Light-emitting element

Abstract

The invention relates to a light-emitting element. A light-emitting element according to an embodiment includes a first electrode, two or more light-emitting cells on the first electrode, and a second electrode on the two or more light-emitting cells, in which the second electrode includes silver-lithium (Ag-Li), and a top light-emitting cell among the two or more light-emitting cells includes ytterbium, and which includes any one selected from the group consisting of an electron injection layer including ytterbium and an electron injection layer including a metal doped in a compound represented by Formula 1 below. Formula 1 # imgabs0 #

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a light-emitting element and a display device including the light-emitting element. Background Art

[0002] A light-emitting element is a device that converts electrical energy into light energy.

[0003] Embodiments of such a light-emitting element include an organic light-emitting element including an organic material in a light-emitting layer and a quantum dot light-emitting element including quantum dots in a light-emitting layer.

[0004] The light-emitting element may include a first electrode and a second electrode overlapping each other, and a hole transport region, a light-emitting layer, and an electron transport region between the first electrode and the second electrode.

[0005] Holes injected from the first electrode move through the hole transport region to the light-emitting layer, and electrons injected from the second electrode move through the electron transport region to the light-emitting layer.

[0006] The holes and electrons recombine in the light-emitting layer to generate excitons.

[0007] When the excitons change from an excited state to a ground state, light is generated. Summary of the Invention

[0008] Embodiments of the present disclosure improve the luminous efficiency and lifespan of the light-emitting element and solve the problem of pixel shrinkage.

[0009] A light-emitting element according to an embodiment includes a first electrode, two or more light-emitting units on the first electrode, and a second electrode on the two or more light-emitting units, wherein the second electrode includes silver-lithium (Ag-Li), and the top light-emitting unit among the two or more light-emitting units includes any one of an electron injection layer including ytterbium and an electron injection layer including a metal-doped compound represented by the following Formula 1 (for example, the metal doped in the compound represented by Formula 1 may form a complex or compound by bonding with a nitrogen atom in the compound represented by Formula 1).

[0010] Formula 1

[0011]

[0012] The metal doped in the compound represented by Formula 1 may include Li (for example, the metal doped in the compound represented by Formula 1 such as Li may form a complex or compound by bonding with a nitrogen atom in the compound represented by Formula 1).

[0013] Based on 100% by volume of the second electrode, the amount of lithium contained in the second electrode may be 50% by volume or less.

[0014] The thickness of the second electrode may be from 80 angstroms to 140 angstroms.

[0015] The second electrode may be a single layer.

[0016] Two or more light-emitting units may include a first light-emitting unit, a second light-emitting unit, a third light-emitting unit, and a fourth light-emitting unit stacked in sequence.

[0017] Two or more light-emitting units may emit different lights (e.g., may emit two or more lights each having a different wavelength).

[0018] The first to third light-emitting units may emit blue light, and the fourth light-emitting unit may emit green light.

[0019] The light-emitting element according to an embodiment includes a first electrode, two or more light-emitting units on the first electrode, and a second electrode on the two or more light-emitting units, and the second electrode includes: a first sub-electrode including silver-magnesium (Ag-Mg) and a second sub-electrode including silver-lithium (Ag-Li).

[0020] The light-emitting unit at the top among the two or more light-emitting units may include any one selected from an electron injection layer including ytterbium and an electron injection layer including a metal-doped compound represented by the following formula 1 (e.g., the metal doped in the compound represented by formula 1 may form a complex or compound by bonding with a nitrogen atom in the compound represented by formula 1).

[0021] Formula 1

[0022]

[0023] The metal doped in the compound represented by formula 1 may include Li (e.g., the metal such as Li doped in the compound represented by formula 1 may form a complex or compound by bonding with a nitrogen atom in the compound represented by formula 1).

[0024] The first sub-electrode may include silver and magnesium in a volume ratio of 99:1 to 50:50.

[0025] The second sub-electrode may include silver and lithium in a volume ratio of 99:1 to 50:50.

[0026] The thickness of the second electrode may be 200 angstroms or less.

[0027] The thickness ratio of the first sub-electrode to the second sub-electrode may be 1:9 to 9:1.

[0028] Two or more light-emitting units may include a first light-emitting unit, a second light-emitting unit, a third light-emitting unit, and a fourth light-emitting unit stacked in sequence.

[0029] Two or more light-emitting units may emit different lights (e.g., may emit two or more lights each having a different wavelength).

[0030] The first to third light-emitting units may emit blue light, and the fourth light-emitting unit may emit green light.

[0031] The display device according to an embodiment may include the above-described light-emitting element.

[0032] According to an embodiment, a light-emitting element and a display device including the light-emitting element that improve the light-emitting efficiency and lifespan of the light-emitting element and solve the problem of pixel shrinkage may be provided. Description of the Drawings

[0033] The accompanying drawings, together with the specification, illustrate embodiments of the subject matter of the present disclosure and, together with the description, are used to explain the principles of the embodiments of the subject matter of the present disclosure.

[0034] Figures 1 to 3 Each is a cross-sectional view showing a stacked structure of a light-emitting element according to an embodiment.

[0035] Figure 4 Is an exploded perspective view of a display device according to an embodiment.

[0036] Figure 5 Is a schematic cross-sectional view of a display panel according to an embodiment.

[0037] Figure 6 、 Figure 7 and Figure 8 Show experimental results according to an embodiment and a comparative example.

[0038] Description of Reference Numerals

[0039] EL1, EL2, EL3, EL4: Light-emitting units

[0040] EIL: Electron injection layer

[0041] E2: Second electrode

[0042] E2-1: First sub-electrode

[0043] E2-2: Second sub-electrode Detailed Description of Embodiments

[0044] Hereinafter, various embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings so that those skilled in the art can easily implement the embodiments of the present disclosure.

[0045] The subject matter of the present disclosure may be implemented in many different forms and is not limited to the embodiments described herein.

[0046] To clearly explain the subject matter of the present disclosure, descriptions of parts not relevant to the description may be omitted, and throughout the specification, the same reference numerals are provided for the same or similar components.

[0047] In addition, for convenience of explanation, the dimensions (e.g., thickness) of each component shown in the drawings may be arbitrarily shown, and thus, the present disclosure is not necessarily limited to the dimensions (e.g., thickness) shown.

[0048] In the drawings, the thickness may be enlarged to clearly represent various layers and regions.

[0049] In the drawings, for convenience of explanation, the thicknesses of some layers and regions may be enlarged.

[0050] In addition, when a component of a layer, film, region, or plate is referred to as being "on" or "above" another component, this includes not only the case where it is "directly on" the other component, but also the case where there is another component therebetween.

[0051] Conversely, when a component is referred to as being "on top of" or "directly on" another component, it means that there are no other components therebetween.

[0052] In addition, being "on" or "above" a reference component means being above or below the reference component, and does not necessarily mean being "on" or "above" the reference component in the direction opposite to gravity.

[0053] In addition, throughout the specification, when a component is referred to as "including" certain components, this means that it may further include other components, rather than excluding other components, unless specifically stated to the contrary.

[0054] In addition, throughout the specification, when referring to "in a plane", this means the case of observing the target part from above, and when referring to "in a cross-section", this means the case of vertically cutting the target part and observing the cross-section from the side.

[0055] Hereinafter, reference will be made to Figures 1 to 3 describe a light-emitting element according to an embodiment.

[0056] Figures 1 to 3 Cross-sectional views each showing a stacked structure of a light-emitting element according to an embodiment are shown.

[0057] First, with reference to Figure 1 , the light-emitting element 1 may include a first electrode E1, a second electrode E2, and a light-emitting unit EL between the first electrode E1 and the second electrode E2.

[0058] The light-emitting element 1 according to an embodiment may be a top-emission type (or kind).

[0059] In this case, the first electrode E1 may be an anode, and the second electrode E2 may be a cathode, but the present disclosure is not limited thereto.

[0060] The light-emitting element 1 according to an embodiment of the present disclosure may be a bottom-emitting type (or kind).

[0061] In this case, the first electrode E1 may be a cathode, and the second electrode E2 may be an anode.

[0062] In an embodiment, the light-emitting element 1 includes a first electrode E1 having reflectivity and a transparent or semi-transparent second electrode E2, so that the light-emitting element 1 can emit light from the first electrode E1 to the second electrode E2.

[0063] Hereinafter, a case where the light-emitting element 1 is a top-emitting type (or kind) will be described.

[0064] For example, the first electrode E1 may be formed by providing a material for the first electrode E1 on the upper portion of the substrate by using a deposition method and / or a sputtering method.

[0065] When the first electrode E1 is an anode, the material for the first electrode E1 may be selected from materials having a high work function to facilitate hole injection.

[0066] The first electrode E1 may be a reflective electrode, a transmissive-reflective electrode, or a transmissive electrode.

[0067] In order to form the first electrode E1 that may be a transmissive electrode, the material for the first electrode E1 may be indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO2), zinc oxide (ZnO), or any combination of the foregoing, but is not limited thereto.

[0068] In an embodiment, in order to form the first electrode E1 that may be a transmissive-reflective electrode or a reflective electrode, the material for the first electrode E1 may be magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), or any combination thereof, but is not limited thereto.

[0069] The first electrode E1 may have a single-layer structure or a multi-layer structure having a plurality of layers.

[0070] For example, the first electrode E1 may have a three-layer structure of ITO / Ag / ITO, but is not limited thereto.

[0071] The light-emitting unit EL is on the first electrode E1.

[0072] The light-emitting element 1 according to an embodiment may include at least one light-emitting unit EL.

[0073] In an embodiment, the light-emitting element 1 may include m light-emitting units EL.

[0074] In addition, the light-emitting element 1 according to the embodiment may include m - 1 charge generation layers between adjacent light-emitting units EL. For example, when m is 4, the light-emitting element 1 according to the embodiment may include three charge generation layers CGL1, CGL2, and CGL3.

[0075] The light-emitting element 1 according to the embodiment includes a first charge generation layer CGL1 between the first light-emitting unit EL1 and the second light-emitting unit EL2, a second charge generation layer CGL2 between the second light-emitting unit EL2 and the third light-emitting unit EL3, and a third charge generation layer CGL3 between the third light-emitting unit EL3 and the fourth light-emitting unit EL4.

[0076] This specification illustrates an embodiment including four light-emitting units EL1, EL2, EL3, and EL4 and three charge generation layers CGL1, CGL2, and CGL3, but is not limited thereto, and may be appropriately changed depending on the number of light-emitting units EL.

[0077] Each of the charge generation layers CGL1, CGL2, and CGL3 includes an n-type charge generation layer that supplies electrons to the light-emitting unit EL (for example, the charge generation layers CGL1, CGL2, and CGL3 respectively include n-type charge generation layers n-CGL1, n-CGL2, and n-CGL3) and a p-type charge generation layer that supplies holes to the light-emitting unit EL (for example, the charge generation layers CGL1, CGL2, and CGL3 respectively include p-type charge generation layers p-CGL1, p-CGL2, and p-CGL3).

[0078] In the embodiment, a buffer layer may further be between the n-type charge generation layer n-CGL1 and the p-type charge generation layer p-CGL1, between the n-type charge generation layer n-CGL2 and the p-type charge generation layer p-CGL2, and between the n-type charge generation layer n-CGL3 and the p-type charge generation layer p-CGL3.

[0079] When a voltage is applied, the charge generation layers CGL1, CGL2, and CGL3 may form a complex through a redox reaction to generate charges (electrons and holes).

[0080] The charge generation layers CGL1, CGL2, and CGL3 may supply the generated charges to adjacent light-emitting units EL.

[0081] The charge generation layers CGL1, CGL2, and CGL3 may double the current efficiency generated in the light-emitting unit EL and may function to control the charge balance between adjacent light-emitting units EL.

[0082] The first charge generation layer CGL1 includes a first n-type charge generation layer n-CGL1 and a first p-type charge generation layer p-CGL1.

[0083] The first n-type charge generation layer n-CGL1 may be adjacent to the first light-emitting unit EL1, and the first p-type charge generation layer p-CGL1 may be adjacent to the second light-emitting unit EL2.

[0084] The second charge generation layer CGL2 may include a second n-type charge generation layer n-CGL2 and a second p-type charge generation layer p-CGL2.

[0085] The second n-type charge generation layer n-CGL2 is adjacent to the second light-emitting unit EL2, and the second p-type charge generation layer p-CGL2 may be adjacent to the third light-emitting unit EL3.

[0086] The third charge generation layer CGL3 may include a third n-type charge generation layer n-CGL3 and a third p-type charge generation layer p-CGL3.

[0087] The third n-type charge generation layer n-CGL3 is adjacent to the third light-emitting unit EL3, and the third p-type charge generation layer p-CGL3 may be adjacent to the fourth light-emitting unit EL4.

[0088] The second electrode E2 is on the m-th light-emitting unit EL.

[0089] The second electrode E2 may be a cathode as an electron injection electrode.

[0090] In an embodiment, each light-emitting unit EL may include a light-emitting layer.

[0091] In an embodiment, the light-emitting unit EL may include at least one selected from a hole transport region and an electron transport region.

[0092] The hole transport region may include a hole injection layer, a hole transport layer, an electron blocking layer, or any combination thereof.

[0093] The electron transport region may include a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

[0094] Any suitable method commonly used in the art may be used to form the hole transport region.

[0095] For example, various suitable methods (such as vacuum deposition, spin coating, casting, LB (Langmuir-Blodgett) method, inkjet printing, laser printing, and / or laser-induced thermal imaging (LITI)) may be used to form the hole transport region.

[0096] The hole injection layer included in the hole transport region may include a hole injection material.

[0097] The hole injection material may include: phthalocyanine compounds (such as copper phthalocyanine); DNTPD (N,N'-diphenyl-N,N'-bis[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4'-diamine), m-MTDATA (4,4',4''-[tris(3-methylphenyl)phenylamino]triphenylamine), TDATA (4,4',4''-tris(N,N-diphenylamino)triphenylamine), 2-TNATA (4,4',4''-tris{N-(2-naphthyl)-N-phenylamino}triphenylamine), PEDOT / PSS (poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate)), PANI / DBSA (polyaniline / dodecylbenzenesulfonic acid), PANI / CSA (polyaniline / camphorsulfonic acid), PANI / PSS (polyaniline / poly(4-styrenesulfonate)), NPB (N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine), NPD (N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine), TPAPEK (polyether ketone containing triphenylamine), 4-isopropyl-4'-methyldiphenyliodonium [tetrakis(pentafluorophenyl)borate], HAT-CN (dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile), etc.

[0098] The hole transport layer included in the hole transport region may include a hole transport material.

[0099] The hole transport material may include carbazole derivatives (such as N-phenylcarbazole, polyvinylcarbazole), fluorene derivatives, triphenylamine derivatives (such as TPD (N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine), TCTA (4,4',4''-tris(N-carbazolyl)triphenylamine), NPB (N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine), TAPC (4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl)aniline]), HMTPD (4,4'-bis[N,N'-(3-methylphenyl)amino]-3,3'-dimethylbiphenyl), mCP (1,3-bis(N-carbazolyl)benzene), CzSi (9-(4-tert-butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole) and / or m-MTDATA (4,4',4''-[tris(3-methylphenyl)phenylamino]triphenylamine)), etc.

[0100] The thickness of the hole transport region may be about to about For example, about to about

[0101] For example, the hole injection layer may have about to about in thickness, and the hole transport layer may have a thickness of about to about in thickness.

[0102] When the thickness of the hole transport region, the thickness of the hole injection layer, and the thickness of the hole transport layer satisfy the above ranges, appropriate or satisfactory hole transport characteristics can be obtained without significantly increasing the driving voltage.

[0103] The electron blocking layer is a layer for preventing or reducing the leakage of electrons from the electron transport region to the hole transport region.

[0104] The thickness of the electron blocking layer may be about to about

[0105] For example, the electron blocking layer included in the hole transport region may include carbazole derivatives (such as N-phenylcarbazole, polyvinylcarbazole), fluorene derivatives, triphenylamine derivatives (such as TPD (N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine), TCTA (4,4',4''-tris(N-carbazolyl)triphenylamine), NPD (N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine), TAPC (4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl)aniline]), HMTPD (4,4'-bis[N,N'-(3-methylphenyl)amino]-3,3'-dimethylbiphenyl) and / or mCP).

[0106] In addition to the materials mentioned previously, the hole transport region may further include a charge generation material to improve conductivity (e.g., electrical conductivity).

[0107] The charge generation material may be uniformly or non-uniformly dispersed in the hole transport region.

[0108] The charge generation material may be, for example, a p-dopant.

[0109] The p-dopant may be one selected from quinone derivatives, metal oxides, and cyano-containing compounds, but is not limited thereto.

[0110] For example, the p-dopant may include quinone derivatives (such as tetracyanoquinodimethane (TCNQ) and / or 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanoquinodimethane (F4-TCNQ)) and / or may include metal oxides (such as tungsten oxide and / or molybdenum oxide), but is not limited thereto.

[0111] Any suitable method commonly used in the art can be used to form each layer in the electron transport region.

[0112] For example, various suitable methods (such as vacuum deposition, spin coating, casting, LB (Langmuir-Blodgett) method, inkjet printing, laser printing, and / or laser-induced thermal imaging (LITI)) can be used to form the electron transport region.

[0113] The electron injection layer included in the electron transport region may include an electron injection material.

[0114] The electron injection material includes metal halides (such as LiF, NaCl, CsF, RbCl, and / or RbI), lanthanide metals (such as Yb), metal oxides (such as Li2O and / or BaO), materials in which an organic host is doped with a metal (such as Li), and / or Liq (lithium quinolate), etc., but is not limited thereto.

[0115] The electron injection layer can also be made of a mixture of an electron transport material and an insulating organometallic salt (for example, an electrically insulating organometallic salt).

[0116] The insulating organometallic salt can be a material having a band gap of approximately 4 eV or greater.

[0117] For example, the insulating organometallic salt may include metal acetates, metal benzoates, metal acetoacetates, metal acetylacetonates, and / or metal stearates.

[0118] The electron transport layer included in the electron transport region may include an electron transport material.

[0119] The electron transport material may include triazine compounds and / or anthracene compounds.

[0120] However, the present disclosure is not limited to the above, and the electron transport material may include, for example, Alq3 (tris(8-hydroxyquinoline)aluminum), 1,3,5-tris[(3-pyridyl)-phenyl-3-yl]benzene, 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzimidazol-1-yl)phenyl)-9,10-dinaphthylanthracene, TPBi (1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene), BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), Bphen (4,7-diphenyl-1,10-phenanthroline), TAZ (3-(4-biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole), NTAZ (4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole), tBu-PBD (2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole), BAlq (bis(2-methyl-8-hydroxyquinolinato-N1,O8)-(1,1'-biphenyl-4-olato)aluminum), Bebq2 (bis(benzoquinolinato-10-hydroxy)beryllium), ADN (9,10-bis(naphthalen-2-yl)anthracene), TSPO1 (diphenyl(4-(triphenylsilyl)phenyl)phosphine oxide), TPM-TAZ (2,4,6-tris(3-(pyrimidin-5-yl)phenyl)-1,3,5-triazine), and / or mixtures thereof.

[0121] The thickness of each electron injection layer may be about to about or about to about

[0122] When the thickness of the electron injection layer satisfies the above range, appropriate or satisfactory electron injection characteristics can be obtained without significantly increasing the driving voltage.

[0123] The thickness of each electron transport layer may be about to about For example, about to about

[0124] When the thickness of the electron transport layer satisfies the above range, appropriate or satisfactory electron transport characteristics can be obtained without significantly increasing the driving voltage.

[0125] The hole blocking layer is a layer that prevents or reduces the leakage of holes from the hole transport region to the electron transport region.

[0126] The thickness of the hole blocking layer may be about to about

[0127] The hole blocking layer included in the electron transport region includes, for example, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), Bphen (4,7-diphenyl-1,10-phenanthroline), and / or T2T (2,4,6-tris([1,1'-biphenyl]-3-yl)-1,3,5-triazine), but is not limited thereto.

[0128] The light emitting layer may include one or more selected from organic compounds and semiconductor compounds, but is not limited thereto.

[0129] When the light emitting layer includes an organic compound, the light emitting element 1 may be referred to as an organic light emitting element.

[0130] The organic compound may include a host and a dopant.

[0131] The semiconductor compound may include quantum dots. For example, the light-emitting element 1 may be a quantum dot light-emitting element.

[0132] In an embodiment, the semiconductor compound may be an organic perovskite and / or an inorganic perovskite.

[0133] The thickness of the light-emitting layer may be from about 0.1 nm to about 100 nm.

[0134] For example, the thickness of the light-emitting layer may be from 15 nm to 50 nm.

[0135] In an embodiment, when the light-emitting layer emits blue light, the thickness of the blue light-emitting layer may be from 15 nm to 20 nm, and when the light-emitting layer emits green light, the thickness of the green light-emitting layer may be from 20 nm to 40 nm, and when the light-emitting layer emits red light, the thickness of the red light-emitting layer may be from 40 nm to 50 nm.

[0136] When the above ranges are satisfied, the light-emitting element 1 may exhibit excellent light-emitting characteristics without significantly increasing the driving voltage.

[0137] The light-emitting layer may include a host material and a dopant material.

[0138] The light-emitting layer may be formed by using a phosphorescent material and / or a fluorescent material as the dopant material in the host material.

[0139] The light-emitting layer may be formed by including a thermally activated delayed fluorescence (TADF) dopant in the host material.

[0140] In an embodiment, the light-emitting layer may include a quantum dot material as the light-emitting material.

[0141] The core of the quantum dot may be selected from group II-VI compounds, group III-V compounds, group IV-VI compounds, group IV elements, group IV compounds, and any combination thereof.

[0142] The color of the light emitted from the light-emitting layer may be determined by the combination of the host material and the dopant material, the type (or species) of the quantum dot material, and the size of the core.

[0143] As the host material of the light-emitting layer, any suitable material commonly used in the art may be used without specific limitation, but may include fluoranthene derivatives, pyrene derivatives, arylacetylene derivatives, anthracene derivatives, and / or fluorene derivatives, and may be selected from perylene derivatives, 1,2-benzophenanthrene derivatives, etc.

[0144] Example embodiments include pyrene derivatives, perylene derivatives, and / or anthracene derivatives.

[0145] As a dopant material for the light-emitting layer, any suitable material commonly used in the art can be used, and there is no specific limitation, but it includes styryl derivatives (for example, 1,4-bis[2-(3-N-ethylcarbazolyl)vinyl]benzene (BCzVB), 4-(di-p-tolylamino)-4'-[(di-p-tolylamino)styryl]stilbene (DPAVB), N-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl)naphthalen-2-yl)vinyl)phenyl)-N-phenylaniline (N-BDAVBi)), perylene and its derivatives (for example, 2,5,8,11-tetra-tert-butylperylene (TBP)), pyrene and its derivatives (for example, 1,1'-dipyrene, 1,4-dipyrenylbenzene, 1,4-bis(N,N-diphenylamino)pyrene), N1,N6-di(naphthalen-2-yl)-N1,N6-diphenylpyrene-1,6-diamine), etc.).

[0146] The light-emitting element 1 according to the embodiment may include a light-emitting unit EL that emits different lights (for example, lights having different wavelengths from each other).

[0147] At least one of the plurality of light-emitting units EL may emit light of a first color, and at least one of the remaining light-emitting units EL may emit light of a second color.

[0148] The first color and the second color may be different from each other.

[0149] For example, the light-emitting element 1 may include a first light-emitting unit EL1, a second light-emitting unit EL2, and a third light-emitting unit EL that emit blue light, and a fourth light-emitting unit EL4 that emits green light.

[0150] According to the embodiment, the capping layer CPL may be on the second electrode E2.

[0151] According to the embodiment, the above light-emitting element 1 may include the following materials, but is not limited thereto.

[0152]

[0153] Hereinafter, with reference to Figure 2 and Figure 3 ,the electron injection layer and the second electrode included in the fourth light-emitting unit in the light-emitting element according to the embodiment will be described.

[0154] The description of the components that are the same as the above components may not be repeated here.

[0155] First, with reference to Figure 2, the light-emitting element 1 according to the embodiment includes a first electrode E1, a first light-emitting unit EL1, a first charge generation layer CGL1, a second light-emitting unit EL2, a second charge generation layer CGL2, a third light-emitting unit EL3, a third charge generation layer CGL3, a fourth light-emitting unit EL4, and a second electrode E2.

[0156] In the embodiment, the fourth light-emitting unit EL4 may include a hole transport region, a light-emitting layer, and an electron transport region.

[0157] The first to third light-emitting units EL1, EL2, and EL3 according to the embodiment may emit blue light, and the fourth light-emitting unit EL4 may emit green light.

[0158] In the embodiment, the fourth light-emitting unit EL4 is shown as being divided into an electron injection layer EIL and the remaining stacked structure EL4a.

[0159] The fourth light-emitting unit EL4 may include an electron injection layer EIL including a lanthanide metal, for example, an electron injection layer EIL including ytterbium (Yb).

[0160] However, the electron injection layer EIL is not limited thereto, and a metal having a work function value of less than 3.7 eV may be used instead.

[0161] In the embodiment, the fourth light-emitting unit EL4 may include a compound represented by the following formula 1 and a metal doped into the compound represented by the following formula 1.

[0162] In the embodiment, the metal doped into the compound represented by the following formula 1 may be lithium (Li) (for example, Li may be bonded to a nitrogen atom in the compound represented by the following formula 1).

[0163] Formula 1

[0164]

[0165] The second electrode E2 may be on the fourth light-emitting unit EL4.

[0166] The second electrode E2 according to the embodiment may include silver-lithium (Ag-Li).

[0167] Relative to the second electrode E2 (for example, based on 100 vol% of the second electrode E2), the lithium (Li) contained in the second electrode E2 may be 50 vol% or less.

[0168] The second electrode E2 is not limited to the foregoing, and the foregoing silver (Ag) may be replaced with a metal having a conductivity of 1×10 7 S / m or greater, for example, the foregoing silver (Ag) may be replaced with gold (Ag), copper (Cu), aluminum (Al), etc.

[0169] In an embodiment, lithium (Li) can be replaced with a hygroscopic metal (e.g., magnesium (Mg), potassium (K), cesium (Cs), rubidium (Rb), calcium (Ca), ytterbium (Yb), and / or samarium (Sm)).

[0170] The thickness of the second electrode E2 can be from 80 angstroms to 140 angstroms.

[0171] The light-emitting element 1 according to an embodiment may include: an electron injection layer EIL including ytterbium (Yb) and a second electrode E2 including silver-lithium (Ag-Li).

[0172] In an embodiment, the light-emitting element 1 according to an embodiment may include: an electron injection layer EIL in which the compound represented by Formula 1 above is doped with lithium (Li) and a second electrode E2 including silver-lithium (Ag-Li).

[0173] Lithium (Li) contained in the second electrode E2 can be used to collect moisture, thereby preventing or reducing pixel shrinkage.

[0174] In an embodiment, since the light absorption rate of lithium (Li) is relatively low, the light-emitting efficiency can also be increased.

[0175] The light-emitting element 1 according to an embodiment may have improved light-emitting efficiency and lifespan.

[0176] Hereinafter, reference will be made to Figure 3 Describe the light-emitting element according to an embodiment.

[0177] The description of the configuration identical to that of the above light-emitting element 1 may not be repeated here.

[0178] Reference Figure 3 , the light-emitting element 1 according to an embodiment includes the above-described first electrode E1, first light-emitting unit EL1, first charge generation layer CGL1, second light-emitting unit EL2, second charge generation layer CGL2, third light-emitting unit EL3, third charge generation layer CGL3, fourth light-emitting unit EL4, and second electrode E2.

[0179] In an embodiment, the fourth light-emitting unit EL4 may include the above-described hole transport region, light-emitting layer, and electron transport region.

[0180] According to an embodiment, the first to third light-emitting units EL1, EL2, and EL3 may emit blue light, and the fourth light-emitting unit EL4 may emit green light.

[0181] In an embodiment, the fourth light-emitting unit EL4 is shown as being divided into an electron injection layer EIL and the remaining stacked structure EL4a, but the present disclosure is not limited thereto.

[0182] The fourth light-emitting unit EL4 may include: an electron injection layer EIL including a lanthanide metal. For example, the electron injection layer EIL may include an electron injection layer EIL including ytterbium (Yb).

[0183] However, the present disclosure is not limited to the above, and a metal having a work function value of less than 3.7 eV may be used instead.

[0184] In an embodiment, the fourth light-emitting unit EL4 may include a compound represented by the following formula 1 and a metal doped into the compound represented by the following formula 1 (for example, the metal may be bonded to a nitrogen atom of the compound represented by the following formula 1).

[0185] For example, the metal doped into the compound represented by the following formula 1 may be lithium (Li) (for example, lithium may be bonded to a nitrogen atom of the compound represented by the following formula 1).

[0186] Formula 1

[0187]

[0188] According to an embodiment, the second electrode E2 may include a first sub-electrode E2-1 and a second sub-electrode E2-2.

[0189] The first sub-electrode E2-1 may be adjacent to the fourth light-emitting unit EL4, and the second sub-electrode E2-2 may be on the first sub-electrode E2-1.

[0190] The first sub-electrode E2-1 may include silver-magnesium (Ag-Mg), and the second sub-electrode E2-2 may include silver-lithium (Ag-Li).

[0191] The first sub-electrode E2-1 may include silver and magnesium in a volume ratio of 99:1 to 50:50.

[0192] The second sub-electrode E2-2 may include silver and lithium in a volume ratio of 99:1 to 50:50.

[0193] The first sub-electrode E2-1 is not limited to the above materials, and silver (Ag) may be replaced with a metal having a conductivity of 1×10 7 S / m or greater (for example, gold (Ag), copper (Cu), aluminum (Al), etc.).

[0194] In an embodiment, magnesium (Mg) included in the first sub-electrode E2-1 may be replaced with a metal having a work function value of 3 eV or less (for example, calcium (Ca), lithium (Li), ytterbium (Yb), and / or samarium (Sm)).

[0195] The second sub-electrode E2-2 is also not limited to the above materials, and silver (Ag) may be replaced with a metal having a conductivity of 1×10 7It can be replaced with a metal having a conductivity of S / m or greater (for example, silver (Ag), copper (Cu), aluminum (Al), etc.).

[0196] In an embodiment, lithium (Li) can be replaced with a hygroscopic metal (for example, magnesium (Mg), potassium (K), cesium (Cs), rubidium (Rb), calcium (Ca), ytterbium (Yb), and / or samarium (Sm)), and can contain a metal different from the metal included in the first sub-electrode E2-1.

[0197] The total thickness of the first sub-electrode E2-1 and the second sub-electrode E2-2 can be 200 Å or less.

[0198] The thickness ratio of the first sub-electrode E2-1 to the second sub-electrode E2-2 can be from 1:9 to 9:1.

[0199] The lithium (Li) included in the second sub-electrode E2-2 can function to collect moisture, thereby preventing or reducing pixel shrinkage.

[0200] In an embodiment, since the light absorption rate of lithium (Li) is relatively low, the luminous efficiency can also be increased.

[0201] The light-emitting element 1 according to the embodiment can have improved luminous efficiency and lifespan.

[0202] When the second electrode E2 is formed only of the first sub-electrode E2-1, the magnesium contained in the second electrode E2 has a high light absorption rate, so there is a problem of reduced light output efficiency.

[0203] In addition, when the electron injection layer includes an organic host material, there are problems such as magnesium being unable to collect exhaust gas generated from the electron injection layer, resulting in pixel shrinkage.

[0204] However, according to the embodiment, the light-emitting element 1 includes the second sub-electrode E2-2 containing silver-lithium, thereby improving the luminous efficiency and lifespan of the light-emitting element 1 and reducing pixel shrinkage.

[0205] Hereinafter, a display device including the above-described light-emitting element 1 will be described.

[0206] Figure 4 is an exploded perspective view of a display device according to an embodiment, and Figure 5 is a schematic cross-sectional view of a display panel according to an embodiment.

[0207] First, referring to Figure 4 , the display device 1000 according to the embodiment can include a cover window CW, a display panel DP, and a housing HM.

[0208] The cover window CW can include an insulating panel (for example, an electrically insulating panel).

[0209] For example, the cover window CW may include glass, plastic, or any combination thereof.

[0210] The front portion of the cover window CW may define the front portion of the display device 1000.

[0211] The transmissive area TA may be an optically transparent area.

[0212] For example, the transmissive area TA may be an area having a visible light transmittance of about 90% or higher.

[0213] The blocking area CBA may define the shape of the transmissive area TA.

[0214] The blocking area CBA is adjacent to the transmissive area TA and may surround the transmissive area TA.

[0215] The blocking area CBA may be an area having a relatively low light transmittance compared to the transmissive area TA.

[0216] The blocking area CBA may include an opaque material that blocks light.

[0217] The blocking area CBA may have a set color or a predetermined color.

[0218] The blocking area CBA may be defined by a border layer provided separately from the transparent substrate that defines the transmissive area TA, or may be defined by an ink layer formed by inserting and / or coloring the transparent substrate.

[0219] The side of the display panel DP on which an image is displayed is parallel to the side defined by the first direction DR1 and the second direction DR2.

[0220] The third direction DR3 indicates the normal direction of the side on which the image is displayed, for example, the thickness direction of the display panel DP.

[0221] The front surface (or upper surface) and the rear surface (or lower surface) of each component are separated by the third direction DR3.

[0222] However, the directions indicated by the first to third directions DR1, DR2, and DR3 are relative concepts and can be converted into other directions.

[0223] The display panel DP may be a flat rigid display panel, but is not limited thereto, and may be a flexible display panel.

[0224] In an embodiment, the display panel DP may include an organic light emitting display panel.

[0225] However, the type (or kind) of the display panel DP is not limited thereto, and may include various suitable types (or kinds) of panels.

[0226] For example, the display panel DP may include a liquid crystal display panel, an electrophoretic display panel, an electro-wetting display panel, and the like.

[0227] In an embodiment, the display panel DP may include a next-generation display panel, such as a micro light-emitting diode (LED) display panel, a quantum dot light-emitting diode display panel, and / or a quantum dot organic light-emitting diode display panel.

[0228] In an embodiment, the micro-LED display panel includes light-emitting diodes sized from 10 micrometers to 100 micrometers to form each pixel.

[0229] These micro light-emitting diode display panels have at least the following characteristics: they use inorganic materials, can omit the backlight, have a fast response speed, can achieve high brightness with low power, and do not break when bent.

[0230] A quantum dot light-emitting diode display panel and / or a quantum dot organic light-emitting diode display panel can be made by attaching a film containing quantum dots and / or by forming a quantum dot light-emitting diode display panel with a material containing quantum dots.

[0231] Quantum dots are particles made of inorganic materials (such as, for example, indium and cadmium), which emit light by themselves and have a diameter of several nanometers or less, but the present disclosure is not limited thereto.

[0232] By controlling the particle size of the quantum dots, light of an appropriate or desired color can be emitted.

[0233] The quantum dot organic light-emitting diode display panel uses a blue organic light-emitting diode as a light source and can be made by attaching a film containing red quantum dots and a film containing green quantum dots on top of it and / or by depositing a material containing red quantum dots and a material containing green quantum dots to achieve a set or desired color.

[0234] The display panel DP according to an embodiment can be made of various other suitable display panels.

[0235] As Figure 4 shown, the display panel DP includes a display area DA for displaying an image and a non-display area PA adjacent to the display area DA.

[0236] The non-display area PA is an area that does not display an image.

[0237] For example, the display area DA may have a square shape, and the non-display area PA may have a shape surrounding the display area DA.

[0238] However, the shapes of the display area DA and the non-display area PA can be designed relatively, and are not limited thereto.

[0239] The housing HM provides a set or predetermined internal space.

[0240] The display panel DP is installed inside the housing HM.

[0241] In addition to the display panel DP, various suitable electronic components (such as a power supply unit, a storage device, and / or an audio input / output module) can be installed inside the housing HM.

[0242] Next, reference will be made to Figure 5 describe the display panel according to the embodiment.

[0243] Reference Figure 4 and Figure 5 , a plurality of pixels PA1, PA2, and PA3 can be on a substrate SUB corresponding to the display area DA of the display panel DP.

[0244] Each of the plurality of pixels PA1, PA2, and PA3 can include a plurality of transistors and a light-emitting element connected to the plurality of transistors.

[0245] The light-emitting element can include the light-emitting element 1 previously referred to in Figure 2 and Figure 3 described.

[0246] The above-mentioned capping layer CPL and encapsulation layer ENC can be on the plurality of pixels PA1, PA2, and PA3.

[0247] The display area DA can be protected from external air and / or moisture by the encapsulation layer ENC.

[0248] The encapsulation layer ENC can be provided integrally to overlap the entire surface of the display area DA and can be partially on the non-display area PA.

[0249] The first color conversion unit CC1, the second color conversion unit CC2, and the transmissive unit CC3 can be on the encapsulation layer ENC.

[0250] The first color conversion unit CC1 overlaps with the first pixel PA1, the second color conversion unit CC2 overlaps with the second pixel PA2, and the transmissive unit CC3 overlaps with the third pixel PA3.

[0251] The light emitted from the first pixel PA1 can pass through the first color conversion unit CC1 to provide red light LR.

[0252] The light emitted from the second pixel PA2 can pass through the second color conversion unit CC2 to provide green light LG.

[0253] The light emitted from the third pixel PA3 can pass through the transmissive unit CC3 to provide blue light LB.

[0254] Hereinafter, reference will be made to Figures 6 to 8 describe the embodiment and the comparative example.

[0255] Figures 6 to 8 show the experimental results according to the embodiments and comparative examples. Obtained by aging the sample at a constant current of 0.6 mA at room temperature for 250 hours Figures 6 to 8 experimental data. Pixel shrinkage was measured using a microscope, measuring from the outermost part of the pixel to the boundary between the bright and dark regions inside the pixel.

[0256] Figure 6 Comparative Example 1 includes an electron injection layer containing ytterbium (Yb) and a second electrode containing silver-magnesium (Ag-Mg).

[0257] In Comparative Example 1, based on 100% by volume of the second electrode, it includes 5% by volume of magnesium (Mg).

[0258] Comparative Example 2 includes: an electron injection layer in which a compound represented by Formula 1 is doped with lithium (Li) and a second electrode containing silver-magnesium (Ag-Mg).

[0259] In Comparative Example 2, based on 100% by volume of the second electrode, it includes 5% by volume of magnesium.

[0260] The embodiment is a case where the electron injection layer includes a compound represented by Formula 1 doped with lithium (Li) and the second electrode contains silver-lithium (Ag-Li).

[0261] In the embodiment, based on 100% by volume of the second electrode, it includes 10% by volume of lithium (Li).

[0262] Each second electrode according to Comparative Example 1, Comparative Example 2, and the embodiment has a thickness of 100 Å.

[0263] See together Figure 6 and Figure 7 , it can be seen that compared with Comparative Example 2, the pixel shrinkage phenomenon in the embodiment is significantly reduced. In Figure 7 , "hour" represents the elapsed time, and "μm" indicates the degree of pixel shrinkage.

[0264] Comparative Example 1 and the embodiment show similar characteristics, but it is confirmed that compared with Comparative Example 1, according to the embodiment, the pixel shrinkage phenomenon is generally reduced.

[0265] Referring to Table 1 below, Comparative Example 1 is a light-emitting element including: an electron injection layer containing ytterbium and a second electrode containing silver-magnesium, and Comparative Example 2 is a light-emitting element in which a compound represented by Formula 1 above is doped with lithium (Li), and specifically, Comparative Example 2 is a light-emitting element including: an electron injection layer in which a compound represented by Formula 1 above is doped with lithium (Li) and a second electrode made of silver-magnesium.

[0266] Embodiment 1 includes a light-emitting element having an electron injection layer including ytterbium and a second electrode including silver-lithium (Ag-Li).

[0267] In Embodiment 1, based on 100% by volume of the second electrode, 5% by volume of lithium is included.

[0268] Embodiment 2 includes a light-emitting element having an electron injection layer including ytterbium and a second electrode including silver-lithium (Ag-Li).

[0269] In Embodiment 2, based on 100% by volume of the second electrode, 10% by volume of lithium may be included.

[0270] Embodiment 3 includes a light-emitting element having an electron injection layer including ytterbium and a second electrode including silver-lithium (Ag-Li).

[0271] In Embodiment 3, based on 100% by volume of the second electrode, 20% by volume of lithium may be included.

[0272] Embodiment 4 includes a light-emitting element having an electron injection layer doped with lithium in the compound represented by the above formula 1 and a second electrode including silver-lithium (Ag-Li).

[0273] In Embodiment 4, based on 100% by volume of the second electrode, 5% by volume of lithium may be included.

[0274] Embodiment 5 includes a light-emitting element having an electron injection layer doped with lithium in the compound represented by the above formula 1 and a second electrode including silver-lithium (Ag-Li).

[0275] In Embodiment 5, based on 100% by volume of the second electrode, 10% by volume of lithium may be included.

[0276] Embodiment 6 includes a light-emitting element having an electron injection layer doped with lithium in the compound represented by the above formula 1 and a second electrode including silver-lithium (Ag-Li).

[0277] In Embodiment 6, based on 100% by volume of the second electrode, 20% by volume of lithium may be included.

[0278] Referring to Table 1, it is confirmed that the luminous efficiency of Embodiments 1 to 6 is increased by about 3% to a maximum of 15% compared to Comparative Example 1.

[0279] In addition, it is confirmed that the lifetime of the light-emitting element is also increased by about 8% to a maximum of 10%.

[0280] According to the embodiments of the present disclosure, it is confirmed that a light-emitting element can be provided that improves luminous efficiency and lifetime while reducing pixel shrinkage.

[0281] Table 1

[0282]

[0283] In Table 1 above and Tables 3 and 4 below, the percentages listed represent relative values compared to the reference.

[0284] Referring to Table 2, the comparative example is a light-emitting element including a second electrode containing silver-magnesium.

[0285] Based on 100% by volume of the second electrode, it includes 5% by volume of magnesium.

[0286] The embodiment is a light-emitting element including a second electrode containing silver-lithium.

[0287] Based on 100% by volume of the second electrode, it includes up to 20% by volume of lithium.

[0288] According to the embodiment, within the entire wavelength (λ) range, lithium has a lower light absorption rate compared to magnesium, and thus the light-emitting efficiency can be improved by the second electrode itself.

[0289] Table 2

[0290]

[0291] Referring to Table 3, Comparative Example 1 is a light-emitting element including an electron injection layer including ytterbium (Yb) and a second electrode including silver-magnesium (Ag-Mg), and Comparative Example 2 is a light-emitting element having the compound represented by Formula 1 above, and specifically, Comparative Example 2 is a light-emitting element including an electron injection layer including the compound represented by Formula 1 above doped with lithium (Li) and a second electrode including silver-magnesium (Ag-Mg).

[0292] Embodiment 7 includes: an electron injection layer including the compound represented by Formula 1 above doped with lithium (Li), a first sub-electrode including silver-magnesium (Ag-Mg) having a thickness of 10 Å, and a second electrode including a second sub-electrode including silver-lithium (Ag-Li) having a thickness of 90 Å.

[0293] Embodiment 8 includes: an electron injection layer including the compound represented by Formula 1 above doped with lithium (Li), a first sub-electrode including silver-magnesium (Ag-Mg) having a thickness of 50 Å, and a second sub-electrode including silver-lithium (Ag-Li) having a thickness of 50 Å.

[0294] Embodiment 9 includes: an electron injection layer including the compound represented by Formula 1 doped with lithium (Li), a first sub-electrode including silver-magnesium (Ag-Mg) having a thickness of 90 Å, and a second electrode including a second sub-electrode including silver-lithium (Ag-Li) having a thickness of 10 Å.

[0295] Referring to Table 3 and Figure 8 , in Embodiments 7 to 9, it was confirmed that the pixel shrinkage shape was significantly reduced compared to Comparative Example 1. In Figure 8 , "hour" represents the elapsed time, and "μm" indicates the degree of pixel shrinkage.

[0296] Referring to Table 3 and Figure 8 , it was confirmed that in Embodiments 7 to 9, the luminous efficiency was improved by about 1% to about 6% and the lifetime of the light-emitting element was increased by about 1% to about 3% compared to Comparative Example 2.

[0297] Moreover, in Embodiments 7 to 9, pixel shrinkage did not occur.

[0298] Table 3

[0299]

[0300] In Tables 3 and 4, "O" indicates that pixel shrinkage has occurred, while "X" means that no pixel shrinkage was observed.

[0301] Referring to Table 4, it was confirmed that in Embodiments 10 to 12, the luminous efficiency was increased by about 1% to about 5% and the lifetime of the light-emitting element was increased by about 1% to about 3% compared to Comparative Example 1.

[0302] Embodiment 10 includes: an electron injection layer containing ytterbium, and a second electrode including a first sub-electrode having a thickness of 10 Å and including silver-magnesium (Ag-Mg) and a second sub-electrode having a thickness of 90 Å and including silver-lithium (Ag-Li).

[0303] Embodiment 11 includes: an electron injection layer containing ytterbium, and a second electrode including a first sub-electrode having a thickness of 50 Å and containing silver-magnesium (Ag-Mg) and a second sub-electrode having a thickness of 50 Å and containing silver-lithium (Ag-Li).

[0304] Embodiment 12 includes: an electron injection layer containing ytterbium, and a second electrode including a first sub-electrode having a thickness of 90 Å and containing silver-magnesium (Ag-Mg) and a second sub-electrode having a thickness of 10 Å and containing silver-lithium (Ag-Li).

[0305] Moreover, in Embodiments 10 to 12, pixel shrinkage did not occur.

[0306] Table 4

[0307]

[0308] According to the embodiment, it was confirmed that a light-emitting element capable of reducing pixel shrinkage while improving luminous efficiency and lifetime can be provided.

[0309] Although the exemplary embodiments of the present disclosure have been described above, the scope of the present disclosure is not limited thereto, and various appropriate modifications and improvements are also possible for those skilled in the art using the basic concepts of the present disclosure defined in the claims.

Claims

1. A light emitting element, comprising: a first electrode; two or more light-emitting units on the first electrode; as well as a second electrode on the two or more light emitting units, wherein the second electrode comprises silver-lithium, and The top light emitting unit among the two or more light emitting units comprises: Any one selected from an electron injection layer including ytterbium and an electron injection layer including a compound represented by the following Formula 1 doped with a metal:

2. The light emitting element according to claim 1, wherein: The metal doped in the compound represented by Formula 1 includes Li.

3. The light emitting element according to claim 1, wherein: The amount of the lithium contained in the second electrode is 50 volume % or less based on 100 volume % of the second electrode.

4. The light emitting element according to claim 1, wherein: The second electrode has a thickness of 80 angstroms to 140 angstroms.

5. The light emitting element according to claim 1, wherein: The second electrode is a single layer.

6. The light emitting element according to claim 1, wherein: The two or more light emitting units include a first light emitting unit, a second light emitting unit, a third light emitting unit and a fourth light emitting unit stacked in sequence, The two or more light emitting units emit different lights.

7. A light emitting element, comprising: a first electrode; two or more light-emitting units on the first electrode; as well as a second electrode on the two or more light emitting units, The second electrode comprises: a first sub-electrode comprising silver-magnesium, and A second sub-electrode includes silver-lithium.

8. The light emitting element according to claim 7, wherein: The top light emitting unit among the two or more light emitting units comprises: Any one selected from an electron injection layer including ytterbium and an electron injection layer including a compound represented by the following Formula 1 doped with a metal:

9. The light emitting element according to claim 7, wherein: The metal doped in the compound represented by Formula 1 includes Li.

10. The light emitting element according to claim 7, wherein: The second electrode has a thickness of 200 angstroms or less.

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