Organic electroluminescent element and polycyclic compound for organic electroluminescent element

Abstract

To provide an organic electroluminescent device with high efficiency.SOLUTION: An organic electroluminescent device includes a first electrode, a hole transport region on the first electrode, an emission layer on the hole transport region, an electron transport region on the emission layer, and a second electrode on the electron transport region, wherein the emission layer includes a polycyclic compound represented by Formula 1. In Formula 1, X1 is C, Si or Ge, Ar is an aryl group or a heteroaryl group, and AC is an electron acceptor.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an organic electroluminescent device and a polycyclic compound used therein.

Background Art

[0002] As a video display device, the development of an organic electroluminescent device (Organic Electroluminescence Device) has been actively carried out. Different from a liquid crystal display device and the like, an organic electroluminescent device is a so-called self-luminous display device that realizes display by causing a light-emitting material, which is an organic compound contained in a light-emitting layer, to emit light by recombining holes and electrons injected from a first electrode and a second electrode in the light-emitting layer.

[0003] As an organic electroluminescent device, for example, an organic device including a first electrode, a hole transport layer disposed on the first electrode, a light-emitting layer disposed on the hole transport layer, an electron transport layer disposed on the light-emitting layer, and a second electrode disposed on the electron transport layer is known. Holes are injected from the first electrode, and the injected holes move through the hole transport layer and are injected into the light-emitting layer. On the other hand, electrons are injected from the second electrode, and the injected electrons move through the electron transport layer and are injected into the light-emitting layer. When the holes and electrons injected into the light-emitting layer recombine, excitons are generated in the light-emitting layer. The organic electroluminescent device emits light by using the light generated when the excitons fall back to the ground state again. Further, the organic electroluminescent device is not limited to the configuration described above, and various modifications are possible.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] One of the objects of the present invention is to provide an organic electroluminescent element and a polycyclic compound used therefor.

Means for Solving the Problems

[0006] According to one embodiment of the present invention, there is provided an organic electroluminescent element including a first electrode, a hole transport region provided on the first electrode, a light-emitting layer provided on the hole transport region, an electron transport region provided on the light-emitting layer, and a second electrode provided on the electron transport region, wherein the light-emitting layer contains a polycyclic compound represented by the following Chemical Formula 1.

[0007]

Chem.

[0008] In Chemical Formula 1, X1 is C, Si, or Ge; Ar is a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms; R1 to R4 are each independently a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms; a to d are each independently an integer of 0 or more and 4 or less; and AC is a structure represented by any one of the following Chemical Formulas 2 to 10.

[0009]

Chem.

[0010] In Chemical Formula 2, Z1 to Z 13 are each independently CH or N, two or three of Z1 to Z3 are N, at least one of Z4 to Z 13 is N, and e is an integer of 0 or more and 2 or less.

[0011] In Chemical Formula 3, X2 is O, S or CR8R9, R5 to R7 are each independently a deuterium atom, or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, and may be bonded to adjacent groups to form a hydrocarbon ring or a heterocyclic ring, R8 and R9 are each independently a hydrogen atom, a deuterium atom, or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, f is an integer of 0 or more and 3 or less, g is an integer of 0 or more and 4 or less, and h is an integer of 0 or more and 5 or less.

[0012] In Chemical Formula 4, i is an integer of 0 to 2, Y1 is N or CR 10 is, Y2 is N or CR 11 is, Y3 is N or CR 12 is, Y4 is N or CR 13 is, Y5 is N or CR 14 is, at least one of Y1 to Y5 is N, and R 10 ~R 14 are each independently a hydrogen atom, a deuterium atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, or a trifluoromethyl group. When X1 in Chemical Formula 1 is C, at least one of R 10 ~R 14 is not a hydrogen atom, and when at least one of Y2 and Y4 is N, Y3 is CR 12 is, and R12 is not a cyano group.

[0013] In Chemical Formula 7, A1 to A 13 are each independently N or CR 15 and at least one of A1 to A8 is N, at least one of A9 to A 13 is N, and one of A1 to A 13 is a site bonded to the N of Chemical Formula 1, and R 15 is a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.

[0014] In Chemical Formula 8, B1 to B 10 are each independently N or CR 16 and one of B1 to B 10 is a site bonded to the N of Chemical Formula 1, X3 is a direct linkage, O, S, CR 17 R 18 or SiR 19 R 20 and j is 0 or 1. When j is 1, B5 and B6 are C, and R 16 to R 20 are each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.

[0015] In Chemical Formula 9, E1 to E 10 are each independently N or CR 21 and one of E1 to E 10 is a site bonded to the N of Chemical Formula 1, X4 is a single bond, O, S, CR 22 R 23 or SiR 24 R 25 and k is 0 or 1. When k is 1, E5 and E6 are C, and R21 ~R 25 is independently a hydrogen atom, a deuterium atom , a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.

[0016] Chemical formula 3 may be represented by the following chemical formula 3-1 or chemical formula 3-2.

[0017]

Chem.

[0018] In chemical formula 3-1 and chemical formula 3-2, X2, R5, R6, f and g are the same as defined in chemical formula 3, and Y1 and Y2 are independently O, S or CR 26 R 27 and R 26 and R 27 are independently a hydrogen atom, a deuterium atom, or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms.

[0019] Chemical formula 4 may be represented by any one of the following chemical formulas.

[0020]

Chem.

[0021] Chemical formula 7 may be represented by any one of the following chemical formulas.

[0022]

Chem.

[0023] Chemical formula 8 may be represented by any one of the following chemical formulas.

[0024]

Chem.

[0025] Chemical formula 9 may be represented by any one of the following chemical formulas.

[0026]

Chem.

[0027] In Chemical formula 1, Ar may be a substituted or unsubstituted phenyl group.

[0028] The light-emitting layer contains a host and a dopant, and the dopant may contain a polycyclic compound represented by Chemical formula 1.

[0029] The polycyclic compound represented by Chemical formula 1 may be a dopant for thermally activated delayed fluorescence.

[0030] The polycyclic compound represented by Chemical formula 1 may be a blue dopant having a wavelength region of less than 470 nm.

[0031] The hole transport region may include a hole injection layer disposed on the first electrode, a hole transport layer disposed on the hole injection layer, and an electron blocking layer disposed on the hole transport layer.

[0032] The electron transport region may include a hole blocking layer disposed on the light-emitting layer, an electron transport layer disposed on the hole blocking layer, and an electron injection layer disposed on the electron transport layer.

[0033] According to one embodiment of the present invention, a polycyclic compound represented by the above Chemical formula 1 is provided.

Advantages of the Invention

[0034] The organic electroluminescent device according to one embodiment of the present invention is excellent in efficiency.

[0035] The polycyclic compound according to one embodiment of the present invention can be applied to an organic electroluminescent device and can contribute to higher efficiency.

Brief Description of the Drawings

[0036]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0037] The above objects, other objects, features, and advantages of the present invention will be easily understood from the accompanying drawings and the following preferred embodiments. However, the present invention is not limited to the embodiments described herein and can be realized in other forms. Rather, the embodiments introduced here are provided so that the disclosed content is thorough and complete and that the idea of the present invention is sufficiently conveyed to those of ordinary skill in the art.

[0038] In describing each drawing, similar reference numerals are used for similar components. In the accompanying drawings, the dimensions of the structures are shown enlarged for clarity of the present invention. Terms such as first and second are used to describe various components, but the above components should not be limited by the above terms. The above terms are used only for the purpose of distinguishing one component from another. For example, within the scope not departing from the scope of the claims of the present invention, the first component may be named the second component, and similarly, the second component may also be named the first component. Singular expressions include plural expressions unless the context clearly has a different meaning.

[0039] In this specification, terms such as "comprising" or "having" are used to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and it should be understood that they do not preclude the presence or possibility of addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. Also, when a part such as a layer, film, region, or plate is "on" another part, it includes not only the case where it is "directly on" the other part but also the case where there are other parts in between. Conversely, when a part such as a layer, film, region, or plate is "under" another part, it includes not only the case where it is "directly under" the other part but also the case where there are other parts in between.

[0040] First, an organic electroluminescent device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

[0041] FIG. 1 is a cross-sectional view schematically showing an organic electroluminescent device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing an organic electroluminescent device according to an embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing an organic electroluminescent device according to an embodiment of the present invention.

[0042] Referring to FIGS. 1 to 3, an organic electroluminescent device 10 according to an embodiment of the present invention includes a first electrode EL1, a hole transport region HTR, a light-emitting layer EML, an electron transport region ETR, and a second electrode EL2.

[0043] The first electrode EL1 has conductivity. The first electrode EL1 may be a pixel electrode or an anode. The first electrode EL1 may be a transmissive electrode, a transflective electrode, or a reflective electrode. When the first electrode EL1 is a transmissive electrode, the first electrode EL1 may contain a transparent metal oxide, such as ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), ITZO (indium tin zinc oxide), etc. When the first electrode EL1 is a transflective electrode or a reflective electrode, the first electrode EL1 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 thereof (e.g., an alloy of Ag and Mg). Or it may be a multi-layer structure including a reflective film or a transflective film formed of the above substances and a transparent conductive film formed of ITO, IZO, ZnO, ITZO, etc. For example, the first electrode EL1 may have a three-layer structure of ITO / Ag / ITO, but is not limited thereto.

[0044] 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.

[0045] 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, and an electron blocking layer EBL. The thickness of the hole transport region HTR may be, for example, about 100 nm to about 150 nm.

[0046] The hole transport region HTR may be a single layer composed of a single substance, a single layer composed of a plurality of different substances, or a multi-layer structure having a plurality of layers composed of a plurality of different substances.

[0047] 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 may have a single-layer structure composed of a hole injection material and a hole transport material. Further, the hole transport region HTR may have a single-layer structure composed of a plurality of different substances, or may have a structure of a hole injection layer HIL / hole transport layer HTL, a hole injection layer HIL / hole transport layer HTL / hole buffer layer, a hole injection layer HIL / hole buffer layer, a hole transport layer HTL / hole buffer layer, or a hole injection layer HIL / hole transport layer HTL / electron blocking layer EBL laminated in order from the first electrode EL1, but is not limited thereto.

[0048] The hole transport region HTR may be formed using various methods such as a vacuum evaporation method, a spin coating method, a casting method, an LB method (Langmuir-Blodgett), an inkjet printing method, a laser printing method, a laser induced thermal imaging method (LITI), etc.

[0049] The hole injection layer HIL includes, for example, phthalocyanine compounds 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-methylphenylphenylamino)triphenylamine), TDATA (4,4’4’’-Tris(N,N-diphenylamino)triphenylamine), 2-TNATA (4,4’,4’’-tris{N,-(2-naphthyl)-N-phenylamino}-triphenylamine), PEDOT / PSS (Poly(3,4-ethylenedioxythiophene) / Poly(4-styrenesulfonate)), PANI / DBSA (Polyaniline / It may contain dodecylbenzenesulfonic acid, PANI / CSA (Polyaniline / Camphor sulfonic acid), PANI / PSS ((Polyaniline) / Poly(4-styrenesulfonate)), NPD (N,N’-di(naphthalene-l-yl)-N,N’-diplienyl-benzidine), polyether ketone containing 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), etc.

[0050] The hole transport layer HTL may contain, for example, carbazole derivatives such as N-phenylcarbazole and polyvinylcarbazole, fluorene derivatives, triphenylamine derivatives such as TPD (N,N’-bis(3-methylphenyl)-N,N’-diphenyl-[1,1-biphenyl]-4,4’-diamine) and TCTA (4,4’,4’’-tris(N-carbazolyl)triphenylamine), NPB (N,N’-di(naphthalene-l-yl)-N,N’-diplienyl-benzidine), TAPC (4,4’-Cyclohexylidene bis[N,N-bis(4-methylphenyl)benzenamine]), HMTPD (4,4’-Bis[N,N’-(3-tolyl)amino]-3,3’-dimethylbiphenyl), etc.

[0051] The thickness of the hole transport region HTR may be from about 10 nm to about 1000 nm, for example, it may be from about 10 nm to about 100 nm. When the hole transport region HTR includes both the hole injection layer HIL and the hole transport layer HTL, the thickness of the hole injection layer HIL is from about 10 nm to about 1000 nm, for example, from about 10 nm to about 100 nm, and the thickness of the hole transport layer HTL may be from about 3 nm to about 100 nm. When the thicknesses of the hole transport region HTR, the hole injection layer HIL, and the hole transport layer HTL satisfy the above ranges, excellent hole transport characteristics can be obtained without substantial increase in driving voltage.

[0052] In addition to the substances described above, the hole transport region HTR may further contain a charge generating substance for improving conductivity. The charge generating substance may be uniformly or non-uniformly dispersed in the hole transport region HTR. The charge generating substance may be, for example, a p-dopant. The p-dopant may be one of a quinone derivative, a metal oxide, and a cyano group-containing compound, but is not limited thereto. For example, examples of the p-dopant include quinone derivatives such as TCNQ (Tetracyanoquinodimethane) and F4-TCNQ (2,3,5,6-tetrafluoro-tetracyanoquinodimethane), metal oxides such as tungsten oxide and molybdenum oxide, etc., but are not limited thereto.

[0053] As described above, in addition to the hole injection layer HIL and the hole transport layer HTL, the hole transport region HTR may further include at least one of a hole buffer layer and an electron blocking layer. The hole buffer layer can compensate for the resonance distance according to the wavelength of the light emitted from the light emitting layer EML to increase the light emission efficiency. As the substance contained in the hole buffer layer, the substances that can be contained in the hole transport region HTR can be used. The electron blocking layer is a layer that plays a role of preventing electron injection from the electron transport region ETR to the hole transport region HTR.

[0054] The light-emitting layer EML is provided on the hole transport region HTR. The light-emitting layer EML may have 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 may be a single layer composed of a single substance, a single layer composed of a plurality of different substances, or a multilayer structure having a plurality of layers composed of a plurality of different substances.

[0055] The light-emitting layer EML contains a polycyclic compound according to an embodiment of the present invention. Hereinafter, the polycyclic compound according to an embodiment of the present invention will be described in detail.

[0056] JPEG0007714013000017.jpg12154

[0057] "Substituted or unsubstituted" means substituted or unsubstituted with one or more substituents selected from the group consisting of a deuterium atom, a halogen atom, a cyano group, a nitro group, an amino group, a silyl group, a boron group, a phosphine oxide group, a phosphine sulfide group, an alkyl group, an alkenyl group, an aryl group, and a heterocyclic group. Further, each of the above-exemplified 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. The heterocyclic group includes an aliphatic heterocycle and an aromatic heterocycle (heteroaryl group).

[0058] For example, "substituted or unsubstituted" may mean substituted or unsubstituted with one or more substituents selected from the group consisting of a deuterium atom, a halogen atom, a cyano group, an alkyl group, an aryl group, and a heterocyclic group.

[0059] In this specification, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

[0060] In this specification, the alkyl group may be linear, branched, or cyclic. The number of carbon atoms of the alkyl group is 1 or more and 30 or less, 1 or more and 20 or less, 1 or more and 10 or less, or 1 or more and 5 or less. Examples of the alkyl group include, but are not limited to, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, i-butyl group, 2-ethylbutyl group, 3,3-dimethylbutyl group, n-pentyl group, i-pentyl group, neopentyl group, t-pentyl group, cyclopentyl group, 1-methylpentyl group, 3-methylpentyl group, 2-ethylpentyl group, 4-methyl-2-pentyl group, n-hexyl group, 1-methylhexyl group, 2-ethylhexyl group, 2-butylhexyl group, cyclohexyl group, 4-methylcyclohexyl group, 4-t-butylcyclohexyl group, n-heptyl group, 1-methylheptyl group, 2,2-dimethylheptyl group, 2-ethylheptyl group, 2-butylheptyl group, n-octyl group, t-octyl group, 2-ethyloctyl group, 2-butyloctyl group, 2-hexyloctyl group, 3,7-dimethyloctyl group, cyclooctyl group, n-nonyl group, n-decyl group, adamantyl group, 2-ethyldecyl group, 2-butyldecyl group, 2-hexyldecyl group, 2-octyldecyl group, n-undecyl group, n-dodecyl group, 2-ethyldodecyl group, 2-butyldodecyl group, 2-hexyldodecyl group, 2-octyldodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, 2-ethylhexadecyl group, 2-butylhexadecyl group, 2-hexylhexadecyl group, 2-octylhexadecyl group, 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, and n-triacontyl group, etc.

[0061] In this specification, the alkenyl group may be linear or branched. The number of carbon atoms is not particularly limited, but is 2 or more and 30 or less, 2 or more and 20 or less, or 2 or more and 10 or less. Examples of the alkenyl group include, but are not limited to, vinyl group, 1-butenyl group, 1-pentenyl group, 1,3-butadienylaryl group, styrenyl group, styrylvinyl group, etc.

[0062] In this specification, the aryl group means any functional group or substituent derived from an aromatic hydrocarbon ring. The aryl group may be a monocyclic aryl group or a polycyclic aryl group. The number of ring-forming carbon atoms of the aryl group may be 6 or more and 60 or less, 6 or more and 30 or less, 6 or more and 20 or less, or 6 or more and 15 or less. Examples of the aryl group include, but are not limited to, phenyl group, naphthyl group, fluorenyl group, anthracenyl group, phenanthryl group, biphenylyl group, terphenylyl group, quarterphenylyl group, kinkphenyl group, sexiphenyl group, biphenylene group, triphenylene group, pyrenyl group, benzofluoranthenyl group, chrysenyl group, etc.

[0063] In this specification, the fluorenyl group may be substituted, and two substituents may be bonded to each other to form a spiro structure. Examples of the case where the fluorenyl group is substituted are as follows. However, it is not limited thereto.

[0064]

Chemical formula

[0065] In this specification, the heterocyclic group may contain one or more of B, O, N, P, Si, and S as heteroatoms. When the heterocyclic group contains two or more heteroatoms, the two or more heteroatoms may be the same as or different from each other. The heterocyclic group may be a monocyclic heterocyclic group, a polycyclic heterocyclic group, or a heteroaryl group. The number of ring-forming carbon atoms of the heterocyclic group may be 2 or more and 30 or less, 2 or more and 20 or less, or 2 or more and 10 or less. Examples of the heterocyclic group include, but are not limited to, thiophenyl group, furanyl group, pyrrolyl group, imidazolyl group, thiazolyl group, oxazolyl group, oxadiazolyl group, triazolyl group, pyridinyl group, bipyridinyl group, pyrimidinyl group, triazinyl group, triazolyl group, acridinyl group, pyridazinyl group, pyrazinyl group, quinolinyl group, quinazolinyl group, quinoxalinyl group, phenoxazinyl group, pteridinyl group, pyridopyrimidinyl group, pyridopyrazinyl group, pyrazinoprazinyl group, isoquinolinyl group, indolyl group, carbazolyl group, N-arylcarbazolyl group, N-heteroarylcarbazolyl group, N-alkylcarbazolyl group, benzoxazolyl group, benzimidazolyl group, benzothiazolyl group, benzocarbazolyl group, benzothiophenyl group, dibenzothiophenyl group, thienothiophenyl group, benzofuranyl group, phenanthrolinyl group, thiazolyl group, isoxazolyl group, oxadiazolyl group, thiadiazolyl group, phenothiazinyl group, dibenzosilolyl group, and dibenzofuranyl group, etc.

[0066] In this specification, the silyl group includes an alkylsilyl group and an arylsilyl group. Examples of the silyl group include, but are not limited to, trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, vinyldimethylsilyl group, propyldimethylsilyl group, triphenylsilyl group, diphenylsilyl group, phenylsilyl group, etc.

[0067] In this specification, the boron group includes an alkylboron group and an arylboron group. Examples of the boron group include, but are not limited to, a trimethylboron group, a triethylboron group, a t-butyldimethylboron group, a triphenylboron group, a diphenylboron group, a phenylboron group, and the like.

[0068] In this specification, the number of carbon atoms of the amino group is not particularly limited, but may be 1 or more and 30 or less. The amino group may include 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, a triphenylamino group, and the like.

[0069] In this specification, the phosphine oxide group may be substituted with at least one of, for example, an alkyl group and an aryl group. Examples of the phosphine oxide group include, but are not limited to, a phenylphosphine oxide group, a diphenylphosphine oxide group, and the like.

[0070] In this specification, the phosphine sulfide group may be substituted with at least one of an alkyl group and an aryl group.

[0071] The polycyclic compound according to one embodiment of the present invention is represented by the following Chemical Formula 1.

[0072]

Chemical Formula

[0073] In Chemical Formula 1, X1 is C, Si, or Ge. Ar is a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. R1 to R4 are each independently a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. a to d are each independently an integer of 0 or more and 4 or less. AC is represented by any one of the following Chemical Formulas 2 to 10.

[0074] [Chemical Formula] JPEG0007714013000024.jpg3779 JPEG0007714013000025.jpg1878 JPEG0007714013000026.jpg4172 JPEG0007714013000027.jpg4268 JPEG0007714013000028.jpg3974 JPEG0007714013000029.jpg2874 JPEG0007714013000030.jpg2880

[0075] In Chemical Formula 2, Z1 to Z 13 are each independently CH or N, two or three of Z1 to Z3 are N, at least one of Z4 to Z 13 is N, and e is an integer of 0 or more and 2 or less.

[0076] In Chemical Formula 3, X2 is O, S, or CR8R9. R5 to R7 are each independently a deuterium atom, or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, and may combine with adjacent groups to form a hydrocarbon ring or a heterocyclic ring. R8 and R9 are each independently a hydrogen atom, a deuterium atom, or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, and may combine with adjacent groups to form a hydrocarbon ring or a heterocyclic ring. f is an integer of 0 or more and 3 or less, g is an integer of 0 or more and 4 or less, and h is an integer of 0 or more and 5 or less.

[0077] In Chemical Formula 4, i is an integer of 0 to 2, Y1 is N or CR 10 wherein Y2 is N or CR 11 wherein Y3 is N or CR 12 wherein Y4 is N or CR 13 wherein Y5 is N or CR 14 wherein at least one of Y1 to Y5 is N, and R 10 ~R 14 are each independently a hydrogen atom, a deuterium atom, a cyano group, or a trifluoromethyl group. When X1 in Chemical Formula 1 is C, at least one of R 10 ~R 14 is not a hydrogen atom. When at least one of Y2 and Y4 is N, Y3 is CR 12 and R 12 is not a cyano group.

[0078] In Chemical Formula 7, A1 to A 13 are each independently N or CR 15 wherein at least one of A1 to A8 is N, at least one of A9 to A 13 is N, and one of A1 to A 13 is a bonding site with N in Chemical Formula 1. R 15 is a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.

[0079] In Chemical Formula 8, B1 to B 10 are each independently N or CR 16 and one of B1 to B 10 is a site bonded to N of Chemical Formula 1. X3 is a single bond, O, S, CR 17 R 18 or SiR 19 R 20 and j is 0 or 1. When j is 1, B5 and B6 are C. R 16 to R 20 are each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.

[0080] In Chemical Formula 9, E1 to E 10 are each independently N or CR 21 and one of E1 to E 10 is a site bonded to N of Chemical Formula 1. X3 is a single bond, O, S, CR 22 R 23 or SiR 24 R 25 and k is 0 or 1. When k is 1, E5 and E6 are C. R 21 to R 25 are each independently a hydrogen atom, a deuterium atom , a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.

[0081] In Chemical Formula 1, when a is 2 or more, a plurality of R1s are the same as or different from each other; when b is 2 or more, a plurality of R2s are the same as or different from each other; when c is 2 or more, a plurality of R3s are the same as or different from each other; and when d is 2 or more, a plurality of R4s are the same as or different from each other.

[0082] In Chemical Formula 1, when at least one of a to d is 0, a hydrogen atom is bonded to the carbon atom to which R1 to R4 can be bonded.

[0083] For example, each of a to d may be 0. However, it is not limited thereto, and for the purpose of adjusting the energy level of the polycyclic compound or the like, at least one of a to d may be 1 or more, and a substituent other than a hydrogen atom may be introduced.

[0084] In Chemical Formula 1, Ar may be a substituted or unsubstituted aryl group having 6 to 20 carbon atoms. For example, Ar may be a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenylyl group, a substituted or unsubstituted anthracenyl group, a substituted or unsubstituted phenanthrenyl group, or a substituted or unsubstituted terphenylyl group. For example, Ar may be a substituted or unsubstituted phenyl group. For example, Ar may be an unsubstituted phenyl group.

[0085] AC in Chemical Formula 1 is an electron-withdrawing group, and the structure excluding AC in Chemical Formula 1 is an electron-donating group. That is, the polycyclic compound according to one embodiment of the present invention contains an electron-withdrawing group and an electron-donating group in one molecule.

[0086] In Chemical Formula 2, at least one of Z5 to Z7 and Z 10 ~Z 12 may be N.

[0087] In Chemical Formula 3, when f is 2 or more, the plurality of R5s are the same as or different from each other, when g is 2 or more, the plurality of R6s are the same as or different from each other, and when h is 2 or more, the plurality of R7s are the same as or different from each other.

[0088] In Chemical Formula 3, when at least one of f to h is 0, a hydrogen atom is bonded to the carbon atom to which R5 to R7 can be bonded.

[0089] For example, h is 1 or more, and R7 may be an alkyl group having 1 to 5 carbon atoms which may be substituted or unsubstituted. Chemical formula 3 may be represented by, for example, the following chemical formula 3-1.

[0090] [Chemical formula]

[0091] In chemical formula 3-1, X2, R5, R6, f and g are the same as defined in chemical formula 3. Chemical formula 3-1 may be more specifically represented by the following chemical formula 3-1-1 or chemical formula 3-1-2.

[0092] [Chemical formula] JPEG0007714013000033.jpg5193

[0093] In chemical formula 3-1-1 and chemical formula 3-1-2, X2 is the same as defined in chemical formula 3.

[0094] In chemical formula 3, X2 may be O or S. In chemical formula 3, X2 is CR8R9, and R8 and R9 may each independently be a substituted or unsubstituted methyl group.

[0095] As described above, in chemical formula 3, R5 to R7 can also be bonded to adjacent groups to form a hydrocarbon ring or a heterocyclic ring. For example, chemical formula 3 may be represented by the following chemical formula 3-2.

[0096] [Chemical formula]

[0097] In chemical formula 3-2, X2 is the same as defined in chemical formula 3, and Y1 and Y2 are each independently O, S or CR 26 R 27 where R 26 and R27 is independently a hydrogen atom, a deuterium atom, or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms. For example, R 26 and R 27 may each independently be a substituted or unsubstituted methyl group.

[0098] In Chemical Formula 3-2, at least one of Y1 and Y2 may be CR 26 R 27 as well.

[0099] More specifically, Chemical Formula 3-2 may be represented by any one of the following Chemical Formulas 3-2-1 to 3-2-5.

[0100]

Chemical Formula

[0101] Chemical Formula 4 may be represented by, for example, any one of the following chemical formulas. However, it is not limited thereto.

[0102]

Chemical Formula

[0103] Chemical Formula 7 may be represented by, for example, any one of the following chemical formulas. However, it is not limited thereto.

[0104]

Chemical Formula

[0105] Chemical formula 8 may be represented by any one of the following chemical formulas, for example. However, it is not limited thereto.

[0106]

Chem.

[0107] Chemical formula 9 may be represented by any one of the following chemical formulas, for example. However, it is not limited thereto.

[0108]

Chem.

[0109] The polycyclic compound represented by Chemical formula 1 may be any one selected from the compounds represented by the following Compound Group 1. However, it is not limited thereto.

[0110] [Compound Group 1]

Chem.

[0111] The polycyclic compound according to an embodiment of the present invention may have a difference between the singlet energy level and the triplet energy level of 0.2 eV or less, and as a result, it can be used as a thermally activated delayed fluorescence material. The polycyclic compound according to an embodiment of the present invention is applied to a material for an organic electroluminescent device and can contribute to an improvement in efficiency.

[0112] Also, the organic electroluminescent device will be described with reference to FIGS. 1 to 3.

[0113] The light-emitting layer EML contains one or more polycyclic compounds represented by Chemical Formula 1. The light-emitting layer EML may further contain known substances in addition to the polycyclic compound represented by Chemical Formula 1.

[0114] The light-emitting layer EML may contain a host and a dopant, and the dopant may contain a polycyclic compound represented by Chemical Formula 1. The polycyclic compound according to an embodiment of the present invention is a dopant for thermally activated delayed fluorescence and may be contained in the light-emitting layer EML. The polycyclic compound according to an embodiment of the present invention is a blue light dopant having a wavelength region of less than 470 nm, for example, a deep blue light dopant having a wavelength region of 440 nm to about 470 nm, or about 450 nm to about 470 nm.

[0115] As the host material, general materials known in the art can be adopted without limitation. For example, it may contain at least one of DPEPO (Bis[2-(diphenylphosphino)phenyl]ether oxide), CBP (4,4’-Bis(carbazol-9-yl)biphenyl), mCP (1,3-Bis(carbazol-9-yl)benzene), PPF (2,8-Bis(diphenylphosphoryl)dibenzo[b,d]furan), TcTa (4,4’,4’’-Tris(carbazol-9-yl)-triphenylamine), and TPBi (1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene).However, it is not limited by this. For example, Alq3 (tris(8-hydroxyquinolino)aluminum), CBP (4,4’-bis(N-carbazolyl)-1,1’-biphenyl), PVK (poly(n-vinylcabazole)), ADN (9,10-di(naphthalene-2-yl)anthracene), TCTA (4,4’,4’’-Tris(carbazol-9-yl)-triphenylamine), TPBi (1,3,5-tris(N-phenylbenzimidazole-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 (Hexaphenyl cyclotriphosphazene), UGH2 (1,4-Bis(triphenylsilyl)benzene), DPSiO3 (Hexaphenylcyclotrisiloxane), DPSiO4 (Octaphenylcyclotetra siloxane), PPF (2,8-Bis(diphenylphosphoryl)dibenzofuran), etc. can be used as host materials.

[0116] For example, the light-emitting layer EML may further contain at least one of TPD (N,N,N’,N’-tetraphenyl-pyrene-1,6-diamine), BCzVBi (4,4’-Bis(2-(9-ethyl-9H-carbazol-3-yl)vinyl)-1,1’-biphenyl; 4,4’-Bis(9-ethyl-3-carbazovinylene)-1,1’-biphenyl), ACRSA (10-phenyl-10H,10’H-spiro[acridine-9,9’-anthracene]-10’-one), 4CzPN (3,4,5,6-Tetra-9H-carbazol-9-yl-1,2-benzenedicarbonitrile), 4CzIPN (2,4,5,6-Tetra-9H-carbazol-9-yl-isophthalonitrile), DMAC-DPS (Bis[4-9,9-dimethyl-9,10-dihydroacridine)phenyl]solfone), and PSZ-TRZ (2-phenoxazine-4,6-diphenyl-1,3,5-triazine). Further, the light-emitting layer EML may further contain, as known dopant materials, styryl derivatives (e.g., 1,4-bis[2-(3-N-ethylcarbazoryl)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), etc.).

[0117] The light-emitting layer EML may be a blue light-emitting layer that emits blue light. The light-emitting layer EML may be a light-emitting layer that emits light in a wavelength region of 480 nm or less, or 470 nm or less. The light-emitting layer EML may be a fluorescent light-emitting layer that emits fluorescent light. The light-emitting layer EML may be a delayed fluorescent light-emitting layer that emits delayed fluorescent light.

[0118] The electron transport region ETR is provided on the light-emitting layer EML. The electron transport region ETR may include, but is not limited to, at least one of a hole blocking layer HBL, an electron transport layer ETL, and an electron injection layer EIL.

[0119] The electron transport region ETR may have a single-layer structure composed of a single substance, a single-layer structure composed of a plurality of different substances, or a multilayer structure composed of a plurality of layers composed of a plurality of different substances.

[0120] 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 a single-layer structure composed of an electron injection substance and an electron transport substance. Further, the electron transport region ETR may have a single-layer structure composed of a plurality of different substances, or a structure of an electron transport layer ETL / electron injection layer EIL, a hole blocking layer HBL / electron transport layer ETL / electron injection layer EIL laminated 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.

[0121] The electron transport region ETR may be formed using various methods such as a vacuum evaporation method, a spin coating method, a casting method, an LB method, an inkjet printing method, a laser printing method, a laser thermal transfer method, and the like.

[0122] When the electron transport region ETR includes the electron transport layer ETL, the electron transport region ETR may contain an anthracene-based compound. However, it is not limited thereto, and the electron transport region may include, for example, Alq3 (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), Bphen (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), Bebq2 (berylliumbis(benzoquinolin-10-olate), ADN (9,10-di(naphthalene-2-yl)anthracene), and mixtures thereof. The thickness of the electron transport layer ETL may be about 10 nm to about 100 nm, for example, about 15 nm to about 50 nm. When the thickness of the electron transport layer ETL satisfies the above range, excellent electron transport characteristics can be obtained without a substantial increase in the driving voltage.

[0123] When the electron transport region ETR includes an electron injection layer EIL, the electron transport region ETR can use, but is not limited to, LiF, LiQ (Lithium quinolate), Li2O, BaO, NaCl, CsF, lanthanoid metals such as Yb, or metal halides such as RbCl, RbI, etc. Alternatively, the electron injection layer EIL may be composed of a substance in which an electron transporting substance and an insulating organo metal salt are mixed. The organo metal salt may be a substance having an energy band gap of about 4 eV or more. Specifically, for example, the organo metal salt may include metal acetate, metal benzoate, metal acetoacetate, metal acetylacetonate, or metal stearate. The thickness of the electron injection layer EIL may be 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 range, excellent electron injection characteristics can be obtained without a substantial increase in the driving voltage.

[0124] As described above, the electron transport region ETR may include a hole blocking layer HBL. The hole blocking layer HBL may include, for example, but is not limited to, at least one of BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) and Bphen (4,7-diphenyl-1,10-phenanthroline).

[0125] 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 may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode. When the second electrode EL2 is a transmissive electrode, the second electrode EL2 may be made of a transparent metal oxide, such as ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), ITZO (indium tin zinc oxide), etc.

[0126] When 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). Or it may be a structure of a plurality of layers including a reflective film or a semi-transmissive film formed of the above substances and a transparent conductive film formed of ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), ITZO (indium tin zinc oxide), etc.

[0127] 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.

[0128] In the organic electroluminescent element 10, when voltages are applied to the first electrode EL1 and the second electrode EL2 respectively, the holes injected from the first electrode EL1 move to the light-emitting layer EML through the hole transport region HTR, and the electrons injected from the second electrode EL2 move to the light-emitting layer EML through the electron transport region ETR. The electrons and holes recombine in the light-emitting layer EML to generate excitons, and the excitons emit light while falling from the excited state to the ground state.

[0129] When the organic electroluminescent element 10 is a front emission type, the first electrode EL1 is a reflective electrode, and the second electrode EL2 may be a transmissive electrode or a semi-transmissive electrode. When the organic electroluminescent element 10 is a back emission type, the first electrode EL1 may be a transmissive electrode or a semi-transmissive electrode, and the second electrode EL2 may be a reflective electrode.

[0130] By using the above-described polycyclic compound as a material for the light-emitting layer EML in the organic electroluminescent element 10 according to an embodiment of the present invention, the efficiency is improved.

Example

[0131] Hereinafter, the present invention will be described more specifically through specific examples and comparative examples. The following examples are merely illustrative for helping the understanding of the present invention, and the scope of the present invention is not limited thereto.

[0132] (Synthesis Example) The polycyclic compound according to an embodiment of the present invention can be synthesized, for example, as follows. However, the synthesis method of the polycyclic compound according to an embodiment of the present invention is not limited thereto.

[0133] 1. Synthesis of Compound 8 Compound 8 according to an embodiment of the present invention can be synthesized, for example, as follows.

[0134] (Synthesis of Intermediate 1A)

Chemical formula

[0135] Under an argon (Ar) atmosphere, 2.0 g of compound A was added to a 200 mL three-necked flask, 30 mL of dehydrated diethyl ether was added, and 10 mL of 1.6 M n-BuLi was added dropwise at room temperature. After that, the mixture was stirred at room temperature for 2 hours. Then, compound B dissolved in 20 mL of dehydrated diethyl ether was added dropwise, and then the mixture was stirred for about 12 hours. After the reaction was completed, water was added, the organic layer was separated, and the solvent was distilled off. The obtained crude product was purified by silica gel chromatography (using toluene as the solvent), and 2.20 g (yield 62%) of white solid intermediate 1A was obtained.

[0136] The molecular weight of intermediate 1A measured by FAB-MS measurement was 440.

[0137] (Synthesis of intermediate 2A)

Chemical formula

[0138] Under an argon (Ar) atmosphere, 2.0 g of compound 1A was added to a 100 mL three-necked flask, 20 mL of toluene was added, 0.73 g of methanesulfonic acid and 1.0 g of polyphosphoric acid were added thereto, and the mixture was heated under reflux with stirring for 4 hours. After the reaction was completed, water was added, the organic layer was separated, and the solvent was distilled off. The obtained crude product was purified by silica gel chromatography (using toluene as the solvent), and 1.9 g (yield 95%) of white solid intermediate 2A was obtained.

[0139] The molecular weight of intermediate 2A measured by FAB-MS measurement was 422.

[0140] (Synthesis of compound 8)

Chemical formula

[0141] Under an argon (Ar) atmosphere, 1.0 g of compound C, 0.95 g of intermediate 2A, 0.43 g of sodium tert-butoxide, and tris(dibenzyl 0.04 g of bis(acetone)dipalladium(0), 0.05 g of tri-tert-butylphosphonium tetrafluoroborate, and 20 mL of toluene were added, and the mixture was heated under reflux with stirring for 8 hours. After completion of the reaction, water was added, and the organic layer was separated, and the solvent was distilled off. The obtained crude product was purified by silica gel chromatography (using a mixed solvent of toluene and hexane), and 1.7 g (yield 94%) of white solid compound 8 was obtained.

[0142] The molecular weight of compound 8 measured by FAB-MS measurement was 802.

[0143] 2. Synthesis of Compound 40 Compound 40 according to one embodiment of the present invention can be synthesized, for example, as follows.

Chemical formula

[0144] Compound 40 was obtained in a yield of 81% in the same manner as the synthesis of compound 8, except that compound E was used instead of compound C in the synthesis of compound 8. The molecular weight of compound 40 measured by FAB-MS measurement was 661.

[0145] 3. Synthesis of Compound 69 Compound 69 according to one embodiment of the present invention can be synthesized, for example, as follows.

Chemical formula

[0146] Compound 69 was obtained in a yield of 89% in the same manner as the synthesis of compound 8, except that intermediate 3A was used instead of intermediate 2A in the synthesis of compound 8. The molecular weight of compound 69 measured by FAB-MS measurement was 818.

[0147] 4. Synthesis of Compound 127 Compound 127 according to one embodiment of the present invention can be synthesized, for example, as follows.

Chemical formula

[0148] Compound 127 was obtained in 86% yield in the same manner as the synthesis of Compound 8, except that Compound F was used instead of Compound C in the synthesis of Compound 8. The molecular weight of Compound 127 measured by FAB-MS measurement was 602.

[0149] 5. Synthesis of Compound 131 Compound 131 according to an embodiment of the present invention can be synthesized, for example, as follows.

Chemical formula

[0150] Compound 131 was obtained in 91% yield in the same manner as the synthesis of Compound 8, except that Compound G was used instead of Compound C in the synthesis of Compound 8. The molecular weight of Compound 131 measured by FAB-MS measurement was 638.

[0151] The above synthesis examples are illustrative, and the reaction conditions may be changed as necessary. Further, the compounds according to an embodiment of the present invention may be synthesized to have various substituents using methods and materials known in the art. By introducing various substituents into the core structure represented by Chemical formula 1, it is possible to have properties suitable for use in organic electroluminescent elements.

[0152] (Device Fabrication Example) The above-mentioned Compounds 8, 40, 69, 127, and 131 were used as dopant materials for the light-emitting layer, and the organic electroluminescent elements of Examples 1 to 5 were fabricated.

[0153] [Example Compounds]

Chemical formula

[0154] The following compounds C-1 to C-10 were used as the dopant materials for the light-emitting layer, and organic electroluminescent elements of Comparative Examples 1 to 10 were fabricated.

[0155] [Compound of Comparative Example] [Chemical formula] JPEG0007714013000082.jpg3941 JPEG0007714013000083.jpg4754 JPEG0007714013000084.jpg4759 JPEG0007714013000085.jpg4655 JPEG0007714013000086.jpg3237 JPEG0007714013000087.jpg4768 JPEG0007714013000088.jpg3863 JPEG0007714013000089.jpg3953 JPEG0007714013000090.jpg3146

[0156] The S1 level and T1 level of the compound of the example and the compound of the comparative example were calculated by the ab initio molecular orbital method. Specifically, using Gaussian09 manufactured by Gaussian, the calculation was performed using the B3LYP functional and the 6-31G(d) basis function. The results are shown in Table 1 below. ΔE ST means the difference between the singlet energy level and the triplet energy level.

[0157]

Table 1

[0158] Referring to the results in Table 1 above, Examples Compounds 8, 40, 69, 127 and 131, and Comparative Examples Compounds C-2, C-4 to C-9 exhibit low ΔE ST values, and are considered to exhibit thermally activated delayed fluorescence. On the other hand, Comparative Examples Compounds C-1, C-3, C-9 and C-10 exhibit high ΔE ST values, and are considered not to exhibit thermally activated delayed fluorescence. The organic electroluminescent devices of Examples 1 to 5 and Comparative Examples 1 to 10 were formed with a first electrode of 150 nm of ITO, a hole injection layer of 10 nm thickness of HAT-CN, a hole transport layer of 80 nm thickness of NPB, an electron blocking layer of 5 nm thickness of mCP, a light-emitting layer of 20 nm thickness doped with 20% of the above Example compound or the above Comparative Example compound in DPEPO, a hole blocking layer of 10 nm thickness of DPEPO, an electron transport layer of 30 nm thickness of TPBi, an electron injection layer of 0.5 nm thickness of LiF, and a second electrode of 100 nm thickness of Al. All layers were formed by vacuum evaporation method.

[0159] The maximum emission wavelengths (λ max ) and external quantum efficiencies (EQE) of the organic electroluminescent devices according to Examples 1 to 5 and Comparative Examples 1 to 10 were measured and shown in Table 2 below. The EQE in Table 2 is the value at 10 mA / cm 2 .

[0160]

Table 2

[0161] Referring to the results in Table 2 above, Example Compounds 8, 40, 69, 127, and 131 are all dark blue dopants with emission wavelengths of less than 470 nm and have suitable emission wavelengths, and high efficiency due to thermally activated delayed fluorescence was achieved. Comparative Examples 1, 6, 9, and 10 have considerably low luminous efficiency and shorter emission wavelengths compared to Examples 1 to 5. Comparative Examples 4, 5, and 8 have relatively high efficiency but longer wavelengths compared to Examples 1 to 5, and dark blue emission could not be achieved. Comparative Example 7 has a wavelength close to dark blue, but its efficiency is lower than that of Examples 1 to 5. Comparative Example 2 does not have a dark blue band and also did not result in high efficiency. Comparative Example 2 may not exhibit thermally activated delayed fluorescence despite the small calculated value of E ST . Comparative Example 3 has low efficiency, and also has a longer wavelength and cannot achieve dark blue compared to Examples 1 to 5.

[0162] The polycyclic compound according to one embodiment of the present invention can be used as a thermally activated delayed fluorescence dopant for dark blue emission.

[0163] The organic electroluminescent device containing the polycyclic compound according to one embodiment of the present invention can achieve dark blue and high efficiency.

[0164] As described above, the embodiments of the present invention have been explained. Those having ordinary knowledge in the technical field to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing its technical idea and essential features. Therefore, the embodiments described above should be understood as illustrative in all aspects and not restrictive.

Explanation of Symbols

[0165] 10 Organic electroluminescent device EL1 First electrode HTR Hole transport region HIL Hole injection layer HTL Hole transport layer EML Emission layer ETR Electron transport region ETL Electron transport layer EIL Electron Injection Layer EL2 Second Electrode

Claims

1. A polycyclic compound represented by the following Chemical Formula 1. 【Chemical 1】 (In the Chemical Formula 1, X １ is C, Si, or Ge, and Ar is a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, R １ to R ４ each independently represents a deuterium atom, a substituted or unsubstituted carbon atom having 1 to 10 carbon atoms is the following alkyl group, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, a to d are each independently an integer of 0 or more and 4 or less, AC is represented by the following Chemical Formula 3, 【Chemical 2】 in the Chemical Formula 3, X ２ is O, S or CR ８ R ９ is, R ５ ~R ７ each independently represents a deuterium atom, or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, and may or may not combine with adjacent groups to form a hydrocarbon ring or a heterocyclic ring, R ８ 、 R ９ are each independently a hydrogen atom, a deuterium atom, or a substituted or unsubstituted is an alkyl group having 1 to 5 carbon atoms, and may or may not combine with an adjacent group to form a hydrocarbon ring or a heterocyclic ring, f is an integer of 0 or more and 3 or less, g is an integer of 0 or more and 4 or less, h is an integer of 0 or more and 5 or less.)

2. The polycyclic compound according to Claim 1, wherein the Chemical Formula 3 is represented by the following Chemical Formula 3-1 or 3-2. (In the Chemical Formula 3-1, [Chemical Formula 3] 【Chem.】 X2 is X2 in the Chemical Formula 3, R5 and R6 are R5 and R6 in the Chemical Formula 3, f is f in the Chemical Formula 3, g is g in the Chemical Formula 3, in the Chemical Formula 3-2, X2 is X2 in the Chemical Formula 3,

3. Y １ and Y ２ each independently is O, S or CR ２６ R ２７ wherein R ２６ and R ２７ are each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms.) The polycyclic compound according to Claim 1, wherein the polycyclic compound represented by the Chemical Formula 1 is any one selected from the compounds represented by the following Compound Group 1. [Compound Group 1]

4. A first electrode, 【Chemical Formula 4】 【Chem.】 【Chem.】 【Chem.】 【Chem.】 【Chem.】 【Chem.】 【Chem.】 【Chem.】 【Chem.】 [Chemical] a hole transport region provided on the first electrode, a light-emitting layer provided on the hole transport region and containing any one of the polycyclic compounds according to Claims 1 to 3, an electron transport region provided on the light-emitting layer, a second electrode provided on the electron transport region, and wherein the first electrode and the second electrode each independently are selected from the group consisting of 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 containing a plurality selected from these, a mixture containing a plurality selected from these, or one or more oxides selected from these, characterizing an organic electroluminescent device.

5. The light-emitting layer contains a host and a dopant,

5. The light-emitting layer contains a host and a dopant, ​ ​ The organic electroluminescent device according to claim 4, wherein the dopant contains the polycyclic compound. Light emitting device. **Claim 6** The organic electroluminescent device according to claim 5, wherein the polycyclic compound is a blue dopant having a wavelength region of less than 470 nm. Light emitting device.

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