Organometallic compounds and organic light-emitting diodes including such organometallic compounds

Abstract

An organometallic compound represented by the following chemical formula 1 is disclosed. This organometallic compound is used as a dopant in the light-emitting layer of an organic light-emitting diode (OLED). Therefore, the operating voltage of the diode is reduced, and the luminous efficiency and lifetime are improved: [Chemical Formula 1]Ir(L A ) m (L B ) n In chemical formula 1, L A This indicates a host ligand having an imidazole group or a benzimidazole group, and includes one selected from the group consisting of the following chemical formulas 2-1, 2-2, 2-3, 2-4, 2-5, 2-6, 2-7, and 2-8, L B The auxiliary ligand represented by the following chemical formula 3, where m and n each represent the number of ligands that bind to Ir (iridium), m is 1, 2 or 3, n is 0, 1 or 2, and the sum of m and n is 3.

Description

Technical Field

[0001] This disclosure relates to organometallic compounds, and more specifically, to organometallic compounds having phosphorescent properties and organic light-emitting diodes comprising such organometallic compounds. Background Technology

[0002] As display devices are applied in various fields, interest in them is increasing. One type of display device is the organic light-emitting display device, which includes the rapidly developing organic light-emitting diode (OLED).

[0003] In an organic light-emitting diode (OLED), when charge is injected into the light-emitting layer formed between the positive and negative electrodes, electrons and holes recombine in the light-emitting layer to form excitons, thus converting the energy of the excitons into light. This is how an OLED emits light. Compared to traditional display devices, OLEDs can operate at lower voltages, consume relatively less power, exhibit superior color, and can be used in a variety of ways due to the availability of flexible substrates. Furthermore, the size of an OLED can be freely adjusted. Summary of the Invention

[0004] Compared to liquid crystal displays (LCDs), organic light-emitting diodes (OLEDs) offer superior viewing angles and contrast ratios. Furthermore, because OLEDs do not require backlighting, they are lightweight and ultra-thin. An OLED comprises multiple organic layers between a negative electrode (electron injection electrode; cathode) and a positive electrode (hole injection electrode; anode). These multiple organic layers may include a hole injection layer, a hole transport layer, a hole transport assist layer, an electron blocking layer, and light-emitting layers, electron transport layers, etc.

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

[0006] Organic materials used in organic light-emitting diodes (OLEDs) can be mainly divided into luminescent materials and charge-transport materials. The luminescent material is a crucial factor determining the luminous efficiency of an OLED. It must possess high quantum efficiency, excellent electron and hole mobility, and exist uniformly and stably within the luminescent layer. Luminescent materials can be categorized based on the color of light emitted: blue, red, and green. Color-generating materials may include a host and dopants to improve color purity and luminous efficiency through energy transfer.

[0007] In recent years, there has been a trend towards using phosphorescent materials instead of fluorescent materials for the luminescent layer. When fluorescent materials are used, approximately 25% of the singlet states, which are excitons generated in the luminescent layer, are used for luminescence, while the majority of the 75% of the triplet states are dissipated as heat. However, when phosphorescent materials are used, both singlet and triplet states are used for luminescence.

[0008] Organometallic compounds are typically used as phosphorescent materials in organic light-emitting diodes (OLEDs). Continued research and development of phosphorescent materials is needed to address issues of low efficiency and lifespan.

[0009] Therefore, the object of the present invention is to provide an organometallic compound that can reduce operating voltage and improve efficiency and lifespan, and an organic light-emitting diode comprising an organic light-emitting layer containing the organometallic compound.

[0010] The purpose of this disclosure is not limited to the objectives described above. Other objectives and advantages not mentioned in this disclosure may be understood from the following description and will become clearer from the implementation of this disclosure. Furthermore, it will be readily understood that the objectives and advantages of this disclosure can be achieved using the means set forth in the claims and combinations thereof.

[0011] To achieve the above objectives, this disclosure provides an organometallic compound having a novel structure represented by the following chemical formula 1 and an organic light-emitting diode wherein the light-emitting layer comprises the organometallic compound as a dopant:

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

[0013] In chemical formula 1, L A This indicates a main ligand having an imidazole group or a benzimidazole group, and is selected from the group consisting of the following chemical formulas 2-1, 2-2, 2-3, 2-4, 2-5, 2-6, 2-7, and 2-8.

[0014] L B This represents the auxiliary ligand represented by the following chemical formula 3.

[0015] m and n each represent the number of ligands that bind to Ir (iridium), where m is 1, 2, or 3, and n is 0, 1, or 2, and the sum of m and n is 3.

[0016]

[0017]

[0018] In each of chemical formulas 2-1 to 2-8, X1 and X2 independently represent one of the group consisting of oxygen, sulfur, C(R)2, and NR.

[0019] R, R1, R 2-1 R 2-2 R 2'-1 R 2'-2 R 2'-3 R 2'-4 R 3-1 R 3-2 R 3'-1 R 3'-2 R 4-1 R 4-2 R 4-3 R 4'-1 R 4'-2 and R 4'-3 Each independently represents one selected from the group consisting of hydrogen, deuterium, halide, deuterated or undeuterated alkyl, cycloalkyl, heteroalkyl, aralkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, thioalkyl, sulfinyl, sulfonyl, and phosphine.

[0020] In each of chemical formulas 2-1 to 2-8, the two adjacent functional groups R 2-1 and R 2-2 They can combine to form a ring structure, R 2'-1 R 2'-2 R 2'-3 and R 2'-4 Two adjacent functional groups can combine to form a ring structure. 3-1 and R 3-2 They can combine to form a ring structure, with two adjacent functional groups R 3'-1 and R 3'-2 They can combine to form a ring structure, R 4-1 R 4-2 and R 4-3 Two adjacent functional groups can combine to form a ring structure, and R 4'-1 R 4'-2 and R 4'-3 Two adjacent functional groups can combine to form a ring structure.

[0021] The auxiliary ligand represented by chemical formula 3 is a bidentate ligand, and the auxiliary ligand is represented by one of the following chemical formulas 4 or 5:

[0022]

[0023] 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 one selected from the group consisting of hydrogen, deuterium, C1 to C5 straight-chain alkyl, and C1 to C5 branched alkyl, wherein the C1 to C5 straight-chain alkyl or C1 to C5 branched alkyl may be substituted with at least one selected from deuterium and a halogen element, R 5-1 R 5-2 R 5-3 and R 5-4 Two adjacent functional groups can combine to form a ring structure, and R 6-1 R 6-2 R 6-3 and R 6-4 Two adjacent functional groups can combine to form a ring structure.

[0024] In formula 5, R7, R8 and R9 each independently represent one selected from the group consisting of hydrogen, deuterium, C1 to C5 straight-chain alkyl, and C1 to C5 branched alkyl, wherein the C1 to C5 straight-chain alkyl or C1 to C5 branched alkyl can be substituted by at least one selected from deuterium and halogen elements, and two adjacent functional groups in R7, R8 and R9 can be combined with each other to form a cyclic structure.

[0025] The organometallic compounds according to this disclosure can be used as dopants in the light-emitting layer of organic light-emitting diodes (OLEDs), thereby reducing the operating voltage of OLEDs and improving their efficiency and lifetime characteristics.

[0026] The effects of this disclosure are not limited to those described above, and those skilled in the art will clearly understand other effects not mentioned through the following description. Attached Figure Description

[0027] Figure 1 This is a schematic cross-sectional view of an organic light-emitting diode in which the light-emitting layer comprises an organometallic compound, according to an illustrative embodiment of the present disclosure.

[0028] Figure 2 This is a schematic cross-sectional view of an organic light-emitting diode having a series structure according to an illustrative embodiment of the present disclosure, the series structure having two light-emitting stacks and comprising an organometallic compound represented by chemical formula 1.

[0029] Figure 3This is a schematic cross-sectional view of an organic light-emitting diode having a series structure according to an illustrative embodiment of the present disclosure, the series structure having two light-emitting stacks and comprising an organometallic compound represented by chemical formula 1.

[0030] Figure 4 This is a schematic cross-sectional view of an organic light-emitting display device including an organic light-emitting diode according to an illustrative embodiment of the present disclosure. Detailed Implementation

[0031] The advantages and features of this disclosure, as well as the methods for achieving these advantages and features, will become apparent from the embodiments described in detail below with reference to the accompanying drawings. However, this disclosure is not limited to the embodiments disclosed below, but can be implemented in various different forms. Therefore, these embodiments are set forth only to complete this disclosure and to fully inform those skilled in the art of the scope of this disclosure, which is limited only by the scope of the claims.

[0032] The shapes, dimensions, ratios, angles, quantities, etc., disclosed in the accompanying drawings used to describe embodiments of this disclosure are illustrative and the disclosure is not limited thereto. The same reference numerals refer to the same elements herein. Furthermore, for the sake of simplicity, descriptions and details of well-known steps and elements have been omitted. In addition, numerous specific details are set forth in the following detailed description of this disclosure to provide a thorough understanding of it. However, it should be understood that this disclosure can be practiced without these specific details. In other instances, well-known methods, processes, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of this disclosure.

[0033] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this disclosure. As used herein, the singular constructs “a” and “an” are also intended to include the plural constructs, unless the context clearly indicates otherwise. It should also be understood that, when used in this specification, the terms “comprising,” “including,” “comprises,” 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 preceding a list of elements, expressions such as “at least one” may modify the entire list of elements and may not modify individual elements of the list. In the interpretation of numerical values, errors or tolerances may be introduced, even without explicit description.

[0034] Furthermore, it should be understood that when a first element or layer is referred to as existing “on” a second element or layer, the first element may be directly disposed on the second element or may be indirectly disposed on the second element by 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 may be directly connected to or coupled to another element or layer, or one or more intermediate elements or layers may exist. Furthermore, it should be understood that when an element or layer is referred to as being “between” two elements or layers, it may be the only element or layer between the two elements or layers, or one or more intermediate elements or layers may also exist.

[0035] Furthermore, as used herein, when a layer, membrane, region, plate, etc., is disposed "on" or "on top" of another layer, membrane, region, plate, etc., the former can directly contact the latter, or another layer, membrane, region, plate, etc., can be disposed between the former and the latter. As used herein, when a layer, membrane, region, plate, etc., is directly disposed "on" or "on top" of another layer, membrane, region, plate, etc., the former directly contacts the latter, and no other layer, membrane, region, plate, etc., is disposed between the former and the latter. Furthermore, as used herein, when a layer, membrane, region, plate, etc., is disposed "below" or "under" another layer, membrane, region, plate, etc., the former can directly contact the latter, or another layer, membrane, region, plate, etc., can be disposed between the former and the latter. As used herein, when a layer, membrane, region, plate, etc., is directly disposed "below" or "under" another layer, membrane, region, plate, etc., the former directly contacts the latter, and no other layer, membrane, region, plate, etc., is disposed between the former and the latter.

[0036] In descriptions of temporal relationships, such as the temporal precedence between two events as "after," "following," or "before," unless it is specified that "immediately after," "immediately following," or "immediately before" is given, another event may occur between the two events.

[0037] It should be understood that although the terms “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. Therefore, without departing from the spirit and scope of this disclosure, the first element, component, region, layer, or part described below may be referred to as the second element, component, region, layer, or part.

[0038] The features of the various embodiments of this disclosure can be combined in whole or in part with each other, and can be technically related to or interoperable with each other. The embodiments can be implemented independently of each other, or they can be implemented together in a related relationship.

[0039] When interpreting numerical values, unless otherwise explicitly stated otherwise, the value is interpreted to include a range of error.

[0040] It should be understood that when a component or layer is referred to as being "connected to" or "coupled to" another component or layer, it can be directly located, connected to, or coupled to another component or layer, or there can be one or more intermediate components or layers. Furthermore, it should be understood that when a component or layer is referred to as being "between" two components or layers, it can be the only component or layer between the two components or layers, or there can be one or more intermediate components or layers.

[0041] Unless otherwise defined, all terms used herein, including technical and scientific terms, shall have the same meaning as commonly understood by one of ordinary skill in the art to which the inventive concept pertains. It should also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having the same meaning as their meaning in the context of the relevant field, and shall not be interpreted as having an idealized or overly formal meaning, unless expressly defined herein.

[0042] The organometallic compounds according to some embodiments of this disclosure can be represented by the following chemical formula 1. When said organometallic compound is used as a dopant in the light-emitting layer of an organic light-emitting diode, the luminous efficiency and lifetime of the diode can be improved:

[0043] [Chemical Formula 1]Ir(L A ) m (L B ) n

[0044] In chemical formula 1, L A This indicates a main ligand having an imidazole group or a benzimidazole group, and is selected from the group consisting of the following chemical formulas 2-1, 2-2, 2-3, 2-4, 2-5, 2-6, 2-7, and 2-8.

[0045] L B This represents the auxiliary ligand represented by the following chemical formula 3.

[0046] m and n each represent the number of ligands that bind to Ir (iridium), where m is 1, 2, or 3, and n is 0, 1, or 2, and the sum of m and n is 3.

[0047]

[0048]

[0049]

[0050] In each of chemical formulas 2-1 to 2-8, X1 and X2 independently represent one of the group consisting of oxygen, sulfur, C(R)2, and NR.

[0051] R, R1, R 2-1 R 2-2 R 2'-1 R 2'-2 R 2'-3 R 2'-4 R 3-1 R 3-2 R 3'-1 R 3'-2 R 4-1 R 4-2 R 4-3 R 4'-1 R 4'-2 and R 4'-3 Each independently represents one selected from the group consisting of hydrogen, deuterium, halide, deuterated or undeuterated alkyl, cycloalkyl, heteroalkyl, aralkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, thioalkyl, sulfinyl, sulfonyl, and phosphine.

[0052] In each of chemical formulas 2-1 to 2-8, the two adjacent functional groups R 2-1 and R 2-2 They can combine to form a ring structure, R 2'-1 R 2'-2 R 2'-3 and R 2'-4 Two adjacent functional groups can combine to form a ring structure. 3-1 and R 3-2 They can combine to form a ring structure, with two adjacent functional groups R 3'-1 and R 3'-2 They can combine to form a ring structure, R 4-1 R 4-2 and R 4-3 Two adjacent functional groups can combine to form a ring structure, and R 4'-1 R 4'-2 and R 4'-3 Two adjacent functional groups can combine to form a ring structure.

[0053] The auxiliary ligand represented by chemical formula 3 is a bidentate ligand, and the bidentate ligand is represented by chemical formula 4 or chemical formula 5:

[0054]

[0055] 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 one selected from the group consisting of hydrogen, deuterium, C1 to C5 straight-chain alkyl, and C1 to C5 branched alkyl, wherein the C1 to C5 straight-chain alkyl or C1 to C5 branched alkyl may be substituted with at least one selected from deuterium and a halogen element, R 5-1 R 5-2 R 5-3 and R 5-4 Two adjacent functional groups can combine to form a ring structure, and R 6-1 R 6-2 R 6-3 and R 6-4 Two adjacent functional groups can combine to form a ring structure.

[0056] In formula 5, R7, R8 and R9 each independently represent one selected from the group consisting of hydrogen, deuterium, C1 to C5 straight-chain alkyl, and C1 to C5 branched alkyl, wherein the C1 to C5 straight-chain alkyl or C1 to C5 branched alkyl can be substituted by at least one selected from deuterium and halogen elements, and two adjacent functional groups in R7, R8 and R9 can be combined with each other to form a cyclic structure.

[0057] As mentioned above, the auxiliary ligand bonded to iridium (Ir), which is the central coordinating metal, can be a bidentate ligand. Bidentate ligands can contain electron donors, thereby increasing the amount of MLCT (metal-to-ligand charge transfer), thus enabling organic light-emitting diodes to exhibit improved luminescent properties, such as high luminous efficiency and high external quantum efficiency.

[0058] The organometallic compounds according to embodiments of this disclosure may have heterogamic or homogamic structures. Specifically, the organometallic compounds according to embodiments of this disclosure may have a heterogamic structure, wherein in chemical formula 1, m is 1 and n is 2; or a heterogamic structure wherein m is 2 and n is 1; or a homogamic structure wherein m is 3 and n is 0.

[0059] Specific examples of compounds represented by Chemical Formula 1 of this disclosure may include one selected from the group consisting of compounds 1 to 510. However, specific examples of compounds represented by Chemical Formula 1 of this disclosure are not limited thereto, as long as they satisfy the limitations of Chemical Formula 1 above:

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078] According to one embodiment of this disclosure, the organometallic compound represented by chemical formula 1 of this disclosure can be used as a red phosphorescent material or a green phosphorescent material, preferably as a green phosphorescent material.

[0079] Reference Figure 1According to one embodiment of this disclosure, an organic light-emitting diode (OLED) 100 may be provided, comprising: 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 be made of an organometallic compound represented by Formula 1. Furthermore, in the OLED 100, the organic layer 130 disposed between the first electrode 110 and the second electrode 120 may 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 may be formed on the electron injection layer 180, and a protective layer (not shown) may be formed on the second electrode 120.

[0080] Furthermore, despite Figure 1 As not shown, a hole transport auxiliary layer can be further added between the hole transport layer 150 and the emitting layer 160. The hole transport auxiliary layer may contain a compound with good hole transport properties and can reduce the difference between the HOMO energy levels of the hole transport layer 150 and the emitting layer 160, thereby adjusting the hole injection characteristics. Therefore, hole accumulation at the interface between the hole transport auxiliary layer and the emitting layer 160 can be reduced, thereby reducing the quenching phenomenon caused by exciton disappearance at the interface due to polarons. Thus, device degradation can be reduced and the device can be stabilized, thereby improving its efficiency and lifetime.

[0081] The first electrode 110 can be used as a positive electrode and can be made of ITO, IZO, tin oxide, or zinc oxide, which are conductive materials with relatively large work function values. However, this disclosure is not limited thereto.

[0082] The second electrode 120 can be used as a negative electrode and may include Al, Mg, Ca, or Ag, or alloys or combinations thereof, as a conductive material having a relatively small work function value. However, this disclosure is not limited thereto.

[0083] Hole injection layer 140 may be located between first electrode 110 and hole transport layer 150. Hole injection layer 140 may have the function of improving the interface properties between first electrode 110 and hole transport layer 150, and may be selected from materials with suitable conductivity. Hole injection layer 140 may include one or more selected from the group consisting of MTDATA, CuPc, TCTA, HATCN, TDAPB, PEDOT / PSS and N1,N1'-([1,1'-biphenyl]-4,4'-diyl)bis(N1,N4,N4)-triphenylphenyl-1,4-diamine. Preferably, hole injection layer 140 may include N1,N1'-([1,1'-biphenyl]-4,4'-diyl)bis(N1,N4,N4-triphenylphenyl-1,4-diamine). However, this disclosure is not limited thereto.

[0084] The hole transport layer 150 may be located near the light-emitting layer and between the first electrode 110 and the light-emitting layer 160. The material of the hole transport layer 150 may include compounds selected from the group consisting of: TPD, NPB, CBP, N-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazole-3-yl)phenyl)-9H-fluorene-2-amine, N-(biphenyl-4-yl)-N-(4-(9-phenyl-9H-carbazole-3-yl)phenyl)biphenyl)-4-amine, etc. Preferably, the material of the hole transport layer 150 may include NPB. However, this disclosure is not limited thereto.

[0085] According to this disclosure, the light-emitting layer 160 may include a host material 160' and an organometallic compound represented by Chemical Formula 1 as a dopant 160" doped into the host to improve the luminous efficiency of the host and the organic light-emitting diode. The light-emitting layer 160 may be formed by adding about 1% to 30% by weight of the organometallic compound of Chemical Formula 1 of this disclosure, i.e., the dopant 160", to the host material 160', and may emit green or red light. More preferably, the organometallic compound of Chemical Formula 1 of this disclosure may serve as a green phosphorescent material.

[0086] In the luminescent layer 160 of this disclosure, an organometallic compound represented by chemical formula 1 can be used as a dopant 160", and a compound containing a carbazole group can be used as a host material 160'. For example, the host material containing a carbazole group can be one or more compounds selected from the structures shown in Table 1 below. However, this disclosure is not limited thereto.

[0087] Table 1

[0088]

[0089]

[0090] Furthermore, the electron transport layer 170 and the electron injection layer 180 can 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 high electron mobility so that electrons can be stably supplied to the light-emitting layer under smooth electron transport.

[0091] For example, the material of electron transport layer 170 may include compounds selected from the group consisting of: Alq3 (tris(8-hydroxyquinoline)aluminum), Liq (lithium 8-hydroxyquinoline), PBD (2-(4-biphenyl))-5-(4-tert-butylphenyl)-1,3,4-oxadiazole), TAZ (3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole), spiro-PBD, BAlq (bis(2-methyl-8-quinoline acid)-4-(phenylphenol)aluminum), SAlq, TPBi (2,2',2-(1,3,5-benztriyl)-tris(1-phenyl-1-H-benzimidazole), oxadiazole, triazole, phenanthrene, benzoxazole, benzothiazole, and 2-(4-(9,10-bis(naphthyl-2-yl)anthracene-2-yl)phenyl)-1-phenyl-1H-benzimidazole. Preferably, the material of the electron transport layer 170 may include 2-(4-(9,10-bis(naphthyl-2-yl)anthracene-2-yl)phenyl)-1-phenyl-1H-benzimidazole. However, this disclosure is not limited thereto.

[0092] The electron injection layer 180 is used to facilitate electron injection, and the material of the electron injection layer may include compounds selected from the group consisting of Alq3 (tris(8-hydroxyquinoline)aluminum), PBD, TAZ, spiro-PBD, BAlq, SAlq, etc. However, this disclosure is not limited thereto. Alternatively, the electron injection layer 180 may be made of a metal compound. The metal compound may include one or more selected from the group consisting of Liq, LiF, NaF, KF, RbF, CsF, FrF, BeF2, MgF2, CaF2, SrF2, BaF2, and RaF2. However, this disclosure is not limited thereto.

[0093] The organic light-emitting diode (OLED) according to this disclosure can be implemented as a white OLED with a series structure. A series OLED according to an illustrative embodiment of this disclosure can be formed as a structure in which adjacent light-emitting stacks of two or more light-emitting stacks are connected to each other via a charge-generating layer (CGL). The OLED may include at least two light-emitting stacks disposed on a substrate, each of the at least two light-emitting stacks including 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 of a specific wavelength band. In this case, the light-emitting layer in at least one of the multiple light-emitting stacks may contain an organometallic compound represented by Chemical Formula 1 according to this disclosure as a dopant. Adjacent light-emitting stacks in the series structure may be connected to each other via a charge-generating layer CGL including an N-type charge-generating layer and a P-type charge-generating layer.

[0094] Figure 2 and Figure 3 This is a schematic cross-sectional view of an organic light-emitting diode in a series structure having two light-emitting stacks and an organic light-emitting diode in a series structure having three light-emitting stacks, according to some embodiments of the present disclosure.

[0095] like Figure 2 As shown, the organic light-emitting diode 100 according to this 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-generating layer CGL located between the first light-emitting stack ST1 and the second light-emitting stack ST2. The charge-generating layer CGL may include an N-type charge-generating layer 291 and a P-type charge-generating layer 292. At least one of the first light-emitting layer 261 and the second light-emitting layer 262 may contain an organometallic compound represented by chemical formula 1 according to this disclosure as a dopant. For example, such as... Figure 2 As 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.

[0096] like Figure 3As shown, the organic light-emitting diode 100 according to this disclosure includes a first electrode 110 and a second electrode 120 facing each other, and an organic layer 330 located between the first electrode 110 and the second electrode 120. The organic layer 330 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 including a second light-emitting layer 262, a third light-emitting stack ST3 including a third light-emitting layer 263, a first charge-generating layer CGL1 located between the first light-emitting stack ST1 and the second light-emitting stack ST2, and a second charge-generating layer CGL2 located between the second light-emitting stack ST2 and the third light-emitting stack ST3. The first charge-generating layer CGL1 may include an N-type charge-generating layer 291 and a P-type charge-generating layer 292. The second charge-generating layer CGL2 may include an N-type charge-generating layer 293 and a P-type charge-generating 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 contain an organometallic compound represented by Chemical Formula 1 as a dopant according to the present disclosure. For example, such as Figure 3 As 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.

[0097] Furthermore, an organic light-emitting diode according to an embodiment of the present disclosure may include a series structure, wherein four or more light-emitting stacks and three or more charge-generating layers are disposed between a first electrode and a second electrode.

[0098] The organic light-emitting diodes according to this disclosure can be used as light-emitting elements in both organic light-emitting display devices and lighting devices. In one embodiment, Figure 4 This is a schematic cross-sectional view of an organic light-emitting display device that includes an organic light-emitting diode as its light-emitting element according to some embodiments of the present disclosure.

[0099] like Figure 4 As shown, the organic light-emitting display device 3000 includes a substrate 3010, an organic light-emitting diode 4000, and an encapsulation film 3900 covering the organic light-emitting diode 4000. A driving thin-film transistor Td, which serves 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.

[0100] Despite Figure 4It is not explicitly shown that, on substrate 3010, gate lines and data lines that intersect each other to define pixel regions, a power line that extends parallel to and is spaced apart from one of the gate lines and data lines, a switching thin-film transistor connected to the gate lines and data lines, and a storage capacitor connected to an electrode of the thin-film transistor and the power line are further formed.

[0101] 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.

[0102] Semiconductor layer 3100 can be formed on substrate 3010 and can be made of oxide semiconductor material or polysilicon. When semiconductor layer 3100 is made of oxide semiconductor material, a light-shielding pattern (not shown) can be formed below semiconductor layer 3100. The light-shielding pattern prevents light from incident into semiconductor layer 3100, thereby preventing semiconductor layer 3010 from deteriorating due to light. Alternatively, semiconductor layer 3100 can be made of polysilicon. In this case, both edges of semiconductor layer 3100 can be doped with impurities.

[0103] A gate insulating layer 3200 made of 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.

[0104] 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 a switching thin-film transistor.

[0105] An interlayer insulating layer 3400 made of 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 inorganic insulating materials such as silicon oxide or silicon nitride, or organic insulating materials such as benzocyclobutene or optical acrylic.

[0106] The interlayer insulating layer 3400 has a first semiconductor layer contact hole 3420 and a second semiconductor layer contact hole 3440 defined therein to expose opposite sides of the semiconductor layer 3100, respectively. The first semiconductor layer contact hole 3420 and the second semiconductor layer contact hole 3440 are located on opposite sides of the gate 3300 and spaced apart from the gate 3300.

[0107] Source 3520 and drain 3540, made of a conductive material such as metal, are formed on the interlayer insulating layer 3400. Source 3520 and drain 3540 are located around the gate 3300 and spaced apart from each other, and each contacts opposite sides of the semiconductor layer 3100 through a first semiconductor layer contact hole 3420 and a second semiconductor layer contact hole 3440, respectively. Source 3520 is connected to a power supply line (not shown).

[0108] Semiconductor layer 3100, gate 3300, source 3520 and drain 3540 constitute driving thin film transistor Td. Driving thin film transistor Td has a coplanar structure, wherein gate 3300, source 3520 and drain 3540 are located on top of semiconductor layer 3100.

[0109] Alternatively, the driving thin-film transistor Td can have an anti-interleaved structure, where 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 can be made of amorphous silicon. In one example, the switching thin-film transistor (not shown) can have substantially the same structure as the driving thin-film transistor (Td).

[0110] In one example, the organic light-emitting display device 3000 may include a color filter 3600 that absorbs light generated from an 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 can be formed separately in different pixel areas. Each of these color filter patterns may be configured 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. Using the color filter 3600 enables the organic light-emitting display device 3000 to achieve full color.

[0111] For example, when the organic light-emitting display device 3000 is a bottom-emitting type, the light-absorbing color filter 3600 can be disposed on a portion 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-emitting type, the color filter can be disposed on the top of the organic light-emitting diode 4000, i.e., on the top of the second electrode 4200. For example, the color filter 3600 can be formed to have a thickness of 2-5 μm.

[0112] In one example, a protective layer 3700 is formed to cover the driving thin-film transistor Td, the protective layer 3700 having a drain contact hole 3720 defined therein for exposing the drain 3540 of the driving thin-film transistor Td.

[0113] On the protective layer 3700, each first electrode 4100 connected to the drain 3540 of the driving thin film transistor Td via a drain contact hole 3720 is formed in each pixel region.

[0114] The first electrode 4100 can be used as a positive electrode (anode) and can be made of a conductive material with 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.

[0115] In one example, when the organic light-emitting display device 3000 is a top-emitting type, a reflective electrode or reflective layer may be further formed below the first electrode 4100. For example, the reflective electrode or reflective layer may be made of one of aluminum (Al), silver (Ag), nickel (Ni), and aluminum-palladium-copper (APC) alloys.

[0116] A dam layer 3800 covering the edge of the first electrode 4100 is formed on the protective layer 3700. The dam layer 3800 exposes the center of the first electrode 4100 corresponding to the pixel region.

[0117] An organic layer 4300 is formed on the first electrode 4100. The organic light-emitting diode 4000 may have a series structure if needed. For information on series structures, please refer to... Figures 2 to 4 This illustrates some embodiments of the present disclosure and the above description thereof.

[0118] The 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 area and is made of a conductive material with 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 aluminum (Al), magnesium (Mg), and an aluminum-magnesium alloy (Al-Mg).

[0119] The first electrode 4100, the organic layer 4300, and the second electrode 4200 constitute an organic light-emitting diode 4000.

[0120] An encapsulation film 3900 is formed on the second electrode 4200 to prevent external moisture from penetrating into the organic light-emitting diode 4000. Although in Figure 4 It is not explicitly shown that the encapsulation film 3900 may have a three-layer structure in which a first inorganic layer, an organic layer, and an inorganic layer are stacked sequentially. However, this disclosure is not limited thereto.

[0121] In the following description, examples of the synthesis of this disclosure and this embodiment will be described. However, the following embodiment is merely an example of this disclosure. This disclosure is not limited thereto.

[0122] Synthetic Example - Preparation of Ligand Intermediates

[0123] <Preparation of ligand A-2>

[0124]

[0125] In a 1 L round-bottom flask under a nitrogen atmosphere, SM-1 (24.70 g, 0.10 mol), SM-3 (13.61 g, 0.20 mol), (1R,2R)-cyclohexane-1,2-diamine (22.83 g, 0.20 mol), copper iodide (I) (1.90 g, 0.01 mol), and cesium carbonate (97.75 g, 0.30 mol) were dissolved in 500 mL of DMF. The mixture was then heated and stirred overnight. When the reaction was complete, the reaction vessel was cooled to room temperature, and the mixture was filtered through a diatomaceous earth filter. The organic layer was extracted with ethyl acetate and distilled water and separated. The water in the organic layer was removed using anhydrous magnesium sulfate, and the organic layer was filtered through a filter and then concentrated under reduced pressure. The crude product was recrystallized from ethyl acetate and hexane to obtain A-2 (17.87 g, 76%).

[0126] <Preparation of ligand B-2>

[0127]

[0128] In a 1 L round-bottom flask under a nitrogen atmosphere, SM-1 (24.70 g, 0.10 mol), SM-4 (47.22 g, 0.20 mol), (1R,2R)-cyclohexane-1,2-diamine (22.83 g, 0.20 mol), copper iodide (I) (1.90 g, 0.01 mol), and cesium carbonate (97.75 g, 0.30 mol) were dissolved in 500 mL of DMF. The mixture was then heated and stirred overnight. When the reaction was complete, the reaction vessel was cooled to room temperature, and the mixture was filtered through a diatomaceous earth filter. The organic layer was extracted with ethyl acetate and distilled water. The water in the organic layer was removed using anhydrous magnesium sulfate, and the organic layer was filtered through a filter and then concentrated under reduced pressure. The crude product was recrystallized from ethyl acetate and hexane to obtain B-2 (17.40 g, 61%).

[0129] <Preparation of ligand G-2>

[0130]

[0131] In a 1 L round-bottom flask under a nitrogen atmosphere, SM-2 (24.60 g, 0.10 mol), SM-3 (13.61 g, 0.20 mol), (1R,2R)-cyclohexane-1,2-diamine (22.83 g, 0.20 mol), copper iodide (I) (1.90 g, 0.01 mol), and cesium carbonate (97.75 g, 0.30 mol) were dissolved in 500 mL of DMF. The mixture was then heated and stirred overnight. When the reaction was complete, the reaction vessel was cooled to room temperature, and the mixture was filtered through a diatomaceous earth filter. The organic layer was extracted with ethyl acetate and distilled water and separated. The water in the organic layer was removed using anhydrous magnesium sulfate, and the organic layer was filtered through a filter and then concentrated under reduced pressure. The crude product was recrystallized from ethyl acetate and hexane to obtain G-2 (19.19 g, 82%).

[0132] <Preparation of ligand H-2>

[0133]

[0134] In a 1 L round-bottom flask under a nitrogen atmosphere, SM-2 (24.60 g, 0.10 mol), SM-4 (47.22 g, 0.20 mol), (1R,2R)-cyclohexane-1,2-diamine (22.83 g, 0.20 mol), copper iodide (I) (1.90 g, 0.01 mol), and cesium carbonate (97.75 g, 0.30 mol) were dissolved in 500 mL of DMF. The mixture was then heated and stirred overnight. When the reaction was complete, the reaction vessel was cooled to room temperature, and the mixture was filtered through a diatomaceous earth filter. The organic layer was extracted with ethyl acetate and distilled water and separated. The water in the organic layer was removed using anhydrous magnesium sulfate, and the organic layer was filtered through a filter and then concentrated under reduced pressure. The crude product was recrystallized from ethyl acetate and hexane to obtain H-2 (20.74 g, 73%).

[0135] <Preparation of ligand A-1>

[0136]

[0137] In a 500 mL round-bottom flask under a nitrogen atmosphere, A-2 (11.75 g, 0.05 mol) was dissolved in 250 mL of ethyl acetate. Then, methyl iodoform (42.58 g, 0.30 mol) was added sequentially to the reaction solution, and the reaction solution was stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was filtered and concentrated under reduced pressure to obtain compound A-1 (17.90 g, 85%).

[0138] <Preparation of Ligand B-1>

[0139]

[0140] In a 500 mL round-bottom flask under a nitrogen atmosphere, B-2 (14.25 g, 0.05 mol) was dissolved in 250 mL of ethyl acetate. Then, methyl iodoform (42.58 g, 0.30 mol) was added sequentially to the reaction solution, and the reaction solution was stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was filtered and concentrated under reduced pressure to obtain compound B-1 (19.55 g, 83%).

[0141] <Preparation of ligand C-1>

[0142]

[0143] In a 500 mL round-bottom flask under a nitrogen atmosphere, A-2 (11.75 g, 0.05 mol) was dissolved in 250 mL of ethyl acetate. Then, 2-iodopropane (42.58 g, 0.30 mol) was added sequentially to the reaction solution, and the reaction solution was stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was filtered and concentrated under reduced pressure to obtain compound C-1 (17.51 ​​g, 78%).

[0144] <Preparation of Ligand D-1>

[0145]

[0146] In a 500 mL round-bottom flask under a nitrogen atmosphere, B-2 (14.25 g, 0.05 mol) was dissolved in 250 mL of ethyl acetate. Then, 2-iodopropane (51.00 g, 0.30 mol) was added sequentially to the reaction solution, and the reaction solution was stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was filtered and concentrated under reduced pressure to obtain compound D-1 (20.46 g, 82%).

[0147] <Preparation of ligand E-1>

[0148]

[0149] In a 500 mL round-bottom flask under a nitrogen atmosphere, A-2 (11.75 g, 0.05 mol) was dissolved in 250 mL of ethyl acetate. Then, 1-iodobutane (51.00 g, 0.30 mol) was added sequentially to the reaction solution, and the reaction solution was stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was filtered and concentrated under reduced pressure to obtain compound E-1 (18.52 g, 80%).

[0150] <Preparation of ligand F-1>

[0151]

[0152] In a 500 mL round-bottom flask under a nitrogen atmosphere, B-2 (14.25 g, 0.05 mol) was dissolved in 250 mL of ethyl acetate. Then, 1-iodobutane (51.00 g, 0.30 mol) was added sequentially to the reaction solution, and the reaction solution was stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was filtered and concentrated under reduced pressure to obtain compound F-1 (21.55 g, 84%).

[0153] <Preparation of ligand G-1>

[0154]

[0155] In a 500 mL round-bottom flask under a nitrogen atmosphere, G-2 (11.70 g, 0.05 mol) was dissolved in 250 mL of ethyl acetate. Then, iodomethane (55.21 g, 0.30 mol) was added sequentially to the reaction solution, and the reaction solution was stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was filtered and concentrated under reduced pressure to obtain compound G-1 (18.70 g, 89%).

[0156] <Preparation of ligand H-1>

[0157]

[0158] In a 500 mL round-bottom flask under a nitrogen atmosphere, H-2 (14.20 g, 0.05 mol) was dissolved in 250 mL of ethyl acetate. Then, iodomethane (55.21 g, 0.30 mol) was added sequentially to the reaction solution, and the reaction solution was stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was filtered and concentrated under reduced pressure to obtain compound H-1 (19.04 g, 81%).

[0159] <Preparation of Ligand I-1>

[0160]

[0161] In a 500 mL round-bottom flask under a nitrogen atmosphere, G-2 (11.70 g, 0.05 mol) was dissolved in 250 mL of ethyl acetate. Then, 2-iodopropane (55.21 g, 0.30 mol) was added sequentially to the reaction solution, and the reaction solution was stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was filtered and concentrated under reduced pressure to obtain compound I-1 (19.72 g, 88%).

[0162] <Preparation of Ligand J-1>

[0163]

[0164] In a 500 mL round-bottom flask under a nitrogen atmosphere, H₂ (14.20 g, 0.05 mol) was dissolved in 250 mL of ethyl acetate. Then, 2-iodopropane (42.58 g, 0.30 mol) was added sequentially to the reaction solution, and the reaction solution was stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was filtered and concentrated under reduced pressure to obtain compound J₁ (22.42 g, 90%).

[0165] <Preparation of ligand K-1>

[0166]

[0167] In a 500 mL round-bottom flask under a nitrogen atmosphere, G-2 (11.70 g, 0.05 mol) was dissolved in 250 mL of ethyl acetate. Then, 1-iodobutane (42.58 g, 0.30 mol) was added sequentially to the reaction solution, and the reaction solution was stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was filtered and concentrated under reduced pressure to obtain compound K-1 (19.64 g, 85%).

[0168] <Preparation of ligand L-1>

[0169]

[0170] In a 500 mL round-bottom flask under a nitrogen atmosphere, H₂ (14.20 g, 0.05 mol) was dissolved in 250 mL of ethyl acetate. Then, 1-iodobutane (42.58 g, 0.30 mol) was added sequentially to the reaction solution, and the reaction solution was stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was filtered and concentrated under reduced pressure to obtain compound L₁ (22.79 g, 89%).

[0171] Synthetic Example - Preparation of Ligands

[0172] <Preparation of Ligand A>

[0173]

[0174] In a 500 mL round-bottom flask under a nitrogen atmosphere, reactant A-1 (21.05 g, 0.05 mol) and silver oxide (5.80 g, 0.025 mol) were dissolved in 250 mL acetonitrile. The reaction solution was then stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was concentrated under reduced pressure to obtain compound A (22.94 g, 95%), which was used for the next reaction without further purification.

[0175] <Preparation of Ligand B>

[0176]

[0177] In a 500 mL round-bottom flask under a nitrogen atmosphere, reactant B-1 (23.55 g, 0.05 mol) and silver oxide (5.80 g, 0.025 mol) were dissolved in 250 mL acetonitrile. The reaction solution was then stirred at room temperature for 24 hours. After the reaction was complete, the reaction solution was concentrated under reduced pressure to obtain compound B (24.51 g, 92%), which was used for the next reaction without further purification.

[0178] <Preparation of Ligand C>

[0179]

[0180] In a 500 mL round-bottom flask under a nitrogen atmosphere, reactant C-1 (22.46 g, 0.05 mol) and silver oxide (5.80 g, 0.025 mol) were dissolved in 250 mL acetonitrile. The reaction solution was then stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was concentrated under reduced pressure to obtain compound C (22.74 g, 89%), which was used for the next reaction without further purification.

[0181] <Preparation of Ligand D>

[0182]

[0183] In a 500 mL round-bottom flask under a nitrogen atmosphere, reactant D-1 (24.96 g, 0.05 mol) and silver oxide (5.80 g, 0.025 mol) were dissolved in 250 mL acetonitrile. The reaction solution was then stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was concentrated under reduced pressure to obtain compound D (23.56 g, 84%), which was used for the next reaction without further purification.

[0184] <Preparation of Ligand E>

[0185]

[0186] In a 500 mL round-bottom flask under a nitrogen atmosphere, reactant E-1 (23.16 g, 0.05 mol) and silver oxide (5.80 g, 0.025 mol) were dissolved in 250 mL acetonitrile. The reaction solution was then stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was concentrated under reduced pressure to obtain compound E (23.86 g, 91%), which was used for the next reaction without further purification.

[0187] <Preparation of ligand F>

[0188]

[0189] In a 500 mL round-bottom flask under a nitrogen atmosphere, reactant F-1 (25.66 g, 0.05 mol) and silver oxide (5.80 g, 0.025 mol) were dissolved in 250 mL acetonitrile. The reaction solution was then stirred at room temperature for 24 hours. After the reaction was complete, the reaction solution was concentrated under reduced pressure to obtain compound F (26.45 g, 92%), which was used for the next reaction without further purification.

[0190] <Preparation of Ligand G>

[0191]

[0192] In a 500 mL round-bottom flask under a nitrogen atmosphere, reactant G-1 (21.00 g, 0.05 mol) and silver oxide (5.80 g, 0.025 mol) were dissolved in 250 mL acetonitrile. The reaction solution was then stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was concentrated under reduced pressure to obtain compound G (20.24 g, 84%), which was used for the next reaction without further purification.

[0193] <Preparation of ligand H>

[0194]

[0195] In a 500 mL round-bottom flask under a nitrogen atmosphere, reactant H-1 (23.50 g, 0.05 mol) and silver oxide (5.80 g, 0.025 mol) were dissolved in 250 mL acetonitrile. The reaction solution was then stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was concentrated under reduced pressure to obtain compound H (23.14 g, 89%), which was used for the next reaction without further purification.

[0196] <Preparation of Ligand I>

[0197]

[0198] In a 500 mL round-bottom flask under a nitrogen atmosphere, reactant I-1 (22.41 g, 0.05 mol) and silver oxide (5.80 g, 0.025 mol) were dissolved in 250 mL acetonitrile. The reaction solution was then stirred at room temperature for 24 hours. After the reaction was complete, the reaction solution was concentrated under reduced pressure to obtain compound I (22.95 g, 90%), which was used for the next reaction without further purification.

[0199] <Preparation of Ligand J>

[0200]

[0201] In a 500 mL round-bottom flask under a nitrogen atmosphere, reactant J-1 (24.91 g, 0.05 mol) and silver oxide (5.80 g, 0.025 mol) were dissolved in 250 mL acetonitrile. The reaction solution was then stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was concentrated under reduced pressure to obtain compound J (25.48 g, 91%), which was used for the next reaction without further purification.

[0202] <Preparation of ligand K>

[0203]

[0204] In a 500 mL round-bottom flask under a nitrogen atmosphere, reactant K-1 (23.11 g, 0.05 mol) and silver oxide (5.80 g, 0.025 mol) were dissolved in 250 mL acetonitrile. The reaction solution was then stirred at room temperature for 24 hours. After the reaction was complete, the reaction solution was concentrated under reduced pressure to obtain compound K (24.89 g, 95%), which was used for the next reaction without further purification.

[0205] <Preparation of ligand L>

[0206]

[0207] In a 500 mL round-bottom flask under a nitrogen atmosphere, reactant L-1 (25.61 g, 0.05 mol) and silver oxide (5.80 g, 0.025 mol) were dissolved in 250 mL acetonitrile. The reaction solution was then stirred at room temperature for 24 hours. When the reaction was complete, the reaction solution was concentrated under reduced pressure to obtain compound L (26.98 g, 94%), which was used for the next reaction without further purification.

[0208] Synthetic Example - Preparation of Iridium Compounds

[0209] <Preparation of Iridium Compound 1>

[0210]

[0211] In a 150 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M1 (1.61 g, 1.5 mmol) and ligand A (1.45 g, 3 mmol) were dissolved in o-xylene (150 mL), and the reaction solution was stirred under reflux for 18 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at ethyl acetate:hexane = 25:75 to obtain the aforementioned iridium compound 1 (1.68 g, 75%).

[0212] <Preparation of Iridium Compound 2>

[0213]

[0214] In a 150 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M1 (1.61 g, 1.5 mmol) and ligand B (1.60 g, 3 mmol) were dissolved in o-xylene (150 mL), and the reaction solution was stirred under reflux for 18 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at ethyl acetate:hexane = 25:75 to obtain the aforementioned iridium compound 2 (1.63 g, 68%).

[0215] <Preparation of Iridium Compound 16>

[0216]

[0217] In a 150 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M1 (1.61 g, 1.5 mmol) and ligand G (1.46 g, 3 mmol) were dissolved in o-xylene (150 mL), and the reaction solution was stirred under reflux for 18 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at ethyl acetate:hexane = 25:75 to obtain the aforementioned iridium compound 16 (1.57 g, 70%).

[0218] <Preparation of Iridium Compound 17>

[0219]

[0220] In a 150 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M1 (1.61 g, 1.5 mmol) and ligand H (1.60 g, 3 mmol) were dissolved in o-xylene (150 mL), and the reaction solution was stirred under reflux for 18 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at ethyl acetate:hexane = 25:75 to obtain the aforementioned iridium compound 17 (1.94 g, 81%).

[0221] <Preparation of Iridium Compound 91>

[0222]

[0223] In a 150 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M1 (1.61 g, 1.5 mmol) and ligand C (1.53 g, 3 mmol) were dissolved in o-xylene (150 mL), and the reaction solution was stirred under reflux for 18 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at ethyl acetate:hexane = 25:75 to obtain the aforementioned iridium compound 91 (1.89 g, 81%).

[0224] <Preparation of Iridium Compound 92>

[0225]

[0226] In a 150 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M1 (1.61 g, 1.5 mmol) and ligand D (1.68 g, 3 mmol) were dissolved in o-xylene (150 mL), and the reaction solution was stirred under reflux for 18 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at ethyl acetate:hexane = 25:75 to obtain the aforementioned iridium compound 92 (1.87 g, 76%).

[0227] <Preparation of Iridium Compound 106>

[0228]

[0229] In a 150 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M1 (1.61 g, 1.5 mmol) and ligand I (1.53 g, 3 mmol) were dissolved in o-xylene (150 mL), and the reaction solution was stirred under reflux for 18 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at ethyl acetate:hexane = 25:75 to obtain the aforementioned iridium compound 106 (1.75 g, 75%).

[0230] <Preparation of Iridium Compound 107>

[0231]

[0232] In a 150 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M1 (1.61 g, 1.5 mmol) and ligand J (1.68 g, 3 mmol) were dissolved in o-xylene (150 mL), and the reaction solution was stirred under reflux for 18 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at ethyl acetate:hexane = 25:75 to obtain the aforementioned iridium compound 107 (1.69 g, 68%).

[0233] <Preparation of Iridium Compound 181>

[0234]

[0235] In a 150 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M1 (1.61 g, 1.5 mmol) and ligand E (1.57 g, 3 mmol) were dissolved in o-xylene (150 mL), and the reaction solution was stirred under reflux for 18 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at ethyl acetate:hexane = 25:75 to obtain the aforementioned iridium compound 181 (1.90 g, 80%).

[0236] <Preparation of Iridium Compound 182>

[0237]

[0238] In a 150 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M1 (1.61 g, 1.5 mmol) and ligand F (1.72 g, 3 mmol) were dissolved in o-xylene (150 mL), and the reaction solution was stirred under reflux for 18 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at ethyl acetate:hexane = 25:75 to obtain the aforementioned iridium compound 182 (1.64 g, 65%).

[0239] <Preparation of Iridium Compound 196>

[0240]

[0241] In a 150 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M1 (1.61 g, 1.5 mmol) and ligand K (1.57 g, 3 mmol) were dissolved in o-xylene (150 mL), and the reaction solution was stirred under reflux for 18 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at ethyl acetate:hexane = 25:75 to obtain the aforementioned iridium compound 196 (1.87 g, 79%).

[0242] <Preparation of Iridium Compound 197>

[0243]

[0244] In a 150 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M1 (1.61 g, 1.5 mmol) and ligand L (1.72 g, 3 mmol) were dissolved in o-xylene (150 mL), and the reaction solution was stirred under reflux for 18 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at ethyl acetate:hexane = 25:75 to obtain the aforementioned iridium compound 197 (1.87 g, 74%).

[0245] <Preparation of Iridium Compound 466>

[0246]

[0247] In a 250 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M2 (2.17 g, 1.5 mmol) and ligand L1 (0.47 g, 3 mmol) were dissolved in toluene (100 mL), and the reaction solution was stirred under reflux for 24 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at a toluene:hexane ratio of 1:1 to obtain the aforementioned iridium compound 466 (1.82 g, 72%).

[0248] <Preparation of Iridium Compound 468>

[0249]

[0250] In a 150 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M2 (2.17 g, 1.5 mmol) and ligand L2 (0.30 g, 3 mmol) were dissolved in a mixed solvent (2-ethoxyethanol:DMF = 40 mL:40 mL), and the reaction solution was refluxed and stirred at 135 °C for 24 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at a toluene:hexane ratio of 1:3 to obtain the aforementioned iridium compound 468 (1.39 g, 59%).

[0251] <Preparation of Iridium Compound 470>

[0252]

[0253] In a 250 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M3 (2.33 g, 1.5 mmol) and ligand L1 (0.47 g, 3 mmol) were dissolved in toluene (100 mL), and the reaction solution was stirred under reflux for 24 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at a toluene:hexane ratio of 1:1 to obtain the aforementioned iridium compound 470 (1.42 g, 53%).

[0254] <Preparation of Iridium Compound 472>

[0255]

[0256] In a 150 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M3 (2.33 g, 1.5 mmol) and ligand L2 (0.30 g, 3 mmol) were dissolved in a mixed solvent (2-ethoxyethanol:DMF = 40 mL:40 mL), and the reaction solution was refluxed and stirred at 135 °C for 24 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at a toluene:hexane ratio of 1:3 to obtain the aforementioned iridium compound 472 (1.82 g, 72%).

[0257] <Preparation of Iridium Compound 474>

[0258]

[0259] In a 250 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M4 (2.42 g, 1.5 mmol) and ligand L1 (0.47 g, 3 mmol) were dissolved in toluene (100 mL), and the reaction solution was stirred under reflux for 24 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at a toluene:hexane ratio of 1:1 to obtain the aforementioned iridium compound 474 (1.75 g, 63%).

[0260] <Preparation of Iridium Compound 476>

[0261]

[0262] In a 150 mL round-bottom flask under a nitrogen atmosphere, iridium precursor M4 (2.42 g, 1.5 mmol) and ligand L2 (0.30 g, 3 mmol) were dissolved in a mixed solvent (2-ethoxyethanol:DMF = 40 mL:40 mL), and the reaction solution was refluxed and stirred at 135 °C for 24 hours. When the reaction was complete, the temperature was lowered to room temperature. The organic layer was then extracted with dichloromethane and distilled water, and water was removed by adding anhydrous magnesium sulfate. The filtrate was filtered and subjected to reduced pressure to obtain the crude product. The crude product was purified by column chromatography at a toluene:hexane ratio of 1:3 to obtain the aforementioned iridium compound 476 (1.77 g, 68%).

[0263] This embodiment

[0264] <Example 1>

[0265] It is coated with a layer of ITO (indium tin oxide) with a thickness of [missing information]. The glass substrate of the thin film was washed, and the glass substrate was ultrasonically cleaned and dried using acetone. A 60 nm thick HI-1 (N1,N1'-([1,1'-biphenyl]-4,4'-diyl)bis(N1,N4,N4-triphenylphenyl-1,4-diamine)) structure was formed as a hole injection material on the prepared ITO transparent electrode by thermal vacuum deposition. An 80 nm thick NPB hole transport material was thermally vacuum deposited on the hole injection layer. A light-emitting layer was thermally vacuum deposited on the hole transport material. In this respect, the light-emitting layer contained CBP as the host material and compound 1 as a dopant. The doping concentration was 5%, and the thickness of the light-emitting layer was 30 nm. An ET-1:Liq(1:1) (30 nm) material, serving as both the electron transport layer and the electron injection layer, was thermally vacuum deposited on the light-emitting layer. Then, a 100 nm thick aluminum layer was deposited on top to form the negative electrode. Thus, an organic light-emitting diode was manufactured. The materials used in Example 1 described above are as follows.

[0266]

[0267] HI-1 refers to N1,N1'-([1,1'-biphenyl]-4,4'-diyl)bis(N1,N4,N4-triphenylphenyl-1,4-diamine).

[0268] ET-1 refers to 2-(4-(9,10-bis(naphthyl-2-yl)anthracene-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole.

[0269] <Examples 2 to 12 and Comparative Examples 1 to 5>

[0270] Organic light-emitting diodes of each of Examples 2 to 12 and Comparative Examples 1 to 5 were manufactured in the same manner as in Example 1, except that the compounds shown in Table 2 below were used instead of compound 1 as dopants in Example 1.

[0271] Table 2

[0272]

[0273] The structures of the dopant materials Ref-1 to Ref-5, which are comparative examples 1 to 5, in Table 2 are as follows.

[0274]

[0275] <Examples 13 to 18 and Comparative Examples 6 to 10>

[0276] Organic light-emitting diodes of each of Examples 13 to 18 and Comparative Examples 6 to 10 were manufactured in the same manner as in Example 1, except that the compounds shown in Table 3 below were used instead of compound 1 as dopants in Example 1.

[0277] Table 3

[0278]

[0279]

[0280] The structures of the dopant materials Ref-6 to Ref-10, which are comparative examples 6 to 10, are shown in Table 3 below.

[0281]

[0282] <Examples 19 to 23>

[0283] The organic light-emitting diodes of each of Examples 19 to 23 are manufactured in the same manner as in Example 1, except that the compounds shown in Table 4 below are used instead of CBP as the main body in Example 1.

[0284] Table 4

[0285]

[0286] The structures of GH1 to GH5, the main materials of Examples 19 to 23 in Table 4, are as follows, and their compound names are described in Table 1 above.

[0287]

[0288] <Examples 24 to 28>

[0289] The organic light-emitting diodes of each of Examples 24 to 28 are manufactured in the same manner as in Example 2, except that the compounds shown in Table 5 below are used instead of CBP as the main body in Example 2. The structures of the main body materials GH1 to GH5 are the same as those described with reference to Examples 19 to 23.

[0290] Table 5

[0291]

[0292] The results in Tables 2 and 3 above show that, compared with the organic light-emitting diodes of Comparative Examples 1 to 10, the operating voltage of the organic light-emitting diodes of Examples 1 to 18, which use organometallic compounds of Chemical Formula 1 according to the present disclosure as dopants for the light-emitting layer of the diode, is reduced, and the maximum luminous quantum efficiency, external quantum efficiency (EQE), and lifetime (LT95) of the diode are improved.

[0293] The scope of protection of this disclosure should be understood through the scope of the claims, and all technical concepts within the scope of the claims should be understood to be included within the scope of this disclosure. Although embodiments of this disclosure have been described in more detail with reference to the accompanying drawings, this disclosure is not necessarily limited to these embodiments. This disclosure can be implemented in various modifications without departing from the scope of the technical concept of this disclosure. Therefore, the embodiments disclosed in this disclosure are not intended to limit the technical concept of this disclosure, but are used to describe this disclosure. The scope of the technical concept of this disclosure is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are illustrative and not restrictive in all respects. The scope of protection of this disclosure should be interpreted through the claims, and all technical concepts within the scope of this disclosure should be understood to be included within the scope of this disclosure.

Claims

1. An organic light-emitting diode, comprising: First electrode; The second electrode facing the first electrode; and An organic layer disposed between the first electrode and the second electrode. The organic layer mentioned above includes a light-emitting layer. The light-emitting layer comprises an organometallic compound containing the following compounds, and The organometallic compound is used as a dopant in the light-emitting layer:

2. The organic light-emitting diode according to claim 1, wherein the organometallic compound is used as a green phosphorescent material.

3. The organic light-emitting diode according to claim 1, wherein the host material of the light-emitting layer comprises a compound containing a carbazole group.

4. The organic light-emitting diode according to claim 3, wherein the carbazole-containing compound comprises at least one compound selected from the following structures:

5. The organic light-emitting diode according to claim 1, wherein the organic layer further comprises at least one selected from the group consisting of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer.

6. An organic light-emitting display device, comprising: substrate; Drive elements located on the substrate; and An organic light-emitting element, wherein the organic light-emitting element is disposed on the substrate and connected to the driving element, wherein the organic light-emitting element comprises an organic light-emitting diode according to any one of claims 1 to 5.

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