Organic electroluminescent device and spiro compound for organic electroluminescent device

Abstract

According to an embodiment, the organic electroluminescent device includes: a first electrode; a hole transport region disposed on the first electrode; a light-emitting layer disposed on the hole transport region; an electron transport region disposed on the light-emitting layer; and a second electrode disposed on the electron transport region, wherein the light-emitting layer includes a spiro compound containing an arylamine group and an indenoindole derivative, and can therefore exhibit high luminescence efficiency and emit green light.

Description

Technical Field

[0001] The present invention disclosed herein relates to an organic electroluminescent device and a spiro compound used in an organic electroluminescent device. Background Art

[0002] Recently, development of organic electroluminescent displays as image displays is being actively carried out. Unlike liquid crystal displays, organic electroluminescent displays are so-called self-luminescent displays in which holes and electrons injected from the first electrode and the second electrode are recombined in the emission layer, so that the light-emitting material including organic compounds in the emission layer emits light to achieve display.

[0003] When organic electroluminescent devices are applied to displays, the driving voltage of the organic electroluminescent devices is required to be reduced and the emission efficiency and life span are increased, and the development of materials for organic electroluminescent devices that stably achieve these requirements is constantly being required.

[0004] Specifically, recently, in order to realize an organic electroluminescent device with high efficiency, technology regarding phosphorescence emission (which uses triplet energy) or delayed fluorescence emission (which uses a phenomenon of generating singlet excitons by collision of triplet excitons (triplet-triplet annihilation, TTA)) is being developed, and development of materials for thermally activated delayed fluorescence (TADF) using the delayed fluorescence phenomenon is being conducted. Summary of the invention

[0005] Technical issues

[0006] An object of the present invention is to provide an organic electroluminescent device with improved green emission efficiency.

[0007] Another object of the present invention is to provide a spiro compound capable of improving emission efficiency.

[0008] Technical Solution

[0009] An embodiment of the present invention provides an organic electroluminescent device, comprising: a first electrode; a hole transport region disposed on the first electrode; an emission layer disposed on the hole transport region; an electron transport region disposed on the emission layer; and a second electrode disposed on the electron transport region, wherein the emission layer comprises a spiro compound comprising an arylamine group (or an arylamino group) and an indenoindole derivative, and emits green light.

[0010] In the spiro compound, the indenoindole derivative and the pentagonal ring or the hexagonal ring may form a spiro connection.

[0011] The indenoindole derivative and the arylamine group may be bound via a linker or via a direct bond.

[0012] The emitting layer may be a thermally activated delayed fluorescent emitting layer.

[0013] The spiro compound may have an absolute value of a difference between a singlet energy level and a triplet energy level of 0.2 eV or less.

[0014] The emission layer may include a host and a dopant, and the dopant may include a spiro compound.

[0015] The spiro compound can be represented by Formula 1 below.

[0016] [Formula 1]

[0017]

[0018] In formula 1, R 1 and R 2 are independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycloalkyl group having 2 to 30 ring carbon atoms, or combine with an adjacent group to form a ring, Ar 1 is a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycloalkyl group having 2 to 30 ring carbon atoms, Ar 2 and Ar 3 are independently a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, L 1 is a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring carbon atoms, a is an integer from 0 to 3, l is an integer from 0 to 4, and Z 1 and Z 2 A spiro connection of a ring compound represented by the following formula 2 is formed.

[0019] [Formula 2]

[0020]

[0021] In formula 2, X 1 It is a direct key, O, S, CR 5 R 6 、SiR 7 R 8 , BR 9 or NR 10, X 2 To X 5 Both are independently CR 11 R 12 , and R 5 To R 12 Each is independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, a substituted or unsubstituted aryl group of 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group of 2 to 30 ring carbon atoms, or combines with an adjacent group to form a ring.

[0022] Formula 2 can be represented by any one selected from the following Formulas 2-1 to 2-7.

[0023] [Formula 2-1]

[0024]

[0025] [Formula 2-2]

[0026]

[0027] [Formula 2-3]

[0028]

[0029] [Formula 2-4]

[0030]

[0031] [Formula 2-5]

[0032]

[0033] [Formula 2-6]

[0034]

[0035] [Formula 2-7]

[0036]

[0037] In Formula 2-1 to Formula 2-7, R 3 and R 4 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycloalkyl group having 2 to 30 ring carbon atoms, or combine with an adjacent group to form a ring, m and n are each independently an integer from 0 to 4, and R 5 To R10 Same as defined in Formula 2.

[0038] Formula 1 can be represented by the following formula 3.

[0039] [Formula 3]

[0040]

[0041] In formula 3, R 3 and R 4 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycloalkyl group having 2 to 30 ring carbon atoms, or combine with an adjacent group to form a ring, m and n are each independently an integer from 0 to 4, and R 1 , R 2 , R 5 To R 10 ,Ar 1 To Ar 3 , L 1 , X 1 , a and l are the same as defined in Formula 1 and Formula 2.

[0042] An embodiment of the present invention provides an organic electroluminescent device, comprising: a first electrode; a hole transport region disposed on the first electrode; an emission layer disposed on the hole transport region; an electron transport region disposed on the emission layer; and a second electrode disposed on the electron transport region, wherein the emission layer comprises a spiro compound represented by the following formula 1.

[0043] [Formula 1]

[0044]

[0045] In formula 1, R 1 and R 2 are independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycloalkyl group having 2 to 30 ring carbon atoms, or combine with an adjacent group to form a ring, Ar 1is a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycloalkyl group having 2 to 30 ring carbon atoms, Ar 2 and Ar 3 are independently a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, L 1 is a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring carbon atoms, a is an integer from 0 to 3, l is an integer from 0 to 4, and Z 1 and Z 2 A spiro connection of a ring compound represented by the following formula 2 is formed.

[0046] [Formula 2]

[0047]

[0048] In formula 2, X 1 It is a direct key, O, S, CR 5 R 6 、SiR 7 R 8 , BR 9 or NR 10 , X 2 To X 5 Both are independently CR 11 R 12 , and R 5 To R 12 Each is independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, a substituted or unsubstituted aryl group of 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group of 2 to 30 ring carbon atoms, or combines with an adjacent group to form a ring.

[0049] The present invention provides a spiro compound represented by the following Formula 1.

[0050] [Formula 1]

[0051]

[0052] In formula 1, R 1 and R 2are independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycloalkyl group having 2 to 30 ring carbon atoms, or combine with an adjacent group to form a ring, Ar 1 is a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycloalkyl group having 2 to 30 ring carbon atoms, Ar 2 and Ar 3 are independently a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, L 1 is a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring carbon atoms, a is an integer from 0 to 3, l is an integer from 0 to 4, and Z 1 and Z 2 A spiro connection of a ring compound represented by the following formula 2 is formed.

[0053] [Formula 2]

[0054]

[0055] In formula 2, X 1 It is a direct key, O, S, CR 5 R 6 、SiR 7 R 8 , BR 9 or NR 10 , X 2 To X 5 Both are independently CR 11 R 12 , and R 5 To R 12 Each is independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, a substituted or unsubstituted aryl group of 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group of 2 to 30 ring carbon atoms, or combines with an adjacent group to form a ring.

[0056] Beneficial Effects

[0057] The organic electroluminescent device according to the embodiment of the present invention can achieve high efficiency and long life in the green emission region.

[0058] The spiro compounds according to the embodiments of the present invention can improve the lifespan and efficiency of an organic electroluminescent device. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 is a cross-sectional view schematically showing an organic electroluminescent device according to an embodiment of the present invention.

[0060] Figure 2 is a cross-sectional view schematically showing an organic electroluminescent device according to an embodiment of the present invention.

[0061] Figure 3 is a cross-sectional view schematically showing an organic electroluminescent device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0062] The present invention may have various modifications and may be implemented in different forms, and exemplary embodiments will be explained in detail with reference to the accompanying drawings. However, the present invention may be implemented in different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, all modifications, equivalents, and substitutions included in the spirit and technical scope of the inventive concept should be included in the present invention.

[0063] The same reference numerals always refer to the same elements. In addition, in the accompanying drawings, in order to effectively explain the technical content, the sizes of the constituent elements are exaggerated. It will be understood that, although the terms first, second, etc. can be used to describe various elements here, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the teachings of the present invention, the first element can be named as the second element. Similarly, the second element can be named as the first element. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form.

[0064] It will also be understood that when the terms "comprise" and / or "include" and variations thereof are used in this specification, it indicates the presence of the stated features, numbers, steps, operations, elements, parts, or combinations thereof, but does not exclude the presence or addition of one or more other features, numbers, steps, operations, elements, parts, or combinations thereof. In addition, it will be understood that when a part including a layer, film, region, plate, etc. is referred to as being "on" another part, the part may be "directly on" the other part, or there may be an intervening third part.

[0065] In the following, reference will be made to Figures 1 to 3 An organic electroluminescent device according to an embodiment of the present invention is explained.

[0066] Reference Figures 1 to 3, the organic electroluminescent device 10 according to the 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 that are sequentially stacked.

[0067] The first electrode EL1 and the second electrode EL2 are arranged opposite to each other, and a plurality of organic layers may be arranged between the first electrode EL1 and the second electrode EL2. The plurality of organic layers may include a hole transport region HTR, an emission layer EML, and an electron transport region ETR. The organic electroluminescent device 10 of the embodiment may include the above-mentioned spiro compound of the embodiment in the emission layer EML.

[0068] At the same time, when Figure 1 When compared, Figure 2 1 shows a cross-sectional view of an organic electroluminescent device 10 of an 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 1 When compared, Figure 3 A cross-sectional view of an organic electroluminescent device 10 of an embodiment is shown, wherein a hole transport region HTR includes a hole injection layer HIL, a hole transport layer HTL and an electron blocking layer EBL, and an electron transport region ETR includes an electron injection layer EIL, an electron transport layer ETL and a hole blocking layer HBL.

[0069] Figures 1 to 3 The organic electroluminescent device 10 of the embodiment shown in may include the spiro compound of the embodiment in at least one organic layer among a plurality of organic layers.

[0070] In the organic electroluminescent device 10 of the embodiment, the first electrode EL1 has conductivity. The first electrode EL1 may be formed using a metal alloy or a conductive compound. The first electrode EL1 may be an anode.

[0071] The first electrode EL1 may be a transmissive electrode, a transflective electrode or a reflective electrode. If the first electrode EL1 is a transmissive electrode, the first electrode EL1 may be formed using a transparent metal oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), etc. If the first electrode EL1 is a transflective electrode or a reflective electrode, the first electrode EL1 may include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, a compound thereof, or a mixture thereof (e.g., a mixture of Ag and Mg). Alternatively, a structure including a plurality of layers may be formed, the plurality of layers including a reflective layer or a transflective layer formed using the above materials and a transmissive conductive layer formed using indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), etc. For example, the first electrode EL1 may include a multilayer structure of ITO / Ag / ITO.

[0072] The hole transport region HTR is disposed on the first electrode EL1. The hole transport region HTR may include at least one of a hole injection layer HIL, a hole transport layer HTL, a hole buffer layer, and an electron blocking layer EBL.

[0073] The hole transport region HTR may have a single layer formed using a single material, a single layer formed using a plurality of different materials, or a multi-layered structure including a plurality of layers formed using a plurality of different materials.

[0074] For example, the hole transport region HTR may have a single layer structure of a hole injection layer HIL or a hole transport layer HTL, and may have a single layer structure formed using a hole injection material and a hole transport material. Alternatively, the hole transport region HTR may have a single layer structure formed using a plurality of different materials, or a structure of a hole injection layer HIL / hole transport layer HTL, a hole injection layer HIL / hole transport layer HTL / hole buffer layer, 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 stacked from the first electrode EL1, but the embodiment is not limited thereto.

[0075] The hole transport region HTR may be formed using various methods such as a vacuum deposition method, a spin coating method, a casting method, a Langmuir-Blodgett (LB) method, an inkjet printing method, a laser printing method, and a laser induced thermal imaging (LITI) method.

[0076] The hole injection layer HIL of the organic electroluminescent device 10 of the embodiment may include a well-known hole injection material. For example, the hole injection layer HIL may include triphenylamine-containing polyetherketone (TPAPEK), 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate (PPBI), N,N'-diphenyl-N,N'-bis-[4-(di-m-tolyl-amino)-phenyl]-biphenyl-4,4'-diamine (DNTPD), a phthalocyanine compound such as copper phthalocyanine, 4,4',4"-tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA), N,N'-di(1-naphthyl)-N,N'-diphenylbenzidine (NPB), N,N'-di(1-naphthyl)-N,N'-diphenyl-4,4'-diamine (α-NPD), 4,4',4"-tri{N,N-diphenylamino}triphenylamine (TDATA), 4,4',4"-tri(N,N-2-naphthylphenylamino)triphenylamine (2-TNATA), polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (PANI / CSA), polyaniline / poly(4-styrenesulfonate) (PANI / PSS), or dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN). However, the embodiment is not limited thereto.

[0077] The hole transport layer HTL of the organic electroluminescent device 10 of the embodiment may include a well-known hole transport material. For example, the hole transport layer HTL may include 1,1-bis[(4-dimethylamino)phenyl]cyclohexane (TAPC), carbazole derivatives (such as N-phenylcarbazole and polyvinylcarbazole), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD), 4,4',4"-tri(N-carbazolyl)triphenylamine (TCTA) or N,N'-di(1-naphthyl)-N,N'-diphenylbenzidine (NPB), N,N'-bis(1-naphthyl)-N,N'-diphenyl-4,4'-diamine (α-NPD), etc. However, the embodiment is not limited thereto.

[0078] Meanwhile, the hole transport region HTR may further include an electron blocking layer EBL, and the electron blocking layer EBL may be disposed between the hole transport layer HTL and the emission layer EML. The electron blocking layer EBL may be a layer that functions to prevent electrons from being injected from the electron transport region ETR to the hole transport region HTR.

[0079] The electron blocking layer EBL may include common materials known in the art. The electron blocking layer EBL may include, for example, carbazole derivatives (such as N-phenylcarbazole and polyvinylcarbazole), fluorene derivatives, N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD), triphenylamine derivatives (such as 4,4',4"-tri(N-carbazolyl)triphenylamine (TCTA)), N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPD), 4,4'-cyclohexylenebis[N,N-bis(4-methylphenyl)aniline] (TAPC), 4,4'-bis[N,N'-(3-tolyl)amino]-3,3'-dimethylbiphenyl (HMTPD) or mCP.

[0080] 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, the hole injection layer HIL, the hole transport layer HTL, and the electron blocking layer EBL satisfy the above ranges, a satisfactory degree of hole transport properties may be achieved without significantly increasing driving voltage.

[0081] In addition to the above materials, the hole transport region HTR may further include a charge generating material to increase conductivity. The charge generating material may be uniformly or unevenly dispersed in the hole transport region HTR. The charge generating material may be, for example, a p-dopant. The p-dopant may be one of a quinone derivative, a metal oxide, and a cyano compound, without limitation. For example, non-limiting examples of p-dopants may include quinone derivatives (such as tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ)), metal oxides (such as tungsten oxide and molybdenum oxide), etc., without limitation.

[0082] 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 light emitted from the emission layer EML, and may improve the luminous efficiency. The material that may be included in the hole transport region HTR may be used as the material included in the hole buffer layer.

[0083] The emission layer EML is disposed on the hole transport region HTR. The emission layer EML may have, for example, about to The emission layer EML may have a single layer formed using a single material, a single layer formed using a plurality of different materials, or a multi-layered structure having a plurality of layers formed using a plurality of different materials.

[0084] The emission layer EML may emit one of red light, green light, blue light, white light, yellow light, and cyan light. The emission layer EML may include a fluorescent emission material or a phosphorescent emission material.

[0085] In an embodiment, the emission layer EML may be a fluorescent emission layer. For example, a portion of the light emitted from the emission layer EML may be caused by thermally activated delayed fluorescence (TADF). Specifically, the emission layer EML may include a luminescent component that emits thermally activated delayed fluorescence, and in an embodiment, the emission layer EML may be a thermally activated delayed fluorescence emission layer that emits green light.

[0086] In the organic electroluminescent device 10 of the embodiment, the emission layer EML includes a spiro compound including an arylamine group and an indenoindole derivative.

[0087] In an embodiment, the emission layer EML may include a host and a dopant, and the dopant may include a spiro compound including an arylamine group and an indenoindole derivative.

[0088] In an embodiment, in the spiro compound, the indenoindole derivative and the pentagonal ring or the hexagonal ring may form a spiro connection, and the indenoindole derivative and the arylamine group may be combined via a linker or may form a direct bond.

[0089] In the specification, -* means the position to be connected.

[0090] In the specification, a direct bond may mean a single bond.

[0091] In the specification, the term "substituted or unsubstituted" corresponds to being unsubstituted or substituted with one or more substituents selected from the group consisting of a deuterium atom, a halogen atom, a cyano group, a nitro group, an amino group, a silyl group, a boron group, a phosphine oxide group, a phosphine sulfide group, an alkyl group, an alkenyl group, an aryl group, and a heterocyclic group. In addition, each of the exemplified substituents may be substituted or unsubstituted. For example, a biphenyl group may be interpreted as an aryl group or a phenyl group substituted with a phenyl group.

[0092] In the specification, the term "forming a ring by combining with an adjacent group" may mean forming a substituted or unsubstituted hydrocarbon ring or a substituted or unsubstituted heterocycle by combining with an adjacent group. The hydrocarbon ring includes an aliphatic hydrocarbon ring and an aromatic hydrocarbon ring. The heterocycle includes an aliphatic heterocycle and an aromatic heterocycle. The ring formed by combining with an adjacent group may be a monocyclic ring or a polycyclic ring. In addition, the ring formed by combining with an adjacent group may be combined with another ring to form a spiro ring structure.

[0093] In the specification, the term "adjacent group" may mean a substituent that replaces an atom directly bonded to an atom substituted by a corresponding substituent, another substituent that replaces an atom substituted by a corresponding substituent, or a substituent that is spatially adjacent to a corresponding substituent. For example, in 1,2-xylene, two methyl groups may be interpreted as "adjacent groups" to each other, and in 1,1-diethylcyclopentane, two ethyl groups may be interpreted as "adjacent groups" to each other.

[0094] In the specification, examples of the halogen atom may include a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

[0095] In the specification, unless otherwise classified, the alkyl group may be a chain type or a cyclic type. The carbon number of the alkyl group may be 1 to 50, 1 to 30, 1 to 20, 1 to 10, or 1 to 6. Examples of the alkyl group may include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, 2-ethylbutyl, 3,3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, 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-butyloctyl, 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-butylhexadecyl, 2-hexylhexadecyl, 2-octylhexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, 2-ethyleicosyl, 2-butyleicosyl, 2-hexyleicosyl, 2-octyleicosyl, n-heneicosyl, n-docosyl, n-tricosyl, n-tetracosyl, n-pentacosyl, n-hexacosyl, n-heptacosyl, n-octacosyl, n-nonacosyl, n-triacontyl and the like without limitation.

[0096] In the specification, aryl means an optional functional group or substituent derived from an aromatic hydrocarbon ring. The aryl group may be a monocyclic aryl group or a polycyclic aryl group. The number of carbon atoms in the aryl group used for ring formation may be 6 to 30, 6 to 20, or 6 to 15. Examples of aryl groups may include phenyl, naphthyl, fluorenyl, anthracenyl, phenanthrenyl, biphenyl, terphenyl, quaterphenyl, pentaphenyl, hexaphenyl, benzo[9,10]phenanthrenyl, pyrenyl, benzofluoranthenyl, Base, etc., but the embodiment is not limited thereto.

[0097] In the specification, the fluorenyl group may be substituted, and two substituents may be combined with each other to form a spiro ring structure. Examples of substituted fluorenyl groups are as follows. However, the embodiment is not limited thereto.

[0098]

[0099] In the specification, the heteroaryl group may include one or more of O, N, P, Si and S as a heteroatom. The number of ring carbon atoms of the heteroaryl group may be 2 to 30 or 2 to 20. The heteroaryl group may be a monocyclic heteroaryl group or a polycyclic heteroaryl group. The polycyclic heteroaryl group may have, for example, a bicyclic structure or a tricyclic structure. Examples of heteroaryl groups may include thienyl, furyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, oxadiazolyl, triazolyl, pyridyl, bipyridyl, pyrimidyl, triazinyl, acridinyl, pyridazinyl, pyrazinyl, quinolyl, quinazolinyl, quinoxalinyl, phenoxazinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolyl, indolyl, carbazolyl, N-arylcarbazolyl, N-heteroarylcarbazolyl, N-alkylcarbazolyl, benzoxazolyl, benzimidazolyl, benzothiazolyl, benzocarbazolyl, benzothienyl, dibenzothienyl, thienothiphenyl, benzofuranyl, phenanthrolinyl, isoxazolyl, thiadiazolyl, phenothiazinyl, dibenzosilyl, dibenzofuranyl, and the like without limitation.

[0100] In the specification, silyl includes alkylsilyl and arylsilyl. Examples of silyl may include trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, vinyldimethylsilyl, propyldimethylsilyl, triphenylsilyl, diphenylsilyl, phenylsilyl, etc. However, the embodiment is not limited thereto.

[0101] In the specification, the carbon number of the amine group is not particularly limited, but can be 1 to 30. The amine group can include an alkylamine group and an arylamine group. Examples of the amine group include methylamine group, dimethylamine group, phenylamine group, naphthylamine group, 9-methyl-anthrylamine group, etc., without limitation.

[0102] Refer again Figures 1 to 3, the emission layer EML may include a spiro compound represented by Formula 1 below.

[0103] [Formula 1]

[0104]

[0105] In formula 1, R 1 and R 2 Each of them may independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycloalkyl group having 2 to 30 ring carbon atoms, or may combine with an adjacent group to form a ring.

[0106] In formula 1, Ar 1 It may be a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycloalkyl group having 2 to 30 ring carbon atoms.

[0107] In an embodiment, the substituted or unsubstituted Ar 1 In the formula (a), one to eight substituents may be present, and in the case of two or more substituents, the substituents may be the same or different.

[0108] In the embodiment, in Ar 1 In the case of one or more substituents, Ar 1 The substituent may be a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycloalkyl group having 2 to 30 ring carbon atoms.

[0109] In the embodiment, Ar 1 It may be a substituted or unsubstituted phenyl group, a substituted or unsubstituted pyridyl group, a substituted or unsubstituted pyrimidyl group, or a substituted or unsubstituted triazinyl group.

[0110] In formula 1, Ar 2 and Ar 3 Each may independently be a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms.

[0111] The spiro compound according to the present invention includes an arylamine group, and the core structure itself has a distorted stereostructure. Due to this steric effect, the triplet energy level value can be increased, and the absolute value of the difference between the singlet energy level and the triplet energy level (ΔEst) can be reduced.

[0112] In formula 1, L 1 It may be a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring carbon atoms.

[0113] In an embodiment, L 1 Can be a direct key.

[0114] In Formula 1, a is an integer from 0 to 3, and l is an integer from 0 to 4. Meanwhile, if a is 2 or more, a plurality of R 1 The groups are the same or different, and if l is 2 or greater, then multiple R 2 The groups may be the same or different.

[0115] In formula 1, Z 1 and Z 2 A spiro connection of a ring compound represented by the following formula 2 is formed.

[0116] [Formula 2]

[0117]

[0118] In formula 2, X 1 Can be direct key, O, S, CR 5 R 6 、SiR 7 R 8 , BR 9 or NR 10 .

[0119] In formula 2, X 2 To X 5 Can be CR independently 11 R 12 .

[0120] In formula 2, R 5 To R 12 Each may independently be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, a substituted or unsubstituted aryl group of 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group of 2 to 30 ring carbon atoms, or may combine with an adjacent group to form a ring.

[0121] In the spirocyclic compound according to the present invention, Z 1 and Z 2and the cyclic compound represented by Formula 2 forms a spiro connection, therefore, the sp 3 Carbon can be protected, durability at high temperatures can become excellent, and thermal decomposition under high temperature conditions can be difficult to occur, and the life of the device can be increased.

[0122] In an embodiment, Formula 2 may be expressed by any one of the following Formulas 2-1 to 2-7.

[0123] [Formula 2-1]

[0124]

[0125] [Formula 2-2]

[0126]

[0127] [Formula 2-3]

[0128]

[0129] [Formula 2-4]

[0130]

[0131] [Formula 2-5]

[0132]

[0133] [Formula 2-6]

[0134]

[0135] [Formula 2-7]

[0136]

[0137] In Formula 2-1 to Formula 2-7, R 3 and R 4 Each of them may independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycloalkyl group having 2 to 30 ring carbon atoms, or may combine with an adjacent group to form a ring.

[0138] In Formula 2-1 to Formula 2-7, m and n are each independently an integer of 0 to 4. Meanwhile, if m is 2 or greater, a plurality of R 3 The groups are the same or different, and if n is 2 or greater, then multiple R 4 The groups may be the same or different.

[0139] Formula 2-1 represents that X 1 is the direct bond formula 2, formula 2-2 represents where X 1 is O's formula 2, formula 2-3 represents that X 1 is the formula 2 of S, and formula 2-4 represents that X 1 Yes CR 5 R 6 Formula 2, Formula 2-5 represents that X 1 It is SiR 7 R 8 In addition, Formula 2-6 represents that X 1 Yes BR 9 Formula 2, Formula 2-7 represents that X 1 YesNR 10 Formula 2.

[0140] At the same time, in Formula 2-1 to Formula 2-7, the reference formula 2 can be applied to R 5 To R 10 The same explanation.

[0141] In an embodiment, Formula 1 may be represented by Formula 3 below.

[0142] [Formula 3]

[0143]

[0144] In formula 3, R 3 and R 4 Each of them may independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycloalkyl group having 2 to 30 ring carbon atoms, or may combine with an adjacent group to form a ring.

[0145] In Formula 3, m and n are each independently an integer of 0 to 4. Meanwhile, if m is 2 or greater, a plurality of R 3 The groups are the same or different, and if n is 2 or greater, then multiple R 4 The groups may be the same or different.

[0146] In formula 3, R 1 , R 2 , R 5 To R 10 ,Ar 1 To Ar 3 , L 1 , X 1, a and l are the same as defined in Formula 1 and Formula 2.

[0147] Formula 3 can be expressed by any one of the following Formulas 3-1 to 3-5.

[0148] [Formula 3-1]

[0149]

[0150] [Formula 3-2]

[0151]

[0152] [Formula 3-3]

[0153]

[0154] [Formula 3-4]

[0155]

[0156] [Formula 3-5]

[0157]

[0158] In Formula 3-1 to Formula 3-5, R 1 To R 8 ,Ar 1 To Ar 3 , L 1 , a and l to n are the same as defined in Formula 3.

[0159] In an embodiment, Formula 3 may be represented by the following Formula 4-1 or Formula 4-2.

[0160] [Formula 4-1]

[0161]

[0162] [Formula 4-2]

[0163]

[0164] In equations 4-1 and 4-2, X 1 , R 1 To R 10 ,Ar 1 To Ar 3 , L 1 , a and l to n are the same as defined in Formula 3.

[0165] The spiro compound of the embodiment represented by Formula 1 may be a material emitting delayed fluorescence. The spiro compound of the embodiment may be a material emitting thermally activated delayed fluorescence.

[0166] The spiro compound of the embodiment represented by Formula 1 may have an absolute value (ΔEst) of a difference between a singlet energy level (S1) and a triplet energy level (T1) of 0.2 eV or less. For example, |S1-T1|≤0.2 eV may be satisfied.

[0167] For example, the spiro compound represented by Formula 1 has a small difference between the singlet energy level (S1) and the triplet energy level (T1), and can be used as a material emitting thermally activated delayed fluorescence. Specifically, the spiro compound represented by Formula 1 can be used as a green light-emitting material emitting thermally activated delayed fluorescence. However, the embodiment is not limited thereto, and the spiro compound of the embodiment can be a material emitting thermally activated delayed fluorescence emitting blue light or red light.

[0168] The spiro compound represented by Formula 1 may be represented by any one of the compounds represented in Compound Group 1 below.

[0169] [Compound Group 1]

[0170]

[0171]

[0172]

[0173]

[0174] The spiro compound represented by Formula 1 can be used in the organic electroluminescent device 10 of the embodiment, and can improve the efficiency and life of the organic electroluminescent device. Specifically, the spiro compound represented by Formula 1 can be used in the emission layer EML of the organic electroluminescent device 10 of the embodiment, and can improve the emission efficiency and life of the organic electroluminescent device.

[0175] In an embodiment, the emission layer EML includes a host and a dopant, the host may be a host for emitting delayed fluorescence, and the dopant may be a dopant emitting delayed fluorescence. At the same time, the spiro compound of the embodiment represented by Formula 1 may be included as a dopant material of the emission layer EML. For example, the spiro compound of the embodiment represented by Formula 1 may be used as a TADF dopant.

[0176] In an embodiment, the emission layer EML may include a known host material. For example, in an embodiment, the emission layer EML may include tris(8-hydroxyquinoline)aluminum (Alq 3)、4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP), poly(N-vinylcarbazole) (PVK), 9,10-di(naphthalene-2-yl)anthracene (ADN), 4,4',4"-tri(carbazol-9-yl)-triphenylamine (TCTA), 1,3,5-tri(N-phenylbenzimidazol-2-yl)benzene (TPBi), 2-tert-butyl-9,10-di(naphthalene-2-yl)anthracene (TBADN), distyrylarylenes distyrylarylene (DSA), 4,4'-bis(9-carbazolyl)-2,2'-dimethyl-biphenyl (CDBP), 2-methyl-9,10-bis(naphthalene-2-yl)anthracene (MADN), bis[2-(diphenylphosphino)phenyl]ether oxide (DPEPO), hexaphenylcyclotriphosphazene (CP1), 1,4-bis(triphenylsilyl)benzene (UGH2), hexaphenylcyclotrisiloxane (DPSiO 3 ), octaphenylcyclotetrasiloxane (DPSiO 4 ) or 2,8-bis(diphenylphosphoryl)dibenzofuran (PPF), etc. However, the embodiment is not limited thereto, and may include any known host material for emitting delayed fluorescence other than the suggested host material.

[0177] Meanwhile, in the organic electroluminescent device 10 of the embodiment, the emission layer EML may include a known dopant material. In the embodiment, the emission layer EML may include a styryl derivative (e.g., 1,4-bis[2-(3-N-ethylcarbazolyl)vinyl]benzene (BCzVB), 4-(di-p-tolylamino)-4'-[(di-p-tolylamino)styryl]stilbene (DPAVB) and N-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl)naphthalene-2-yl)vinyl)phenyl)-N-phenylaniline (N-BDAVBi)), perylene and its derivatives (e.g., 2,5,8,11-tetra-tert-butylperylene (TBP)), pyrene and its derivatives (e.g., 1,1'-dipyrene, 1,4-dipyrenylbenzene and 1,4-bis(N,N-diphenylamino)pyrene), etc. as a dopant.

[0178] Refer again Figures 1 to 3 In the organic electroluminescent device 10 of the embodiment, the electron transport region ETR is disposed on the emission layer EML. The electron transport region ETR may include at least one of an electron blocking layer, an electron transport layer ETL, and an electron injection layer EIL. However, the embodiment is not limited thereto.

[0179] The electron transport region ETR may have a single layer formed using a single material, a single layer formed using a plurality of different materials, or a multi-layered structure having a plurality of layers formed using a plurality of different materials.

[0180] For example, the electron transport region ETR may have a single-layer structure of an electron injection layer EIL or an electron transport layer ETL or a single-layer structure formed using an electron injection material and an electron transport material. In addition, the electron transport region ETR may have a single-layer structure including a plurality of different materials or a structure of an electron transport layer ETL / electron injection layer EIL or a hole blocking layer / electron transport layer ETL / electron injection layer EIL stacked from an emission layer EML without limitation. The thickness of the electron transport region ETR may be, for example, about 100 Å. to about

[0181] The electron transport region ETR may be formed using various methods such as a vacuum deposition method, a spin coating method, a casting method, a Langmuir-Blodgett (LB) method, an inkjet printing method, a laser printing method, and a laser induced thermal imaging (LITI) method.

[0182] If the electron transport region ETR includes an electron transport layer ETL, the electron transport layer ETL may include tris(8-hydroxyquinoline)aluminum (Alq 3 ), 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 (Bp hen), 3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4-(naphthalene-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD), bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum (BAlq), bis(benzoquinoline-10-hydroxy)beryllium (Bebq 2 ), 9,10-di(naphthalene-2-yl)anthracene (ADN), and mixtures thereof, but the embodiment is not limited thereto.

[0183] If the electron transport region ETR includes an electron transport layer ETL, the thickness of the electron transport layer ETL may be about 500 Å. to about For example, about to about If the thickness of the electron transport layer ETL satisfies the above range, electron transport properties may be obtained to a satisfactory degree without significantly increasing driving voltage.

[0184] If the electron transport region ETR includes an electron injection layer EIL, the electron transport layer ETL may include LiF, lithium quinolate (LiQ), Li 2 O, BaO, NaCl, CsF, lanthanide metals (such as Yb) or metal halides (such as RbCl, RbI and KI). However, the embodiment is not limited thereto. The electron injection layer EIL can also be formed using a mixed material of an electron injection material and an insulating organic metal salt. The organic metal salt can be a material with an energy band gap of approximately 4 eV or greater. Specifically, the organic metal salt can include, for example, metal acetate, metal benzoate, metal acetoacetate, metal acetylacetonate or metal stearate.

[0185] If the electron transport region ETR includes an electron injection layer EIL, the thickness of the electron injection layer EIL may be about 500 Å. to about For example, about to about If the thickness of the electron injection layer EIL satisfies the above range, electron injection properties may be obtained to a satisfactory degree without causing a significant increase in driving voltage.

[0186] As described above, the electron transport region ETR may include a hole blocking layer. The hole blocking layer may include, for example, at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and 4,7-diphenyl-1,10-phenanthroline (Bphen). However, the embodiment is not limited thereto.

[0187] The second electrode EL2 is disposed on the electron transport region ETR. The second electrode EL2 has electrical conductivity. The second electrode EL2 may be formed using a metal alloy or a conductive compound. The second electrode EL2 may be a cathode. The second electrode EL2 may be a transmissive electrode, a transflective electrode, or a reflective electrode. If the second electrode EL2 is a transmissive electrode, the second electrode EL2 may be formed of a transparent metal oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), or the like.

[0188] If the second electrode EL2 is a transflective 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, a compound thereof, or a mixture thereof (e.g., a mixture of Ag and Mg). In addition, a multilayer structure including a reflective layer or a transflective layer formed using the above materials and a transparent conductive layer formed using indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), etc. may be formed.

[0189] Although not shown, the second electrode EL2 may be combined with the auxiliary electrode. If the second electrode EL2 is combined with the auxiliary electrode, the resistance of the second electrode EL2 may be reduced.

[0190] In the organic electroluminescent device 10, according to the voltages applied to the first electrode EL1 and the second electrode EL2, holes injected from the first electrode EL1 move to the emission layer EML via the hole transport region HTR, and electrons injected from the second electrode EL2 move to the emission layer EML via the electron transport region ETR. The electrons and holes are recombined in the emission layer EML to generate excitons, and light is emitted when the excitons drop from an excited state to a ground state.

[0191] If the organic electroluminescent device 10 is a top emission type, the first electrode EL1 may be a reflective electrode, and the second electrode EL2 may be a transmissive electrode or a transflective electrode. If the organic electroluminescent device 10 is a bottom emission type, the first electrode EL1 may be a transmissive electrode or a transflective electrode, and the second electrode EL2 may be a reflective electrode.

[0192] The organic electroluminescent device 10 according to the embodiment of the present invention uses the above-mentioned spiro compound as a material for an emission layer and can show improved emission efficiency and lifespan characteristics.

[0193] An embodiment of the present invention provides a spiro compound represented by the following Formula 1.

[0194] [Formula 1]

[0195]

[0196] In formula 1, R 1 and R 2 Each of them may independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycloalkyl group having 2 to 30 ring carbon atoms, or may combine with an adjacent group to form a ring.

[0197] In formula 1, Ar 1 It may be a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycloalkyl group having 2 to 30 ring carbon atoms.

[0198] In an embodiment, the substituted or unsubstituted Ar1 In the formula (a), one to eight substituents may be present, and in the case of two or more substituents, the substituents may be the same or different.

[0199] In the embodiment, in Ar 1 In the case of one or more substituents, Ar 1 The substituent may be a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, a substituted or unsubstituted cycloalkyl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycloalkyl group having 2 to 30 ring carbon atoms.

[0200] In formula 1, Ar 2 and Ar 3 Each may independently be a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms.

[0201] In formula 1, L 1 It may be a direct bond, a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring carbon atoms.

[0202] In an embodiment, L 1 Can be a direct key.

[0203] In Formula 1, a is an integer from 0 to 3, and l is an integer from 0 to 4. Meanwhile, if a is 2 or more, a plurality of R 1 The groups are the same or different, and if l is 2 or greater, then multiple R 2 The groups may be the same or different.

[0204] In formula 1, Z 1 and Z 2 A spiro connection of a ring compound represented by the following formula 2 is formed.

[0205] [Formula 2]

[0206]

[0207] In formula 2, X 1 Can be direct key, O, S, CR 5 R 6 、SiR 7 R 8 , BR 9 or NR 10 .

[0208] In formula 2, X 2 To X 5 Can be CR independently 11 R12 .

[0209] In formula 2, R 5 To R 12 Each may independently be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, a substituted or unsubstituted aryl group of 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group of 2 to 30 ring carbon atoms, or may combine with an adjacent group to form a ring.

[0210] With respect to the spiro compound of the embodiment represented by Formula 1, the same explanation of the spiro compound in the organic electroluminescent device of the embodiment will apply.

[0211] The spiro compound according to the embodiment may be any one selected from the compounds represented in Compound Group 1.

[0212] Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.The following Examples are merely illustrative to help understand the present invention, and the scope of the present invention is not limited thereto.

[0213] [Example]

[0214] 1. Synthesis of spiro compounds

[0215] (1) Synthesis Example 1-Synthesis of Compound 5

[0216]

[0217] 1) Synthesis of intermediate 5-1

[0218] Under nitrogen atmosphere, 10g (36mmol) 5-bromo-2-phenyl-1H-indole, 12g (72mmol) diphenylamine, 1.8g (1.5mmol) tetrakis (triphenylphosphine) palladium, 15g (108mmol) potassium carbonate, 50mL 1,4-dioxane, 50mL toluene and 20mL distilled water were added to the reactor and stirred for 12 hours at 120°C. After the reaction was completed, ethyl acetate and distilled water were used for extraction. The organic layer was concentrated under reduced pressure and then separated by column chromatography to obtain 4.4g (yield 34%) of intermediate 5-1.

[0219] 2) Synthesis of intermediate 5-2

[0220] 4 g (11 mmol) of the compound represented by intermediate 5-1, 4.7 g (15 mmol) of 2-bromo-4,6-diphenyl-1,3,5-triazine, 0.2 g (0.3 mmol) of tris (dibenzylideneacetone) dipalladium, 0.3 g (1 mmol) of tri-tert-butylphosphine tetrafluoroborate, 2 g (20 mmol) of sodium tert-butoxide and 20 mL of xylene were added and refluxed for 12 hours. After the reaction was completed, filtration was performed in a hot state under reduced pressure. After the solution was dried under reduced pressure, column chromatography was performed to obtain 3.4 g (yield 53%) of intermediate 5-2.

[0221] 3) Synthesis of intermediate 5-3

[0222] 3.4 g (5.8 mmol) of intermediate 5-2 and 100 mL of dichloromethane were added to the reactor, and then cooled to 0° C. 50 mL of a solution in which bromine was dissolved in dichloromethane was added dropwise thereto, and the temperature was raised to room temperature, and then stirring was performed for 2 hours. A sodium bicarbonate aqueous solution was added thereto, the organic layer was extracted and concentrated under reduced pressure, and separation was performed by column chromatography to obtain 3.2 g (yield 82%) of intermediate 5-3.

[0223] 4) Synthesis of Compound 5

[0224] Add 3.2g (4.8mmol) of intermediate 5-3 and 30mL of tetrahydrofuran, then cool to -78°C. Add 4mL (6mmol) of butyl lithium (1.6M hexane solution) dropwise thereto. After stirring for 2 hours at -78°C, 1.1g (6mmol) of 9-fluorenone is dissolved in 10mL of tetrahydrofuran, the solution is added dropwise, then the temperature is raised to room temperature and stirred for 2 hours. Add water, extract the organic layer with ethyl acetate, and then separate the organic layer with column chromatography to obtain 2.7g (molecular weight 753, 75%) of compound 5.

[0225] (2) Synthesis Example 2-Synthesis of Compound 13

[0226]

[0227] Compound 13 (molecular weight 843) was synthesized by the same method and process as that of Compound 5, except that diphenylamine was changed to N-phenyldibenzo[b,d]furan-4-amine in the reaction.

[0228] (3) Synthesis Example 3-Synthesis of Compound 21

[0229]

[0230] Compound 21 (molecular weight 865) was synthesized by the same method and process as that of Compound 5, except that diphenylamine was changed to bis(4-(tert-butyl)phenyl)amine in the reaction.

[0231] 2. Calculation of energy levels of spiro compounds

[0232] (Manufacturing of organic electroluminescent devices)

[0233] [Table 1]

[0234]

[0235] The S1 energy level and T1 energy level of the example compound and the comparative compound were calculated by the non-empirical molecular orbital method. Specifically, Gaussian09 of Gaussian Company was used to calculate using the function of B3LYP and the basis function of 6-31G*. The results are shown in Table 2 below. ΔEst means the absolute value of the difference between the singlet energy level and the triplet energy level.

[0236] [Table 2]

[0237] S1 energy level (eV) T1 energy level (eV) ΔEst Example Compound 5 2.418 2.373 0.045 Example Compound 13 2.424 2.378 0.046 Example Compound 21 2.326 2.311 0.015 Comparative compound Ref.1 2.919 2.508 0.411 Comparative compound Ref.2 2.867 2.497 0.370 Comparative compound Ref.3 2.937 2.502 0.435 Comparative compound Ref.4 3.428 2.532 0.896 Comparative compound Ref.5 2.424 2.404 0.020

[0238] Referring to the results of Table 2 above, all the example compounds showed small ΔEst values ​​and seemed suitable as materials for thermally activated delayed fluorescence, but the comparative compounds showed relatively large ΔEst values ​​of 0.2 eV or more and were not suitable as materials for thermally activated delayed fluorescence.

[0239] 3. Fabrication and evaluation of organic electroluminescent devices containing spiro compounds

[0240] (Manufacturing of organic electroluminescent devices)

[0241] The organic electroluminescent device of the embodiment including the spiro compound of the embodiment in the emission layer is manufactured by the following method. For example, the case where the emission layer of the organic electroluminescent device of the embodiment includes the spiro compound of the embodiment as a TADF dopant will be explained as an embodiment.

[0242] The organic compounds of the above-mentioned spiro compound 5, spiro compound 13 and spiro compound 21 are used as materials for the emission layer to manufacture the organic electroluminescent devices of Examples 1 to 3, and the comparative compounds Ref.1 to Ref.5 in Table 1 are used as materials for the emission layer to manufacture the organic electroluminescent devices of Comparative Examples 1 to 5.

[0243] As the anode, a 15Ω / cm 2 The ITO glass substrate was cut into a size of 50 mm × 50 mm × 0.7 mm, washed with isopropyl alcohol and pure water for 5 minutes respectively, then washed with ultrasonic waves, exposed to UV for 30 minutes and exposed to ozone. Then, the glass substrate was installed in a vacuum deposition device.

[0244] On the ITO anode, compound HT3 was vacuum deposited to deposit a hole transport layer having a thickness of 70 nm, and TCTA was deposited to a thickness of 10 nm to form a hole transport region.

[0245] Then, in order to form an emission layer, the spiro compound of the embodiment or the comparative compound and mCBP were co-deposited as a host at a weight ratio of 20% to form a On the emission layer, TPBi is used to form a layer having a thickness of A layer having a thickness of and using Liq to form Then, a layer with a thickness of 1000 to 10000 is formed using aluminum (Al) to form an electron transport region. The thickness of the second electrode is .

[0246] In the example, the hole transport region, the emission layer, the electron transport region, and the second electrode are formed using a vacuum deposition apparatus.

[0247] The efficiency and lifetime of the organic electroluminescent devices according to Examples 1 to 3 and Comparative Examples 1 to 5 were measured and shown in the following Table 3. In order to evaluate the light emitting properties of the organic electroluminescent devices thus manufactured, a C9920-11 light distribution measurement system of Hamamatsu Photonics Co. was used.

[0248] (Evaluation of properties of organic electroluminescent devices)

[0249] [Table 3]

[0250] Dopant color efficiency life Comparative Example 1 Ref.1 Sky blue 100％ 100％ Comparative Example 2 Ref.2 Sky blue 75％ 60％ Comparison Example 3 Ref.3 Sky blue 113％ 97％ Comparison Example 4 Ref.4 blue 60％ 85％ Comparative Example 5 Ref.5 green 170％ 122％ Example 1 Compound 5 green 210％ 135％ Example 2 Compound 13 green 231％ 158％ Example 3 Compound 21 green 227％ 140％

[0251] Referring to Table 3 above, Comparative Examples 1 to 4 are not suitable for emitting green light. In addition, it was confirmed that Comparative Examples 1 to 5 showed lower device efficiency and shorter lifespan when compared with Examples 1 to 3. Examples 1 to 3, in which the indenoindole derivative mainly includes an arylamine group combined with a core structure, are suitable as materials for thermally activated delayed fluorescence emitting green light, and thus are confirmed to contribute to high efficiency and long lifespan of the device.

[0252] Although preferred embodiments of the present invention have been described, it is understood that persons skilled in the corresponding technical field or persons having general knowledge in the corresponding technical field can variously change and modify the present invention within the scope and technical field of the present invention as claimed.

[0253] Therefore, the technical scope of the present invention should not be limited to the description in the detailed description of the specification but should be determined by the claims.

[0254] Industrial Applicability

[0255] In an organic electroluminescent device emitting green light, high efficiency and long lifetime are required. Therefore, the present invention relating to an organic electroluminescent device and a spiro compound has high industrial applicability.

Claims

1. An organic electroluminescent device, comprising: a first electrode; A hole transport region, disposed on the first electrode; An emission layer, disposed on the hole transport region; An electron transport region, disposed on the emission layer; as well as A second electrode is disposed on the electron transport region, wherein the emission layer comprises a spiro compound comprising an arylamine group and an indenoindole derivative, the spiro compound is used as a thermally activated delayed fluorescence dopant, and the emission layer emits green light, and Wherein, the spiro compound is represented by the following formula 3-1: [Formula 3-1] In formula 3-1, R1 and R2 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group or an unsubstituted alkyl group of 1 to 20 carbon atoms, Ar1 is a triazine group substituted with an aromatic group having 6 to 15 ring carbon atoms, Ar2 and Ar3 are each independently a phenyl group or a dibenzofuranyl group which is unsubstituted or substituted with at least one of a deuterium atom and an alkyl group having 1 to 20 carbon atoms, L1 is a direct connection key. a is an integer from 0 to 3, l is an integer from 0 to 4, R3 and R4 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group or an unsubstituted alkyl group of 1 to 20 carbon atoms, and m and n are each independently an integer from 0 to 4.

2. The organic electroluminescent device according to claim 1, wherein: The emission layer is a thermally activated delayed fluorescent emission layer.

3. The organic electroluminescent device according to claim 1, wherein: The spiro compound has an absolute value of a difference between a singlet energy level and a triplet energy level of 0.2 eV or less.

4. The organic electroluminescent device according to claim 1, wherein: The emitting layer also includes a body.

5. The organic electroluminescent device according to claim 1, wherein: The spiro compound represented by Formula 3-1 is any one of the compounds represented in the following Compound Group 1: [Compound Group 1] 6. A spiro compound, the spiro compound is represented by the following formula 3-1: [Formula 3-1] In formula 3-1, R1 and R2 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group or an unsubstituted alkyl group of 1 to 20 carbon atoms, Ar1 is a triazine group substituted with an aromatic group having 6 to 15 ring carbon atoms, Ar2 and Ar3 are each independently a phenyl group or a dibenzofuranyl group which is unsubstituted or substituted with at least one of a deuterium atom and an alkyl group having 1 to 20 carbon atoms, L1 is a direct connection key. a is an integer from 0 to 3, l is an integer from 0 to 4, R3 and R4 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group or an unsubstituted alkyl group of 1 to 20 carbon atoms, and m and n are each independently an integer from 0 to 4, in, The spiro compound is used as a thermally activated delayed fluorescence dopant.

7. The spiro compound according to claim 6, wherein The spiro compound represented by Formula 3-1 is any one of the compounds represented in the following Compound Group 1: [Compound Group 1]

Images