Organic electroluminescent device and polycyclic compound for organic electroluminescent device

Abstract

To provide an organic electroluminescent element exhibiting excellent luminous efficacy, and a polycyclic compound that is a material for an organic electroluminescent element.SOLUTION: A luminous layer includes a polycyclic compound represented by the following chemical formula 1. In the following chemical formula 1, Y1, Y2, and Y3 are each independently *-NRa-*, *-O-*, or *-S-*. Chemical formula 1.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an organic electroluminescent device and a polycyclic compound used therein, and more particularly to a polycyclic compound used as a light-emitting material and an organic electroluminescent device containing the same. [Background technology]

[0002] Recently, organic electroluminescence displays (OLEDs) have been actively developed as image display devices. Unlike liquid crystal displays, OLEDs are so-called self-luminous displays that realize display by recombining holes and electrons injected from a first electrode and a second electrode in a light-emitting layer to cause a light-emitting material containing an organic compound in the light-emitting layer to emit light.

[0003] In order to apply organic electroluminescent devices to display devices, there is a demand for lower driving voltages, higher luminous efficiency, and longer life for the organic electroluminescent devices, and there is a continuous demand for the development of materials for organic electroluminescent devices that can stably achieve these demands.

[0004] In particular, in order to realize highly efficient organic electroluminescent devices, technologies related to phosphorescence emission that utilizes the energy of triplet states and delayed fluorescence emission that utilizes the phenomenon in which singlet excitons are generated by the collision of triplet excitons (TTA) have been developed recently, and development is also underway on thermally activated delayed fluorescence (TADF) materials that utilize the delayed fluorescence phenomenon. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Korean Patent Publication No. 2010-0048447 [Patent Document 2] JP 2010-012696 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide an organic electroluminescent device that exhibits excellent luminous efficiency.

[0007] Another object of the present invention is to provide a polycyclic compound which is a material for an organic electroluminescent device having high efficiency characteristics. [Means for solving the problem]

[0008] According to one embodiment, there is provided a polycyclic compound represented by the following Chemical Formula 1: [ka] ...(chemical formula 1) In Chemical Formula 1, A1, A2, and A3 are each independently a substituted or unsubstituted hydrocarbon ring having 5 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycle having 2 to 30 ring carbon atoms, X1, X2, and X3 are each independently a substituted or unsubstituted hydrocarbon ring having 5 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycle having 2 to 30 ring carbon atoms, and Y1, Y2, and Y3 are each independently *-NRa-*, *-O-*, or *-S-*. Ra is a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms.

[0009] A1, A2, and A3 may each independently be an unsubstituted benzene ring or a benzene ring substituted with at least one substituent, and the at least one substituent may be a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms, or a substituted or unsubstituted amino group.

[0010] X1, X2, and X3 each independently may be a benzene ring substituted with at least one of a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms, and a substituted or unsubstituted amino group.

[0011] Chemical Formula 1 may be represented by Chemical Formula 2 below. [ka] ...(chemical formula 2) In Chemical Formula 2, R 1 ~R 18 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms, or a substituted or unsubstituted amino group, and Y1, Y2, and Y3 are as defined in Chemical Formula 1 above.

[0012] Y1, Y2, and Y3 may all be the same.

[0013] At least one of Y1, Y2, and Y3 may be *-NRa-*, and the rest may be *-O-* or *-S-*.

[0014] The polycyclic compound represented by Chemical Formula 1 may be a blue dopant that emits blue light having a central wavelength of 470 nm or less.

[0015] The lowest triplet excited energy level (T 1 The level may be greater than 2.6 eV.

[0016] The polycyclic compound represented by Chemical Formula 1 may be a thermally activated delayed fluorescent material.

[0017] According to another embodiment, there is provided an organic electroluminescent device including a first electrode, a second electrode disposed on the first electrode, and an emitting layer disposed between the first electrode and the second electrode and including the polycyclic compound according to the above-described embodiment.

[0018] The light-emitting layer may emit delayed fluorescence.

[0019] The light-emitting layer may include a host and a dopant, and the dopant may include the polycyclic compound.

[0020] The light emitting layer may emit light having a central wavelength of 430 nm or more and 470 nm or less. Effect of the Invention

[0021] An organic electroluminescent device according to an embodiment exhibits improved device characteristics with high efficiency in the blue wavelength region.

[0022] The polycyclic compound according to one embodiment is contained in the light-emitting layer of an organic electroluminescent device, thereby contributing to improving the efficiency of the organic electroluminescent device. [Brief description of the drawings]

[0023] [Figure 1] 1 is a cross-sectional view illustrating an organic electroluminescent device according to an embodiment of the present invention. [Diagram 2] 1 is a cross-sectional view illustrating an organic electroluminescent device according to an embodiment of the present invention. [Diagram 3] 1 is a cross-sectional view illustrating an organic electroluminescent device according to an embodiment of the present invention. [Figure 4] 1 is a cross-sectional view illustrating an organic electroluminescent device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Since the present invention can be modified in various ways and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text, but it is not intended to limit the present invention to the specific disclosed forms, but it should be understood that the present invention includes all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0025] As used herein, when a component (or region, layer, portion, etc.) is referred to as being "on" or "coupled" to another component, it means that it may be directly disposed, coupled, or connected to the other component, or that a third component may be disposed therebetween.

[0026] The same reference numerals refer to the same components. Also, in the drawings, thickness, proportions, and dimensions of components may be exaggerated for the purpose of effectively explaining technical contents.

[0027] "And / or" includes all combinations of one or more of the associated construct.

[0028] Terms such as first and second are used to describe various components, but the components are not limited to these terms. The terms are used only to distinguish one component from another. For example, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component, without departing from the scope of the present invention. A singular expression includes a plural expression, unless the context clearly indicates otherwise.

[0029] In addition, terms such as "under", "below", "up" and "above" are used to describe the relative relationship of components shown in the drawings. These terms are relative concepts and are described based on the directions shown in the drawings.

[0030] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Furthermore, terms such as those defined in commonly used dictionaries should be interpreted to have a meaning consistent with the meaning in the context of the relevant art, and are expressly defined herein, unless interpreted in an idealized or overly formal sense.

[0031] It should be understood that terms such as "comprise" or "have" specify the presence of any feature, numeral, step, operation, component, part, or combination thereof set forth in the specification above, but do not preclude the presence or additional possibility of one or more other features, numerals, steps, operations, components, parts, or combinations thereof.

[0032] In this specification, "substituted or unsubstituted" means that it is substituted with one or more substituents selected from the group consisting of a deuterium atom, a halogen atom, a cyano group, a nitro group, an amino group, a silyl group, an oxy group, a thio group, a sulfinyl group, a sulfonyl group, a carbonyl group, a boron group, a phosphine oxide group, a phosphine sulfide group, an alkyl group, an alkenyl group, an alkoxy group, a hydrocarbon ring group, an aryl group, and a heterocyclic group, or is unsubstituted. In addition, each of the above-mentioned exemplary substituents may be substituted or unsubstituted. For example, a biphenylyl group may be interpreted as an aryl group, or as a phenyl group substituted with a phenyl group.

[0033] In this specification, "adjacent groups bond together to form a ring" means adjacent groups bond together to form a substituted or unsubstituted hydrocarbon ring, or a substituted or unsubstituted heterocycle. Hydrocarbon rings include aliphatic hydrocarbon rings and aromatic hydrocarbon rings. Heterocyclic groups include aliphatic heterocyclic groups and aromatic heterocyclic groups. The ring formed by bonding adjacent groups together is a monocycle or polycycle. In addition, the ring formed by bonding together may be bonded to another ring to form a spiro structure.

[0034] In this specification, the term "adjacent group" refers to a substituent substituted on an atom directly bonded to the atom on which the corresponding substituent is substituted, another substituent substituted on an atom on which the corresponding substituent is substituted, or a substituent that is sterically most adjacent to the corresponding substituent. For example, two methyl groups in 1,2-dimethylbenzene are interpreted as "adjacent groups" to each other, and two ethyl groups in 1,1-diethylcyclopentene are interpreted as "adjacent groups" to each other.

[0035] In this specification, examples of halogen atoms include a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

[0036] In this specification, an alkyl group is linear, branched, or cyclic. The number of carbon atoms in an alkyl group is 1 to 50, 1 to 30, 1 to 20, 1 to 10, or 1 to 6. Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, t-butyl, i-butyl, 2-ethylbutyl, 3,3-dimethylbutyl, n-pentyl, i-pentyl, neopentyl, t-pentyl, cyclopentyl, 1-methylpentyl, 3-methylpentyl, 2-ethylpentyl, 4-methyl-2-pentyl, n-hexyl, 1-methylhexyl ...3,3-dimethylbutyl, n-pentyl, i-pentyl, neopentyl, t-pentyl, cyclopentyl, 3,3-dimethylbutyl, n-pentyl, i-pentyl, i-pentyl, i-pentyl, i-pentyl, i-pentyl, i-pentyl, i-pentyl, i-pentyl, i-pentyl, i-pentyl, i-pentyl, i-pentyl, Hexyl, 2-butylhexyl, cyclohexyl, 4-methylcyclohexyl, 4-t-butylcyclohexyl, n-heptyl, 1-methylheptyl, 2,2-dimethylheptyl, 2-ethylheptyl, 2-butylheptyl, n-octyl, t-octyl, 2-ethyloctyl, 2-butyloctyl, 2-hexyloctyl, 3,7-dimethyloctyl, cyclooctyl, n-nonyl, n-decyl, adamantyl n-butyldecyl, 2-ethyldecyl, 2-butyldecyl, 2-hexyldecyl, 2-octyldecyl, n-undecyl, n-dodecyl, 2-ethyldodecyl, 2-butyldodecyl, 2-hexyldodecyl, 2-octyldecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, 2-ethylhexadecyl, 2-butylhexadecyl, 2-hexylhexadecyl, 2-octylhexadecyl , n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n-icosyl group, 2-ethylicosyl group, 2-butylicosyl group, 2-hexylicosyl group, 2-octylicosyl group, n-henicosyl group, n-docosyl group, n-tricosyl group, n-tetracosyl group, n-pentacosyl group, n-hexacosyl group, n-heptacosyl group, n-octacosyl group, n-nonacosyl group, and n-triacontyl group, but are not limited to these.

[0037] In the present specification, the hydrocarbon ring is an aliphatic or aromatic hydrocarbon ring having 5 to 60, 5 to 30, or 5 to 20 ring carbon atoms. The hydrocarbon ring group is any functional group or substituent derived from an aliphatic hydrocarbon ring, or any functional group or substituent derived from an aromatic hydrocarbon ring. The number of ring carbon atoms of the hydrocarbon ring group is 5 to 60, 5 to 30, or 5 to 20.

[0038] In this specification, the aryl group means any functional group or substituent derived from an aromatic hydrocarbon ring. The aryl group is a monocyclic aryl group or a polycyclic aryl group. The number of ring carbon atoms of the aryl group is 6 to 30, 6 to 20, or 6 to 15. Examples of the aryl group include, but are not limited to, a phenyl group, a naphthyl group, a fluorenyl group, an anthracenyl group, a phenanthryl group, a biphenylyl group, a terphenylyl group, a quaterphenylyl group, a quinquephenylyl group, a sexiphenyl group, a triphenylenyl group, a pyrenyl group, a benzofluoranthenyl group, and a chrysenyl group.

[0039] In this specification, a heterocyclic group refers to any functional group or substituent derived from a ring containing one or more of B, O, N, P, Si, and S as heteroatoms. Heterocyclic groups include aliphatic heterocyclic groups and aromatic heterocyclic groups. Aromatic heterocyclic groups are heteroaryl groups. The aliphatic heterocycles and aromatic heterocycles are monocyclic or polycyclic.

[0040] In this specification, the heterocycle includes one or more of B, O, N, P, Si, and S as a heteroatom. If the heterocycle includes two or more heteroatoms, the two or more heteroatoms may be the same or different. The heterocycle may be a monocyclic heterocycle or a polycyclic heterocycle, and includes a heteroaryl ring. The number of ring carbon atoms of the heterocycle is 2 to 30, 2 to 20, or 2 to 10.

[0041] In this specification, an aliphatic heterocyclic group contains one or more heteroatoms selected from B, O, N, P, Si, and S. The number of ring carbon atoms in the aliphatic heterocyclic group is 2 to 30, 2 to 20, or 2 to 10. Examples of the aliphatic heterocyclic group include, but are not limited to, an oxiranyl group, a thiiranyl group, a pyrrolidinyl group, a piperidinyl group, a tetrahydrofuranyl group, a tetrahydrothiophenyl group, a thianyl group, a tetrahydropyranyl group, and a 1,4-dioxanyl group.

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

[0043] In this specification, the number of carbon atoms of the amino group is not particularly limited, but is 1 to 30. The amino group includes an alkylamino group and an arylamino group. Examples of the amino group include, but are not limited to, a methylamino group, a dimethylamino group, a phenylamino group, a diphenylamino group, a naphthylamino group, a 9-methyl-anthracenylamino group, and a triphenylamino group. For example, the alkyl group of the alkylamino group may be the same as the above-mentioned examples of the alkyl group, and the aryl group of the arylamino group may be the same as the above-mentioned examples of the aryl group.

[0044] In this specification, a direct linkage means a single bond.

[0045] In addition, in this specification, "-*" indicates the position of attachment.

[0046] Hereinafter, an organic electroluminescent device according to an embodiment of the present invention and a polycyclic compound included therein according to an embodiment will be described with reference to the drawings.

[0047] 1 to 4 are cross-sectional views each showing a schematic configuration of an organic electroluminescent device according to an embodiment of the present invention. Referring to Fig. 1 to Fig. 4, in an organic electroluminescent device 10 according to an embodiment of the present invention, a first electrode EL1 and a second electrode EL2 are disposed facing each other, and an emission layer EML is disposed between the first electrode EL1 and the second electrode EL2.

[0048] The organic electroluminescent device 10 according to an embodiment further includes a plurality of functional layers between the first electrode EL1 and the second electrode EL2 in addition to the emission layer EML. The plurality of functional layers include a hole transport region HTR and an electron transport region ETR. That is, the organic electroluminescent device 10 according to an embodiment of the present invention includes a first electrode EL1, a hole transport region HTR, an emission layer EML, an electron transport region ETR, and a second electrode EL2, which are stacked in sequence. The organic electroluminescent device 10 according to an embodiment of the present invention may also include a capping layer CPL disposed on the second electrode EL2.

[0049] The organic electroluminescent device 10 according to an embodiment includes a polycyclic compound according to an embodiment of the present invention, which will be described later, in an emission layer EML disposed between the first electrode EL1 and the second electrode EL2. However, the embodiment is not limited thereto, and the organic electroluminescent device 10 according to an embodiment may include a polycyclic compound according to an embodiment of the present invention, which will be described later, in a hole transport region HTR or an electron transport region ETR, which are multiple functional layers disposed between the first electrode EL1 and the second electrode EL2, in addition to the emission layer EML.

[0050] Meanwhile, unlike Fig. 1, Fig. 2 shows a cross-sectional view of an organic electroluminescent device 10 according to an embodiment in which the hole transport region HTR includes a hole injection layer HIL and a hole transport layer HTL, and the electron transport region ETR includes an electron injection layer EIL and an electron transport layer ETL. Also, unlike Fig. 1, Fig. 3 shows a cross-sectional view of an organic electroluminescent device 10 according to an embodiment in which the hole transport region HTR includes a hole injection layer HIL, a hole transport layer HTL, and an electron blocking layer EBL, and the electron transport region ETR includes an electron injection layer EIL, an electron transport layer ETL, and a hole blocking layer HBL. Unlike Fig. 2, Fig. 4 shows a cross-sectional view of an organic electroluminescent device 10 according to an embodiment including a capping layer CPL disposed on the second electrode EL2.

[0051] The first electrode EL1 has conductivity. The first electrode EL1 is made of a metal alloy or a conductive compound. The first electrode EL1 may be an anode. The first electrode EL1 may also be a pixel electrode. The first electrode EL1 is a transmissive electrode, a semi-transmissive electrode, or a reflective electrode. If the first electrode EL1 is a transmissive electrode, the first electrode EL1 includes a transparent metal oxide, for example, ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), ITZO (indium tin zinc oxide), etc. If the first electrode EL1 is a semi-transmissive electrode or a reflective electrode, the first electrode EL1 includes Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, or a compound or mixture thereof (for example, an alloy of Ag and Mg). The first electrode EL1 may have a multi-layer structure including a reflective film or semi-transparent film made of the above-mentioned material, and a transparent conductive film made of ITO, IZO, ZnO, ITZO, etc. For example, the first electrode EL1 may have a triple-layer structure of ITO / Ag / ITO, but is not limited thereto. The thickness of the first electrode EL1 may be about 100 nm to about 1000 nm, for example, about 100 nm to about 300 nm.

[0052] The hole transport region HTR is provided on the first electrode EL1. The hole transport region HTR may 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 may be, for example, about 5 nm to about 150 nm.

[0053] The hole transport region HTR may have a single layer of a single material, a single layer of a plurality of different materials, or a multi-layer structure having a plurality of layers of a plurality of different materials.

[0054] For example, the hole transport region HTR may have a single layer structure of a hole injection layer HIL or a hole transport layer HTL, or a single layer structure of a hole injection material and a hole transport material. The hole transport region HTR may have a single layer structure of a plurality of different materials, or a structure of a hole injection layer HIL / hole transport layer HTL, a hole injection layer HIL / hole transport layer HTL / hole buffer layer (not shown), a hole injection layer HIL / hole buffer layer (not shown), a hole transport layer HTL / hole buffer layer, or a hole injection layer HIL / hole transport layer HTL / electron blocking layer EBL, which are stacked in order from the first electrode EL1, but the embodiment is not limited thereto.

[0055] 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).

[0056] The hole injection layer HTL may be, for example, a phthalocyanine compound such as copper phthalocyanine, DNTPD (N,N'-diphenyl-N,N'-bis-[4-phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4'-diamine), m-MTDATA (4,4',4"-[tris(3-methylphenyl)phenylamino]triphenylamine), TDATA (4,4',4"-tris(N,N-diphenylamino)triphenylamine), 2-TNATA (4,4',4"-tris{N,-(2-naphthyl)-N-phenylamino}-triphenylamine), PEDOT / PSS (poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonyl)sulfonyl) polyaniline / poly(4-styrenesulfonate)), PANI / DBSA (polyaniline / dodecylbenzenesulfonic acid), PANI / CSA (polyaniline / camphorsulfonic acid), PANI / PSS (polyaniline / poly(4-styrenesulfonate)), NPB (N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine), polyether ketone with triphenylamine (TPAPEK), 4-isopropyl-4'-methyldiphenyliodonium [tetrakis(pentafluorophenyl)borate], HAT-CN (dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile), and the like.

[0057] The hole transport layer HTL may include, for example, a carbazole derivative such as N-phenylcarbazole or polyvinylcarbazole, a fluorene derivative, a triphenylamine derivative such as TPD (N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1-biphenyl]-4,4'-diamine) or TCTA (4,4',4"-tris(N-carbazolyl)triphenylamine), NPB (N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine), TAPC (4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzeneamine]), HMTPD (4,4'-bis[N,N'-(3-tolyl)amino]-3,3'-dimethylbiphenyl), or mCP (1,3-bis(N-carbazolyl)benzene).

[0058] The thickness of the hole transport region HTR may be about 5 nm to about 1000 nm, for example, about 10 nm to about 500 nm. The thickness of the hole injection layer HIL may be, for example, about 3 nm to about 100 nm, and the thickness of the hole transport layer HTL may be about 3 nm to about 100 nm. For example, the thickness of the electron blocking layer EBL may be about 1 nm to about 100 nm. When the thicknesses of the hole transport region HTR, the hole injection layer HIL, the hole transport layer HTL, and the electron blocking layer EBL satisfy the above-mentioned ranges, sufficient hole transport properties can be obtained without a substantial increase in driving voltage.

[0059] In addition to the above-mentioned materials, the hole transport region HTR may further include a charge generating material to improve conductivity. The charge generating material may be uniformly or non-uniformly distributed in the hole transport region HTR. The charge generating material is, for example, a p-dopant. The p-dopant may be one of, but is not limited to, a quinone derivative, a metal oxide, and a cyano group-containing compound. For example, examples of the p-dopant include, but are not limited to, quinone derivatives such as TCNQ (tetracyanoquinodimethane) and F4-TCNQ (2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanoquinodimethane), and metal oxides such as tungsten oxide and molybdenum oxide.

[0060] As described above, the hole transport region HTR may further include at least one of a hole buffer layer (not shown) and an electron blocking layer EBL in addition to the hole injection layer HIL and the hole transport layer HTL. The hole buffer layer (not shown) compensates for the resonance distance according to the wavelength of light emitted from the emission layer EML to increase light emission efficiency. The material contained in the hole buffer layer (not shown) may be a material that may be contained in the hole transport region HTR. The electron blocking layer EBL is a layer that serves to prevent the injection of electrons from the electron transport region ETR to the hole transport region HTR.

[0061] The light-emitting layer EML is provided on the hole transport region HTR. The light-emitting layer EML has a thickness of, for example, about 10 nm to about 100 nm, or about 10 nm to about 30 nm. The light-emitting layer EML has a multilayer structure having a single layer made of a single material, a single layer made of a plurality of different materials, or a plurality of layers made of a plurality of different materials.

[0062] In the organic electroluminescent device 10 according to an embodiment, the emission layer EML contains a polycyclic compound according to an embodiment described below.

[0063] The emission layer EML of the organic electroluminescent device 10 according to an embodiment includes a polycyclic compound represented by Chemical Formula 1 below according to an embodiment. [ka] ...(chemical formula 1)

[0064] In Chemical Formula 1, A1, A2, and A3 are each independently a substituted or unsubstituted hydrocarbon ring having from 5 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycle having from 2 to 30 ring carbon atoms. For example, A1, A2, and A3 may each independently be a substituted or unsubstituted aryl group having from 5 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms.

[0065] When A1, A2, and A3 are each independently a substituted hydrocarbon ring or a substituted heterocycle, the substituent is a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, or a substituted or unsubstituted amino group. Here, the amino group is an alkylamino group or an arylamino group. The amino group may be an alkylamino group having 1 to 20 carbon atoms, or an arylamino group having 6 to 30 carbon atoms.

[0066] As described above, A1, A2, and A3 are each independently a substituted or unsubstituted hydrocarbon ring having 5 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycle having 2 to 30 ring carbon atoms.

[0067] In one embodiment, A1, A2, and A3 may each independently be an unsubstituted benzene ring or a benzene ring substituted with at least one substituent. In the case of a substituted benzene ring, the at least one substituent may be a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, or a substituted or unsubstituted amino group.

[0068] In Chemical Formula 1, X1, X2, and X3 are each independently a substituted or unsubstituted hydrocarbon ring having from 5 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycle having from 2 to 30 ring carbon atoms. For example, X1, X2, and X3 may each independently be a substituted or unsubstituted aryl group having from 5 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms.

[0069] In one embodiment, X1, X2, and X3 may each independently be an unsubstituted benzene ring or a benzene ring substituted with at least one substituent. For example, X1, X2, and X3 may each independently be an unsubstituted benzene ring substituted with at least one of a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, and a substituted or unsubstituted amino group.

[0070] In one embodiment, X1, X2, and X3 may be the same or at least one may be different. For example, when at least one of X1, X2, and X3 is different, at least one of the substituents substituted on the ring of X1, X2, and X3 may be different from each other.

[0071] In Chemical Formula 1, Y1, Y2, and Y3 are each independently *-NRa-*, *-O-*, or *-S-*. Ra is a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms.

[0072] That is, the polycyclic compound according to one embodiment is provided in a fixed state in which rings such as A1, A2, and A3 and rings such as X1, X2, and X3 are bonded to each other by Y1, Y2, and Y3, each of which is represented by any one of *-NRa-*, *-O-*, and *-S-*. That is, the polycyclic compound according to one embodiment is provided in a fused ring form in which adjacent rings are bonded to each other by Y1, Y2, and Y3, each of which is a linker containing a heteroatom.

[0073] In one embodiment, Y1, Y2, and Y3 may all be the same. Also, in one embodiment, at least one of Y1, Y2, and Y3 may be *-NRa-*, and the rest may be *-O-* or *-S-*.

[0074] The polycyclic compound according to an embodiment, in which adjacent rings are bonded to each other and fixed by Y1, Y2, and Y3, etc., exhibits a high lowest triplet excitation energy level (T1 level), which facilitates reverse intersystem crossing. For example, the lowest triplet excitation energy level (T1 level) of the polycyclic compound according to an embodiment may be greater than 2.6 eV.

[0075] The polycyclic compound according to one embodiment is provided in a form in which polycyclic aromatic rings containing B (boron) or N (nitrogen) as ring-forming atoms are bonded to each other via *-NRa-*, *-O-*, or *-S-*, etc., and has a central emission wavelength λ in the wavelength region of 470 nm or less. max For example, the polycyclic compound represented by Chemical Formula 1 may be a light-emitting material having a central emission wavelength in the wavelength region of 430 nm or more and 490 nm or less.

[0076] In one embodiment, Chemical Formula 1 is represented by Chemical Formula 2 below. [ka] ...(chemical formula 2)

[0077] In Chemical Formula 2, R 1 ~R 18 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms, or a substituted or unsubstituted amino group.

[0078] In Chemical Formula 2, Y1, Y2, and Y3 are each independently *-NRa-*, *-O-*, or *-S-*, and Ra is a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms.

[0079] In Chemical Formula 2, the same as that described above in Chemical Formula 1 applies to Y1, Y2, and Y3.

[0080] Chemical formula 2 may be represented by any one of the following chemical formulas 2-1 to 2-7. [ka] [ka] [ka]

[0081] In chemical formulas 2-1 to 2-7, Ra 1 , Ra 2 , and Ra 3 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms.

[0082] In chemical formulas 2-1 to 2-7, R 1 ~R 18 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms, or a substituted or unsubstituted amino group.

[0083] The polycyclic compound according to an embodiment may be any one of the compounds shown in the following first compound group. The organic electroluminescent device 10 according to an embodiment may include at least one of the polycyclic compounds shown in the first compound group in the emission layer EML.

[0084] [First compound group] [ka] [ka] [ka] [ka] [ka] [ka]

[0085] The polycyclic compound according to an embodiment is a thermally activated delayed fluorescent material. As described above, the polycyclic compound according to an embodiment is provided in a state in which aromatic rings are bonded to each other by a linker, and maintains a high lowest triplet excitation energy level and exhibits a narrow half-width during emission. In other words, the organic electroluminescent device according to an embodiment exhibits high efficiency and excellent white reproducibility by including the polycyclic compound according to the embodiment in the emission layer.

[0086] The polycyclic compound represented by Chemical Formula 1 according to an embodiment may be a blue thermally activated delayed fluorescent dopant.

[0087] In the organic electroluminescent device 10 according to an embodiment, the emitting layer EML emits delayed fluorescence. For example, the emitting layer EML may emit thermally activated delayed fluorescence (TADF).

[0088] Meanwhile, although not shown, the organic electroluminescent device 10 according to an embodiment may include a plurality of light-emitting layers. The plurality of light-emitting layers are provided by being sequentially stacked, and for example, the organic electroluminescent device 10 including the plurality of light-emitting layers may emit white light. The organic electroluminescent device including the plurality of light-emitting layers may be an organic electroluminescent device having a tandem structure. When the organic electroluminescent device 10 includes a plurality of light-emitting layers, at least one of the light-emitting layers EML includes the polycyclic compound according to the embodiment described above.

[0089] In one embodiment, the emission layer EML includes a host and a dopant, and includes the polycyclic compound according to the embodiment described above as a dopant. For example, in the organic electroluminescent device 10 according to one embodiment, the emission layer EML includes a delayed fluorescent host and a delayed fluorescent dopant, and the polycyclic compound according to the embodiment described above may be used as a delayed fluorescent dopant. The emission layer EML may include at least one of the polycyclic compounds shown in the first compound group described above as a thermally activated delayed fluorescent dopant.

[0090] In one embodiment, the emitting layer EML is a delayed fluorescent emitting layer, and the emitting layer MEL comprises a known host material and the polycyclic compound according to the above embodiment.For example, in one embodiment, the polycyclic compound can be used as a TADF dopant.

[0091] On the other hand, in one embodiment, the emitting layer EML includes a known host material. For example, the emitting layer EML includes Alq 3 (tris(8-hydroxyquinolino)aluminum), CBP (4,4'-bis(N-carbazolyl)-1,1'-biphenyl), PVK (poly(n-vinylcarbazole), ADN (9,10-di(naphthalen-2-yl)anthracene), TCTA (4,4',4"-tris(carbazol-9-yl)-triphenylamine), TPBi (1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene), TBADN (3-tert-butyl-9 ,10-Di(naphth-2-yl)anthracene), DSA (Distyrylarylene), CDBP (4,4'-Bis(9-carbazolyl)-2,2'-dimethyl-biphenyl), MADN (2-Methyl-9,10-bis(naphthalen-2-yl)anthracene), DPEPO (Bis[2-(diphenylphosphino)phenyl]ether oxide), CP1 (Hexaphenylcyclotriphosphazene), UGH2 (1,4-Bis(triphenylsilyl)benzene), DPSiO 3 (Hexaphenylcyclotrisiloxane), DPSiO 4(octaphenylcyclotetrasiloxane), or PPF (2,8-bis(diphenylphosphoryl)dibenzofuran), mCBP (3,3'-bis(N-carbazolyl)-1,1'-biphenyl), mCP (1,3-bis(N-carbazolyl)benzene), etc. However, without being limited thereto, the emitting layer EML may contain a known delayed fluorescent host material in addition to the presented host materials.

[0092] In the organic electroluminescent device 10 according to the embodiment, the emission layer EML may further include a known dopant material. For example, the light-emitting layer MEL may further include, as a dopant, a styryl derivative (e.g., 1,4-bis[2-(3-N-ethylcarbazolyl)vinyl]benzene (BCzVB), 4-(di-p-tolylamino)-4′-[(di-p-tolylamino)styryl]stilbene (DPAVB), N-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl)naphthalen-2-yl)vinyl)phenyl)-N-phenylbenzenamine (N-BDAVBi), perylene and its derivatives (e.g., 2,5,8,11-tetra-t-butylperylene (TBP)), pyrene and its derivatives (e.g., 1,1-dipyrene, 1,4-dipyrenylbenzene, 1,4-bis(N,N-diphenylamino)pyrene), or the like.

[0093] In the organic electroluminescent device 10 according to the embodiment shown in Figures 1 to 4, the electron transport region ETR is provided on the emission layer EML. The electron transport region ETR includes at least one of a hole blocking layer HBL, an electron transport layer ETL, and an electron injection layer EIL, but is not limited to these.

[0094] The electron transport region ETR has a single layer made of a single material, a single layer made of a plurality of different materials, or a multilayer structure having a plurality of layers made of a plurality of different materials.

[0095] For example, the electron transport region ETR may have a single layer structure of an electron injection layer EIL or an electron transport layer ETL, or may have a single layer structure made of an electron injection material and an electron transport material. The electron transport region ETR may have a single layer structure made of a plurality of different materials, and may have a structure of an electron transport layer ETL / electron injection layer EIL or a hole blocking layer HBL / electron transport layer ETL / electron injection layer EIL stacked in order from the light emitting layer EML, but is not limited thereto. The thickness of the electron transport region ETR may be, for example, about 100 nm to about 150 nm.

[0096] The electron transport region ETR can be formed using various methods such as vacuum deposition, spin coating, casting, LB method, inkjet printing, laser printing, and laser thermal transfer.

[0097] When the electron transport region ETR includes the electron transport layer ETL, the electron transport region ETR includes an anthracene-based compound. However, the electron transport region is not limited thereto, and may include, for example, Alq 3 (Tris(8-hydroxyquinolinato)aluminum), 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, 2,4,6-tris(3'-pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzoimidazolyl-1-ylphenyl)-9,10-dinaphthylanthracene, TPBi(1,3,5-tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl), BCP(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), Bph en (4,7-diphenyl-1,10-phenanthroline), TAZ (3-(4-biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole), NTAZ (4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole), tBu-PBD (2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole), BAlq (bis(2-methyl-8-quinolinolato-N1,O8)-(1,1'-biphenyl-4-olato)aluminum), Bebq 2(beryllium bis(benzoquinoline-10-olate), ADN (9,10-di(naphthalen-2-yl)anthracene), BmPyPhB (1,3-bis[3,5-di(pyridin-3-yl)phenyl]benzene), and mixtures thereof. The electron transport layer ETL may have a thickness of about 10 nm to about 100 nm, for example, about 15 nm to about 50 nm. When the thickness of the electron transport layer HTL satisfies the above-mentioned range, sufficient electron transport properties can be obtained without a substantial increase in driving voltage.

[0098] When the electron transport region ETR includes an electron injection layer EIL, the electron transport region ETR may be formed of a metal halide such as LiF, NaCl, CsF, RbCl, or RbI, a lanthanide metal such as Yb, or Li 2 The electron injection layer EIL may include, but is not limited to, a metal oxide such as O or BaO, or LiQ (lithium quinolate). The electron injection layer EIL may also include a material in which an electron transport material and an insulating organo metal salt are mixed. The organo metal salt is a material having an energy band gap of about 4 eV or more. In detail, for example, the organo metal salt includes metal acetate, metal benzoate, metal acetoacetate, metal acetylacetonate, or metal stearate. The thickness of the electron injection layer EIL is about 0.1 nm to about 10 nm, or about 0.3 nm to about 9 nm. When the thickness of the electron injection layer EIL satisfies the above-mentioned range, sufficient electron injection characteristics can be obtained without a substantial increase in driving voltage.

[0099] The electron transport region ETR may include a hole blocking layer HBL as described above. The hole blocking layer HBL may include at least one of, for example, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) and Bphen (4,7-diphenyl-1,10-phenanthroline), but is not limited thereto.

[0100] The second electrode EL2 is provided on the electron transport region ETR. The second electrode EL2 may be a common electrode or a negative electrode. The second electrode EL2 is a transmissive electrode, a semi-transmissive electrode, or a reflective electrode. If the second electrode EL2 is a transmissive electrode, the second electrode EL2 is made of a transparent metal oxide, such as ITO, IZO, ZnO, ITZO, etc.

[0101] If the second electrode EL2 is a semi-transmissive electrode or a reflective electrode, the second electrode EL2 may contain Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, or a compound or mixture containing these (for example, an alloy of Ag and Mg). The second electrode EL2 may have a multi-layer structure including a reflective film or semi-transmissive film made of the above-mentioned material, and a transparent conductive film made of ITO, IZO, ZnO, ITZO, or the like.

[0102] Although not shown, the second electrode EL2 may be connected to an auxiliary electrode. When the second electrode EL2 is connected to the auxiliary electrode, the resistance of the second electrode EL2 can be reduced.

[0103] A capping layer CPL may be further disposed on the second electrode EL2 of the organic electroluminescent device 10 according to the embodiment. The capping layer CPL may be, for example, α-NPD, NPB, TPD, m-MTDATA, Alq 3 , CuPc, TPD15 (N4,N4,N4',N4'-tetra(biphenyl-4-yl)biphenyl-4,4'-diamine), TCTA (4,4',4"-tris(carbazolesol-9-yl)triphenylamine), N,N'-bis(naphthalene-1-yl), and the like.

[0104] The organic electroluminescent device 10 according to one embodiment of the present invention exhibits excellent luminous efficiency and a narrow half width in the emission wavelength region of blue light by including the polycyclic compound according to the embodiment described above in the emitting layer EML disposed between the first electrode EL1 and the second electrode EL2. In addition, the polycyclic compound according to one embodiment is a thermally activated delayed fluorescence dopant, and the emitting layer EML contains the polycyclic compound and emits thermally activated delayed fluorescence, thereby exhibiting good luminous efficiency characteristics.

[0105] Meanwhile, the polycyclic compound according to the embodiment described above may 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 an embodiment of the present invention may include the polycyclic compound described above 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.

[0106] The polycyclic compound according to the embodiment described above has a structure in which aromatic rings each containing an N atom and a B atom as a ring-forming heteroatom are bonded to each other, and thus exhibits a high lowest triplet excitation energy level and is used as a delayed fluorescent light-emitting material. In addition, an organic electroluminescent device including the polycyclic compound according to the embodiment in an emission layer emits blue light having a narrow half-width and exhibits high efficiency characteristics.

[0107] Hereinafter, a polycyclic compound according to an embodiment of the present invention and an organic electroluminescent device according to an embodiment will be described in detail with reference to examples and comparative examples. The following examples are merely illustrative examples for aiding in understanding the present invention, and the scope of the present invention is not limited thereto. EXAMPLES

[0108] 1. Synthesis of polycyclic compounds First, the synthesis method of the polycyclic compound according to the present embodiment will be specifically described by taking as an example the synthesis methods of compounds 2, 6, and 8. The synthesis method of the polycyclic compound described below is an example, and the synthesis method of the compound according to the embodiment of the present invention is not limited to the following example.

[0109] (1) Synthesis of Compound 2 Compound 2 is synthesized, for example, by the steps of the following Reaction Scheme 1-1 to Reaction Scheme 1-4.

[0110] <Synthesis of intermediate compound 2-A> Intermediate compound 2-A was synthesized according to the steps of the following reaction formula 1-1 to reaction formula 1-3. [Reaction Scheme 1-1] [ka]

[0111] 3-Bromo-4-methylaniline (50.0 g, 268.7 mmol) was placed in a three-neck flask, HCl (200 ml) was added, and the mixture was heated and stirred at 60°C for 1 hour. Then, the temperature was lowered to 0°C, and NaNO 2 (20.4 g, 295.6 mmol) was added dropwise, and the mixture was stirred for 1 hour. Next, KI (49.1 g, 295.6 mmol) dissolved in 20 ml of water was added dropwise, and the mixture was heated and stirred at 60°C for 4 hours. Water and toluene were added to the reaction liquid, and the liquid was separated. The organic layer was concentrated to obtain 2-bromo-4-iodo-1-methylbenzene (34.7 g, yield 43%). The molecular weight of 2-bromo-4-iodo-1-methylbenzene measured by FAB-MS measurement was m / z = 296 (M + +1).

[0112] [Reaction Scheme 1-2] [ka]

[0113] In an argon atmosphere, 2-bromo-4-iodo-1-methylbenzene (30.3 g, 102.1 mmol), 3-bromo-4-methylaniline (9.5 g, 51.1 mmol), and Pd(dppf)Cl were placed in a three-neck flask. 2(0.2 g, 0.5 mmol), NaOtBu (12.3 g, 127.7 mmol) were added, toluene (500 ml) was added, and the mixture was heated and stirred at 130°C for 12 hours. Water and toluene were added to the reaction mixture, and the organic layer was concentrated. The solid obtained by concentration was purified by column chromatography (hexane:toluene = 3:1) to obtain tris(3-bromo-4-methylphenyl)amine (17.1 g, yield 64%). The molecular weight measurement of tris(3-bromo-4-methylphenyl)amine by FAB-MS measurement was m / z = 524 (M + +1).

[0114] [Reaction Scheme 1-3] [ka]

[0115] Under an argon atmosphere, a three-neck flask was charged with tris(3-bromo-4-methylphenyl)amine (10.0 g, 19.1 mmol), di-p-tolylamine (11.7 g, 59.2 mmol), and Pd 2 (bda) 3 (1.0 g, 1.1 mmol), [P( t Bu) 3 ]HBF 4 (1.3 g, 4.6 mmol), NaOtBu (8.3 g, 85.9 mmol), and toluene (500 ml) were added, and the mixture was heated and stirred at 130°C for 4 hours. Water and toluene were added to the reaction mixture, and the organic layer was then concentrated. The solid obtained by concentration was purified by column chromatography (hexane:toluene = 3:1) to obtain intermediate compound 2-A (16.1 g, yield 84%). The molecular weight measurement of intermediate compound 2-A measured by FAB-MS was m / z = 873 (M + +1).

[0116] <Synthesis of compound 2> [Reaction Scheme 1-4] [ka]

[0117] Under an argon atmosphere, intermediate compound 2-A (2.0 g, 2.3 mmol), BPh 3 (1.1g, 4.5mmol), BI 3 (4.5 g, 11 mmol) was added to the reaction mixture, 1,3,5-trichlorobenzene (200 ml) was added, and the mixture was heated and stirred at 180° C. for 6 hours. Water and toluene were added to the reaction mixture, and the organic layer was then concentrated. The solid obtained by concentration was ultrasonically washed with a hexane / toluene mixed solvent and recrystallized from toluene to obtain compound 2 (1.2 g, yield 51%). The molecular weight of compound 2 measured by FAB-MS was m / z=897 (M + +1).

[0118] (2) Synthesis of compound 6 Compound 6 can be synthesized, for example, by the steps of the following Reaction Scheme 2-1 to Reaction Scheme 2-4.

[0119] <Synthesis of intermediate compound 6-A> Intermediate compound 6-A was synthesized according to the steps of the following reaction formula 2-1 to reaction formula 2-3.

[0120] [Reaction Scheme 2-1] [ka]

[0121] In an argon atmosphere, 5-amino-2-methylphenol (14.8 g, 120.0 mmol), 1-iodo-4-methylbenzene (26.2 g, 120 ml), picolinic acid (1.65 g, 12.4 mmol), CuI (1.2 g, 6.1 mmol), and K were added to a three-neck flask. 3 PO 4(51.7 g, 243.6 mmol) was added, DMSO (800 ml) was added, and the mixture was heated and stirred at 130°C for 6 hours. Water and toluene were added to the reaction mixture, and the mixture was separated, and the organic layer was concentrated. The solid obtained by concentration was purified by column chromatography (hexane:toluene = 3:1) to obtain 4-methyl-3-(p-tolyloxy)aniline (20 g, yield 62%). The molecular weight of 4-methyl-3-(p-tolyloxy)aniline measured by FAB-MS measurement was m / z = 213.3 (M + +1).

[0122] [Reaction Scheme 2-2] [ka]

[0123] 4-Methyl-3-(p-tolyloxy)aniline (12.0 g, 56.3 mmol) was placed in a three-neck flask, HCl (100 ml) was added, and the mixture was heated and stirred at 60°C for 1 hour. The temperature was lowered to 0°C, and NaNO 2 (4.2 g, 61.9 mmol) was added dropwise, and the mixture was stirred for 1 hour. Next, KI (10.3 g, 61.9 mmol) dissolved in 10 ml of water was added dropwise, and the mixture was heated and stirred at 60°C for 6 hours. Water and toluene were added to the reaction liquid, and the liquid was separated. The organic layer was concentrated to obtain 4-iodo-1-methyl-2-(p-tolyloxy)benzene (10.7 g, yield 59%). The molecular weight of 4-iodo-1-methyl-2-(p-tolyloxy)benzene measured by FAB-MS measurement was m / z = 325 (M + +1).

[0124] [Reaction Scheme 2-3] [ka]

[0125] In an argon atmosphere, 4-methyl-3-(p-tolyloxy)aniline (2.9 g, 13.6 mmol), 4-iodo-1-methyl-2-(p-tolyloxy)benzene (8.8 g, 27.2 mmol), and Pd 2 (bda) 3 (0.7 g, 0.8 mmol), [P( t Bu) 3 ]HBF 4 (0.95 g, 3.3 mmol), NaOtBu (5.9 g, 27.2 mmol) were added, toluene (300 ml) was added, and the mixture was heated and stirred at 130°C for 6 hours. Water and toluene were added to the reaction mixture, and the organic layer was concentrated. The solid obtained by concentration was purified by column chromatography (hexane:toluene = 3:1) to obtain intermediate compound 6-A (7.4 g, yield 90%). The molecular weight measurement of intermediate compound 6-A measured by FAB-MS was m / z = 606 (M + +1).

[0126] <Synthesis of compound 6> [Reaction Scheme 2-4] [ka]

[0127] Under an argon atmosphere, intermediate compound 6-A (2.0 g, 3.3 mmol), BPh 3 (2.4g, 9.9mmol), B.I. 3 (8.4 g, 21.5 mmol) was added to the reaction mixture, 1,3,5-trichlorobenzene (200 ml) was added, and the mixture was heated and stirred at 180° C. for 6 hours. Water and toluene were added to the reaction mixture, and the mixture was separated, and the organic layer was concentrated. The solid obtained by concentration was ultrasonically washed with a hexane / toluene mixed solvent and then recrystallized with toluene to obtain compound 6 (1.6 g, yield 90%). The molecular weight measurement value of compound 6 measured by FAB-MS measurement was m / z = 630 (M + +1).

[0128] (3) Synthesis of compound 8 Compound 8 is synthesized, for example, by the steps of the following Reaction Scheme 3-1 to Reaction Scheme 3-4.

[0129] <Synthesis of intermediate compound 8-A> Intermediate compound 8-A was synthesized according to the steps of Reaction Scheme 3-1 to Reaction Scheme 3-3 below.

[0130] [Reaction Scheme 3-1] [ka]

[0131] In an argon atmosphere, 5-amino-2-isopropylphenol (18.1 g, 120.0 mmol), 1-iodo-4-isopropylbenzene (29.5 g, 120 ml), picolinic acid (1.65 g, 12.4 mmol), CuI (1.2 g, 6.1 mmol), and K were added to a three-neck flask. 3 PO 4 (51.7 g, 243.6 mmol) was added, DMSO (800 ml) was added, and the mixture was heated and stirred at 130° C. for 6 hours. Water and toluene were added to the reaction mixture, and the mixture was separated, and the organic layer was concentrated. The solid obtained by concentration was purified by column chromatography (hexane:toluene=3:1) to obtain 4-isopropyl-3-(4-isopropylphenoxy)aniline (20 g, yield 62%). The molecular weight of 4-isopropyl-3-(4-isopropylphenoxy)aniline measured by FAB-MS measurement was m / z=269 (M + +1).

[0132] [Reaction Scheme 3-2] [ka]

[0133] 4-Isopropyl-3-(4-isopropylphenoxy)aniline (15 g, 56.3 mmol) was placed in a three-neck flask, HCl (100 ml) was added, and the mixture was heated and stirred at 60°C for 1 hour. The temperature was lowered to 0°C, and NaNO 2(4.2 g, 61.9 mmol) was added dropwise, and the mixture was stirred for 1 hour. Next, KI (10.3 g, 61.9 mmol) dissolved in 10 ml of water was added dropwise, and the mixture was heated and stirred at 60°C for 6 hours. Water and toluene were added to the reaction liquid, and the liquid was separated. The organic layer was concentrated to obtain 4-iodo-1-isopropyl-2-(4-isopropylphenoxy)benzene (9.8 g, yield 46%). The molecular weight of 4-iodo-1-isopropyl-2-(4-isopropylphenoxy)benzene measured by FAB-MS measurement was m / z = 381 (M + +1).

[0134] [Reaction Scheme 3-3] [ka]

[0135] In an argon atmosphere, a three-neck flask was charged with 4-isopropyl-3-(4-isopropylphenoxy)aniline (3.2 g, 12.0 mmol), 4-iodo-1-isopropyl-2-(4-isopropylphenoxy)benzene (9.1 g, 24.0 mmol), and Pd 2 (bda) 3 (0.7 g, 0.8 mmol), [P( t Bu) 3 ]HBF 4 (0.95 g, 3.3 mmol), NaOtBu (5.9 g, 27.2 mmol) were added, toluene (300 ml) was added, and the mixture was heated and stirred at 130°C for 6 hours. Water and toluene were added to the reaction mixture, and the organic layer was concentrated. The solid obtained by concentration was purified by column chromatography (hexane:toluene = 3:1) to obtain intermediate compound 8-A (6.0 g, yield 64%). The molecular weight measurement of intermediate compound 8-A measured by FAB-MS was m / z = 774 (M + +1).

[0136] <Synthesis of compound 8> [Reaction Scheme 3-4] [ka]

[0137] Under an argon atmosphere, intermediate compound 8-A (2.3 g, 3.0 mmol), BPh 3 (2.4g, 9.9mmol), B.I. 3 (8.4 g, 21.5 mmol) was added to the reaction mixture, and 1,3,5-trichlorobenzene (200 ml) was added, followed by heating and stirring at 180° C. for 6 hours. Water and toluene were added to the reaction mixture, followed by liquid separation, and the organic layer was concentrated. The solid obtained by concentration was ultrasonically washed with a hexane / toluene mixed solvent and then recrystallized from toluene to obtain compound 8 (1.3 g, yield 54%). The molecular weight measurement of compound 8 measured by FAB-MS was m / z = 797.4 (M + +1).

[0138] 2. Evaluation of polycyclic compounds and fabrication and evaluation of organic electroluminescence devices The luminescence characteristics of the polycyclic compound according to an embodiment and the organic electroluminescence device according to an embodiment including the polycyclic compound in the luminescent layer were evaluated by the following method. A method for fabricating an organic electroluminescence device for evaluating the device is described below.

[0139] The polycyclic compounds 2, 6, and 8 described above were used as the dopant material of the light-emitting layer to fabricate the organic electroluminescent devices of Examples 1 to 3. Comparative Examples 1 to 3 are organic electroluminescent devices fabricated using the comparative compounds C1, C2, and C3 shown below, respectively, as the dopant material of the light-emitting layer.

[0140] The compounds used in Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1. [Table 1]

[0141] (Evaluation of the luminescence properties of compounds) For the example compounds and the comparative example compounds, 5.0 mM toluene solutions were prepared and the emission characteristics were evaluated using a JASCO V-670 spectrometer. The emission spectra were measured at room temperature and 77 K. Table 2 shows the maximum wavelength λ in the emission spectrum measured at room temperature. max The full width at half maximum (FWHM) and emission spectrum onset values ​​at 77K were also shown. 1 The levels were calculated and shown. [Table 2]

[0142] Referring to the results in Table 2, compounds 2, 6, and 8, which are polycyclic compounds of the examples, show maximum emission wavelengths of 465 nm or less, which indicates that the polycyclic compounds of the examples emit deep blue light. Also, in the emission spectra of compounds 2, 6, and 8, which are polycyclic compounds of the examples, the full width at half maximum (FWHM) appears narrow at 35 nm or less.

[0143] It can be seen that the comparative example compound C1 exhibits a maximum emission wavelength in a similar wavelength region as the example compounds, but has a large half-value width, emitting light with reduced color purity.

[0144] The comparative compound C2 emits light with a narrow half-width and high color purity, but the maximum emission wavelength is longer than that of the compounds of the examples.The comparative compound C3 emits light with a longer wavelength and a wider half-width than the compounds of the examples, which shows that it emits light with reduced color purity.

[0145] In other words, the polycyclic compounds of the examples have a higher triplet energy level (T 1 By maintaining this level, it emits deep blue light with high color purity.

[0146] (Fabrication of Organic Electroluminescent Device) After patterning a 150 nm thick ITO film on a glass substrate, the substrate was washed with ultrapure water and ultrasonically cleaned, then irradiated with UV light for 30 minutes and then treated with ozone. Next, HAT-CN was evaporated to a thickness of 10 nm, α-NPD was evaporated to a thickness of 80 nm, and mCP was evaporated to a thickness of 5 nm to form a hole transport region.

[0147] Next, when forming the light-emitting layer, the polycyclic compound according to one embodiment or the comparative compound and mCBP were co-deposited at a ratio of 1:99 to form a layer having a thickness of 20 nm. That is, in the light-emitting layers formed by co-deposition, compounds 2, 6, and 8 were mixed with mCBP and deposited, respectively, in Examples 1 to 3, and comparative compounds C1, C2, and C3 were mixed with mCBP and deposited, respectively, in Comparative Examples 1 to 3.

[0148] Next, a 30 nm thick layer of TPBi was formed on the light-emitting layer, and a 5 nm thick layer of Liq was formed to form the electron transport region. A 100 nm thick second electrode was then formed from aluminum (Al).

[0149] The hole transport region, the light emitting layer, the electron transport region, and the second electrode described above were formed using a vacuum deposition apparatus.

[0150] (Evaluation of the characteristics of organic electroluminescent devices) Table 3 shows the evaluation results of the organic electroluminescence devices corresponding to Examples 1 to 3 and Comparative Examples 1 to 3. Table 3 shows the maximum emission wavelength λ max and external quantum efficiency EOE max In the results of the characteristic evaluation corresponding to the examples and comparative examples shown in Table 3, the maximum emission wavelength λ max indicates the wavelength at which the emission spectrum has a maximum value, and the external quantum efficiency EOE max、1000nit is 1000cd / m 2 The efficiency at luminance is shown. [Table 3]

[0151] Referring to the results in Table 3, it can be seen that the organic electroluminescent devices of Examples 1 to 3 emit deep blue light with a short wavelength, and exhibit high efficiency characteristics, as compared with the organic electroluminescent devices of Comparative Examples 1 to 3.

[0152] In the case of the example compound, the heteroatom (N, O, S, etc.) adjacent to B (boron) bonds and bridges the adjacent aromatic rings, inducing distortion in the compound and resulting in high T 1 Also, such a high T 1 It is believed that reverse intersystem crossing occurs easily due to the influence of the levels, and in the case of the examples, high external quantum efficiency is exhibited.

[0153] On the other hand, in the case of Comparative Example 1, although it emits light at a short wavelength, it shows a low external quantum efficiency value. This is because the Comparative Example Compound C1 has a low T 1 It is believed that this is because the TADF emission due to reverse intersystem crossing is not expressed due to the presence of the T 1 It is believed that the level is so low that TADF emission is not expressed, and a relatively low external quantum efficiency value is shown. In addition, in the case of Comparative Example 3, the aromatic polycyclic rings of Comparative Example Compound C3 are not bonded to each other by heteroatoms (N, O, S, etc.), so distortion is not induced within the compound, and S 1 Level and T 1 It is believed that all of the levels are lower, resulting in light of a longer wavelength and a lower external quantum efficiency value.

[0154] In one embodiment of the polycyclic compound, a heteroatom (such as N, O, or S) adjacent to B (boron) in an aromatic ring is bonded to adjacent aromatic rings to form a bridge, thereby inducing distortion of the compound and exhibiting a high T 1 By maintaining the level, the organic electroluminescent device emits short wavelength blue light and exhibits high efficiency characteristics. In addition, by including the polycyclic compound according to an embodiment in the light emitting layer, the organic electroluminescent device according to an embodiment has a narrow half width in the emission wavelength range, exhibits excellent color characteristics, and exhibits high luminous efficiency characteristics.

[0155] Although the present invention has been described above with reference to an embodiment, it should be understood that a person skilled in the art or having ordinary knowledge in the relevant technical field can modify and change the present invention in various ways without departing from the spirit and technical scope of the present invention as described in the claims below.

[0156] Therefore, the technical scope of the present invention should be determined not by the contents described in the detailed description of the specification, but by the claims. [Explanation of symbols]

[0157] 10: Organic electroluminescent element EL1: First electrode EL2: second electrode HTR: hole transport region EML: Light-emitting layer ETR: Electron transport region

Claims

1. A first electrode; A second electrode disposed on the first electrode; a light-emitting layer disposed between the first electrode and the second electrode, the light-emitting layer including a polycyclic compound represented by the following Chemical Formula 1: The first electrode and the second electrode each independently include one selected from the group consisting of silver (Ag), magnesium (Mg), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), LiF / Ca, LiF / Al, molybdenum (Mo), titanium (Ti), indium (In), tin (Sn), and zinc (Zn), a compound including a plurality of elements selected from among these elements, a mixture including a plurality of elements selected from among these elements, or an oxide of one or more elements selected from among these elements. 【Chemistry 1】 ...(chemical formula 1) (In the above Chemical Formula 1, A1, A2, and A3 each independently represent a substituted or unsubstituted hydrocarbon ring having from 5 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycle having from 2 to 30 ring carbon atoms; A1 does not form a condensed ring structure with X1, A2 does not form a condensed ring structure with X2, A3 does not form a fused ring structure with X3, X1, X2, and X3 each independently represent a substituted or unsubstituted hydrocarbon ring having from 5 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycle having from 2 to 30 ring carbon atoms; Y1, Y2, and Y3 each independently represent *-NRa-*, *-O-*, or *-S-*; Ra is a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms.

2. A1, A2, and A3 each independently represent an unsubstituted benzene ring or a benzene ring substituted with at least one substituent; 2. The organic electroluminescent device according to claim 1, wherein the at least one substituent is a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms, or a substituted or unsubstituted amino group.

3. 2. The organic electroluminescent device according to claim 1, wherein X1, X2, and X3 each independently represent a benzene ring substituted with at least one of a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms, and a substituted or unsubstituted amino group.

4. The organic electroluminescent device according to claim 1 , wherein the formula 1 is represented by the following formula 2: 【Chemistry 2】 ...(chemical formula 2) (In the above Chemical Formula 2, R １ ~R １８ are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms, or a substituted or unsubstituted amino group.

5. The organic electroluminescent device of claim 1 , wherein Y1, Y2, and Y3 are all the same.

6. 2. The organic electroluminescent device according to claim 1, wherein at least one of Y1, Y2, and Y3 is *-NRa-*, and the rest are *-O-* or *-S-*.

7. The organic electroluminescent device according to claim 1 , wherein the light-emitting layer emits delayed fluorescence.

8. The light-emitting layer comprises a host and a dopant, The organic electroluminescent device according to claim 1 , wherein the dopant comprises the polycyclic compound.

9. The organic electroluminescent device according to claim 1 , wherein the light emitting layer emits light having a central wavelength of 430 nm or more and 470 nm or less.

10. The organic electroluminescent device according to claim 1 , wherein the light-emitting layer comprises at least one of the polycyclic compounds of the following first compound group: [First compound group] 【Chemistry 3】 【Chemistry 4】 【Chemistry 5】 【Chemistry 6】 【Chemistry 7】 【Chemistry 8】

11. A polycyclic compound represented by the following chemical formula 1. 【Chemistry 9】 ...(chemical formula 1) (In the above Chemical Formula 1, A1, A2, and A3 each independently represent a substituted or unsubstituted hydrocarbon ring having from 5 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycle having from 2 to 30 ring carbon atoms; X1, X2, and X3 each independently represent a substituted or unsubstituted hydrocarbon ring having from 5 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycle having from 2 to 30 ring carbon atoms; A1 does not form a condensed ring structure with X1, A2 does not form a condensed ring structure with X2, A3 does not form a fused ring structure with X3, Y1, Y2, and Y3 each independently represent *-NRa-*, *-O-*, or *-S-*; Ra is a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms.

12. A1, A2, and A3 each independently represent an unsubstituted benzene ring or a benzene ring substituted with at least one substituent; The polycyclic compound according to claim 11, wherein the at least one substituent is a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms, or a substituted or unsubstituted amino group.

13. The polycyclic compound according to claim 11, wherein X1, X2, and X3 are each independently a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms, and a substituted or unsubstituted amino group, and a benzene ring substituted or unsubstituted with at least one of them.

14. The polycyclic compound according to claim 11 , wherein the formula 1 is represented by the following formula 2: 【Chemistry 10】 ...(chemical formula 2) (In the above Chemical Formula 2, R １ ~R １８ are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having from 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having from 2 to 30 ring carbon atoms, or a substituted or unsubstituted amino group.

15. The polycyclic compound of claim 11, wherein Y1, Y2, and Y3 are all the same.

16. The polycyclic compound according to claim 11, wherein at least one of Y1, Y2, and Y3 is *-NRa-*, and the rest are *-O-* or *-S-*.

17. The polycyclic compound according to claim 11, wherein the polycyclic compound represented by Chemical Formula 1 is a blue dopant that emits blue light having a central wavelength of 470 nm or less.

18. The lowest triplet excitation energy level (T １ The polycyclic compound according to claim 11 , wherein the electron transport level is greater than 2.6 eV.

19. The polycyclic compound according to claim 11, wherein the polycyclic compound represented by Chemical Formula 1 is a thermally activated delayed fluorescent material.

20. The polycyclic compound according to claim 11 , wherein the compound represented by Chemical Formula 1 is any one of the compounds represented by the following first compound group: [First compound group] 【Chemistry 11】 【Chemistry 12】 【Chemistry 13】 【Chemistry 14】 【Chemistry 15】 【Chemistry 16】

Images