thereby reducing the operating voltage of the organic light-emitting diode and improving the efficiency and lifetime characteristics of the organic light-emitting diode.

[0025] The effects of the present disclosure are not limited to the above effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

[0026] It should be understood that the foregoing general description and the following detailed description of the present disclosure are both exemplary and explanatory, and are intended to provide further explanation of the inventive concept claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings, which are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this application, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0028] Figure 1 is a cross - sectional view schematically showing an organic light - emitting diode in which a light - emitting layer includes an organometallic compound according to an illustrative embodiment of the present disclosure.

[0029] Figure 2 is a cross - sectional view schematically showing an organic light - emitting diode having a tandem structure according to an illustrative embodiment of the present disclosure, the tandem structure having two light - emitting stacks and including an organometallic compound represented by Chemical Formula 1.

[0030] Figure 3 is a cross - sectional view schematically showing an organic light - emitting diode having a tandem structure according to an illustrative embodiment of the present disclosure, the tandem structure having three light - emitting stacks and including an organometallic compound represented by Chemical Formula 1.

[0031] Figure 4 is a cross - sectional view schematically showing an organic light - emitting display device including an organic light - emitting diode according to an illustrative embodiment of the present disclosure. Detailed Embodiments

[0032] Advantages and features of the present disclosure, and methods of achieving these advantages and features will become apparent by reference to exemplary embodiments described in detail hereinafter in conjunction with the accompanying drawings. However, the present disclosure is not limited to the exemplary embodiments disclosed hereinafter, but may be implemented in various different forms. Thus, the description of these exemplary embodiments is only for the purpose of making the present disclosure complete and informing those of ordinary skill in the art to which the present disclosure pertains of the full scope of the present disclosure, and the present disclosure is defined only by the scope of the claims.

[0033] Shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for describing the exemplary embodiments of the present disclosure are illustrative, and the present disclosure is not limited thereto. Herein, the same reference numerals refer to the same elements. In addition, for the sake of simplicity of description, descriptions and details of well - known steps and elements are omitted. Further, in the following detailed description of the present disclosure, many specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it should be understood that the present disclosure may be practiced without these specific details. In other cases, well - known methods, processes, components, and circuits are not described in detail so as not to unnecessarily obscure aspects of the present disclosure.

[0034] The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the present disclosure. As used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that when used in this specification, the terms “comprises,” “comprising,” “includes,” and “including” specify the presence of the stated features, integers, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, operations, elements, components, and / or portions thereof. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. When an expression such as “at least one” is used before a list of elements, it can modify the entire list of elements and can also modify individual elements of the list. In the interpretation of numerical values, an error or tolerance may occur even if not explicitly described.

[0035] In addition, it should also be understood that when a first element or layer is referred to as being “on” a second element or layer, the first element can be disposed directly on the second element or can be disposed indirectly on the second element with a third element or layer disposed between the first and second elements or layers. It should be understood that when an element or layer is referred to as being “connected to” or “coupled to” another element or layer, it can be directly connected to or coupled to the other element or layer, or there can be one or more intermediate elements or layers. In addition, it should also be understood that when an element or layer is referred to as being “between” two elements or layers, it can be the only element or layer between the two elements or layers, or there can also be one or more intermediate elements or layers.

[0036] In addition, as used herein, when a layer, film, region, plate, etc. is disposed “on” or “on top of” another layer, film, region, plate, etc., the former can be in direct contact with the latter, or another layer, film, region, plate, etc. can be disposed between the former and the latter. As used herein, when a layer, film, region, plate, etc. is disposed directly “on” or “on top of” another layer, film, region, plate, etc., the former is in direct contact with the latter and no other layer, film, region, plate, etc. is disposed between the former and the latter. In addition, as used herein, when a layer, film, region, plate, etc. is disposed “under” or “beneath” another layer, film, region, plate, etc., the former can be in direct contact with the latter, or another layer, film, region, plate, etc. can be disposed between the former and the latter. As used herein, when a layer, film, region, plate, etc. is disposed directly “under” or “beneath” another layer, film, region, plate, etc., the former is in direct contact with the latter and no other layer, film, region, plate, etc. is disposed between the former and the latter.

[0037] In the description of temporal relationships, for example, the temporal precedence relationship between two events such as "after", "subsequently", "before", etc., unless it is specified as "immediately after", "immediately subsequently", or "immediately before", another event may occur between these two events.

[0038] It should be understood that although terms such as "first", "second", "third", etc. may be used herein to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Thus, without departing from the spirit and scope of the present disclosure, the first element, component, region, layer, or part described below may be referred to as the second element, component, region, layer, or part.

[0039] The features of the various embodiments of the present disclosure may be partially or fully combined with each other, and may be technically related or interoperable with each other. The exemplary embodiments of the present disclosure may be implemented independently of each other or implemented together in an associated relationship.

[0040] When interpreting a numerical value, unless there is a separate and clear description, the value is interpreted as including the error range.

[0041] Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the inventive concept belongs. It should also be understood that terms such as those defined in a common dictionary should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and will not be interpreted as idealized or overly formal meanings unless explicitly defined herein.

[0042] As used herein, the phrase "adjacent functional groups combine with each other to form a ring structure" means that adjacent functional groups can combine with each other to form a substituted or unsubstituted alicyclic structure (cycloalkyl), a substituted or unsubstituted aromatic ring structure (aryl), or a ring structure having both substituted or unsubstituted alicyclic and aromatic rings (alkylaryl or arylalkyl). For a specific functional group, the phrase "adjacent functional groups" may refer to a functional group that substitutes an atom directly connected to the atom substituted by the specific functional group, the functional group that is spatially closest to the specific functional group, or a functional group that substitutes the atom substituted by the specific functional group. For example, two functional groups in the ortho position of a substituted benzene ring structure and two functional groups on the same carbon of a substituted alicyclic ring may be interpreted as "adjacent functional groups".

[0043] As used herein, unless otherwise specified, the term "substituted" means that the designated group or moiety bears one or more substituents. The term "unsubstituted" means that the designated group has no substituents.

[0044] As used herein and unless otherwise indicated, the term "substituent" refers to a non-hydrogen moiety such as deuterium, hydroxyl, halogen (e.g., fluorine, chlorine or bromine), carboxyl, formamido, imino, alkanoyl, cyano, cyanomethyl, nitro, amino, alkyl, alkenyl, alkynyl, cycloalkyl, arylalkyl, aryl, heterocyclic, heteroaryl, hydroxyl, alkoxy, alkoxycarbonyl, monoalkylaminosulfinyl, dialkylaminosulfinyl, monoalkylaminosulfonyl, dialkylaminosulfonyl, alkylsulfonamido, hydroxysulfonyloxy, alkoxysulfonyloxy, alkylsulfonyloxy, hydroxysulfonyl, alkoxysulfonyl, alkylsulfonylalkyl, monoalkylaminosulfonylalkyl, dialkylaminosulfonylalkyl, monoalkylaminosulfinylalkyl, dialkylaminosulfinylalkyl and the like.

[0045] As used herein and unless otherwise indicated, the term "alkyl" refers to a substituted or unsubstituted, saturated, straight-chain or branched-chain hydrocarbon radical. Examples of alkyl include, but are not limited to, C1-C15 straight-chain, branched-chain or cyclic alkyls such as methyl, ethyl, propyl, isopropyl, cyclopropyl, 2-methyl-1-propyl, 2-methyl-2-propyl, 2-methyl-1-butyl, 3-methyl-1-butyl, 2-methyl-3-butyl, 2,2-dimethyl-1-propyl, 2-methyl-1-pentyl, 3-methyl-1-pentyl, 4-methyl-1-pentyl, 2-methyl-2-pentyl, 3-methyl-2-pentyl, 4-methyl-2-pentyl, 2,2-dimethyl-1-butyl, 3,3-dimethyl-1-butyl, 2-ethyl-1-butyl, butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, pentyl, isopentyl, neopentyl, hexyl and cyclohexyl; and longer alkyls such as heptyl, octyl, nonyl and decyl. The alkyl may be unsubstituted or substituted with one or two suitable substituents.

[0046] As used herein and unless otherwise indicated, the term "cycloalkyl" refers to a monocyclic or polycyclic saturated ring containing carbon and hydrogen atoms and having no carbon-carbon multiple bonds. The cycloalkyl may be unsubstituted or substituted. Examples of cycloalkyl include, but are not limited to, (C3-C7) cycloalkyls including cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl, and saturated cyclic and bicyclic terpenes. The cycloalkyl may be unsubstituted or substituted. Preferably, the cycloalkyl is monocyclic or bicyclic.

[0047] As used herein and unless otherwise indicated, the term "aryl" refers to a monocyclic or polycyclic conjugated ring structure known in the art. Examples of suitable aryls or aromatic rings include, but are not limited to, phenyl, tolyl, anthryl, fluorenyl, indenyl, azulenyl and naphthyl. The aryl may be unsubstituted or substituted with one or two suitable substituents.

[0048] As used herein, unless otherwise specified, the term "substituted aryl" includes aryl optionally substituted with one or more of the following functional groups: such as halogen, alkyl, haloalkyl (e.g., trifluoromethyl), alkoxy, haloalkoxy (e.g., difluoromethoxy), alkenyl, alkynyl, aryl, heteroaryl, aralkyl, aryloxy, aryloxyalkyl, aralkyloxy, alkoxycarbonyl, alkylcarbonyl, arylcarbonyl, arylalkenyl, aminocarbonylaryl, arylthio, arylsulfinyl, arylazo, heteroaralkyl, heteroarylalkenyl, heteroaryloxy, hydroxy, nitro, cyano, amino, substituted amino (wherein the amino includes 1 or 2 substituents (optionally a substituted alkyl, aryl or any other substituent described herein)), mercapto, alkylthio, arylthio, heteroarylthio, arylthioalkyl, alkoxyarylthio, alkylaminocarbonyl, arylaminocarbonyl, aminocarbonyl, alkylcarbonyloxy, arylcarbonyloxy, alkylcarbonylamino, arylcarbonylamino, arylsulfinyl, arylsulfinylalkyl, arylsulfonylamino, or arylsulfonylaminocarbonyl, and / or any alkyl substituent described herein.

[0049] As used herein, unless otherwise specified, the term "heteroaryl" as used alone or as part of another group herein refers to a 5- to 7-membered aromatic ring including 1, 2, 3 or 4 heteroatoms (such as nitrogen, oxygen or sulfur), and such rings fused to an aryl, cycloalkyl, heteroaryl or heterocycloalkyl ring (e.g., benzothienyl, indolyl), and includes possible N-oxides. "Substituted heteroaryl" includes heteroaryl optionally substituted with 1 to 4 substituents (such as the substituents included in the definitions of "substituted alkyl" and "substituted cycloalkyl" above). Substituted heteroaryl also includes fused heteroaryl, which includes, for example, quinoline, isoquinoline, indole, isoindole, carbazole, acridine, benzimidazole, benzofuran, isobenzofuran, benzothiophene, phenanthroline, purine and the like.

[0050] Hereinafter, the structures and preparation examples of organometallic compounds according to the present disclosure and organic light-emitting diodes including the organometallic compounds will be described.

[0051] Conventionally, organometallic compounds have been used as dopants in the light-emitting layer of organic light-emitting diodes. For example, 2-phenylpyridine and 2-phenylquinoline in which a fused ring is introduced into the pyridine moiety of the 2-phenylpyridine structure are known as the main ligand structures of organometallic compounds. However, conventional light-emitting dopants have limitations in improving the efficiency and lifetime of organic light-emitting diodes. Therefore, it is necessary to develop a new light-emitting doping material. Accordingly, the inventors of the present disclosure have obtained a light-emitting doping material capable of further improving the efficiency and lifetime of organic light-emitting diodes, thereby completing the present disclosure.

[0052] Specifically, the organometallic compound according to an embodiment of the present disclosure can be represented by the following Chemical Formula 1. In L which is the main ligand of Chemical Formula 1 A a condensed ring structure of thiophene having a sulfur (S) atom is introduced into the ring connected to carbon (C) among the two rings connected to Ir (iridium) as the central coordination metal. In addition, based on the connection position and orientation of the thiophene condensed ring, the organometallic compound can be represented by one selected from the following Chemical Formulas 2-1 to 2-6. The inventors of the present disclosure found through experiments that when the organometallic compound represented by Chemical Formula 1 is used as a doping material for the phosphorescent light-emitting layer of an organic light-emitting diode, the luminous efficiency and lifespan of the organic light-emitting diode are improved, and its operating voltage is reduced, thus completing the present disclosure:

[0053] Ir(L A ) m (L B ) n (Chemical Formula 1)

[0054] Wherein in Chemical Formula 1,

[0055] L A can be represented by one selected from the group consisting of the following Chemical Formulas 2-1 to 2-6,

[0056] L B can be a bidentate ligand represented by the following Chemical Formula 3,

[0057] m can be 1, 2, or 3, n can be 0, 1, or 2, and the sum of m and n can be 3,

[0058]

[0059]

[0060] Wherein in each of Chemical Formulas 2-1 to 2-6,

[0061] X can represent one selected from the group consisting of -CH 2 -, oxygen, -NH-, and sulfur,

[0062] R 1-1 、R 1-2 、R 1-3 、R 1-4 、R 2-1 、R 2-2 、R 3-1 、R 3-2 、R 4-1 and R 4-2Each of them can independently represent one selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, aralkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, thioalkyl, sulfinyl, sulfonyl, phosphino and combinations thereof.

[0063] Optionally, R 1-1 , R 1-2 , R 1-3 , R 1-4 , R 2-1 , R 2-2 , R 3-1 , R 3-2 , R 4-1 and R 4-2 two adjacent functional groups among them can combine with each other to form a ring structure.

[0064] In the organometallic compound according to an embodiment of the present disclosure, the auxiliary ligand bonded to the central coordinating metal can be a bidentate ligand. The bidentate ligand can contain an electron donor, thereby increasing the amount of metal-to-ligand charge transfer (MLCT), so that the organic light-emitting diode exhibits improved light-emitting characteristics, such as high luminous efficiency and high external quantum efficiency.

[0065] The preferred auxiliary ligand according to the present disclosure can be a bidentate ligand represented by Chemical Formula 3. Chemical Formula 3 can be selected from one of the following Chemical Formula 4 and Chemical Formula 5:

[0066]

[0067] Wherein in Chemical Formula 4, R 5-1 , R 5-2 , R 5-3 , R 5-4 , R 6-1 , R 6-2 , R 6-3 and R 6-4 each of them can independently represent one selected from the group consisting of hydrogen, deuterium, C1-C5 straight-chain alkyl and C1-C5 branched-chain alkyl, and optionally, R 5-1 , R 5-2 , R 5-3 , R 5-4 , R 6-1 , R 6-2 , R 6-3 and R 6-4 two adjacent functional groups among them can combine with each other to form a ring structure,

[0068] Wherein in Chemical Formula 5, R 7 , R 8 and R9 Each of which may independently represent one selected from the group consisting of hydrogen, deuterium, C1-C5 straight-chain alkyl groups, and C1-C5 branched-chain alkyl groups, and optionally, R 7 , R 8 and R 9 Two adjacent functional groups among them may combine with each other to form a ring structure,

[0069] wherein the C1-C5 straight-chain alkyl group or the C1-C5 branched-chain alkyl group may be substituted with at least one selected from the group consisting of deuterium and halogen elements.

[0070] The organometallic compound according to an embodiment of the present disclosure may have a heteroleptic or homoleptic structure. For example, the organometallic compound according to an exemplary embodiment of the present disclosure may have: a heteroleptic structure, wherein in Chemical Formula 1, m is 1 and n is 2; or a heteroleptic structure, wherein in Chemical Formula 1, m is 2 and n is 1; or a homoleptic structure, wherein in Chemical Formula 1, m is 3 and n is 0.

[0071] Specific examples of the compound represented by Chemical Formula 1 of the present disclosure may include one selected from the group consisting of the following Compounds 1 to 540. However, the specific examples of the compound represented by Chemical Formula 1 of the present disclosure are not limited thereto, as long as the definition of Chemical Formula 1 above is satisfied:

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085]

[0086] According to one embodiment of the present disclosure, the organometallic compound represented by Chemical Formula 1 of the present disclosure can be used as a dopant material for achieving red phosphorescence or green phosphorescence, and preferably, as a dopant material for achieving green phosphorescence.

[0087] Referring to Figure 1 , according to one embodiment of the present disclosure, an organic light emitting diode 100 can be provided, which includes: a first electrode 110; a second electrode 120 facing the first electrode 110; and an organic layer 130 disposed between the first electrode 110 and the second electrode 120. The organic layer 130 may include a light emitting layer 160, and the light emitting layer 160 may include a host material 160' and a dopant 160". The dopant 160" may include the organometallic compound represented by Chemical Formula 1. In addition, in the organic light emitting diode 100, the organic layer 130 disposed between the first electrode 110 and the second electrode 120 can be formed by sequentially stacking a hole injection layer 140 (HIL), a hole transport layer 150 (HTL), a light emitting layer 160 (EML), an electron transport layer 170 (ETL), and an electron injection layer 180 (EIL) on the first electrode 110. The second electrode 120 can be formed on the electron injection layer 180, and a protective layer (not shown) can be formed on the second electrode 120.

[0088] In addition, although not shown in Figure 1 , a hole transport auxiliary layer can be further added between the hole transport layer 150 and the light emitting layer 160. The hole transport auxiliary layer may contain a compound having good hole transport characteristics, and can reduce the difference between the HOMO energy levels of the hole transport layer 150 and the light emitting layer 160 in order to adjust the hole injection characteristics. Therefore, the hole accumulation at the interface between the hole transport auxiliary layer and the light emitting layer 160 can be reduced, thereby reducing the quenching phenomenon in which excitons disappear at the interface due to polarons. Therefore, the deterioration of the device can be reduced and the device can be stabilized, thereby improving its efficiency and lifespan.

[0089] The first electrode 110 can be used as the positive electrode, and may include ITO, IZO, tin oxide, or zinc oxide as a conductive material having a relatively large work function value. However, the present disclosure is not limited thereto.

[0090] The second electrode 120 can be used as the negative electrode, and may include Al, Mg, Ca, or Ag, or an alloy or combination thereof as a conductive material having a relatively small work function value. However, the present disclosure is not limited thereto.

[0091] The hole injection layer 140 may be located between the first electrode 110 and the hole transport layer 150. The hole injection layer 140 may have a function of improving the interfacial characteristics between the first electrode 110 and the hole transport layer 150, and may be selected from materials having appropriate conductivity. The hole injection layer 140 may include a compound selected from the group consisting of N1-phenyl-N4,N4-bis(4-(phenyl(tolyl)amino)phenyl)-N1-(tolyl)benzene-1,4-diamine (MTDATA), copper(II) phthalocyanine (CuPc), tris(4-carbazol-9-ylphenyl)amine (TCTA), 1,4,5,8,9,11-hexaazatriphenylenehexanitrile (HATCN), 1,3,5-tris[4-(diphenylamino)phenyl]benzene (TDAPB), poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT / PSS), and N1,N1'-([1,1'-biphenyl]-4,4'-diyl)bis(N1,N4,N4-triphenylbenzene-1,4-diamine). Preferably, the hole injection layer 140 may include N1,N1'-([1,1'-biphenyl]-4,4'-diyl)bis(N1,N4,N4-triphenylbenzene-1,4-diamine). However, the present disclosure is not limited thereto.

[0092] The hole transport layer 150 may be located near the light-emitting layer 160 and between the first electrode 110 and the light-emitting layer 160. The material of the hole transport layer 150 may include at least one compound selected from the group consisting of N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD), N,N'-di(1-naphthyl)-N,N'-biphenyl-(1,1'-biphenyl)-4,4'-diamine (NPB), 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP), N-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluorene-2-amine, N-(biphenyl-4-yl)-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)biphenyl)-4-amine, and the like. Preferably, the material of the hole transport layer 150 may include NPB. However, the present disclosure is not limited thereto.

[0093] According to the present disclosure, the light-emitting layer 160 may be formed by doping a host material 160' with an organometallic compound represented by Chemical Formula 1 as a dopant 160" to improve the light-emitting efficiency of the diode 100. The dopant 160" may be used as a green or red light-emitting material, and preferably as a green phosphorescent material.

[0094] Based on the total weight of the host material 160', the doping concentration of the dopant 160" according to the exemplary embodiments of the present disclosure can be adjusted within the range of 1 wt% to 30 wt%. However, the present disclosure is not limited thereto. For example, the doping concentration can be within the range of 2 wt% to 20 wt%, such as 3 wt% to 15 wt%, such as 5 wt% to 10 wt%, such as 3 wt% to 8 wt%, such as 2 wt% to 7 wt%, such as 5 wt% to 7 wt%, or such as 5 wt% to 6 wt%.

[0095] The light-emitting layer 160 according to the exemplary embodiments of the present disclosure includes a host material 160' known in the art and capable of achieving the effects of the present disclosure, while the layer 160 includes an organometallic compound represented by Chemical Formula 1 as a dopant 160". For example, according to the present disclosure, the host material 160' may include a compound containing a carbazole group, and may preferably include a host material selected from the group consisting of CBP (4,4'-bis(N-carbazolyl)-1,1'-biphenyl), mCP (1,3-bis(carbazol-9-yl)), and the like. However, the present disclosure is not limited thereto.

[0096] In addition, the electron transport layer 170 and the electron injection layer 180 may be sequentially stacked between the light-emitting layer 160 and the second electrode 120. The material of the electron transport layer 170 needs to have a high electron mobility so that electrons can be stably supplied to the light-emitting layer under smooth electron transport.

[0097] For example, the material of the electron transport layer 170 may be known in the art and may include at least one compound selected from the group consisting of: Alq3 (tris(8-hydroxyquinoline)aluminum), (lithium 8-hydroxyquinolinate) (Liq), (2-(4-biphenylyl))-5-(4-tert-butylphenyl)-1,3,4-oxadiazole) (PBD), (3-(4-biphenyl)4-phenyl-5-tert-butylphenyl-1,2,4-triazole) (TAZ), spiro-PBD, (bis(2-methyl-8-quinolinolate)-4-(phenylphenol)aluminum) (BAlq), bis(2-methyl-8-hydroxyquinoline)(triphenylsilyloxy)aluminum (SAlq), (2,2',2-(1,3,5-benzenetriyl)-tris(1-phenyl-1-H-benzoimidazole) (TPBi), oxadiazole, triazole, phenanthroline, benzoxazole, benzothiazole, and 2-(4-(9,10-di(naphthalen-2-yl)anthracen-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole. Preferably, the material of the electron transport layer 170 may include 2-(4-(9,10-di(naphthalen-2-yl)anthracen-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole. However, the present disclosure is not limited thereto.

[0098] The electron injection layer 180 is used to facilitate electron injection. The material of the electron injection layer can be known in the art and includes at least one compound selected from the group consisting of Alq3 (aluminum tris(8-hydroxyquinoline)), PBD, TAZ, spiro-PBD, BAlq, SAlq, etc. However, the present disclosure is not limited thereto. Alternatively, the electron injection layer 180 can be made of a metal compound. The metal compound can include, for example, one or more selected from the group consisting of Liq, LiF, NaF, KF, RbF, CsF, FrF, BeF 2 , MgF 2 , CaF 2 , SrF 2 , BaF 2 and RaF 2 . However, the present disclosure is not limited thereto.

[0099] The organic light-emitting diode according to an exemplary embodiment of the present disclosure can be implemented as a white light-emitting diode having a tandem structure. The tandem organic light-emitting diode according to an illustrative embodiment of the present disclosure can be formed in a structure in which adjacent light-emitting stacks in two or more light-emitting stacks are connected to each other via a charge generation layer (CGL). The organic light-emitting diode can include at least two light-emitting stacks disposed on a substrate, wherein each of the at least two light-emitting stacks includes a first electrode and a second electrode facing each other, and a light-emitting layer disposed between the first electrode and the second electrode to emit light in a specific wavelength band. The plurality of light-emitting stacks can emit light of the same color or different colors. In addition, one or more light-emitting layers can be included in one light-emitting stack, and the plurality of light-emitting layers can emit light of the same color or different colors.

[0100] In this case, the light-emitting layer included in at least one of the plurality of light-emitting stacks can contain an organometallic compound represented by Chemical Formula 1 according to the present disclosure as a dopant. Adjacent light-emitting stacks in the plurality of light-emitting stacks in the tandem structure can be connected to each other via a charge generation layer CGL including an N-type charge generation layer and a P-type charge generation layer.

[0101] Figure 2 and Figure 3 are cross-sectional views schematically showing an organic light-emitting diode in a tandem structure having two light-emitting stacks and an organic light-emitting diode in a tandem structure having three light-emitting stacks, respectively, according to some embodiments of the present disclosure.

[0102] As Figure 2As shown, the organic light emitting diode 100 according to an exemplary embodiment of the present disclosure includes a first electrode 110 and a second electrode 120 facing each other, and an organic layer 230 located between the first electrode 110 and the second electrode 120. The organic layer 230 may be located between the first electrode 110 and the second electrode 120 and may include a first light emitting stack ST1 including a first light emitting layer 261, a second light emitting stack ST2 located between the first light emitting stack ST1 and the second electrode 120 and including a second light emitting layer 262, and a charge generation layer CGL located between the first light emitting stack ST1 and the second light emitting stack ST2. The charge generation layer CGL may include an N-type charge generation layer 291 and a P-type charge generation layer 292. At least one of the first light emitting layer 261 and the second light emitting layer 262 may include an organometallic compound represented by Chemical Formula 1 according to the present disclosure as a dopant. For example, as Figure 2 shown, the second light emitting layer 262 of the second light emitting stack ST2 may include a host material 262' and a dopant 262" including an organometallic compound represented by Chemical Formula 1 doped therein. Although Figure 2 not shown, in addition to each of the first light emitting layer 261 and the second light emitting layer 262, each of the first light emitting stack ST1 and the second light emitting stack ST2 may further include an additional light emitting layer. In one embodiment, the first HTL 251 and the second HTL 252 may have a structure and material similar to or the same as those of Figure 1 the HTL 150. In one embodiment, the first ETL 271 and the second ETL 272 may have a structure and material similar to or the same as those of Figure 1 the ETL 170.

[0103] As Figure 3As shown, the organic light emitting diode 100 according to an exemplary embodiment of the present disclosure includes a first electrode 110 and a second electrode 120 facing each other, and an organic layer 330 disposed between the first electrode 110 and the second electrode 120. The organic layer 330 may be disposed between the first electrode 110 and the second electrode 120 and may include a first light emitting stack ST1 including a first light emitting layer 261, a second light emitting stack ST2 including a second light emitting layer 262, a third light emitting stack ST3 including a third light emitting layer 263, a first charge generation layer CGL1 disposed between the first light emitting stack ST1 and the second light emitting stack ST2, and a second charge generation layer CGL2 disposed between the second light emitting stack ST2 and the third light emitting stack ST3. The first charge generation layer CGL1 may include an N-type charge generation layer 291 and a P-type charge generation layer 292. The second charge generation layer CGL2 may include an N-type charge generation layer 293 and a P-type charge generation layer 294. At least one of the first light emitting layer 261, the second light emitting layer 262, and the third light emitting layer 263 may include an organometallic compound represented by Chemical Formula 1 according to the present disclosure as a dopant. For example, as Figure 3 shown, the second light emitting layer 262 of the second light emitting stack ST2 may include a host material 262' and a dopant 262" made of an organometallic compound represented by Chemical Formula 1 doped therein. Although Figure 3 not shown in, in addition to each of the first light emitting layer 261, the second light emitting layer 262, and the third light emitting layer 263, each of the first light emitting stack ST1, the second light emitting stack ST2, and the third light emitting stack ST3 may further include an additional light emitting layer. In one embodiment, the first HTL 251, the second HTL 252, and the third HTL 253 may have a structure and material similar to or the same as that of Figure 1 the HTL 150. In one embodiment, the first ETL 271, the second ETL 272, and the third ETL 273 may have a structure and material similar to or the same as that of Figure 1 the ETL 170.

[0104] In addition, the organic light emitting diode according to an exemplary embodiment of the present disclosure may include a tandem structure in which four or more light emitting stacks and three or more charge generation layers are disposed between the first electrode and the second electrode.

[0105] The organic light emitting diode according to an exemplary embodiment of the present disclosure can be used as a light emitting element of each of an organic light emitting display device and a lighting device. In one embodiment, Figure 4 is a cross-sectional view schematically showing an organic light emitting display device including an organic light emitting diode according to some embodiments of the present disclosure as its light emitting element.

[0106] AsFigure 4 As shown, the organic light-emitting display device 3000 includes a substrate 3010, an organic light-emitting diode 4000, and a encapsulation film 3900 covering the organic light-emitting diode 4000. A driving thin-film transistor Td as a driving element and the organic light-emitting diode 4000 connected to the driving thin-film transistor Td are located on the substrate 3010.

[0107] Although not explicitly shown in Figure 4 , a gate line and a data line that cross each other to define a pixel region, a power supply line that extends parallel to and is spaced apart from one of the gate line and the data line, a switching thin-film transistor connected to the gate line and the data line, and a storage capacitor connected to one electrode of the thin-film transistor and the power supply line are further formed on the substrate 3010.

[0108] The driving thin-film transistor Td is connected to the switching thin-film transistor and includes a semiconductor layer 3100, a gate 3300, a source 3520, and a drain 3540.

[0109] The semiconductor layer 3100 may be formed on the substrate 3010 and may be made of an oxide semiconductor material or polysilicon. When the semiconductor layer 3100 is made of an oxide semiconductor material, a light-shielding pattern (not shown) may be formed under the semiconductor layer 3100. The light-shielding pattern prevents light from entering the semiconductor layer 3100 to prevent the semiconductor layer 3100 from deteriorating due to light. Alternatively, the semiconductor layer 3100 may be made of polysilicon. In this case, both edges of the semiconductor layer 3100 may be doped with impurities.

[0110] A gate insulating layer 3200 made of an insulating material is formed on the entire surface of the substrate 3010 and on the semiconductor layer 3100. The gate insulating layer 3200 may be made of an inorganic insulating material such as silicon oxide or silicon nitride.

[0111] A gate 3300 made of a conductive material such as metal is formed on the gate insulating layer 3200 and corresponds to the center of the semiconductor layer 3100. The gate 3300 is connected to the switching thin-film transistor.

[0112] An interlayer insulating layer 3400 made of an insulating material is formed on the entire surface of the substrate 3010 and on the gate 3300. The interlayer insulating layer 3400 may be made of an inorganic insulating material such as silicon oxide or silicon nitride, or an organic insulating material such as benzocyclobutene or optical acrylic.

[0113] The interlayer insulating layer 3400 has a first semiconductor layer contact hole 3420 and a second semiconductor layer contact hole 3440 defined therein to respectively expose opposite sides of the semiconductor layer 3100. The first semiconductor layer contact hole 3420 and the second semiconductor layer contact hole 3440 are respectively located on opposite sides of the gate 3300 and are spaced apart from the gate 3300.

[0114] A source electrode 3520 and a drain electrode 3540 made of a conductive material such as metal are formed on the interlayer insulating layer 3400. The source electrode 3520 and the drain electrode 3540 are located around the gate 3300, are spaced apart from each other, and each contact opposite sides of the semiconductor layer 3100 through the first semiconductor layer contact hole 3420 and the second semiconductor layer contact hole 3440 respectively. The source electrode 3520 is connected to a power supply line (not shown).

[0115] The semiconductor layer 3100, the gate 3300, the source electrode 3520, and the drain electrode 3540 constitute a driving thin film transistor Td. The driving thin film transistor Td has a coplanar structure in which the gate 3300, the source electrode 3520, and the drain electrode 3540 are located on top of the semiconductor layer 3100.

[0116] Alternatively, the driving thin film transistor Td may have an inverted staggered structure in which the gate is disposed below the semiconductor layer, while the source and drain are disposed above the semiconductor layer. In this case, the semiconductor layer may be made of amorphous silicon. In one example, a switching thin film transistor (not shown) may have substantially the same structure as the driving thin film transistor (Td).

[0117] In one example, the organic light emitting display device 3000 may include a color filter 3600 that absorbs light generated from the electroluminescent element (light emitting diode) 4000. For example, the color filter 3600 may absorb red (R), green (G), blue (B), and white (W) light. In this case, red, green, and blue color filter patterns that absorb light may be respectively formed in different pixel regions. Each of these color filter patterns may be arranged to overlap with each organic layer 4300 of the organic light emitting diode 4000 to emit light corresponding to the wavelength band of each color filter. Employing the color filter 3600 can enable the organic light emitting display device 3000 to achieve full color.

[0118] For example, when the organic light emitting display device 3000 is a bottom emission type, the color filter 3600 that absorbs light may be disposed on a part of the interlayer insulating layer 3400 corresponding to the organic light emitting diode 4000. In an alternative embodiment, when the organic light emitting display device 3000 is a top emission type, the color filter may be disposed on top of the organic light emitting diode 4000, i.e., on top of the second electrode 4200. For example, the color filter 3600 may be formed to have a thickness of 2 - 5 μm.

[0119] In one example, a protective layer 3700 is formed to cover the driving thin film transistor Td, and the protective layer 3700 has a drain contact hole 3720 defined therein that exposes the drain 3540 of the driving thin film transistor Td.

[0120] On the protective layer 3700, each first electrode 4100 connected to the drain 3540 of the driving thin film transistor Td via the drain contact hole 3720 is formed in each pixel region, respectively.

[0121] The first electrode 4100 can be used as a positive electrode (anode), and can be made of a conductive material having a relatively large work function value. For example, the first electrode 4100 can be made of a transparent conductive material such as ITO, IZO, or ZnO.

[0122] In one example, when the organic light-emitting display device 3000 is a top-emitting type, a reflective electrode or a reflective layer can be further formed under the first electrode 4100. For example, the reflective electrode or the reflective layer can include at least one of aluminum (Al), silver (Ag), nickel (Ni), or an aluminum-palladium-copper (APC) alloy.

[0123] A bank layer 3800 covering the edge of the first electrode 4100 is formed on the protective layer 3700. The bank layer 3800 exposes the center of the first electrode 4100 corresponding to the pixel region.

[0124] An organic layer 4300 is formed on the first electrode 4100. As needed, the organic light-emitting diode 4000 can have a series structure. Regarding the series structure, reference can be made to Figures 2 to 4 which shows some embodiments of the present disclosure and the above description.

[0125] A second electrode 4200 is formed on the substrate 3010 on which the organic layer 4300 has been formed. The second electrode 4200 is disposed on the entire surface of the display region, and is made of a conductive material having a relatively small work function value, and the second electrode 4200 can be used as a negative electrode (cathode). For example, the second electrode 4200 can be made of one of aluminum (Al), magnesium (Mg), and an aluminum-magnesium alloy (Al-Mg).

[0126] The first electrode 4100, the organic layer 4300, and the second electrode 4200 constitute the organic light-emitting diode 4000.

[0127] A encapsulation film 3900 is formed on the second electrode 4200 to prevent external moisture from penetrating into the organic light-emitting diode 4000. Although not explicitly shown in Figure 4 the encapsulation film 3900 can have a three-layer structure in which an inorganic layer, an organic layer, and an inorganic layer are sequentially stacked. However, the present disclosure is not limited thereto.

[0128] In the following, preparation examples and examples of the present disclosure will be described. However, the following examples are merely examples of the present disclosure. The present disclosure is not limited thereto.

[0129] Preparation Example - Preparation of Ligand

[0130] (1) Preparation of Ligand Compound A

[0131] Step 1) Preparation of Ligand Compound A-2

[0132]

[0133] Under a nitrogen atmosphere, compound SM-1 (4.58 g, 20 mmol), compound SM-2 (3.67 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3 (0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated to reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then subjected to column chromatography separation with ethyl acetate and hexane to obtain compound A-2 (4.72 g, 82%).

[0134] Step 2) Preparation of Ligand Compound A-1

[0135]

[0136] Under a nitrogen atmosphere, compound A-2 (5.76 g, 20 mmol), compound SM-3 (4.28 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3 (0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated to reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then subjected to column chromatography separation with ethyl acetate and hexane to obtain compound A-1 (6.04 g, 80%).

[0137] Step 3) Preparation of Ligand Compound A

[0138]

[0139] Under a nitrogen atmosphere, compound A-1 (7.55 g, 20 mmol) was dissolved in 80 mL of acetic acid and 25 mL of THF in a 250 mL round-bottom flask. Then, tert-butyl nitrite (5 mL, 38 mmol) was added dropwise to the mixed solution at 0 °C, and the mixed solution was stirred. After stirring at 0 °C for 4 hours, the temperature was raised to room temperature. The organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then separated by column chromatography using dichloromethane and hexane to obtain compound A (4.58 g, 64%).

[0140] (2) Preparation of ligand compound B

[0141] Step 1) Preparation of ligand compound B-2

[0142]

[0143] Under a nitrogen atmosphere, compound A-2 (5.76 g, 20 mmol), compound SM-4 (4.56 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3 (0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated to reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature. The organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then separated by column chromatography using ethyl acetate and hexane to obtain compound B-2 (6.50 g, 83%).

[0144] Step 2) Preparation of ligand compound B-1

[0145]

[0146] Under a nitrogen atmosphere, compound B-2 (7.83 g, 20 mmol) was dissolved in 80 mL of acetic acid and 25 mL of THF in a 250 mL round-bottom flask. Then, tert-butyl nitrite (5 mL, 38 mmol) was added dropwise to the mixed solution at 0 °C, and the mixed solution was stirred. After stirring for 4 hours at 0 °C, the temperature was raised to room temperature, the organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then column chromatographed with dichloromethane and hexane to obtain compound B-1 (5.05 g, 68%).

[0147] Step 3) Preparation of ligand compound B

[0148]

[0149] Under a nitrogen atmosphere, compound B-1 (7.43 g, 20 mmol) and sodium tert-butoxide (4 mL, 40 mmol) were added to 100 mL of DMSO-d 6 in a 250 mL round-bottom flask. Then, the mixed solution was heated and stirred at 135 °C for 48 hours. After the reaction was completed, the reaction vessel was cooled to room temperature, the organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and column chromatographed with ethyl acetate and dichloromethane to obtain compound B (6.13 g, 82%).

[0150] (3) Preparation of ligand compound C

[0151] Step 1) Preparation of ligand compound C-2

[0152]

[0153] Under a nitrogen atmosphere, compound SM-5 (4.86 g, 20 mmol), compound SM-2 (3.67 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3 (0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated to reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then column chromatographed with ethyl acetate and hexane to obtain compound C-2 (4.77 g, 79%).

[0154] Step 2) Preparation of Ligand Compound C-1

[0155]

[0156] Under a nitrogen atmosphere, compound C-2 (6.04 g, 20 mmol), compound SM-3 (4.28 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3 (0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated to reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then subjected to column chromatography using ethyl acetate and hexane to obtain compound C-1 (6.58 g, 84%).

[0157] Step 3) Preparation of Ligand Compound C

[0158]

[0159] Under a nitrogen atmosphere, compound C-1 (7.83 g, 20 mmol) was dissolved in 80 mL of acetic acid and 25 mL of THF in a 250 mL round-bottom flask. Then, tert-butyl nitrite (5 mL, 38 mmol) was added dropwise to the mixed solution at 0 °C, and the mixed solution was stirred. After stirring for 4 hours at 0 °C, the temperature was raised to room temperature, and the organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then subjected to column chromatography using dichloromethane and hexane to obtain compound C (4.83 g, 65%).

[0160] (4) Preparation of Ligand Compound D

[0161] Step 1) Preparation of Ligand Compound D-2

[0162]

[0163] Under a nitrogen atmosphere, compound C-2 (6.04 g, 20 mmol), compound SM-4 (4.56 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3(0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated to reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then separated by column chromatography using ethyl acetate and hexane to obtain compound D-2 (6.81 g, 84%).

[0164] Step 2) Preparation of ligand compound D-1

[0165]

[0166] Under a nitrogen atmosphere, compound D-2 (8.11 g, 20 mmol) was dissolved in 80 mL of acetic acid and 25 mL of THF in a 250 mL round-bottom flask. Then, tert-butyl nitrite (5 mL, 38 mmol) was added dropwise to the mixed solution at 0 °C, and the mixed solution was stirred. After stirring for 4 hours at 0 °C, the temperature was raised to room temperature, and the organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then separated by column chromatography using dichloromethane and hexane to obtain compound D-1 (6.32 g, 82%).

[0167] Step 3) Preparation of ligand compound D

[0168]

[0169] Under a nitrogen atmosphere, compound D-1 (7.71 g, 20 mmol) and sodium tert-butoxide (4 mL, 40 mmol) were added to 100 mL of DMSO-d 6 in a 250 mL round-bottom flask. Then, the mixed solution was heated at 135 °C and stirred for 48 hours. After the reaction was completed, the reaction vessel was cooled to room temperature, the organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and separated by column chromatography using ethyl acetate and dichloromethane to obtain compound D (5.43 g, 70%).

[0170] (5) Preparation of ligand compound E

[0171] Step 1) Preparation of ligand compound E-2

[0172]

[0173] Under a nitrogen atmosphere, compound SM-6 (4.58 g, 20 mmol), compound SM-2 (3.67 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3 (0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated to reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then subjected to column chromatography separation with ethyl acetate and hexane to obtain compound E-2 (4.90 g, 85%).

[0174] Step 2) Preparation of ligand compound E-1

[0175]

[0176] Under a nitrogen atmosphere, compound E-2 (5.76 g, 20 mmol), compound SM-3 (4.28 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3 (0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated to reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then subjected to column chromatography separation with ethyl acetate and hexane to obtain compound E-1 (6.42 g, 85%).

[0177] Step 3) Preparation of ligand compound E

[0178]

[0179] Under a nitrogen atmosphere, compound E-1 (7.55 g, 20 mmol) was dissolved in 80 mL of acetic acid and 25 mL of THF in a 250 mL round-bottom flask. Then, tert-butyl nitrite (5 mL, 38 mmol) was added dropwise to the mixed solution at 0 °C, and the mixed solution was stirred. After stirring for 4 hours at 0 °C, the temperature was raised to room temperature, and the organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then separated by column chromatography using dichloromethane and hexane to obtain compound E (4.86 g, 68%).

[0180] (6) Preparation of ligand compound F

[0181] Step 1) Preparation of ligand compound F-2

[0182]

[0183] Under a nitrogen atmosphere, compound E-2 (5.76 g, 20 mmol), compound SM-4 (4.56 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3 (0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated to reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then separated by column chromatography using ethyl acetate and hexane to obtain compound F-2 (6.34 g, 81%).

[0184] Step 2) Preparation of ligand compound F-1

[0185]

[0186] Under a nitrogen atmosphere, compound F-2 (7.83 g, 20 mmol) was dissolved in 80 mL of acetic acid and 25 mL of THF in a 250 mL round-bottom flask. Then, tert-butyl nitrite (5 mL, 38 mmol) was added dropwise to the mixed solution at 0 °C, and the mixed solution was stirred. After stirring for 4 hours at 0 °C, the temperature was raised to room temperature, and the organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then separated by column chromatography using dichloromethane and hexane to obtain compound F-1 (6.17 g, 83%).

[0187] Step 3) Preparation of ligand compound F

[0188]

[0189] Under a nitrogen atmosphere, compound F-1 (7.43 g, 20 mmol) and sodium tert-butoxide (4 mL, 40 mmol) were added to 100 mL of DMSO-d in a 250 mL round-bottom flask 6 and then the mixed solution was heated and stirred at 135 °C for 48 hours. After completion of the reaction, the reaction vessel was cooled to room temperature, the organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, the solution was filtered through a filter, and then concentrated under reduced pressure. Column chromatography was performed using ethyl acetate and dichloromethane to obtain compound F (5.01 g, 67%).

[0190] (7) Preparation of ligand compound G

[0191] Step 1) Preparation of ligand compound G-2

[0192]

[0193] Under a nitrogen atmosphere, compound SM-7 (4.86 g, 20 mmol), compound SM-2 (3.67 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3 (0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask, and then the mixed solution was heated to reflux and stirred for 12 hours. After completion of the reaction, the temperature was lowered to room temperature, the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, the solution was filtered through a filter, and then concentrated under reduced pressure. Then column chromatography was performed using ethyl acetate and hexane to obtain compound G-2 (4.83 g, 80%).

[0194] Step 2) Preparation of ligand compound G-1

[0195]

[0196] Under a nitrogen atmosphere, compound G-2 (6.04 g, 20 mmol), compound SM-3 (4.28 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3(0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated under reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then subjected to column chromatography separation with ethyl acetate and hexane to obtain compound G-1 (6.58 g, 84%).

[0197] Step 3) Preparation of ligand compound G

[0198]

[0199] Under a nitrogen atmosphere, compound G-1 (7.83 g, 20 mmol) was dissolved in 80 mL of acetic acid and 25 mL of THF in a 250 mL round-bottom flask. Then, tert-butyl nitrite (5 mL, 38 mmol) was added dropwise to the mixed solution at 0 °C, and the mixed solution was stirred. After stirring for 4 hours at 0 °C, the temperature was raised to room temperature, and the organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then subjected to column chromatography separation with dichloromethane and hexane to obtain compound G (4.76 g, 64%).

[0200] (8) Preparation of ligand compound H

[0201] Step 1) Preparation of ligand compound H-2

[0202]

[0203] Under a nitrogen atmosphere, compound G-2 (6.04 g, 20 mmol), compound SM-4 (4.56 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3 (0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated under reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then subjected to column chromatography separation with ethyl acetate and hexane to obtain compound H-2 (6.65 g, 82%).

[0204] Step 2) Preparation of ligand compound H-1

[0205]

[0206] Under a nitrogen atmosphere, compound H-2 (8.11 g, 20 mmol) was dissolved in 80 mL of acetic acid and 25 mL of THF in a 250 mL round-bottom flask. Then, tert-butyl nitrite (5 mL, 38 mmol) was added dropwise to the mixed solution at 0 °C, and the mixed solution was stirred. After stirring at 0 °C for 4 hours, the temperature was raised to room temperature, the organic layer was extracted with ethyl acetate, and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, the solution was filtered through a filter, then concentrated under reduced pressure, and then column chromatographed with dichloromethane and hexane to obtain compound H-1 (6.25 g, 81%).

[0207] Step 3) Preparation of ligand compound H

[0208]

[0209] Under a nitrogen atmosphere, compound H-1 (7.71 g, 20 mmol) and sodium tert-butoxide (4 mL, 40 mmol) were added to 100 mL of DMSO-d 6 in a 250 mL round-bottom flask. Then, the mixed solution was heated and stirred at 135 °C for 48 hours. After the reaction was completed, the reaction vessel was cooled to room temperature, the organic layer was extracted with ethyl acetate, and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, the solution was filtered through a filter, then concentrated under reduced pressure, and column chromatographed with ethyl acetate and dichloromethane to obtain compound H (5.19 g, 67%).

[0210] (9) Preparation of ligand compound I

[0211] Step 1) Preparation of ligand compound I-3

[0212]

[0213] Under a nitrogen atmosphere, compound SM-8 (4.58 g, 20 mmol), compound SM-2 (3.67 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3 (0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated to reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, the solution was filtered through a filter, then concentrated under reduced pressure, and then column chromatographed with ethyl acetate and hexane to obtain compound I-3 (4.67 g, 81%).

[0214] Step 2) Preparation of Ligand Compound I-2

[0215]

[0216] Under a nitrogen atmosphere, compound I-3 (5.76 g, 20 mmol), compound SM-4 (4.56 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3 (0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated to reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then subjected to column chromatography using ethyl acetate and hexane to obtain compound I-2 (6.42 g, 82%).

[0217] Step 3) Preparation of Ligand Compound I-1

[0218]

[0219] Under a nitrogen atmosphere, compound I-2 (7.83 g, 20 mmol) was dissolved in 80 mL of acetic acid and 25 mL of THF in a 250 mL round-bottom flask. Then, tert-butyl nitrite (5 mL, 38 mmol) was added dropwise to the mixed solution at 0 °C, and the mixed solution was stirred. After stirring for 4 hours at 0 °C, the temperature was raised to room temperature, and the organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then subjected to column chromatography using dichloromethane and hexane to obtain compound I-1 (5.80 g, 78%).

[0220] Step 4) Preparation of Ligand Compound I

[0221]

[0222] Under a nitrogen atmosphere, compound I-1 (7.43 g, 20 mmol) and sodium tert-butoxide (4 mL, 40 mmol) were added to 100 mL of DMSO-d 6Then, the mixed solution was heated and stirred at 135 °C for 48 hours. After the reaction was completed, the reaction vessel was cooled to room temperature, the organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, the solution was filtered through a filter, then concentrated under reduced pressure, and column chromatography was performed using ethyl acetate and dichloromethane to obtain Compound I (4.86 g, 65%).

[0223] (10) Preparation of Ligand Compound J

[0224] Step 1) Preparation of Ligand Compound J-3

[0225]

[0226] Under a nitrogen atmosphere, Compound SM-9 (4.86 g, 20 mmol), Compound SM-2 (3.67 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3 (0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated to reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, the solution was filtered through a filter, then concentrated under reduced pressure, and column chromatography was performed using ethyl acetate and hexane to obtain Compound J-3 (4.71 g, 78%).

[0227] Step 2) Preparation of Ligand Compound J-2

[0228]

[0229] Under a nitrogen atmosphere, Compound J-3 (6.04 g, 20 mmol), Compound SM-4 (4.56 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3 (0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated to reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, the solution was filtered through a filter, then concentrated under reduced pressure, and column chromatography was performed using ethyl acetate and hexane to obtain Compound J-2 (6.49 g, 80%).

[0230] Step 3) Preparation of Ligand Compound J-1

[0231]

[0232] Under a nitrogen atmosphere, compound J-2 (8.11 g, 20 mmol) was dissolved in 80 mL of acetic acid and 25 mL of THF in a 250 mL round-bottom flask. Then, tert-butyl nitrite (5 mL, 38 mmol) was added dropwise to the mixed solution at 0 °C, and the mixed solution was stirred. After stirring for 4 hours at 0 °C, the temperature was raised to room temperature, and the organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then subjected to column chromatography separation with dichloromethane and hexane to obtain compound J-1 (5.09 g, 66%).

[0233] Step 4) Preparation of Ligand Compound J

[0234]

[0235] Under a nitrogen atmosphere, compound J-1 (7.71 g, 20 mmol) and sodium tert-butoxide (4 mL, 40 mmol) were added to 100 mL of DMSO-d 6 in a 250 mL round-bottom flask. Then, the mixed solution was heated and stirred at 135 °C for 48 hours. After the reaction was completed, the reaction vessel was cooled to room temperature, and the organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and subjected to column chromatography separation with ethyl acetate and dichloromethane to obtain compound J (6.36 g, 82%).

[0236] (11) Preparation of Ligand Compound K

[0237] Step 1) Preparation of Ligand Compound K-3

[0238]

[0239] Under a nitrogen atmosphere, compound SM-10 (4.58 g, 20 mmol), compound SM-2 (3.67 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3(0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated under reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then separated by column chromatography with ethyl acetate and hexane to obtain compound K-3 (4.44 g, 77%).

[0240] Step 2) Preparation of ligand compound K-2

[0241]

[0242] Under a nitrogen atmosphere, compound K-3 (5.76 g, 20 mmol), compound SM-4 (4.56 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3 (0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated under reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then separated by column chromatography with ethyl acetate and hexane to obtain compound K-2 (6.26 g, 80%).

[0243] Step 3) Preparation of ligand compound K-1

[0244]

[0245] Under a nitrogen atmosphere, compound K-2 (7.83 g, 20 mmol) was dissolved in 80 mL of acetic acid and 25 mL of THF in a 250 mL round-bottom flask. Then, tert-butyl nitrite (5 mL, 38 mmol) was added dropwise to the mixed solution at 0 °C, and the mixed solution was stirred. After stirring at 0 °C for 4 hours, the temperature was raised to room temperature, and the organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then separated by column chromatography with dichloromethane and hexane to obtain compound K-1 (6.17 g, 83%).

[0246] Step 4) Preparation of ligand compound K

[0247]

[0248] Under a nitrogen atmosphere, compound K-1 (7.43 g, 20 mmol) and sodium tert-butoxide (4 mL, 40 mmol) were added to 100 mL of DMSO-d in a 250 mL round-bottom flask 6 , and then the mixed solution was heated and stirred at 135 °C for 48 hours. After the reaction was completed, the reaction vessel was cooled to room temperature, the organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and column chromatography was performed using ethyl acetate and dichloromethane to obtain compound K (5.08 g, 68%).

[0249] (12) Preparation of ligand compound L

[0250] Step 1) Preparation of ligand compound L-3

[0251]

[0252] Under a nitrogen atmosphere, compound SM-11 (4.86 g, 20 mmol), compound SM-2 (3.67 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3 (0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask, and then the mixed solution was heated to reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and column chromatography was performed using ethyl acetate and hexane to obtain compound L-3 (4.53 g, 75%).

[0253] Step 2) Preparation of ligand compound L-2

[0254]

[0255] Under a nitrogen atmosphere, compound L-3 (6.04 g, 20 mmol), compound SM-4 (4.56 g, 20 mmol), Pd(PPh 3 ) 4 (2.31 g, 2 mmol), P(t-Bu) 3(0.81 g, 4 mmol) and NaOtBu (7.68 g, 80 mmol) were dissolved in 200 mL of toluene in a 250 mL round-bottom flask. Then, the mixed solution was heated to reflux and stirred for 12 hours. After the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted with dichloromethane and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then subjected to column chromatography using ethyl acetate and hexane to obtain compound L-2 (6.33 g, 78%).

[0256] Step 3) Preparation of ligand compound L-1

[0257]

[0258] Under a nitrogen atmosphere, compound L-2 (8.11 g, 20 mmol) was dissolved in 80 mL of acetic acid and 25 mL of THF in a 250 mL round-bottom flask. Then, tert-butyl nitrite (5 mL, 38 mmol) was added dropwise to the mixed solution at 0 °C, and the mixed solution was stirred. After stirring for 4 hours at 0 °C, the temperature was raised to room temperature, and the organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and then subjected to column chromatography using dichloromethane and hexane to obtain compound L-1 (5.01 g, 65%).

[0259] Step 4) Preparation of ligand compound L

[0260]

[0261] Under a nitrogen atmosphere, compound L-1 (7.71 g, 20 mmol) and sodium tert-butoxide (4 mL, 40 mmol) were added to 100 mL of DMSO-d 6 in a 250 mL round-bottom flask. Then, the mixed solution was heated and stirred at 135 °C for 48 hours. After the reaction was completed, the reaction vessel was cooled to room temperature, and the organic layer was extracted with ethyl acetate and washed thoroughly with water. The water was removed with anhydrous magnesium sulfate, and the solution was filtered through a filter, then concentrated under reduced pressure, and subjected to column chromatography using ethyl acetate and dichloromethane to obtain compound L (6.51 g, 84%).

[0262] Preparation Example - Preparation of a precursor of an iridium compound (iridium precursor)

[0263] (1) Preparation of iridium precursor compound M'

[0264] Step 1) Preparation of compound MM

[0265]

[0266] Under a nitrogen atmosphere, compound M (3.38 g, 20 mmol) and IrCl 3 (2.39 g, 8.0 mmol) were dissolved in a mixed solution of ethoxyethanol: distilled water = 90 mL: 30 mL and added to a 250 mL round-bottom flask. The mixed solution was refluxed and stirred for 24 hours. After the reaction was completed, the temperature was lowered to room temperature, and the resulting solid was separated therefrom by filtration under reduced pressure. The solid was filtered using a filter and washed thoroughly with water and cold methanol, and filtered repeatedly under reduced pressure several times to obtain 4.24 g (94%) of the solid compound MM.

[0267] Step 2) Preparation of iridium precursor compound M'

[0268]

[0269] In a 250 mL round-bottom flask, compound MM (4.51 g, 4 mmol) and silver trifluoromethanesulfonate (AgOTf, 3.02 g, 12 mmol) were dissolved in dichloromethane and the mixed solution was stirred at room temperature for 24 hours. After the reaction was completed, the solid precipitate was removed by filtration through diatomaceous earth. The resulting filtrate was filtered through a filter and distilled under reduced pressure to obtain 5.34 g (90%) of the resulting solid compound M'.

[0270] (2) Preparation of iridium precursor compound B'

[0271] Step 1) Preparation of compound BB

[0272]

[0273] Under a nitrogen atmosphere, compound B (7.47 g, 20 mmol) and IrCl 3 (2.39 g, 8.0 mmol) were dissolved in a mixed solution of ethoxyethanol: distilled water = 90 mL: 30 mL and added to a 250 mL round-bottom flask. The mixed solution was heated to reflux and stirred for 24 hours. After the reaction was completed, the temperature was lowered to room temperature, and the resulting solid was separated therefrom by filtration under reduced pressure. The solid was filtered using a filter and washed thoroughly with water and cold methanol, and filtered repeatedly under reduced pressure several times to obtain 7.00 g (90%) of the solid compound BB.

[0274] Step 2) Preparation of iridium precursor compound B'

[0275]

[0276] In a 250 mL round-bottom flask, compound BB (7.78 g, 4 mmol) and silver trifluoromethanesulfonate (AgOTf, 3.02 g, 12 mmol) were dissolved in dichloromethane and the mixed solution was stirred at room temperature for 24 hours. After the reaction was completed, the solid precipitate was removed by filtration through diatomaceous earth. The resulting filtrate was filtered through a filter and distilled under reduced pressure to obtain 3.87 g (84%) of the resulting solid compound B'.

[0277] (3) Preparation of iridium precursor compound D'

[0278] Step 1) Preparation of compound DD

[0279]

[0280] Under a nitrogen atmosphere, a mixed solution of compound D (7.75 g, 20 mmol) and IrCl 3 (2.39 g, 8.0 mmol) dissolved in a mixed solution of ethoxyethanol: distilled water = 90 mL:30 mL was added to a 250 mL round-bottom flask. The mixed solution was heated to reflux and stirred for 24 hours. After the reaction was completed, the temperature was lowered to room temperature and the resulting solid was separated therefrom by filtration under reduced pressure. The solid was filtered through a filter and washed thoroughly with water and cold methanol, and filtered repeatedly under reduced pressure several times to obtain 6.88 g (86%) of solid compound DD.

[0281] Step 2) Preparation of iridium precursor compound D'

[0282]

[0283] In a 250 mL round-bottom flask, compound DD (8.01 g, 4 mmol) and silver trifluoromethanesulfonate (AgOTf, 3.02 g, 12 mmol) were dissolved in dichloromethane and the mixed solution was stirred at room temperature for 24 hours. After the reaction was completed, the solid precipitate was removed by filtration through diatomaceous earth. The resulting filtrate was filtered through a filter and distilled under reduced pressure to obtain 4.01 g (85%) of the resulting solid compound D'.

[0284] (4) Preparation of iridium precursor compound F'

[0285] Step 1) Preparation of compound FF

[0286]

[0287] Under a nitrogen atmosphere, a mixed solution of compound F (7.47 g, 20 mmol) and IrCl 3(2.39 g, 8.0 mmol) was dissolved in a mixed solution of ethoxyethanol: distilled water = 90 mL: 30 mL and added to a 250 mL round-bottom flask. The mixed solution was heated under reflux and stirred for 24 hours. After the reaction was completed, the temperature was lowered to room temperature, and the resulting solid was separated therefrom by filtration under reduced pressure. The solid was filtered using a filter and washed thoroughly with water and cold methanol, and filtered repeatedly under reduced pressure several times to obtain 6.54 g (84%) of the solid compound FF.

[0288] Step 2) Preparation of iridium precursor compound F’

[0289]

[0290] In a 250 mL round-bottom flask, compound FF (7.78 g, 4 mmol) and silver trifluoromethanesulfonate (AgOTf, 3.02 g, 12 mmol) were dissolved in dichloromethane and the mixed solution was stirred at room temperature for 24 hours. After the reaction was completed, the solid precipitate was removed by filtration through diatomaceous earth. The resulting filtrate was filtered through a filter and distilled under reduced pressure to obtain 4.05 g (88%) of the resulting solid compound F’.

[0291] Preparation Example - Preparation of iridium compound

[0292] 1. Preparation of iridium compound 66

[0293]

[0294] Under a nitrogen atmosphere, iridium precursor compound M’ (1.11 g, 1.5 mmol) and ligand compound A (1.07 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask, and then the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted therefrom using dichloromethane and distilled water, and the water was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain a crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate: hexane = 25:75 to obtain iridium compound 66 (1.00 g, 75%).

[0295] 2. Preparation of iridium compound 67

[0296]

[0297] Under a nitrogen atmosphere, iridium precursor compound M' (1.11 g, 1.5 mmol) and ligand compound B (1.12 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask, and then the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted therefrom using dichloromethane and distilled water, and the water was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain the crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate:hexane = 25:75 to obtain iridium compound 67 (0.96 g, 71%).

[0298] 3. Preparation of Iridium Compound 96

[0299]

[0300] Under a nitrogen atmosphere, iridium precursor compound M' (1.11 g, 1.5 mmol) and ligand compound C (1.11 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask, and then the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted therefrom using dichloromethane and distilled water, and the water was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain the crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate:hexane = 25:75 to obtain iridium compound 96 (1.03 g, 76%).

[0301] 4. Preparation of Iridium Compound 97

[0302]

[0303] Under a nitrogen atmosphere, iridium precursor compound M' (1.11 g, 1.5 mmol) and ligand compound D (1.16 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask, and then the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted therefrom using dichloromethane and distilled water, and the water was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain the crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate:hexane = 25:75 to obtain iridium compound 97 (1.11 g, 81%).

[0304] 5. Preparation of Iridium Compound 216

[0305]

[0306] Under a nitrogen atmosphere, iridium precursor compound M’ (1.11 g, 1.5 mmol) and ligand compound E (1.07 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask, and then the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted therefrom using dichloromethane and distilled water, and the water was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain a crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate:hexane = 25:75 to obtain iridium compound 216 (1.14 g, 86%).

[0307] 6. Preparation of iridium compound 217

[0308]

[0309] Under a nitrogen atmosphere, iridium precursor compound M’ (1.11 g, 1.5 mmol) and ligand compound F (1.12 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask, and then the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted therefrom using dichloromethane and distilled water, and the water was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain a crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate:hexane = 25:75 to obtain iridium compound 217 (1.09 g, 81%).

[0310] 7. Preparation of iridium compound 246

[0311]

[0312] Under a nitrogen atmosphere, iridium precursor compound M’ (1.11 g, 1.5 mmol) and ligand compound G (1.11 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask, and then the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted therefrom using dichloromethane and distilled water, and the water was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain a crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate:hexane = 25:75 to obtain iridium compound 246 (1.07 g, 79%).

[0313] 8. Preparation of Iridium Compound 247

[0314]

[0315] Under a nitrogen atmosphere, iridium precursor compound M’ (1.11 g, 1.5 mmol) and ligand compound H (1.16 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask. Then, the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted therefrom using dichloromethane and distilled water, and the moisture was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain the crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate:hexane = 25:75 to obtain iridium compound 247 (1.10 g, 80%).

[0316] 9. Preparation of Iridium Compound 309

[0317]

[0318] Under a nitrogen atmosphere, iridium precursor compound M’ (1.11 g, 1.5 mmol) and ligand compound I (1.12 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask. Then, the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted therefrom using dichloromethane and distilled water, and the moisture was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain the crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate:hexane = 25:75 to obtain iridium compound 309 (0.96 g, 71%).

[0319] 10. Preparation of Iridium Compound 319

[0320]

[0321] Under a nitrogen atmosphere, iridium precursor compound M' (1.11 g, 1.5 mmol) and ligand compound J (1.16 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask, and then the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted therefrom using dichloromethane and distilled water, and the water was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain the crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate:hexane = 25:75 to obtain iridium compound 319 (1.04 g, 76%).

[0322] 11. Preparation of iridium compound 349

[0323]

[0324] Under a nitrogen atmosphere, iridium precursor compound M' (1.11 g, 1.5 mmol) and ligand compound K (1.12 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask, and then the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted therefrom using dichloromethane and distilled water, and the water was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain the crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate:hexane = 25:75 to obtain iridium compound 349 (1.19 g, 88%).

[0325] 12. Preparation of iridium compound 359

[0326]

[0327] Under a nitrogen atmosphere, iridium precursor compound M' (1.11 g, 1.5 mmol) and ligand compound L (1.16 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask, and then the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted therefrom using dichloromethane and distilled water, and the water was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain the crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate:hexane = 25:75 to obtain iridium compound 359 (1.15 g, 84%).

[0328] 13. Preparation of iridium compound 469

[0329]

[0330] Under a nitrogen atmosphere, iridium precursor compound B’ (1.72 g, 1.5 mmol) and ligand compound N (0.47 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask, and then the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted therefrom using dichloromethane and distilled water, and the water was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain the crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate:hexane = 50:50 to obtain iridium compound 469 (1.23 g, 75%).

[0331] 14. Preparation of iridium compound 470

[0332]

[0333] Under a nitrogen atmosphere, iridium precursor compound D’ (1.76 g, 1.5 mmol) and ligand compound N (0.47 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask, and then the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted therefrom using dichloromethane and distilled water, and the water was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain the crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate:hexane = 50:50 to obtain iridium compound 470 (1.21 g, 72%).

[0334] 15. Preparation of iridium compound 479

[0335]

[0336] Under a nitrogen atmosphere, iridium precursor compound F’ (1.72 g, 1.5 mmol) and ligand compound N (0.47 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask, and then the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted therefrom using dichloromethane and distilled water, and the water was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain the crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate:hexane = 50:50 to obtain iridium compound 479 (1.28 g, 78%).

[0337] 16. Preparation of Iridium Compound 509

[0338]

[0339] Under a nitrogen atmosphere, iridium precursor compound B’ (1.72 g, 1.5 mmol) and ligand compound O (0.73 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask. Then the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature. The organic layer was extracted therefrom using dichloromethane and distilled water, and the water was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain the crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate:hexane = 40:60 to obtain iridium compound 509 (1.38 g, 80%).

[0340] 17. Preparation of Iridium Compound 510

[0341]

[0342] Under a nitrogen atmosphere, iridium precursor compound D’ (1.76 g, 1.5 mmol) and ligand compound O (0.73 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask. Then the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature. The organic layer was extracted therefrom using dichloromethane and distilled water, and the water was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain the crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate:hexane = 40:60 to obtain iridium compound 510 (1.39 g, 79%).

[0343] 18. Preparation of Iridium Compound 519

[0344]

[0345] Under a nitrogen atmosphere, an iridium precursor compound F’ (1.72 g, 1.5 mmol) and a ligand compound O (0.73 g, 3 mmol) were added to 2-ethoxyethanol (50 mL) and DMF (50 mL) in a 150 mL round-bottom flask, and then the mixed solution was heated and stirred at 130 °C for 24 hours. When the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted therefrom using dichloromethane and distilled water, and the water was removed therefrom by adding anhydrous magnesium sulfate thereto. The filtrate was obtained by filtration and concentrated under reduced pressure to obtain a crude product. The obtained crude product was purified by column chromatography under the condition of ethyl acetate:hexane = 40:60 to obtain an iridium compound 519 (1.40 g, 81%).

[0346] This example

[0347] <This Example 1>

[0348] Clean a glass substrate coated with an ITO (indium tin oxide) thin film having a thickness of , and then ultrasonically clean it with acetone. Then, dry the glass substrate. Thus, an ITO transparent electrode was formed. HI-1, which is a hole injection material, was deposited on the ITO transparent electrode by thermal vacuum deposition. Thus, a hole injection layer having a thickness of 60 nm was formed. Then, NPB, which is a hole transport material, was deposited on the hole injection layer by thermal vacuum deposition. Thus, a hole transport layer having a thickness of 80 nm was formed. Then, CBP, which is a host material of a light-emitting layer, was deposited on the hole transport layer. Compound 66 as a dopant was doped into the host material at a doping concentration of 5%. Thus, a light-emitting layer having a thickness of 30 nm was formed. ET-1:Liq (1:1) (30 nm), which is a material for an electron transport layer and an electron injection layer, was deposited on the light-emitting layer. Then, aluminum having a thickness of 100 nm was deposited thereon to form a cathode. In this way, an organic light-emitting diode emitting green light was fabricated.

[0349]

[0350]

[0351] HI-1 refers to N1,N1'-([1,1'-biphenyl]-4,4'-diyl)bis(N1,N4,N4-triphenylbenzene-1,4-diamine).

[0352] ET-1 refers to 2-(4-(9,10-di(naphthalen-2-yl)anthracen-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole.

[0353] <This Examples 2 to 18 and Comparative Examples 1 to 7>

[0354] The organic light-emitting diodes of Examples 2 to 18 and Comparative Examples 1 to 7 were fabricated in the same manner as in Example 1, except that the compounds shown in Tables 1 to 2 below were used in place of Compound 66 as the dopant in Example 1.

[0355] <Performance Evaluation of Organic Light-Emitting Diodes>

[0356] Regarding the organic light-emitting diodes prepared according to Examples 1 to 18 and Comparative Examples 1 to 7, the operating voltage and efficiency characteristics at a current of 10 mA / cm 2 were measured, as well as the lifetime characteristics during acceleration at 20 mA / cm 2 . Accordingly, the operating voltage (V), EQE (external quantum efficiency) (%), and LT95 (%) were measured and converted to values relative to those of Comparative Example 1, and the results are shown in Tables 1 to 2 below. LT95 refers to the lifetime evaluation scheme and is the time required for the organic light-emitting diode to lose 5% of its initial brightness.

[0357] Table 1

[0358]

[0359] The structures of Ref-1 to Ref-7 used as the doping materials in Comparative Examples 1 to 7 in Table 1 above are as follows.

[0360]

[0361] Table 2

[0362]

[0363] From the results in Tables 1 to 2 above, it can be determined that, compared with Comparative Examples 1 to 7, in the organic light-emitting diodes in which the organometallic compounds of each of Examples 1 to 18 according to the present disclosure are used as the dopant in the light-emitting layer of the diode, the operating voltage of the diode is reduced, and the maximum luminous efficiency, external quantum efficiency (EQE), and lifetime (LT95) of the diode are improved.

[0364] The protection scope of the present disclosure should be understood through the scope of the claims, and all technical concepts within the equivalent scope thereof should be understood to be included within the scope of the present disclosure. Although the exemplary embodiments of the present disclosure have been described in more detail with reference to the accompanying drawings, the present disclosure is not necessarily limited to these embodiments. The present disclosure can be implemented in various modified ways without departing from the technical concept of the present disclosure. Therefore, the exemplary embodiments disclosed in the present disclosure are not intended to limit the technical concept of the present disclosure, but are used to describe the present disclosure. The scope of the technical concept of the present disclosure is not limited by these exemplary embodiments. Therefore, it should be understood that the above-described exemplary embodiments are illustrative rather than restrictive in all aspects. The protection scope of the present disclosure should be interpreted by the claims, and all technical concepts within the scope of the present disclosure should be understood to be included within the scope of the present disclosure.

Claims

1. An organometallic compound represented by Chemical Formula 1: Ir(L A ) m (L B ) n (Chemical formula 1) In Chemical Formula 1, L A is represented by one selected from the group consisting of Chemical Formulas 2-1 to 2-6, L B is a bidentate ligand represented by Chemical Formula 3 m is 1 or 2, n is 1 or 2, and the sum of m and n is 3, In each of Chemical Formulas 2-1 to 2-6, X represents oxygen, R 1-1 、R 1-2 、R 1-3 、R 1-4 、R 2-1 、R 2-2 、R 3-1 、R 3-2 、R 4-1 and R 4-2 Each of which independently represents hydrogen, deuterium, an alkyl group, or a combination thereof. The bidentate ligand represented by Chemical Formula 3 includes Chemical Formula 4 or Chemical Formula 5: In Chemical Formula 4, R 5-1 、R 5-2 、R 5-3 、R 5-4 、R 6-1 、R 6-2 、R 6-3 and R 6-4 each independently represents hydrogen, deuterium, a C1-C5 straight-chain alkyl group, or a C1-C5 branched-chain alkyl group, and In Chemical Formula 5, R 7 , R 8 and R 9 Each of independently represents hydrogen, deuterium, C1-C5 straight chain alkyl, or C1-C5 branched chain alkyl, and wherein the C1-C5 linear alkyl or C1-C5 branched alkyl is substituted with deuterium.

2. The organometallic compound according to claim 1, wherein the organometallic compound represented by Chemical Formula 1 has a heteroleptic structure, where m is 1 and n is 2.

3. The organometallic compound according to claim 1, wherein the organometallic compound represented by Chemical Formula 1 has a heteroleptic structure, where m is 2 and n is 1.

4. The organometallic compound according to claim 1, wherein the organometallic compound represented by Chemical Formula 1 includes one selected from the group consisting of Compounds 1 to 6, 13 to 15, 20 to 26, 33 to 35, 40 to 46, 53 to 55, 60 to 68, 74 to 83, 90 to 98, 105 to 113, 120 to 128, 135 to 143, 150 to 156, 163 to 165, 170 to 176, 180, 183 to 185, 190 to 196, 200, 203 to 205, 210 to 218, 225 to 233, 240 to 248, 255 to 263, 270 to 278, 285 to 293, 300 to 305, 308 to 315, 318 to 325, 328 to 335, 338 to 345, 348 to 355, 358 to 365, 368 to 375, 378 to 385, 388 to 395, 398 to 405, 408 to 415, 418 to 425, 428 to 435, 438 to 445, 448 to 455, 458 to 465, 468 to 475, 478 to 485, 488 to 495, 498 to 505, 508 to 515, 518 to 525, 527 and 528:

5. An organic light-emitting diode, comprising: a first electrode; a second electrode facing the first electrode; and an organic layer disposed between the first electrode and the second electrode, wherein the organic layer includes a light-emitting layer, the light-emitting layer contains a doping material, and the doping material includes the organometallic compound according to claim 1.

6. The organic light-emitting diode according to claim 5, wherein the light-emitting layer includes a green light-emitting layer.

7. The organic light-emitting diode according to claim 5, wherein the organic layer further includes a hole injection layer, a hole transport layer, an electron transport layer, or an electron injection layer.

8. An organic light-emitting diode, comprising: a first electrode and a second electrode facing each other; and a first light-emitting stack and a second light-emitting stack located between the first electrode and the second electrode, wherein each of the first light-emitting stack and the second light-emitting stack includes at least one light-emitting layer, The at least one light-emitting layer includes a green phosphorescent light-emitting layer, the green phosphorescent light-emitting layer contains a doping material, and the doping material includes the organometallic compound according to Claim 1.

9. An organic light-emitting diode, comprising: a first electrode and a second electrode facing each other; and a first light-emitting stack, a second light-emitting stack, and a third light-emitting stack located between the first electrode and the second electrode, wherein each of the first light-emitting stack, the second light-emitting stack, and the third light-emitting stack includes at least one light-emitting layer, the at least one light-emitting layer includes a green phosphorescent light-emitting layer, the green phosphorescent light-emitting layer contains a doping material, and the doping material includes the organometallic compound according to Claim 1.

10. An organic light-emitting display device, comprising: a substrate; a driving element located on the substrate; and an organic light-emitting element, the organic light-emitting element being disposed on the substrate and connected to the driving element, wherein the organic light-emitting element includes the organic light-emitting diode according to Claim 5.

11. The organometallic compound according to Claim 1, wherein the organometallic compound represented by Chemical Formula 1 includes at least one of the following compounds:

12. An organic light-emitting diode, comprising: a first electrode; a second electrode facing the first electrode; and an organic layer disposed between the first electrode and the second electrode, wherein the organic layer includes a light-emitting layer, the light-emitting layer contains a doping material, and the doping material includes the organometallic compound according to Claim 1.

13. The organic light-emitting diode according to Claim 12, wherein the light-emitting layer includes a green light-emitting layer.

14. The organic light-emitting diode according to Claim 12, wherein the organic layer further includes a hole injection layer, a hole transport layer, an electron transport layer, or an electron injection layer.

15. An organic light-emitting diode, comprising: a first electrode; a second electrode facing the first electrode; and an organic layer disposed between the first electrode and the second electrode, wherein the organic layer includes a light-emitting layer, the light-emitting layer contains a doping material, and the doping material includes the organometallic compound according to Claim 2.

16. The organic light-emitting diode according to Claim 15, wherein the light-emitting layer includes a green light-emitting layer.

17. The organic light-emitting diode according to Claim 15, wherein the organic layer further includes a hole injection layer, a hole transport layer, an electron transport layer, or an electron injection layer.

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