Light emitting device and display device comprising the same

Abstract

A light-emitting element according to one embodiment includes a first electrode, a second electrode overlapping with the first electrode, and a light-emitting unit located between the first electrode and the second electrode, wherein the second electrode includes a first layer containing a first organic material located on the light-emitting unit and a metal thin film layer containing one type of metal located on the first layer, and the light-emitting unit includes a light-emitting layer, a hole transport region located between the first electrode and the light-emitting layer, and an electron transport region located between the light-emitting layer and the second electrode, and the first layer is disposed on the electron transport region.

Description

Technology Field

[0001] The present disclosure relates to a light-emitting element and a display device including the same. Background Technology

[0002] A light-emitting device is a device characterized by the conversion of electrical energy into light energy. Examples of such light-emitting devices include organic light-emitting devices that use organic materials in the light-emitting layer, and quantum dot light-emitting devices that use quantum dots in the light-emitting layer.

[0003] A light-emitting device may include a first electrode and a second electrode that overlap each other, a hole transport region located between them, a light-emitting layer, and an electron transport region. Holes injected from the first electrode move to the light-emitting layer through the hole transport region, and electrons injected from the second electrode move to the light-emitting layer through the electron transport region. Holes and electrons combine in the light-emitting layer region to generate excitons. Light is generated as excitons change from an excited state to a ground state. The problem to be solved

[0004] The embodiments are intended to provide an electrode comprising a single metal having a thin thickness. The electrode is intended to provide improved conductivity and transmittance by having excellent film quality. By providing a light-emitting element comprising the electrode, the quality of a display device comprising the light-emitting element is improved. means of solving the problem

[0005] A light-emitting element according to one embodiment includes a first electrode, a second electrode overlapping with the first electrode, and a light-emitting unit located between the first electrode and the second electrode, wherein the second electrode includes a first layer containing a first organic material located on the light-emitting unit and a metal thin film layer containing one type of metal located on the first layer, and the light-emitting unit includes a light-emitting layer, a hole transport region located between the first electrode and the light-emitting layer, and an electron transport region located between the light-emitting layer and the second electrode, and the first layer is disposed on the electron transport region.

[0006] The first organic material can form a coordination bond with the first metal.

[0007] The first layer above may include at least one of a phenanthroline group, a pyrene group, a furan group, and a thiol group.

[0008] The first layer may further include a first metal doped into the first organic material.

[0009] The first metal may further include at least one of Yb, Li, Cu, Ag, Au, Al, and Mg.

[0010] The metal of the above metal thin film layer may include any one of Ag, Au, Cu, Al, and Mg.

[0011] The second electrode may further include a holding layer located on the metal thin film layer.

[0012] The holding layer above includes a second organic material and can form a coordination bond with the metal of the metal thin film layer.

[0013] The second organic material may include at least one of a phenanthroline group, a pyrene group, a furan group, and a thiol group.

[0014] The holding layer may further include a second metal doped into the second organic material.

[0015] The second metal may further include at least one of Yb, Li, Cu, Ag, Au, Al, and Mg.

[0016] A display device according to one embodiment includes a substrate, a transistor disposed on the substrate, and a light-emitting element electrically connected to the transistor, wherein the light-emitting element includes a first electrode, a second electrode superimposed on the first electrode, and a light-emitting unit located between the first electrode and the second electrode, wherein the second electrode includes a first layer comprising a first organic material located on the light-emitting unit, and a metal thin film layer comprising a metal located on the first layer, wherein the first layer may include at least one of a phenanthroline group, a pyrene group, a furan group, and a thiol group.

[0017] The first organic material can form a coordination bond with the first metal.

[0018] The first layer may further include a first metal doped into the first organic material.

[0019] The first metal may further include at least one of Yb, Li, Cu, Ag, Au, Al, and Mg.

[0020] The metal of the above metal thin film layer may include any one of Ag, Au, Cu, Al, and Mg.

[0021] The second electrode further includes a holding layer located on the metal thin film layer, and the holding layer may include a second organic material.

[0022] The second organic material may include at least one of a phenanthroline group, a pyrene group, a furan group, and a thiol group.

[0023] The holding layer further comprises a second metal doped into the second organic material, and the second metal may further comprise at least one of Yb, Li, Cu, Ag, Au, Al, and Mg.

[0024] The thickness of the holding layer may be about 10 Angstroms to about 700 Angstroms. Effects of the invention

[0025] The embodiments are intended to provide an electrode comprising a single metal having a thin thickness. The electrode is intended to provide improved conductivity and transmittance by having excellent film quality. By providing a light-emitting element comprising the electrode, the quality of a display device comprising the light-emitting element is improved. Brief explanation of the drawing

[0026] FIG. 1 is a schematic cross-sectional view of a light-emitting element according to one embodiment. FIGS. 2 and FIGS. 3 are each cross-sectional views of a second electrode according to one embodiment. FIGS. 4, FIGS. 5, and FIGS. 6 are each cross-sectional views of a second electrode according to one embodiment. FIG. 7 is a schematic cross-sectional view of a light-emitting element according to one embodiment. FIG. 8 is an exploded perspective view of a display device according to one embodiment. FIG. 9 is a schematic cross-sectional view of a display panel according to one embodiment. FIG. 10 is a cross-sectional view of a display panel according to one embodiment. FIG. 11 is a graph showing the sheet resistance of the second electrode according to the comparative example and the embodiment. FIG. 12 is a graph showing the sheet resistance of the second electrode according to the comparative example and the embodiment. FIG. 13 is a graph showing the change in sheet resistance of the second electrode according to the comparative example and the embodiment. Specific details for implementing the invention

[0027] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0028] To clearly explain the present invention, parts unrelated to the explanation have been omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0029] Furthermore, the size and thickness of each component shown in the drawings are depicted arbitrarily for convenience of explanation, and thus the present invention is not necessarily limited to what is illustrated. Thicknesses have been enlarged in the drawings to clearly represent various layers and regions. Additionally, for convenience of explanation, the thickness of some layers and regions has been exaggerated in the drawings.

[0030] Furthermore, when it is said that a part, such as a layer, membrane, region, or plate, is "on" or "on" another part, this includes not only the case where it is "directly above" the other part, but also the case where there is another part in between. Conversely, when it is said that a part is "directly above" another part, it means that there is no other part in between. Also, saying that a part is "on" or "on" a reference part means that it is located above or below the reference part, and does not necessarily mean that it is located "on" or "on" in the direction opposite to gravity.

[0031] Furthermore, throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0032] Additionally, throughout the specification, "planar" means when the subject part is viewed from above, and "cross-sectional" means when the cross-section obtained by vertically cutting the subject part is viewed from the side.

[0033] In this specification, the phrase “(the intermediate layer) comprises a compound represented by Chemical Formula 1” may be interpreted as “(the intermediate layer) may comprise one compound belonging to the category of Chemical Formula 1 or two or more different compounds belonging to the category of Chemical Formula 1.”

[0034] In this specification, "Group" refers to a group on the IUPAC periodic table of elements.

[0035] In this specification, "alkali metal" means a Group 1 element. Specifically, the alkali metal may be lithium (Li), sodium (Na), potassium (K), rubidium (Rb), or cesium (Cs).

[0036] In this specification, "alkaline earth metal" means a Group 2 element. Specifically, the alkaline earth metal may be magnesium (Mg), calcium (Ca), strontium (Sr), or barium (Ba).

[0037] In this specification, "lanthanum metal" means lanthanum and lanthanide elements on the periodic table. Specifically, lanthanide metals may be lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), or ruthenium (Ru).

[0038] In this specification, "transition metal" means an element belonging to periods 4 through 7 and to groups 3 through 12. Specifically, the transition metal may be titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), or cadmium (Cd).

[0039] In this specification, "post-transition metal" refers to a metallic element belonging to periods 4 through 7 and to groups 13 through 17. Specifically, the post-transition metal may be aluminum (Al), gallium (Ga), indium (In), thallium (Tl), tin (Sn), lead (Pb), bismuth (Bi), or polonium (Po).

[0040] In this specification, "halogen" means a Group 17 element. Specifically, the halogen may be fluorine (F), chlorine (Cl), bromine (Br), or iodine (I).

[0041] In this specification, "inorganic semiconductor compound" means any compound that is inorganic and has a band gap of less than 4 eV. Specifically, the inorganic semiconductor compound may include halides of lanthanide metals, halides of transition metals, halides of post-transition metals, tellurium, tellurides of lanthanide metals, tellurides of transition metals, tellurides of post-transition metals, selenides of lanthanide metals, selenides of transition metals, selenides of post-transition metals, or any combination thereof. More specifically, the inorganic semiconductor compound may include EuI2, YbI2, SmI2, TmI2, AgI, CuI, NiI2, CoI2, BiI3, PbI2, SnI2, Te, EuTe, YbTe, SmTe, TmTe, EuSe, YbSe, SmSe, TmSe, ZnTe, CoTe, ZnSe, CoSe, Bi2Te3, Bi2Se3, or any combination thereof.

[0042] In this specification, "inorganic insulating compound" means any compound that is inorganic and has a band gap of 4 eV or more. Specifically, inorganic insulating compounds may include halides of alkali metals, halides of alkaline earth metals, halides of lanthanide metals, or any combination thereof. More specifically, the inorganic insulating compound may include NaI, KI, RbI, CsI, NaCl, KCl, RbCl, CsCl, NaF, KF, RbF, CsF, MgI2, CaI2, SrI2, BaI2, MgCl2, CaCl2, SrCl2, BaCl2, MgF2, CaF2, SrF2, BaF2, EuI3, YbI3, SmI3, TmI3, EuCl3, YbCl3, SmCl3, TmCl3, EuF3, YbF3, SmF3, TmF3, or any combination thereof.

[0043] In this specification, "halides of alkali metals" means compounds in which an alkali metal and a halogen are ionically bonded. Specifically, halides of alkali metals may include NaI, KI, RbI, CsI, NaCl, KCl, RbCl, CsCl, NaF, KF, RbF, CsF, or any combination thereof.

[0044] In this specification, "halogenates of alkaline earth metals" refers to compounds in which an alkaline earth metal and a halogen are ionically bonded. Specifically, halogenates of alkaline earth metals may include MgI2, CaI2, SrI2, BaI2, MgCl2, CaCl2, SrCl2, BaCl2, MgF2, CaF2, SrF2, BaF2, or any combination thereof.

[0045] In this specification, "halides of lanthanide metals" means compounds in which a lanthanide metal and a halogen are ionically and / or covalently bonded. Specifically, halides of lanthanide metals may include EuI2, YbI2, SmI2, TmI2, EuI3, YbI3, SmI3, TmI3, EuCl3, YbCl3, SmCl3, TmCl3, EuF3, YbF3, SmF3, TmF3, or any combination thereof.

[0046] In this specification, "halides of transition metals" means compounds in which a transition metal and a halogen are ionicly and / or covalently bonded. Specifically, halides of transition metals may include AgI, CuI, NiI2, CoI2, or any combination thereof.

[0047] In this specification, "halides of post-transition metals" means compounds in which a post-transition metal and a halogen are ionicly and / or covalently bonded. Specifically, halides of post-transition metals may include BiI3, PbI2, SnI2, or any combination thereof.

[0048] In this specification, "tellurides of lanthanide metals" means compounds in which a lanthanide metal and tellurium (Te) are ionically, covalently, and / or metallically bonded. Specifically, tellurides of lanthanide metals may include EuTe, YbTe, SmTe, TmTe, or any combination thereof.

[0049] In this specification, "tellurides of transition metals" means compounds in which a transition metal and tellurium are ionicly, covalently, and / or metallically bonded. Specifically, tellurides of transition metals may include ZnTe, CoTe, or any combination thereof.

[0050] In this specification, "tellurides of post-transition metals" refers to compounds in which a post-transition metal and tellurium are ionicly, covalently, and / or metallically bonded. Specifically, tellurides of post-transition metals may include Bi2Te3.

[0051] In this specification, "selenides of lanthanide metals" means compounds in which a lanthanide metal and selenium (Se) are ionically, covalently, and / or metallically bonded. Specifically, selenides of lanthanide metals may include EuSe, YbSe, SmSe, TmSe, or any combination thereof.

[0052] In this specification, "selenide of a transition metal" means a compound in which a transition metal and selenium are ionicly, covalently, and / or metallically bonded. Specifically, a selenide of a transition metal may include ZnSe, CoSe, or any combination thereof.

[0053] In this specification, "selenide of a post-transition metal" refers to a compound in which a post-transition metal and selenium are ionicly, covalently, and / or metallically bonded. Specifically, a selenide of a post-transition metal may include Bi2Se3.

[0054] Hereinafter, a light-emitting element according to one embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a schematic cross-sectional view of a light-emitting element according to one embodiment, and FIGS. 2 and FIGS. 3 are cross-sectional views of a second electrode according to one embodiment.

[0055] First, referring to FIG. 1, the light-emitting element (1) may include a first electrode (E1), a second electrode (E2), and a light-emitting unit (EL) located between the first electrode (E1) and the second electrode (E2).

[0056] A light-emitting element (1) according to one embodiment of the present invention may be a front-emitting type. In this case, the first electrode (E1) may be an anode and the second electrode (E2) may be a cathode. A light-emitting element (1) according to another embodiment of the present invention may be a back-emitting type. In this case, the first electrode (E1) may be a cathode and the second electrode (E2) may be an anode. In the light-emitting element (1) according to one embodiment of the present invention, since the first electrode (E1) is a reflective electrode and the second electrode (E2) is a transmissive or semi-transmissive electrode, the light-emitting element (1) can emit light from the first electrode (E1) toward the second electrode (E2). Below, the case where the light-emitting element is a front-emitting type will be described.

[0057] The first electrode (E1) can be formed, for example, by providing a material for the first electrode on a substrate using a deposition method or a sputtering method. When the first electrode (E1) is an anode, the material for the first electrode can be selected from materials having a high work function so that hole injection is easy.

[0058] The first electrode (E1) may be a reflective electrode, a semi-transparent electrode, or a transparent electrode. To form the first electrode (E1) which is a transparent electrode, the material for the first electrode may be selected from indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO2), zinc oxide (ZnO), and any combination thereof, but is not limited thereto. Alternatively, to form the first electrode (E1) which is a semi-transparent electrode or a reflective electrode, the material for the first electrode may be selected from magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), and any combination thereof, but is not limited thereto.

[0059] The first electrode (E1) may have a single-layer structure or a multilayer structure having multiple layers. For example, the first electrode (E1) may have a three-layer structure of ITO / Ag / ITO, but is not limited thereto.

[0060] A light-emitting unit (EL) is disposed on the upper part of the first electrode (E1). Although the present specification illustrates an embodiment including one light-emitting unit (EL), it is not limited thereto, and a light-emitting element (1) according to one embodiment may include at least one light-emitting unit (EL).

[0061] The light-emitting unit (EL) may include an emitting layer (EML). Additionally, the light-emitting unit (EL) may include at least one of a hole transport region (HTR) and an electron transport region (ETR). The hole transport region (HTR) may include a hole injection layer, a hole transport layer, an electron blocking layer, or any combination thereof. The electron transport region (ETR) may include a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

[0062] A hole transport region (HTR) can be formed using general methods known in the art. For example, a hole transport region (HTR) can be formed using various methods such as vacuum deposition, spin coating, casting, the Langmuir-Blodgett (LB) method, inkjet printing, laser printing, and laser-induced thermal imaging (LITI).

[0063] The hole injection layer included in the hole transport region (HTR) may include a hole injection material. The hole injection material is a phthalocyanine compound 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 / Camphor sulfonicacid), PANI / PSS (Polyaniline / Poly(4-styrenesulfonate)), It may include NPB (N,N'-di(naphthalene-l-yl)-N,N'-diphenyl-benzidine), NPD (N,N'-Di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine), polyetherketone containing triphenylamine (TPAPEK), 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.

[0064] The hole transport layer included in the hole transport region may include a hole transport material. Hole transport substances include carbazole derivatives such as N-phenylcarbazole and polyvinylcarbazole, fluorene derivatives, triphenylamine derivatives such as TPD (N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1-biphenyl]-4,4'-diamine) and TCTA (4,4',4"-tris(N-carbazolyl)triphenylamine), NPB (N,N'-di(naphthalene-l-yl)-N,N'-diphenyl-benzidine), TAPC (4,4'-Cyclohexylidene bis[N,N-bis(4-methylphenyl)benzenamine]), HMTPD (4,4'-Bis[N,N'-(3-tolyl)amino]-3,3'-dimethylbiphenyl), and mCP (1,3-Bis(N-carbazolyl)benzene), It may include CzSi (9-(4-tert-Butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole), m-MTDATA (4,4',4"-[tris(3-methylphenyl)phenylamino] triphenylamine), etc.

[0065] The thickness of the hole transport region (HTR) may be about 100 Å to about 10,000 Å, for example, about 100 Å to about 5,000 Å. The thickness of the hole injection layer may be, for example, about 30 Å to about 1,000 Å, and the thickness of the hole transport layer may be about 30 Å to about 1,000 Å. When the thicknesses of the hole transport region (HTR), the hole injection layer, and the hole transport layer satisfy the ranges described above, satisfactory hole transport characteristics can be obtained without a substantial increase in driving voltage.

[0066] The electron blocking layer is a layer that prevents electrons from leaking from the electron transport region (ETR) to the hole transport region (HTR). The thickness of the electron blocking layer can be about 10 Å to about 1000 Å. The electron blocking layer may include, for example, carbazole derivatives such as N-phenylcarbazole and 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(naphthalene-l-yl)-N,N'-diplienyl-benzidine), TAPC (4,4'-Cyclohexylidene bis[N,N-bis(4-methylphenyl)benzenamine]), HMTPD (4,4'-Bis[N,N'-(3-tolyl)amino]-3,3'-dimethylbiphenyl), or mCP.

[0067] In addition to the aforementioned materials, the hole transport region (HTR) may further include a charge-generating material to enhance conductivity. The charge-generating material may be uniformly or non-uniformly dispersed within the hole transport region (HTR). The charge-generating material may be, for example, a p-dopant. The p-dopant may be one of quinone derivatives, metal oxides, and cyano group-containing compounds, but is not limited thereto. For example, non-limiting examples of p-dopants include quinone derivatives such as TCNQ (Tetracyanoquinodimethane) and F4-TCNQ (2,3,5,6-tetrafluoro-7,7', 8, 8'-tetracyanoquinodimethane), metal oxides such as tungsten oxide and molybdenum oxide, but are not limited thereto.

[0068] Each layer of the electron transport region (ETR) can be formed using general methods known in the art. For example, the electron transport region (ETR) can be formed using various methods such as vacuum deposition, spin coating, casting, the Langmuir-Blodgett (LB) method, inkjet printing, laser printing, and laser-induced thermal imaging (LITI).

[0069] The electron injection layer included in the electron transport region (ETR) may include an electron injection material. The electron injection material may be a metal halide such as LiF, NaCl, CsF, RbCl, RbI, a lanthanide metal such as Yb, a metal oxide such as Li2O, BaO, or LiQ (Lithium quinolate), but is not limited thereto. The electron injection layer may also be composed of a material in which the electron transport material and an insulating organometal salt are mixed. The organometal salt may be a material having an energy band gap of approximately 4 eV or more. Specifically, for example, the organometal salt may include metal acetate, metal benzoate, metal acetoacetate, metal acetylacetonate, or metal stearate.

[0070] The electron transport layer comprising the electron transport region (ETR) may include an electron transport material. The electron transport material may include a triazine compound or an anthracene compound. However, it is not limited thereto, and electron transport materials include, for example, Alq3(Tris(8-hydroxyquinolinato)aluminum), 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzoimidazolyl-1-ylphenyl)-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-quinolinolato-N1,O8)-(1,1'-Biphenyl-4-olato)aluminum), Bebq2(berylliumbis(benzoquinolin-10-olate), ADN(9,10-di(naphthalene-2-yl)anthracene), TSPO1(diphenyl(4-(triphenylsilyl)phenyl)phosphine oxide), TPM-TAZ It may include (2,4,6-Tris(3-(pyrimidin-5-yl)phenyl)-1,3,5-triazine) and mixtures thereof.

[0071] The thickness of each electron injection layer can be about 1 Å to about 500 Å or about 3 Å to about 300 Å. When the thickness of the electron injection layer satisfies the range described above, satisfactory electron injection characteristics can be obtained without a substantial increase in driving voltage.

[0072] The thickness of each electron transport layer can be about 100 Å to about 1000 Å, for example, about 150 Å to about 500 Å. When the thickness of the electron transport layer satisfies the range described above, satisfactory electron transport characteristics can be obtained without a substantial increase in driving voltage.

[0073] The hole blocking layer is a layer that prevents holes from leaking from the hole transport region (HTR) to the electron transport region (ETR). The thickness of the hole blocking layer may be about 10 Å to about 1000 Å. The hole blocking layer may include, for example, at least one of BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), Bphen (4,7-diphenyl-1,10-phenanthroline), and T2T (2,4,6-tri([1,1'-biphenyl]-3-yl)-1,3,5-triazine), but is not limited thereto.

[0074] The light-emitting layer (EML) may include one or more selected from organic compounds and semiconductor compounds, but is not limited thereto. When the light-emitting layer (EML) includes an organic compound, the light-emitting device may be referred to as an organic light-emitting device.

[0075] The above organic compound may include a host and a dopant. The above semiconductor compound may be a quantum dot, that is, the above light-emitting device may be a quantum dot light-emitting device. Alternatively, the above semiconductor compound may be an organic and / or inorganic perovskite.

[0076] The thickness of the light-emitting layer (EML) may be about 0.1 nm to about 100 nm. Specifically, the thickness of the light-emitting layer (EML) may be 15 nm to 50 nm. More specifically, when the light-emitting layer (EML) emits blue light, the thickness of the blue light-emitting layer may be 15 nm to 20 nm; when the light-emitting layer emits green light, the thickness of the green light-emitting layer may be 20 nm to 40 nm; and when the light-emitting layer emits red light, the thickness of the red light-emitting layer may be 40 nm to 50 nm. When satisfying the above ranges, the light-emitting device can exhibit excellent light-emitting characteristics without a substantial increase in driving voltage.

[0077] The emitting layer (EML) may include a host material and a dopant material. The emitting layer (EML) may be formed by using a phosphorescent or fluorescent emitting material as a dopant in the host material. The emitting layer (EML) may be formed by including a thermally activated delayed fluorescence (TADF) dopant in the host material. Alternatively, the emitting layer (EML) may include a quantum dot material as the emitting material. 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 combinations thereof.

[0078] The color of light emitted from the emissive layer (EML) can be determined by the combination of the host material and the dopant material, or by the type of quantum dot material and the size of the core, etc.

[0079] As a host material for the light-emitting layer (EML), known materials may be used, and are not particularly limited, but are selected from fluoranthene derivatives, pyrene derivatives, arylacetylene derivatives, anthracene derivatives, fluorene derivatives, perylene derivatives, chrysene derivatives, etc. Preferably, pyrene derivatives, perylene derivatives, and anthracene derivatives may be used.

[0080] As a dopant material for the emissive layer (EML), known materials may be used and are not particularly limited, but styryl derivatives (e.g., 1,4-bis[2-(3-N-ethylcarbazoryl)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-phenylbenzenamine (N-BDAVBi), perylene and its derivatives (e.g., 2,5,8,11-Tetra-t-butylperylene (TBP)), pyrene and its derivatives (e.g., 1,1-dipyrene, 1,4-dipyrenylbenzene, 1,4-Bis(N, It may include N-Diphenylamino)pyrene), N1,N6-di(naphthalen-2-yl)-N1,N6-diphenylpyrene-1,6-diamine), etc.

[0081] The thickness of the second electrode (E2) may be 5 nm to 20 nm. When the above range is satisfied, light absorption at the second electrode can be minimized, and satisfactory electron injection characteristics can be obtained without a substantial increase in driving voltage.

[0082] The second electrode (E2) may have a multilayer structure having a plurality of layers. Referring to FIGS. 2 and 3 below, the specific structure of the second electrode (E2) according to one embodiment will be examined.

[0083] Referring to FIGS. 2 and 3, a second electrode (E2) according to one embodiment may include a first layer (E2-a) and a metal thin film layer (E2-b). The first layer (E2-a) may be located adjacent to a light-emitting unit (EL), and the metal thin film layer (E2-b) may be located on top of the first layer (E2-a). Although the present specification illustrates and describes an embodiment in which the second electrode (E2) includes the first layer (E2-a), it is not limited thereto, and an embodiment in which a layer corresponding to the characteristics and material of the first layer (E2-a) is included in the light-emitting unit (EL), particularly the electron transport region (ETR), or is located between the light-emitting unit (EL) and the second electrode (E2) may also be possible.

[0084] The first layer (E2-a) may include a first organic material. The first organic material may be capable of forming a coordination bond with the metal included in the metal thin film layer (E2-b) to be described later. The first organic material according to one embodiment may include any material capable of forming a coordination bond with the metal of the metal thin film layer (E2-b), but as an example, it may include a phenanthroline group, a pyrene group, a furan group, or a thiol group.

[0085] Additionally, the first layer (E2-a) according to the embodiment may further include a first metal. The first metal may further include at least one of Yb, Li, Cu, Ag, Au, Al, and Mg.

[0086] According to one embodiment, the thickness of the first layer (E2-a) may be about 10 Angstroms to about 100 Angstroms. If the thickness of the first layer (E2-a) exceeds about 100 Angstroms, the thickness of the second electrode (E2) may become excessively thick, and if the thickness of the first layer (E2-a) is less than about 10 Angstroms, it may not be easy to form a metal thin film layer (E2-b) on the first layer (E2-a).

[0087] The metal thin film layer (E2-b) may contain one type of metal. For example, the metal thin film layer (E2-b) is 1 x 10 7 It may include a metal having an electrical conductivity of S / m or greater. As an example, the metal thin film layer (E2-b) may include any one of Ag, Au, Cu, Al, and Mg.

[0088] A first layer (E2-a) according to one embodiment may include an organic compound comprising a coordination bonding site (A) as shown in Chemical Formula 1 below.

[0089] [Chemical Formula 1]

[0090] In the above Chemical Formula 1, R1, R2, R3, R3, R5, and R6 are each independently hydrogen, deuterium, halogen, amine group, epoxy group, cyclohexyl epoxy group, acrylic group, methacrylic group, thiol group, isocyanate group, nitrile group, nitro group, substituted or unsubstituted C1-C 60 Alkyl groups, substituted or unsubstituted C2-C 60 alkenyl groups, substituted or unsubstituted C1-C 60 Alkoxy groups, substituted or unsubstituted C3-C 10 Cycloalkyl groups, substituted or unsubstituted C1-C 10 Heterocycloalkyl groups, substituted or unsubstituted C6-C 60 Aryl groups, substituted or unsubstituted C1-C 60 Heteroaryl group, substituted or unsubstituted C7-C 12 Aralkyl groups, substituted or unsubstituted C6-C 60aryloxy groups, or substituted or unsubstituted C6-C 60 It may be selected from arylthio groups, but is not limited thereto. For example, the above chemical formula 1 may be represented by the following chemical formula 1-1, but is not limited thereto.

[0091] [Chemical Formula 1-1]

[0092] As illustrated in FIG. 3, a coordination bond can be formed between the metal (M) contained in the metal thin film layer (E2-b) and the coordination bond site (A) contained in the first layer (E2-a). When forming the metal thin film layer (E2-b) on the first layer (E2-a), the coordination bond site (A) of the first layer (E2-a) can induce bonding with the metal atoms (M) of the metal thin film layer (E2-b). Accordingly, it is possible to form a metal thin film layer (E2-b) having a stable film quality and a thin thickness on the first layer (E2-a). That is, the metal thin film layer (E2-b) can be formed as a uniform film quality containing a single metal, and at this time, it can have characteristics of high transmittance and conductivity.

[0093] Hereinafter, a light-emitting element according to one embodiment will be described with reference to FIGS. 4 to 6. FIGS. 4, FIGS. 5, and FIGS. 6 are each cross-sectional views of a second electrode according to one embodiment. Descriptions of components identical to the aforementioned components may be omitted.

[0094] Referring to FIGS. 4 and 5, a second electrode (E2) according to one embodiment may include a first layer (E2-a), a metal thin film layer (E2-b), and a holding layer (E2-c). The first layer (E2-a) may be located adjacent to a light-emitting unit (EL), and a metal thin film layer (E2-b) may be located on the first layer (E2-a). A holding layer (E2-c) may be located on the metal thin film layer (E2-b). The metal thin film layer (E2-b) may be located between the holding layer (E2-c) and the first layer (E2-a).

[0095] The present specification illustrates and describes an embodiment in which the second electrode (E2) comprises a first layer (E2-a), a metal thin film layer (E2-b), and a holding layer (E2-c), but is not limited thereto. An embodiment may also be possible in which the first layer (E2-a) is included in a light-emitting unit (EL), particularly an electron transport region (ETR), and the holding layer (E2-c) is included in an encapsulation layer located on the light-emitting element.

[0096] The first layer (E2-a) and the holding layer (E2-c) may independently include organic materials. The first layer (E2-a) may include a first organic material, and the holding layer (E2-c) may include a second organic material. Each of the first organic material and the second organic material may be capable of forming a coordination bond with the metal included in the metal thin film layer (E2-b) to be described later. Each of the first organic material and the second organic material according to one embodiment may include any material capable of forming a coordination bond with the metal included in the metal thin film layer (E2-b), and as an example, they may independently include a phenanthroline group, a pyrene group, a furan group, or a thiol group.

[0097] The first layer (E2-a) may further include a first metal doped into the first organic material. Additionally, the holding layer (E2-c) may further include a second metal doped into the second organic material. Each of the first metal and the second metal may independently further include at least one of Yb, Li, Cu, Ag, Au, Al, and Mg.

[0098] According to one embodiment, the thickness of the first layer (E2-a) may be about 10 Angstroms to about 100 Angstroms. If the thickness of the first layer (E2-a) exceeds about 100 Angstroms, the thickness of the second electrode (E2) may become excessively thick, and if the thickness of the first layer (E2-a) is less than about 10 Angstroms, it may not be easy to form a metal thin film layer (E2-b) on the first layer (E2-a).

[0099] According to one embodiment, the thickness of the holding layer (E2-c) may be about 10 Angstroms to about 700 Angstroms. According to one embodiment, the holding layer (E2-c) may have a thickness of about 10 Angstroms to about 50 Angstroms or a thickness of about 400 Angstroms to about 700 Angstroms. When the thickness of the holding layer (E2-c) is about 10 Angstroms to about 50 Angstroms, the display device according to one embodiment may further include an auxiliary holding layer located on the holding layer (E2-c).

[0100] The above auxiliary holding layer may include, for example, α-NPD, NPB, TPD, m-MTDATA, Alq3, CuPc, TPD15 (N4,N4,N4',N4'-tetra (biphenyl-4-yl)biphenyl-4,4'-diamine), TCTA (4,4',4"-tris(N-carbazolyl)triphenylamine), N, N'-bis (naphthalen-1-yl), etc. The auxiliary holding layer serves to help light emitted from the light-emitting layer (EML) of the light-emitting element to efficiently exit the light-emitting element. If the light-emitting element of one embodiment further includes a thin film encapsulation layer, the auxiliary holding layer may be disposed between the second electrode (E2) and the thin film encapsulation layer.

[0101] The metal thin film layer (E2-b) may include at least one type of metal. As an example, the metal thin film layer (E2-b) is 1 x 10 7It may include a metal having an electrical conductivity of S / m or greater. As an example, the metal thin film layer (E2-b) may include any one of Ag, Au, Cu, Al, and Mg.

[0102] According to one embodiment, the first layer (E2-a) and the holding layer (E2-c) may include a first organic material and a second organic material comprising a coordination bonding site (A) as shown in Chemical Formula 1 below.

[0103] [Chemical Formula 1]

[0104] The coordination bonding site (A) containing the first organic material and the second organic material can form a coordination bond with the metal (M) contained in the metal thin film layer (E2-b) as shown in FIG. 5. In forming the metal thin film layer (E2-b), the first organic material of the first layer (E2-a) and the second organic material of the holding layer (E2-c) can induce bonding with the metal (M) of the metal thin film layer (E2-b). Accordingly, the metal thin film layer (E2-b) can be formed on the first layer (E2-a) to have a stable film quality and a thin thickness. The metal thin film layer (E2-b) can be formed as a uniform film containing a single metal, and in this case, it can have characteristics of high transmittance and conductivity.

[0105] Referring to FIG. 6, a second electrode (E2) according to one embodiment may further include an auxiliary layer (E2-d) located below the first layer (E2-a). The auxiliary layer (E2-d) may have a higher electron affinity compared to the first layer (E2-a). The LUMO energy level of the auxiliary layer (E2-d) according to one embodiment may be smaller than the LUMO energy level of the first layer (E2-a). The auxiliary layer (E2-d) may include any organic or inorganic material that satisfies these conditions, such as HAT-CN, MoO3, etc.

[0106]

[0107] Hereinafter, a light-emitting element according to one embodiment will be described with reference to FIG. 7. FIG. 7 is a schematic cross-sectional view of a light-emitting element according to one embodiment. Descriptions of components identical to those described above will be omitted.

[0108] Referring to FIG. 7, the light-emitting element (1) may include m light-emitting units (EL). The light-emitting element (1) according to one embodiment may include m-1 charge-generating layers (CGL1, CGL2, CGL3) interposed between adjacent light-emitting units (EL). The light-emitting element (1) according to one embodiment may include a first charge-generating layer (CGL1) located between a first light-emitting unit (EL1) and a second light-emitting unit (EL2), a second charge-generating layer (CGL2) located between a second light-emitting unit (EL2) and a third light-emitting unit (EL3), and a third charge-generating layer (CGL3) located between a third light-emitting unit (EL3) and a fourth light-emitting unit (EL4). Although the present specification illustrates an embodiment including three charge-generating layers (CGL1, CGL2, CGL3), it is not limited thereto and may vary depending on the number of light-emitting units (EL).

[0109] Each charge generation layer (CGL1, CGL2, CGL3) may include an n-type charge generation layer (n-CGL1, n-CGL2, n-CGL3) that provides electrons to the light-emitting unit (EL) and a p-type charge generation layer (p-CGL1, p-CGL2, p-CGL3) that provides holes to the light-emitting unit (EL). Although not illustrated, a buffer layer may be further disposed between the n-type charge generation layer (n-CGL1, n-CGL2, n-CGL3) and the p-type charge generation layer (p-CGL1, p-CGL2, p-CGL3) according to the embodiment.

[0110] The charge generation layers (CGL1, CGL2, CGL3) can generate charges (electrons and holes) by forming a complex through an oxidation-reduction reaction when voltage is applied. The charge generation layers (CGL1, CGL2, CGL3) can supply the generated charges to adjacent light-emitting units (EL). The charge generation layers (CGL1, CGL2, CGL3) can double the current efficiency generated in the light-emitting units (EL) and can play a role in regulating the balance of charges between adjacent light-emitting units (EL).

[0111] 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). The first n-type charge generation layer (n-CGL1) may be located adjacent to the first light-emitting unit (EL1), and the first p-type charge generation layer (p-CGL1) may be located adjacent to the second light-emitting unit (EL2). 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). The second n-type charge generation layer (n-CGL2) may be located adjacent to the second light-emitting unit (EL2), and the second p-type charge generation layer (p-CGL2) may be located adjacent to the third light-emitting unit (EL3). 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). The third n-type charge generation layer (n-CGL3) may be located adjacent to the third light-emitting unit (EL3), and the third p-type charge generation layer (p-CGL3) may be located adjacent to the fourth light-emitting unit (EL4).

[0112] A second electrode (E2) is disposed on the m-th light-emitting unit (EL). The second electrode (E2) may be a cathode, which is an electron injection electrode. The second electrode (E2) may be the second electrode (E2) described above in FIGS. 1 to 3, the second electrode (E2) described in FIGS. 4 to 5, or the second electrode (E2) described in FIG. 6.

[0113] A display device according to one embodiment will be examined below with reference to FIGS. 8 to 10. FIG. 8 is an exploded perspective view of a display device according to one embodiment, FIG. 9 is a schematic cross-sectional view of a display panel according to one embodiment, and FIG. 10 is a cross-sectional view of a display panel according to one embodiment.

[0114] Referring to FIG. 8, a display device according to one embodiment may include a cover window (CW), a display panel (DP), and a housing (HM).

[0115] The cover window (CW) may include an insulating panel. For example, the cover window (CW) may be made of glass, plastic, or a combination thereof.

[0116] The front of the cover window (CW) may define the front of the display device (1000). The transmission area (TA) may be an optically transparent area. For example, the transmission area (TA) may be an area with a visible light transmittance of about 90% or more.

[0117] The blocking region (CBA) can define the shape of the transmitting region (TA). The blocking region (CBA) is adjacent to the transmitting region (TA) and can surround the transmitting region (TA). The blocking region (CBA) may be an area with a relatively lower light transmittance compared to the transmitting region (TA). The blocking region (BA) may include an opaque material that blocks light. The blocking region (BA) may have a predetermined color. The blocking region (CBA) may be defined by a bezel layer provided separately from the transparent substrate defining the transmitting region (TA), or by an ink layer formed by being inserted into or colored in the transparent substrate.

[0118] One side of the display panel (DP) on which an image is displayed is parallel to the surface defined by the first direction (DR1) and the second direction (DR2). The normal direction of the one side on which the image is displayed, that is, the thickness direction of the display panel (DP), is indicated by the third direction (DR3). The front (or top) and back (or bottom) sides of each member are distinguished by the third direction (DR3). However, the directions indicated by the first to third directions (DR1, DR2, DR3) can be converted to other directions as a relative concept.

[0119] The display panel (DP) may be a flat rigid display panel, but is not limited thereto and may be a flexible display panel. Meanwhile, the display panel (DP) may be an organic light-emitting display panel. However, the type of the display panel (DP) is not limited thereto and may be composed of various types of panels. For example, the display panel (DP) may be a liquid crystal display panel, an electrophoretic display panel, an electrowetting display panel, etc. In addition, the display panel (DP) may be a next-generation display panel such as a micro light-emitting diode display panel, a quantum dot light-emitting diode display panel, or a quantum dot organic light-emitting diode display panel.

[0120] Micro LED display panels are constructed such that each pixel is composed of light-emitting diodes with a size of 10 to 100 micrometers. Such Micro LED display panels have advantages such as using inorganic materials, the ability to omit a backlight, fast response speed, the ability to achieve high brightness with low power, and not breaking when bent. Quantum dot light-emitting diode display panels are constructed by attaching a film containing quantum dots or by forming a material containing quantum dots. Quantum dots refer to particles composed of inorganic materials such as indium and cadmium that emit light on their own and have a diameter of several nanometers or less. By controlling the particle size of the quantum dots, light of a desired color can be displayed. Quantum dot organic light-emitting diode display panels are constructed by using a blue organic light-emitting diode as a light source and implementing color by attaching a film containing red and green quantum dots or by depositing a material containing red and green quantum dots on top of it. The display panel (DP) according to one embodiment may also be composed of various other display panels.

[0121] As illustrated in FIG. 8, the display panel (DP) includes a display area (DA) where an image is displayed, and a non-display area (PA) adjacent to the display area (DA). The non-display area (PA) is an area where no image is displayed. The display area (DA) may be rectangular in shape, for example, and the non-display area (PA) may have a shape that surrounds the display area (DA). However, it is not limited thereto, and the shapes of the display area (DA) and the non-display area (PA) may be designed relative to each other.

[0122] The housing (HM) provides a predetermined internal space. A display panel (DP) is mounted inside the housing (HM). In addition to the display panel (DP), various electronic components, such as a power supply, a storage device, and an audio input / output module, may be mounted inside the housing (HM).

[0123] Next, with reference to FIG. 9, a display panel according to one embodiment is examined. Referring to FIG. 8 and FIG. 9, a plurality of pixels (PA1, PA2, PA3) may be formed on a substrate (SUB) corresponding to a display area (DA) of a display panel (DP). Each pixel (PA1, PA2, PA3) may include a plurality of transistors and light-emitting elements connected thereto.

[0124] An encapsulation layer (ENC) may be located on multiple pixels (PA1, PA2, PA3). The display area (DA) may be protected from the outside air or moisture through the encapsulation layer (ENC). The encapsulation layer (ENC) may be integrally provided to overlap the front surface of the display area (DA), and may also be partially disposed on the non-display area (PA).

[0125] A first color conversion unit (CC1), a second color conversion unit (CC2), and a transmission unit (CC3) may be located on the encapsulation layer (ENC). The first color conversion unit (CC1) may overlap with the first pixel (PA1), the second color conversion unit (CC2) may overlap with the second pixel (PA2), and the transmission unit (CC3) may overlap with the third pixel (PA3).

[0126] The light emitted from the first pixel (PA1) can pass through the first color conversion unit (CC1) to provide red light (LR). The light emitted from the second pixel (PA2) can pass through the second color conversion unit (CC2) to provide green light (LG). The light emitted from the third pixel (PA3) can pass through the transmission unit (CC3) to provide blue light (LB).

[0129] Below, we examine the stacking structure of each pixel (PA1, PA2, PA3) and the stacking structure of the color conversion unit (CC1, CC2) and the transmission unit (CC3).

[0130] Referring to FIG. 10, a color conversion unit (CC) may be located on a pixel unit (PP) including first to third pixels (PA1, PA2, PA3).

[0131] Referring to FIG. 10, a pixel portion (PP) according to one embodiment includes a substrate (SUB). The substrate (SUB) may include an inorganic insulating material such as glass or an organic insulating material such as plastic such as polyimide (PI). The substrate (SUB) may be a single layer or a multilayer. The substrate (SUB) may have a structure in which at least one base layer comprising a sequentially stacked polymer resin and at least one inorganic layer are alternately stacked.

[0132] The substrate (SUB) can have varying degrees of flexibility. The substrate (SUB) can be a rigid substrate or a flexible substrate capable of bending, folding, rolling, etc.

[0133] A buffer layer (BF) may be located on the substrate (SUB). The buffer layer (BF) can prevent the transfer of impurities from the substrate (SUB) to the upper layer of the buffer layer (BF), particularly the semiconductor layer (ACT), thereby preventing the degradation of the semiconductor layer (ACT)'s characteristics and relieving stress. The buffer layer (BF) may include an inorganic insulating material, such as silicon nitride or silicon oxide, or an organic insulating material. Part or all of the buffer layer (BF) may be omitted.

[0134] A semiconductor layer (ACT) is located on a buffer layer (BF). The semiconductor layer (ACT) may include at least one of polycrystalline silicon and oxide semiconductor. The semiconductor layer (ACT) includes a channel region (C), a first region (P), and a second region (Q). The first region (P) and the second region (Q) are each positioned on opposite sides of the channel region (C). The channel region (C) may include a semiconductor that is doped with a small amount of impurities or is not doped with impurities, and the first region (P) and the second region (Q) may include semiconductors that are doped with a large amount of impurities relative to the channel region (C). The semiconductor layer (ACT) may be made of an oxide semiconductor, in which case a separate protective layer (not shown) may be added to protect the oxide semiconductor material, which is vulnerable to external environments such as high temperatures.

[0135] A first gate insulating layer (GI1) is located on the semiconductor layer (ACT).

[0136] A gate electrode (GE) and a bottom electrode (LE) are located on the first gate insulating layer (GI1). According to an embodiment, the gate electrode (GE) and the bottom electrode (LE) may be formed integrally. The gate electrode (GE) and the bottom electrode (LE) may be a single layer or a multilayer film in which a metal film comprising any one of copper (Cu), copper alloy, aluminum (Al), aluminum alloy, molybdenum (Mo), molybdenum alloy, titanium (Ti), and titanium alloy is stacked. The gate electrode (GE) may overlap with the channel region (C) of the semiconductor layer (ACT).

[0137] A second gate insulating layer (GI2) may be located on the gate electrode (GE) and the first gate insulating layer (GI1). The first gate insulating layer (GI1) and the second gate insulating layer (GI2) are made of silicon oxide (SiO2). x ), silicon nitride (SiN x ) and silicon nitrate (SiO₂ x N y It may be a single layer or a multilayer including at least one of ).

[0138] An upper electrode (UE) may be located on the second gate insulating layer (GI2). The upper electrode (UE) may form a holding capacitor by overlapping with the lower electrode (LE).

[0139] A first interlayer insulating layer (IL1) is located on the upper electrode (UE). The first interlayer insulating layer (IL1) is silicon oxide (SiO₂). x ), silicon nitride (SiN x ) and silicon nitrate (SiO₂ x N y It may be a single layer or a multilayer including at least one of ).

[0140] A source electrode (SE) and a drain electrode (DE) are located on the first interlayer insulating layer (IL1). The source electrode (SE) and the drain electrode (DE) are electrically connected to the first region (P) and the second region (Q) of the semiconductor layer (ACT), respectively, through contact holes formed in the insulating layers.

[0141] The source electrode (SE) and drain electrode (DE) may include aluminum (Al), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni), chromium (Cr), nickel (Ni), calcium (Ca), molybdenum (Mo), titanium (Ti), tungsten (W), and / or copper (Cu), and may have a single-layer or multi-layer structure including the same.

[0142] A second interlayer insulating layer (IL2) is located on the first interlayer insulating layer (IL1), source electrode (SE), and drain electrode (DE). The second interlayer insulating layer (IL2) may include organic insulating materials such as general-purpose polymers like polymethylmethacrylate (PMMA) or polystyrene (PS), polymer derivatives having phenolic groups, acrylic polymers, imide polymers, polyimide, acrylic polymers, and siloxane polymers.

[0143] A first electrode (E1) may be located on the second interlayer insulating layer (IL2). The first electrode (E1) may be connected to a drain electrode (DE) through a contact hole in the second interlayer insulating layer (IL2).

[0144] The first electrode (E1) may include metals such as silver (Ag), lithium (Li), calcium (Ca), aluminum (Al), magnesium (Mg), and gold (Au), and may also include transparent conductive oxides (TCOs) such as indium tin oxide (ITO) and indium zinc oxide (IZO). The first electrode (E1) may be composed of a single layer containing a metal material or a transparent conductive oxide, or a multilayer containing these. For example, the first electrode (E1) may have a triple film structure of indium tin oxide (ITO) / silver (Ag) / indium tin oxide (ITO).

[0145] A transistor composed of a gate electrode (GE), a semiconductor layer (ACT), a source electrode (SE), and a drain electrode (DE) is connected to the first electrode (E1) to supply current to a light-emitting element.

[0146] A partition (IL3) is located above the second interlayer insulating layer (IL2) and the first electrode (E1). Although not shown, a spacer (not shown) may be located on the partition (IL3). The partition (IL3) has a partition opening that overlaps with at least a portion of the first electrode (E1) and defines a light-emitting region.

[0147] The partition wall (IL3) may include an organic insulating material such as a general-purpose polymer like polymethylmethacrylate (PMMA) or polystyrene (PS), a polymer derivative having a phenolic group, an acrylic polymer, an imide polymer, a polyimide, an acrylic polymer, or a siloxane polymer.

[0148] A light-emitting unit (EL) and a second electrode (E2) may be located on the partition (IL3). The second electrode may be the second electrode described above through FIGS. 1 to 3, the second electrode described through FIGS. 4 to 5, or the second electrode described through FIG. 6.

[0149] The first electrode (E1), the light-emitting unit (EL), and the second electrode (E2) can constitute a light-emitting element. Here, the first electrode (E1) may be an anode, which is a hole injection electrode, and the second electrode (E2) may be a cathode, which is an electron injection electrode. However, the embodiments are not necessarily limited thereto, and depending on the driving method of the light-emitting display device, the first electrode (E1) may be a cathode and the second electrode (E2) may be an anode.

[0150] An encapsulation layer (ENC) is positioned on the second electrode (E2). The encapsulation layer (ENC) can cover and seal not only the top surface of the light-emitting element but also its sides. Since the light-emitting element is highly susceptible to moisture and oxygen, the encapsulation layer (ENC) seals the light-emitting element to block the ingress of external moisture and oxygen.

[0151] The encapsulation layer (ENC) may include multiple layers, and may be formed as a composite membrane including both an inorganic layer and an organic layer, and as an example, may be formed as a triple layer in which a first encapsulation inorganic layer (EIL1), an encapsulation organic layer (EOL), and a second encapsulation inorganic layer (EIL2) are formed sequentially.

[0152] The first encapsulating inorganic layer (EIL1) can cover the second electrode (E2). The first encapsulating inorganic layer (EIL1) can prevent external moisture or oxygen from penetrating into the light-emitting element. For example, the first encapsulating inorganic layer (EIL1) may include silicon nitride, silicon oxide, silicon oxynitride, or a compound in combination thereof. The first encapsulating inorganic layer (EIL1) can be formed through a deposition process.

[0153] The encapsulating organic layer (EOL) is disposed on the first encapsulating inorganic layer (EIL1) and can come into contact with the first encapsulating inorganic layer (EIL1). Curvatures formed on the upper surface of the first encapsulating inorganic layer (EIL1) or particles present on the first encapsulating inorganic layer (EIL1) are covered by the encapsulating organic layer (EOL), thereby blocking the influence of the surface condition of the upper surface of the first encapsulating inorganic layer (EIL1) on the components formed on the encapsulating organic layer (EOL). Additionally, the encapsulating organic layer (EOL) can relieve stress between the contacting layers. The encapsulating organic layer (EOL) may contain organic material and can be formed through solution processes such as spin coating, slit coating, or inkjet processes.

[0154] The second encapsulating inorganic layer (EIL2) is placed on the encapsulating organic layer (EOL) to cover the encapsulating organic layer (EOL). The second encapsulating inorganic layer (EIL2) can be stably formed on a relatively flat surface compared to the one placed on the first encapsulating inorganic layer (EIL1). The second encapsulating inorganic layer (EIL2) encapsulates moisture, etc. released from the encapsulating organic layer (EOL) to prevent it from entering to the outside. The second encapsulating inorganic layer (EIL2) may include silicon nitride, silicon oxide, silicon oxynitride, or a compound formed by combining these. The second encapsulating inorganic layer (EIL2) can be formed through a deposition process.

[0155] A color conversion unit (CC) is located on the encapsulation layer (ENC).

[0156] The color conversion unit (CC) includes a first insulating layer (P1) located on the encapsulation layer (ENC). The first insulating layer (P1) may be integrally formed to overlap the entire display area. The first insulating layer (P1) is silicon oxide (SiO₂). x ), silicon nitride (SiN x ) and silicon nitrate (SiO₂ x N y It may be a single layer or a multilayer including at least one of ).

[0157] A first light-blocking layer (BM1) may be located on the first insulating layer (P1). The first light-blocking layer (BM1) may define an area where the first color-converting layer (CCL1), the second color-converting layer (CCL2), and the transparent layer (CCL3) are located.

[0158] A first color-converting layer (CCL1), a second color-converting layer (CCL2), and a transparent layer (CCL3) are located within the area defined by the first light-blocking layer (BM1). The first color-converting layer (CCL1), the second color-converting layer (CCL2), and the transparent layer (CCL3) may be formed by an inkjet process, but are not limited thereto and may be formed using any manufacturing method.

[0159] The transparent layer (CCL3) transmits light of a first wavelength incident from a light-emitting element and may include a plurality of scatterers (SC). At this time, the light of the first wavelength may be blue light having a maximum emission peak wavelength of about 380 nm to about 480 nm, for example, about 420 nm or more, about 430 nm or more, about 440 nm or more, or about 445 nm or more, and about 470 nm or less, about 460 nm or less, or about 455 nm or less.

[0160] The first color conversion layer (CCL1) converts light of a first wavelength incident from a light-emitting element into red light and may include a plurality of scatterers (SC) and a plurality of first quantum dots (SN1). At this time, the maximum emission peak wavelength of the red light may be about 600 nm to about 650 nm, for example, about 620 nm to about 650 nm.

[0161] The second color conversion layer (CCL2) converts light of a first wavelength incident from a light-emitting element into green light and may include a plurality of scatterers (SC) and a plurality of second quantum dots (SN2). The green light may have a maximum emission peak wavelength of about 500 nm to about 550 nm, for example, about 510 nm to about 550 nm.

[0162] Multiple scatterers (SC) can scatter light incident on the first color conversion layer (CCL1), the second color conversion layer (CCL2), and the transmission layer (CCL3) to increase light efficiency.

[0163] Each of the first quantum dot (SN1) and the second quantum dot (SN2) (hereinafter also referred to as semiconductor nanocrystals) may independently comprise a Group II-VI compound, a Group III-V compound, a Group IV-VI compound, a Group IV element or compound, a Group I-III-VI compound, a Group II-III-VI compound, a Group I-II-IV-VI compound, or a combination thereof. The quantum dots may not contain cadmium.

[0164] The above Group II-VI compounds are diatomic compounds selected from the group consisting of CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, and mixtures thereof; ternary compounds selected from the group consisting of AgInS, CuInS, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, and mixtures thereof; and may be selected from the group consisting of four-element compounds selected from the group consisting of HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, and mixtures thereof. The group II-VI compounds may further include a group III metal.

[0165] The above III-V group compounds may be selected from the group consisting of: diatomic compounds selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and mixtures thereof; ternary compounds selected from the group consisting of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InNP, InNAs, InNSb, InPAs, InZnP, InPSb, and mixtures thereof; and quaternary compounds selected from the group consisting of GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, InZnP, and mixtures thereof. The above III-V group compounds may further include a group II metal (e.g., InZnP).

[0166] The above IV-VI group compounds may be selected from the group consisting of diatomic compounds selected from SnS, SnSe, SnTe, PbS, PbSe, PbTe and mixtures thereof; ternary compounds selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe and mixtures thereof; and quaternary compounds selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe and mixtures thereof.

[0167] The above Group IV elements or compounds may be selected from the group consisting of monatomic compounds selected from the group consisting of Si, Ge, and combinations thereof; and diatomic compounds selected from the group consisting of SiC, SiGe, and combinations thereof, but are not limited thereto.

[0168] Examples of the above Group I-III-VI compounds include, but are not limited to, CuInSe2, CuInS2, CuInGaSe, and CuInGaS. Examples of the above Group I-II-IV-VI compounds include, but are not limited to, CuZnSnSe and CuZnSnS. The above Group IV element or compound may be selected from the group consisting of a monatomic element selected from the group consisting of Si, Ge, and mixtures thereof; and a diatomic compound selected from the group consisting of SiC, SiGe, and mixtures thereof.

[0169] The above Group II-III-VI compounds may be selected from the group consisting of ZnGaS, ZnAlS, ZnInS, ZnGaSe, ZnAlSe, ZnInSe, ZnGaTe, ZnAlTe, ZnInTe, ZnGaO, ZnAlO, ZnInO, HgGaS, HgAlS, HgInS, HgGaSe, HgAlSe, HgInSe, HgGaTe, HgAlTe, HgInTe, MgGaS, MgAlS, MgInS, MgGaSe, MgAlSe, MgInSe, and combinations thereof, but are not limited thereto.

[0170] The above Group I-II-IV-VI compounds may be selected from CuZnSnSe and CuZnSnS, but are not limited thereto.

[0171] In one embodiment, the quantum dot may not contain cadmium. The quantum dot may include semiconductor nanocrystals based on a Group III-V compound containing indium and phosphorus. The Group III-V compound may further include zinc. The quantum dot may include semiconductor nanocrystals based on a Group II-VI compound containing a chalcogen element (e.g., sulfur, selenium, tellurium, or a combination thereof) and zinc.

[0172] In quantum dots, the aforementioned binary compounds, ternary compounds, and / or quaternary compounds may exist within the particle at a uniform concentration, or may exist within the same particle with concentration distributions divided into partially different states. Additionally, one quantum dot may have a core / shell structure surrounding another quantum dot. The interface between the core and the shell may have a concentration gradient in which the concentration of the element present in the shell decreases toward the center.

[0173] In some embodiments, the quantum dot may have a core-shell structure comprising a core containing the aforementioned nanocrystal and a shell surrounding the core. The shell of the quantum dot may serve as a protective layer to maintain semiconductor properties by preventing chemical degradation of the core and / or as a charging layer to impart electrophoretic properties to the quantum dot. The shell may be a single layer or a multilayer. The interface between the core and the shell may have a concentration gradient in which the concentration of elements present in the shell decreases toward the center. Examples of the shell of the quantum dot include metal or non-metal oxides, semiconductor compounds, or combinations thereof.

[0174] For example, the oxide of the metal or nonmetal mentioned above may be exemplified as a binary compound such as SiO2, Al2O3, TiO2, ZnO, MnO, Mn2O3, Mn3O4, CuO, FeO, Fe2O3, Fe3O4, CoO, Co3O4, NiO, or a ternary compound such as MgAl2O4, CoFe2O4, NiFe2O4, CoMn2O4, but the present invention is not limited thereto.

[0175] In addition, the above semiconductor compounds may be examples of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, etc., but the present invention is not limited thereto.

[0176] The interface between the core and the shell may have a concentration gradient in which the concentration of elements present in the shell decreases toward the center. Additionally, the semiconductor nanocrystal may have a structure comprising a single semiconductor nanocrystal core and a multilayer shell surrounding it. In one embodiment, the multilayer shell may have two or more layers, e.g., two, three, four, five, or more layers. Two adjacent layers of the shell may have a single composition or different compositions. Each layer in the multilayer shell may have a composition that varies along the radius.

[0177] Quantum dots can have a full width of half maximum (FWHM) of the emission wavelength spectrum of about 45 nm or less, preferably about 40 nm or less, and more preferably about 30 nm or less, and color purity or color reproducibility can be improved in this range. In addition, since the light emitted through these quantum dots is emitted in all directions, the viewing angle can be improved.

[0178] The above quantum dot may have a shell material and a core material having different energy band gaps. For example, the energy band gap of the shell material may be larger than that of the core material. In another embodiment, the energy band gap of the shell material may be smaller than that of the core material. The above quantum dot may have a multilayer shell. In a multilayer shell, the energy band gap of the outer layer may be larger than that of the inner layer (i.e., the layer closest to the core). In a multilayer shell, the energy band gap of the outer layer may be smaller than that of the inner layer.

[0179] Quantum dots can control their absorption / emission wavelengths by adjusting their composition and size. The maximum emission peak wavelength of the quantum dots can have a wavelength range of ultraviolet to infrared or longer.

[0180] The quantum dot may include an organic ligand (e.g., having a hydrophobic residue and / or a hydrophilic residue). The organic ligand residue may be bonded to the surface of the quantum dot. The organic ligand may include RCOOH, RNH2, R2NH, R3N, RSH, R3PO, R3P, ROH, RCOOR, RPO(OH)2, RHPOOH, R2POOH, or a combination thereof, wherein R is independently a C3 to C40 (e.g., C5 or more and C24 or less) substituted or unsubstituted alkyl, a C3 to C40 (e.g., C5 or more and C24 or less) substituted or unsubstituted aliphatic hydrocarbon group such as a C3 to C40 (e.g., substituted or unsubstituted alkenyl), an C6 to C40 (e.g., C6 or more and C20 or less) substituted or unsubstituted aromatic hydrocarbon group such as a C6 to C40 (e.g., C6 or more and C20 or less) substituted or unsubstituted aryl group, or a combination thereof.

[0181] Examples of the above organic ligands include thiol compounds such as methanethiol, ethanethiol, propanethiol, butanethiol, pentanthiol, hexanethiol, octanethiol, dodecanethiol, hexadecanethiol, octadecanethiol, and benzylthiol; amines such as methaneamine, ethaneamine, propaneamine, butanamine, pentylamine, hexylamine, octylamine, nonylamine, decylamine, dodecylamine, hexadecylamine, octadecylamine, dimethylamine, diethylamine, dipropylamine, tributylamine, and trioctylamine; and carboxylic acid compounds such as methanoic acid, ethanoic acid, propanoic acid, butanoic acid, pentanic acid, hexanoic acid, heptanoic acid, octanoic acid, dodecanoic acid, hexadecanoic acid, octadecanic acid, oleic acid, and benzoic acid. Phosphine compounds such as methylphosphine, ethylphosphine, propylphosphine, butylphosphine, pentylphosphine, octylphosphine, dioctylphosphine, tributylphosphine, trioctylphosphine, etc.; phosphine compounds or their oxide compounds such as methylphosphine oxide, ethylphosphine oxide, propylphosphine oxide, butylphosphine oxide, pentylphosphine oxide, tributylphosphine oxide, octylphosphine oxide, dioctylphosphine oxide, trioctylphosphine oxide, etc.; diphenylphosphine, triphenylphosphine compounds or their oxide compounds; C5 to C20 alkyl phosphine acids such as hexylphosphine, octylphosphine, dodecanephosphine, tetradecanephosphine, hexadecanephosphine, octadecanphosphine, etc., and C5 to C20 alkyl phosphonic acids; etc., but are not limited thereto. Quantum dots may include a hydrophobic organic ligand alone or as a mixture of one or more. The hydrophobic organic ligand may not include photopolymerizable residues (e.g., acrylate groups, methacrylate groups, etc.).

[0182] A second insulating layer (P2) may be located on the first color-converting layer (CCL1), the second color-converting layer (CCL2), and the transparent layer (CCL3). The second insulating layer (P2) covers and protects the first color-converting layer (CCL1), the second color-converting layer (CCL2), and the transparent layer (CCL3), thereby preventing foreign substances from entering the first color-converting layer (CCL1), the second color-converting layer (CCL2), and the transparent layer (CCL3). The second insulating layer (P2) may be a single layer or a multilayer, and may be composed of a multilayer with different refractive indices.

[0183] A first color filter (CF1), a second color filter (CF2), and a third color filter (CF3) may be located on the second insulating layer (P2).

[0184] The first color filter (CF1) transmits red light that has passed through the first color conversion layer (CCL1) and absorbs light of the remaining wavelengths, thereby increasing the purity of red light emitted to the outside of the display device. The second color filter (CF2) transmits green light that has passed through the second color conversion layer (CCL2) and absorbs light of the remaining wavelengths, thereby increasing the purity of green light emitted to the outside of the display device. The third color filter (CF3) transmits blue light that has passed through the transmission layer (CCL3) and absorbs light of the remaining wavelengths, thereby increasing the purity of blue light emitted to the outside of the display device.

[0185] A second light-blocking layer (BM2) may be located between the first color filter (CF1), the second color filter (CF2), and the third color filter (CF3). The second light-blocking layer (BM2) may include a light-blocking material or may be in a form in which at least two of the first color filter (CF1), the second color filter (CF2), and the third color filter (CF3) are superimposed.

[0187] Hereinafter, the characteristics of the second electrode according to the comparative example and the embodiment are examined with reference to FIGS. 11 to 13. FIG. 11 is a graph showing the sheet resistance of the second electrode according to the comparative example and the embodiment, FIG. 12 is a graph showing the sheet resistance of the second electrode according to the comparative example and the embodiment, and FIG. 13 is a graph showing the change in sheet resistance of the second electrode according to the comparative example and the embodiment.

[0188] Figure 11 and Table 1 show the sheet resistance of the second electrode according to Comparative Example 1, Comparative Example 2, and Examples 1 to 8 before and after the heat treatment process.

[0189] The second electrode according to Comparative Example 1 comprises two types of metals (AgMg) formed on the electron transport region (Yb), and the second electrode according to Comparative Example 2 comprises one type of metal (Ag) formed on the electron transport region (Yb). The second electrode according to Examples 1 to 4 may comprise a first layer comprising HAT-CN and a metal thin film layer comprising a single metal Ag. Additionally, the second electrode according to Examples 5 to 8 may comprise a first layer comprising HAT-CN, a metal thin film layer comprising a single metal Ag, and a holding layer comprising HAT-CN.

[0190] It can be seen that the second electrode according to Comparative Example 1 contains two types of metals (AgMg), so the change in sheet resistance before and after heat treatment is small and the film quality is formed stably. However, the second electrode according to Comparative Example 1 may have lower characteristics in terms of transmittance or conductivity compared to Comparative Example 2, which contains a single metal.

[0191] In the case of Comparative Example 2, it can be seen that the sheet resistance of the second electrode containing a single metal changes by about 3 ohm / sq due to the heat treatment process. It can be seen that when a single metal layer is formed on an electron transport region containing a metal material as in Comparative Example 2, the stability of the metal layer is significantly reduced.

[0192] In the case of Examples 1 to 4, by providing a second electrode including a first layer containing an organic material, it was confirmed that the change in sheet resistance before and after heat treatment is not significant, despite including a metal thin film layer containing a single metal.

[0193] In the case of Examples 5 to 8, by providing a second electrode including a first layer and a holding layer, it was confirmed that the change in sheet resistance before and after heat treatment was not significant despite including a metal thin film layer containing a single metal.

[0194] The fact that the change in sheet resistance is not large means that in the case of Examples 1 to 8, the metal thin film layer was stably formed through the first layer or the holding layer.

[0195] Before heat treatment After heat treatment condition Average (ohm / sq) Average (ohm / sq) Change (ohm / sq) Comparative Example 1 Yb 10Å / AgMg 100Å 10.9 11.3 0.4 Comparative Example 2 Yb 10Å / Ag 100Å 7.2 10.2 3.0 Example 1 HAT-CN 50Å / Ag 70Å 25.3 26.4 1.1 Example 2 HAT-CN 50Å / Ag 80Å 15.5 16.1 0.6 Example 3 HAT-CN 50Å / Ag 90Å 12.1 12.4 0.3 Example 4 HAT-CN 50Å / Ag 100Å 10.0 10.2 0.2 Example 5 HAT-CN 50Å / Ag 70Å / HAT-CN 10Å 26.9 27.7 0.8 Example 6 HAT-CN 50Å / Ag 80Å / HAT-CN 10Å 15.9 16.4 0.5 Example 7 HAT-CN 50Å / Ag 90Å / HAT-CN 10Å 12.8 13.1 0.3 Example 8 HAT-CN 50Å / Ag 100Å / HAT-CN 10Å 9.6 9.9 0.3

[0196] In addition, as shown in Table 2, it was confirmed that in the case of an example including a first layer and a holding layer, the driving voltage was reduced to about 93% compared to the comparative example, the luminous efficiency was increased to 105%, and the lifespan of the light-emitting element was increased to 105%.

[0197] Driving voltage efficiency life Comparative Example (Yb / AgMg(9.5:0.5)) 100% 100% 100% Example (HAT-CN 50Å / Ag 100Å / HAT-CN 10 Å) 93% 105% 105%

[0198] Referring to FIGS. 12 and 13, the comparative example is a case where the second electrode contains AgMg and the electron transport region contains Yb, with AgMg being 70 Angstroms and 80 Angstroms, respectively. Example 1 is a case where the second electrode contains a first layer (HAT-CN) and a metal thin film layer (Ag), the thickness of the first layer is 20 Angstroms, and the metal thin film layer is 70 Angstroms and 80 Angstroms. Example 2 is a case where the second electrode contains a first layer (HAT-CN), a metal thin film layer (Ag), and a holding layer (HAT-CN), the thickness of the first layer and the holding layer is 20 Angstroms, and the metal thin film layer is 70 Angstroms and 80 Angstroms. In the comparative example, it was confirmed that the sheet resistance changed to approximately 2.87 and 2.65 before and after performing a heat treatment process on the second electrode. On the other hand, it was confirmed that Example 1 showed a change of approximately 0.94 and 0.89, while Example 2 showed a change of -0.01 and -0.05. That is, it was confirmed that the amount of change in sheet resistance was significantly reduced compared to the comparative example when the first layer is included as in Example 1 and when both the first layer and the holding layer are included as in Example 2. The reduction in the amount of change in sheet resistance implies that the film quality of the metal thin film layer is improved, and accordingly, it was confirmed that a stable second electrode can be provided. It is possible to provide a light-emitting device with improved reliability.

[0199] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention. Explanation of the symbols

[0200] E1: First electrode E2: Second electrode EL: Light-emitting unit E2-a: 1st layer E2-b: Metal thin film layer E2-c: Holding layer

Claims

Claim 1 A light-emitting device comprising a first electrode, a second electrode overlapping with the first electrode, and a light-emitting unit located between the first electrode and the second electrode, wherein the second electrode comprises a first layer located on the light-emitting unit and comprising a first organic material, and a metal thin film layer located on the first layer and comprising one type of metal, and wherein the light-emitting unit comprises a light-emitting layer, a hole transport region located between the first electrode and the light-emitting layer, and an electron transport region located between the light-emitting layer and the second electrode, wherein the first layer is disposed on the electron transport region, and the first layer comprises a first metal doped into the first organic material. Claim 2 In claim 1, the first organic material is a light-emitting element that forms a coordination bond with the metal. Claim 3 In claim 1, the first layer comprises at least one of a phenanthroline group, a pyrene group, a furan group, and a thiol group, forming a light-emitting element. Claim 4 delete Claim 5 In claim 1, the light-emitting element further comprises at least one of the first metal, Yb, Li, Cu, Ag, Au, Al, and Mg. Claim 6 In claim 1, the metal of the metal thin film layer comprises any one of Ag, Au, Cu, Al, and Mg, in a light-emitting device. Claim 7 In claim 1, the light-emitting device further comprises a holding layer located on the metal thin film layer, wherein the second electrode is a second electrode. Claim 8 In claim 7, the holding layer comprises a second organic material, and the second organic material forms a coordination bond with the metal of the metal thin film layer. Claim 9 In claim 8, the second organic material is a light-emitting device comprising at least one of a phenanthroline group, a pyrene group, a furan group, and a thiol group. Claim 10 In claim 8, the light-emitting element further comprises a second metal doped into the second organic material in the holding layer. Claim 11 In claim 10, the light-emitting element further comprises at least one of the second metal, Yb, Li, Cu, Ag, Au, Al, and Mg. Claim 12 A display device comprising a substrate, a transistor disposed on the substrate, and a light-emitting element electrically connected to the transistor, wherein the light-emitting element comprises a first electrode, a second electrode superimposed on the first electrode, and a light-emitting unit located between the first electrode and the second electrode, wherein the second electrode comprises a first layer comprising a first organic material located on the light-emitting unit, and a metal thin film layer comprising a metal located on the first layer, wherein the first organic material comprises at least one of a phenanthroline group, a pyrene group, a furan group, and a thiol group, and the first layer further comprises a first metal doped into the first organic material. Claim 13 In paragraph 12, the first organic material is a display device that forms a coordination bond with the metal. Claim 14 delete Claim 15 In paragraph 12, the first metal further comprises at least one of Yb, Li, Cu, Ag, Au, Al, and Mg. A display device. Claim 16 In paragraph 12, the metal of the metal thin film layer comprises any one of Ag, Au, Cu, Al, and Mg in a display device. Claim 17 In claim 12, the second electrode further comprises a holding layer located on the metal thin film layer, and the holding layer comprises a second organic material. Claim 18 In claim 17, the second organic material comprises at least one of a phenanthroline group, a pyrene group, a furan group, and a thiol group, forming a display device. Claim 19 In claim 18, the holding layer further comprises a second metal doped into the second organic material, and the second metal further comprises at least one of Yb, Li, Cu, Ag, Au, Al, and Mg. Claim 20 In claim 17, a display device wherein the thickness of the holding layer is 10 Angstroms to 700 Angstroms.

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