Organic electroluminescent device

Abstract

The organic electroluminescent device of the embodiment includes a first electrode, a second electrode, and an emission layer disposed between the first electrode and the second electrode, wherein the emission layer includes: a host having a first emission start wavelength; 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 each of the first emission start wavelength and the second emission start wavelength, and the device has improved emission efficiency and / or long-life characteristics.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority and benefit of Korean Patent Application No. 10 - 2019 - 0121391, filed on October 1, 2019, the entire content of which is incorporated herein by reference. Technical field

[0003] One or more aspects of embodiments of the present disclosure relate to an organic electroluminescent device, and more particularly, to an organic electroluminescent device including a plurality of light - emitting materials in an emission layer. Background art

[0004] Organic electroluminescent displays are being actively developed as image displays. An organic electroluminescent display is different from a liquid crystal display in that it is a so - called self - emissive display, in which holes and electrons injected from a first electrode and a second electrode, respectively, recombine in an emission layer, and a light - emitting material including an organic compound in the emission layer emits light to achieve display.

[0005] When applying an organic electroluminescent device to a display, it is desirable to reduce the driving voltage of the organic electroluminescent device and increase the emission efficiency and / or lifespan, and it is also desirable to develop materials for an organic electroluminescent device capable of stably achieving the above requirements.

[0006] Recently, in order to realize an organic electroluminescent device with high efficiency, materials capable of phosphorescent emission (which uses the energy of triplets) or delayed fluorescence emission (which uses the phenomenon of generating singlet excitons through the collision of triplet excitons (triplet - triplet annihilation, TTA)), and materials capable of thermally activated delayed fluorescence (TADF) using delayed fluorescence are being developed. Summary of the invention

[0007] One or more aspects of embodiments of the present disclosure relate to an organic electroluminescent device exhibiting excellent lifespan (service life) characteristics and emission efficiency.

[0008] One or more exemplary embodiments of the present disclosure provide an organic electroluminescent device including a first electrode; a second electrode opposite to the first electrode; and an emission layer disposed between the first electrode and the second electrode. The emission layer includes a host having a first light - emitting start wavelength; a first dopant having a second light - emitting start wavelength; and a second dopant different from the first dopant and having a third light - emitting start wavelength. The third light - emitting start wavelength is greater than each of the first light - emitting start wavelength and the second light - emitting start wavelength.

[0009] In an embodiment, the normalized light intensity at the intersection of the normalized light absorption spectrum and the normalized light emission spectrum of the second dopant may be about 0.5 or greater.

[0010] In an embodiment, the distance between the peak of the normalized optical absorption spectrum and the peak of the normalized optical emission spectrum of the second dopant may be about 50 nm or less.

[0011] In an embodiment, the second dopant may have a lower lowest triplet excitation energy level than each of the host and the first dopant (e.g., the lowest triplet excitation energy level may be lower).

[0012] In an embodiment, the host may include a first host and a second host, and the second host is different from the first host.

[0013] In an embodiment, the first host may be represented by Formula H-1:

[0014] [Formula H-1]

[0015]

[0016] In Formula H-1, L1 may be a direct bond, a substituted or unsubstituted arylene having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroarylene having 2 to 30 ring-forming carbon atoms; Ar1 may be a substituted or unsubstituted aryl having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroaryl having 2 to 30 ring-forming carbon atoms; "a" and "b" may each independently be an integer selected from 0 to 4; and R1 and R2 may each independently be a substituted or unsubstituted aryl having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroaryl having 2 to 30 ring-forming carbon atoms.

[0017] In an embodiment, the second host may be represented by Formula H-2:

[0018] [Formula H-2]

[0019]

[0020] In Formula H-2, Z1 to Z3 may each independently be CR y or N; and R y and R 11 to R 13 may each independently be a hydrogen atom, a deuterium atom, a cyano group, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroaryl having 2 to 30 ring-forming carbon atoms.

[0021] In an embodiment, the first dopant may include an organometallic complex including Ir, Ru, Rh, Pt, Pd, Cu or Os as a central metal element.

[0022] In an embodiment, the first dopant may be represented by Formula D-1:

[0023] [Formula D-1]

[0024]

[0025] In Formula D-1, M may be Pt, Pd, Cu, Os, Ir, Ru or Rh; Q1 to Q4 may each independently be C or N; C1 to C4 may each independently be 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; L 21 to L 23 may each independently be a direct bond, a substituted or unsubstituted divalent alkyl group having 1 to 20 carbon atoms, 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; e1 to e3 may each independently be 0 or 1; R 21 to R 26 may each independently be 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, or may each combine with an adjacent group to form a ring; d1 to d4 may each independently be an integer selected from 0 to 4; and when M is Pt, Pd, Cu or Os, "m" may be 1, and when M is Ir, Ru or Rh, "m" may be 2, and e2 may be 0; and refers to the connecting position.

[0026] In an embodiment, the second dopant may be represented by Formula D-2a:

[0027] [Formula D-2a]

[0028]

[0029] In Formula D-2a, X1 and X2 may each independently be NR m or O; R m may be 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; and R 31 to R 41Each may independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted boron 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 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, or may each combine with an adjacent group to form a ring.

[0030] In an embodiment, the second dopant may be represented by Formula D-2b:

[0031] [Formula D-2b]

[0032] D1-L2-A1.

[0033] In Formula D-2b, L2 may be a direct bond, a substituted or unsubstituted arylene having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroarylene having 2 to 30 carbon atoms for forming a ring; and D1 may be represented by Formula D-2-1 or Formula D-2-2:

[0034]

[0035] In Formula D-2-1 and Formula D-2-2, L3 and L4 may each independently be a direct bond or a substituted or unsubstituted arylene having 6 to 30 carbon atoms for forming a ring; R 42 to R 59 may each independently be 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 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, or each combine with an adjacent group to form a ring; Y1 may be a direct bond, CR a R b , SiR c R d , GeR e R f , NR g , O or S; R a to R g may each independently be a substituted or unsubstituted alkyl group having 1 to 15 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring; R a and R b , R c and R d , and / or R e and R f may combine with each other to form a ring; and A1 may be represented by one of Formula D-2-3 to Formula D-2-10:

[0036]

[0037] Y2 can be C═O or S(═O)2; Y3 can be C═O or O; Y4 and Y5 can each independently be O or S; Y6 and Y7 can each independently be N or CQ 12 , Y8 can be O or NQ 13 ; Q1 to Q 13 can each independently be an alkyl group having 1 to 15 carbon atoms which is substituted or unsubstituted, an aryl group having 6 to 30 carbon atoms for forming a ring which is substituted or unsubstituted, or a heteroaryl group having 2 to 30 carbon atoms for forming a ring which is substituted or unsubstituted; n1, n4 and n6 can each independently be an integer selected from 0 to 4; n3, n5, n7, n8 and n10 can each independently be an integer selected from 0 to 3; n2 can be an integer selected from 0 to 5; n9 can be an integer selected from 0 to 2, and refers to the connection position.

[0038] In an embodiment, the first body and the second body can be in a weight ratio of about 7:3 to about 3:7.

[0039] In an embodiment, based on the total weight of the first body, the second body, the first dopant and the second dopant, the amount of the first dopant can be about 10 wt% to about 15 wt%, and the amount of the second dopant can be about 1 wt% to about 5 wt%.

[0040] One or more example embodiments of the present disclosure provide an organic electroluminescent device, which includes: a first electrode; a second electrode on the first electrode; and an emission layer between the first electrode and the second electrode. The emission layer includes: a first body; a second body different from the first body; a first dopant having a second initial wavelength; and a second dopant different from the first dopant and having a third initial wavelength. The third initial wavelength can be greater than the second initial wavelength, and the normalized light intensity at the intersection of the normalized light absorption spectrum and the normalized light emission spectrum of the second dopant can be about 0.5 or greater.

[0041] One or more example embodiments of the present disclosure provide an organic electroluminescent device, which includes: a first electrode; a second electrode on the first electrode; and an emission layer between the first electrode and the second electrode. The emission layer includes: a first host, which includes a hole transport portion; a second host, which is different from the first host and includes an electron transport portion; a first dopant, which has a second starting wavelength and includes an organometallic complex containing Ir, Ru, Rh, Pt, Pd, Cu, or Os as a central metal element; and a second dopant, which has a third starting wavelength and is a delayed fluorescence emitter. The third starting wavelength may be greater than the second starting wavelength. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate example embodiments of the present disclosure and, together with the description, are used to explain the principles of the present disclosure. In the drawings:

[0043] Figure 1 is a schematic cross-sectional view of an organic electroluminescent device according to an embodiment of the present disclosure;

[0044] Figure 2 is a schematic cross-sectional view of an organic electroluminescent device according to an embodiment of the present disclosure;

[0045] Figure 3 is a schematic cross-sectional view of an organic electroluminescent device according to an embodiment of the present disclosure;

[0046] Figure 4 is a schematic cross-sectional view of an organic electroluminescent device according to an embodiment of the present disclosure;

[0047] Figure 5 is a schematic cross-sectional view of an organic electroluminescent device according to an embodiment of the present disclosure;

[0048] Figures 6A to 6F is a graph of the normalized emission spectra (intensity versus wavelength) of the host, the first dopant, and the second dopant according to an example embodiment of the present disclosure; and

[0049] Figure 7A and Figure 7B is a graph of the light emission spectrum and the light absorption spectrum (intensity versus wavelength) of the second dopant according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0050] The present disclosure may have various modifications and may be embodied in different forms, and exemplary embodiments will be explained in more detail with reference to the accompanying drawings. However, the present disclosure may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. On the contrary, all modifications, equivalents, and substitutions included within the spirit and scope of the present disclosure should be included in the present disclosure.

[0051] It will be understood that when an element (or region, layer, component, etc.) is referred to as being "on," "connected to," or "coupled to" another element, it may be directly on, directly connected to, or directly coupled to the other element, or a third intermediate element may be present.

[0052] Like reference numerals refer to like elements throughout, and a repeated description thereof may not be provided. Additionally, in the drawings, the thickness, ratios, and dimensions of the constituent elements may be enlarged for effective explanation of the technical content.

[0053] The term "and / or" includes one or more combinations that may be defined by the related elements. As used herein, the terms "substantially," "about," and similar terms are used as approximate terms and not as terms of degree, and are intended to account for the inherent deviations of measured or calculated values that would be recognized by a person of ordinary skill in the art.

[0054] It will be understood that although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, without departing from the teachings of the present disclosure, a first element may be referred to as a second element. Similarly, a second element may be referred to as a first element. As used herein, the singular form is also intended to include the plural form unless the context clearly indicates otherwise.

[0055] Additionally, the terms "beneath," "below," "above," and "on" are used to explain the relationship of elements shown in the drawings. The terms are relative concepts and are to be interpreted based on the directions shown in the drawings.

[0056] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by a person of ordinary skill in the art to which the present disclosure pertains. It will be further understood that terms, such as those defined in a commonly used dictionary, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0057] It will be further understood that when the terms "includes", "including", "comprises" and / or "comprising" are used in this specification, they indicate the presence of the stated features, numbers, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, elements, components, or combinations thereof.

[0058] Hereinafter, an organic electroluminescent device according to an embodiment of the present disclosure will be explained with reference to the accompanying drawings.

[0059] Figures 1 to 5 FIG. is a schematic cross-sectional view of an organic electroluminescent device according to an exemplary embodiment of the present disclosure. Refer to Figures 1 to 5 , in the organic electroluminescent device 10 of the embodiment, a first electrode EL1 and a second electrode EL2 are oppositely disposed, and an emission layer EML may be disposed between the first electrode EL1 and the second electrode EL2.

[0060] In addition, in addition to the emission layer EML, the organic electroluminescent device 10 of the embodiment may further include a plurality of functional layers between the first electrode EL1 and the second electrode EL2. The plurality of functional layers may include a hole transport region HTR and an electron transport region ETR. For example, the organic electroluminescent device 10 according to an embodiment may include a first electrode EL1, a hole transport region HTR, an emission layer EML, an electron transport region ETR, and a second electrode EL2, which are stacked in this stated order. In some embodiments, the organic electroluminescent device 10 of the embodiment may include a capping layer CPL disposed on the second electrode EL2.

[0061] The organic electroluminescent device 10 of the embodiment may include a compound of the embodiment to be explained later in the emission layer EML disposed between the first electrode EL1 and the second electrode EL2. However, the embodiments of the present disclosure are not limited thereto, and in some embodiments, the organic electroluminescent device 10 of the embodiment may include a compound of the embodiment to be explained later in the hole transport region HTR or the electron transport region ETR (the hole transport region HTR or the electron transport region ETR is included in the plurality of functional layers disposed between the first electrode EL1 and the second electrode EL2 in addition to the emission layer EML), or in the capping layer CPL disposed on the second electrode EL2.

[0062] Figure 2 FIG. shows a cross-sectional view of the organic electroluminescent device 10 of the embodiment, wherein 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. Figure 3A cross-sectional view of the organic electroluminescent device 10 of an embodiment is shown, wherein 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 A cross-sectional view of the organic electroluminescent device 10 of an embodiment including a buffer layer BFL between the emission layer EML and the electron transport region ETR is shown. Figure 5 A cross-sectional view of the organic electroluminescent device 10 of an embodiment including a capping layer CPL disposed on the second electrode EL2 is shown.

[0063] The first electrode EL1 has conductivity (e.g., may be conductive). The first electrode EL1 can be formed using a metal alloy or a conductive compound. The first electrode EL1 can be an anode. In some embodiments, the first electrode EL1 can be a pixel electrode. The first electrode EL1 can be a transmissive electrode, a transmissive-reflective electrode, or a reflective electrode. If the first electrode EL1 is a transmissive electrode, the first electrode EL1 can include a transparent metal oxide (such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), and / or indium tin zinc oxide (ITZO)). If the first electrode EL1 is a transmissive-reflective electrode or a reflective electrode, the first electrode EL1 can include silver (Ag), magnesium (Mg), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), LiF / Ca, LiF / Al, molybdenum (Mo), titanium (Ti), their compounds, or their mixtures (e.g., a mixture of Ag and Mg). In some embodiments, the first electrode EL1 can have a structure including multiple layers, the multiple layers including a reflective layer or a transmissive-reflective layer formed using the above materials, and a transmissive conductive layer formed using ITO, IZO, ZnO, or ITZO. For example, the first electrode EL1 can include a three-layer structure of ITO / Ag / ITO. However, the embodiments of the present disclosure are not limited thereto. The thickness of the first electrode EL1 can be about to about For example, about to about

[0064] The hole transport region HTR is provided on the first electrode EL1. The hole transport region HTR can include at least one of a hole injection layer HIL, a hole transport layer HTL, a hole buffer layer, and an electron blocking layer EBL. The thickness of the hole transport region HTR can be about to about

[0065] The hole transport region HTR may have a single layer formed of a single material, a single layer formed of multiple different materials, or a multi-layer structure including multiple layers formed of multiple different materials.

[0066] For example, the hole transport region HTR may have a single-layer structure including a hole injection layer HIL or a hole transport layer HTL, or may have a single-layer structure including a hole injection material and a hole transport material (e.g., synchronously included or as a mixture). In some embodiments, the hole transport region HTR may have a structure of multiple layers formed of multiple different materials, such as a structure including a hole injection layer HIL / hole transport layer HTL, a hole injection layer HIL / hole transport layer HTL / hole buffer layer, a hole injection layer HIL / hole buffer layer, a hole transport layer HTL / hole buffer layer, or a hole injection layer HIL / hole transport layer HTL / electron blocking layer EBL, each stacked on the first electrode EL1, without limitation.

[0067] The hole transport region HTR can be formed using various suitable methods, such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) method, inkjet printing, laser printing, and / or laser-induced thermal imaging (LITI) method.

[0068] The hole injection layer HIL may include, for example, phthalocyanine compounds (such as copper phthalocyanine), N,N′-diphenyl-N,N′-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-phenyl-4,4′-diamine (DNTPD), 4,4′,4″-[tris(3-methylphenyl)phenylamino]triphenylamine (m-MTDATA), 4,4′,4″-tris(N,N-diphenylamino)triphenylamine (TDATA), 4,4′,4″-tris{N-(2-naphthyl)-N-phenylamino}-triphenylamine (2-TNATA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), polyaniline / camphorsulfonic acid (PANI / CSA), polyaniline / poly(4-styrenesulfonate) (PANI / PSS), N,N′-di(1-naphthalen-1-yl)-N,N′-diphenyl-benzidine (NPB), triphenylamine-containing polyether ketone (TPAPEK), 4-isopropyl-4′-methyldiphenyliodonium [tetrakis(pentafluorophenyl)borate], and / or dipyrazino[2,3-f:2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN).

[0069] The hole transport layer (HTL) may include, for example, carbazole derivatives (such as N-phenylcarbazole and polyvinylcarbazole), fluorine derivatives, N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1-biphenyl]-4,4′-diamine (TPD), triphenylamine derivatives (such as 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA)), N,N′-di(1-naphthalen-1-yl)-N,N′-diphenyl-benzidine (NPB), 4,4′-cyclohexylidenebis[N,N-bis(4-methylphenyl)aniline] (TAPC), 4,4′-bis[N,N′-(3-tolyl)amino]-3,3′-dimethylbiphenyl (HMTPD), 1,3-bis(N-carbazolyl)benzene (mCP), etc.

[0070] The thickness of the hole transport region (HTR) may be about to about For example, about to about The thickness of the hole injection layer (HIL) may be, for example, about to about And the thickness of the hole transport layer (HTL) may be about to about For example, the thickness of the electron blocking layer (EBL) may be about to about If the thicknesses of the hole transport region (HTR), hole injection layer (HIL), hole transport layer (HTL), and electron blocking layer (EBL) satisfy the above ranges, satisfactory hole transport properties can be achieved without a significant increase in the driving voltage.

[0071] In addition to the above materials, the hole transport region (HTR) may further include a charge generation material to increase conductivity. The charge generation material may be dispersed in the hole transport region (HTR) substantially uniformly or non-uniformly. The charge generation material may be, for example, a p-dopant. The p-dopant may be a quinone derivative, a metal oxide, or a cyanide-containing compound, without limitation. For example, non-limiting examples of the p-dopant include quinone derivatives (such as tetracyanoquinodimethane (TCNQ) and / or 2,3,5,6-tetrafluoro-7,7′,8,8′-tetracyanoquinodimethane (F4-TCNQ)), metal oxides (such as tungsten oxide and / or molybdenum oxide), and inorganic metal compounds (such as CuI and / or RbI), without limitation.

[0072] As described above, in addition to the hole injection layer HIL and the hole transport layer HTL, the hole transport region HTR may further include at least one of a hole buffer layer and an electron blocking layer EBL. The hole buffer layer may compensate for the optical resonance distance according to the wavelength of the light emitted from the emission layer EML, and thus may increase the light emission efficiency. The hole transport region HTR and the hole buffer layer may include the same material. The electron blocking layer EBL may prevent or reduce the injection of electrons from the electron transport region ETR into the hole transport region HTR.

[0073] The emission layer EML is provided on the hole transport region HTR. The emission layer EML may have, for example, a thickness of about to about or about to about . The emission layer EML may have a single layer formed of a single material, a single layer formed of a plurality of different materials, or a multilayer structure having a plurality of layers formed of a plurality of different materials.

[0074] In the organic electroluminescent device 10 of the embodiment, the emission layer EML may include a plurality of different types (e.g., categories) of light-emitting materials. The organic electroluminescent device 10 of the embodiment may include a first host and a second host different from each other, and a first dopant and a second dopant different from each other.

[0075] In the present description, the term "substituted or unsubstituted" refers to a state of being substituted or unsubstituted by at least one substituent selected from the group consisting of: a deuterium atom, a halogen atom, a cyano group, a nitro group, an amino group, a silyl group, an oxy group, a thio group, a sulfinyl group, a sulfonyl group, a carbonyl group, a boron group, a phosphinyl oxide group, a phosphinyl sulfide group, an alkyl group, an alkenyl group, an alkoxy group, a hydrocarbon ring group, an aryl group, and a heterocyclic group. Each of the exemplary substituents may further be substituted or unsubstituted. For example, in some embodiments, a biphenyl group may be interpreted as the named aryl group, or in some embodiments, it may be interpreted as a phenyl group substituted by a phenyl group.

[0076] In the present description, the term "forming a ring by combining with an adjacent group" may refer to forming a substituted or unsubstituted hydrocarbon ring or heterocyclic ring by combining with an adjacent group. The term "hydrocarbon ring" includes an aliphatic hydrocarbon ring and an aromatic hydrocarbon ring. The term "heterocyclic ring" includes an aliphatic heterocyclic ring and an aromatic heterocyclic ring. The ring formed by combining with an adjacent group may be a monocyclic or polycyclic ring. Additionally, the ring formed by combining with an adjacent group may further combine with another ring to form a spiro structure.

[0077] In this description, the term "adjacent group" may refer to substituents on adjacent bonded atoms, substituents on the same atom, or substituents that are spatially in the closest position to the corresponding substituent (e.g., within the bonding distance of the corresponding substituent). For example, in 1,2-dimethylbenzene, the two methyl groups can be interpreted as "adjacent groups" to each other, and in 1,1-diethylcyclopentene, the two ethyl groups can be interpreted as "adjacent groups" to each other.

[0078] In this description, non-limiting examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, or iodine atoms.

[0079] In this description, the term "alkyl" may refer to straight-chain, branched-chain, or cyclic alkyl groups. The number of carbons in the alkyl group can be 1 to 50, 1 to 30, 1 to 20, 1 to 15, 1 to 10, or 1 to 6. Non-limiting examples of alkyl groups can include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, 2-ethylbutyl, 3,3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, cyclopentyl, 1-methylpentyl, 3-methylpentyl, 2-ethylpentyl, 4-methyl-2-pentyl, n-hexyl, 1-methylhexyl, 2-ethylhexyl, 2-butylhexyl, cyclohexyl, 4-methylcyclohexyl, 4-tert-butylcyclohexyl, n-heptyl, 1-methylheptyl, 2,2-dimethylheptyl, 2-ethylheptyl, 2-butylheptyl, n-octyl, tert-octyl, 2-ethyloctyl, 2-butyl octyl, 2-hexyloctyl, 3,7-dimethyloctyl, cyclooctyl, n-nonyl, n-decyl, adamantyl, 2-ethyldecyl, 2-butyldecyl, 2-hexyldecyl, 2-octyldecyl, n-undecyl, n-dodecyl, 2-ethyldodecyl, 2-butyldodecyl, 2-hexyldodecyl, 2-octyldodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, 2-ethylhexadecyl, 2-butyldecyl, 2-hexyldecyl, 2-octyldecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, 2-ethyleicosyl, 2-butyldecyl, 2-hexyldecyl, 2-octyldecyl, n-heneicosyl, n-docosyl, n-tricosyl, n-tetracosyl, n-pentacosyl, n-hexacosyl, n-heptacosyl, n-octacosyl, n-nonacosyl, n-triacontyl, etc.

[0080] In this description, the term "alkenyl" refers to a hydrocarbon group that includes one or more carbon-carbon double bonds at the middle and / or end of an alkyl group containing 2 or more carbon atoms. The alkenyl group can be straight-chain or branched-chain. There is no specific limit on the number of carbons in the alkenyl group, but it can be 2 to 30, 2 to 20, or 2 to 10. Non-limiting examples of alkenyl groups include vinyl, 1-butenyl, 1-pentenyl, 1,3-butadienyl aryl, styryl, styryl vinyl, etc.

[0081] In this description, the term "alkynyl" refers to a hydrocarbon group that includes one or more carbon-carbon triple bonds at the middle or end of an alkyl group having 2 or more carbon atoms. The alkynyl group can be straight-chain or branched-chain. There is no specific limitation on the number of carbons in the alkynyl group, but it can be 2 to 30, 2 to 20, or 2 to 10. Non-limiting examples of the alkynyl group include ethynyl, propynyl, and the like.

[0082] In this description, the term "hydrocarbon ring group" may refer to an optional functional group or substituent derived from an aliphatic hydrocarbon ring, or an optional functional group or substituent derived from an aromatic hydrocarbon ring. The number of carbons in the hydrocarbon ring can be 5 to 60, 5 to 30, or 5 to 20.

[0083] In this description, the term "aryl" refers to an optional functional group or substituent derived from an aromatic hydrocarbon ring. The aryl group can be a monocyclic aryl group or a polycyclic aryl group. The number of carbons in the ring of the aryl group can be 6 to 30, 6 to 20, or 6 to 15. Non-limiting examples of the aryl group can include phenyl, naphthyl, fluorenyl, anthracenyl, phenanthryl, biphenyl, terphenyl, quaterphenyl, quinquephenyl, sexiphenyl, benzo[9,10]phenanthryl, pyrenyl, benzofluoranthenyl, chrysenyl, and the like.

[0084] In this description, the term "heterocyclic group" refers to an optional functional group or substituent derived from a ring including one or more heteroatoms selected from boron (B), oxygen (O), nitrogen (N), phosphorus (P), silicon (Si), and sulfur (S). The heterocyclic group can be an aliphatic heterocyclic group or an aromatic heterocyclic group. The aromatic heterocyclic group can be a heteroaryl group. The aliphatic heterocycle and the aromatic heterocycle can each be monocyclic or polycyclic.

[0085] In this description, the heterocyclic group can include one or more of B, O, N, P, Si, and S as heteroatoms. If the heterocyclic group includes two or more heteroatoms, the two or more heteroatoms can be the same or different. The heterocyclic group can be a monocyclic heterocyclic group or a polycyclic heterocyclic group, and in some embodiments, can include a heteroaryl group. The number of carbons in the ring of the heterocyclic group can be 2 to 30, 2 to 20, or 2 to 10.

[0086] In this description, the aliphatic heterocyclic group can include one or more of B, O, N, P, Si, and S as heteroatoms. The number of carbons in the ring of the aliphatic heterocyclic group can be 2 to 30, 2 to 20, or 2 to 10. Non-limiting examples of the aliphatic heterocyclic group include oxiranyl, thiiranyl, pyrrolidinyl, piperidinyl, tetrahydrofuranyl, tetrahydrothienyl, thianyl, tetrahydropyranyl, 1,4-dioxanyl, and the like.

[0087] In this description, a heteroaryl may include one or more selected from B, O, N, P, Si, and S as heteroatoms. If a heteroaryl includes two or more heteroatoms, the two or more heteroatoms may be the same or different. A heteroaryl may be a monocyclic heterocyclic group or a polycyclic heterocyclic group. The number of carbons in the ring of the heteroaryl may be 2 to 30, 2 to 20, or 2 to 10. Non-limiting examples of heteroaryls include thienyl, furyl, pyrrolyl, imidazolyl, triazolyl, pyridyl, bipyridyl, pyrimidinyl, triazinyl, acridinyl, pyridazinyl, pyrazinyl, quinolinyl, quinazolinyl, quinoxalinyl, phenoxazinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolinyl, indolyl, carbazolyl, N-arylcarbazolyl, N-heteroarylcarbazolyl, N-alkylcarbazolyl, benzoxazolyl, benzimidazolyl, benzothiazolyl, benzocarbazolyl, benzothienyl, dibenzothienyl, thienothienyl, benzofuryl, phenanthrolinyl, thiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, thiadiazolyl, phenothiazinyl, dibenzosilolyl, dibenzofuryl, etc.

[0088] In this description, an arylene may be similar to an aryl, except that an arylene is a divalent group. A heteroarylene may be similar to a heteroaryl, except that a heteroarylene is a divalent group.

[0089] In this description, the term "silyl" refers to an alkylsilyl or an arylsilyl. Non-limiting examples of silyls include trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, vinyldimethylsilyl, propyldimethylsilyl, triphenylsilyl, diphenylsilyl, phenylsilyl, etc.

[0090] In this description, the term "boron group" refers to an alkylboron group or an arylboron group. Non-limiting examples of boron groups include trimethylboron, triethylboron, tert-butyldimethylboron, triphenylboron, diphenylboron, phenylboron, etc.

[0091] In this description, there is no specific limitation on the number of carbons in an amino group, but it may be 1 to 30. An amino group may refer to an alkylamino group, an arylamino group, or a heteroarylamino group. Non-limiting examples of amino groups include methylamino, dimethylamino, phenylamino, diphenylamino, naphthylamino, 9-methyl-anthrylamino, triphenylamino, etc.

[0092] In this description, the term "oxy" may refer to an alkoxy or an aryloxy. An alkoxy may include a straight-chain, branched-chain, or cyclic alkyl chain. There is no specific limitation on the number of carbons in the alkoxy, but it may be, for example, 1 to 20 or 1 to 10. Non-limiting examples of oxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, butoxy, pentyloxy, hexyloxy, octyloxy, nonyloxy, decyloxy, benzyloxy, etc.

[0093] In this description, the alkyl group in alkylthio, alkylsulfoxy, alkylaryl, alkylamino, alkylboron, and alkylsilyl is the same as described above, including examples.

[0094] In this description, the aryl group in aryloxy, arylthio, arylsulfoxy, arylamino, arylboron, arylsilyl, arylseleno, and arylalkyl is the same as described above, including examples.

[0095] In this description, the term "directly connected" may refer to a single bond.

[0096] In this description, or refers to the connection position (e.g., the connection position with another formula).

[0097] The emission layer EML of the organic electroluminescent device 10 of the 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. In some embodiments, the host may include a first host and a second host different from the first host. The host may include a first host having a hole transport portion and a second host having an electron transport portion. For example, in the emission layer EML of the organic electroluminescent device 10 of the embodiment, the host may be an exciplex formed by the first host and the second host.

[0098] The emission layer EML of the embodiment may include a first host containing a carbazolyl derivative moiety. The first host may be represented by formula H-1:

[0099] [Formula H-1]

[0100]

[0101] In formula H-1, L1 may be a directly connected, substituted or unsubstituted arylene having 6 to 30 carbon atoms for forming a ring or a substituted or unsubstituted heteroarylene having 2 to 30 carbon atoms for forming a ring. Ar1 may be a substituted or unsubstituted aryl having 6 to 30 carbon atoms for forming a ring or a substituted or unsubstituted heteroaryl having 2 to 30 carbon atoms for forming a ring.

[0102] In Formula H-1, "a" and "b" can each independently be an integer selected from 0 to 4, and R1 and R2 can each independently be a substituted or unsubstituted aryl having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroaryl having 2 to 30 ring-forming carbon atoms. When "a" and "b" are each independently an integer of 2 or greater, multiple R1 groups and multiple R2 groups can be the same, or at least one of them can be different. In some embodiments, in Formula H-1, "a" and "b" can be 0. In this case, the carbazolyl group is unsubstituted.

[0103] In Formula H-1, L1 can be a direct bond, a phenylene group, a divalent biphenyl group, a divalent carbazolyl group, etc., but the embodiments of the present disclosure are not limited thereto. Ar1 can be a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted biphenyl group, etc., but the embodiments of the present disclosure are not limited thereto.

[0104] In the organic electroluminescent device 10 of the embodiment, the emission layer EML can include a compound represented by Formula H-2 as a second host:

[0105] [Formula H-2]

[0106]

[0107] In Formula H-2, Z1 to Z3 can each independently be CR y or N, and R y and R 11 to R 13 can each independently be a hydrogen atom, a deuterium atom, a cyano group, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroaryl having 2 to 30 ring-forming carbon atoms.

[0108] For example, Formula H-2 can be represented by one of Formula H-2a and Formula H-2b:

[0109]

[0110] In Formula H-2a and Formula H-2b, R 11 to R 13 can each independently be a hydrogen atom, a deuterium atom, a cyano group, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroaryl having 2 to 30 ring-forming carbon atoms.

[0111] In addition, in Formula H-2b, R y1 to R y3Each may independently be 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 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring. Additionally, in Formula H-2b, R selected from 11 to R 13 and R y1 to R y3 at least one of which may be a cyano group, an aryl group having 6 to 30 carbon atoms for forming a ring including at least one cyano group as a substituent, or a heteroaryl group having 2 to 30 carbon atoms for forming a ring including at least one cyano group as a substituent.

[0112] For example, the second host represented by Formula H-2a may include a triazine moiety, and the second host represented by Formula H-2b may include at least one cyano group.

[0113] In Formula H-2a, R 11 to R 13 may each independently be a substituted or unsubstituted phenyl group, a substituted or unsubstituted carbazolyl group, etc., but embodiments of the present disclosure are not limited thereto.

[0114] In Formula H-2b, any one selected from R 11 to R 13 and R y1 to R y3 may be substituted with a cyano group, or at least one of R selected from 11 to R 13 and R y1 to R y3 may be a heteroaryl group having 2 to 30 carbon atoms for forming a ring substituted with a cyano group. The heteroaryl group having 2 to 30 carbon atoms for forming a ring substituted with at least one cyano group may further include substituents other than the cyano group, and the substituent may be 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 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring.

[0115] The organic electroluminescent device 10 according to an embodiment may synchronously (e.g., simultaneously) include the first host represented by Formula H-1 and the second host represented by Formula H-2 in the emission layer EML, may also include a first dopant and a second dopant (described in more detail below) in the emission layer EML, and may exhibit excellent emission efficiency and long lifetime characteristics. In the emission layer EML of the organic electroluminescent device 10 according to an embodiment, the host may be an exciplex formed by the first host represented by Formula H-1 and the second host represented by Formula H-2.

[0116] Among two host materials included in the emission layer EML in synchronization, the first host may be a hole-transporting host, and the second host may be an electron-transporting host. The organic electroluminescent device 10 of an embodiment may include both the first host having excellent hole-transporting properties and the second host having excellent electron-transporting properties in the emission layer EML (e.g., in synchronization), such that the energy transferred to the dopant compound may be effective.

[0117] The emission layer EML may include an organometallic complex as a first dopant, the organometallic complex including a central metal element such as iridium (Ir), ruthenium (Ru), rhodium (Rh), platinum (Pt), palladium (Pd), copper (Cu), or osmium (Os) bonded to one or more ligands. In the organic electroluminescent device 10 of an embodiment, the emission layer EML may include a compound represented by Formula D-1 as the first dopant:

[0118] [Formula D-1]

[0119]

[0120] In Formula D-1, M may be a metal element, such as a transition metal element. M may be Pt, Pd, Cu, Os, Ir, Ru, or Rh.

[0121] In Formula D-1, Q1 to Q4 may each independently be C or N.

[0122] In Formula D-1, C1 to C4 may each independently be a substituted or unsubstituted hydrocarbon ring having 5 to 30 carbon atoms for forming a ring or a substituted or unsubstituted heterocyclic ring having 2 to 30 carbon atoms for forming a ring.

[0123] In Formula D-1, L 21 to L 23 may each independently be a direct bond, a substituted or unsubstituted divalent alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted arylene group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroarylene group having 2 to 30 carbon atoms for forming a ring. In L 21 to L 23 means a connecting portion with C1 to C4.

[0124] In Formula D-1, e1 to e3 may each independently be 0 or 1. When e1 is 0, C1 and C2 may not be connected to each other. When e2 is 0, C2 and C3 may not be connected to each other. When e3 is 0, C3 and C4 may not be connected to each other.

[0125] R 21 to R 26 ​Each may independently be 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, or may each combine with an adjacent group to form a ring. For example, when R 21 to R 26 is an alkyl group, R 21 to R 26 may be a methyl group, an isopropyl group, or a tert-butyl group. When R 21 to R 26 is an amino group, R 21 to R 26 may be a dimethylamino group. When R 21 to R 26 is a halogen atom, R 21 to R 26 may be a fluorine atom (F).

[0126] d1 to d4 may each independently be an integer selected from 0 to 4. When d1 to d4 are each an integer of 2 or greater, the plurality of R 21 to R 24 groups may all be the same, or at least one may be different.

[0127] "m" may be 1 or 2. When M is Pt, Pd, Cu, or Os, "m" may be 1. When M is Ir, Ru, or Rh, "m" may be 1 or 2, and e2 may be 0.

[0128] For example, Formula D-1 may be represented by Formula D-1a-1:

[0129] [Formula D-1a-1]

[0130]

[0131] In Formula D-1a-1, C1 to C4, Q1 to Q4, R 21 to R 24 , d1 to d4, L 22 and e2 may be the same as those described in connection with Formula D-1 herein.

[0132] In Formula D-1a-1, C1 to C4 may each independently be a substituted or unsubstituted hydrocarbon ring or a substituted or unsubstituted heterocyclic ring represented by any one of C-1 to C-3:

[0133]

[0134] In C-1 to C-3, P1 may be or CR 54 , P2 may be or NR61 , and P3 can be or NR 62 . R 51 to R 64 can each independently be 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, or can each combine with an adjacent group to form a ring.

[0135] Additionally, among C-1 to C-3, refers to the connection point with M (central metal atom), and refers to the connection point with an adjacent ring group (C1 to C4) or a linker (L 21 to L 24 ).

[0136] For example, Formula D-1 can be represented by Formula D-1b-1:

[0137] [Formula D-1b-1]

[0138]

[0139] In Formula D-1b-1, X1 to X4, Y1 to Y4, and Z1 to Z4 can each independently be CR n or N. Additionally, R p , R q and R n can each independently be 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 having 5 to 30 ring-forming carbon atoms, a substituted or unsubstituted heterocyclic ring having 2 to 30 ring-forming carbon atoms, or a substituted or unsubstituted amino group, or can each combine with an adjacent group to form a ring. In Formula D-1b-1, the hexagonal rings including X1 to X4, Y1 to Y4, or Z1 to Z4 as ring-forming atoms can each independently be 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.

[0140] The first dopant represented by Formula D-1a-1 or Formula D-1b-1 can be a phosphorescent dopant.

[0141] In addition to the first dopant represented by Formula D-1, the organic electroluminescent device 10 of the embodiment can include a second dopant in the emission layer EML. The second dopant can be a fluorescent dopant. The second dopant can be a material that emits blue light.

[0142] In the organic electroluminescent device 10 of the embodiment, the emission layer EML may include a compound represented by one of Formula D-2a and Formula D-2b as a second dopant:

[0143] [Formula D-2a]

[0144]

[0145] In Formula D-2a, X1 and X2 may each independently be NR m or O, and R m may be 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 Formula D-2a, R 31 to R 41 may each independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted boron 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, or may each combine with an adjacent group to form a ring.

[0146] For example, in Formula D-2a, R 31 to R 41 may each independently be 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 alkylboron group, or a substituted or unsubstituted arylboron group.

[0147] In Formula D-2a, R 39 and R 40 may combine with each other to form a heterocycle. The fused heterocycle formed by combining R 39 and R 40 with each other may include B, O, or N as a heteroatom. The fused heterocycle may be unsubstituted, or substituted with a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group.

[0148] The second dopant represented by Formula D-2a may be represented by any one of Formula D-2a-1 to Formula D-2a-4:

[0149]

[0150] In Formula D-2a-1 to Formula D-2a-4, R m1 to R m4Each may independently be 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 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring. R1 to R 18 Each may independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted boron 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 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, or each may combine with an adjacent group to form a ring.

[0151] For example, R m1 to R m4 Each may independently be a hydrogen atom or a substituted or unsubstituted phenyl group. Additionally, R1 to R 18 Each may 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 carbon atoms for forming a ring. However, the embodiments of the present disclosure are not limited thereto.

[0152] [Formula D-2b]

[0153] D1-L2-A1.

[0154] In Formula D-2b, L2 may be a direct bond, a substituted or unsubstituted arylene group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroarylene group having 2 to 30 carbon atoms for forming a ring. For example, L2 may be a direct bond or a substituted or unsubstituted phenylene group.

[0155] In Formula D-2b, D1 may be represented by one of Formula D-2-1 and Formula D-2-2:

[0156]

[0157] In Formula D-2-1 and Formula D-2-2, L3 and L4 may each independently be a direct bond or a substituted or unsubstituted arylene group having 6 to 30 carbon atoms for forming a ring. For example, L3 and L4 may each independently be a direct bond or a substituted or unsubstituted phenylene group.

[0158] R 42 to R 59Each may independently be 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 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring. In some embodiments, R 42 to R 59 may each combine with an adjacent group to form a ring.

[0159] Y1 may be a direct bond, CR a R b , SiR c R d , GeR e R f , NR g , O, or S. In an embodiment, Y1 may be a direct bond, CR a R b , NR g , or O.

[0160] R a to R g may each independently be a substituted or unsubstituted alkyl group having 1 to 15 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring. R a and R b , R c and R d as well as R e and R f in each pair may combine with each other to form a ring.

[0161] In formula D-2b, A1 may be represented by one of formula D-2-3 to formula D-2-10:

[0162]

[0163] In formula D-2-3, Y2 may be C═O or S(C═O)2. In formula D-2-4, Y3 may be C═O or O. In formula D-2-5, Y4 and Y5 may each independently be O or S. In formula D-2-8, Y6 and Y7 may each independently be N or CQ 12 . In formula D-2-10, Y8 may be O or NQ 13 .

[0164] In formula D-2-3 to formula D-2-10, Q1 to Q 13Each may independently be 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.

[0165] In Formulae D-2-3 to D-2-10, n1, n4, and n6 may each independently be an integer selected from 0 to 4; n3, n5, n7, n8, and n10 may each independently be an integer selected from 0 to 3; n2 may be an integer selected from 0 to 5; and n9 may be an integer selected from 0 to 2. When n1 to n10 are each independently an integer of 2 or greater, multiple Q1 to Q 10 may be the same, or at least one may be different.

[0166] The organic electroluminescent device 10 of an embodiment may include a first dopant represented by Formula D-1 and a second dopant represented by Formula D-2a or Formula D-2b in the emission layer EML. For example, the organic electroluminescent device 10 of an embodiment may include the first dopant and the second dopant synchronously (e.g., together) and may exhibit excellent emission efficiency and / or improved device lifetime characteristics.

[0167] The lowest triplet excitation energy level (T1 level) of the first dopant may be substantially equal to or greater than the lowest triplet excitation energy level (T1 level) of the second dopant. The lowest triplet excitation energy level of the host may be substantially equal to or greater than the lowest triplet excitation energy level of the second dopant. In an embodiment, the first dopant may act as a co-dopant that transfers the energy of the host to the second dopant. The second dopant may be a luminescent dopant that is excited by the energy transferred from the host through the first dopant and then emits light. In an embodiment, the lowest triplet excitation energy level of the host may be substantially equal to or greater than the lowest triplet excitation energy levels of the first dopant and the second dopant, and the lowest triplet excitation energy level of the second dopant may be less than the lowest triplet excitation energy levels of the host and the first dopant, respectively. In this description, the lowest triplet excitation energy level (T1 level) is calculated as follows: measuring the low-temperature emission spectrum of a single film, obtaining the starting wavelength, and converting it to an energy level.

[0168] In an embodiment, the second dopant may be a thermally activated delayed fluorescence (TADF) dopant. For example, in an embodiment, the second dopant may have an inverse intersystem crossing constant (k 3 s -1 ) of about 10 RISC or greater and / or an f (vibrational intensity) of about 0.1 or greater, and thus, thermally activated delayed fluorescence can be easily generated.

[0169] In an embodiment, the second dopant is a light-emitting dopant that emits blue light, and the emission layer EML can be used to emit fluorescence. For example, the emission layer EML can emit blue light as delayed fluorescence.

[0170] In an embodiment, the first dopant (which is a co-dopant) can accelerate the delayed fluorescence of the second dopant. Accordingly, the emission efficiency of the emission layer EML of the embodiment can be improved. Additionally, when the delayed fluorescence is accelerated, excitons formed in the emission layer EML may not accumulate in the emission layer EML, but can emit light quickly, thereby reducing device degradation. Accordingly, the lifespan of the organic electroluminescent device 10 of the embodiment can be increased.

[0171] In the organic electroluminescent device 10 of the embodiment, the emission layer EML can include all of the first host, the second host, the first dopant, and the second dopant, and based on the total weight of the first host, the second host, the first dopant, and the second dopant, the amount of the first dopant can be about 10 wt% to about 15 wt%, and the amount of the second dopant can be about 1 wt% to about 5 wt%.

[0172] If the amounts of the first dopant and the second dopant satisfy the above ratio, the first dopant can effectively transfer energy to the second dopant, and accordingly, the emission efficiency and the device lifespan can be increased.

[0173] In the emission layer EML, the amounts of the first host and the second host can be, for example, the remainder excluding the total weight of the first dopant and the second dopant. For example, in the emission layer EML, based on the total weight of the first host, the second host, the first dopant, and the second dopant, the amounts of the first host and the second host can be about 80 wt% to about 89 wt%. In the total weight of the first host and the second host, the weight ratio of the first host to the second host can be about 7:3 to about 3:7.

[0174] When the amounts of the first host and the second host satisfy the above ratio, the charge balance property in the emission layer EML can be improved, and the emission efficiency and / or the device lifespan can be increased. When the amounts of the first host and the second host deviate from the above ratio range, the charge balance in the emission layer EML can be disrupted, the emission efficiency can be reduced, and the device can be easily degraded.

[0175] If the first host, the second host, the first dopant, and the second dopant included in the emission layer EML satisfy the above amounts and ratios, excellent emission efficiency and / or long lifespan can be achieved.

[0176] The organic electroluminescent device 10 of the embodiment may include all of the first host, the second host, the first dopant, and the second dopant, and the emission layer EML may include a combination of two host materials and two dopant materials. In the organic electroluminescent device 10 of the embodiment, the emission layer EML may include two different hosts, a first dopant including an organometallic complex, and a second dopant emitting delayed fluorescence, and thus may exhibit excellent emission efficiency and / or lifetime characteristics.

[0177] In an embodiment, the first host represented by Formula H-1 may be represented by any one of the compounds represented in Compound Group 1. The emission layer EML may include at least one of the compounds represented in Compound Group 1 as the first host material.

[0178] [Compound Group 1]

[0179]

[0180]

[0181] In an embodiment, the second host represented by Formula H-2 may be represented by any one of the compounds represented in Compound Group 2-1 and Compound Group 2-2. The emission layer EML may include at least one of the compounds represented in Compound Group 2-1 and Compound Group 2-2 as the second host material. Compound Group 2-1 may correspond to the second host material represented by Formula H-2a, and Compound Group 2-2 may correspond to the second host material represented by Formula H-2b.

[0182] [Compound Group 2-1]

[0183]

[0184]

[0185] [Compound Group 2-2]

[0186]

[0187]

[0188] In an embodiment, the emission layer EML may include at least one of the compounds represented in Compound Group 3-1 and Compound Group 3-2 as the first dopant material. Compound Group 3-1 may correspond to the first dopant material represented by Formula D-1a-1, and Compound Group 3-2 may correspond to the first dopant material represented by Formula D-1b-1.

[0189] [Compound Group 3-1]

[0190]

[0191]

[0192]

[0193] [Compound Group 3-2]

[0194]

[0195]

[0196] In Compound Group 3-2, among AD2-1 to AD2-4, AD2-13 to AD2-16, and AD2-25 to AD2-28, each R can independently be a hydrogen atom, a methyl group, an isopropyl group, a tert-butyl group, or a dimethylamino group.

[0197] In an embodiment, the second dopant represented by Formula D-2a or Formula D-2b can be represented by any one of the compounds represented in Compound Group 4-1 and Compound Group 4-2. The emission layer EML can include at least one compound represented in Compound Group 4-1 or Compound Group 4-2 as the second dopant material. Compound Group 4-1 can correspond to the second dopant material represented by Formula D-2a, and Compound Group 4-2 can correspond to the second dopant material represented by Formula D-2b.

[0198] [Compound Group 4-1]

[0199]

[0200]

[0201] [Compound Group 4-2]

[0202]

[0203]

[0204] In the organic electroluminescent device 10 of the 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 each of the first emission start wavelength and the second emission start wavelength. For example, the third emission start wavelength of the second dopant can be greater than the second emission start wavelength of the first dopant, and the second emission start wavelength of the first dopant can be greater than the first emission start wavelength of the host.

[0205] In this description, the term "luminescence start wavelength" is defined as the wavelength at the x-intercept value of the tangent drawn at the position where the light intensity y-value is about 0.5 in the normalized light emission spectrum (e.g., on the left side of the peak). In this description, the normalized light absorption / emission spectrum is obtained by dissolving the luminescent material in an organic solvent and dividing it by the maximum value of the first peak after measuring the absorption / emission spectrum.

[0206] Figures 6A to 6F It is a graph of the normalized light emission spectra (intensity versus wavelength) of the host, the first dopant, and the second dopant according to an embodiment of the present disclosure.

[0207] In Figures 6A to 6F it, the x-intercept value of the tangent drawn at the position where the light intensity is about 0.5 in the normalized light emission spectrum of the host can be defined as the first luminescence start wavelength (x1). In Figures 6A to 6F it, the x-intercept value of the tangent drawn at the position where the light intensity is about 0.5 in the normalized light emission spectrum of the first dopant can be defined as the second luminescence start wavelength (x2). In Figures 6A to 6F it, the x-intercept value of the tangent drawn at the position where the light intensity is about 0.5 in the normalized light emission spectrum of the second dopant can be defined as the third luminescence start wavelength (x3).

[0208] Referring to Figures 6A to 6F , according to an embodiment of the present disclosure, the third luminescence start wavelength (x3) of the second dopant has a greater value than each of the first luminescence start wavelength (x1) of the host and the second luminescence start wavelength (x2) of the first dopant. In an embodiment of the present disclosure, the first luminescence start wavelength (x1) can be less than each of the second luminescence start wavelength (x2) and the third luminescence start wavelength (x3), and the second luminescence start wavelength (x2) can have a greater value than the first luminescence start wavelength (x1) and a smaller value than the third luminescence start wavelength (x3). For example, in the emission layer EML according to an embodiment of the present disclosure, these values can increase in the order of the first luminescence start wavelength (x1), the second luminescence start wavelength (x2), and the third luminescence start wavelength (x3).

[0209] As Figure 6A shows, when the light emission peak wavelength of the host is the smallest, the light emission peak wavelength of the first dopant is greater than the light emission peak wavelength of the host, and the light emission peak wavelength of the second dopant is the largest, these values can increase in the order of the first luminescence start wavelength (x1), the second luminescence start wavelength (x2), and the third luminescence start wavelength (x3). Differently, as Figure 6BAs shown in [reference], when the peak emission wavelength of the host is the smallest and the peak emission wavelength of the first dopant is the largest, these values can also increase in the order of the first emission start wavelength (x1), the second emission start wavelength (x2), and the third emission start wavelength (x3). As Figure 6C As shown in [reference], when the peak emission wavelength of the host is greater than the peak emission wavelength of the first dopant and the peak emission wavelength of the second dopant has the maximum value, these values can also increase in the order of the first emission start wavelength (x1), the second emission start wavelength (x2), and the third emission start wavelength (x3). As Figure 6D As shown in [reference], when the peak emission wavelength of the second dopant is the smallest and the peak emission wavelength of the first dopant is the largest, these values can also increase in the order of the first emission start wavelength (x1), the second emission start wavelength (x2), and the third emission start wavelength (x3). As Figure 6E As shown in [reference], when the peak emission wavelength of the host is the largest and the peak emission wavelength of the first dopant is the smallest, these values can also increase in the order of the first emission start wavelength (x1), the second emission start wavelength (x2), and the third emission start wavelength (x3). As Figure 6F As shown in [reference], when the peak emission wavelength of the second dopant is the smallest, the peak emission wavelength of the host is the largest, and the wavelengths are similar at the positions where the light intensities of the normalized emission spectra of the host, the first dopant, and the second dopant are all about 0.5 (for example, when the x-values corresponding to the y-value of 0.5 in each of the normalized emission spectra of the host, the first dopant, and the second dopant are similar), these values can also increase in the order of the first emission start wavelength (x1), the second emission start wavelength (x2), and the third emission start wavelength (x3).

[0210] In an embodiment of the present disclosure, the first emission start wavelength can be from about 380 nm to about 430 nm, the second emission start wavelength can be from about 400 nm to about 450 nm, and the third emission start wavelength can be from about 410 nm to about 460 nm.

[0211] In an embodiment of the present disclosure, the emission start wavelength and the emission start energy are inversely proportional to each other and can satisfy Equation 1:

[0212] [Equation 1]

[0213] Emission start energy of the host > Emission start energy of the first dopant > Emission start energy of the second dopant

[0214] Meanwhile, in this description, the start energy is a concept inversely proportional to the start wavelength and is obtained by dividing the absolute value of the photon energy by the start wavelength.

[0215] In the organic electroluminescent device 10 according to an embodiment of the present disclosure, the emission 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 greater value than each of the first emission start wavelength and the second emission start wavelength. For example, the third emission start wavelength is greater than the second emission start wavelength, and the second emission start wavelength may be greater than the first emission start wavelength.

[0216] In the organic electroluminescent device 10 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 (which acts as a co-dopant) is less than the emission start wavelength of the second dopant, and the emission start wavelength of the host has the minimum value. Therefore, energy transfer from the host to the first dopant and from the first dopant to the second dopant can be easily achieved, and thus, the organic electroluminescent device 10 can exhibit excellent emission efficiency and / or lifetime characteristics.

[0217] Figure 7A and Figure 7B is a graph of the light emission spectrum and the light absorption spectrum (intensity versus wavelength) of the second dopant according to an embodiment of the present disclosure.

[0218] Reference Figure 7A and Figure 7B , in the organic electroluminescent device 10 according to an embodiment, the normalized light intensity at the intersection point (c or c') of the normalized light absorption spectrum and the normalized light emission spectrum of the second dopant may be about 0.5 or greater. Additionally, in the organic electroluminescent device 10 according to an embodiment, the distance (n or n') between the peak of the normalized light absorption spectrum and the peak of the normalized light emission spectrum of the second dopant may be about 50 nm or less. For example, the peak-to-peak distance n or n' between the light absorption peak and the light emission peak in the normalized spectrum may be about 50 nm or less. When the above conditions of the light absorption spectrum and the light emission spectrum of the second dopant are satisfied, energy transfer from the host and the first dopant to the second dopant can be easily achieved. Therefore, the organic electroluminescent device 10 can exhibit excellent emission efficiency and lifetime characteristics.

[0219] In some embodiments, the organic electroluminescent device 10 according to an embodiment may include a plurality of emission layers EML. The plurality of emission layers EML may be provided by stacking them in sequence. For example, the organic electroluminescent device 10 including a plurality of emission layers EML may be used to emit white light. The organic electroluminescent device 10 including a plurality of emission layers EML may be an organic electroluminescent device having a tandem structure. When the organic electroluminescent device 10 includes a plurality of emission layers EML, at least one emission layer EML may include all of the first host, the second host, the first dopant, and the second dopant as described above.

[0220] In Figures 1 to 5 the organic electroluminescent device 10 of the embodiment shown, an electron transport region ETR is provided on the emission layer EML. The electron transport region ETR may include at least one of a hole blocking layer HBL, an electron transport layer ETL, and an electron injection layer EIL. However, embodiments of the present disclosure are not limited thereto.

[0221] The electron transport region ETR may have a single layer formed of a single material, a single layer formed of a plurality of different materials, or a multi-layer structure having a plurality of layers formed of a plurality of different materials.

[0222] For example, the electron transport region ETR may have a single layer structure including an electron injection layer EIL or an electron transport layer ETL, or a single layer structure formed using an electron injection material and an electron transport material (e.g., together). In addition, the electron transport region ETR may have a plurality of layers formed of a plurality of different materials, for example, a structure of an electron transport layer ETL / electron injection layer EIL or a hole blocking layer HBL / electron transport layer ETL / electron injection layer EIL stacked from the emission layer EML, without limitation. The thickness of the electron transport region ETR may be, for example, about to about

[0223] The electron transport region ETR may be formed using various suitable methods such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) method, inkjet printing, laser printing, and / or laser-induced thermal imaging (LITI) method.

[0224] If the electron transport region (ETR) includes an electron transport layer (ETL), the ETR may include anthracene compounds. The ETR may include, for example, tris(8-hydroxyquinoline) aluminum (Alq3), 1,3,5-tris[(3-pyridyl)-phenyl-3-yl]benzene, 2,4,6-tris(3′-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzimidazol-1-yl)phenyl)-9,10-dinaphthylanthracene, 1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene (TPBi), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), 3-(4-biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD), bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1′-biphenyl-4-ol) aluminum (BAlq), bis(benzoquinoline-10-hydroxy)beryllium (Bebq2), 9,10-bis(naphthalen-2-yl)anthracene (ADN), 1,3-bis[3,5-bis(pyridin-3-yl)phenyl]benzene (BmPyPhB), or mixtures thereof, without limitation. The thickness of the ETL may be about to about and may be, for example, about to about If the thickness of the ETL satisfies the above range, satisfactory electron transport properties can be obtained without a significant increase in the driving voltage.

[0225] If the ETR includes an electron injection layer (EIL), the ETR may include metal halides (such as LiF, NaCl, CsF, RbCl, RbI, and / or CuI), lanthanide metals (such as ytterbium (Yb)), metal oxides (such as Li2O and / or BaO), or lithium 8-hydroxyquinoline (LiQ). However, embodiments of the present disclosure are not limited thereto. For example, the EIL may be formed using a mixture of an electron transport material and an insulating organometallic salt. The insulating organometallic salt may be a material having a band gap of about 4 eV or greater. The insulating organometallic salt may include, for example, metal acetates, metal benzoates, metal acetoacetates, metal acetylacetonates, and / or metal stearates. The thickness of the EIL may be about to about or about to about If the thickness of the electron injection layer EIL satisfies the range described above, satisfactory electron injection properties can be obtained without causing a significant increase in the driving voltage.

[0226] As described above, the electron transport region ETR may include a hole blocking layer HBL. The hole blocking layer HBL may include at least one of, for example, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and 4,7-diphenyl-1,10-phenanthroline (Bphen). However, embodiments of the present disclosure are not limited thereto.

[0227] The second electrode EL2 is provided on the electron transport region ETR. The second electrode EL2 may be a common electrode or a cathode. The second electrode EL2 may be a transmissive electrode, a transmissive-reflective electrode, or a reflective electrode. If the second electrode EL2 is a transmissive electrode, the second electrode EL2 may include a transparent metal oxide, for example, ITO, IZO, ZnO, ITZO, etc. The thickness of the second electrode EL2 may be about to about For example, about to about

[0228] If the second electrode EL2 is a transmissive-reflective electrode or a reflective electrode, the second electrode EL2 may include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, their compounds, or their mixtures (for example, a mixture of Ag and Mg). The second electrode EL2 may have a multilayer structure that includes a reflective layer or a transmissive-reflective layer formed using the above materials and a transparent conductive layer formed using ITO, IZO, ZnO, ITZO, etc.

[0229] The second electrode EL2 may be connected to an auxiliary electrode. If the second electrode EL2 is connected to the auxiliary electrode, the resistance of the second electrode EL2 may be reduced.

[0230] Referring to Figure 4 , the organic electroluminescent device 10 of the embodiment may further include a buffer layer BFL between the emission layer EML and the electron transport region ETR. The buffer layer BFL may control the concentration of excitons generated in the emission layer EML. For example, the buffer layer BFL may include a part of the material of the emission layer EML. The buffer layer BFL may include a host material in the material of the emission layer EML. According to the combination of the host material and the dopant material included in the emission layer EML, the lowest triplet excitation energy level of the material of the buffer layer BFL may be controlled or selected to be equal to or greater than the lowest triplet excitation energy level of the second dopant, or equal to or less than the lowest triplet excitation energy level of the second dopant.

[0231] On the second electrode EL2 of the organic electroluminescent device 10 of the embodiment, a capping layer CPL may be further provided. The capping layer CPL may include, for example, α-NPD, NPB, TPD, m-MTDATA, Alq3, CuPc, N4,N4,N4′,N4′-tetrakis(biphenyl-4-yl)biphenyl-4,4′-diamine (TPD15), 4,4′,4″-tris(carbazol-9-yl)triphenylamine (TCTA), etc.

[0232] The compound of the embodiment may be included in a functional layer other than the emission layer EML as a material for the organic electroluminescent device 10. The organic electroluminescent device 10 according to an embodiment of the present disclosure may include the compound in at least one functional layer provided between the first electrode EL1 and the second electrode EL2 or in the capping layer CPL provided on the second electrode EL2.

[0233] As described above, the organic electroluminescent device 10 according to an embodiment of the present disclosure includes (e.g., optimizes) a combination of a host material and a dopant material of the emission layer EML, and may exhibit excellent emission efficiency and / or long-life characteristics. In addition, the organic electroluminescent device 10 of the embodiment may exhibit high efficiency and long-life characteristics in the blue wavelength region.

[0234] Hereinafter, the compound according to the embodiment and the organic electroluminescent device of the embodiment of the present disclosure will be explained in more detail with reference to the embodiment and the comparative embodiment. The following embodiments are merely illustrative for facilitating the understanding of the present disclosure, and the scope of the present disclosure is not limited thereto.

[0235] Examples

[0236] (Manufacture of Organic Electroluminescent Device)

[0237] The organic electroluminescent devices of the examples and the comparative examples were manufactured as follows. As the first electrode, an ITO glass substrate was cut into a size of 50 mm x 50 mm x 0.5 mm, cleaned with isopropyl alcohol and distilled water for 10 minutes each by ultrasonic waves, cleaned by exposure to ultraviolet rays and ozone for about 10 minutes, and installed in a vacuum deposition apparatus. Then, a hole injection layer HIL was formed using 2-MTDATA to a thickness of about and a hole transport layer HTL was formed using NPB to a thickness of about . Then, the first host, the second host, the first dopant, and the second dopant according to the embodiment were co-deposited to form an emission layer EML having a thickness of about , and an electron transport layer ETL was formed using the compound ETL1 (shown below) to a thickness of about . Then, Al was used to a thickness of about The thickness forms the second electrode. All layers are formed by a vacuum deposition method. When depositing the emission layer, the concentration of the first dopant is 15% and the concentration of the second dopant is 1%.

[0238]

[0239] The combinations of materials for the emission layer EML used in the examples and comparative examples are shown in Table 1.

[0240] [Table 1]

[0241]

[0242] In each device 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 light emission start wavelength of the first dopant, the light emission start wavelength of the second dopant, the normalized light intensity at the intersection point (wavelength intersection point) of the normalized light absorption spectrum and the normalized light emission spectrum of the second dopant, and the distance between the light absorption peak / light emission peak are shown in Table 2. When there are two or more hosts, two types of hosts form an exciplex, and in Table 2, the T1 and start wavelength of the exciplex are measured and described.

[0243] [Table 2]

[0244]

[0245] (Evaluation of the properties of the organic electroluminescent device)

[0246] The properties of the organic electroluminescent device are evaluated using a luminance light distribution characteristic measurement system. To evaluate the properties of the organic electroluminescent devices according to the examples and comparative examples, the efficiency and lifetime (T 95 ) are measured. At a current density of about 10 mA / cm 2 and a luminance of about 1,000 cd / m 2 , the emission efficiency (cd / A) of the thus fabricated organic electroluminescent device is measured. The device lifetime (T 95 ) is the period during which the luminance decreases from a standard of about 1,000 cd / m 2 (e.g., the initial luminance) to 95% of the initial luminance. The device lifetime (T 2 ) is measured by continuously (e.g., substantially continuously) driving at a current density of about 10 mA / cm 95 , and the result is shown in hours.

[0247] [Table 3]

[0248] Manufacturing example of the device Emission efficiency (cd / A) <![CDATA[Device life (T 95 , h) <!-- 37 -->]]> Example 1 23.6 31.1 Example 2 24.2 29.5 Example 3 24.1 38.6 Example 4 25.3 26.8 Example 5 25.1 26.1 Example 6 21.8 33.9 Example 7 22.8 35.5 Example 8 23.5 42.0 Example 9 24.4 37.1 Example 10 25.5 33.3 Comparative Example 1 17.8 0.5 Comparative Example 2 26.6 1.5 Comparative Example 3 19.1 21.2 Comparative Example 4 11.9 1.7 Comparative Example 5 16.3 7.6 Comparative Example 6 25.7 2.4 Comparative Example 7 11.5 10.8 Comparative Example 8 17.0 17.4 Comparative Example 9 2.7 1.8 Comparative Example 10 3.5 0.8 Comparative Example 11 15.8 17.2 Comparative Example 12 6.2 1.3 Comparative Example 13 1.1 0.2 Comparative Example 14 10.7 28.9 Comparative Example 15 4.1 1.2 Comparative Example 16 13.2 15.3

[0249] Referring to the results in Table 3, it can be confirmed that for each of the examples, the device emission efficiency and / or the device lifetime are improved when compared with the comparative examples, because the emission layer according to the embodiment includes all of the first host, the second host, the first dopant, and the second dopant, and the light emission start wavelength of the second dopant has a larger value than the light emission start wavelength of the first dopant.

[0250] In Comparative Examples 1, 2, and 4 to 9, one of the first host, the second host, the first dopant, and the second dopant is not included, and thus at least one of the efficiency and the lifetime is reduced when compared with the devices of the examples. Additionally, it can be confirmed that although each of Comparative Examples 3 and 10 to 16 includes all of the first host, the second host, the first dopant, and the second dopant, and the second dopant has a larger light emission start wavelength value than only one of the first dopant and the host, when compared with the light-emitting devices of the examples, Comparative Examples 3 and 10 to 16 show reduced emission efficiency and device lifetime.

[0251] In the organic electroluminescent device of the embodiment, the second dopant (which is a light emitter) has the largest light emission start wavelength, the first dopant (which functions as a co-dopant) has a light emission start wavelength smaller than that of the second dopant, and the host has the smallest light emission start wavelength. Accordingly, the energy transfer between the materials in the emission layer can be improved, and high emission efficiency and / or long lifetime characteristics can be achieved. Further, the organic electroluminescent device of the embodiment has a normalized light intensity of about 0.5 or more at the wavelength intersection point of the normalized light absorption spectrum and the normalized light emission spectrum of the second dopant (which is a light emitter), and the energy transfer from the host and the first dopant to the second dopant can be improved, and high emission efficiency and / or long lifetime characteristics can be shown.

[0252] The organic electroluminescent device of the embodiment can show improved device properties of high lifetime and / or high efficiency.

[0253] The organic electroluminescent device of the embodiment includes two host materials and two dopant materials, and can show high efficiency and long lifetime characteristics.

[0254] Although example embodiments of the present disclosure have been described, it should be understood that the present disclosure should not be limited to these example embodiments, but various changes and modifications can be made by those of ordinary skill in the art within the spirit and scope of the present disclosure as described in the appended claims and their equivalents.

Claims

1. An organic electroluminescent device, comprising: a first electrode; a second electrode opposite to the first electrode; and an emission layer between the first electrode and the second electrode, wherein the emission layer includes: a host having a first emission onset wavelength, wherein the first emission onset wavelength is the x-intercept value of a tangent drawn at a position where the light intensity is 0.5 in the normalized light emission spectrum of the host; a first dopant having a second emission onset wavelength, wherein the second emission onset wavelength is the x-intercept value of a tangent drawn at a position where the light intensity is 0.5 in the normalized light emission spectrum of the first dopant; and a second dopant different from the first dopant and having a third emission onset wavelength, wherein the third emission onset wavelength is the x-intercept value of a tangent drawn at a position where the light intensity is 0.5 in the normalized light emission spectrum of the second dopant, and the third emission onset wavelength is greater than each of the first emission onset wavelength and the second emission onset wavelength, wherein the normalized light intensity at the intersection of the normalized light absorption spectrum and the normalized light emission spectrum of the second dopant is 0.5 or greater, wherein the distance between the peak of the normalized light absorption spectrum and the peak of the normalized light emission spectrum of the second dopant is 50 nm or less, wherein the normalized light emission spectrum is obtained by dissolving the host, the first dopant or the second dopant in an organic solvent and dividing it by the maximum value of the first peak after measuring the emission spectrum, and wherein the normalized light absorption spectrum is obtained by dissolving the host, the first dopant or the second dopant in an organic solvent and dividing it by the maximum value of the first peak after measuring the absorption spectrum.

2. The organic electroluminescent device according to claim 1, wherein the second dopant has a lower lowest triplet excitation energy level than each of the host and the first dopant.

3. The organic electroluminescent device according to claim 1, wherein the host includes a first host and a second host different from the first host.

4. The organic electroluminescent device according to claim 3, wherein the first host is represented by formula H-1: [Formula H-1] wherein in formula H-1, L1 is a direct bond, a substituted or unsubstituted arylene having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroarylene having 2 to 30 ring-forming carbon atoms, Ar1 is a substituted or unsubstituted aryl having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroaryl having 2 to 30 ring-forming carbon atoms, "a” and "b” are each independently an integer selected from 0 to 4, and R1 and R2 are each independently a substituted or unsubstituted aryl having 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroaryl having 2 to 30 ring-forming carbon atoms.

5. The organic electroluminescent device according to claim 3, wherein the second host is represented by formula H-2: [Formula H-2] wherein in formula H-2, Z1 to Z3 are each independently CR y or N, and R y and R 11 to R 13 each independently represents 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 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring.

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

7. The organic electroluminescent device according to claim 6, wherein the first dopant is represented by Formula D-1: [Formula D-1] Wherein in Formula D-1, M is Pt, Pd, Cu, Os, Ir, Ru, or Rh, Q1 to Q4 are each independently C or N, 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, L 21 to L 23 each independently is a direct bond, *-O-*, *-S-*, a substituted or unsubstituted divalent alkyl group having 1 to 20 carbon atoms, 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, e1 to e3 are each independently 0 or 1, R 21 to R 26 each independently is 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 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, or each combines with an adjacent group to form a ring d1 to d4 are each independently an integer selected from 0 to 4. When M is Pt, Pd, Cu, or Os, "m" is 1, and when M is Ir, Ru, or Rh, "m" is 2, and e2 is 0, and -* indicates a connecting position.

8. The organic electroluminescent device according to claim 1, wherein the second dopant is represented by Formula D-2a: [Formula D-2a] In formula D-2a, X1 and X2 are each independently NR m or O, 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, and 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 boron 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 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, or each combines with an adjacent group to form a ring.

9. The organic electroluminescent device according to claim 1, wherein the second dopant is represented by Formula D-2b: [Formula D-2b] D1-L2-A1, Wherein in Formula D-2b, L2 is a direct bond, a substituted or unsubstituted arylene having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene having 2 to 30 ring-forming carbon atoms, and D1 is represented by Formula D-2-1 or Formula D-2-2: Wherein in Formula D-2-1 and Formula D-2-2, L3 and L4 are each independently a direct bond or a substituted or unsubstituted arylene having 6 to 30 ring-forming carbon atoms, R 42 to R 59 each independently represents 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 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, or each combines with an adjacent group to form a ring, Y1 is a direct connection, CR a R b , SiR c R d , GeR e R f , NR g , O or S, R a to R g each independently is a substituted or unsubstituted alkyl group having 1 to 15 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, R a and R b 、R c and R d ,and / or R e and R f optionally combine with each other to form a ring, and A1 is represented by one of Formulas D-2-3 to D-2-10: Y2 is C=O or S(=O)2, Y3 is C=O or O, Y4 and Y5 are each independently O or S, Y6 and Y7 are each independently N or CQ 12 , Y8 is O or NQ 13 , Q1 to Q 13 each independently is 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 an integer selected from 0 to 4, n3, n5, n7, n8, and n10 are each independently an integer selected from 0 to 3, n2 is an integer selected from 0 to 5, n9 is an integer selected from 0 to 2, and The connection position.

10. The organic electroluminescent device according to claim 3, wherein the weight ratio of the first host to the second host is from 7:3 to 3:

7.

11. The organic electroluminescent device according to claim 3, wherein: Based on the total weight of the first host, the second host, the first dopant, and the second dopant, the amount of the first dopant is 10 wt% to 15 wt%, and the amount of the second dopant is 1 wt% to 5 wt%.

12. The organic electroluminescent device according to claim 3, wherein the first host includes at least one selected from the compounds represented in Compound Group 1: [Compound Group 1] 13. The organic electroluminescent device according to claim 3, wherein the second host includes at least one selected from the compounds represented in Compound Group 2-1 and Compound Group 2-2: [Compound group 2-1] [Compound group 2-2] 14. The organic electroluminescent device according to claim 1, wherein the first dopant comprises at least one selected from the compounds represented in compound group 3-1 and compound group 3-2: [Compound group 3-1] [Compound group 3-2] Wherein in AD2-1 to AD2-4, AD2-13 to AD2-16 and AD2-25 to AD2-28, each R is independently a hydrogen atom, a methyl group, an isopropyl group, a tert-butyl group or a dimethylamino group.

15. The organic electroluminescent device according to claim 1, wherein the second dopant comprises at least one selected from the compounds represented in compound group 4-1 and compound group 4-2: [Compound group 4-1] [Compound group 4-2]

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