Fused polycyclic compound, organic electroluminescent device, and display apparatus

Abstract

Provided are a fused polycyclic compound, an organic electroluminescent device, and a display device of an embodiment. The fused polycyclic compound is represented by Formula 1. [Formula 1] wherein X, Y, R 11 to R 21 are the same as defined in the specification.

Description

[0001] This application is a divisional application of patent application No. 202010445865.4, filed on May 22, 2020, entitled "Organic Electroluminescent Device". Technical Field

[0002] This disclosure relates to an organic electroluminescent device and a fused polycyclic compound used in the organic electroluminescent device, and more specifically, to a fused polycyclic compound used as a luminescent material and an organic electroluminescent device comprising the fused polycyclic compound. Background Technology

[0003] Recently, there has been active development of organic electroluminescent display devices as image display devices. Unlike liquid crystal displays, organic electroluminescent display devices are so-called self-emissive display devices, in which holes and electrons injected from the first and second electrodes recombine in the emitting layer, and the luminescent material (including organic compounds) in the emitting layer emits light to achieve a display (e.g., an image).

[0004] When applying organic light-emitting devices to display devices, it is necessary to reduce the driving voltage and increase the emission efficiency and lifetime of organic light-emitting devices. The development of materials for organic light-emitting devices that stably meet the requirements is ongoing.

[0005] In particular, recently, in order to realize highly efficient organic electroluminescent devices, technologies related to phosphorescence emission (which utilizes triplet energy levels) or delayed fluorescence emission (which utilizes the phenomenon of triplet exciton collisions to generate singlet excitons (triplet-triplet annihilation, TTA)) are being developed, and materials utilizing thermally activated delayed fluorescence (TADF) that utilize the delayed fluorescence phenomenon are being developed. Summary of the Invention

[0006] One aspect of the embodiments of this disclosure is intended to provide an organic electroluminescent device with improved emission efficiency.

[0007] Another aspect of the embodiments of this disclosure aims to provide a fused polycyclic compound capable of improving the emission efficiency of organic electroluminescent devices.

[0008] According to an embodiment of the inventive concept, an organic electroluminescent device includes: a first electrode; a second electrode opposite to the first electrode; and a plurality of organic layers located between the first electrode and the second electrode. The first electrode and the second electrode each independently include at least one selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn, or each independently includes at least one selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, and LiF / Al. The plurality of organic layers comprises a complex of two or more of Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn and Zn, a mixture of two or more of Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn and Zn, or an oxide of Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn and Zn, wherein at least one of the plurality of organic layers comprises a fused polycyclic compound represented by the following Formula 1: Formula 1 .

[0009] In Equation 1, one of X and Y is chosen as BR. a Or P(=O)R b Another option chosen from X and Y is SiR. c R d And R a To R d Each of the following is independently a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group with 1 to 20 carbon atoms (substituted or unsubstituted), an aryl group with 6 to 60 carbon atoms forming a ring (substituted or unsubstituted), or a heteroaryl group with 2 to 60 carbon atoms forming a ring (substituted or unsubstituted), and R a To R d Any of the groups can (optionally) combine with an adjacent group to form a ring. R 11 To R 21 Each of these groups is independently composed of a hydrogen atom, a deuterium atom, a halogen atom, a boron group, a phosphonium oxide group, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, an substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, an substituted or unsubstituted aryl group with 6 to 60 cyclic carbon atoms, or a substituted or unsubstituted heteroaryl group with 2 to 60 cyclic carbon atoms, and R 11 To R 21 Any one of them can (optionally) combine with an adjacent group to form a ring.

[0010] In an embodiment, the plurality of organic layers may include: a hole transport region located on the first electrode; an emitter layer located on the hole transport region; and an electron transport region located on the emitter layer, wherein the emitter layer may include a fused polycyclic compound represented by Formula 1.

[0011] In one embodiment, the emitting layer can emit delayed fluorescence.

[0012] In an embodiment, the emission layer may be a delayed fluorescence emission layer comprising a host and a dopant, and the dopant may include a fused polycyclic compound represented by Formula 1.

[0013] In an embodiment, the emitter layer may include: a body having a first lowest triplet excitation level; a first dopant having a second lowest triplet excitation level lower than the first lowest triplet excitation level; and a second dopant having a third lowest triplet excitation level lower than the second lowest triplet excitation level, wherein the first dopant may include a fused polycyclic compound represented by Formula 1.

[0014] In the embodiments, the first dopant may be a delayed fluorescence dopant, and the second dopant may be a fluorescent dopant.

[0015] In the embodiments, the fused polycyclic compound represented by Formula 1 can be represented by any one of the following Formulas 1-1 to 1-3: Equation 1-1

[0016] Formula 1-2

[0017] Formula 1-3 .

[0018] In equations 1-1 to 1-3, R 11 To R 21 R c and R d They are the same as those defined in combination 1, and X1, X 11 X 12 and X 13 Each is independently either B or P (=O). R n and R m Each of these groups is independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, a substituted or unsubstituted aryl group with 6 to 60 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group with 2 to 60 ring-forming carbon atoms, and R n and R mAny one of them can (optionally) combine with an adjacent group to form a ring, where n is an integer from 0 to 5 and m is an integer from 0 to 4. R aa and R bb Each of the following is independently a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group with 1 to 20 carbon atoms (substituted or unsubstituted), an aryl group with 6 to 60 carbon atoms forming a ring (substituted or unsubstituted), or a heteroaryl group with 2 to 60 carbon atoms forming a ring (substituted or unsubstituted), and R aa and R bb Any of the groups may (optionally) combine with an adjacent group to form a ring, and Ar is a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group with 1 to 20 carbon atoms that are substituted or unsubstituted, an aryl group with 6 to 60 carbon atoms that are substituted or unsubstituted, or a heteroaryl group with 2 to 60 carbon atoms that are substituted or unsubstituted.

[0019] In the embodiment, X1 in Equation 1-1 can be P (=O), and n can be 0.

[0020] In the embodiment, X in Equation 1-2 11 and X 12 They can be the same.

[0021] In the embodiments, in Equations 1-2, in X 11 and X 12 When both are B, R aa and R bb They can all be independently substituted or unsubstituted phenyl groups, in X 11 and X 12 When both are P (=O), R aa and R bb Each can be an unsubstituted phenyl group independently.

[0022] In the embodiment, R c and R d Each can be an unsubstituted phenyl group independently.

[0023] According to an embodiment of the inventive concept, a fused polycyclic compound represented by Formula 1 above is provided. Attached Figure Description

[0024] The accompanying drawings are included to provide a further understanding of the inventive concept, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the inventive concept and, together with the description, serve to explain the principles of the inventive concept. In the drawings: Figure 1 This is a schematic cross-sectional view of an organic electroluminescent device according to an embodiment of the inventive concept; Figure 2This is a schematic cross-sectional view of an organic electroluminescent device according to an embodiment of the inventive concept; Figure 3 This is a schematic cross-sectional view of an organic electroluminescent device according to an embodiment of the inventive concept; and Figure 4 This is a schematic cross-sectional view of an organic electroluminescent device according to an embodiment of the inventive concept. Detailed Implementation

[0025] The inventive concept can have various suitable modifications and can be implemented in different forms, and exemplary embodiments will be explained in more detail with reference to the accompanying drawings. However, the inventive concept can be embodied in different forms and should not be construed as being limited to the embodiments set forth herein. Rather, all modifications, equivalents, and substitutions included within the spirit and scope of the inventive concept should be incorporated into the inventive concept.

[0026] It will be understood that when an element is referred to as being "on" another element, "connected to" or "combined to" another element, the element may be directly on, directly connected to or directly combined with the other element, or there may be an intermediate element present.

[0027] The same reference numerals always refer to the same elements. Furthermore, in the accompanying drawings, the thickness, proportions, and dimensions of the constituent elements are exaggerated to effectively explain the technical content.

[0028] The term "and / or" includes one or more combinations that can be defined by the relevant elements.

[0029] 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 used only to distinguish one element from another. Thus, without departing from the teachings of this disclosure, a first element may be named a second element. Similarly, a second element may be named a first element. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form.

[0030] Additionally, the terms "below," "under," "above," and "over" are used to explain the relationships between the elements shown in the accompanying drawings. These terms are relative concepts and are interpreted based on the directions shown in the drawings.

[0031] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will also be understood that terms (such as those defined in a general dictionary) shall be interpreted as having the same meaning as they have in the context of the relevant field and shall not be interpreted in an idealized or overly formalized sense, unless expressly defined herein.

[0032] It will also be understood that when the terms “comprising” and variations thereof and / or “including” and variations thereof are used in this specification, they indicate the presence of the stated features, figures, steps, operations, elements, components or combinations thereof, but do not exclude the presence or addition of one or more other features, figures, steps, operations, elements, components or combinations thereof.

[0033] The organic electroluminescent device according to the inventive concept will be explained in more detail below with reference to the accompanying drawings.

[0034] Figures 1 to 4 This is a schematic cross-sectional view illustrating an organic electroluminescent device according to an exemplary embodiment of the inventive concept. (Refer to...) Figures 1 to 4 In the organic electroluminescent device 10 according to the embodiment, a first electrode EL1 and a second electrode EL2 are disposed opposite to each other, and a plurality of organic layers may be disposed between the first electrode EL1 and the second electrode EL2. The plurality of organic layers may include a hole transport region (HTR), an emitter layer (EML), and an electron transport region (ETR). That is, the organic electroluminescent device 10 of the embodiment may include (e.g., in the order stated) a first electrode EL1, a hole transport region (HTR), an emitter layer (EML), an electron transport region (ETR), and a second electrode EL2 stacked on top of each other. A capping layer (CPL) may be further disposed on the second electrode EL2 (see [link to embodiment]). Figure 4 ).

[0035] The organic electroluminescent device 10 of the embodiment may include, in at least one of the plurality of organic layers disposed between the first electrode EL1 and the second electrode EL2, the fused polycyclic compound of the embodiment, which will be explained in more detail later. For example, the organic electroluminescent device 10 of the embodiment may include, in the emitter layer EML disposed between the first electrode EL1 and the second electrode EL2, the fused polycyclic compound of the embodiment, which will be explained in more detail later. However, the embodiments of the inventive concept are not limited thereto. The organic electroluminescent device 10 of the embodiment may include, in at least one organic layer other than the emitter layer EML disposed between the first electrode EL1 and the second electrode EL2, the fused polycyclic compound of the embodiment, which will be explained in more detail later, in the hole transport region HTR and the electron transport region ETR, or in the capping layer CPL disposed on the second electrode EL2, the fused polycyclic compound of the embodiment, which will be explained in more detail later.

[0036] At the same time, when with Figure 1 In comparison, Figure 2 A cross-sectional view of an organic electroluminescent device 10 is shown, 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. Additionally, when compared with... Figure 1 In comparison, Figure 3 A cross-sectional view of an organic electroluminescent device 10 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. When compared with... Figure 1 In comparison, Figure 4 A cross-sectional view of an organic electroluminescent device 10, including a capping layer CPL disposed on a second electrode EL2, is shown.

[0037] In the following explanation of the organic electroluminescent device 10 of the embodiments, the emitter layer EML is interpreted as including the fused polycyclic compound according to the embodiments, which will be explained in more detail later, but the embodiments of the inventive concept are not limited thereto. The fused polycyclic compound according to the embodiments, which will be explained in more detail later, may be included in the hole transport region HTR, the electron transport region ETR, or the capping layer CPL.

[0038] The first electrode EL1 is conductive. For example, the first electrode EL1 may include at least one selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn, or may include at least one selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn. The first electrode EL1 can be a composite of two or more of the following: a mixture of two or more of Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn; or an oxide of Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn. The first electrode EL1 can be formed using a metal alloy and / or a conductive compound. The first electrode EL1 can be an anode. The first electrode EL1 can be a pixel electrode. The first electrode EL1 can be a transmission electrode, a transmission-reflection electrode, or a reflection electrode. If the first electrode EL1 is a transmission electrode, it can be formed using 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 or reflective electrode, it may comprise Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, their composites, or mixtures thereof (e.g., a mixture of Ag and Mg). Furthermore, the first electrode EL1 may have a structure comprising multiple layers, including a reflective or transmissive layer formed using the aforementioned materials and a transmissive conductive layer formed using ITO, IZO, ZnO, and / or ITZO. For example, the first electrode EL1 may comprise a three-layer structure of ITO / Ag / ITO. However, embodiments of the inventive concept are not limited thereto. The thickness of the first electrode EL1 may be from about 1,000 Å to about 10,000 Å, for example, from about 1,000 Å to about 3,000 Å.

[0039] A hole transport region (HTR) is disposed on the first electrode EL1. The hole transport region (HTR) may include a hole injection layer (HIL), a hole transport layer (HTL), a hole buffer layer, and / or an electron blocking layer (EBL). The thickness of the hole transport region (HTR) may be from approximately 50 Å to approximately 1,500 Å.

[0040] The hole transport region (HTR) can have: a single layer formed using a single material; a single layer formed using multiple different materials; or a multi-layer structure including multiple layers formed using multiple different materials.

[0041] For example, the hole transport region HTR can have a single-layer structure of a hole injection layer HIL or a hole transport layer HTL, or it can have a single-layer structure formed using a hole injection material and a hole transport material. Alternatively, the hole transport region HTR can have a single-layer structure formed using a variety of different materials, or it can have a structure of hole injection layer HIL / hole transport layer HTL, hole injection layer HIL / hole transport layer HTL / hole buffer layer, hole injection layer HIL / hole buffer layer, hole transport layer HTL / hole buffer layer, or hole injection layer HIL / hole transport layer HTL / electron blocking layer EBL stacked from the first electrode EL1, but this disclosure is not limited thereto.

[0042] Hole transport regions (HTRs) can be formed using a variety of suitable methods such as vacuum deposition, spin coating, casting, Langmuir-Blodget (LB) methods, inkjet printing, laser printing, and / or laser-induced thermal imaging (LITI).

[0043] Hole injection layer HIL can include, for example, phthalocyanine compounds (such as copper phthalocyanine), (N 1 N 1' -([1,1'-biphenyl]-4,4'-diyl)bis(N) 1 -Phenyl-N 4 N 4 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-styrene sulfonate) (PANI / PSS), N,N'-di(naphthyl-1-yl)-N,N'-diphenyl-benzidine (NPB), N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPD), triphenylamine-containing polyether ketone (TPAPEK), 4-isopropyl-4'-methyldiphenyliodonium [tetra(pentafluorophenyl)borate] and / or dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexaonitrile (HAT-CN).

[0044] Hole transport layers (HTLs) can include, for example, carbazole derivatives (such as N-phenylcarbazole, 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”-tris(N-carbazolyl)triphenylamine (TCTA)), and N,N'-bis(1-naphthyl)-N,N'-diphenyl Examples of such products include 4,4'-cyclohexyl-bis[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), and 9-(4-tert-butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole (CzSi).

[0045] The thickness of the hole transport region (HTR) can be from about 100 Å to about 10,000 Å, for example, from about 100 Å to about 5,000 Å. The thickness of the hole injection layer (HIL) can be, for example, from about 30 Å to about 1,000 Å, and the thickness of the hole transport layer (HTL) can be from about 30 Å to about 1,000 Å. For example, the thickness of the electron blocking layer (EBL) can be from about 10 Å to about 1,000 Å. 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) meet the above ranges, satisfactory hole transport performance can be achieved without significantly increasing the driving voltage.

[0046] In addition to the materials described above, the hole transport region (HTR) may also include a charge-generating material to increase conductivity. The charge-generating material may be uniformly or non-uniformly dispersed in the hole transport region (HTR). The charge-generating material may be, for example, a p-doper. The p-doper may be one of quinone derivatives, metal oxides, and cyano-containing compounds, but this disclosure is not limited thereto. For example, non-limiting examples of p-dopers may include quinone derivatives (such as tetracyanoquinone dimethyl (TCNQ) and / or 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinone dimethyl (F4-TCNQ)) and / or metal oxides (such as tungsten oxide and / or molybdenum oxide), but this disclosure is not limited thereto.

[0047] As described above, in addition to the hole injection layer (HIL) and the hole transport layer (HTL), the hole transport region (HTR) may also include a hole buffer layer and / or an electron blocking layer (EBL). The hole buffer layer can improve luminous efficiency by compensating for the optical resonant distance based on the wavelength of light emitted from the emitter layer (EML). Materials that can be included in the hole transport region (HTR) can be used as materials included in the hole buffer layer. The electron blocking layer (EBL) is a layer that prevents or substantially prevents electrons from being injected from the electron transport region (ETR) into the hole transport region (HTR).

[0048] The emitter layer (EML) is disposed on the hole transport region (HTR). The emitter layer (EML) may have a thickness of, for example, from about 100 Å to about 1,000 Å or from about 100 Å to about 300 Å. The emitter layer (EML) may be: a single layer formed using a single material; a single layer formed using multiple different materials; or a multilayer structure comprising multiple layers formed using multiple different materials.

[0049] In the organic electroluminescent device 10 of the embodiment, the emitting layer EML may include the fused polycyclic compound of the embodiment.

[0050] In this specification, the term "substituted or unsubstituted" refers to an unsubstituted group or a group substituted with at least one substituent selected from the group consisting of deuterium, halogen, cyano, nitro, amino, silyl, oxy group (or "oxy-containing"), thiol, sulfinyl, sulfonyl, carbonyl, boron, phosphine oxide, phosphine sulfide, alkyl, alkenyl, alkoxy, cycloalkyl, aryl, and heterocyclic groups. Additionally, each of the exemplary substituents may be substituted or unsubstituted. For example, biphenyl can be interpreted as aryl or a phenyl group substituted with a phenyl group.

[0051] In this specification, the term "forming a ring via bonding with an adjacent group" can refer to the formation of a substituted or unsubstituted hydrocarbon ring or a substituted or unsubstituted heterocycle via bonding with an adjacent group. Hydrocarbon rings include aliphatic hydrocarbon rings and aromatic hydrocarbon rings. Heterocycles include aliphatic heterocycles and aromatic heterocycles. The ring formed by bonding with an adjacent group can be a monocyclic or polycyclic ring. Furthermore, a ring formed by bonding with an adjacent group can bond with another ring to form a spirostructure.

[0052] In the specification, the term "adjacent group" can refer to a substituent that directly substitutes for an atom of a corresponding substituent, another substituent that substitutes for an atom of a corresponding substituent, or a substituent located spatially closest to 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-diethylcyclopentane, the two ethyl groups can be interpreted as "adjacent groups" to each other.

[0053] In the specification, the halogen atom can be a fluorine atom, a chlorine atom, a bromine atom, and / or an iodine atom.

[0054] In the specification, the alkyl group can be a straight-chain alkyl group, a branched alkyl group, or a cyclic alkyl group. The number of carbon atoms in the alkyl group can be 1 to 50, 1 to 30, 1 to 20, 1 to 10, or 1 to 6. Examples of alkyl groups 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, 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-butyloctyl, 2-hexyloctyl, 3,7-dimethyloctyl, cyclooctyl, n-nonyl, n-decyl, adamantyl, 2-ethyldecyl, 2-butyldecyl, 2 - Hexyldecyl, 2-octyldecyl, undecyl, dodecyl, 2-ethyldodecyl, 2-butyldodecyl, 2-hexyldodecyl, 2-octyldodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, 2-ethylhexadecyl, 2-butylhexadecyl, 2-hexylhexadecyl, 2-octylhexadecyl, heptadecanyl, octadecyl, nonadecanyl, eicosyl, 2-ethyleicosyl, 2-butyleicosyl, 2-hexyleicosyl, 2-octyleicosyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecanyl, hexadecyl, octadecyl, nonadecanyl, triadecyl, etc., but this disclosure is not limited thereto.

[0055] In this specification, hydrocarbon rings include aliphatic hydrocarbon rings and aromatic hydrocarbon rings. Heterocycles include aliphatic heterocycles and aromatic heterocycles. Hydrocarbon rings and heterocycles can be monocyclic or polycyclic.

[0056] In the specification, the hydrocarbon ring may be 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 carbon atoms in the forming ring of the hydrocarbon ring may be from 5 to 60.

[0057] In the specification, the heterocyclic group can be an optional functional group or substituent derived from a heterocycle that includes at least one heteroatom as a cyclizing element. The number of carbon atoms in the forming ring of the heterocyclic group can be from 2 to 60.

[0058] In this specification, aryl refers to an optional functional group or substituent derived from an aromatic hydrocarbon ring. The aryl group can be monocyclic or polycyclic. The number of carbon atoms forming the ring in the aryl group can be 6 to 30, 6 to 20, or 6 to 15. Examples of aryl groups may include phenyl, naphthyl, fluorenyl, anthraceneyl, phenanthryl, biphenyl, terphenyl, tetraphenyl, pentaphenyl, hexaphenyl, benzo[9,10]phenanthryl, pyrene, benzofluoranthracene, phenyl, etc., but this disclosure is not limited thereto.

[0059] In this specification, the fluorene group may be substituted, and two substituents may combine with each other to form a spirostructure. Examples of substituted fluorene groups are given below. However, embodiments of the inventive concept are not limited thereto.

[0060]

[0061] In the specification, a heteroaryl group can be a heteroaryl group comprising one or more heteroatoms selected from B, O, N, P, Si, and S. If a heteroaryl group comprises two or more heteroatoms, the two or more heteroatoms can be the same or different. A heteroaryl group can be a monocyclic heteroaryl group or a polycyclic heteroaryl group. The ring forming the heteroaryl group can have 2 to 30, 2 to 20, or 2 to 10 carbon atoms. Examples of heteroaryl groups may include thienyl, furanyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, oxadiazolyl, triazolyl, pyridyl, bipyridyl, pyrimidinyl, triazinyl, acridineyl, pyridazinyl, quinolinyl, quinazolinyl, quinoxazinyl, phenothiazinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolinyl, indolyl, carbazole, N-arylcarbazole, N-heteroarylcarbazole, N-alkylcarbazole, benzoxazolyl, benzimidazolyl, benzothiazolyl, benzocarbazole, benzothiazolyl, benzothiaphenyl, dibenzothiaphenyl, thiaphenothiaphenyl, benzofuranyl, phenanthrolyl, isoxazolyl, thiadiazolyl, phenothiazinyl, dibenzothiaryl, dibenzofuranyl, etc., but this disclosure is not limited thereto.

[0062] In the specification, silane includes alkylsilane and arylsilane. Examples of silane may include trimethylsilane, triethylsilane, tert-butyldimethylsilane, propyldimethylsilane, triphenylsilane, diphenylsilane, phenylsilane, etc. However, embodiments of the inventive concept are not limited thereto.

[0063] In this specification, the boron group includes alkylboron group and arylboron group. Examples of boron groups include trimethylboron group, triethylboron group, tert-butyldimethylboron group, triphenylboron group, diphenylboron group, phenylboron group, etc., but this disclosure is not limited thereto.

[0064] In this specification, the number of carbon atoms in the amino group (or amino group) is not specifically limited, and can be from 1 to 30. The amino group can include alkylamino and arylamino groups. Examples of amino groups include methylamino, dimethylamino, phenylamino, naphthylamino, 9-methyl-anthraylamino, triphenylamino, etc., but this disclosure is not limited thereto.

[0065] In this specification, a hydrocarbon ring refers to an optional functional group or substituent derived from an aliphatic hydrocarbon ring. A hydrocarbon ring can be a saturated hydrocarbon ring with 5 to 20 carbon atoms forming the ring.

[0066] In the specification, the heterocyclic group may include one or more heteroatoms selected from B, O, N, P, Si, and S. If the heterocyclic group includes two or more heteroatoms, the two or more heteroatoms may be the same or different. The heterocyclic group may be a monocyclic or polycyclic heterocyclic group and has the concept of including (for example, including) a heteroaryl group. The ring forming the heterocyclic group may have 2 to 30, 2 to 20, or 2 to 10 carbon atoms.

[0067] The fused polycyclic compound of the embodiment can be represented by the following formula 1: Formula 1 .

[0068] In Equation 1, one of X and Y is chosen as BR. a Or P(=O)R b And the other one chosen from X and Y is SiR. c R d For example, in the fused polycyclic compound represented by Formula 1 in the embodiments, either X or Y can be BR. a And another could be SiR c R d Alternatively, either X or Y can be P(=O)R. b And another could be SiR c R d In other words, the fused polycyclic compounds in the embodiments may need to include Si as a heteroatom.

[0069] In Equation 1, R a To R d Each of the following can be independently a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group with 1 to 20 carbon atoms (substituted or unsubstituted), an aryl group with 6 to 60 carbon atoms forming a ring (substituted or unsubstituted), or a heteroaryl group with 2 to 60 carbon atoms forming a ring (substituted or unsubstituted), and R a To R d Any one of them can (optionally) combine with an adjacent group to form a ring.

[0070] For example, in Equation 1, R a and R b Each of these can be an aryl group consisting of 6 to 60 substituted or unsubstituted carbon atoms forming a ring. In one embodiment, R a and R b Each of these can be an aryl group consisting of 6 to 60 cyclic carbon atoms substituted with an alkyl or aryl group, or an unsubstituted aryl group consisting of 6 to 60 cyclic carbon atoms. In Formula 1, R a and R b Each of them can be a substituted or unsubstituted phenyl group.

[0071] In Equation 1, R c and R d They can be the same. For example, in Equation 1, R c and R d Both can be independently substituted or unsubstituted phenyl groups. In one embodiment, R c and R d All of them can be unsubstituted phenyl groups.

[0072] Additionally, in Equation 1, R 11 To R 21 Each of these groups can independently be a hydrogen atom, a deuterium atom, a halogen atom, a boron group, a phosphonium oxide group, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, an substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, a substituted or unsubstituted aryl group with 6 to 60 cyclic carbon atoms, or a substituted or unsubstituted heteroaryl group with 2 to 60 cyclic carbon atoms, and R 11 To R 21 Any one of them can (optionally) combine with an adjacent group to form a ring (i.e., R). 11 To R 21 Each group can independently and optionally combine with adjacent groups to form a ring.

[0073] For example, in Equation 1, R 11 To R 21 Each group can independently be a hydrogen atom, an arylamine group, an aryl group with 6 to 30 substituted or unsubstituted carbon atoms forming a ring, or a heteroaryl group with 2 to 30 substituted or unsubstituted carbon atoms forming a ring, and R 11 To R 21 Any one of them can (optionally) combine with an adjacent group to form a hydrocarbon ring or heterocycle.

[0074] In Equation 1, R 11 To R 21 It can be an electron donor substituent represented by an arylamine group, or an electron acceptor substituent represented by a heteroaryl group including N (nitrogen atom) as a cyclizing element, an aryl group substituted with an aryl group, or an unsubstituted aryl group.

[0075] Compared to prior art DABNA series polycyclic compounds, which include N and B as heteroatoms forming the ring, the fused polycyclic compounds of the embodiments must include Si as a cyclic heteroatom forming the corresponding fused ring in the core, and can exhibit bulkiness and improved rigidity. Furthermore, the fused polycyclic compounds of the embodiments exhibit multiple resonances through the multiple aromatic rings forming the fused ring, and can separate HOMO and LUMO states within a molecule (e.g., easily separable), and are therefore suitable for use as delayed fluorescence emission materials. Additionally, compared to prior art DABNA series polycyclic compounds, the fused polycyclic compounds of the embodiments include Si as a cyclic heteroatom and exhibit increased rigidity, thus reducing the τ value (delayed emission time) and exhibiting an increased reverse intersystem crossover (RISC) rate and improved lifetime effect (e.g., improved lifetime). Furthermore, because the fused polycyclic compounds of the embodiments have a high lowest triplet excitation level (T1 level), the emission efficiency of organic electroluminescent devices can be further improved when used as delayed fluorescence emission materials.

[0076] The fused polycyclic compound represented by Formula 1 can be represented by any one of Formulas 1-1 to 1-3 below: Equation 1-1

[0077] Formula 1-2

[0078] Formula 1-3 .

[0079] In Equation 1-1, X1 can be B or P (=O). In Equation 1-1, R n It can be a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, a substituted or unsubstituted aryl group with 6 to 60 carbon atoms forming a ring, or a substituted or unsubstituted heteroaryl group with 2 to 60 carbon atoms forming a ring, and can (optionally) combine with adjacent groups to form a ring (i.e., R). n It can optionally combine with adjacent groups to form a ring.

[0080] n can be an integer from 0 to 5. Furthermore, in Equation 1-1, when n is 0, the phenyl group bonded to X1 can be an unsubstituted phenyl group. Additionally, when n is 5 and all R... n When the atom is hydrogen, the phenyl group bonded to X1 can be an unsubstituted phenyl group. In Equation 1-1, when n is an integer of 2 or greater, multiple R... n They can be the same, or multiple Rs.n At least one of them can be different.

[0081] In Formula 1-1, when X1 is B, the phenyl group bonded to X1 can be either substituted or unsubstituted. For example, R n It can be a hydrogen atom or a methyl group. Additionally, in Formula 1-1, when X1 is P (=O), the phenyl group bonded to X1 can be an unsubstituted phenyl group. For example, in Formula 1-1, when X1 is P (=O), n can be 0.

[0082] In Equation 1-2, X 11 and X 12 Each can be independently B or P (=O). For example, X 11 and X 12 They can be the same. In one embodiment, X 11 and X 12 Both can be B or X 11 and X 12 Both can be P (=O).

[0083] In equation 1-2, R aa and R bb Each of the following can be independently a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group with 1 to 20 carbon atoms (substituted or unsubstituted), an aryl group with 6 to 60 carbon atoms forming a ring (substituted or unsubstituted), or a heteroaryl group with 2 to 60 carbon atoms forming a ring (substituted or unsubstituted), and R aa and R bb Any one of them can (optionally) combine with an adjacent group to form a ring (i.e., R). aa and R bb Each group can independently and optionally combine with adjacent groups to form a ring.

[0084] For example, R aa and R bb Each group can be an aryl group, consisting of 6 to 30 substituted or unsubstituted carbon atoms forming a ring. In one embodiment, R aa and R bb They can all be independently substituted or unsubstituted phenyl groups. In formulas 1-2, when X 11 and X 12 When both are B, R aa and R bb They can all be independently substituted or unsubstituted phenyl groups, when X 11 and X 12 When both are P (=O), R aa and R bb Each can be an unsubstituted phenyl group independently.

[0085] In equations 1-3, X 13It can be B or P (=O). In equation 1-3, R m It can be a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, a substituted or unsubstituted aryl group with 6 to 60 carbon atoms forming a ring, or a substituted or unsubstituted heteroaryl group with 2 to 60 carbon atoms forming a ring, and can (optionally) combine with adjacent groups to form a ring (i.e., R). m It can combine with adjacent groups to form a ring.

[0086] m can be an integer from 0 to 4. In equations 1-3, when m is an integer of 2 or greater, multiple R... m They can be the same, or multiple Rs. m At least one of them can be different.

[0087] For example, in equation 1-3, R m It can be a substituted or unsubstituted aryl amino group, a substituted or unsubstituted aryl group with 6 to 30 ring-forming carbon atoms, a substituted or unsubstituted heteroaryl group with 2 to 30 ring-forming carbon atoms, and can (optionally) combine with adjacent groups to form a substituted or unsubstituted fluorenyl group.

[0088] In Formulas 1-3, Ar can be a hydrogen atom, a deuterium atom, a halogen atom, an alkyl group with 1 to 20 carbon atoms (substituted or unsubstituted), an aryl group with 6 to 60 carbon atoms forming a ring (substituted or unsubstituted), or a heteroaryl group with 2 to 60 carbon atoms forming a ring (substituted or unsubstituted). For example, Ar can be an aryl group with 6 to 30 carbon atoms forming a ring (substituted or unsubstituted).

[0089] Furthermore, in Equations 1-1 to 1-3, the same interpretations as in Equation 1 can be applied to R. 11 To R 21 R c and R d .

[0090] The fused polycyclic compound of the embodiments may be any of the compounds selected from the compounds represented in group 1 below. The organic electroluminescent device 10 of the embodiments may include at least one fused polycyclic compound selected from the compounds represented in group 1 in the emitting layer EML.

[0091] Compound group 1

[0092]

[0093]

[0094]

[0095]

[0096] The fused polycyclic compound represented by Formula 1 in the embodiments can be a thermally activated delayed fluorescence emission material. Additionally, the fused polycyclic compound represented by Formula 1 in the embodiments can be the difference (ΔE) between the lowest triplet excitation energy level (T1 level) and the lowest singlet excitation energy level (S1 level) having an energy of about 0.2 eV or less (e.g., about 0.1 eV or less). ST Thermally activated delayed fluorescence dopants. For example, the ΔE of the fused polycyclic compound represented by Formula 1 in the examples. ST It can be about 0.01 eV or less.

[0097] The fused polycyclic compound represented by Formula 1 in the embodiments can be a luminescent material having a central emission wavelength in the wavelength region of about 430 nm to about 490 nm. For example, the fused polycyclic compound represented by Formula 1 in the embodiments can be a blue thermally activated delayed fluorescence (TADF) dopant. However, the embodiments of the inventive concept are not limited thereto. When using the fused polycyclic compound of the embodiments as a luminescent material, the fused polycyclic compound can be used as a dopant material that emits light in various suitable wavelength regions, such as a red emission dopant and / or a green emission dopant.

[0098] In the organic electroluminescent device 10 of the embodiment, the emitting layer EML can emit delayed fluorescence. For example, the emitting layer EML can emit thermally activated delayed fluorescence (TADF).

[0099] Additionally, the organic electroluminescent device 10 can emit blue light. For example, the emitting layer EML of the organic electroluminescent device 10 in the embodiment can emit blue light in a wavelength region of about 490 nm or larger. However, the embodiments of the inventive concept are not limited to this, and the emitting layer EML can emit green or red light.

[0100] Furthermore, in one embodiment, the organic electroluminescent device 10 of the embodiment may include multiple emission layers. The multiple emission layers may be stacked and disposed on top of each other. For example, the organic electroluminescent device 10 including multiple emission layers can emit white light. The organic electroluminescent device 10 including multiple emission layers may be an organic electroluminescent device having a series structure. When the organic electroluminescent device 10 includes multiple emission layers, at least one emission layer EML may include the fused polycyclic compound of the embodiment.

[0101] In embodiments, the emitter layer EML includes a host and a dopant, and may include a fused polycyclic compound as a dopant. For example, in the organic electroluminescent device 10 of the embodiments, the emitter layer EML may include a host for emitting delayed fluorescence and a dopant for emitting delayed fluorescence, and may include a fused polycyclic compound as a dopant for emitting delayed fluorescence. The emitter layer EML may include at least one selected from the fused polycyclic compounds represented in compound group 1 as a thermally activated delayed fluorescence dopant.

[0102] In embodiments, the emission layer EML may be a delayed fluorescence emission layer, and the emission layer EML may include a suitable (e.g., known) host material and the aforementioned fused polycyclic compound. For example, in embodiments, the fused polycyclic compound may be used as a TADF dopant.

[0103] Furthermore, in embodiments, the emitter layer EML may include a suitable (e.g., known) host material. For example, in embodiments, the emitter layer EML may include tris(8-hydroxyquinoline)aluminum (Alq3), 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP), poly(N-vinylcarbazole) (PVK), 9,10-bis(naphthyl-2-yl)anthracene (ADN), 4,4',4”-tris(carbazolyl-9-yl)triphenylamine (TCTA), 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBi), 3-tert-butyl-9,10-bis(naphthyl-2-yl)anthracene (TBADN), stilbeneyl arylene (DSA), 4,4'-bis(9-carbazolyl)-2,2'-dimethyl-biphenyl (CDBP), 2-methyl-9,10-bis(naphthyl-2-yl)triphenylamine (DAP), etc. The following are examples of host materials: 1,4-bis(triphenylsilyl)benzene (MADN), bis[2-(diphenylphosphino)phenyl]ether oxide (DPEPO), hexaphenylcyclotriphosphazene (CP1), 1,4-bis(triphenylsilyl)benzene (UGH2), hexaphenylcyclotrisiloxane (DPSiO3), octaphenylcyclotetrasiloxane (DPSiO4), 2,8-bis(diphenylphosphino)dibenzo[b,d]furan (PPF), 3,3'-bis(N-carbazolyl)-1,1'-biphenyl (mCBP), 1,3-bis(N-carbazolyl)benzene (mCP), etc. However, embodiments of the inventive concept are not limited thereto. Any suitable (e.g., known) host material other than the proposed host material may be included to emit delayed fluorescence.

[0104] Additionally, in the organic electroluminescent device 10 of the embodiment, the emission layer EML may also include suitable (e.g., known) dopant materials. In the embodiment, the emission layer EML may include styrene derivatives (e.g., 1,4-bis[2-(3-N-ethylcarbazolyl)vinyl]benzene (BCzVB), 4-(di-p-tolylamino)-4'-[(di-p-tolylamino)styrene]stilbene (DPAVB) and / or N-(4-((E)-2-(6-((E)-4-(diphenylamino)styrene)naphth-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-dipyrenebenzene, 1,4-bis(N,N-diphenylamino)pyrene) as dopant materials.

[0105] Additionally, in embodiments, the emitter layer EML may include two dopant materials having different lowest triplet excitation energy levels (T1 levels). In the organic electroluminescent device 10 of the embodiment, the emitter layer EML may include a host having a first lowest triplet excitation energy level, a first dopant having a second lowest triplet excitation energy level lower than the first lowest triplet excitation energy level, and a second dopant having a third lowest triplet excitation energy level lower than the second lowest triplet excitation energy level. In embodiments, the emitter layer EML may include the aforementioned fused polycyclic compound as the first dopant.

[0106] In the organic electroluminescent device 10 of the embodiment (which includes a host, a first dopant, and a second dopant in the emitter layer EML), the first dopant may be a delayed fluorescence dopant, and the second dopant may be a fluorescent dopant. Additionally, in the organic electroluminescent device 10 of the embodiment, the fused polycyclic compound represented by Formula 1 may serve as an auxiliary dopant.

[0107] For example, when the emitting layer EML of the organic electroluminescent device 10 of the embodiment includes multiple dopants, the emitting layer EML may include the fused polycyclic compound of the embodiment as a first dopant and the above-mentioned suitable (e.g., known) dopant material as a second dopant. For example, when the emitting layer EML emits blue light, the emitting layer EML may also include any one selected from the group consisting of spiro-DPVBi, spiro-6P, stilbene-phenylene (DSB), stilbene-arylide (DSA), polyfluorene (PFO) polymers and poly(p-phenylenevinylene) polymers as a second dopant. In addition, the second dopant may use metal complexes and / or organometallic complexes, such as (4,6-F2ppy)2Irpic, perylene and its derivatives, etc. Meanwhile, in the organic electroluminescent device 10 of the embodiment, which includes the fused polycyclic compound of the embodiment as the first dopant of the emission layer EML, the emission layer EML can emit green light or red light. In this case, the second dopant material used can be the above-mentioned suitable (e.g., known) dopant, suitable (e.g., known) green fluorescent dopant or suitable (e.g., known) red fluorescent dopant.

[0108] In the organic electroluminescent device 10 of the embodiment, the emission layer EML can be a phosphorescent emission layer. For example, a fused polycyclic compound according to the embodiment can be included in the emission layer EML as a phosphorescent host material.

[0109] In the organic electroluminescent device 10 of the embodiment, such as Figures 1 to 3 As shown, the electron transport region (ETR) is disposed on the emitter layer (EML). The electron transport region (ETR) may include a hole blocking layer (HBL), an electron transport layer (ETL), and / or an electron injection layer (EIL). However, embodiments of the inventive concept are not limited thereto.

[0110] The electronic transmission region (ETR) can have a single layer made of a single material, a single layer made of multiple different materials, or a multi-layer structure with multiple layers made of multiple different materials.

[0111] For example, the electron transport region (ETR) can have a monolayer structure of an electron injection layer (EIL) or an electron transport layer (ETL), or a monolayer structure formed using an electron injection material and an electron transport material. Furthermore, the ETR can have a monolayer structure comprising a variety of different materials, or 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 emitter layer (EML), but this disclosure is not limited thereto. The thickness of the ETR can be, for example, from about 1,000 Å to about 1,500 Å.

[0112] Electron transport regions (ETRs) can be formed using a variety of suitable methods such as vacuum deposition, spin coating, casting, Langmuir-Blodget (LB) methods, inkjet printing, laser printing, and / or laser-induced thermal imaging (LITI).

[0113] If the electron transport region (ETR) includes an electron transport layer (ETL), then the ETR may include anthracene compounds. The ETR may include, for example, tris(8-hydroxyquinoline)aluminum (Alq3), 1,3,5-tris[(3-pyridyl)-benzyl-3-yl]benzene, 2,4,6-tris(3'-(pyridyl-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-benzimidazol-2-yl)benzene (TPBi), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), 3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2, 4-Triazole (TAZ), 4-(naphth-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 (Bebq2), 9,10-bis(naphth-2-yl)anthracene (ADN), diphenyl(4-(triphenylsilyl)phenyl)phosphine oxide (TSPO1), bis[2-(diphenylphosphino)phenyl]ether oxide (DPEPO), or mixtures thereof, but this disclosure is not limited thereto. The thickness of the electron transport layer (ETL) can be from about 100 Å to about 1,000 Å, and can be, for example, from about 150 Å to about 500 Å. When the thickness of the electron transport layer (ETL) meets the above range, satisfactory electron transport performance can be obtained without significantly increasing the driving voltage.

[0114] If the electron transport region (ETR) includes an electron injection layer (EIL), the ETR may include, for example, LiF, lithium 8-hydroxyquinoline (LiQ), Li₂O, BaO, NaCl, CsF, lanthanides (such as Yb), and / or metal halides (such as RbCl and / or RbI). However, embodiments of the inventive concept are not limited thereto. The electron injection layer (EIL) may also be formed using a mixture of an electron injection material and an insulating organometallic salt. The organometallic salt may be a material having a band gap of about 4 eV or greater. In one embodiment, the organometallic salt may include, for example, a metal acetate, a metal benzoate, a metal acetoacetate, a metal acetylacetonate, and / or a metal stearate. The thickness of the electron injection layer (EIL) may be from about 1 Å to about 500 Å or from about 3 Å to about 300 Å. If the thickness of the electron injection layer (EIL) meets the above ranges, satisfactory electron injection performance can be obtained without significantly increasing the driving voltage.

[0115] The electron transport region (ETR) may include a hole blocking layer (HBL) as described above. The hole blocking layer (HBL) may include, for example, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and / or 4,7-diphenyl-1,10-phenanthroline (Bphen). However, embodiments of the inventive concept are not limited thereto.

[0116] The second electrode EL2 is disposed on the electron transport region ETR. The second electrode EL2 can be a common electrode or a cathode. The second electrode EL2 can be a transmission electrode, a transmission-reflection electrode, or a reflection electrode. For example, the second electrode EL2 may include at least one selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn, or may include at least one selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn. Two or more compounds thereof, mixtures of two or more selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn, or oxides of Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn. If the second electrode EL2 is a transmission electrode, then the second electrode EL2 may include a transparent metallic material, such as ITO, IZO, ZnO, ITZO, etc.

[0117] If the second electrode EL2 is a transmissive or reflective electrode, then 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 composites, or mixtures thereof (e.g., a mixture of Ag and Mg). The second electrode EL2 may have a multilayer structure, which includes a reflective or transmissive layer formed using the above-described materials and a transparent conductive layer formed using ITO, IZO, ZnO, ITZO, etc.

[0118] In one embodiment, the second electrode EL2 can be connected to an auxiliary electrode. If the second electrode EL2 is connected to the auxiliary electrode, the resistance of the second electrode E2 can be reduced.

[0119] Furthermore, the capping layer CPL can be further disposed on the second electrode EL2 of the organic electroluminescent device 10 in the embodiment. The capping layer CPL may include, for example, α-NPD, NPB, TPD, m-MTDATA, Alq3, CuPc, N4,N4,N4',N4'-tetra(biphenyl-4-yl)biphenyl-4,4'-diamine (TPD15), 4,4',4”-tris(carbazole-9-yl)triphenylamine (TCTA), etc.

[0120] The organic electroluminescent device 10 according to an embodiment of the inventive concept includes the fused polycyclic compound of the embodiment in the emitter layer EML disposed between the first electrode EL1 and the second electrode EL2, thereby exhibiting high emission efficiency performance. Furthermore, the fused polycyclic compound according to the embodiment can be a thermally activated delayed fluorescence dopant, and the emitter layer EML can include the fused polycyclic compound of the embodiment to emit thermally activated delayed fluorescence. Therefore, high emission efficiency performance can be achieved.

[0121] Additionally, the fused polycyclic compound of the embodiments may be included in an organic layer other than the emitting layer EML as a material for the organic electroluminescent device 10. For example, the organic electroluminescent device 10 according to the inventive concept may include a fused polycyclic compound in at least one of the organic layers disposed between the first electrode EL1 and the second electrode EL2 or in the capping layer CPL disposed on the second electrode EL2.

[0122] Compared to existing DABNA series compounds that only include N or B as cyclic heteroatoms, the fused polycyclic compounds of the embodiments must include Si as a cyclic heteroatomum to form the fused ring and have a relatively high lowest triplet excitation level (T1 level). Therefore, if used as materials for organic electroluminescent devices, the efficiency of organic electroluminescent devices can be further improved.

[0123] In the following description, fused polycyclic compounds and organic electroluminescent devices according to embodiments of the inventive concept will be illustrated with reference to examples and comparative examples. The following examples are merely illustrative to aid in understanding the inventive concept, and the scope of the inventive concept is not limited thereto.

[0124] Example 1. Synthesis of fused polycyclic compounds First, the method for synthesizing fused polycyclic compounds according to exemplary embodiments will be specifically described with reference to the synthesis methods of compounds 2, 5, 14, 15, and 18. Furthermore, the synthesis methods for fused polycyclic compounds described below are merely examples, and the synthesis methods for fused polycyclic compounds according to embodiments of the inventive concept are not limited thereto.

[0125] (1) Synthesis of compound 2 The fused polycyclic compound 2 according to the embodiment can be synthesized, for example, by following steps [1-1] to [1-6].

[0126] [1-1] Preparation of bis(2-bromophenyl)amine

[0127] In a thoroughly dried 500 mL three-necked round-bottom flask, 2-bromoaniline (15 g, 0.087 mol) and 1-bromo-2-iodobenzene (29.6 g, 0.105 mol) were dissolved in 200 mL toluene. Then, sodium tert-butoxide (16.76 g, 0.174 mol), Pd(dppf)Cl2 (12.43 g, 0.017 mol), and tri-tert-butylphosphine (1.82 g, 0.009 mol) were added, followed by reflux and stirring for approximately 12 hours. After the reaction was complete, the solvent was removed, and the mixture was extracted three times with dichloromethane. The extracted organic layers were dried over anhydrous MgSO4, and the solvent was removed using a rotary evaporator. The crude product was then separated by column chromatography using n-hexane as a solvent to obtain 18.3 g (yield = 64%) of the compound (colorless oil).

[0128] [1-2] Preparation of N,N-bis(2-bromophenyl)-N-(4-methoxybenzyl)amine

[0129] Under a nitrogen atmosphere, bis(2-bromophenyl)amine (39 g, 119.2 mmol), NaH (3.43 g, 143.1 mmol), and 250 mL of DMF were added (e.g., added) to a thoroughly dried 500 mL three-necked round-bottom flask and stirred at room temperature (approximately 25 °C) for about 1 hour. Then, 1-(chloromethyl)-4-methoxybenzene (20.54 g, 131.2 mmol) was added dropwise, and the mixture was stirred at room temperature for about 14 hours. After the reaction was complete, 500 mL of distilled water was added dropwise to the product, and the mixture was filtered and the precipitated solid was separated. The filtered solid was redissolved in dichloromethane and extracted three times. The extracted organic layers were dried over anhydrous MgSO4, and the solvent was removed using a rotary evaporator. The crude product was separated by column chromatography using a dichloromethane (MC) / hexane (hex) solvent of 3:1 to obtain 46.8 g (yield = 87%) of the compound.

[0130] Preparation of [1-3]5-(4-methoxybenzyl)-10,10-diphenyl-5,10-dihydrodibenzo[b,e][1,4]azasilane

[0131] 2-Bromo-N-(2-Bromophenyl)-N-(4-methoxybenzyl)aniline (9.00 g, 20.1 mmol) and 60 mL of diethyl ether were placed (e.g., added) into a thoroughly dried 150 mL three-necked round-bottom flask and stirred. The reaction temperature was cooled to approximately 0 °C, and 2.5 M n-BuLi / hex (17.7 mL, 44.2 mmol) was added dropwise. After stirring for approximately 30 minutes while maintaining the reaction temperature, dichlorodiphenylsilane (5.6 g, 22.1 mmol) dissolved in 20 mL of diethyl ether was added dropwise, and the mixture was stirred at room temperature for approximately 4 hours. After the reaction was complete, the solvent was removed, and the mixture was extracted three times with ethyl acetate. The extracted organic layers were dried over anhydrous MgSO4, and the solvent was removed using a rotary evaporator. The crude product thus obtained was separated by column chromatography using a dichloromethane / hexane (3 / 1) solvent to obtain 7.8 g (yield = 75%) of the compound.

[0132] Preparation of [1-4]10,10-diphenyl-5,10-dihydrodibenzo[b,e][1,4]azasilane

[0133] 37 g (78.8 mmol) of 5-(4-methoxybenzyl)-10,10-diphenyl-5,10-dihydrodibenzo[b,e][1,4]azasilane, DDQ (19.67 g, 86.6 mmol), 370 mL of toluene, and 37 mL of H₂O were added to a thoroughly dried 150 mL three-necked round-bottom flask and stirred at approximately 80 °C for about 14 hours. After the reaction was complete, the solvent was removed, and the mixture was extracted three times with ethyl acetate. The extracted organic layers were dried over anhydrous MgSO₄, and the solvent was removed using a rotary evaporator. The crude product obtained was separated by column chromatography using hexane / ethyl acetate (EA) (7 / 1) solvent to give 7.5 g (yield = 27%) of the compound.

[0134] Preparation of [1-5]5-(2-bromophenyl)-10,10-diphenyl-5,10-dihydrodibenzo[b,e][1,4]azasilane

[0135] In a thoroughly dried 250 mL three-necked round-bottom flask, 10,10-diphenyl-5,10-dihydrodibenzo[b,e][1,4]azasilane (5 g, 0.014 mol) and 1-bromo-2-iodobenzene (4.05 g, 0.014 mol) were dissolved in 130 mL of toluene. Then, sodium tert-butoxide (2.75 g, 0.029 mol), tri-tert-butylphosphine (0.29 g, 0.0014 mol), and Pd₂(dba)₃ (0.65 g, 0.0007 mol) were added, followed by reflux and stirring for approximately 12 hours. After the reaction was complete, the solvent was removed, and the mixture was extracted three times with dichloromethane. The extracted organic layers were dried over anhydrous MgSO₄, and the solvent was removed using a rotary evaporator. The crude product obtained was separated by column chromatography using MC / hexane solvent to obtain 4 g (yield = 55%) of the compound.

[0136] [1-6] Preparation of Compound 2

[0137] 5-(2-bromophenyl)-10,10-diphenyl-5,10-dihydrodibenzo[b,e][1,4]azasilane (1 eq) was dissolved in THF and cooled to approximately -78°C. Then, n-BuLi (2.2 eq) was slowly added. After stirring at low temperature for approximately 2 hours, a solution obtained by dissolving dimethyl thimerosylborate (2.0 eq) in THF was added to the reactor. After stirring again at approximately -78°C for approximately 1 hour, stirring was performed at room temperature for approximately 2 hours. The reaction mixture was then refluxed and stirred at approximately 80°C for approximately 24 hours, and then poured into an aqueous solution of NH4Cl to complete the reaction. The reaction product was extracted three times with distilled water and EA, dried over anhydrous MgSO4 under reduced pressure. The resulting organic layer was separated by column chromatography (MC / hex) to obtain compound 2 (yield: 15%).

[0138] (2) Synthesis of compound 15 The fused polycyclic compound 15 according to the embodiment can be synthesized, for example, by the following steps [2-1] to [2-3].

[0139] Preparation of [2-1] 3-Bromo-2-chloro-N,N-diphenylaniline

[0140] In a thoroughly dried 250 mL three-necked round-bottom flask, 1,3-dibromo-2-chlorobenzene (10 g, 0.037 mol) and diphenylamine (6.3 g, 0.037 mol) were dissolved in 130 mL of toluene. Then, sodium tert-butoxide (7.11 g, 0.074 mol), tri-tert-butylphosphine (0.75 g, 0.004 mol), and Pd₂(dba)₃ (1.7 g, 0.002 mol) were added, followed by reflux and stirring for approximately 12 hours. After the reaction was complete, the solvent was removed, and the mixture was extracted three times with dichloromethane. The extracted organic layers were dried over anhydrous MgSO₄, and the solvent was removed using a rotary evaporator. The crude product was then separated by column chromatography using MC / n-hexane solvent to obtain 5 g (yield = 38%) of 3-bromo-2-chloro-N,N-diphenylaniline.

[0141] Preparation of [2-2]2-chloro-3-(10,10-diphenyl-5,10-dihydrodibenzo[b,e][1,4]azasilyl-5(10H)-yl)-N,N-diphenylaniline

[0142] In a thoroughly dried 250 mL three-necked round-bottom flask, 3-bromo-2-chloro-N,N-diphenylaniline (5 g, 0.014 mol) and 10,10-diphenyl-5,10-dihydrodibenzo[b,e][1,4]azasilane (4.87 g, 0.014 mol) were dissolved in 70 mL of toluene. Then, sodium tert-butoxide (2.7 g, 0.028 mol), tri-tert-butylphosphine (0.3 g, 0.001 mol), and Pd₂(dba)₃ (0.64 g, 0.0007 mol) were added, followed by reflux and stirring for approximately 12 hours. After the reaction was complete, the solvent was removed, and the mixture was extracted three times with dichloromethane. The extracted organic layers were dried over anhydrous MgSO₄, and the solvent was removed using a rotary evaporator. The crude product was separated by column chromatography using MC / hexane solvent to obtain 5 g (yield = 57%) of 2-chloro-3-(10,10-diphenyl-5,10-dihydrodibenzo[b,e][1,4]azasilyl-5(10H)-yl)-N,N-diphenylaniline.

[0143] [2-3] Preparation of Compound 15

[0144] Under a nitrogen atmosphere, at approximately -30°C, a 1.7 M solution of tert-butyllithium pentane (27.6 mL) was added to a flask comprising 2-chloro-3-(10,10-diphenyl-5,10-dihydrodibenzo[b,e][1,4]azasilyl-5(10H)-yl)-N,N-diphenylaniline and tert-butylbenzene (150 mL). After the addition was complete, the temperature was raised to approximately 60°C and stirred for approximately 2 hours. Then, components with boiling points lower than that of tert-butylbenzene were removed by vacuum distillation. The temperature was cooled to approximately -30°C, boron tribromide (5.1 mL) was added, and the temperature was then raised to room temperature and stirred for approximately 0.5 hours. Afterward, the temperature was cooled to approximately 0°C, and N,N-diisopropylethylamine (15.6 mL) was added. Stirring was continued until the heat was dissipated, and the temperature was raised to approximately 120°C and heated and stirred for approximately 3 hours. The reaction solution was cooled to room temperature, extracted with a cooled aqueous sodium acetate solution, and separated by column chromatography. The solid obtained by removing the solvent by vacuum distillation was dissolved in toluene and recrystallized by adding hexane to obtain compound 15 (6.0 g).

[0145] 2. Fabrication and evaluation of organic electroluminescent devices, including fused polycyclic compounds. (Manufacturing of organic electroluminescent devices) The organic electroluminescent devices of the embodiments, comprising the fused polycyclic compounds of the embodiments in the emitter layer, were fabricated using the following method. The organic electroluminescent devices of Examples 1 to 5 were fabricated using the fused polycyclic compounds of compounds 2, 5, 14, 15, and 18 as respective dopant materials for the emitter layer. The organic electroluminescent device of Comparative Example 1 was fabricated using comparative compound C1 as the dopant material in the emitter layer.

[0146] On a glass substrate, ITO with a thickness of approximately 1,200 Å was patterned and washed with isopropanol and ultrapure water, followed by ultrasonic washing, exposure to UV for approximately 30 minutes, and ozone treatment. Then, NPD was deposited to a thickness of approximately 300 Å to form a hole injection layer, TCTA was deposited to a thickness of approximately 200 Å, and CzSi was deposited to a thickness of approximately 100 Å to form a hole transport layer.

[0147] On the hole transport layer, DPEPO and various fused polycyclic compounds or comparative compound C1 of the embodiments of the inventive concept are co-deposited in a 90:10 ratio to form an emission layer with a thickness of approximately 200 Å. That is, the emission layer formed by co-deposition is formed by mixing compounds 2, 5, 14, 15 and 18 of Examples 1 to 5 with DPEPO and depositing the mixture, or by mixing comparative compound C1 of Comparative Example 1 with DPEPO and depositing the mixture.

[0148] On the emitter layer, an electron transport layer of approximately 200 Å thickness is formed using DPEPO. Then, an electron injection layer is formed in the order stated above by depositing TPBi to a thickness of approximately 300 Å and LiF to a thickness of approximately 10 Å. A second electrode of approximately 3,000 Å thickness is then formed on the electron injection layer using aluminum (Al).

[0149] Table 1 below lists the compounds used in Examples 1 through 5 and Comparative Example 1.

[0150] Table 1

[0151] In addition, other compounds used in the fabrication of the organic electroluminescent devices of Example and Comparative Example 1 are shown below.

[0152]

[0153] (Performance evaluation of organic electroluminescent devices) Table 2 shows the evaluation results of the organic electroluminescent devices of Examples 1 to 5 and Comparative Example 1. Table 2 shows and compares the driving voltage, emission efficiency, and external quantum efficiency (EQE) of the organic electroluminescent devices thus fabricated.

[0154] As shown in Table 2, the voltage and current densities were measured using a source meter (Keithley Instrument Co., SMU 236) in the performance evaluation results for the example and comparative examples. Emission efficiency is expressed relative to 10 mA / cm². 2 The current efficiency of the current density.

[0155] Table 2

[0156] Referring to the results in Table 2, it was found that, compared with the comparative examples, the organic electroluminescent devices according to the examples using fused polycyclic compounds as materials for the emission layer according to embodiments of the inventive concept exhibit similar driving voltage values ​​as well as relatively high emission efficiency and external quantum efficiency.

[0157] When compared with the comparative compound C1, the example compound exhibits TADF performance using the multiple resonance phenomenon of the aromatic ring (which forms a fused ring), and also possesses high rigidity and large volume by including Si as a cyclic heteroatom (which forms a fused ring). Therefore, the example organic light-emitting device can exhibit improved emission efficiency compared to the organic light-emitting device of the comparative example.

[0158] The fused polycyclic compounds of the embodiments include fused ring structures containing Si as cyclic heteroatoms and possessing high T1 energy levels and small ΔE. ST The fused polycyclic compounds of the embodiments have high efficiency and can therefore be used as delayed fluorescence emission materials. Additionally, the fused polycyclic compounds of the embodiments can be used as dopant materials for the emission layer in organic electroluminescent devices to improve device efficiency. Furthermore, the fused polycyclic compounds of the embodiments include fused ring structures containing Si as cyclic heteroatoms and can exhibit high rigidity and long lifetime characteristics.

[0159] The organic electroluminescent device of the embodiments includes the fused polycyclic compound of the embodiments and can exhibit improved emission efficiency. Furthermore, the organic electroluminescent device of the embodiments includes the fused polycyclic compound of the embodiments as a material for the emission layer and can achieve high emission efficiency in the blue light wavelength region.

[0160] The organic electroluminescent device according to the embodiments can exhibit improved device characteristics with reduced driving voltage and high efficiency.

[0161] The fused polycyclic compounds of the embodiments can be included in the emitting layer of the organic electroluminescent device and can help improve the efficiency of the organic electroluminescent device.

[0162] When expressions such as “at least one of…” or “at least one selected from…” follow a list of elements, they modify the entire list of elements rather than individual elements within that list. Furthermore, when describing embodiments of the invention, the use of “may” refers to “one or more embodiments of the invention.” Additionally, the term “exemplary” is intended to indicate an example or illustration. As used herein, the terms “basically,” “about,” and similar terms are used as approximate terms rather than terms of degree and are intended to account for inherent deviations in measured or calculated values ​​that will be recognized by one of ordinary skill in the art. Furthermore, any numerical range stated herein is intended to include all subranges of the same numerical precision contained within the stated range. For example, the range “1.0 to 10.0” is intended to include all subranges between (and including) the stated minimum value of 1.0 and the stated maximum value of 10.0, i.e., having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as 2.4 to 7.6. Any maximum numerical limit stated herein is intended to include all lower numerical limits contained herein, and any minimum numerical limit stated herein is intended to include all higher numerical limits contained herein. Therefore, the applicant reserves the right to amend this specification (including the claims) to expressly state any sub-scopes included within the scope expressly stated herein. All such scopes are inherently described in this specification such that any modification to expressly stated any such sub-scopes would be compliant.

[0163] Although exemplary embodiments of the invention have been described, it is understood that the invention should not be limited to these exemplary embodiments, but rather various changes and modifications can be made by those skilled in the art within the spirit and scope of the invention as claimed above and its equivalents.

Claims

1. A fused polycyclic compound, said fused polycyclic compound being represented by the following formula 1-1: Equation 1-1 ， in, In Equation 1-1, X1 is B. R c and R d Each is independently a hydrogen atom, a deuterium atom, or an aryl group consisting of 6 to 60 substituted or unsubstituted carbon atoms forming a ring. R n It is a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, a substituted or unsubstituted aryl group with 6 to 60 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group with 2 to 60 ring-forming carbon atoms, and R n Optionally, it can combine with adjacent groups to form a ring. n is an integer between 0 and 5, and R 11 To R 21 Each of them is independently a hydrogen atom, a deuterium atom, a halogen atom, a boron group, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, a substituted or unsubstituted aryl group with 6 to 60 cyclic carbon atoms, or a substituted or unsubstituted heteroaryl group with 2 to 60 cyclic carbon atoms.

2. The fused polycyclic compound according to claim 1, wherein, The absolute value of the difference between the lowest singlet excitation level and the lowest triplet excitation level of the fused polycyclic compound is 0.1 eV or less.

3. The fused polycyclic compound according to claim 1, wherein, R c and R d All are independently unsubstituted phenyl groups.

4. The fused polycyclic compound according to claim 1, wherein, The fused polycyclic compound is any one selected from the compounds in group 1 below: Compound group 1 。 5. An organic electroluminescent device, the organic electroluminescent device comprising: First electrode; The second electrode is opposite to the first electrode; as well as The emission layer is located between the first electrode and the second electrode. The emitter layer comprises: a first body, a second body different from the first body, and a first dopant. Wherein, the first dopant is a fused polycyclic compound according to any one of claims 1 to 4.

6. The organic electroluminescent device according to claim 5, wherein, The emission layer emits delayed fluorescence.

7. The organic electroluminescent device according to claim 5, wherein, The emitter layer further includes a second dopant, and The lowest triplet excitation energy level of the second dopant is lower than that of the first dopant.

8. The organic electroluminescent device according to claim 5, wherein, The emitter layer further includes a second dopant, and wherein, The first dopant is a delayed fluorescence dopant, and The second dopant is a fluorescent dopant.

9. The organic electroluminescent device according to claim 5, wherein, The emitter layer further includes a second dopant, and wherein, The second dopant includes metal complexes, organometallic complexes, or perylene derivatives.

10. A display device comprising an organic electroluminescent device according to any one of claims 5 to 9.

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