Novel compound and organic light-emitting device containing the same

Abstract

The present invention provides novel compounds and organic light-emitting devices using the same.

Description

Technical Field

[0001] Cross-references to related applications

[0002] This application claims priority based on Korean Patent Application No. 10-2020-0150097 filed on November 11, 2020, and incorporates all contents disclosed in the document of the Korean patent application as a part of this specification.

[0003] The present invention relates to novel compounds and organic light-emitting devices containing the same. Background Art

[0004] Organic light emitting diodes (OLEDs) are currently under extensive research due to their wide viewing angles, excellent contrast, and fast response times, as well as their superior brightness, drive voltage, and response speed.

[0005] An organic light-emitting device typically has a structure comprising an anode, a cathode, and an organic layer positioned between the anode and cathode. To improve the efficiency and stability of an organic light-emitting device, the organic layer is often formed from multiple layers composed of different materials. For example, it can be composed of a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer. In such an organic light-emitting device structure, when a voltage is applied between the two electrodes, holes are injected from the anode into the organic layer, and electrons are injected from the cathode into the organic layer. When the injected holes and electrons meet, excitons are formed. When these excitons transition back to the ground state, light is emitted.

[0006] As for organic substances used in the organic light-emitting devices described above, there is a continuous demand for the development of new materials.

[0007] Prior art literature

[0008] Patent Literature

[0009] (Patent Document 0001) Korean Patent Publication No. 10-2000-0051826 Summary of the Invention

[0010] Technical issues

[0011] The present invention relates to novel compounds and organic light-emitting devices containing the same.

[0012] Solution to the problem

[0013] The present invention provides a compound represented by the following Chemical Formula 1:

[0014] [Chemical Formula 1]

[0015]

[0016] In the above chemical formula 1,

[0017] R is independently substituted or unsubstituted C 1-60 alkyl,

[0018] R1 to R4 are each independently hydrogen, deuterium, substituted or unsubstituted C 1-60 Alkyl, substituted or unsubstituted C 6-60 aryl group, or a substituent represented by the following chemical formula 2, but at least one of R1 to R4 is a substituent represented by the following chemical formula 2,

[0019] [Chemical Formula 2]

[0020]

[0021] In the above chemical formula 2,

[0022] X1 to X3 are each independently N or CH, but at least one of X1 to X3 is N,

[0023] L1 to L3 are each independently a single bond, or a substituted or unsubstituted C 6-60 arylene groups,

[0024] n is 1, 2 or 3,

[0025] Ar1 and Ar2 are each independently substituted or unsubstituted C 6-60 Aryl; or substituted or unsubstituted C containing one or more heteroatoms of N, O and S 2-60 Heteroaryl.

[0026] In addition, the present invention provides an organic light-emitting device, which includes: a first electrode, a second electrode arranged opposite to the first electrode, and one or more organic layers arranged between the first electrode and the second electrode, wherein one or more of the organic layers contains the compound represented by the above Chemical Formula 1.

[0027] Effects of the Invention

[0028] The compound represented by the above Chemical Formula 1 can be used as a material for an organic layer of an organic light-emitting device, and can achieve improved efficiency, lower driving voltage, and / or improved lifespan characteristics in the organic light-emitting device. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 An example of an organic light-emitting device composed of a substrate 1 , an anode 2 , a hole transport layer 3 , a light-emitting layer 4 , an electron injection and transport layer 5 , and a cathode 6 is shown.

[0030] Figure 2 The diagram shows an example of an organic light-emitting device composed of a substrate 1, an anode 2, a hole injection layer 7, a hole transport layer 3, an electron suppression layer 8, a light-emitting layer 4, a hole blocking layer 9, an electron injection and transport layer 5, and a cathode 6. DETAILED DESCRIPTION

[0031] Hereinafter, the present invention will be described in more detail to facilitate understanding.

[0032] (Definition of terms)

[0033] In this manual, and It represents a bond to other substituents.

[0034] In the present specification, the term "substituted or unsubstituted" refers to a group selected from deuterium; a halogen group; a cyano group; a nitro group; a hydroxyl group; a carbonyl group; an ester group; an imide group; an amino group; a phosphine oxide group; an alkoxy group; an aryloxy group; an alkylthio group; Arylthio Alkylsulfonyl Arylsulfonyl Silyl; boryl; alkyl; cycloalkyl; alkenyl; aryl; aralkyl; aralkenyl; alkylaryl; alkylamino; aralkylamino; heteroarylamino; arylamino; arylphosphino; or substituted or unsubstituted with one or more substituents in a heteroaryl group containing one or more N, O and S atoms, or substituted or unsubstituted with a substituent formed by linking two or more substituents among the substituents exemplified above. For example, a "substituent formed by linking two or more substituents" can be a biphenyl group. That is, a biphenyl group can be an aryl group, and can also be interpreted as a substituent formed by linking two phenyl groups. As an example, the term "substituted or unsubstituted" can be understood as "unsubstituted; or substituted or unsubstituted with a substituent selected from deuterium, a halogen group, C 1-10 Alkyl, C 1-10 Alkoxy and C 6-20 In the present specification, the term “substituted by one or more substituents” can be understood to mean, for example, “substituted by one to five substituents” or “substituted by one or two substituents”.

[0035] In the present specification, the number of carbon atoms in the carbonyl group is not particularly limited, but preferably the number of carbon atoms is 1 to 40. Specifically, the substituents may be of the following structures, but are not limited thereto.

[0036]

[0037] In the present specification, the oxygen of the ester group may be substituted with a linear, branched, or cyclic alkyl group having 1 to 25 carbon atoms, or an aryl group having 6 to 25 carbon atoms. Specifically, the substituents may be those of the following structural formulas, but are not limited thereto.

[0038]

[0039] In the present specification, the number of carbon atoms in the imide group is not particularly limited, but preferably the number of carbon atoms is 1 to 25. Specifically, the substituent may be a substituent of the following structure, but the substituent is not limited thereto.

[0040]

[0041] In the present specification, specific examples of the silyl group include trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, vinyldimethylsilyl, propyldimethylsilyl, triphenylsilyl, diphenylsilyl, and phenylsilyl, but are not limited thereto.

[0042] In the present specification, specific examples of the boryl group include trimethylboryl, triethylboryl, tert-butyldimethylboryl, triphenylboryl, and phenylboryl, but are not limited thereto.

[0043] In the present specification, examples of the halogen group include fluorine, chlorine, bromine, and iodine.

[0044] In the present specification, the alkyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 1 to 40. According to one embodiment, the number of carbon atoms in the alkyl group is 1 to 20. According to another embodiment, the number of carbon atoms in the alkyl group is 1 to 10. According to another embodiment, specific examples of the alkyl group include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethylbutyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, 1-ethyl-propyl, 1,1-dimethylpropyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n-heptyl, isohexyl, 1-methylhexyl, 2-methylhexyl, 3-methylhexyl, 4-methylhexyl, 5-methylhexyl, cyclopentylmethyl, cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2,4,4-trimethyl-1-pentyl, 2,4,4-trimethyl-2-pentyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, etc., but are not limited thereto.

[0045] In the present specification, the alkenyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 2 to 40. According to one embodiment, the alkenyl group has 2 to 20 carbon atoms. According to another embodiment, the alkenyl group has 2 to 10 carbon atoms. According to another embodiment, the alkenyl group has 2 to 6 carbon atoms. Specific examples include vinyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 3-methyl-1-butenyl, 1,3-butadienyl, allyl, 1-phenylethen-1-yl, 2-phenylethen-1-yl, 2,2-diphenylethen-1-yl, 2-phenyl-2-(naphthalen-1-yl)ethen-1-yl, 2,2-bis(diphenyl-1-yl)ethen-1-yl, stilbene, and styryl, but are not limited thereto.

[0046] In this specification, the cycloalkyl group is not particularly limited, but is preferably a cycloalkyl group having 3 to 60 carbon atoms. According to one embodiment, the cycloalkyl group has 3 to 30 carbon atoms. According to another embodiment, the cycloalkyl group has 3 to 20 carbon atoms. According to another embodiment, the cycloalkyl group has 3 to 6 carbon atoms. Specific examples include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3,4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, and cyclooctyl.

[0047] In this specification, the aryl group is not particularly limited, but is preferably an aryl group having 6 to 60 carbon atoms, and may be a monocyclic aryl group or a polycyclic aryl group having aromaticity. According to one embodiment, the carbon number of the aryl group is 6 to 30. According to one embodiment, the carbon number of the aryl group is 6 to 20. Regarding the aryl group, as a monocyclic aryl group, it may be phenyl, biphenyl, terphenyl, etc., but is not limited thereto. As the polycyclic aryl group, it may be naphthyl, anthracenyl, phenanthrenyl, triphenylene, pyrenyl, perylene, Base, etc., but not limited to this.

[0048] In this specification, the fluorenyl group may be substituted, and two substituents may be combined with each other to form a spiro structure. etc. However, the present invention is not limited thereto.

[0049] In the present specification, the heteroaryl group is a heteroaryl group containing one or more of O, N, Si and S as hetero elements, and the number of carbon atoms is not particularly limited, but preferably the number of carbon atoms is 2 to 60. Examples of the heteroaryl group include thienyl, furyl, pyrrolyl, imidazolyl, thiazolyl, Azolyl, oxadiazolyl, triazolyl, pyridyl, bipyridyl, pyrimidinyl, triazinyl, acridinyl, pyridazinyl, pyrazinyl, quinolinyl, quinazolinyl, quinoxalinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolinyl, indolyl, carbazolyl, benzo[omicron] oxazolyl, benzimidazolyl, benzothiazolyl, benzocarbazolyl, benzothiophenyl, dibenzothiophenyl, benzofuranyl, phenanthroline, isothiophene oxazolyl, thiadiazolyl, phenothiazinyl and dibenzofuranyl, etc., but are not limited thereto.

[0050] In this specification, the aryl group in aralkyl, aralkenyl, alkylaryl, arylamine, and arylsilyl groups is the same as the examples of aryl groups described above. In this specification, the alkyl group in aralkyl, alkylaryl, and alkylamine groups is the same as the examples of alkyl groups described above. In this specification, the heteroaryl group in heteroarylamine is the same as the examples of heteroaryl groups described above. In this specification, the alkenyl group in aralkenyl is the same as the examples of alkenyl groups described above. In this specification, the description of aryl groups described above is applicable except that an arylene group is a divalent group. In this specification, the description of heteroarylene groups described above is applicable except that a heteroarylene group is a divalent group. In this specification, the description of heteroaryl groups described above is applicable except that a hydrocarbon ring is not a monovalent group but is formed by bonding two substituents. In this specification, the description of aryl or cycloalkyl groups described above is applicable except that a heterocycle is not a monovalent group but is formed by bonding two substituents. In this specification, the description of heteroaryl groups described above is applicable except that a heterocycle is not a monovalent group but is formed by bonding two substituents.

[0051] (Compound)

[0052] In another aspect, the present invention provides a compound represented by the above Chemical Formula 1.

[0053] Specifically, the compound represented by the above Chemical Formula 1 relates to a compound in which an N-containing six-membered heterocyclic substituent is bonded to a (1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene) core, and is characterized in that the N-containing six-membered heterocyclic substituent is substituted on at least one of the carbon atoms of the benzene ring of the above core.

[0054] Compounds with this structure, by having one or more nitrogen-containing six-membered heterocyclic substituents only on the benzene ring of the core, create intramolecular polarization, resulting in an enhanced dipole moment and high thermal stability, making them highly stable even at high vapor deposition temperatures. Consequently, organic light-emitting devices (OLEDs) employing these compounds can exhibit higher efficiency, lower driving voltage, and longer lifespans compared to existing OLEDs.

[0055] In the above chemical formula 1, R can be independently C 1-10 alkyl.

[0056] For example, each R independently can be methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, or tert-butyl.

[0057] In this case, all R's may be the same.

[0058] In addition, all R groups may be methyl groups.

[0059] In addition, in the above Chemical Formula 1, R1 to R4 are each independently hydrogen, deuterium, substituted or unsubstituted C 1-60 Alkyl, or substituted or unsubstituted C 6-60 aryl group, but at least one of R1 to R4 is a substituent represented by the above chemical formula 2. In this case, when there are two or more substituents represented by the above chemical formula 2 in the above chemical formula 1, the two or more substituents represented by the above chemical formula 2 are the same as or different from each other.

[0060] Specifically, one of R1 to R4 is a substituent represented by the above Chemical Formula 2, or

[0061] Two of R1 to R4 may be substituents represented by the above-mentioned Chemical Formula 2.

[0062] In this case, the compound may be represented by any one of the following chemical formulas 1A to 1F:

[0063] [Chemical Formula 1A]

[0064]

[0065] [Chemical Formula 1B]

[0066]

[0067] [Chemical Formula 1C]

[0068]

[0069] [Chemical Formula 1D]

[0070]

[0071] [Chemical Formula 1E]

[0072]

[0073] [Chemical Formula 1F]

[0074]

[0075] In the above Chemical Formulas 1A to 1F,

[0076] R, R1 to R4, X1 to X3, L1 to L3, n, Ar1 and Ar2 are the same as defined in the above Chemical Formula 1.

[0077] At this time, R1 to R4 that are not substituents represented by the above Chemical Formula 2 may each independently be hydrogen or deuterium.

[0078] In addition, in the above chemical formula 2, it can be:

[0079] X1 is N, X2 and X3 are CH; or

[0080] X2 is N, X1 and X3 are CH; or

[0081] X1 and X2 are N, and X3 is CH; or

[0082] X2 and X3 are N, and X1 is CH; or

[0083] X1 to X3 are all N.

[0084] In addition, in the above chemical formula 2, L1 and L2 can each independently be a single bond, or an unsubstituted or deuterated C 6-20 Arylene.

[0085] Specifically, L1 and L2 may each independently be a single bond, a phenylene group, or a naphthylene group.

[0086] For example, L1 and L2 may each independently be a single bond or any one selected from the following groups, but are not limited thereto.

[0087]

[0088] In addition, in the above Chemical Formula 2, L3 can be each independently a single bond, or an unsubstituted or deuterated C 6-20 Arylene.

[0089] Specifically, L3 may be a single bond, a phenylene group, a naphthylene group, or a biphenyldiyl group.

[0090] In this case, n can be 1 or 2.

[0091] For example, (L3) n It may be a single bond or any one selected from the following groups, but is not limited thereto.

[0092]

[0093] In the above Chemical Formula 2, Ar1 and Ar2 are each independently C 6-20 aryl, dibenzofuranyl or dibenzothiophenyl,

[0094] Here, Ar1 and Ar2 may be unsubstituted; or may be selected from deuterium, C 1-10 Alkyl and C 6-20 The aryl group is substituted by one or more substituents.

[0095] Specifically, Ar1 and Ar2 are each independently phenyl, biphenyl, terphenyl, naphthyl, phenanthrenyl, fluorenyl, dibenzofuranyl or dibenzothiophenyl,

[0096] Here, Ar1 and Ar2 may be unsubstituted; or may be selected from deuterium, C 1-10 Alkyl and C 6-20 The aryl group may be substituted with one or more substituents, for example, the aryl group may be substituted with one or more substituents selected from the group consisting of deuterium, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, and phenyl.

[0097] More specifically, Ar1 and Ar2 may each independently be a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a phenanthryl group, a 9,9-dimethylfluorenyl group, a 9,9-diphenylfluorenyl group, or a dibenzofuranyl group or a dibenzothiophenyl group.

[0098] For example, Ar1 and Ar2 can each independently be any one selected from the following groups, but are not limited thereto:

[0099]

[0100] In this case, Ar1 and Ar2 may be the same as each other. Alternatively, Ar1 and Ar2 may be different.

[0101] In addition, at least one of Ar1 and Ar2 may be a phenyl group, a naphthyl group, or a phenanthryl group.

[0102] In addition, the above compound can be represented by any one of the following chemical formulas 1-1 to 1-6:

[0103] [Chemical Formula 1-1]

[0104]

[0105] [Chemical formula 1-2]

[0106]

[0107] [Chemical formula 1-3]

[0108]

[0109] [Chemical formula 1-4]

[0110]

[0111] [Chemical Formula 1-5]

[0112]

[0113] [Chemical formula 1-6]

[0114]

[0115] In the above Chemical Formulas 1-1 to 1-6,

[0116] X1 to X3, L1 to L3, n, Ar1 and Ar2 are the same as defined in the above Chemical Formula 1.

[0117] In addition, for example, in the above chemical formulas 1-3 to 1-6, two substituents Can be the same as each other.

[0118] On the other hand, representative examples of the compound represented by the above Chemical Formula 1 are as follows:

[0119]

[0120]

[0121]

[0122]

[0123]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129]

[0130]

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139]

[0140]

[0141]

[0142]

[0143]

[0144]

[0145]

[0146]

[0147]

[0148]

[0149]

[0150]

[0151]

[0152]

[0153]

[0154]

[0155]

[0156]

[0157]

[0158]

[0159]

[0160]

[0161]

[0162]

[0163]

[0164]

[0165] On the other hand, as an example, when R1 of the compound represented by the above Chemical Formula 1 is a substituent represented by the above Chemical Formula 2, it can be produced by the production method shown in the following Reaction Formula 1:

[0166] [Reaction formula 1]

[0167]

[0168] In the above reaction formula 1, X is a halogen, preferably bromine or chlorine, and the definitions of other substituents are the same as described above.

[0169] Specifically, the compound represented by the above chemical formula 1 is manufactured by combining starting materials SM1 and SM2 via a Suzuki coupling reaction. Such a Suzuki coupling reaction is preferably carried out in the presence of a palladium catalyst and a base, and the reactive group used for the above reaction can be appropriately changed. The manufacturing method of such a compound represented by chemical formula 1 can be further specified in the manufacturing examples described later.

[0170] (Organic Light-Emitting Devices)

[0171] In another aspect, the present invention provides an organic light-emitting device comprising the compound represented by Chemical Formula 1. As an example, the present invention provides an organic light-emitting device comprising: a first electrode; a second electrode disposed opposite the first electrode; and one or more organic layers disposed between the first electrode and the second electrode, wherein one or more of the organic layers comprises the compound represented by Chemical Formula 1.

[0172] The organic layer of the organic light-emitting device of the present invention may be a single-layer structure or a multilayer structure comprising two or more organic layers. For example, the organic light-emitting device of the present invention may include a hole injection layer, a hole transport layer, an electron suppression layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and the like as organic layers. However, the structure of the organic light-emitting device is not limited to this and may include a smaller number of organic layers.

[0173] In addition, the organic layer may include a hole injection layer, a hole transport layer, or a layer that simultaneously injects and transports holes. The hole injection layer, hole transport layer, or layer that simultaneously injects and transports holes may include the compound represented by Chemical Formula 1.

[0174] In addition, the organic layer may include a light-emitting layer, and the light-emitting layer may include the compound represented by Chemical Formula 1.

[0175] In addition, the organic layer may include an electron injection layer, an electron transport layer, or a layer that simultaneously injects and transports electrons. The electron injection layer, electron transport layer, or layer that simultaneously injects and transports electrons may include the compound represented by Chemical Formula 1.

[0176] In addition, the organic layer may include a hole blocking layer or an electron injection and transport layer, and the hole blocking layer or the electron injection and transport layer may include the compound represented by Chemical Formula 1.

[0177] The organic layer of the organic light-emitting device of the present invention may have a single-layer structure or a multilayer structure comprising two or more organic layers stacked together. For example, in addition to the light-emitting layer, the organic light-emitting device of the present invention may include a hole injection layer and a hole transport layer between the first electrode and the light-emitting layer, and an electron transport layer and an electron injection layer between the light-emitting layer and the second electrode. However, the structure of the organic light-emitting device is not limited to this and may include a fewer or greater number of organic layers.

[0178] In addition, the organic light-emitting device according to the present invention may be an organic light-emitting device having a structure (normal type) in which the first electrode is an anode and the second electrode is a cathode, and an anode, one or more organic layers, and a cathode are sequentially stacked on a substrate. In addition, the organic light-emitting device according to the present invention may be an organic light-emitting device having an inverted structure (inverted type) in which the first electrode is a cathode and the second electrode is an anode, and a cathode, one or more organic layers, and an anode are sequentially stacked on a substrate. For example, the structure of an organic light-emitting device according to one embodiment of the present invention is shown in FIG. Figure 1 and 2 .

[0179] Figure 1 The diagram shows an example of an organic light-emitting device composed of a substrate 1, an anode 2, a hole transport layer 3, a light-emitting layer 4, an electron injection and transport layer 5, and a cathode 6. In the above structure, the compound represented by Chemical Formula 1 may be contained in the electron injection and transport layer.

[0180] Figure 2The diagram shows an example of an organic light-emitting device composed of a substrate 1, an anode 2, a hole injection layer 7, a hole transport layer 3, an electron suppression layer 8, a light-emitting layer 4, a hole blocking layer 9, an electron injection and transport layer 5, and a cathode 6.

[0181] In the structure as described above, the compound represented by the above Chemical Formula 1 may be included in the above electron injection and transport layer.

[0182] The organic light-emitting device according to the present invention can be manufactured using materials and methods known in the art, except that at least one of the organic layers contains the compound represented by Chemical Formula 1. Furthermore, when the organic light-emitting device includes multiple organic layers, the organic layers can be formed of the same substance or different substances.

[0183] For example, an organic light-emitting device according to the present invention can be manufactured by sequentially stacking a first electrode, an organic layer, and a second electrode on a substrate. In this case, the device can be manufactured as follows: a metal or a conductive metal oxide or an alloy thereof is deposited on a substrate using a PVD (physical vapor deposition) method such as sputtering or electron beam evaporation to form an anode. An organic layer comprising a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer is then formed on the anode. A cathode material is then deposited on the organic layer. Alternatively, an organic light-emitting device can be manufactured by sequentially depositing a cathode material, an organic layer, and an anode material on a substrate.

[0184] Furthermore, when manufacturing an organic light-emitting device, the compound represented by Chemical Formula 1 can be applied not only by vacuum evaporation but also by solution coating to form an organic layer. Solution coating methods include, but are not limited to, spin coating, dip coating, doctor blade coating, inkjet printing, screen printing, spraying, and roller coating.

[0185] In addition to these methods, an organic light-emitting device can also be manufactured by sequentially depositing a cathode material, an organic layer, and an anode material on a substrate (WO 2003 / 012890). However, the manufacturing method is not limited to this.

[0186] As an example, the first electrode is an anode and the second electrode is a cathode, or the first electrode is a cathode and the second electrode is an anode.

[0187] The anode material is preferably a material with a large work function to facilitate hole injection into the organic layer. Specific examples of the anode material include, but are not limited to, metals such as vanadium, chromium, copper, zinc, and gold, or their alloys; metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); combinations of metals and oxides such as ZnO:Al or SnO2:Sb; and conductive polymers such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDOT), polypyrrole, and polyaniline.

[0188] The cathode material is preferably one with a low work function to facilitate electron injection into the organic layer. Specific examples of cathode materials include, but are not limited to, metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or alloys thereof; and multilayer structures such as LiF / Al or LiO2 / Al.

[0189] The hole injection layer is a layer that injects holes from the electrode. As a hole injection material, it is preferably a compound that has the ability to transport holes, has the effect of injecting holes from the anode, has an excellent hole injection effect for the light-emitting layer or the light-emitting material, prevents the excitons generated in the light-emitting layer from migrating to the electron injection layer or the electron injection material, and has excellent thin film forming ability. The HOMO (highest occupied molecular orbital) of the hole injection material is preferably between the work function of the anode material and the HOMO of the surrounding organic layer. Specific examples of hole injection materials include metal porphyrins, oligothiophenes, arylamine organics, hexanitrile hexaazatriphenylene organics, quinacridone organics, perylene organics, anthraquinones, polyaniline, and polythiophene conductive polymers, but are not limited thereto.

[0190] The hole transport layer is a layer that receives holes from the hole injection layer and transports the holes to the light-emitting layer. The hole transport substance is a substance that can receive holes from the anode or the hole injection layer and transfer them to the light-emitting layer. A substance with a large hole mobility is suitable. As the hole transport substance, hexanitrile hexaazatriphenylene organic matter, arylamine organic matter, conductive polymer, and block copolymers having both conjugated and non-conjugated parts can be used, but are not limited to this. In addition, the hole transport layer can use the hole transport substance and be arranged as two or more layers in the organic light-emitting device. In this case, the hole transport substances contained in the two or more hole transport layers can be the same or different from each other.

[0191] The organic light-emitting device may also be provided with an electron suppression layer. Specifically, the electron suppression layer is formed on the hole transport layer, preferably in contact with the light-emitting layer, and improves the efficiency of the organic light-emitting device by regulating hole mobility, preventing excessive electron migration, and increasing the probability of hole-electron binding. The electron suppression layer comprises an electron-blocking substance. Examples of such electron-blocking substances include, but are not limited to, arylamine-based organic substances.

[0192] The above-mentioned luminescent material is a material that can receive holes and electrons from the hole transport layer and the electron transport layer, respectively, and combine them to emit light in the visible light region. It is preferably a material with high quantum efficiency for fluorescence or phosphorescence. Specific examples include 8-hydroxyquinoline aluminum complex (Alq3), carbazole compounds, dimerized styryl compounds; BAlq; 10-hydroxybenzoquinoline-metal compounds; benzo azole, benzothiazole and benzimidazole compounds; poly(p-phenylene vinylene) (PPV) polymers; spiro compounds; polyfluorene, rubrene, etc., but are not limited thereto.

[0193] The above-mentioned light-emitting layer may include a host material and a dopant material as described above. The host material may also include an aromatic fused ring derivative or a heterocyclic compound. Specifically, as an aromatic fused ring derivative, there are anthracene derivatives, pyrene derivatives, naphthalene derivatives, pentacene derivatives, phenanthrene compounds, fluoranthene compounds, etc., as heterocyclic compounds, there are carbazole derivatives, dibenzofuran derivatives, ladder-type furan compounds, etc. Pyrimidine derivatives, etc., but are not limited thereto.

[0194] As dopant materials, there are aromatic amine derivatives, styrylamine compounds, boron complexes, fluoranthene compounds, metal complexes, etc. Specifically, aromatic amine derivatives are aromatic fused ring derivatives having substituted or unsubstituted arylamino groups, such as pyrene, anthracene, Styrylamine compounds are compounds in which at least one arylvinyl group is substituted on a substituted or unsubstituted arylamine, and are substituted or unsubstituted with one or more substituents selected from aryl, silyl, alkyl, cycloalkyl, and arylamino groups. Specific examples include, but are not limited to, styrylamine, styryldiamine, styryltriamine, and styryltetramine. Furthermore, metal complexes include, but are not limited to, iridium complexes and platinum complexes.

[0195] In addition, the organic light-emitting device may further be provided with a hole blocking layer. Specifically, the hole blocking layer is a layer formed on the light-emitting layer, preferably provided in contact with the light-emitting layer, which improves the efficiency of the organic light-emitting device by adjusting the electron mobility and preventing the excessive migration of holes to increase the probability of hole-electron bonding. The hole blocking layer contains a hole blocking substance. As an example of such a hole blocking substance, the compound represented by the above chemical formula 1 can be used, or an azine derivative containing triazine, a triazole derivative, Compounds into which electron-withdrawing groups are introduced include, but are not limited to, oxadiazole derivatives, phenanthroline derivatives, phosphine oxide derivatives, and the like.

[0196] In addition, the electron injection and transport layer is a layer that injects electrons from the electrode and transports the received electrons to the light-emitting layer while acting as an electron transport layer and an electron injection layer, and is formed on the light-emitting layer or the hole blocking layer. Such an electron injection and transport substance is a substance that can well receive electrons from the cathode and transfer them to the light-emitting layer, and a substance with a large electron mobility is suitable. As an example of a specific electron injection and transport substance, a compound represented by the above chemical formula 1 can be used, or an Al complex of 8-hydroxyquinoline, a complex containing Alq3, an organic free radical compound, a hydroxyflavone-metal complex, a triazine derivative, etc. can be used, but not limited thereto. Alternatively, it can also be combined with fluorenone, anthraquinone dimethane, diphenoquinone, thiopyran dioxide, Azoles, Oxadiazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenylene methane, anthrone, and the like, as well as their derivatives, metal coordination compounds, or nitrogen-containing five-membered ring derivatives, are used together, but are not limited thereto.

[0197] The electron injection and transport layer can also be formed as a separate layer such as an electron injection layer and an electron transport layer. In this case, the electron transport layer is formed on the light-emitting layer or the hole blocking layer, and as the electron transport material contained in the electron transport layer, the electron injection and transport material can be used. In addition, the electron injection layer is formed on the electron transport layer, and as the electron injection material contained in the electron injection layer, LiF, NaCl, CsF, Li2O, BaO, fluorenone, anthraquinone dimethane, diphenoquinone, thiopyran dioxide, Azoles, Oxadiazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenylmethane, anthrone, etc. and their derivatives, metal coordination compounds and nitrogen-containing five-membered ring derivatives, etc.

[0198] Examples of the metal coordination compounds include, but are not limited to, 8-hydroxyquinolinato lithium, bis(8-hydroxyquinolinato)zinc, bis(8-hydroxyquinolinato)copper, bis(8-hydroxyquinolinato)manganese, tris(8-hydroxyquinolinato)aluminum, tris(2-methyl-8-hydroxyquinolinato)aluminum, tris(8-hydroxyquinolinato)gallium, bis(10-hydroxybenzo[h]quinolinato)beryllium, bis(10-hydroxybenzo[h]quinolinato)zinc, bis(2-methyl-8-quinolinato)gallium chloride, bis(2-methyl-8-quinolinato)(o-cresol)gallium, bis(2-methyl-8-quinolinato)(1-naphthol)aluminum, and bis(2-methyl-8-quinolinato)(2-naphthol)gallium.

[0199] The organic light emitting device according to the present invention may be a top emission type, a bottom emission type, or a bi-directional emission type depending on the materials used.

[0200] In addition, the compound represented by the above Chemical Formula 1 may be included in an organic solar cell or an organic transistor in addition to being included in an organic light-emitting device.

[0201] The preparation of the compound represented by the above Chemical Formula 1 and the organic light-emitting device containing the same is specifically described in the following examples. However, the following examples are for illustrating the present invention, and the scope of the present invention is not limited thereto.

[0202] Preparation Example 1: Preparation of Compound 1

[0203]

[0204] Under a nitrogen atmosphere, in a 500 mL round-bottom flask, 6-bromo-1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene (5.55 g, 20.79 mmol) and compound a-1 (13.42 g, 22.87 mmol) were completely dissolved in 240 mL of tetrahydrofuran. A 2M aqueous potassium carbonate solution (120 mL) was then added, followed by tetrakis(triphenylphosphine)palladium (0.71 g, 0.61 mmol). The mixture was heated and stirred for 3 hours. The temperature was lowered to room temperature, the aqueous layer was removed, dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and recrystallized from 250 mL of tetrahydrofuran to produce compound 1 (7.65 g, 57%).

[0205] MS[M+H] + =648

[0206] Preparation Example 2: Preparation of Compound 2

[0207]

[0208] Under a nitrogen atmosphere, compound 6,7-dibromo-1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene (4.68 g, 13.53 mmol) and compound a-2 (12.94 g, 29.76 mmol) were completely dissolved in 240 mL of tetrahydrofuran in a 500 mL round-bottom flask. A 2M aqueous potassium carbonate solution (120 mL) was then added, followed by tetrakis(triphenylphosphine)palladium (0.94 g, 0.81 mmol). The mixture was heated and stirred for 3 hours. The temperature was lowered to room temperature, the aqueous layer was removed, dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and recrystallized from 250 mL of ethyl acetate to produce compound 2 (8.11 g, 75%).

[0209] MS[M+H] + =804

[0210] Preparation Example 3: Preparation of Compound 3

[0211]

[0212] Under a nitrogen atmosphere, compound 6,7-dibromo-1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene (4.89 g, 14.13 mmol) and compound a-3 (13.46 g, 31.09 mmol) were completely dissolved in 240 mL of tetrahydrofuran in a 500 mL round-bottom flask. A 2M aqueous potassium carbonate solution (120 mL) was then added, followed by tetrakis(triphenylphosphine)palladium (0.98 g, 0.85 mmol). The mixture was heated and stirred for 5 hours. The temperature was lowered to room temperature, the aqueous layer was removed, dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and recrystallized from 270 mL of tetrahydrofuran to produce compound 3 (6.88 g, 61%).

[0213] MS[M+H] + =802

[0214] Preparation Example 4: Preparation of Compound 4

[0215]

[0216] Under a nitrogen atmosphere, compound 5,8-dibromo-1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene (5.14 g, 14.86 mmol) and compound a-2 (14.22 g, 32.68 mmol) were completely dissolved in 240 mL of tetrahydrofuran in a 500 mL round-bottom flask. A 2M aqueous potassium carbonate solution (120 mL) was then added, followed by tetrakis(triphenylphosphine)palladium (1.03 g, 0.89 mmol). The mixture was heated and stirred for 4 hours. The temperature was lowered to room temperature, the aqueous layer was removed, dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and recrystallized from 250 mL of tetrahydrofuran to produce compound 4 (7.23 g, 61%).

[0217] MS[M+H] + =804

[0218] Preparation Example 5: Preparation of Compound 5

[0219]

[0220] Under a nitrogen atmosphere, compound 6,7-dibromo-1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene (5.33 g, 15.40 mmol) and compound a-4 (14.74 g, 33.89 mmol) were completely dissolved in 240 mL of tetrahydrofuran in a 500 mL round-bottom flask. A 2M aqueous potassium carbonate solution (120 mL) was added, followed by tetrakis(triphenylphosphine)palladium (1.07 g, 0.92 mmol), and the mixture was heated and stirred for 5 hours. The temperature was lowered to room temperature, the aqueous layer was removed, dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and recrystallized from 250 mL of tetrahydrofuran to produce compound 5 (8.22 g, 66%).

[0221] MS[M+H] + =804

[0222] Preparation Example 6: Preparation of Compound 6

[0223]

[0224] Under a nitrogen atmosphere, compound 6-bromo-1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene (6.77 g, 25.36 mmol) and compound a-5 (16.37 g, 27.89 mmol) were completely dissolved in 240 mL of tetrahydrofuran. A 2M aqueous potassium carbonate solution (120 mL) was added, followed by tetrakis(triphenylphosphine)palladium (0.88 g, 0.76 mmol), and the mixture was heated and stirred for 5 hours. The temperature was lowered to room temperature, the aqueous layer was removed, dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and recrystallized from 240 mL of ethyl acetate to produce compound 6 (12.27 g, 75%).

[0225] MS[M+H] + =648

[0226] Preparation Example 7: Preparation of Compound 7

[0227]

[0228] Under a nitrogen atmosphere, in a 500 mL round-bottom flask, compound 5,7-dibromo-1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene (5.77 g, 16.68 mmol) and compound a-6 (15.92 g, 36.69 mmol) were completely dissolved in 240 mL of tetrahydrofuran. A 2M aqueous potassium carbonate solution (120 mL) was then added, followed by tetrakis(triphenylphosphine)palladium (1.16 g, 1.01 mmol). The mixture was heated and stirred for 5 hours. The temperature was lowered to room temperature, the aqueous layer was removed, dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and recrystallized from 250 mL of tetrahydrofuran to produce compound 7 (8.88 g, 66%).

[0229] MS[M+H] + =802

[0230] Preparation Example 8: Preparation of Compound 8

[0231]

[0232] Under a nitrogen atmosphere, compound 5,6-dibromo-1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene (6.11 g, 17.66 mmol) and compound a-2 (16.90 g, 38.85 mmol) were completely dissolved in 240 mL of tetrahydrofuran in a 500 mL round-bottom flask. A 2M aqueous potassium carbonate solution (120 mL) was then added, followed by tetrakis(triphenylphosphine)palladium (1.22 g, 1.02 mmol). The mixture was heated and stirred for 5 hours. The temperature was lowered to room temperature, the aqueous layer was removed, dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and recrystallized from 230 mL of tetrahydrofuran to produce compound 8 (7.14 g, 50%).

[0233] MS[M+H] + =804

[0234] Preparation Example 9: Preparation of Compound 9

[0235]

[0236] Under a nitrogen atmosphere, in a 500 mL round-bottom flask, compound 6-bromo-1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene (6.67 g, 24.98 mmol) and compound a-7 (19.26 g, 27.48 mmol) were completely dissolved in 240 mL of tetrahydrofuran. A 2M aqueous potassium carbonate solution (120 mL) was then added, followed by tetrakis(triphenylphosphine)palladium (0.87 g, 0.75 mmol), and the mixture was heated and stirred for 5 hours. The temperature was lowered to room temperature, the aqueous layer was removed, dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and recrystallized from 240 mL of tetrahydrofuran to produce compound 9 (10.17 g, 53%).

[0237] MS[M+H] + =763

[0238] Preparation Example 10: Preparation of Compound 10

[0239]

[0240] Under a nitrogen atmosphere, in a 500 mL round-bottom flask, compound 2,2'-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphthalene-2,3-diyl)bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane) (3.83 g, 8.69 mmol) and compound a-8 (7.11 g, 19.32 mmol) were completely dissolved in 240 mL of tetrahydrofuran. A 2M aqueous potassium carbonate solution (120 mL) was then added, followed by tetrakis(triphenylphosphine)palladium (0.67 g, 0.58 mmol), and the mixture was heated and stirred for 3 hours. The temperature was lowered to room temperature, the aqueous layer was removed, dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and recrystallized from 270 mL of ethyl acetate to produce compound 10 (8.92 g, 54%).

[0241] MS[M+H] + =852

[0242] Preparation Example 11: Preparation of Compound 11

[0243]

[0244] Under a nitrogen atmosphere, in a 500 mL round-bottom flask, compound 2,2'-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphthalene-1,4-diyl)bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane) (3.84 g, 8.74 mmol) and compound a-9 (6.95 g, 19.41 mmol) were completely dissolved in 240 mL of tetrahydrofuran. A 2M aqueous potassium carbonate solution (120 mL) was then added, followed by tetrakis(triphenylphosphine)palladium (0.67 g, 0.58 mmol), and the mixture was heated and stirred for 3 hours. The temperature was lowered to room temperature, the aqueous layer was removed, dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and recrystallized from 250 mL of tetrahydrofuran to produce compound 11 (10.11 g, 63%).

[0245] MS[M+H] + =831

[0246] Example 1-1

[0247] ITO (indium tin oxide) The thickness of the glass substrate coated with a film is placed in distilled water dissolved with a detergent and washed with ultrasonic waves. At this time, the detergent uses Fischer Co. products, and the distilled water uses distilled water filtered twice by a filter manufactured by Millipore Co. After the ITO was washed for 30 minutes, ultrasonic washing was performed twice with distilled water. After the distilled water washing is completed, ultrasonic washing is performed and dried with a solvent of isopropyl alcohol, acetone, and methanol, and then the substrate is transported to a plasma cleaning machine. In addition, after the above-mentioned substrate is cleaned for 5 minutes, the substrate is transported to a vacuum deposition machine.

[0248] On the ITO transparent electrode prepared as the anode, the following compound HI1 and the following compound HI2 were added in a ratio of 98:2 (molar ratio). A hole injection layer was formed by thermal vacuum deposition of a thickness of 1000 nm. On the hole injection layer, a compound represented by the following chemical formula HT1 was deposited. Then, a hole transport layer is formed by vacuum evaporation. An electron suppression layer was formed by vacuum deposition of an EB1 compound.

[0249] Next, on the electron suppression layer, a film having a thickness of A compound represented by the following chemical formula BH and a compound represented by the following chemical formula BD were vacuum deposited at a weight ratio of 25:1 to form a light-emitting layer.

[0250] On the above-mentioned light-emitting layer, the film thickness is The compound represented by Compound 1 prepared in Preparation Example 1 was vacuum-deposited to form a hole blocking layer. Next, a compound represented by the following chemical formula ET1 and a compound represented by the following chemical formula LiQ were vacuum-deposited on the hole blocking layer at a weight ratio of 1:1, thereby forming a hole blocking layer. The electron injection and transport layer is formed with a thickness of The thickness of the aluminum The cathode is formed by vapor deposition to a thickness of .

[0251]

[0252]

[0253] In the above process, the evaporation rate of organic matter is maintained at Lithium fluoride at the cathode maintains The evaporation speed of aluminum is maintained The evaporation speed is 2×10 -7 ~5×10 -6 The organic light-emitting device is thus produced.

[0254] Example 1-2 to Example 1-11

[0255] An organic light-emitting device was produced by the same method as in Example 1-1, except that the compounds listed in Table 1 below were used instead of the compounds in Production Example 1. The structures of the compounds used in the above examples are shown below.

[0256]

[0257] Comparative Examples 1-1 to 1-3

[0258] An organic light-emitting device was manufactured by the same method as in Example 1-1, except that the compounds described in Table 1 below were used instead of the compounds in Preparation Example 1. The structures of HB1, HB2, and HB3 used in Table 1 below are shown below.

[0259]

[0260] Experimental Example 1

[0261] When current was applied to the organic light-emitting devices produced in the above examples and comparative examples, voltage, efficiency, color coordinates, and lifetime were measured. The results are shown in Table 1. T95 refers to the time required for luminance to decrease to 95% from the initial luminance (1600 nits).

[0262] [Table 1]

[0263]

[0264] As shown in Table 1, the organic light-emitting device using the compound of the present invention as a hole-blocking layer exhibits superior characteristics in terms of driving voltage, luminous efficiency, and lifespan compared to the organic light-emitting device of the comparative example.

[0265] Specifically, the organic light-emitting devices of the above embodiments are compared with the organic light-emitting devices of Comparative Example 1-1 using the HB1 compound having a 9,9,10,10-tetramethyl-9,10-dihydroanthracene core and the organic light-emitting devices of Comparative Examples 1-2 and 1-3 using the HB2 and HB3 compounds having a 10,10-dimethyl-10H-spiro[anthracene-9,9'-fluorene] core, respectively. It can be confirmed that the organic light-emitting devices have lower driving voltages while showing improved efficiency and significantly longer lifespan.

[0266] Explanation of symbols

[0267] 1: Substrate 2: Anode

[0268] 3: Hole transport layer 4: Light-emitting layer

[0269] 5: Electron injection and transport layer 6: Cathode

[0270] 7: Hole injection layer 8: Electron suppression layer

[0271] 9: Hole blocking layer.

Claims

1. A compound represented by the following chemical formula 1: Chemical formula 1 In the chemical formula 1, R is independently C substituted or unsubstituted with deuterium 1-10 alkyl, One or two of R1 to R4 are substituents represented by the following Chemical Formula 2, and R1 to R4 that are not substituents represented by the following Chemical Formula 2 are each independently hydrogen or deuterium, Chemical formula 2 In the chemical formula 2, X1 to X3 are each independently N or CH, but at least one of X1 to X3 is N, L1 to L3 are each independently a single bond, or a C substituted or unsubstituted deuterium 6-20 arylene groups, n is 1 or 2, Ar1 and Ar2 are each independently C 6-20 aryl, dibenzofuranyl or dibenzothiophenyl, wherein Ar1 and Ar2 are substituted or unsubstituted by one or more substituents selected from deuterium, methyl, ethyl, propyl, butyl and phenyl.

2. The compound according to claim 1, wherein R are all the same.

3. The compound according to claim 2, wherein R is methyl.

4. The compound according to claim 1, wherein X1 is N, X2 and X3 are CH; or X2 is N, X1 and X3 are CH; or X1 and X2 are N, and X3 is CH; or X2 and X3 are N, and X1 is CH; or X1 to X3 are all N.

5. The compound according to claim 1, wherein L1 and L2 are each independently a single bond, a phenylene group or a naphthylene group.

6. The compound according to claim 1, wherein L3 is a single bond, a phenylene group, a naphthylene group or a biphenyldiyl group.

7. The compound according to claim 1, wherein Ar1 and Ar2 may be substituted or unsubstituted by one or more substituents selected from the group consisting of deuterium, methyl, ethyl, isopropyl, tert-butyl and phenyl.

8. The compound according to claim 1, wherein Ar1 and Ar2 are each independently a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a phenanthryl group, a 9,9-dimethylfluorenyl group, a 9,9-diphenylfluorenyl group, a dibenzofuranyl group or a dibenzothiophenyl group.

9. The compound according to claim 8, wherein Ar1 and Ar2 are each independently any one selected from the following:

10. The compound according to claim 1, wherein The compound is represented by any one of the following chemical formulas 1-1 to 1-6: Chemical formula 1-1 Chemical formula 1-2 Chemical formula 1-3 Chemical formula 1-4 Chemical formula 1-5 Chemical formula 1-6 In the chemical formulas 1-1 to 1-6, X1 to X3, L1 to L3, n, Ar1 and Ar2 are the same as defined in claim 1.

11. The compound according to claim 1, wherein The compound is any one selected from the following compounds:

12. An organic light-emitting device, wherein: include: a first electrode, a second electrode disposed opposite to the first electrode, and one or more organic layers disposed between the first electrode and the second electrode, wherein one or more of the organic layers comprises the compound according to any one of claims 1 to 11, and The organic layer containing the compound is a hole blocking layer or an electron injection and transport layer.

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