Organic electroluminescence device and polycyclic compound for organic electroluminescence device

Abstract

An organic electroluminescence device of the embodiment includes a first electrode, a second electrode, and an emission layer disposed between the first electrode and the second electrode and including a polycyclic compound, wherein the polycyclic compound includes a boron amine derivative, a first ring and a second ring each directly connected to a boron atom of the boron amine derivative, a third ring and a fourth ring each directly connected to a nitrogen atom of the boron amine derivative, and at least one substituted or unsubstituted boron-based group connected to at least one of the first ring to the fourth ring, thereby showing a long lifetime characteristic and excellent color reproducibility.

Description

[0001] Cross Reference to Related Applications

[0002] This patent application claims priority to Korean Patent Application No. 10-2019-0125555, filed on October 10, 2019, the contents of which are incorporated herein in its entirety. TECHNICAL FIELD

[0003] The present disclosure relates herein to an organic electroluminescent device and a polycyclic compound for use in the organic electroluminescent device, and more particularly, to a polycyclic compound for use as a light-emitting material and an organic electroluminescent device comprising the same. BACKGROUND

[0004] Recently, interest in development of an organic electroluminescent display device as an image display has been increasing. Unlike a liquid crystal display device, an organic electroluminescent display device is a so-called self-luminescent display device in which holes and electrons injected from a first electrode and a second electrode recombine in an emission layer, and a light-emitting material including an organic compound in the emission layer emits light to generate a display.

[0005] In the application of an organic electroluminescent device to a display device, reduction of a driving voltage of the organic electroluminescent device, and increase of emission efficiency and lifespan are desired. Accordingly, a material having improved properties such as a driving voltage and emission efficiency is required for an organic electroluminescent device.

[0006] In particular, recently, in order to realize an organic electroluminescent device having high efficiency, a technology such as phosphorescent emission using energy in a triplet state or delayed fluorescent emission using a phenomenon of generation of a singlet exciton through collision of triplet excitons (triplet-triplet annihilation, TTA) has been developed, and a material undergoing thermally activated delayed fluorescence (TADF) using a delayed fluorescence phenomenon has been developed. SUMMARY

[0007] The present disclosure provides an organic electroluminescent device showing good lifespan characteristics and excellent emission efficiency.

[0008] The present disclosure also provides a polycyclic compound, which is a material for an organic electroluminescent device having high color purity and long lifespan characteristics.

[0009] Embodiments of the inventive concept provide a polycyclic compound represented by the following Formula 1:

[0010] Formula 1

[0011]

[0012] In Formula 1, Ar1to Ar4are each independently a substituted or unsubstituted aryl group with 6 to 30 carbon atoms used for forming a ring, or a substituted or unsubstituted heteroaryl group with 2 to 30 carbon atoms used for forming a ring, a to d are each independently an integer of 0 to 4, where at least one of a to d is an integer of 1 or more than 1. m1to m4are each independently 0 or 1, L1to L4are each independently a direct bond, *-O-*, *-S-*, *-C(=O)-*, *-SO2-*, or *-NRa-*. R1to R4and Raare each independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a nitro group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group with 2 to 20 carbon atoms, a substituted or unsubstituted aryl group with 6 to 30 carbon atoms used for forming a ring, or a substituted or unsubstituted heteroaryl group with 2 to 30 carbon atoms used for forming a ring, R1to R4and Raare each independently optionally linked to an adjacent group to form a ring, and when at least one of a to d is an integer of 1 or more than 1, then at least one of R1to R4is a substituted or unsubstituted boron group.

[0013] In an embodiment, Formula 1 can be represented by any one of Formula 1A to Formula 1C:

[0014] Formula 1A

[0015]

[0016] Formula 1B

[0017]

[0018] Formula 1C

[0019]

[0020] In Formula 1A to Formula 1C, Ar1to Ar4, a to d, L1to L4, and R1to R4are the same as defined in Formula 1.

[0021] In an embodiment, Formula 1 can be represented by Formula 1D:

[0022] Formula 1D

[0023]

[0024] In Formula 1D, a to d, m1to m4, L1to L4, and R1to R4are the same as defined in Formula 1.

[0025] In an embodiment, Formula 1 can be represented by any one of Formula 1-1 to Formula 1-4:

[0026] Formula 1-1

[0027]

[0028] Formula 1-2

[0029]

[0030] Formula 1-3

[0031]

[0032] Formula 1-4

[0033]

[0034] In Formula 1-1, y1 is an integer of 0 to 3. In Formula 1-1 to Formula 1-4, R 11 to R 17 , R 21 to R 25 , R 31 to R 36 , and R 41 to R 45 each independently are a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, R 11 to R 17 , R 21 to R 25 , R 31 to R 36 , and R 41 to R 45 each independently are optionally linked to an adjacent group to form a ring. x1 to x17 each independently are an integer of 0 to 4, z1 to z5 each independently are an integer of 0 to 5. W1 to W5 each independently are a direct bond, *-O-* or *-NRa-*, and Ra is the same as defined in Formula 1.

[0035] In an embodiment, at least one of R1 to R4 can be a deuterium atom, an alkyl group having 1 to 20 carbon atoms substituted with a deuterium atom, an alkenyl group having 2 to 20 carbon atoms substituted with a deuterium atom, an aryl group having 6 to 30 carbon atoms for forming a ring substituted with a deuterium atom, or a heteroaryl group having 2 to 30 carbon atoms for forming a ring substituted with a deuterium atom.

[0036] In an embodiment, the polycyclic compound represented by Formula 1 can be a blue dopant emitting blue light having a central wavelength of about 470 nm or less than 470 nm.

[0037] In an embodiment, the polycyclic compound represented by Formula 1 can be a material for emitting thermally activated delayed fluorescence.

[0038] In an embodiment of the inventive concept, there is provided an organic electroluminescent device comprising: a first electrode; a second electrode disposed on the first electrode; and an emission layer disposed between the first electrode and the second electrode and comprising a polycyclic compound, wherein the polycyclic compound comprises: a boron amine derivative; a first ring and a second ring each directly connected to a boron atom of the boron amine derivative; a third ring and a fourth ring each directly connected to a nitrogen atom of the boron amine derivative; and at least one substituted or unsubstituted boronyl group connected to at least one ring among the first ring to the fourth ring. Also, the first electrode and the second electrode each independently comprise: one selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn; a compound selected from two or more among them; a mixture selected from two or more among them; and an oxide selected from one or more among them.

[0039] In an embodiment, the boron atom of the substituted or unsubstituted boronyl group can not be directly connected to an adjacent nitrogen atom.

[0040] In an embodiment, at least two adjacent rings selected from the first ring to the fourth ring can be directly connected, connected to each other via a linker, or connected with an adjacent substituent to form a fused ring.

[0041] In an embodiment, the fused ring can comprise an azaborinine moiety.

[0042] In an embodiment, the first ring to the fourth ring can each independently be a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring.

[0043] In an embodiment, the first ring to the fourth ring can each independently be a substituted or unsubstituted benzene ring.

[0044] In an embodiment, at least one hydrogen atom in the polycyclic compound can be substituted with a deuterium atom.

[0045] In an embodiment, the polycyclic compound included in the emission layer can be the polycyclic compound represented by Formula 1 above.

[0046] In an embodiment, the emission layer can emit delayed fluorescence.

[0047] In an embodiment, the emission layer can include a host and a dopant, and the dopant can include the polycyclic compound.

[0048] In an embodiment, the emission layer can emit light having a center wavelength of about 430 nm to about 470 nm. BRIEF DESCRIPTION OF DRAWINGS

[0049] The accompanying drawings, which are included to provide a further understanding of the present inventive concept and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the present inventive concept and together with the description serve to explain the principles of the present inventive concept. In the drawings:

[0050] Figure 1 FIG. 1 is schematically illustrates a cross-sectional view of an organic electroluminescent device according to an exemplary embodiment;

[0051] Figure 2 FIG. 2 is schematically illustrates a cross-sectional view of an organic electroluminescent device according to an exemplary embodiment;

[0052] Figure 3 FIG. 3 is schematically illustrates a cross-sectional view of an organic electroluminescent device according to an exemplary embodiment; and

[0053] Figure 4 FIG. 4 is schematically illustrates a cross-sectional view of an organic electroluminescent device according to an exemplary embodiment. DETAILED DESCRIPTION

[0054] The present inventive concept can have various modifications and can be implemented in different forms and will be explained in detail with reference to the accompanying drawings. However, the present inventive concept can be implemented in different forms and should not be construed as being limited to the embodiments set forth herein. Rather, all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present inventive concept should be included in the present inventive concept.

[0055] It will be understood that when an element (or components, regions, layers or the like) is referred to as being "on" another element, connected to another element, or linked to another element, it can be directly on, connected, or linked to the other element or intervening elements can be present. As used herein, the terms "a," "an," "the," and "at least one" are used interchangeably and mean one or more than one.

[0056] The same reference numerals are used throughout the drawings to refer to the same or like elements. Also, in the drawings, the thickness, ratio, and size of constituent elements can be exaggerated for effective explanation of the technology.

[0057] The term "and / or" includes a combination of one or more of the associated elements.

[0058] It will be understood that, although the terms first, second, etc. can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, a first element could be termed a second element without departing from the teachings of the present application. Similarly, a second element could be termed a first element without departing from the teachings of the present application. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0059] In addition, the terms "below," "under," "above," and "on" are used to explain the relationship of elements shown in the drawings. The terms are relative concepts and are explained based on the direction shown in the drawings.

[0060] Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. It should be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0061] It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

[0062] Hereinafter, an organic electroluminescent device according to an embodiment of the present inventive concept will be explained with reference to the accompanying drawings.

[0063] Figures 1 to 4 is a cross-sectional view schematically illustrating an organic electroluminescent device according to an exemplary embodiment of the present inventive concept. Reference is made to Figures 1 to 4 In the organic electroluminescent device 10 according to the embodiment, the first electrode EL1 and the second electrode EL2 are disposed opposite to each other, and between the first electrode EL1 and the second electrode EL2, an emission layer EML can be disposed.

[0064] Further, the organic electroluminescent device 10 of the embodiment further includes a plurality of functional groups between the first electrode EL1 and the second electrode EL2, in addition to the emission layer EML. The plurality of functional groups can include a hole transport region HTR and an electron transport region ETR. That is, the organic electroluminescent device 10 of the embodiment can include the first electrode EL1, the hole transport region HTR, the emission layer EML, the electron transport region ETR, and the second electrode EL2, which are sequentially laminated. Further, the organic electroluminescent device 10 of the embodiment can include a capping layer CPL disposed on the second electrode EL2.

[0065] The organic electroluminescent device 10 of the embodiment can include the polycyclic compound of the embodiment to be explained later in the emission layer EML disposed between the first electrode EL1 and the second electrode EL2. However, the embodiment of the present inventive concept is not limited thereto, and the organic electroluminescent device 10 of the embodiment can include the polycyclic compound of the embodiment to be explained later in the hole transport region HTR or the electron transport region ETR, which is a plurality of functional groups disposed between the first electrode EL1 and the second electrode EL2, other than the emission layer EML.

[0066] Meanwhile, when compared with Figure 1 , Figure 2 a cross-sectional view of the organic electroluminescent device 10 of the embodiment is illustrated, in which the hole transport region HTR includes a hole injection layer HIL and a hole transport layer HTL, and the electron transport region ETR includes an electron injection layer EIL and an electron transport layer ETL. Further, when compared with Figure 1 , Figure 3 a cross-sectional view of the organic electroluminescent device 10 of the embodiment is illustrated, in which the hole transport region HTR includes a hole injection layer HIL, a hole transport layer HTL, and an electron blocking layer EBL, and the electron transport region ETR includes an electron injection layer EIL, an electron transport layer ETL, and a hole blocking layer HBL. When compared with Figure 2 , Figure 4 a cross-sectional view of the organic electroluminescent device 10 of the embodiment is illustrated, which includes a capping layer CPL disposed on the second electrode EL2.

[0067] The first electrode EL1 has conductivity. The first electrode EL1 can be formed using a metal alloy or a conductive compound. The first electrode EL1 can be an anode. The first electrode EL1 can be a pixel electrode. The first electrode EL1 can be a transmissive electrode, a semi-transmissive and reflective electrode, or a reflective electrode. If the first electrode EL1 is a transmissive electrode, the first electrode EL1 can be formed using a transparent metal oxide, such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), and indium tin zinc oxide (ITZO). If the first electrode EL1 is a semi-transmissive and reflective electrode or a reflective electrode, the first electrode EL1 can include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, a compound thereof, or a mixture thereof (e.g., a mixture of Ag and Mg). In addition, the first electrode EL1 can have a structure including a plurality of layers including a reflective layer or a semi-transmissive and reflective layer formed using the above materials, and a transmissive conductive layer formed using ITO, IZO, ZnO, or ITZO. For example, the first electrode EL1 can include a three-layer structure of ITO / Ag / ITO. However, embodiments of the inventive concept are not limited thereto. The thickness of the first electrode EL1 can be about 10 nm to about 1,000 nm, about 100 nm to about 1,000 nm, or about 200 nm to about 800 nm. to about For example, about to about

[0068] A hole transport region HTR is provided on the first electrode EL1. The hole transport region HTR can include at least one of a hole injection layer HIL, a hole transport layer HTL, a hole buffer layer (not shown), and an electron blocking layer EBL. The thickness of the hole transport region HTR can be about 10 nm to about 1,000 nm, about 100 nm to about 1,000 nm, or about 200 nm to about 800 nm. to about

[0069] The hole transport region HTR can have a single layer formed using a single material, a single layer formed using a plurality of different materials, or a multi-layer structure including a plurality of layers formed using a plurality of different materials.

[0070] For example, the hole transport region HTR can have a structure of a single layer of a hole injection layer HIL or a hole transport layer HTL, or can have a structure of a single layer formed using a hole injection material and a hole transport material. Alternatively, the hole transport region HTR can have a structure of a single layer formed using a plurality of different materials, or a structure of a hole injection layer HIL / hole transport layer HTL, a hole injection layer HIL / hole transport layer HTL / hole buffer layer (not shown), a hole injection layer HIL / hole buffer layer (not shown), a hole transport layer HTL / hole buffer layer, or a hole injection layer HIL / hole transport layer HTL / electron blocking layer EBL laminated from the first electrode EL1, but is not limited thereto.

[0071] The hole transport region HTR can be formed using various methods, such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) method, inkjet printing, laser printing, and laser induced thermal imaging (LITI) method.

[0072] The hole injection layer HIL can include, for example, a phthalocyanine compound (e.g., copper phthalocyanine), N,N'-diphenyl-N,N'-bis-[4-(phenyl-m-tolyl- amino)-phenyl]-phenyl-4,4'-diamine (DNTPD), 4,4',4"-[tris(3-methylphenyl)phenylamino] triphenylamine (m-MTDATA), 4,4',4"-tris(N,N-diphenylamino)triphenylamine (TDATA), 4,4',4"-tris{N-(2-naphthyl)-N-phenylamino}-triphenylamine (2-TNATA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), polyaniline / camphor sulfonic acid (PANI / CSA), polyaniline / poly(4-styrenesulfonate) (PANI / PSS), N,N'-bis(1-naphthyl)-N,N'-diphenyl-benzidine (NPB), triphenylamine-containing polyether ketone (TPAPEK), 4-isopropyl-4'-methyl diphenyl iodonium [tetra(pentafluorophenyl)borate], and dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN).

[0073] The hole transport layer HTL can include, for example, a carbazole derivative (e.g., N-phenylcarbazole and polyvinylcarbazole), a fluorene-based derivative, N,N'-bis(3- methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD), a triphenylamine-based derivative (e.g., 4,4',4"-tris(carbazol-9-yl)triphenylamine (TCTA)), N,N'-bis(1- naphthyl)-N,N'-diphenyl-benzidine (NPB), 4,4'-cyclohexylidenebis[N,N-bis(4- methylphenyl)benzenamine] (TAPC), 4,4'-bis[N,N'-(3-methylphenyl)amino]-3,3'- dimethylbiphenyl (HMTPD), 1,3-bis(N-carbazolyl)benzene (mCP), and the like.

[0074] The thickness of the hole transport region HTR can be, for example, about 1 nm to about 1000 nm. The thickness of the hole transport region HTR can be, for example, about 1 nm to about 1000 nm. The thickness of the hole transport region HTR can be, for example, about 1 nm to about 1000 nm. The thickness of the hole transport region HTR can be, for example, about 1 nm to about 1000 nm. The thickness of the hole injection layer HIL can be, for example, about 1 nm to about 1000 nm. The thickness of the hole injection layer HIL can be, for example, about 1 nm to about 1000 nm. And the thickness of the hole transport layer HTL can be about to about For example, the thickness of the electron blocking layer EBL can be about to about If the thicknesses of the hole transport region HTR, the hole injection layer HIL, the hole transport layer HTL, and the electron blocking layer EBL satisfy the ranges described above, satisfactory hole transport properties can be achieved without a significant increase in driving voltage.

[0075] In addition to the materials described above, the hole transport region HTR can further include a charge generating material to increase conductivity. The charge generating material can be uniformly or non-uniformly dispersed in the hole transport region HTR. The charge generating material can be, for example, a p-dopant. The p-dopant can be one of a quinone derivative, a metal oxide, and a compound including a cyano group, but is not limited thereto. For example, non-limiting examples of the p-dopant can include a quinone derivative (e.g., tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanoquinodimethane (F4-TCNQ)), a metal oxide (e.g., tungsten oxide and molybdenum oxide), but are not limited thereto.

[0076] As described above, in addition to the hole injection layer HIL and the hole transport layer HTL, the hole transport region HTR can further include at least one of a hole buffer layer (not shown) and an electron blocking layer EBL. The hole buffer layer (not shown) can compensate for an optical resonance distance according to a wavelength of light emitted from the emission layer EML and can increase light emission efficiency. The materials that can be included in the hole transport region HTR can be used as the materials included in the hole buffer layer (not shown). The electron blocking layer EBL is a layer that functions to prevent electron injection from the electron transport region ETR to the hole transport region HTR.

[0077] The emission layer EML is provided on the hole transport region HTR. The emission layer EML can have a thickness of, for example, about to about or about to about The emission layer EML can have a single layer formed using a single material, a single layer formed using a plurality of different materials, or a multi-layer structure having a plurality of layers formed using a plurality of different materials.

[0078] In the organic electroluminescent device 10 of the embodiments, the emission layer EML can include the polycyclic compound of the embodiments.

[0079] The polycyclic compound according to the embodiments can include a boron amine derivative. The boron amine derivative includes a direct bond portion between a boron atom (B) and a nitrogen atom (N), and can include portion.

[0080] The polycyclic compound according to the embodiments can include a boron amine derivative, a first ring and a second ring each connected to a B atom of the boron amine derivative, and a third ring and a fourth ring each connected to an N atom of the boron amine derivative. In addition, the polycyclic compound of the embodiments can include at least one substituted or unsubstituted boron group, which is substituted in at least one of the first ring to the fourth ring.

[0081] In addition, in the polycyclic compound of the embodiments, the B atom of the substituted or unsubstituted boron group is not directly connected to the N atom of the boron amine derivative, and the B atom of the substituted or unsubstituted boron group can not be directly connected to the N atom of the adjacent substituent.

[0082] Meanwhile, in the description, the substituent of the substituted group corresponds to at least one of a deuterium atom, a halogen atom, a cyano group, a nitro group, an amino group, a silyl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, a sulfinyl group, a sulfonyl group, a carbonyl group, a boron group, a phosphine oxide group, a phosphine sulfide group, an alkyl group, an alkenyl group, an alkynyl group, a hydrocarbon ring group, an aryl group, a heterocyclic group, and any combination thereof. In addition, each of the exemplified substituents can be substituted or unsubstituted. For example, a biphenyl group can be interpreted as an aryl group or a phenyl group substituted with a phenyl group.

[0083] In the description, the term "connected to an adjacent group to form a ring" means forming a substituted or unsubstituted hydrocarbon ring, or a substituted or unsubstituted heterocyclic ring, via bonding with an adjacent group. The hydrocarbon ring includes an aliphatic hydrocarbon ring and an aromatic hydrocarbon ring. The heterocyclic ring includes an aliphatic heterocyclic ring and an aromatic heterocyclic ring. The ring formed by bonding with the adjacent group can be a single ring or a polycyclic ring. In addition, the ring formed by bonding of the adjacent group can be combined with another ring to form a spiro structure.

[0084] In the description, the term "adjacent group" means a pair of substituent groups in which a first substituent is connected to an atom directly connected to another atom substituted with a second substituent, a pair of substituent groups connected to the same atom and different from each other, or a substituent spatially positioned at the closest position to the corresponding substituent. For example, in 1,2-dimethylbenzene, the two methyl groups can be interpreted as "adjacent groups" to each other, and in 1,1-diethylcyclopentane, the two ethyl groups can be interpreted as "adjacent groups" to each other.

[0085] In the description, examples of the halogen atom can include a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

[0086] In the description, an alkyl group can be a linear, branched, or cyclic type. The number of carbons of the alkyl group can be 1 to 50, 1 to 30, 1 to 20, 1 to 10, or 1 to 6. Examples of the alkyl group can include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, isobutyl, 2-ethylbutyl, 3,3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, t-pentyl, cyclopentyl, 1-methylpentyl, 3-methylpentyl, 2-ethylpentyl, 4-methyl-2-pentyl, n-hexyl, 1-methylhexyl, 2-ethylhexyl, 2-butylhexyl, cyclohexyl, 4-methylcyclohexyl, 4-t-butylcyclohexyl, n-heptyl, 1-methylheptyl, 2,2-dimethylheptyl, 2-ethylheptyl, 2-butylheptyl, n-octyl, t-octyl, 2-ethyloctyl, 2-butyloctyl, 2-hexyloctyl, 3,7-dimethyloctyl, cyclooctyl, n-nonyl, n-decyl, adamantyl, 2-ethyldodecyl, 2-butyldodecyl, 2-hexyldodecyl, 2-octyldodecyl, n-undecyl, n-dodecyl, 2-ethyldodecyl, 2-butyldodecyl, 2-hexyldodecyl, 2-octyldodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, 2-ethylhexadecyl, 2-butyihexadecyl, 2-hexylhexadecyl, 2-octylhexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, 2-ethyleicosyl, 2-butyileicosyl, 2-hexyleicosyl, 2-octyleicosyl, n- heneicosyl, n-docosyl, n-tricosyl, n-tetracosyl, n-pentacosyl, n-hexacosyl, n-heptacosyl, n-octacosyl, n-nonacosyl, n-triacontyl, and the like, but are not limited thereto.

[0087] In the description, a hydrocarbon ring group means a functional group or a substituent derived from an aliphatic hydrocarbon ring. The hydrocarbon ring group can be a saturated hydrocarbon ring group having 5 to 20 carbon atoms for forming a ring.

[0088] In the description, an aryl group means a functional group or a substituent derived from an aromatic hydrocarbon ring. The aryl group can be a monocyclic aryl group or a polycyclic aryl group. The number of carbons for forming a ring in the aryl group can be 6 to 30, 6 to 20, or 6 to 15. Examples of the aryl group can include phenyl, naphthyl, fluorenyl, anthryl, phenanthryl, biphenyl, terphenyl, quaterphenyl, quinquephenyl, sexiphenyl, benzophenanthryl, pyrenyl, benzofluoranthene, chrysenyl, triphenylenyl, pyranthryl, picenyl, hexaphenylbenzenyl, coronenyl, ovalenyl, hexaphenylhexaenyl, and the like, but are not limited thereto.

[0089] ​In the description, a heterocyclic group can contain one or more than one of B, O, N, P, Si, Se, Ge, and S as a heteroatom. If the heterocyclic group contains two or more heteroatoms, the two or more heteroatoms can be the same or different. The heterocyclic group can be a monocyclic heterocyclic group or a polycyclic heterocyclic group, and has the concept including a heteroaryl group. The number of carbons for forming a ring of the heterocyclic group can be 2 to 30, 2 to 20, or 2 to 10.

[0090] In the description, a heteroaryl group can contain one or more than one of B, O, N, P, Si, Se, Ge, and S as a heteroatom. If the heteroaryl group contains two or more heteroatoms, the two or more heteroatoms can be the same or different. The heteroaryl group can be a monocyclic heteroaryl group or a polycyclic heteroaryl group. The number of carbons for forming a ring of the heteroaryl group can be 2 to 30, 2 to 20, or 2 to 10. Examples of the heteroaryl group can include thienyl, furanyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, oxadiazolyl, triazolyl, pyridyl, bipyridyl, pyrimidyl, triazinyl, acridinyl, pyridazinyl, pyrazinyl, quinolinyl, quinazolinyl, quinoxalinyl, phenoxazinyl, phthalazinyl, pyridopyrimidyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolinyl, indolyl, carbazolyl, N-arylcarbazolyl, N-heteroarylcarbazolyl, N-alkylcarbazolyl, benzoxazolyl, benzimidazolyl, benzothiazolyl, benzocarbazolyl, benzothiophenyl, dibenzothiophenyl, thienothiophenyl, benzofuranyl, phenanthrolinyl, isoxazolyl, thiadiazolyl, phenothiazinyl, dibenzothiopholyl, dibenzofuranyl, and the like, but are not limited thereto.

[0091] In the description, an alkoxy group can be a straight chain, a branched chain, or a cyclic chain. The number of carbons of the alkoxy group is not particularly limited, but can be, for example, 1 to 20 or 1 to 10. Examples of the alkoxy group can include methoxy, ethoxy, n-propoxy, i-propoxy, butoxy, pentoxy, hexyloxy, octyloxy, nonyloxy, decyloxy, and the like. However, embodiments of the present inventive concept are not limited thereto.

[0092] In the description, the number of carbons for forming a ring of an aryloxy group is not particularly limited, but can be, for example, 6 to 30, 6 to 20, or 6 to 15.

[0093] In the description, an alkylthio group can be a straight chain, a branched chain, or a cyclic chain. The number of carbons of the alkylthio group is not particularly limited, but can be, for example, 1 to 20 or 1 to 10. Examples of the alkylthio group can include -S-methyl, -S-ethyl, -S-n-propyl, -S-i-propyl, and the like. However, embodiments of the present inventive concept are not limited thereto.

[0094] In the description, the number of carbons of the arylthio group for forming a ring is not particularly limited, but can be, for example, 6 to 30, 6 to 20, or 6 to 15.

[0095] In the description, the boron group includes alkylboron groups and arylboron groups. Examples of the boron group include trimethylboron group, triethylboron group, tert-butyldimethylboron group, triphenylboron group, diphenylboron group, phenylboron group, and the like, but are not limited thereto. For example, the alkyl group in the alkylboron group can be the same as the above exemplified alkyl group, and the aryl group in the arylboron group can be the same as the above exemplified aryl group.

[0096] In the description, the alkenyl group can be linear or branched. The number of carbons of the alkenyl group is not particularly limited, but can be 2 to 30, 2 to 20, or 2 to 10. Examples of the alkenyl group include ethenyl group, 1-butenyl group, 1-pentenyl group, 1,3-butyldienyl group, styryl group, styrylvinyl group, and the like, but are not limited thereto.

[0097] In the description, the number of carbons of the amine group is not particularly limited, but can be 1 to 30. The amine group can include alkylamine groups and arylamine groups. Examples of the amine group include methylamine group, dimethylamine group, phenylamine group, diphenylamine group, naphthylamine group, 9-methyl-anthrylamine group, and the like, but are not limited thereto. For example, the alkyl group in the alkylamine group can be the same as the above exemplified alkyl group, and the aryl group in the arylamine group can be the same as the above exemplified aryl group.

[0098] In the description, the direct bond can mean a single bond.

[0099] Meanwhile, in the description, “-*” means a connection position.

[0100] In the polycyclic compound according to the embodiment, the first to fourth rings bound to the boron amine derivative can each independently be a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring. For example, in the polycyclic compound according to the embodiment, the first to fourth rings can each independently be a substituted or unsubstituted benzene ring.

[0101] In the polycyclic compound of the embodiment, at least two of the first to fourth rings adjacent to each other can be connected to each other to form a ring. For example, two or more adjacent first to fourth rings can be directly connected, connected to each other via a linker, or connected to each other with a substituent adjacent thereto to form a fused ring. In the polycyclic compound of the embodiment, the fused ring formed by the binding of the adjacent rings can include a nitrogen borazine moiety.

[0102] Further, at least one substituted or unsubstituted boron-based group included in the polycyclic compound of the embodiments can be combined with an adjacent linker or an adjacent substituent to form a fused ring. For example, the fused ring formed by the combination of the substituted or unsubstituted boron-based group with the adjacent group can include an azaborinane ring.

[0103] That is, in the polycyclic compound of the embodiments, at least one substituted or unsubstituted boron-based group can be combined with at least one of the adjacent first to fourth rings, the adjacent linker, and the adjacent substituent to form a fused ring.

[0104] The emission layer EML of the organic electroluminescent device 10 of the embodiments can include the polycyclic compound of the embodiments represented by the following Formula 1:

[0105] Formula 1

[0106]

[0107] In Formula 1, Ar1 to Ar4 can each independently be a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring. For example, Ar1 to Ar4 can each independently be a substituted or unsubstituted phenyl ring. Meanwhile, among Ar1 to Ar4, Ar1 and Ar2 can correspond to the first and second rings directly connected to the boron atom of the boron amine derivative, and Ar3 and Ar4 can correspond to the third and fourth rings directly connected to the nitrogen atom of the boron amine derivative.

[0108] In Formula 1, a to d are each independently an integer of 0 to 4. Further, in Formula 1, at least one of a to d is an integer of 1 or greater than 1. Meanwhile, in the case where a to d are each independently an integer of 2 or greater than 2, the plurality of R1 groups to R4 groups can be the same or at least one of which can be different. For example, in the case where a is an integer of 2 or greater than 2, the plurality of R1 groups can be the same or at least one of which can be different from the rest. The above explanation is an example, and the same explanation can be applied to the R2 group to the R4 group for the case where each of b to d is an integer of 2 or greater than 2.

[0109] In the polycyclic compound represented by Formula 1, R1 to R4 can each independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a nitro group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, or R1 to R4 can each independently optionally be linked with an adjacent group to form a ring. In addition, at least one of R1 to R4 is a substituted or unsubstituted boron-based group.

[0110] That is, in the case where at least one of a to d is an integer of 1 or more than 1, at least one of R1 groups to R4 groups can be a substituted or unsubstituted boron-based group. Thus, the polycyclic compound of the embodiments can further include at least one boron atom as a ring-forming atom in addition to the boron atom in B-N having a direct bond between the boron atom and the nitrogen atom. The additional boron atom other than the boron atom in the B-N bond can not be directly bound to the nitrogen atom.

[0111] In Formula 1, m1 to m4 are each independently 0 or 1. In the case where m1 to m4 are 0, this means that the adjacent rings are not connected to each other. In the polycyclic compound of the embodiments, at least one of m1 to m4 can be 1. For example, m2 and m4 can be 1, and m1 and m3 can be 0. In addition, m1 can be 0, and m2 to m4 can be 1. However, the embodiments of the present inventive concept are not limited thereto, and at least one selected from m1 to m4 can be 1.

[0112] In Formula 1, L1 to L4 can each independently be a direct bond, *-O-*, *-S-*, *-C(=O)-*, *-SO2-*, or *-NRa-*. Meanwhile, Ra can be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a nitro group, a substituted or unsubstituted amine group, a substituted or unsubstituted oxy group, a substituted or unsubstituted thio group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, L1 to L4 can each independently optionally be linked with an adjacent group to form a ring.

[0113] For example, in a case where any one of L1 to L4 is a direct bond, two adjacent rings can be connected via a single bond. In a case where any one of L1 to L4 is NRa, two adjacent rings can be connected to each other via a nitrogen atom (N) of NRa.

[0114] Two adjacent rings connected to each other via any one of the linkers (i.e., L1 to L4) can form a fused ring including at least one of a boron atom and a nitrogen atom of boron amine as a ring-forming atom. For example, a fused ring formed by connecting two adjacent rings via a linker can include an azaborinane moiety.

[0115] Further, substituents of Ar1 to Ar4, and adjacent linkers among L1 to L4 that are linkers connecting two adjacent rings, can be connected to each other to form a fused ring. For example, a substituent of one of Ar1 to Ar4 and a linker adjacent to a selected ring can be connected to each other to form a fused ring including an azaborinane moiety.

[0116] In the polycyclic compound of the embodiment, a fused ring formed by connecting a substituent of one of Ar1 to Ar4 and a linker adjacent to a selected ring and substituent can include a moiety represented by any one of the following FR-1 to FR-3:

[0117]

[0118] Meanwhile, in the polycyclic compound of the embodiment represented by Formula 1, at least one of R1 to R4 can be a deuterium atom or a substituent substituted with a deuterium atom. For example, at least one of R1 to R4 can be a deuterium atom, an alkyl group having 1 to 20 carbon atoms substituted with a deuterium atom, an alkenyl group having 2 to 20 carbon atoms substituted with a deuterium atom, an aryl group having 6 to 30 carbon atoms for forming a ring substituted with a deuterium atom, or a heteroaryl group having 2 to 30 carbon atoms for forming a ring substituted with a deuterium atom. Further, in a case where the R1 group to the R4 group are plural, at least one of the plural R1 group to the R4 group can be a deuterium atom or a substituent substituted with a deuterium atom.

[0119] Formula 1 can be represented by any one of the following Formula 1A to Formula 1C:

[0120] Formula 1A

[0121]

[0122] Formula 1B

[0123]

[0124] Formula 1C

[0125]

[0126] In Formula 1A to Formula 1C, the same explanation as that of Formula 1 can be applied to Ar1 to Ar4, a to d, L1 to L4, and R1 to R4.

[0127] In the polycyclic compound of the embodiment represented by Formula 1A, any one of L2 and L4 can be a direct bond. For example, in the polycyclic compound of the embodiment represented by Formula 1A, L4 can be a direct bond, and L2 can be NRa. However, embodiments of the present inventive concept are not limited thereto.

[0128] Further, in the polycyclic compound of the embodiment represented by Formula 1B, any one of L2 to L4 can be a direct bond. For example, in the polycyclic compound of the embodiment represented by Formula 1B, L4 can be a direct bond, and L2 and L3 can be NRa. L2 and L3 can be the same as or different from each other. Meanwhile, embodiments of the present inventive concept are not limited thereto. L2 to L4 can each independently be one linker defined in Formula 1.

[0129] In the polycyclic compound of the embodiment represented by Formula 1C, any one of L1 and L4 can be a direct bond. For example, in the polycyclic compound of the embodiment represented by Formula 1C, L4 can be a direct bond, and L1 can be NRa. However, embodiments of the present inventive concept are not limited thereto.

[0130] In an embodiment, Formula 1 can be represented by the following Formula 1D:

[0131] Formula 1D

[0132]

[0133] In Formula 1D, the same explanation as that of Formula 1 can be applied to a to d, m1 to m4, L1 to L4, and R1 to R4.

[0134] In an embodiment, Formula 1 can be represented by any one of the following Formula 1-1 to Formula 1-4:

[0135] Formula 1-1

[0136]

[0137] Formula 1-2

[0138]

[0139] Formula 1-3

[0140]

[0141] Formula 1-4

[0142]

[0143] In Formulae 1-1 to 1-4, R 11 to R 17 , R 21 to R 25 , R 31 to R 36 , and R 41 to R 45 may each independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, R 11 to R 17 , R 21 to R 25 , R 31 to R 36 , and R 41 to R 45 may each independently be optionally linked to an adjacent group to form a ring.

[0144] In Formulae 1-1 to 1-4, x1 to x17 are each independently an integer of 0 to 4, and z1 to z5 are each independently an integer of 0 to 5.

[0145] In Formulae 1-1 to 1-4, W1 to W5 are each independently a direct bond, *-O-* or *-NRa-*. Meanwhile, Ra in NRa can be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a nitro group, a substituted or unsubstituted amine group, a substituted or unsubstituted oxy group, a substituted or unsubstituted thio group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, and W1 to W5 can each be optionally linked to an adjacent group to form a ring.

[0146] Further, in Formula 1-1, y1 can be an integer of 0 to 3.

[0147] The polycyclic compound of the embodiments contains a direct bond portion of a boron atom (B) and a nitrogen atom (N) (B-N bond), and aromatic rings forming the polycyclic compound are cross-linked to and fixed to each other due to the B-N bond, thereby improving the stability of the molecule of the polycyclic compound. Therefore, if the polycyclic compound of the embodiments is used as a material for an emission layer of an organic electroluminescent device, the lifetime characteristics of the organic electroluminescent device can be improved.

[0148] Further, the polycyclic compound of the embodiments further contains at least one boron atom not directly connected to a nitrogen atom in addition to the boron atom of the B-N bond, and a change in the skeleton of the molecule can be minimized even in the case of an excited state.

[0149] That is, the polycyclic compound of the embodiments has a molecular structure further containing at least one boron atom not directly connected to a nitrogen atom in addition to the boron atom of the B-N bond, and exhibits a low ΔE ST value. Therefore, the polycyclic compound can be used as a material for thermally activated delayed fluorescence (TADF), and exhibits a narrow full width at half maximum property in an emission wavelength region.

[0150] The polycyclic compound of the embodiments can be any one of the compounds represented in Compound Group 1. The organic electroluminescent device 10 of the embodiments can contain at least one of the polycyclic compounds represented in Compound Group 1 in an emission layer EML.

[0151] Compound Group 1

[0152]

[0153]

[0154]

[0155]

[0156] Meanwhile, in the polycyclic compound of the embodiments, at least one of the hydrogen atoms can be substituted with a deuterium atom. That is, the optional hydrogen atom in one molecule of the polycyclic compound according to the embodiments can be substituted with a deuterium atom.

[0157] For example, the polycyclic compound of the embodiments can include Compound 21-D shown below, which corresponds to Compound 21 in Compound Group 1, in which the hydrogen atom is partially substituted with a deuterium atom.

[0158]

[0159] Compound 21-D is an example, and the optional hydrogen atom in a molecule can be substituted with a deuterium atom in the polycyclic compound according to the embodiments represented in Compound Group 1.

[0160] The polycyclic compound of the embodiments can be used as a blue emission material. For example, the polycyclic compound according to the embodiments can be used as a light emitting material that emits blue light having a light emission center wavelength (λ 最大 ) in a wavelength region of about 470 nm or less than 470 nm. For example, the polycyclic compound of the embodiments can be a light emitting material having a light emission center wavelength in a wavelength region of about 430 nm to about 470 nm. The polycyclic compound of the embodiments represented by Formula 1 can be a blue thermally activated delayed fluorescence dopant.

[0161] The polycyclic compound of the embodiments can be a material for emitting thermally activated delayed fluorescence. The polycyclic compound of the embodiments provides aromatic rings connected to each other by a B-N bond, and can maintain a stable molecular structure and exhibit a narrow full width at half maximum during light emission. That is, the organic electroluminescent device of the embodiments includes the polycyclic compound of the embodiments in an emission layer, and can exhibit a long lifetime characteristic and excellent color reproducibility.

[0162] In the organic electroluminescent device 10 of the embodiments, the emission layer EML can emit delayed fluorescence. For example, the emission layer EML can emit thermally activated delayed fluorescence (TADF).

[0163] Meanwhile, although not shown in the drawings, the organic electroluminescent device 10 of the embodiments can include a plurality of emission layers. The plurality of emission layers can be laminated layer by layer and provided. For example, the organic electroluminescent device 10 including a plurality of emission layers can emit white light. The organic electroluminescent device including a plurality of emission layers can be an organic electroluminescent device having a tandem structure. If the organic electroluminescent device 10 includes a plurality of emission layers, at least one emission layer EML can include the polycyclic compound of the embodiments.

[0164] In the embodiments, the emission layer EML includes a host and a dopant, and can include the polycyclic compound of the embodiments as a dopant. For example, in the organic electroluminescent device 10 of the embodiments, the emission layer EML can include a host for emitting delayed fluorescence and a dopant for emitting delayed fluorescence, and can include the polycyclic compound as a dopant for emitting delayed fluorescence. The emission layer EML can include at least one of the polycyclic compound as a thermally activated delayed fluorescence dopant.

[0165] In the embodiments, the emission layer EML can be a delayed fluorescence emission layer, and the emission layer EML can include a known host material and the polycyclic compound described above. For example, in the embodiments, the polycyclic compound can be used as a TADF dopant.

[0166] Meanwhile, in an embodiment, the emission layer EML can include a known host material. For example, in an embodiment, the emission layer EML can include tris(8-hydroxyquinolinate)aluminum (Alq3), 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP), poly(N-vinylcarbazole) (PVK), 9,10-di(naphthalen-2-yl)anthracene (ADN), 4,4',4"-tris(carbazol-9-yl)-triphenylamine (TCTA), 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBi), 3-tert-butyl-9,10-di(naphthalen-2-yl)anthracene (TBADN), diphenylstyrylarylidene (DSA), 4,4'-bis(9-carbazolyl)-2,2'-dimethyl-biphenyl (CDBP), 2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN), bis2-(diphenylphosphoryl)phenyl ether oxide (DPEPO), hexaphenylcyclotriphosphazene (CP1), 1,4-bis(triphenylsilyl)benzene (UGH2), hexaphenylcyclotrisiloxane (DPSiO3), octaphenylcyclotetrasiloxane (DPSiO4), 2,8-bis(diphenylphosphoryl)dibenzo[b,d]furan (PPF), 3,3'-bis(N-carbazolyl)-1,1'-biphenyl (mCBP), 1,3-bis(N-carbazolyl)benzene (mCP), or the like as a host material. However, embodiments of the inventive concept are not limited thereto. Any known host material for emitting delayed fluorescence other than the suggested host materials can be included.

[0167] Meanwhile, in the organic electroluminescent device 10 of an embodiment, the emission layer EML can further include a known dopant material. In an embodiment, the emission layer EML can include a styryl derivative (e.g., 1,4-bis[2-(3-N-ethylcarbazolyl)vinyl]benzene (BCzVB), 4-(di-p-tolylamino)-4'-(di-p-tolylamino)styrylstilbene (DPAVB), and N-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl)naphthalen-2-yl)vinyl)phenyl)-N-phenylbenzenamine (N-BDAVBi)), perylene and derivatives thereof (e.g., 2,5,8,11-tetra-tert-butylperylene (TBP)), pyrene and derivatives thereof (e.g., 1,1-dipyrene, 1,4-dipyrenylbenzene, 1,4-bis(N,N-diphenylamino)pyrene), or the like as a dopant.

[0168] In the organic electroluminescent device 10 of an embodiment as shown in Figures 1 to 4 In the organic electroluminescent device 10 of an embodiment as shown in

[0169] The electronic transport region (ETR) can have a single layer formed using a single material, a single layer formed using multiple different materials, or a multi-layer structure with multiple layers formed using multiple different materials.

[0170] For example, the electron transport region (ETR) can have a single-layer structure of either the electron injection layer (EIL) or the electron transport layer (ETL), or a single-layer structure formed using an electron injection material and an electron transport material. Alternatively, the ETR can have a single-layer structure comprising multiple different materials, or a structure of electron transport layer (ETL) / electron injection layer (EIL) or hole blocking layer (HBL) / electron transport layer (ETL) / electron injection layer (EIL) laminated from the emitter layer (EML), but is not limited thereto. The thickness of the ETR can be, for example, approximately... to approximately

[0171] Various methods can be used to form the electron transport region (ETR) such as vacuum deposition, spin coating, tape casting, Langmuir-Blodgett (LB) method, inkjet printing, laser printing, and laser-induced thermal imaging (LITI).

[0172] If the electron transport region (ETR) includes an electron transport layer (ETL), the ETR can contain anthracene-based compounds. Examples of compounds that can contain tris(8-hydroxyquinoline)aluminum (Alq3), 1,3,5-tris(3-pyridyl)-benzene-3-ylbenzene, 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzimidazol-1-yl)phenyl)-9,10-dinaphthylanthracene, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), and 3-(4-biphenyl)-4-phenyl-5-tert-... Butylphenyl-1,2,4-triazole (TAZ), 4-(naphth-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD), bis(2-methyl-8-quinoline-N1,O8)-(1,1'-biphenyl-4-oxoline)aluminum (BAlq), bis(benzoquinoline-10-oxoline)beryllium (Bebq2), 9,10-bis(naphth-2-yl)anthracene (ADN), 1,3-bis[3,5-bis(pyridin-3-yl)phenyl]benzene (BmPyPhB), or mixtures thereof, but not limited thereto. The thickness of the electron transport layer (ETL) can be approximately to approximately And it can be, for example, about to approximately If the thickness of the electron transport layer ETL satisfies the range described above, satisfactory electron transport properties can be obtained without a significant increase in driving voltage.

[0173] If the electron transport region ETR includes an electron injection layer EIL, the electron injection layer EIL can include a metal halide (e.g., LiF, NaCl, CsF, RbCl, and RbI), a lanthanide metal (e.g., Yb), a metal oxide (e.g., Li2O and BaO), or lithium quinolate (LiQ). However, embodiments of the inventive concept are not limited thereto. A mixture material of an electron injection material and an insulating organic metal salt can also be used to form the electron injection layer EIL. The organic metal salt can be a material having a band gap of about 4 eV or greater than 4 eV. In particular, the organic metal salt can include, for example, a metal acetate, a metal benzoate, a metal acetylacetate, a metal acetylacetonate, or a metal stearate. The thickness of the electron injection layer EIL can be about 1 nm to about 10 nm. to about For example, about to about If the thickness of the electron injection layer EIL satisfies the range described above, satisfactory electron injection properties can be obtained without causing a significant increase in driving voltage.

[0174] The electron transport region ETR can include a hole blocking layer HBL as described above. The hole blocking layer HBL can include, for example, at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and 4,7-diphenyl-1,10-phenanthroline (Bphen). However, embodiments of the inventive concept are not limited thereto.

[0175] A second electrode EL2 is provided on the electron transport region ETR. The second electrode EL2 can be a common electrode or a cathode. The second electrode EL2 can be a transmissive electrode, a semi-transmissive and reflective electrode, or a reflective electrode. If the second electrode EL2 is a transmissive electrode, the second electrode EL2 can include a transparent metal oxide, for example, ITO, IZO, ZnO, ITZO, or the like.

[0176] If the second electrode EL2 is a semi-transmissive and reflective electrode or a reflective electrode, the second electrode EL2 can include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, a compound thereof, or a mixture thereof (e.g., a mixture of Ag and Mg). The second electrode EL2 can have a multi-layer structure including a reflective layer or a semi-transmissive and reflective layer formed using the materials described above, and a transparent conductive layer formed using ITO, IZO, ZnO, ITZO, or the like.

[0177] Although not shown, the second electrode EL2 can be connected with an auxiliary electrode. If the second electrode EL2 is connected with the auxiliary electrode, the resistance of the second electrode EL2 can be reduced.

[0178] Meanwhile, on the second electrode EL2 of the organic electroluminescent device 10 according to the embodiments, a capping layer CPL can be further provided. The capping layer CPL can include, for example, α-NPD, NPB, TPD, m-MTDATA, Alq3, CuPc, N4,N4,N4’,N4’-Tetrakis(3,5-dimethylphenyl)-N,N-biphenyl-4,4’-diamine (TPD15), 4,4’,4”-Tris(9H-carbazol-9-yl)-triphenylamine (TCTA), or the like.

[0179] The organic electroluminescent device 10 according to the embodiments of the inventive concept includes the polycyclic compound of the embodiments in an emission layer EML disposed between a first electrode EL1 and a second electrode EL2, thereby showing excellent emission efficiency and a narrow full width at half maximum in a blue light emission wavelength region. Further, the polycyclic compound according to the embodiments can emit thermally activated delayed fluorescence, and the emission layer EML can include the polycyclic compound of the embodiments to emit thermally activated delayed fluorescence and show a high emission efficiency property.

[0180] Meanwhile, the compound of the embodiments can be included in an organic layer other than the emission layer EML as a material for the organic electroluminescent device 10. For example, the organic electroluminescent device 10 according to the embodiments of the inventive concept can include the compound in at least one functional layer disposed between the first electrode EL1 and the second electrode EL2 or in a capping layer (CPL) disposed on the second electrode EL2.

[0181] The polycyclic compound of the embodiments has a combined structure by connecting a combination of an aromatic ring including a B-N direct bond moiety and at least one B not directly connected with N as a ring-forming heteroatom, and shows a high lowest triplet excited energy level, and thus can be used as a material for emitting delayed fluorescence. Further, the organic electroluminescent device of the embodiments including the polycyclic compound of the embodiments in the emission layer can emit blue light having a narrow full width at half maximum, and show a long lifetime property.

[0182] Hereinafter, the polycyclic compound according to the embodiments and the organic electroluminescent device of the embodiments of the inventive concept will be specifically explained with reference to the embodiments and comparative embodiments. The following embodiments are merely examples to help understanding of the inventive concept, and the scope of the inventive concept is not limited thereto.

[0183] Example

[0184] 1. Synthesis of the polycyclic compound of the embodiments

[0185] First, the synthesis method of the polycyclic compound according to the embodiment will be specifically explained with reference to the synthesis method of Compound 1. In addition, the synthesis method of the polycyclic compound explained below is only an embodiment, and the synthesis method of the polycyclic compound according to the embodiment of the inventive concept is not limited thereto.

[0186] (1) Synthesis of Compound 1

[0187] Compound 1 according to the embodiment can be synthesized, for example, by the steps of Reaction 1 below.

[0188] Reaction 1

[0189]

[0190] A solution of 3-bromoaniline (28.4 g) and methanol (800 ml) containing iodine monochloride (75 g) was stirred at room temperature for about 8 hours. The reaction solution was poured into water, and the target material was extracted with dichloromethane, dried with magnesium sulfate, and concentrated under reduced pressure. Then, the mixture thus obtained was separated by silica gel chromatography to obtain 31.0 g (yield 44%) of intermediate 1.

[0191] Then, 6N hydrochloric acid (300 ml) was added to the intermediate 1 (31 g) obtained in the above step, and then stirred. Then, the reaction solution was cooled to 0°C, stirred for about 1 hour while adding an aqueous solution (20 ml) containing sodium azide (7.3 g) dropwise, and then copper chloride (10.5 g) was added thereto. Then, the temperature of the reaction solution was raised to room temperature and stirred for about 1 hour. Stirring was again performed at about 60°C for about 30 minutes. Then, the reaction solution was cooled to room temperature, and the target material was extracted with dichloromethane. The organic layer was washed with sodium bicarbonate, dried with magnesium sulfate, and concentrated under reduced pressure. The mixture thus obtained was separated by silica gel chromatography to obtain 29.6 g (yield 94%) of intermediate 2.

[0192] Then, a solution of toluene (70 ml) containing intermediate 2 (6 g), diphenylamine (4.8 g), sodium butoxide (3.9 g), Pd2(dba)3(0.25 g), and XantPhos (0.3 g) was heated and refluxed under heating conditions in an oil bath for about 15 hours. Then, the reaction solution was cooled to room temperature, and then poured into water. The target material was extracted with toluene, dried with magnesium sulfate, and concentrated under reduced pressure. The mixture thus obtained was separated by silica gel chromatography to obtain 2.3 g (yield 32%) of intermediate 3.

[0193] A mixture containing intermediate 3 (2.3 g), 2,6-dichlorophenylboronic acid (1.3 g), potassium phosphate (3 g), and PdCl2(dppf) (65 mg) in toluene (20 ml), ethanol (10 ml), and water (10 ml) was heated and refluxed in an oil bath under heating conditions for about 3 hours. The reaction solution was cooled to room temperature, and then poured into water. The target material was extracted with toluene, dried over magnesium sulfate, and concentrated under reduced pressure. The mixture thus obtained was separated by silica gel chromatography to obtain 2.4 g (yield 90%) of intermediate 4.

[0194] A solution containing intermediate 4 (2.4 g) obtained in the above step, aniline (1.1 g), sodium butoxide (4 g), Pd2(dba)3(0.3 g), and PH(tBu)3 / BF4(0.4 g) in toluene (100 ml) was heated and refluxed in an oil bath under heating conditions for about 4 hours. Then, the reaction solution was cooled to room temperature, and then poured into water. The target material was extracted with ethyl acetate, dried over magnesium sulfate, and concentrated under reduced pressure. The mixture thus obtained was separated by silica gel chromatography to obtain 2 g (yield 70%) of intermediate 5.

[0195] A solution containing intermediate 5 (2 g) obtained in the above step in t-butylbenzene (60 ml) was cooled to about -78°C. t-BuLi / pentane solution (7 ml) was added thereto, followed by stirring at about 60°C for about 1 hour. Then, the reaction solution was cooled to about -35°C and 1M BBr3heptane solution (11 ml) was added dropwise thereto, followed by stirring at room temperature for about 3 hours. The solution was again cooled to about -40°C and diisopropylethylamine (2.5 ml) was added dropwise thereto, followed by heating and stirring at about 165°C for about 8 hours. The target material was extracted with ethyl acetate, dried over magnesium sulfate, and concentrated under reduced pressure. The mixture thus obtained was separated by silica gel chromatography to obtain 0.6 g (yield 30%) of compound 1 as the target material. In addition, it was found that the molecular weight of the target material was 694 by FAB-MS measurement. The target material thus obtained was purified again by sublimation and used as a sample for evaluation.

[0196] (2) Synthesis of compound 20

[0197] Compound 20 according to the embodiments can be synthesized, for example, by the steps described in Reaction 2 below:

[0198] Reaction 2

[0199]

[0200] The synthesis of compound 20 was performed by the same procedure as in the synthesis of compound 1, but using (2,6-dichloro-4-(di-p-tolylamino)-phenyl)boronic acid instead of 2,6-dichlorophenylboronic acid (1.3 g) added to intermediate 3 in the synthesis of compound 1. The molecular weight of the target material was found to be 889 by FAB-MS measurement. The target material thus obtained was purified again by sublimation and used as a sample for evaluation.

[0201] (3) Synthesis of compound 55

[0202] Compound 55 according to the embodiments can be synthesized, for example, by the steps described in Reaction 3 below:

[0203] Reaction 3

[0204]

[0205] A toluene (70 ml) solution containing intermediate 2 (6 g), diphenylamine (2.4 g), sodium butoxide (2.0 g), Pd2(dba)3(0.13 g), and XantPhos (0.15 g) was heated and refluxed under heating conditions in an oil bath for about 15 hours. The reaction solution was cooled to room temperature and then poured into water. The target material was extracted with toluene, dried over magnesium sulfate, and concentrated under reduced pressure. The mixture thus obtained was separated by silica gel chromatography to obtain 4.6 g (yield 70%) of intermediate 8.

[0206] A dioxane (15 ml) solution containing intermediate 8 (4.6 g) obtained in the above step, phenol (1.3 g), CuI (63 mg), Cs2CO3(6.2 g), and N,N-dimethylglycine (0.3 g) was heated and refluxed under heating conditions in an oil bath for about 15 hours. The reaction solution was cooled to room temperature and then poured into water. The target material was extracted with ethyl acetate, dried over magnesium sulfate, and concentrated under reduced pressure. The mixture thus obtained was separated by silica gel chromatography to obtain 2.8 g (yield 65%) of intermediate 9.

[0207] A toluene (20 ml), ethanol (10 ml), and water (10 ml) solution containing intermediate 9 (2.8 g) obtained in the above step, 2-chloro-4-(diphenylamino)phenylboronic acid (3.0 g), potassium phosphate (2.6 g), and PdCl2(dppf) (60 mg) was heated and refluxed under heating conditions in an oil bath for about 5 hours. The reaction solution was cooled to room temperature and then poured into water. The target material was extracted with toluene, dried over magnesium sulfate, and concentrated under reduced pressure. The mixture thus obtained was separated by silica gel chromatography to obtain 3.6 g (yield 89%) of intermediate 10.

[0208] A solution containing intermediate 10 (3.6 g) obtained in the above step, aniline (0.8 g), sodium butoxide (1.1 g), Pd2(dba)3(0.2 g), and PH(tBu)3 / BF4(0.3 g) in toluene (40 ml) was heated and refluxed under heating conditions in an oil bath for about 4 hours. The reaction solution was cooled to room temperature, and then poured into water. The target material was extracted with ethyl acetate, dried over magnesium sulfate, and concentrated under reduced pressure. The mixture thus obtained was separated by silica gel chromatography to obtain 2.9 g (yield 75%) of intermediate 11.

[0209] A solution containing intermediate 11 (2.9 g) obtained in the above step in t-butylbenzene (60 ml) was cooled to about -78°C. t-BuLi / pentane solution (about 1.9 mol / L, 5 ml) was added thereto, followed by stirring at about 60°C for about 1 hour. Then, the reaction solution was cooled to about -35°C and 1M BBr3heptane solution (10 ml) was added dropwise thereto, followed by stirring at room temperature for about 3 hours. The solution was again cooled to about -40°C and diisopropylethylamine (2.5 ml) was added dropwise thereto, followed by heating and stirring at about 165°C for about 8 hours. The reaction mixture was cooled back to room temperature, and then poured into soda water. The target material was extracted with ethyl acetate, dried over magnesium sulfate, and concentrated under reduced pressure. The mixture thus obtained was separated by silica gel chromatography to obtain 0.7 g (yield 25%) of compound 55 as the target material. In addition, the molecular weight of the target material was found to be 687 by FAB-MS measurement. The target material thus obtained was purified again by sublimation and used as a sample for evaluation.

[0210] 2. Manufacture and evaluation of organic electroluminescent device

[0211] Evaluation of the emission properties of the organic electroluminescent device of the embodiment of the polycyclic compound and the polycyclic compound comprising the embodiment in the emission layer was performed by the method described below. The method of manufacturing the organic electroluminescent device for device evaluation is described below.

[0212] The organic electroluminescent devices of Example 1 to Example 3 were manufactured using the polycyclic compound of compound 1, compound 20, and compound 55, respectively, as a dopant material for the emission layer. The organic electroluminescent devices of Comparative Example 1 to Comparative Example 3 were manufactured using comparative compound C1, comparative compound C2, and comparative compound C3, respectively, as a dopant material for the emission layer.

[0213] The compounds used for Example 1 to Example 3 and Comparative Example 1 to Comparative Example 3 are shown in the following Table 1.

[0214] Table 1

[0215]

[0216]

[0217] Manufacture of organic electroluminescent device

[0218] On a glass substrate, ITO was patterned to have a thickness of about 150 nm and washed with ultrapure water, cleaned with ultrasonic waves, exposed to UV for about 30 minutes, and treated with ozone. Then, HAT-CN was deposited to a thickness of about 1 nm, α-NPD was deposited to a thickness of about 20 nm, and mCP was deposited to a thickness of about 30 nm, thereby forming a hole transport zone.

[0219] Then, the polycyclic compound of the embodiment or the comparative compound and the host material were co-deposited at a ratio of 6:94 to form a layer to a thickness of about 10 nm, thereby forming an emission layer. That is, the formation of the emission layer by co-deposition was performed by mixing Compound 1, Compound 20, and Compound 55 with the host material, respectively, and depositing in Example 1 to Example 3, or by mixing Comparative Compound C1, Comparative Compound C2, and Comparative Compound C3 with the host material, respectively, and depositing in Comparative Example 1 to Comparative Example 3. During the formation of the emission layer, mCP was used as the host material.

[0220] Thereafter, on the emission layer, a layer having a thickness of about 30 nm was formed using DPEPO, a layer having a thickness of about 10 nm was formed using TPBi, and a layer having a thickness of about 1 nm was formed using Liq, thereby forming an electron transport zone. Then, a second electrode having a thickness of about 150 nm was formed using aluminum (Al).

[0221] The hole transport zone, the emission layer, the electron transport zone, and the second electrode were formed using a vacuum deposition apparatus.

[0222] Evaluation of properties of organic electroluminescent device

[0223] In Table 2, evaluation results of the organic electroluminescent devices of Example 1 to Example 3 and Comparative Example 1 to Comparative Example 3 are shown. In Table 2, the maximum emission wavelength (λ 最大 ), the full width at half maximum (FWHM) in the emission wavelength region, the emission efficiency, and the device lifetime of the organic electroluminescent devices thus manufactured are compared and shown. In the evaluation results of the properties of the examples and comparative examples shown in Table 2, the maximum emission wavelength (λ 最大 ​​​​​​​​​) indicates a wavelength showing a maximum value in an emission spectrum, and the emission efficiency indicates an external quantum efficiency measured at a luminance of 100 cd / m 2

[0224] Table 2

[0225] Classification Dopant material 最大 (nm) ​ Full width at half maximum Emission efficiency Device lifetime Example 1 Compound 1 469 nm 23 nm 15.5％ 165％ Example 2 Compound 20 465 nm 28 nm 17.8％ 158％ Example 3 Compound 55 462 nm 26 nm 21.5％ 135％ Comparative Example 1 Comparative compound C1 459 nm 30 nm 5％ 100％ Comparative Example 2 Comparative compound C2 446 nm 23 nm 8％ 105％ Comparative Example 3 Comparative compound C3 538 nm 63 nm 18.5％ 130％

[0226] Referring to the results of Table 2, it is confirmed that the organic electroluminescent devices of Example 1 to Example 3 emit light in a blue wavelength region of about 470 nm or less than 470 nm and light having a narrow full width at half maximum of less than about 30 nm. In addition, the organic electroluminescent devices of Example 1 to Example 3 including the polycyclic compound according to the embodiments show excellent emission efficiency properties and excellent device lifetime characteristics.

[0227] In contrast, Comparative Example 1 shows a full width at half maximum of about 30 nm and emits light in a blue wavelength region, but has lower emission efficiency and device lifetime characteristics when compared with the examples. In Comparative Example 2, a cross-linking structure that binds to each other via an aromatic ring is shown, showing emission properties having a relatively narrow full width at half maximum, but the device lifetime of the examples is better. In addition, Comparative Example 3 uses Comparative Compound C3, which is a polycyclic compound having a structure including a B-N direct bond, but unlike the examples, it has a structure not including an additional B atom, and emits light in a wavelength region longer than the light emission wavelength region of the examples, and shows a large full width at half maximum.

[0228] The polycyclic compound of the embodiments includes a B-N direct bond moiety and has a structure in which aromatic rings bind to each other, including at least one B atom not directly bound to an N atom. Therefore, the molecular structure is stable even in an excited state, and can show emission properties having a narrow full width at half maximum, and long lifetime characteristics of a device can be achieved. In addition, the organic electroluminescent device of the embodiments includes the polycyclic compound of the embodiments in an emission layer, and shows a narrow full width at half maximum in a light emission wavelength region, thereby showing excellent color properties and improved lifetime characteristics.

[0229] The organic electroluminescent device of the embodiments can show device properties having improved lifetime characteristics.

[0230] In addition, the organic electroluminescent device of the embodiments can emit blue light having a narrow full width at half maximum.

[0231] The polycyclic compound of the embodiments is included in an emission layer of an organic electroluminescent device and can contribute to increasing the lifetime of the organic electroluminescent device.

[0232] ​While exemplary embodiments of the application have been described, it is to be understood that the application is not to be limited to those embodiments but is applicable to any alterations and modifications as falling within the aims and scope of the application as claimed.

Claims

1. An organic electroluminescent device comprising: a first electrode; a second electrode provided on the first electrode; and an emission layer provided between the first electrode and the second electrode and containing at least one polycyclic compound, wherein the first electrode and the second electrode each independently contain: one selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn; a compound of two or more selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn; a mixture of two or more selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn; or an oxide of one selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn, and wherein the at least one polycyclic compound is selected from the compounds represented by Formula 1-1 and Formula 1-2: Formula 1-1 Formula 1-2 in Formula 1-1, y1 is an integer of 0 to 3, in Formula 1-1 and Formula 1-2, x1 to x8 are each independently an integer of 0 to 4, R 11 to R 17 and R 21 to R 25 each independently is a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted arylamine group having 6 to 30 carbon atoms for ring formation, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for ring formation, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for ring formation, and R 11 to R 17 and R 21 to R 25 each independently is optionally linked to an adjacent group to form a ring, z1 to z3 are each independently an integer of 0 to 5, each Ra is independently a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for ring formation, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for ring formation, and each Ra is independently optionally linked with an adjacent group to form a ring, W1is a direct bond, or and wherein the "substitution" means substitution with at least one of a deuterium atom, a halogen atom, a cyano group, a nitro group, an amino group, and an alkyl group having 1 to 10 carbon atoms. 2.An organic electroluminescent device comprising: a first electrode; a second electrode provided on the first electrode; and an emission layer provided between the first electrode and the second electrode, ​ ​ wherein the first electrode and the second electrode each independently comprise: one selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn; a compound of two or more selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn; a mixture of two or more selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn; or an oxide of one selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn, and wherein the emission layer comprises at least one polycyclic compound of Compound Group 1: Compound Group 1 。 3. The organic electroluminescent device according to claim 1 or 2, wherein the emission layer emits delayed fluorescence.

4. The organic electroluminescent device according to claim 1 or 2, wherein the emission layer comprises a host and a dopant, and the dopant comprises the polycyclic compound.

5. The organic electroluminescent device according to claim 1 or 2, wherein the emission layer emits light having a center wavelength of 430 nm to 470 nm.

6. The organic electroluminescent device according to claim 1 or 2, wherein the first electrode and the second electrode each independently comprise an oxide of two or more selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn.

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