Organic electroluminescent element

Abstract

To provide an organic electroluminescent element with preferable life property and excellent luminous efficiency.SOLUTION: An organic electroluminescent element includes a first electrode and a second electrode, which face each other, and a light-emitting layer disposed between the first electrode and the second electrode. The light-emitting layer includes a host with a first emission start wavelength, a first dopant with a second emission start wavelength, and a second dopant with a third emission start wavelength different from the first dopant. The third emission start wavelength has a larger value than the first emission start wavelength and the second emission start wavelength.SELECTED DRAWING: Figure 6A

Description

Technical Field

[0001] The present invention relates to an organic electroluminescent device, and more particularly to an organic electroluminescent device including a plurality of light-emitting layer materials in a light-emitting layer.

Background Art

[0002] Recently, as a video display device, the development of an organic electroluminescence display has been actively carried out. Different from a liquid crystal display device and the like, the organic electroluminescence display is a so-called self-luminous display device that realizes display by causing holes and electrons injected from a first electrode and a second electrode to recombine in a light-emitting layer, thereby causing a light-emitting material containing an organic compound in the light-emitting layer to emit light.

[0003] When applying an organic electroluminescent device to a display device, reduction of the driving voltage, improvement of the light emission efficiency, and extension of the life of the organic electroluminescent device are required, and the development of materials for an organic electroluminescent device that can stably achieve these is continuously required.

[0004] In particular, recently, technologies related to phosphorescent light emission using the energy of a triplet state to realize a highly efficient organic electroluminescent device and delayed fluorescence emission using a phenomenon (Triplet-triplet annihilation, TTA) in which singlet excitons are generated by the collision of triplet excitons have been developed, and the development of thermally activated delayed fluorescence (TADF) materials using the delayed fluorescence phenomenon has been advanced.

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide an organic electroluminescent device exhibiting good life characteristics and excellent light emission efficiency.

Means for Solving the Problems

[0006] An organic electroluminescent device according to an embodiment of the present invention includes a first electrode, a second electrode facing the first electrode, and a light-emitting layer disposed between the first electrode and the second electrode. The light-emitting layer includes a host having a first emission onset wavelength, a first dopant having a second emission onset wavelength, and a second dopant having a third emission onset wavelength different from the first dopant. The third emission onset wavelength is greater than the first emission onset wavelength and the second emission onset wavelength.

[0007] The normalized light intensity at the intersection of the normalized light absorption spectrum and the normalized emission spectrum of the second dopant may be 0.5 or more.

[0008] The interval between the peak of the normalized light absorption spectrum of the second dopant and the peak of the normalized emission spectrum may be 50 nm or less.

[0009] The lowest triplet excitation energy level of the second dopant may be lower than the lowest triplet excitation energy levels of the host and the first dopant, respectively.

[0010] The host may include a first host and a second host different from the first host.

[0011] The first host may be represented by the following chemical formula H-1.

Chemical formula

[0012] The second host may be represented by the following chemical formula H-2.

Chemical formula

[0013] The first dopant may contain an organometallic complex containing Ir, Ru, Rh, Pt, Pd, Cu, or Os as a central metal atom.

[0014] The first dopant may be represented by the following chemical formula D-1.

Chemical formula

[0015] The second dopant may be represented by the following chemical formula D-2a.

Chemical formula

[0016] The second dopant may be represented by the following chemical formula D-2b.

Chemical formula

Chemical formula

Chemical formula

[0017] The weight ratio of the first host and the second host may be 7:3 to 3:7.

[0018] Based on the total weight of the first host, the second host, the first dopant, and the second dopant, the content of the first dopant may be 10 wt% or more and 15 wt% or less, and the content of the second dopant may be 1 wt% or more and 5 wt% or less.

[0019] An organic electroluminescent device according to an embodiment of the present invention includes a first electrode, a second electrode disposed on the first electrode, and a light-emitting layer disposed between the first electrode and the second electrode. The light-emitting layer includes a first host, a second host different from the first host, a first dopant having a second emission start wavelength, and a second dopant different from the first dopant and having a third emission start wavelength. The third emission start wavelength is greater than the second emission start wavelength, and the normalized light intensity at the intersection of the normalized light absorption spectrum and the normalized emission spectrum of the second dopant is 0.5 or more.

[0020] An organic electroluminescent device according to an embodiment of the present invention includes a first electrode, a second electrode disposed on the first electrode, and a light-emitting layer disposed between the first electrode and the second electrode. The light-emitting layer includes a first host including a hole-transporting partial structure, a second host different from the first host and including an electron-transporting partial structure, a first dopant having a second light emission start wavelength and including an organometallic complex having Ir, Ru, Rh, Pt, Pd, Cu, or Os as a central metal atom, and a second dopant having a third light emission start wavelength and being a delayed fluorescence phosphor. The third light emission start wavelength is greater than the second light emission start wavelength.

Advantages of the Invention

[0021] The organic electroluminescent device according to one embodiment exhibits improved device characteristics of long life and high efficiency.

[0022] The organic electroluminescent device according to one embodiment exhibits high efficiency and long life characteristics by including both two host materials and two dopant materials.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6A

Figure 6B

Figure 6C

Figure 6D

Figure 6E

Figure 6F

Figure 7A

Figure 7B

DETAILED DESCRIPTION OF THE INVENTION

[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. However, this is not intended to limit the present invention to a specific disclosed form, and it should be understood to include all modifications, equivalents, or alternatives included in the spirit and technical scope of the present invention.

[0025] In this specification, when a component (or region, layer, part, etc.) is referred to as being "on", "connected to", or "coupled to" another component, it means that it can be directly disposed, connected, or coupled on the other component, or a third component can be disposed between them.

[0026] Like reference numerals refer to like elements. In the drawings, the thickness, ratios, and dimensions of the elements are exaggerated for an effective illustration of the technical content.

[0027] “And / or” includes all combinations of one or more of the associated components defined by the related components.

[0028] Terms such as first, second, etc. are used to describe various components, but the components are not limited to these terms. The terms are used only for the purpose of distinguishing one structural element from other components. For example, unless departing from the scope of the present invention, the first component may be referred to as the second component, and similarly the second component may be referred to as the first component. Singular expressions include plural expressions unless the context clearly dictates otherwise.

[0029] Also, terms such as “below,” “beneath,” “above,” “on top” are used to explain the correlation of the configurations shown in the drawings. These terms are relative concepts and are explained 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 technical field to which this invention belongs. Also, 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 related art and should not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0031] Terms such as “comprising” or “having” mean that there are the features, numbers, steps, operations, components, parts, or combinations thereof described above in the specification, and it should be understood that the presence or addition possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof is not precluded in advance.

[0032] As used herein, "substituted or unsubstituted" means 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 boryl 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 unsubstituted. Further, each of the exemplified substituents described above 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] As used herein, "combining with adjacent groups to form a ring" means combining with adjacent groups to form a substituted or unsubstituted hydrocarbon ring or a substituted or unsubstituted heterocyclic ring. The hydrocarbon ring includes an aliphatic hydrocarbon ring and an aromatic hydrocarbon ring. The heterocyclic group includes an aliphatic heterocyclic group and an aromatic heterocyclic group. The ring formed by combining adjacent groups with each other is a monocyclic or polycyclic ring. Further, the ring formed by combining with each other may be combined with another ring to form a spiro structure.

[0034] As used herein, "adjacent group" means a substituent substituted on an atom directly bonded to the atom substituted with the said substituent, another substituent substituted on the atom substituted with the said substituent, or the substituent that is the most sterically adjacent to the said substituent. For example, the two methyl groups in 1,2-dimethylbenzene are interpreted as "adjacent groups" to each other, and the two ethyl groups in 1,1-diethylcyclopentene are interpreted as "adjacent groups" to each other.

[0035] Examples of the halogen atom herein include a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

[0036] In this specification, the alkyl group is linear, branched, or cyclic. The number of carbon atoms in the alkyl group is 1 or more and 50 or less, 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 6 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-methylpeptyl 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-octyldecyl 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 group, and n-triacontyl group, etc.

[0037] As used herein, an alkenyl group means a hydrocarbon group containing one or more carbon-carbon double bonds in the middle or at the end of an alkyl group having 2 or more carbon atoms. The alkenyl group is 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, a vinyl group, a 1-butenyl group, a 1-pentenyl group, a 1,3-butadienylaryl group, a styrenyl group, a styrylvinyl group, and the like.

[0038] As used herein, an alkynyl group means a hydrocarbon group containing one or more carbon-carbon triple bonds in the middle or at the end of an alkyl group having 2 or more carbon atoms. The alkynyl group is 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. Specific examples of the alkynyl group include, but are not limited to, an ethynyl group, a propynyl group, and the like.

[0039] As used herein, a 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-forming carbon atoms of the hydrocarbon ring group is 5 or more and 60 or less, 5 or more and 30 or less, or 5 or more and 20 or less.

[0040] As used herein, an 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-forming carbon atoms of the aryl group is 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, a phenyl group, a naphthyl group, a fluorenyl group, an anthracenyl group, a phenanthryl group, a biphenylyl group, a terphenylyl group, a quarterphenyl group, a kinkphenyl group, a sexiphenyl group, a triphenylenyl group, a pyrenyl group, a benzofluoranthenyl group, a chrysenyl group, and the like.

[0041] As used herein, the heterocyclic group means any functional group or substituent derived from a ring containing one or more of B, O, N, P, Si, and S as heteroatoms. The heterocyclic group includes an aliphatic heterocyclic group and an aromatic heterocyclic group. The aromatic heterocyclic group is a heteroaryl group. The aliphatic heterocyclic group and the aromatic heterocyclic group are monocyclic or polycyclic.

[0042] As used herein, the heterocyclic group contains one or more of B, O, N, P, Si, and S as heteroatoms. If 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 or a polycyclic heterocyclic group, and is a concept including a heteroaryl group. The number of ring-forming carbon atoms of the heterocyclic group is 2 or more and 30 or less, 2 or more and 20 or less, or 2 or more and 10 or less.

[0043] As used herein, the aliphatic heterocyclic group contains one or more of B, O, N, P, Si, and S as heteroatoms. The number of ring-forming carbon atoms of the aliphatic heterocyclic group 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 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, a 1,4-dioxanyl group, and the like.

[0044] In this specification, a heteroaryl group contains one or more of B, O, N, P, Si, and S as heteroatoms. If a heteroaryl group contains two or more heteroatoms, the two or more heteroatoms may be the same as or different from each other. The heteroaryl group may be a monocyclic heteroaryl group or a polycyclic heteroaryl group. The number of ring-forming carbon atoms of the heteroaryl group 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 heteroaryl group include, but are not limited to, thiophenyl group, furanyl group, pyrrolyl group, imidazolyl group, triazolyl group, pyridinyl group, bipyridinyl group, pyrimidinyl group, triazinyl group, triazolyl group, acridinyl group, pyridazinyl group, quinolinyl group, quinazolinyl group, quinoxalinyl group, phenoxazinyl group, phthalazinyl 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, oxazolyl group, oxadiazolyl group, thiadiazolyl group, phenothiazinyl group, dibenzosilyl group, and dibenzofuranyl group.

[0045] In this specification, the description regarding the aryl group described above applies to the arylene group, except that the arylene group is a divalent group. The description regarding the heteroaryl group described above applies to the heteroarylene group, except that the heteroarylene group is a divalent group.

[0046] 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, and phenylsilyl group.

[0047] In this specification, the boryl group includes an alkylboryl group and an arylboryl group. Examples of the boryl group include, but are not limited to, a trimethylboryl group, a triethylboryl group, a t-butyldimethylboryl group, a triphenylboryl group, a diphenylboryl group, a phenylboryl group, and the like.

[0048] In this specification, the number of carbon atoms of the amino group is not particularly limited, but is 1 or more and 30 or less. The amino group includes an alkylamino group, an arylamino group, or a heteroarylamino 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.

[0049] In this specification, the oxy group includes an alkoxyoxy group and an aryloxy group. The alkoxy group may be linear, branched, or cyclic. The number of carbon atoms of the alkoxy group is not particularly limited, but may be, for example, 1 or more and 20 or less, or 1 or more and 10 or less. Examples of the oxy group include, but are not limited to, an ethoxy group, an n-propoxy group, an isopropoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, a nonyloxy group, a decyloxy group, a benzyloxy group, and the like.

[0050] In this specification, for the alkyl group in an alkylthio group, an alkylsulfinyl group, an alkylaryl group, an alkylamino group, an alkylboryl group, and an alkylsilyl group, refer to the exemplification of the alkyl group described above.

[0051] In this specification, for the aryl group in an aryloxy group, an arylthio group, an arylsulfinyl group, an arylamino group, an arylboryl group, and an arylsilyl group, refer to the exemplification of the alkyl group described above.

[0052] In this specification, a direct linkage means a single bond.

[0053] JPEG0007691797000017.jpg14130

[0054] Hereinafter, with reference to the drawings, an organic electroluminescent device according to an embodiment of the present invention will be described.

[0055] FIGS. 1 to 5 are cross-sectional views schematically showing an organic electroluminescent device according to an embodiment of the present invention. Referring to FIGS. 1 to 5, in an organic electroluminescent device 10 according to an embodiment, a first electrode EL1 and a second electrode EL2 are arranged to face each other, and a light-emitting layer EML is arranged between the first electrode EL1 and the second electrode EL2.

[0056] Further, the organic electroluminescent device 10 according to an embodiment further includes a plurality of functional layers in addition to the light-emitting layer EML between the first electrode EL1 and the second electrode EL2. 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, a light-emitting layer EML, an electron transport region ETR, and a second electrode EL2 that are sequentially stacked. Further, the organic electroluminescent device 10 of an embodiment may further include a capping layer CPL arranged on the second electrode EL2.

[0057] The organic light-emitting device 10 according to an embodiment includes a compound according to an embodiment of the present invention described later in the light-emitting layer EML arranged between the first electrode EL1 and the second electrode EL2. However, the embodiments of the present invention are not limited thereto, and the organic light-emitting device 10 may include a compound according to an embodiment of the present invention described later in the hole transport region HTR or the electron transport region ETR, which are a plurality of functional layers arranged between the first electrode EL1 and the second electrode EL2, other than the light-emitting layer EML, or may include a compound according to an embodiment of the present invention described later in the capping layer CPL arranged on the second electrode EL2.

[0058] Figure 2 shows a cross-sectional view of the organic electroluminescent device 10 in which the hole transport region HTR includes a hole injection layer HIL and a hole transport layer HTL, and the electron transport region ETR includes an electron injection layer EIL and an electron transport layer ETL. Further, Figure 3 shows a cross-sectional view of the organic electroluminescent device 10 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. Figure 4 shows a cross-sectional view of the organic electroluminescent device 10 including a buffer layer BFL disposed between the light emitting layer EML and the electron transport region ETR. Figure 5 shows a cross-sectional view of the organic electroluminescent device 10 including a capping layer CPL disposed on the second electrode EL2.

[0059] The first electrode EL1 has conductivity. The first electrode EL1 is made of a metal alloy or a conductive compound. The first electrode EL1 is an anode. Alternatively, the first electrode EL1 is 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). Further, the first electrode EL1 may have a multi-layer structure including a reflective film or a semi-transmissive film made of the aforementioned substances, and a transparent conductive film made 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. The thickness of the first electrode EL1 is about 100 nm to about 1000 nm, for example, about 100 nm to about 300 nm.

[0060] The hole transport region HTR is provided on the first electrode EL1. The hole transport region HTR includes 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.

[0061] The hole transport region HTR has a single-layer structure composed of a single substance, a single-layer structure composed of a plurality of different substances, or a multilayer structure having a plurality of layers composed of a plurality of different substances.

[0062] 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 substance and a hole transport substance. Further, the hole transport region HTR may have a single-layer structure composed of a plurality of different substances, or a structure of a hole injection layer HIL / hole transport layer HTL, a hole injection layer HIL / hole transport layer HTL / hole buffer layer (not shown), a hole injection layer HIL / hole buffer layer (not shown), a hole transport layer HTL / hole buffer layer, or a hole injection layer HIL / hole transport layer HTL / electron blocking layer EBL laminated in order from the first electrode EL1, but the embodiments are not limited thereto.

[0063] The hole transport region HTR is formed by 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, and a laser thermal transfer method (Laser Induced Thermal Imaging, LITI).

[0064] The hole injection layer HTL includes, for example, phthalocyanine compounds such as copper phthalocyanine, DNTPD (N,N'-diphenyl-N,N'-bis-[4-phenyl-m-tolylamino)-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-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 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), and the like.

[0065] The hole transport layer HTL may include, for example, N-phenylcarbazole, carbazole derivatives such as polyvinylcarbazole, fluorene derivatives, triphenylamine derivatives such as TPD (N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1-biphenyl]-4,4'-diamine), 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)benzenamine]), HMTPD (4,4'-bis[N,N'-(3-tolyl)amino]-3,3'-dimethylbiphenyl), and the like.

[0066] The thickness of the hole transport region HTR may be from about 5 nm to about 1000 nm, for example, from about 10 nm to about 500 nm. The thickness of the hole injection layer HIL is, for example, from about 3 nm to about 100 nm, and the thickness of the hole transport layer HTL may be from about 3 nm to about 100 nm. For example, the thickness of the electron blocking layer EBL may be from 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 ranges as described above, sufficient hole transport characteristics can be obtained without a substantial increase in the driving voltage.

[0067] In addition to the substances described above, the hole transport region HTR further contains a charge generating substance to improve conductivity. The charge generating substance is uniformly or non-uniformly dispersed in the hole transport region HTR. The charge generating substance is, for example, a p-dopant. The p-dopant may be one of, but not limited to, a quinone derivative, a metal oxide, and a cyano group-containing compound. For example, examples of the p-dopant include 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, but are not limited thereto.

[0068] As described above, in addition to the hole transport layer HTL and the hole injection layer HIL, the hole transport region HTR may further include at least one of a hole buffer layer (not shown) and an electron blocking layer EBL. The hole buffer layer (not shown) compensates 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 (not shown), a substance that can be contained in the hole transport region HTR is used. The electron blocking layer EBL is a layer that serves to prevent the injection of electrons from the electron transport region ETR into the hole transport region HTR.

[0069] 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 single-layer structure composed of a single substance, a single-layer structure composed of a plurality of different substances, or a multilayer structure having a plurality of layers composed of a plurality of different substances.

[0070] In the organic electroluminescent device 10 according to one embodiment, the light-emitting layer EML contains a plurality of light-emitting materials of different types. The organic electroluminescent device 10 includes a first host and a second host that are different from each other, and a first dopant and a second dopant that are different from each other.

[0071] The light-emitting layer EML of the organic electroluminescent device 10 according to one embodiment includes a host having a first emission start wavelength, a first dopant having a second emission start wavelength, and a second dopant having a third emission start wavelength. The host includes a first host and a second host different from the first host. The host includes a first host having a hole-transporting partial structure and a second host having an electron-transporting partial structure. In the light-emitting layer EML of the organic electroluminescent device 10 according to one embodiment, the host is one in which the first host and the second host form an exciplex.

[0072] The light-emitting layer EML according to one embodiment includes a first host containing a carbazolyl group derivative partial structure. The first host is represented by the following chemical formula H-1.

Chemical formula

[0073] In Chemical formula H-1, L 1 is a single bond, a substituted or unsubstituted arylene group having 6 or more and 30 or less ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 or more and 30 or less ring-forming carbon atoms. Also, Ar 1 is a substituted or unsubstituted aryl group having 6 or more and 30 or less ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 or more and 30 or less ring-forming carbon atoms.

[0074] In Chemical Formula H-1, a and b are each independently an integer of 0 or more and 4 or less, and R 1 and R 2 are each independently 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. On the other hand, if a and b are each an integer of 2 or more, a plurality of R 1 and a plurality of R 2 may all be the same or at least one may be different. For example, in Chemical Formula H-1, a and b may be 0. In this case, the carbazolyl group is unsubstituted.

[0075] In Chemical Formula H-1, L 1 may be a single bond, a phenylene group, a divalent biphenylylene group, a divalent carbazolylene group, etc., but the present embodiment is not limited thereto. Also, Ar 1 may be a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted biphenylyl group, etc., but the present embodiment is not limited thereto.

[0076] In the organic electroluminescent element 10 according to one embodiment, the light-emitting layer contains a compound represented by the following Chemical Formula H-2 as a second host.

Chemical Formula

[0077] In Chemical Formula H-2, Z 1 to Z 3 are each independently CR y or N, and R y and R 11 to R 13 are each independently a hydrogen atom, a deuterium atom, a cyano group, a substituted or unsubstituted silyl 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.

[0078] For example, chemical formula H-2 may be represented by the following chemical formula H-2a or chemical formula H-2b. [Chemical formula] ···(Chemical formula H-2a) [Chemical formula] ···(Chemical formula H-2b)

[0079] In chemical formula H-2a and chemical formula H-2b, R 11 ~R 13 are each independently a hydrogen atom, a deuterium atom, a cyano group, a substituted or unsubstituted silyl 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.

[0080] Also, in chemical formula H-2b, R y1 ~R y3 are each independently a hydrogen atom, a deuterium atom, a cyano group, a substituted or unsubstituted silyl 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. Also, in chemical formula H-2b, R 11 ~R 13 , and R y1 ~R y3 at least one of is a cyano group, an aryl group having 6 to 30 ring-forming carbon atoms containing at least one cyano group as a substituent, or a heteroaryl group having 2 to 30 ring-forming carbon atoms containing at least one cyano group as a substituent.

[0081] That is, the second host represented by chemical formula H-2a contains a triazine partial structure, and the second host represented by chemical formula H-2b contains at least one cyano group.

[0082] In chemical formula H-2a, R 11 ~R 13Each may independently be a substituted or unsubstituted phenyl group, a substituted or unsubstituted carbazolyl group, etc., but is not limited thereto.

[0083] In Chemical Formula H-2b, R 11 ~R 13 , and R y1 ~R y3 Any one of them may be substituted with a cyano group, or at least one of R 11 ~R 13 , and R y1 ~R y3 may be a heteroaryl group having 2 to 30 ring-forming carbons substituted with at least one cyano group. The heteroaryl group having 2 to 30 ring-forming carbons substituted with at least one cyano group may further contain a substituent other than the cyano group, and the substituent is a substituted or unsubstituted silyl group, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbons, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbons.

[0084] The organic electroluminescent device 10 according to one embodiment simultaneously includes a first host represented by Chemical Formula H-1 and a second host represented by Chemical Formula H-2 in the light-emitting layer EML, and includes a first dopant and a second dopant described later in the light-emitting layer EML, thereby exhibiting excellent luminous efficiency and long-life characteristics. In particular, in the light-emitting layer EML of the organic electroluminescent device 10 according to one embodiment, the host is one in which the first host represented by Chemical Formula H-1 and the second host represented by Chemical Formula H-2 form an exciplex.

[0085] Among the two host materials simultaneously included in the light-emitting layer EML, the first host is a hole-transporting host, and the second host is an electron-transporting host. The organic electroluminescent device 10 includes both a first host having excellent hole-transporting characteristics and a second host having excellent electron-transporting characteristics in the light-emitting layer EML, and efficient energy transfer to the dopant compound described later is possible.

[0086] The light-emitting layer EML contains an organometallic complex having Ir (iridium), Ru (ruthenium), Pt (platinum), Pd (palladium), Cu (copper), rhodium (Rh), or Os (osmium) as a central metal atom and ligands bonded to the central metal atom as a first dopant. In the organic electroluminescent device 10 according to one embodiment, the light-emitting layer contains a compound represented by the following chemical formula D-1 as the first dopant.

Chemical formula

[0087] In Chemical formula D-1, M is a metal atom. M is Pt, Pd, Cu, Os, Ir, Ru, or Rh.

[0088] In Chemical formula D-1, Q 1 ~Q 4 are each independently C or N.

[0089] In Chemical formula D-1, C1 to C4 are each independently a substituted or unsubstituted hydrocarbon ring having 5 to 30 ring-forming carbon atoms or a substituted or unsubstituted heterocyclic ring having 2 to 30 ring-forming carbon atoms.

[0090] JPEG0007691797000023.jpg65135

[0091] In Chemical formula D-1, e1 to e3 are each independently 0 or 1. If e1 is 0, C1 and C2 are not bonded to each other. If e2 is 0, C2 and C3 are not bonded to each other. If e3 is 0, C3 and C4 are not bonded to each other.

[0092] R 21 ~R 26Each is independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group having 1 to 20 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, and may combine with adjacent groups to form a ring. For example, R 21 ~R 26 If it is an alkyl group, it may be a methyl group, an isopropyl group, or a tert-butyl group. R 21 ~R 26 If it is an amino group, it may be a dimethylamino group. R 21 ~R 26 If it is a halogen atom, it may be a fluorine atom (F).

[0093] d1 to d4 are each independently an integer of 0 or more and 4 or less. If d1 to d4 are each an integer of 2 or more, a plurality of R 21 ~R 24 may all be the same or at least one may be different.

[0094] m is 1 or 2. If M is Pt, Pd, Cu, or Os, m is 1. If M is Ir, Ru, or Rh, m is 1 or 2 and e2 is 0.

[0095] For example, Chemical Formula D-1 may be represented by the following Chemical Formula D-1a.

Chemical Formula

[0096] In Chemical Formula D-1a, C1 to C4, Q 1 ~Q 4 、R 21 ~R 24 、d1 to d4, L 22 、and e2 are applied with the same content as that described in Chemical Formula D-1.

[0097] In Chemical Formula D-1a, C1 to C4 may each independently be a substituted or unsubstituted hydrocarbon ring or a substituted or unsubstituted heterocycle, each represented by any one of the following C-1 to C-3.

Chemical Structure

[0098] JPEG0007691797000026.jpg49135

[0099] JPEG0007691797000027.jpg29130

[0100] For example, Chemical Formula D-1 may be represented by the following Chemical Formula D-1b.

Chemical Structure

[0101] In Chemical Formula D-1b, X 1 ~X 4 、Y 1 ~Y 4 、and Z 1 ~Z 4 are each independently CR n or N. Also, R p 、R q 、and R n are each independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted hydrocarbon ring group having 5 to 30 ring-forming carbon atoms, a substituted heterocycle having 2 to 30 ring-forming carbon atoms, or a substituted or unsubstituted amino group, and adjacent groups may combine with each other to form a ring. In Chemical Formula D-1b, as ring-forming atoms, X 1 ~X 4 、Y 1 ~Y 4 、and Z 1 ~Z 4The six-membered rings each independently are a substituted or unsubstituted benzene ring, a substituted or unsubstituted pyridine ring, a substituted or unsubstituted pyrimidine ring, or a substituted or unsubstituted triazine ring.

[0102] The first dopant represented by the above-described Chemical Formula D-1a or Chemical Formula D-1b is a phosphorescent dopant.

[0103] The organic electroluminescent device 10 according to one embodiment includes a second dopant in addition to the first dopant represented by the above-described Chemical Formula D-1 in the light-emitting layer EML. The second dopant is a fluorescent dopant. The second dopant is a blue light-emitting material.

[0104] In the organic electroluminescent device 10, the light-emitting layer includes a compound represented by the following Chemical Formula D-2a or Chemical Formula D-2b as the second dopant.

Chemical formula

Chemical formula

[0105] In Chemical Formula D-2a, X 1 and X 2 are each independently NR m or O, and R m is a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 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. In Chemical Formula D-2a, R 31 ~R 41Each is independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted boryl group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkyl group having 1 to 20 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, and adjacent groups may combine with each other to form a ring.

[0106] For example, in Chemical Formula D-2a, R 31 ~R 41 Each is independently a hydrogen atom, a substituted or unsubstituted phenyl group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylboryl group, or a substituted or unsubstituted arylboryl group.

[0107] In Chemical Formula D-2a, R 39 and R 40 may combine with each other to form a heterocycle. R 39 and R 40 The condensed heterocycle formed by their combination contains heteroatoms such as B, O, or N. Further, the condensed heterocycle may or may not be substituted with a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group.

[0108] The second dopant represented by Chemical Formula D-2a may be represented by any one of the following Chemical Formulas D-2a-1 to D-2a-4.

Chemical Formula

Chemical Formula

Chemical Formula

Chem.

[0109] In chemical formulas D-2a-1 to D-2a-4, R m1 ~R m4 are each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 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. Also, R 1 ~R 18 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted boryl group, a substituted or unsubstituted oxy group, a substituted or unsubstituted alkyl group having 1 to 20 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, and adjacent groups may combine with each other to form a ring.

[0110] For example, R m1 ~R m4 may each independently be a hydrogen atom or a substituted or unsubstituted phenyl group. Also, R 1 ~R 18 may each independently be a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted carbazolyl group, or a substituted or unsubstituted arylamino group having 6 to 20 ring-forming carbon atoms. However, this embodiment is not limited thereto.

[0111] In chemical formula D-2b, L 2 is a single bond, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. For example, L 2may be a single bond, or a substituted or unsubstituted phenylene group.

[0112] In Chemical Formula D-2b, D 1 may be represented by the following Chemical Formula D-2-1 or Chemical Formula D-2-2.

Chem.

Chem.

[0113] In Chemical Formula D-2-1 and Chemical Formula D-2-2, L 3 and L 4 are each independently a single bond, or a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms. For example, L 3 and L 4 may each independently be a single bond, or a substituted or unsubstituted phenylene group.

[0114] R 42 ~R 59 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a substituted or unsubstituted alkyl group having 1 to 15 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. Alternatively, R 42 ~R 59 may combine with adjacent groups to form a ring.

[0115] Y 1 is a single bond, CRaRb, SiRcRd, GeReRf, NRg, O, or S. In one embodiment, Y 1 is a single bond, CRaRb, NRg, or O.

[0116] Ra to Rg are each independently a substituted or unsubstituted alkyl group having 1 to 15 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. Ra and Rb, Rc and Rd, and Re and Rf may be bonded to each other to form a ring.

[0117] In Chemical Formula D-2b, A 1 may be represented by the following Chemical Formula D-2-3 to Chemical Formula D-2-10.

Chem.

Chem.

Chem.

Chem.

Chem.

Chem.

Chem.

Chem.

[0118] In Chemical Formula D-2-3, Y 2 is C=O, or S(=O) 2is as follows. In Chemical Formula D-2-4, Y 3 is C=O or O. In Chemical Formula D-2-5, Y 4 and Y 5 are each independently substituted O or S. In Chemical Formula D-2-8, Y 6 and Y 7 are each independently N or CQ 12 In Chemical D-2-10, Y 8 is O or NQ 13 is as follows.

[0119] In Chemical Formulas D-2-3 to D-2-10, Q 1 to Q 13 are each independently a substituted or unsubstituted alkyl group having 1 to 15 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.

[0120] In Chemical Formulas D-2-3 to D-2-10, n1, n4, and n6 are each independently 0 or more and 4 or less, n3, n5, n7, n8, and n10 are each independently an integer of 0 or more and 3 or less, n2 is an integer of 0 or more and 5 or less, and n9 is an integer of 0 or more and 2 or less. If n1 to n10 are each an integer of 2 or more, a plurality of Q 1 to Q 10 may all be the same or at least one may be different.

[0121] The organic electroluminescent device 10 according to one embodiment includes a first dopant represented by Chemical Formula D-1 described above in the light-emitting layer EML and a second dopant represented by Chemical Formula D-2a or Chemical Formula D-2b. That is, the organic electroluminescent device 10 shows excellent luminous efficiency and improved device lifetime characteristics by simultaneously including the first dopant and the second dopant.

[0122] The lowest triplet excitation energy level (T1 level) of the first dopant is equal to or higher than the lowest triplet excitation energy level (T1 level) of the second dopant. The lowest triplet excitation energy level of the host is equal to or higher than the lowest triplet excitation energy level of the second dopant. In one embodiment, the first dopant serves as an assistant dopant that transfers the energy of the host to the second dopant. Further, the second dopant is a luminescent dopant that is excited by the energy transferred from the host and the first dopant and emits light. In one embodiment, the lowest triplet excitation energy level of the host is equal to or higher than the lowest triplet excitation energy level of each of the first dopant and the second dopant, and the lowest triplet excitation energy level of the second dopant is smaller than the lowest triplet excitation energy level of the host and the lowest triplet excitation energy level of the first dopant, respectively. Here, the lowest triplet excitation energy level (T1 level) is calculated by measuring the low-temperature luminescence spectrum of a single film, obtaining the onset wavelength, and converting it into an energy level.

[0123] In one embodiment, the second dopant is a thermally activated delayed fluorescence (TADF) dopant. That is, in one embodiment, the second dopant is K RISC (inverse intersystem crossing constant) is 10 3 S -1 or more, or f (oscillation strength) is 0.1 or more, and thermally activated delayed fluorescence is likely to occur.

[0124] In one embodiment, the second dopant is a luminescent dopant that emits blue light, and the emission layer EML emits fluorescent light. More specifically, the emission layer EML emits delayed fluorescence of blue light.

[0125] In one embodiment, the first dopant serving as an auxiliary dopant accelerates the delayed fluorescence of the second dopant. Therefore, the light-emitting efficiency of the light-emitting layer in one embodiment is improved. Further, if the delayed fluorescence is accelerated, the excitons formed in the light-emitting layer EML do not accumulate inside the light-emitting layer EML and emit light quickly, so that the degradation of the device is reduced. Therefore, the lifespan of the organic electroluminescent device 10 in one embodiment is extended.

[0126] In the organic electroluminescent device 10 of one embodiment, the light-emitting layer EML includes all of the above-described first host, second host, first dopant, and second dopant. Based on the total weight of the first host, second host, first dopant, and second dopant, the content of the first dopant is 10 wt% or more and 15 wt% or less, and the content of the second dopant is 1 wt% or more and 5 wt% or less.

[0127] If the contents of the first dopant and the second dopant satisfy the above-described ratios, the first dopant can efficiently transfer energy to the second dopant, thereby improving the light-emitting efficiency and the device lifespan.

[0128] In the light-emitting layer EML, the contents of the first host and the second host are the remainder excluding the weights of the above-described first dopant and second dopant. For example, in the light-emitting layer EML, the contents of the first host and the second host are about 80 wt% or more and about 89 wt% or less based on the total weight of the first host, second host, first dopant, and second dopant. In the total weight of the first host and the second host, the weight ratio of the first host and the second host is about 7:3 to 3:7.

[0129] If the contents of the first host and the second host satisfy the above-described ratios, the charge balance characteristics in the light-emitting layer EML are improved, so that the light-emitting efficiency and the device lifespan are improved. If the contents of the first host and the second host deviate from the above-described ratios, the charge balance in the light-emitting layer EML is disrupted, the light-emitting efficiency decreases, and the device is likely to deteriorate.

[0130] If the first host, the second host, the first dopant, and the second dopant included in the light-emitting layer EML satisfy the above-described content ratio ranges, excellent luminous efficiency and long life can be achieved.

[0131] The organic electroluminescent device 10 of one embodiment includes all of a first host, a second host, a first dopant, and a second dopant, and the light-emitting layer EML includes a combination of two host materials and two dopant materials. In the organic electroluminescent device 10 of one embodiment, the light-emitting layer EML simultaneously includes two different hosts, a first dopant including an organometallic complex, and a second dopant that emits delayed fluorescence, thereby exhibiting excellent luminous efficiency and life characteristics.

[0132] In one embodiment, the first host represented by the chemical formula H-1 may be any one of the compounds shown in the following first compound group. The light-emitting layer EML may include at least one of the compounds HT-01 to HT-17 shown in the following first compound group as the first host material.

[0133] [First Compound Group] [Chemical Formula] [Chemical Formula] [Chemical Formula] [Chemical Formula] [Chemical Formula]

[0134] In one embodiment, the second host represented by Chemical Formula H-2 may be any one of the compounds shown in the following Group 2-1 compounds and Group 2-2 compounds. The light-emitting layer EML may contain at least one of the compounds shown in the following Group 2-1 compounds and Group 2-2 compounds as the second host material. The Group 2-1 compounds are second host materials represented by Chemical Formula H-2a, and the Group 2-2 compounds are second host materials represented by Chemical Formula H-2b.

[0135] [Group 2-1 compounds] [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula]

[0136] [Group 2-2 compounds] [Chemical formula] JPEG0007691797000056.jpg58117 [Chemical formula] [Chemical formula]

[0137] In one embodiment, the light-emitting layer EML may contain at least one of the compounds shown in the following Compound Group 3-1 and Compound Group 3-2 as a first dopant substance. Compound Group 3-1 is a first dopant substance represented by chemical formula D-1a, and Compound Group 3-2 is a first dopant substance represented by chemical formula D-1b.

[0138] [Compound Group 3-1] [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula]

[0139] [Compound Group 3-2] [Chemical formula] [Chemical formula] [Chemical formula]

[0140] In the aforementioned compound 3-2 compound group, in AD2-1 to AD2-4, AD2-13 to AD2-16, and AD2-25 to AD2-28, R is independently a hydrogen atom, a methyl group, an isopropyl group, a tert-butyl group, or a dimethylamino group respectively.

[0141] In one embodiment, the second dopant represented by chemical formula D-2 is represented by any one of the compounds shown in the following Compound Group 4-1 or Compound Group 4-2. The light-emitting layer EML contains at least one of the compounds shown in the following Compound Group 4-1 or Compound Group 4-2 as the second dopant substance. Compound Group 4-1 is the second dopant substance represented by chemical formula D-2a, and Compound Group 4-2 is the second dopant substance represented by chemical formula D-2b.

[0142] [Compound Group 4-1] [Chemical formula] [Chemical formula] [Chemical formula]

[0143] [Compound Group 4-2] [Chemical formula] [Chemical formula] [Chemical formula]

[0144] In the organic electroluminescent element 10 according to one embodiment, the host has a first emission start wavelength, the first dopant has a second emission start wavelength, and the second dopant has a third emission start wavelength. The third emission start wavelength of the second dopant is greater than the first emission start wavelength and the second emission start wavelength. More specifically, the third emission start wavelength of the second dopant is greater than the second emission start wavelength of the first dopant, and the second emission start wavelength of the first dopant is greater than the first emission start wavelength of the host.

[0145] In this specification, the emission start wavelength is defined as the x-intercept value when a tangent line to the normalized emission spectrum is drawn from the point where the light intensity is 0.5 in the normalized emission spectrum. Also, in this specification, the light absorption and emission spectrum is normalized by dividing by the maximum value of the first peak after dissolving the light-emitting substance in an organic solvent and measuring the absorption and emission spectra.

[0146] Figures 6A to 6F are graphs showing the emission spectra normalized by the wavelengths of the host, the first dopant, and the second dopant according to one embodiment of the present invention.

[0147] In Figures 6A to 6F, the x-intercept of the tangent line from the point where the light intensity of the normalized emission spectrum of the host is 0.5 is defined as the first emission start wavelength (x 1 ). In Figures 6A to 6F, the x-intercept of the tangent line from the point where the light intensity of the normalized emission spectrum of the first dopant is 0.5 is defined as the second emission start wavelength (x 2 ). In Figures 6A to 6F, the x-intercept of the tangent line from the point where the light intensity of the normalized emission spectrum of the second dopant is 0.5 is defined as the third emission start wavelength (x 3 ).

[0148] Referring to Figures 6A to 6F, the third emission start wavelength (x 3 ) of the second dopant according to one embodiment of the present invention is the first emission start wavelength (x 1 ) of the host and the second emission start wavelength (x 2) has a value larger than that in 1 ). In one embodiment of the present invention, the first light emission start wavelength (x 2 ) is smaller than the second light emission start wavelength (x 3 ) and the third light emission start wavelength (x 2 ), the second light emission start wavelength (x 1 ) is larger than the first light emission start wavelength (x 3 ), and has a value smaller than the third light emission start wavelength (x 1 ). That is, in the light emitting layer according to one embodiment of the present invention, the values of the first light emission start wavelength (x 2 ), the second light emission start wavelength (x 3 ), and the third light emission start wavelength (x

[0149] ) increase in this order. As shown in FIG. 6A, when the emission peak wavelength of the host is the smallest, the emission peak wavelength of the first dopant is larger than the emission peak wavelength of the host, and the emission peak wavelength of the second dopant is the largest, the first light emission start wavelength (x 1 ), the second light emission start wavelength (x 2 ), and the third light emission start wavelength (x 3 ) increase in this order. Different from this, as shown in FIG. 6B, even when the emission peak wavelength of the host is the smallest and the emission peak wavelength of the first dopant is the largest, the first light emission start wavelength (x 1 ), the second light emission start wavelength (x 2 ), and the third light emission start wavelength (x 3 ) increase in this order. As shown in FIG. 6C, even when the emission peak wavelength of the host is larger than the emission peak wavelength of the first dopant and the emission peak wavelength of the second dopant has the largest value, the first light emission start wavelength (x 1 ), the second light emission start wavelength (x 2 ), and the third light emission start wavelength (x 3 ) increase in this order. As shown in FIG. 6D, even when the emission peak wavelength of the second dopant is the smallest and the emission peak wavelength of the first dopant is the largest, the first light emission start wavelength (x 1 ), the second light emission start wavelength (x 2 ), and the third light emission start wavelength (x 3) The values increase in the order of. As shown in FIG. 6E, even when the emission peak wavelength of the host is the largest and the emission peak wavelength of the first dopant is the smallest, the first emission start wavelength (x 1 ), the second emission start wavelength (x 2 ), and the third emission start wavelength (x 3 ) The values increase in the order of. As shown in FIG. 6F, even when the emission peak wavelength of the second dopant is the smallest, the emission peak wavelength of the host is the largest, and the wavelengths at which the light intensities of the normalized emission spectra of the host, the normalized emission spectrum of the first dopant, and the normalized emission spectrum of the second dopant are each 0.5 are close to each other, the first emission start wavelength (x 1 ), the second emission start wavelength (x 2 ), and the third emission start wavelength (x 3 ) The values increase in the order of.

[0150] In one embodiment of the present invention, the first emission start wavelength is 380 nm or more and 430 nm or less, the second emission start wavelength is 400 nm or more and 450 nm or less, and the third emission start wavelength is 410 nm or more and 460 nm or less.

[0151] In one embodiment of the present invention, the emission start wavelength and the onset energy are in an inverse proportional relationship and satisfy the relationship of the following formula 1. Emission start energy of host > Emission start energy of first dopant > Emission start energy of second dopant... (Formula 1) In addition, in this specification, the emission start energy is a concept that is inversely proportional to the emission start wavelength, and is obtained by dividing the absolute value of the photon energy by the emission start wavelength.

[0152] In the organic electroluminescent element 10 according to one embodiment of the present invention, the light emitting layer EML includes a host having a first emission start wavelength, a first dopant having a second emission start wavelength, and a second dopant having a third emission start wavelength, and the third emission start wavelength has a value larger than the first emission start wavelength and the second emission start wavelength. More specifically, the third emission start wavelength is larger than the second emission start wavelength, and the second emission start wavelength has a value larger than the first emission start wavelength.

[0153] In an organic electroluminescent device according to an embodiment, the emission start wavelength of the second dopant, which is a light emitter, is the largest, the emission start wavelength of the first dopant that functions as an auxiliary dopant is smaller than the emission start wavelength of the second dopant, and the emission start wavelength of the host has the smallest value. Thus, energy transfer from the host to the first dopant and from the first dopant to the second dopant is easily achieved, and thereby the organic electroluminescent device exhibits excellent luminous efficiency and lifetime characteristics.

[0154] FIGS. 7A and 7B are graphs showing the light emission spectrum and the light absorption spectrum according to the wavelength of the second dopant according to an embodiment of the present invention.

[0155] Referring to FIGS. 7A and 7B, in an organic electroluminescent device 10 according to an embodiment, the intensity of the normalized light at the intersection point (c, c') of the normalized light absorption spectrum and the normalized emission spectrum of the second dopant is 0.5 or more. Further, in the organic electroluminescent device 10 according to an embodiment, the interval (n, n') between the peak of the normalized light absorption spectrum and the peak of the normalized emission spectrum of the second dopant is 50 nm or less. By satisfying this condition for the light absorption spectrum and the emission spectrum of the second dopant, energy transfer from the host and the first dopant to the second dopant is easily achieved, and thereby the organic electroluminescent device exhibits excellent luminous efficiency and lifetime characteristics.

[0156] On the other hand, 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 sequentially stacked. For example, the organic electroluminescent device 10 including a plurality of light emitting layers may emit white light. The organic electroluminescent device 10 including a plurality of light emitting layers is an organic electroluminescent device having a tandem structure. When the organic electroluminescent device 10 includes a plurality of light emitting layers, at least one light emitting layer EML includes all of the first host, the second host, the first dopant, and the second dopant as described above.

[0157] In the organic electroluminescent device 10 of an embodiment shown in FIGS. 1 to 5, the electron transport region ETR is provided above the light emitting 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 the present embodiment is not limited thereto.

[0158] The electron transport region ETR has a single layer structure composed of a single substance, a single layer structure composed of a plurality of different substances, or a multilayer structure having a plurality of layers composed of a plurality of different substances.

[0159] 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 composed of an electron injection substance and an electron transport substance. Further, the electron transport region ETR may have a structure of a single layer 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.

[0160] The electron transport region ETR is formed by 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, and a laser thermal transfer method (Laser Induced Thermal Imaging, LITI).

[0161] When the electron transport region ETR includes an electron transport layer ETL, the electron transport region ETR includes an anthracene-based compound. However, it is not limited thereto, and the electron transport region may be, 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-phenylbenzimidazolyl-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), Bebq 2 (Beryllium bis(benzoquinolin-10-olato), ADN(9,10-di(naphthalen-2-yl)anthracene), and mixtures thereof may be included. The thickness of the electron transport layer ETL may be from about 10 nm to about 100 nm, for example from about 15 nm to about 50 nm. When the thickness of the electron transport layer HTL satisfies the range as described above, sufficient electron transport characteristics can be obtained without a substantial increase in the driving voltage.)

[0162] When the electron transport region ETR includes an electron injection layer EIL, the electron transport region ETR may contain metal halides such as LiF, NaCl, CsF, RbCl, RbI, CuI, lanthanoid metals such as Yb, Li 2Metal oxides such as O and BaO, or LiQ (lithium quinolate) etc. may be used, but are not limited thereto. The electron injection layer EIL also consists of a substance in which an electron transporting material and an insulating organo metal salt are mixed. The organo metal salt is a substance having an energy band gap of about 4 eV or more. Specifically, 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, about 0.3 nm to about 9 nm. If the thickness of the electron injection layer EIL satisfies the range as described above, sufficient electron injection characteristics can be obtained without a substantial increase in the driving voltage.

[0163] As described above, the electron transport region ETR may include a hole blocking layer HBL. The hole blocking layer HBL may include, for example, at least one of BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) and Bphen (4,7-diphenyl-1,10-phenanthroline), but is not limited thereto.

[0164] The second electrode EL2 is provided on the electron transport region ETR. The second electrode EL2 is 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, for example, ITO, IZO, ZnO, ITZO, etc. The thickness of the second electrode EL2 may be, for example, about 100 nm to about 1000 nm, or about 100 nm to about 300 nm.

[0165] If the second electrode EL2 is a semi-transmissive electrode or a reflective electrode, the second electrode EL2 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 containing these (for example, an alloy of Ag and Mg). Further, the second electrode EL2 may have a multi-layer structure including a reflective film or a semi-transmissive film made of the aforementioned substances, and a transparent conductive film made of ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), ITZO (indium tin zinc oxide), etc.

[0166] 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.

[0167] Referring to FIG. 4, an organic electroluminescent device 10 according to an embodiment further includes a buffer layer BFL between a light-emitting layer EML and an electron transport region ETR. The buffer layer BFL adjusts the concentration of excitons generated from the light-emitting layer EML. For example, the buffer layer BFL includes a part of the materials of the light-emitting layer EML. The buffer layer BFL includes a host material among the materials of the light-emitting layer EML. The lowest triplet excitation energy level of the buffer layer BFL material is adjusted to be equal to or higher than the lowest triplet excitation energy level of the second dopant, or equal to or lower than the lowest triplet excitation energy level of the second dopant, depending on the combination of the host and dopant materials included in the light-emitting layer EML.

[0168] Referring to FIG. 5, a capping layer CPL may be further disposed on the second electrode EL2 of the organic electroluminescent device 10 according to an embodiment. The capping layer CPL may include, for example, α-NPD, NPB, TPD, m-MTDATA, Alq3, CuPc, TPD15 (N4,N4,N4’,N4’-tetra(biphenyl-4-yl)biphenyl-4,4’-diamine), TCTA (4,4’,4”-tris(carbazol-9-yl)triphenylamine), N,N’-bis(naphthalen-1-yl), etc.

[0169] The compounds of the above-described embodiment may be included as materials for the organic electroluminescent device 10 in functional layers other than the light-emitting layer EML. The organic electroluminescent device 10 according to an embodiment of the present invention may include the above-described compound in at least one functional layer disposed between the first electrode EL1 and the second electrode EL2, or in a capping layer CPL disposed on the second electrode EL2.

[0170] As described above, the organic electroluminescent device 10 according to an embodiment of the present invention optimizes the combination of the host material and the dopant material of the light-emitting layer, and exhibits excellent luminous efficiency and long-life characteristics. Further, the organic electroluminescent device 10 of one embodiment exhibits high-efficiency and long-life characteristics in the blue wavelength region.

Examples

[0171] Hereinafter, with reference to Examples and Comparative Examples, the compounds and the organic electroluminescent devices according to an embodiment of the present invention will be described in detail. Further, the Examples shown below are examples for helping the understanding of the present invention, and the scope of the present invention is not limited thereto.

[0172] (Fabrication of Organic Electroluminescent Device) For the organic electroluminescent devices of the Examples and Comparative Examples, an ITO glass substrate was cut into a size of about 50 mm × 50 mm × 0.5 mm, ultrasonically cleaned with isopropyl alcohol and distilled water for 10 minutes each, then irradiated with ultraviolet rays for about 10 minutes and exposed to ozone for cleaning, and then installed in a vacuum evaporation apparatus. Next, a hole injection layer HIL with a thickness of about 10 nm was formed with 2-MTDATA, and a hole transport layer HTL with a thickness of about 70 nm was formed with NPB. Next, a first host, a second host, a first dopant, and a second dopant according to an embodiment were co-evaporated to form a light-emitting layer EML with a thickness of 30 nm, and an electron transport layer ETL with a thickness of 30 nm was formed with the following compound ETL1. Next, a second electrode EL2 with a thickness of 120 nm was formed with Al. Each layer was formed by a vacuum evaporation method. The concentration of the first dopant at the time of evaporating the light-emitting layer EML was 15%, and the concentration of the second dopant was 1%.

Chemical Formula

[0173] The combinations of the light-emitting layer materials used in the examples and comparative examples are shown in Table 1 below. [Table 1]

[0174] In the devices of the examples and comparative examples, the lowest triplet excitation energy (T1) of the host, the lowest triplet excitation energy (T1) of the first dopant, the lowest triplet excitation energy (T1) of the second dopant, the light emission start wavelength of the host (the first light emission start wavelength), the light emission start wavelength of the first dopant (the second light emission start wavelength), the light emission start wavelength of the second dopant (the third light emission start wavelength), the normalized light intensity at the intersection (wavelength intersection) of the normalized light absorption spectrum and the normalized light emission spectrum of the second dopant, and the absorption / emission peak distance are shown in Table 2. When there are two or more types of hosts, the two types of hosts form an exciplex. In Table 2, the T1 wavelength and the emission start wavelength of the exciplex are measured and described. [Table 2]

[0175] (Characteristics Evaluation of Organic Electroluminescent Devices) The characteristics evaluation of the fabricated organic electroluminescent devices was carried out using a luminance orientation characteristic measuring device. To evaluate the characteristics of the organic electroluminescent devices according to the examples and comparative examples, the efficiency and the lifetime (T 95 ) were measured. In Table 3, the luminous efficiency (cd / A) at a current density of 10 mA / cm 2 and a luminance of 1000 cd / m 2 is shown for the fabricated organic electroluminescent devices. Also, the device lifetime (T 2 ), which is the time required for the luminance to decrease from the 1000 cd / m 95 reference to the 95% level, is shown. The device lifetime (T 95 ) was measured by continuous driving at a current density of 10 mA / cm 2 , and the unit is time (hour).

Table 3

[0176] Referring to the results in Table 3, in the case of an embodiment, including all of the first host, the second host, the first dopant, and the second dopant like the light-emitting layer, and the emission start wavelength of the second dopant (the third emission start wavelength) having a value larger than the emission start wavelength of the host (the first emission start wavelength) and the emission start wavelength of the first dopant (the second emission start wavelength), it can be seen that in the case of the examples, at least one of the light-emitting element efficiency and the element lifetime is improved as compared with the comparative examples.

[0177] In the cases of Comparative Examples 1, 2, 4 to 9, by not including any one of the first host, the second host, the first dopant, and the second dopant, it can be seen that at least one of the efficiency and the lifetime decreases as compared with the elements of the examples. Also, in the cases of Comparative Examples 3 and 10 to 16, although including all of the first host, the second host, the first dopant, and the second dopant, at least one of the emission start wavelength of the first dopant (the second emission start wavelength) and the emission start wavelength of the host (the first emission start wavelength) has a larger value than the emission start wavelength of the second dopant (the third emission start wavelength), and it can be seen that at least one of the light-emitting efficiency and the element lifetime decreases as compared with the light-emitting elements of the examples.

[0178] In an organic electroluminescent device according to an embodiment, the emission start wavelength (third emission start wavelength) of the second dopant, which is a light emitter, is the largest, the emission start wavelength (second emission start wavelength) of the first dopant that functions as an auxiliary dopant is smaller than the emission start wavelength (third emission start wavelength) of the second dopant, and the emission start wavelength (first emission start wavelength) of the host is the smallest. By having these values, the energy transfer between the materials constituting the light-emitting layer is improved, and high luminous efficiency and long-life characteristics are exhibited. In addition, in an organic electroluminescent device according to an embodiment, the normalized light intensity at the wavelength intersection of the normalized light absorption spectrum and the normalized emission spectrum of the second dopant, which is a light emitter, is 0.5 or more. By this, the energy transfer from the host and the first dopant to the second dopant is improved, and high luminous efficiency and long-life characteristics are exhibited.

[0179] Although the preferred embodiments of the present invention have been described so far with reference to the preferred embodiments, those skilled in the art or those having ordinary knowledge in the relevant technical field should understand that the present invention can be variously modified and changed without departing from the spirit and technical scope of the present invention described in the claims below.

[0180] Therefore, the technical scope of the present invention should not be limited to the content described in the detailed description of the specification, but should be determined by the claims.

Explanation of Reference Numerals

[0181] 10: Organic electroluminescent device 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 facing the first electrode, and a light-emitting layer disposed between the first electrode and the second electrode, wherein the light-emitting layer includes a host having a first light emission start wavelength, a first dopant having a second light emission start wavelength, and a second dopant having a third light emission start wavelength different from that of the first dopant, wherein the third light emission start wavelength is greater than the first light emission start wavelength and the second light emission start wavelength, the host includes a first host and a second host different from the first host, the first host includes at least one of the compounds shown in the following first compound group, [First Compound Group] 【Chemical 1】 [Chemical Formula 2] 【Chemical Formula 3】 【Chemical Formula 4】 【Chemical Formula 5】 the second host includes at least one of the compounds shown in the following second-1 compound group or is represented by the following chemical formula H-2, when the second host is represented by the chemical formula H-2, the second host contains a cyano group, an organic electroluminescent element. [Second-1 Compound Group] 【Chemical Formula 6】 [Chemical Formula 7] 【Chemical Formula 8】 【Chemical Formula 9】 【Chemical 10】 【Chemical 11】 ... (Chemical formula H-2) (In the chemical formula H-2, Z １ to Z ３ are each independently CR ｙ and R ｙ and R １１ ~R １３ are each independently a hydrogen atom, a deuterium atom, a cyano group, a substituted or unsubstituted silyl 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. )

2. The organic electroluminescent device according to claim 1, wherein the normalized light intensity at the intersection of the normalized light absorption spectrum and the normalized emission spectrum of the second dopant is 0.5 or more.

3. The organic electroluminescent device according to claim 2, wherein the distance between the peak of the normalized light absorption spectrum and the peak of the normalized emission spectrum of the second dopant is 50 nm or less.

4. The organic electroluminescent device according to claim 1, wherein the lowest triplet excitation energy level of the second dopant is lower than the lowest triplet excitation energy levels of the host and the first dopant, respectively.

5. The organic electroluminescent device according to claim 1, wherein the first dopant includes an organometallic complex having Ir, Ru, Rh, Pt, Pd, Cu, or Os as a central metal atom.

6. The organic electroluminescent device according to claim 5, wherein the first dopant is represented by the following chemical formula D-1. 【Chemical Formula 12】 ... (Chemical formula D-1) (In the chemical formula D-1, M is Pt, Pd, Cu, Os, Ir, Ru, or Rh, Q １ ~Q ４ are each independently C or N, C1 to C4 are each independently a substituted or unsubstituted hydrocarbon ring having 5 or more and 30 or less ring-forming carbon atoms, or a substituted or unsubstituted heterocycle having 2 or more and 30 or less ring-forming carbon atoms, L ２１ ~L ２３ are each independently a single bond, 【Chem.】 a divalent alkyl group having 1 to 20 carbon atoms, which may be substituted or unsubstituted, an arylene group having 6 to 30 ring-forming carbon atoms, which may be substituted or unsubstituted, or a heteroarylene group having 2 to 30 ring-forming carbon atoms, which may be substituted or unsubstituted, e1 to e3 are each independently 0 or 1, R ２１ ~R ２６ each independently represents a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group having 1 to 20 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, and adjacent groups are bonded to each other either combine to form a ring or do not bond to each other, d1 to d4 are each independently an integer of 0 or more and 4 or less, if M is Pt, Pd, Cu, or Os, then m is 1, if M is Ir, Ru, or Rh, then m is 1 or 2 and e2 is 0.)

7. The organic electroluminescent element according to claim 1, wherein the second dopant is represented by the following chemical formula D-2a. 【Chemical 13】 ... (Chemical formula D-2a) (In the chemical formula D-2a, X １ and X ２ are each independently NR ｍ or O, and R ｍ is a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 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, R ３１ to R ４１ each independently represents a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted boryl group, a substituted or unsubstituted oxy group, a substituted or unsubstituted alkyl group having 1 to 20 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, and may combine with adjacent groups to form a ring or may not combine with each other.

8. The organic electroluminescent element according to claim 1, wherein the second dopant is represented by the following chemical formula D-2b. 【Chemical 14】 ... (Chemical formula D-2b) (In the chemical formula D-2b, L ２ is a single bond, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms, D １ is represented by the following chemical formula D-2-1 or chemical formula D-2-2, 【Chemical Formula 15】 ... (Chemical formula D-2-1) 【Chemical 16】 ... (Chemical formula D-2-2) In the chemical formula D-2-1 and the chemical formula D-2-2, L ３ and L ４ are each independently a single bond or a substituted or unsubstituted arylene group having 6 to 30 carbon atoms forming a ring, R ４２ to R ５９ are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted silyl group, a substituted or unsubstituted alkyl group having 1 to 15 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, and may combine with adjacent groups to form a ring or may not combine with each other, Y １ is a single bond, CRaRb, SiRcRd, GeReRf, NRg, O, or S, Ra to Rg are each independently an alkyl group having 1 to 15 carbon atoms, which may be substituted or unsubstituted, an aryl group having 6 to 30 ring-forming carbon atoms, which may be substituted or unsubstituted, or a heteroarylene group having 2 to 30 ring-forming carbon atoms, which may be substituted or unsubstituted, Ra and Rb, Rc and Rd, and Re and Rf either bond to each other to form a ring or do not bond to each other, A １ is represented by the following chemical formula D-2-3 and chemical formula D-2-10, 【Chemical 17】 ... (Chemical formula D-2-3) 【Chemical 18】 ... (Chemical formula D-2-4) 【Chemical Formula 19】 ... (Chemical formula D-2-5) 【Chemical 20】 ... (Chemical formula D-2-6) 【Chemical 21】 ... (Chemical formula D-2-7) 【Chemical 22】 ... (Chemical formula D-2-8) 【Chemical 23】 ... (Chemical formula D-2-9) 【Chemical 24】 ... (Chemical formula D-2-10) Y ２ is C=O, S(=O) ２ and Y ３ is C=O, or O, and Y ４ and Y ５ are each independently O, or S, Y ６ and Y ７ are each independently N, or CQ １２ and Y ８ is O or NQ １３ and Q １ to Q １３ are each independently a substituted or unsubstituted alkyl group having 1 to 15 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, n1, n4, and n6 are each independently 0 or more and 4 or less, n3, n5, n7, n8, and n10 are each independently an integer of 0 or more and 3 or less, n2 is an integer of 0 or more and 5 or less, n9 is an integer of 0 or more and 2 or less.)

9. The organic electroluminescent element according to claim 1, wherein the weight ratio of the first host and the second host is 7:3 to 3:

7.

10. Based on the total weight of the first host, the second host, the first dopant, and the second dopant, the content of the first dopant is 10 wt% or more and 15 wt% or less, The organic electroluminescent element according to claim 1, wherein the content of the second dopant is 1 wt% or more and 5 wt% or less.

11. The organic electroluminescent device according to claim 1, wherein the first dopant contains at least one of the compounds shown in the following Compound Group 3-1 or the following Compound Group 3-2. [Compound Group 3-1] 【Chemical Formula 25】 【Chemical 26】 【Chemical 27】 【Chemical Formula 28】 【Chemical 29】 【Chemical 30】 【Chemical 31】 【Chemical 32】 【Chemical 33】 [Compound Group 3-2] 【Chemical 34】 【Chemical 35】 【Chemical 36】 (In Compound AD2-1 to Compound AD2-4, Compound AD2-13 to Compound AD2-16, and Compound AD2-25 to Compound AD2-28, R is independently a hydrogen atom, a methyl group, an isopropyl group, a tert-butyl group, or a dimethylamino group.)

12. The organic electroluminescent device according to claim 1, wherein the second dopant contains at least one of the compounds shown in the following Compound Group 4-1 or the following Compound Group 4-2. [Compound Group 4-1] 【Chemical 37】 【Chemical Formula 38】 【Chemical Formula 39】 [Compound Group 4-2] 【Chemical 40】 【Chemical Formula 41】 【Chemical 42】

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