Organic compounds having improved luminsecent properties, organic light emitting diode and organic light emitting device including the compounds

Abstract

The present invention relates to an organic compound having the structure of Chemical Formula 1 below, and to an organic light-emitting diode and an organic light-emitting device in which the organic compound is introduced into a light-emitting layer. The organic compound is a bipolar organic compound having a moiety with p-type characteristics and a moiety with n-type characteristics. The organic compound has high energy levels and a large energy bandgap, and has excellent thermal stability. When the organic compound is introduced into the light-emitting layer of an organic light-emitting diode, holes and electrons combine uniformly across the entire region of the light-emitting material layer, thereby improving the luminous efficiency and luminous lifetime of the light-emitting device. [Chemical Formula 1]

Description

Technology Field

[0001] The present invention relates to organic compounds, and more specifically, to organic compounds having excellent luminescence properties, organic light-emitting diodes containing the same, and organic light-emitting devices. Background Technology

[0002] Organic light-emitting diodes (OLEDs), one of the planar display devices, are attracting attention as light-emitting devices that are rapidly replacing liquid crystal display devices. Organic light-emitting diodes (OLEDs) are formed from thin organic films of less than 2,000 Å, and can realize images in either a single direction or both directions depending on the configuration of the electrodes used. In addition, since OLEDs can be formed on flexible transparent substrates such as plastic, it is easy to realize flexible or foldable display devices. Furthermore, OLED displays have significant advantages over liquid crystal displays, such as the ability to operate at low voltages and excellent color purity.

[0003] Organic light-emitting diodes emit light when holes injected from the anode and electrons injected from the cathode combine in the light-emitting material layer to form excitons, which enter an unstable energy state (excited state) and then return to a stable ground state. Conventional fluorescent materials have low luminescence efficiency because only singlet excitons participate in luminescence. Phosphorescent materials, in which triplet excitons also participate in luminescence, have higher luminescence efficiency compared to fluorescent materials. However, metal complexes, which are representative phosphorescent materials, have limitations in commercialization due to their short luminescence lifetime. Furthermore, organic compounds developed to achieve blue luminescence have the problem of not only having poor luminescence characteristics but also a short luminescence lifetime. The problem to be solved

[0004] The objective of the present invention is to provide an organic compound having a high excited triplet energy level and bipolar characteristics, an organic light-emitting diode and an organic light-emitting device in which said organic compound is introduced into a light-emitting layer.

[0005] Another objective of the present invention is to provide an organic compound having excellent thermal stability and high affinity for charge, and an organic light-emitting diode and an organic light-emitting device in which the organic compound is introduced into a light-emitting layer. means of solving the problem

[0006] According to one aspect, the present invention provides an organic compound having the structure of the following chemical formula 1.

[0007] [Chemical Formula 1]

[0008]

[0009] In Chemical Formula 1, R1 is composed of 3 to 6 aromatic rings and is a condensed heteroaromatic functional group having 1 to 3 nitrogen atoms, C6-C 20 Aromatic amino groups or C4-C 20 It is a heteroaromatic amino group, wherein the condensed heteroaromatic functional group is unsubstituted or C1-C 20 Alkyl group, C6-C 20 Aryl group, C3-C 20 Substituted with a functional group selected from the group consisting of heteroaryl groups and combinations thereof, or forms a spiro structure with a fluorene ring or a xanthen ring; R2 and R3 are each independently light hydrogen, deuterium, tritium, C1-C 20 Alkyl group, C6-C 20 Aryl group and C3-C 20 Selected from the group consisting of heteroaryls, where if a and b are integers greater than or equal to 2, respectively R2 and R3 are identical or different; a and b are the number of substituents, where a is an integer from 0 to 3 and b is an integer from 0 to 4; X and Y are each CR4R5, and R4 and R5 are each independently light hydrogen, deuterium, tritium, C1~C20 Alkyl group, C6~C 30 Aromatic functional groups and C3~C 30 Selected from the group consisting of heteroaromatic functional groups, or R4 and R5 are combined to form C6-C 20 Aromatic ring or C3-C 20 Forms a heteroaromatic ring; m and n are integers of 0 or 1, respectively, and m+n=1; Z is sulfur (S), oxygen (O), or NR6, and R6 is light hydrogen, deuterium, tritium, C1~C 20 Alkyl group, C6~C 30 Aromatic functional groups or C3~C 30 It is a heteroaromatic functional group. Aryl group, C6~C 30 Aralkillgi, C3~C 30 Hetero Aralkilgi, C6~C 30 Aryl oxygroup, C3~C 30 Heteroaryl oxygroup, C6~C 30 aryl amino group or C3~C 30 It is a heteroaryl amino group.

[0010] According to another aspect, the present invention provides an organic light-emitting diode comprising a first electrode, a second electrode facing the first electrode, and at least one light-emitting layer located between the first and second electrodes, wherein the at least one light-emitting layer comprises the organic compound.

[0011] The above organic compound may be included in the electron transport layer, hole blocking layer and / or emitting material layer, and / or charge generation layer of the emitting layer. For example, the above organic compound may be used as a host for the emitting material layer, and the emitting material layer may further include at least one dopant which may be a delayed fluorescent material.

[0012] According to another aspect, the present invention provides an organic light-emitting device, for example, an organic light-emitting lighting device or an organic light-emitting display device, comprising a substrate; and an organic light-emitting diode in which the aforementioned organic compound is introduced into a light-emitting layer. Effects of the invention

[0013] The organic compound of the present invention comprises a condensed aromatic ring containing a benzimidazole moiety and a condensed heteroaromatic ring or (hetero)aromatic amino group connected to the condensed aromatic ring and containing at least one nitrogen atom. Since the benzimidazole moiety has excellent affinity for electrons and thus possesses n-type characteristics, and the condensed heteroaromatic ring or (hetero)aromatic amino group has excellent affinity for holes and thus possesses p-type characteristics, the organic compound of the present invention has bipolar characteristics.

[0014] When the organic compound of the present invention is introduced into a light-emitting layer, for example, a light-emitting material layer, holes and electrons are injected into the light-emitting material layer in a balanced manner, and regions where holes and electrons recombine to emit light are uniformly located across the entire area of ​​the light-emitting material layer. Accordingly, the luminous efficiency of the organic light-emitting diode can be maximized. The organic compound of the present invention contains a condensed aromatic ring containing a benzimidazole moiety, so it has high singlet and triplet energy levels and a large energy bandgap. Therefore, by introducing the organic compound of the present invention into the light-emitting layer, the luminous lifetime of the organic light-emitting diode can be improved. For example, when the organic compound according to the present invention is used as a host for the light-emitting material layer, the exciton energy of the host is efficiently transferred to the dopant, and exciton quenching caused by the interaction between the triplet / singlet excitons of the host or dopant and the surrounding hole (or electron)-polaron is minimized. By applying the organic compound of the present invention to a light-emitting layer, it is possible to realize an organic light-emitting diode with excellent light-emitting efficiency and improved color purity, and an organic light-emitting device. Brief explanation of the drawing

[0015] FIG. 1 is a cross-sectional view schematically illustrating an organic light-emitting display device as an example of an organic light-emitting device according to an exemplary first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of an organic light-emitting diode according to an exemplary first embodiment of the present invention. FIG. 3 is a schematic diagram showing the light emission mechanism of a delayed fluorescent material that may be included in a light-emitting material layer constituting an organic light-emitting diode according to an exemplary embodiment of the present invention. FIG. 4 is a schematic diagram showing the light emission mechanism according to the energy levels between light-emitting materials in a light-emitting material layer constituting an organic light-emitting diode according to an exemplary first embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of an organic light-emitting diode according to an exemplary second embodiment of the present invention. FIG. 6 is a schematic diagram showing the light emission mechanism according to the energy levels between light-emitting materials in a light-emitting material layer constituting an organic light-emitting diode according to an exemplary second embodiment of the present invention. FIG. 7 is a schematic cross-sectional view of an organic light-emitting diode according to an exemplary third embodiment of the present invention. FIG. 8 is a schematic diagram showing the light emission mechanism according to the energy levels between light-emitting materials in a light-emitting material layer constituting an organic light-emitting diode according to an exemplary third embodiment of the present invention. FIG. 9 is a schematic cross-sectional view of an organic light-emitting diode according to an exemplary fourth embodiment of the present invention. FIG. 10 is a schematic diagram showing the light emission mechanism according to the energy levels between light-emitting materials in a light-emitting material layer constituting an organic light-emitting diode according to an exemplary fourth embodiment of the present invention. FIG. 11 is a schematic cross-sectional view of an organic light-emitting diode according to an exemplary fifth embodiment of the present invention. FIG. 12 is a cross-sectional view schematically showing an organic light-emitting display device as an example of an organic light-emitting device according to an exemplary second embodiment of the present invention. FIG. 13 is a schematic cross-sectional view of an organic light-emitting diode according to an exemplary sixth embodiment of the present invention. FIG. 14 is a cross-sectional view schematically showing an organic light-emitting display device as an example of an organic light-emitting device according to an exemplary third embodiment of the present invention. FIG. 15 is a schematic cross-sectional view of an organic light-emitting diode according to an exemplary seventh embodiment of the present invention. FIG. 16 is a schematic cross-sectional view of an organic light-emitting diode according to an exemplary eighth embodiment of the present invention. Specific details for implementing the invention

[0016] The present invention will be described below with reference to the attached drawings, where necessary.

[0017] [Organic Compounds]

[0018] Organic compounds applied to organic light-emitting diodes must possess excellent luminescence characteristics and good affinity for charge, and must maintain stable characteristics even under device operation. In particular, the light-emitting material applied to the organic light-emitting diode is the most important factor determining the device's luminescence efficiency. The light-emitting material must have high quantum efficiency, high electron and hole mobilities, and possess appropriate energy levels relative to other materials applied to the same light-emitting layer and adjacent light-emitting layers.

[0019] The organic compound according to the present invention comprises a condensed aromatic ring containing a benzimidazole moiety having excellent affinity for electrons, and a condensed heteroaromatic ring or (hetero)aromatic amino group connected to the condensed aromatic ring having excellent affinity for holes. The organic compound according to the present invention may have the structure of Formula 1 below.

[0020] [Chemical Formula 1]

[0021]

[0022] In Chemical Formula 1, R1 is composed of 3 to 6 aromatic rings and is a condensed heteroaromatic functional group having 1 to 3 nitrogen atoms, C6-C 20 Aromatic amino groups or C4-C 20 It is a heteroaromatic amino group, wherein the condensed heteroaromatic functional group is unsubstituted or C1-C 20 Alkyl group, C6-C 20 Aryl group, C3-C 20 Substituted with a functional group selected from the group consisting of heteroaryl groups and combinations thereof, or forms a spiro structure with a fluorene ring or a xanthen ring; R2 and R3 are each independently light hydrogen, deuterium, tritium, C1-C 20 Alkyl group, C6-C 20 Aryl group and C3-C 20 Selected from the group consisting of heteroaryls, where if a and b are integers greater than or equal to 2, respectively R2 and R3 are identical or different; a and b are the number of substituents, where a is an integer from 0 to 3 and b is an integer from 0 to 4; X and Y are each CR4R5, and R4 and R5 are each independently light hydrogen, deuterium, tritium, C1~C 20 Alkyl group, C6~C 30 Aromatic functional groups and C3~C 30 Selected from the group consisting of heteroaromatic functional groups, or R4 and R5 are combined to form C6-C 20 Aromatic ring or C3-C 20 Forms a heteroaromatic ring; m and n are integers of 0 or 1, respectively, and m+n=1; Z is sulfur (S), oxygen (O), or NR6, and R6 is light hydrogen, deuterium, tritium, C1~C 20 Alkyl group, C6~C 30 Aromatic functional groups or C3~C 30 It is a heteroaromatic functional group. Aryl group, C6~C 30 Aralkillgi, C3~C 30 Hetero Aralkilgi, C6~C 30 Aryl oxygroup, C3~C 30 Heteroaryl oxygroup, C6~C30 aryl amino group or C3~C 30 It is a heteroaryl amino group.

[0023] Among organic compounds having the structure of Chemical Formula 1, the central condensed aromatic ring contains a benzidimazole moiety having n-type characteristics that induce electron injection and transport due to its excellent affinity for electrons. Meanwhile, the condensed heteroaromatic ring or (hetero)aromatic amino group connected to the central condensed aromatic ring may have p-type characteristics that induce hole injection and transport due to its good affinity for holes. Therefore, organic compounds having the structure of Chemical Formula 1 possess bipolar characteristics.

[0024] According to one exemplary embodiment, the condensed heteroaromatic functional group constituting R1 may be selected from the group consisting of a carbazoleyl moiety, an acridinyl moiety, a dihydroacridinyl moiety, a phenazinyl moiety, and a phenoxazinyl moiety. For example, the carbazoleyl moiety, acridinyl moiety, dihydroacridinyl moiety, phenazinyl moiety, and phenoxazinyl moiety may each include an uncondensed carbazoleyl group, an acridinyl group, a dihydroacridinyl group, a phenazinyl group, a phenoxazinyl group, etc., condensed into a benzene ring, a furan ring, a thiophene ring, an indene ring, or an indole ring, etc.

[0025] In another optional embodiment, the condensed heteroaromatic functional group constituting R1 is not substituted, or C1-C 10 It can be substituted with a functional group selected from the group consisting of alkyl groups, phenyl groups, carbazole groups and combinations thereof, or can form a xanthen ring and a spiro structure.

[0026] Meanwhile, C6~C that can be substituted for R1 in Chemical Formula 1 30The aryl group may be a non-condensed or fused aryl group such as phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, pentanrenyl, indenyl, indenoindenyl, heptalenyl, biphenylenyl, indacenyl, phenalenyl, phenanthrenyl, benzophenanthrenyl, dibenzophenanthrenyl, azulenyl, pyrenyl, fluoranthenyl, triphenylenyl, chrysenyl, tetraphenyl, tetracenyl, plyaenyl, pysenyl, pentaphenyl, pentacenyl, fluorenyl, indenofluorenyl, or spirofluorenyl.

[0027] According to another exemplary embodiment, C3~C that can be substituted for R1 in Formula 1 30 Each heteroaryl group independently consists of pyrrolyl, pyridinyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, tetrazinyl, imidazolyl, pyrazolyl, indoleyl, isoindoleyl, indazolyl, indolezininyl, pyrrolizinyl, carbazoleyl, benzocarbazoleyl, dibenzocarbazoleyl, indolocarbazoleyl, indenocarbazoleyl, benzofurocarbazoleyl, benzothienocarbazoleyl, quinolinyl, isoquinolinyl, phthalazinyl, quinoxalinyl, cinolinyl, quinazolinyl, quinozolinyl, quinozolinyl, quinolidinyl, furinyl, benzoquinolinyl, benzisoquinolinyl, benzoquinazolinyl, benzoquinoxalinyl, acrridinyl, phenanthrolinyl, fermidinyl, phenantridinyl, It may be a non-condensed or condensed heteroaryl group such as pteridinyl, naphtharidinyl, furanyl, pyranyl, oxazinyl, oxazolyl, oxadiazoleyl, triazoleyl, dioxynyl, benzofuranyl, dibenzofuranyl, thiopyranyl, xanthenyl, chromenyl, isochromenyl, thioazinyl, thiophenyl, benzothiophenyl, dibenzothiophenyl, dipuropyrazinyl, benzofurodibenzofuranyl, benzothienobenzothiophenyl, benzothienobenzofuranyl, benzothienodibenzofuranyl, or N-substituted spirofluorenyl.

[0028] In one exemplary embodiment, where R1 is a condensed heteroaromatic functional group such as a carbazoleyl group, an acridinyl group, a dihydroacridinyl group, a phenazinyl group, or a phenoxazinyl group, the condensed heteroaromatic functional group may be further substituted with one to three condensed heteroaromatic functional groups. In this case, the condensed heteroaromatic functional group that may be substituted on R1 may be a carbazoleyl group, an acridinyl group, a dihydroacridinyl group, a phenazinyl group, or a phenoxazinyl group, but is not limited thereto.

[0029] The aryl or heteroaryl group that can be substituted for R1 in Formula 1 may consist of one to three aromatic rings. If the number of aromatic or heteroaromatic rings substituted for R1 in Formula 1 increases, the conjugated structure in the entire organic compound becomes excessively long, which may cause the band gap of the organic compound to decrease excessively. For example, the aryl or heteroaryl group that can be substituted for R1 in Formula 1 includes phenyl, biphenyl, naphthyl, anthracenyl, benzofuranyl, dibenzofuranyl, benzothiophenyl, dibenzothiophenyl, carbazoleyl, acridinyl, phenazinyl, phenoxazinyl, and / or phenothiazinyl, but the present invention is not limited thereto.

[0030] C6-C capable of configuring R2 to R6 30 Aromatic functional groups and C3-C 30 The heteroaromatic functional group is C6-C 30 Aryl group, C3-C 30 Hetero-aryl group, C6-C 30 Aralkilgi, C3-C 30 Hetero Aralkilgi, C6-C 30 aryloxy group, C3-C 30 Heteroaryloxy group, C6-C 30 arylamino group or C3-C 30 It may be a heteroarylamino group. C6-C that can constitute R2 to R5 30 Aromatic functional groups and C3-C 30If the heteroaromatic functional group is an aryl group or a heteroaryl group, it may be the same as the aryl group or heteroaryl group that can be substituted in the aforementioned R1, but is not limited thereto.

[0031] In one exemplary embodiment, the condensed heteroaromatic functional group constituting R1 is not substituted, or C1-C 10 It may be substituted with a functional group selected from the group consisting of alkyl groups, phenyl groups, carbazole groups, and combinations thereof, or may form a xanthen ring and a spiro structure. Additionally, R4 and R5 are each independently light hydrogen, deuterium, tritium, C1-C 10 It may be substituted with a functional group selected from the group consisting of alkyl groups, phenyl groups, and combinations thereof, or R4 and R5 may be combined to form a fluorene ring. Additionally, Z may be sulfur (S).

[0032] As described above, the organic compound having the structure of Chemical Formula 1 comprises a benzimidazole moiety having n-type characteristics and a condensed heteroaromatic moiety or (hetero)aromatic amino group having p-type characteristics. The organic compound of the present invention has a high excited singlet or triplet energy level and excellent thermal stability. When the organic compound of the present invention is introduced into a light-emitting layer, for example, a light-emitting material layer, holes and electrons are injected into the light-emitting material layer in a balanced manner, and a recombination zone in which holes and electrons recombine to emit light can be uniformly located across the entire area of ​​the light-emitting material layer. Accordingly, the luminous efficiency of the organic light-emitting diode can be maximized.

[0033] For example, the organic compound of the present invention can be used as a host for a light-emitting material layer because the energy bandgap between the Highest Occupied Molecular Orbital (HOMO) energy level and the Lowest Unoccupied Molecular Orbital (LUMO) energy level is very wide and the excited triplet energy level is high. When the organic compound according to the present invention is used as a host for a light-emitting material layer, the exciton energy of the host is efficiently transferred to the dopant, and exciton quenching caused by the interaction between the triplet / singlet excitons of the host or dopant and the surrounding hole (or electron)-polaron is minimized.

[0034] For example, the excited triplet energy level of an organic compound having the structure of Formula 1 may be 2.80 eV or higher, preferably 2.90 eV or higher, but the present invention is not limited thereto. In addition, the HOMO energy level of an organic compound having the structure of Formula 1 may be -5.0 to -6.3 eV, the LUMO energy level may be -0.5 to -2.5 eV, and the energy bandgap (Eg) between the HOMO energy level and the LUMO energy level may be 3.0 to 4.7 eV, but the present invention is not limited thereto. Furthermore, since the organic compound having the structure of Formula 1 has excellent affinity for electrons and a low HOMO energy level, it can be applied to an N-type charge generation layer located between the electron transport layer, the hole blocking layer, and / or the light-emitting layer constituting the light-emitting layer.

[0035] In one exemplary embodiment, among the organic compounds having the structure of Formula 1, m may be 1 and n may be 0. For example, such organic compounds may include any one of the organic compounds having the structure of Formula 2 below.

[0036] [Chemical Formula 2]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076] In another exemplary embodiment, among the organic compounds having the structure of Formula 1, m may be 0 and n may be 1. For example, such organic compounds may include any one of the organic compounds having the structure of Formula 3 below.

[0077] [Chemical Formula 3]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107]

[0108]

[0109]

[0110]

[0111]

[0112]

[0113]

[0114]

[0115]

[0116]

[0117]

[0118] [Organic Light Emitting Devices and Organic Light Emitting Diodes]

[0119] By applying any organic compound having the structure of Chemical Formulas 1 to 3 to the light-emitting layer or the light-emitting layer constituting the organic light-emitting diode, it is possible to realize an organic light-emitting diode having a low driving voltage, excellent luminous efficiency, and an improved light-emitting lifespan. The organic light-emitting diode according to the present invention can be applied to organic light-emitting devices such as organic light-emitting display devices or organic light-emitting lighting devices. As an example, a display device to which the organic light-emitting diode of the present invention is applied will be described.

[0120] FIG. 1 is a schematic cross-sectional view of an organic light-emitting display device according to an exemplary first embodiment of the present invention. As shown in FIG. 1, the organic light-emitting display device (100) includes a substrate (110), a thin-film transistor (Tr) located on the substrate (110), and an organic light-emitting diode (D) located on a planarization layer (150) and connected to the thin-film transistor (Tr).

[0121] The substrate (110) may be a glass substrate, a thin flexible substrate, or a polymer plastic substrate. For example, the flexible substrate may be formed from any one of polyimide (PI), polyethersulfone (PES), polyethylenenaphthalate (PEN), polyethylene terephthalate (PET), and polycarbonate (PC). The substrate (110), on which a thin-film transistor (Tr) and an organic light-emitting diode (D) are located, forms an array substrate.

[0122] A buffer layer (122) is formed on a substrate (110), and a thin-film transistor (Tr) is formed on the buffer layer (122). The buffer layer (122) may be omitted.

[0123] A semiconductor layer (120) is formed on top of a buffer layer (122). For example, the semiconductor layer (120) may be made of an oxide semiconductor material. If the semiconductor layer (120) is made of an oxide semiconductor material, a light-blocking pattern (not shown) may be formed on the bottom of the semiconductor layer (120). The light-blocking pattern prevents light from being incident on the semiconductor layer (120), thereby preventing the semiconductor layer (120) from degrading due to light. Optionally, the semiconductor layer (120) may be made of polycrystalline silicon, in which case impurities may be doped at both edges of the semiconductor layer (120).

[0124] A gate insulating film (124) made of an insulating material is formed on the front surface of the substrate (110) on the upper side of the semiconductor layer (120). The gate insulating film (124) is silicon oxide (SiO₂). x ) or silicon nitride (SiN x It can be made of inorganic insulating materials such as ).

[0125] A gate electrode (130) made of a conductive material such as metal is formed on the upper part of the gate insulating film (124) in correspondence with the center of the semiconductor layer (120). In FIG. 1, the gate insulating film (122) is formed on the front surface of the substrate (110), but the gate insulating film (1202) may be patterned in the same shape as the gate electrode (130).

[0126] An interlayer insulating film (132) made of an insulating material is formed on the front surface of the substrate (110) above the gate electrode (130). The interlayer insulating film (132) is silicon oxide (SiO₂). x It can be formed from an inorganic insulating material such as silicon nitride (SiNx) or silicon nitride, or from an organic insulating material such as benzocyclobutene or photoacryl.

[0127] The interlayer insulating film (132) has first and second semiconductor layer contact holes (134, 136) that expose the upper surfaces of both sides of the semiconductor layer (120). The first and second semiconductor layer contact holes (134, 136) are located spaced apart from the gate electrode (130) on both sides of the gate electrode (130). Here, the first and second semiconductor layer contact holes (134, 136) may also be formed within the gate insulating film (122). Optionally, if the gate insulating film (122) is patterned in the same shape as the gate electrode (130), the first and second semiconductor layer contact holes (134, 136) are formed only within the interlayer insulating film (132).

[0128] A source electrode (144) and a drain electrode (146) made of a conductive material such as metal are formed on the upper part of the interlayer insulating film (132). The source electrode (144) and the drain electrode (146) are spaced apart from the gate electrode (130) and contact both sides of the semiconductor layer (120) through the first and second semiconductor layer contact holes (134, 136), respectively.

[0129] A semiconductor layer (120), a gate electrode (130), a source electrode (154), and a drain electrode (156) form a thin-film transistor (Tr), and the thin-film transistor (Tr) functions as a driving element. The thin-film transistor (Tr) illustrated in FIG. 1 has a coplanar structure in which the gate electrode (130), the source electrode (154), and the drain electrode (156) are located on top of the semiconductor layer (120). Alternatively, the thin-film transistor (Tr) may have an inverted staggered structure in which the gate electrode is located on the bottom of the semiconductor layer, and the source electrode and the drain electrode are located on top of the semiconductor layer. In this case, the semiconductor layer may be made of amorphous silicon.

[0130] Although not shown in FIG. 1, a gate wiring and a data wiring intersect to define a pixel region, and a switching element connected to the gate wiring and the data wiring is further formed. The switching element is connected to a thin-film transistor (Tr) which is a driving element. Additionally, a power wiring is formed spaced apart from the data wiring or parallel to the data wiring, and a storage capacitor may be further configured to maintain a constant voltage of the gate electrode of the thin-film transistor (Tr) which is a driving element during one frame.

[0131] Meanwhile, the organic light-emitting display device (100) may include a color filter (not shown) that transmits light generated from an organic light-emitting diode (D). For example, the color filter (not shown) may transmit red (R), green (G), or blue (B) light. In this case, a red, green, and blue color filter pattern that transmits light may be formed in each pixel area. By adopting the color filter (not shown), the organic light-emitting display device (100) can achieve full color. For example, if the organic light-emitting display device (100) is a bottom-emitting type, a color filter (not shown) that transmits light may be located on the upper part of the interlayer insulating film (132) corresponding to the organic light-emitting diode (D1). In another exemplary embodiment, when the organic light-emitting display device (100) is of the top light-emitting type, the color filter (not shown) may be located above the organic light-emitting diode (D), that is, above the second electrode (230).

[0132] A flattening layer (150) is formed on the front surface of the substrate (110) above the source electrode (144) and the drain electrode (146). The flattening layer (150) has a flat upper surface and has a drain contact hole (152) that exposes the drain electrode (146) of the thin-film transistor (Tr). Here, the drain contact hole (152) is shown as being formed directly above the second semiconductor layer contact hole (136), but it may be formed spaced apart from the second semiconductor layer contact hole (136).

[0133] The organic light-emitting diode (D) includes a first electrode (210) located on a flattening layer (150) and connected to the drain electrode (146) of a thin-film transistor (Tr), a light-emitting layer (220) and a second electrode (230) sequentially stacked on the first electrode (210).

[0134] The first electrode (210) is formed separately for each pixel area. The first electrode (210) may be an anode and may be made of a conductive material with a relatively large work function value, for example, a transparent conductive oxide (TCO). Specifically, the first electrode (210) may be made of indium-tin-oxide (ITO), indium-zinc-oxide (IZO), indium-tin-zinc-oxide (ITZO), tin oxide (SnO), zinc oxide (ZnO), indium-copper-oxide (ICO), and aluminum:zinc oxide (Al:ZnO; AZO).

[0135] In the case where the organic light-emitting display device (100) of the present invention is of the bottom-emission type, the first electrode (210) may have a single-layer structure made of a transparent conductive oxide. Meanwhile, in the case where the organic light-emitting display device (100) of the present invention is of the top-emission type, a reflective electrode or a reflective layer may be further formed below the first electrode (210). For example, the reflective electrode or the reflective layer may be made of silver (Ag) or an aluminum-palladium-copper (APC) alloy. In the organic light-emitting diode (D) of the top-emission type, the first electrode (210) may have a triple-layer structure of ITO / Ag / ITO or ITO / APC / ITO. Additionally, a bank layer (160) covering the edge of the first electrode (210) is formed on the planarization layer (150). The bank layer (160) exposes the center of the first electrode (210) corresponding to the pixel area.

[0136] A light-emitting layer (220) is formed on the first electrode (210). In one exemplary embodiment, the light-emitting layer (220) may have a single-layer structure of an emitting material layer (EML). Alternatively, the light-emitting layer (220) may have a plurality of charge transport layers in addition to the emitting material layer. For example, the light-emitting layer (220) may include a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), a hole blocking layer (HBL), an electron transport layer (ETL), and / or an electron injection layer (EIL) (see FIG. 2, 5, 7, 9 and 11). Additionally, the light-emitting part constituting the light-emitting layer (220) may consist of one part, or two or more light-emitting parts may form a tandem structure.

[0137] At this time, the light-emitting layer (220) comprises any organic compound having the structure of Chemical Formulas 1 to 3. For example, any organic compound having the structure of Chemical Formulas 1 to 3 may be applied to the host of the light-emitting material layer, the electron transport layer, the hole blocking layer and / or the N-type charge generation layer.

[0138] A second electrode (230) is formed on the upper surface of the substrate (110) on which the light-emitting layer (220) is formed. The second electrode (230) is located on the front surface of the display area and is made of a conductive material with a relatively small work function value, so it can be used as a cathode. For example, the second electrode (230) may be made of a material with good reflective properties, such as aluminum (Al), magnesium (Mg), calcium (Ca), silver (Ag), or an alloy or combination thereof. When the organic light-emitting display device (100) is of the top-emitting type, the second electrode (230) has a thin thickness and has light transmission (semi-transmission) characteristics.

[0139] On the second electrode (230), an encapsulation film (170) is formed to prevent external moisture from penetrating into the organic light-emitting diode (D). The encapsulation film (170) may have a laminated structure of a first inorganic insulating layer (172), an organic insulating layer (174), and a second inorganic insulating layer (176), but is not limited thereto.

[0140] The organic light-emitting display device (100) may further include a polarizing plate (not shown) to reduce the reflection of external light. For example, the polarizing plate (not shown) may be a circular polarizing plate. If the organic light-emitting display device (100) is a bottom-emitting type, the polarizing plate may be located below the substrate (110). Meanwhile, if the organic light-emitting display device (100) is a top-emitting type, the polarizing plate may be located above the encapsulation film (170). In addition, in the top-emitting type organic light-emitting display device (100), a cover window (not shown) may be attached to the encapsulation film (170) or the polarizing plate (not shown). At this time, if the substrate (110) and the cover window (not shown) are made of a flexible material, a flexible display device may be formed.

[0141] As described above, any organic compound having the structure of Chemical Formulas 1 to 3 is applied to the emitting layer (220) and the charge generation layer of the organic light-emitting diode (D). Since these organic compounds have excellent heat resistance and light-emitting properties, any organic compound having the structure of Chemical Formulas 1 to 3 is applied to the emitting layer (220) to improve the light-emitting efficiency of the organic light-emitting diode (D), reduce power consumption by lowering the driving voltage, and realize an organic light-emitting diode (D) with a long lifespan.

[0142] An organic light-emitting diode to which an organic compound according to the present invention can be applied is described in detail. FIG. 2 is a schematic cross-sectional view of an organic light-emitting diode according to an exemplary first embodiment of the present invention. As shown in FIG. 2, the organic light-emitting diode (D1) according to the first embodiment of the present invention includes a first electrode (210) and a second electrode (230) facing each other, and a light-emitting layer (220) located between the first and second electrodes (210, 230). An organic light-emitting display device (100, see FIG. 1) includes a red pixel region, a green pixel region, and a blue pixel region, and the organic light-emitting diode (D1) may be located in any pixel region among the red, green, and blue pixel regions.

[0143] In an exemplary embodiment, the light-emitting layer (230) includes a light-emitting material layer (EML, 240) located between the first and second electrodes (210, 230). Additionally, the light-emitting layer (220) may include at least one of a hole transport layer (HTL, 260) located between the first electrode (210) and the light-emitting material layer (240), and an electron transport layer (ETL, 270) located between the light-emitting material layer (240) and the second electrode (230). Furthermore, the light-emitting layer (220) may further include at least one of a hole injection layer (HIL, 250) located between the first electrode (210) and the hole transport layer (260), and a hole injection layer (EIL, 280) located between the electron transport layer (270) and the second electrode (230).

[0144] Optionally, the light-emitting layer (220) may further include an electron blocking layer (EBL, 265), which is a first exciton blocking layer located between the hole transport layer (260) and the light-emitting material layer (240), and / or a hole blocking layer (HBL, 275), which is a second exciton blocking layer located between the light-emitting material layer (240) and the electron transport layer (270).

[0145] The first electrode (210) may be an anode that supplies holes to the light-emitting material layer (240). The first electrode (210) is preferably formed of a conductive material having a relatively large work function value, for example, a transparent conductive oxide (TCO). In an exemplary embodiment, the first electrode (210) may be composed of ITO, IZO, ITZO), SnO, ZnO, ICO, and AZO.

[0146] The second electrode (230) may be a negative electrode that supplies electrons to the light-emitting material layer (240). The second electrode (230) may be made of a conductive material with a relatively small work function value, such as Al, Mg, Ca, Ag, or an alloy or combination thereof, which has good reflective properties.

[0147] In the first embodiment of the present invention, the light-emitting material layer (240) may include a first compound and a second compound. For example, the first compound may be a host, and the second compound may be a delayed fluorescent material (first dopant). For example, any one organic compound having the structure of Chemical Formula 1 to Chemical Formula 3 may be used as the host of the light-emitting material layer (240). For example, the light-emitting material layer (240) may emit red, green, blue, etc. The type of the second compound constituting the light-emitting material layer (240), the energy level between the first compound and the second compound, etc. will be described later.

[0148] The hole injection layer (250) is located between the first electrode (210) and the hole transport layer (260), and improves the interface characteristics between the first electrode (210), which is an inorganic material, and the hole transport layer (260), which is an organic material. In one exemplary embodiment, the hole injection layer 250 includes 4,4',4"-Tris(3-methylphenylamino)triphenylamine (MTDATA), 4,4',4"-Tris(N,N-diphenyl-amino)triphenylamine (NATA), 4,4',4"-Tris(N-(naphthalene-1-yl)-N-phenyl-amino)triphenylamine(1T-NATA), 4,4',4"-Tris(N-(naphthalene-2-yl)-N-phenyl-amino)triphenylamine(2T-NATA), Copper phthalocyanine(CuPc), Tris(4-carbazoyl-9-yl-phenyl)amine (TCTA), N,N'-Diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4"-diamine (NPB; NPD), It may be composed of any one of the following compounds: 1,4,5,8,9,11-Hexaazatriphenylenehexacarbonitrile (Dipyrazino[2,3-f:2'3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile; HAT-CN), 1,3,5-Tris[4-(diphenylamino)phenyl]benzene (TDAPB), poly(3,4-ethylenedioxythiphene)polystyrene sulfonate (PEDOT / PSS) and / or N-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine. Depending on the characteristics of the organic light-emitting diode (D1), the hole injection layer (250) may be omitted.

[0149] The hole transport layer (260) is located adjacent to the light-emitting material layer (240) between the first electrode (210) and the light-emitting material layer (240). In one exemplary embodiment, the hole transport layer (260) is N,N'-Diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine; TPD), NPB (NPD), 4,4'-bis(N-carbazolyl)-1,1'-biphenyl(CBP), Poly[N,N'-bis(4-butylpnehyl)-N,N'-bis(phenyl)-benzidine](Poly-TPD), (Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))] (TFB), Di-[4-(N,N-di-p-tolyl-amino)-phenyl]cyclohexane(TAPC), 3,5-Di(9H-carbazol-9-yl)-N,N-diphenylaniline (DCDPA), The present invention may be composed of a compound selected from the group consisting of N-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine and / or N-(biphenyl-4-yl)-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)biphenyl-4-amine, but is not limited thereto.

[0150] An electron transport layer (270) and an electron injection layer (280) may be sequentially stacked between the light-emitting material layer (240) and the second electrode (230). The material forming the electron transport layer (270) requires high electron mobility, and stably supplies electrons to the light-emitting material layer (240) through smooth electron transport. In one exemplary embodiment, the electron transport layer (270) may include any one of an oxadiazole-based compound, a triazole-based compound, a phenanthroline-based compound, a benzoxazole-based compound, a benzothiazole-based compound, a benzimidazole-based compound, or a triazine-based compound.

[0151] More specifically, the electron transport layer 270 is tris-(8-hydroxyquinoline aluminum (Alq3), 2-biphenyl-4-yl-5-(4-t-butylphenyl)-1,3,4-oxadiazole (PBD), spiro-PBD, lithium quinolate (Liq), 1,3,5-Tris(N-phenylbenzimidazol-2-yl)benzene(TPBi), Bis(2-methyl-8-quinolinolato-N1,O8)-(1,1'-biphenyl-4-olato)aluminum(BAlq), 4,7-diphenyl-1,10-phenanthroline(Bphen), 2,9-Bis(naphthalene-2-yl)4,7-diphenyl-1,10-phenanthroline(NBphen), 2,9-Dimethyl-4,7-diphenyl-1,10-phenathroline(BCP), 3-(4-Biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole(TAZ), 4-(Naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole(NTAZ), 1,3,5-Tri(p-pyrid-3-yl-phenyl)benzene(TpPyPB), 2,4,6-Tris(3'-(pyridin-3-yl)biphenyl-3-yl)1,3,5-triazine(TmPPPyTz), Poly[9,9-bis(3'-((N,N-dimethyl)-N-ethylammonium)-propyl)-2,7-fluorene]-alt-2,7-(9,9-dioctylfluorene)](PFNBr), tris(phenylquinoxaline (TPQ) and / or Diphenyl-4-triphenylsilyl-phenylphosphine It may be selected from the group consisting of oxide (TSPO1), etc., but the present invention is not limited thereto.

[0152] In another exemplary embodiment, the electron transport layer (270) may include any organic compound having the structure of Formula 1 to Formula 3. This is because any organic compound having the structure of Formula 1 to Formula 3 has excellent affinity for electrons. In this case, the electron transport layer (270) may use any organic compound having the structure of Formula 1 to Formula 3 alone, or may be used mixed with or doped with the aforementioned electron transport material.

[0153] The electron injection layer (280) is located between the second electrode (230) and the electron transport layer (270), and the lifespan of the device can be improved by improving the characteristics of the second electrode (270). In one exemplary embodiment, the material of the electron injection layer (280) may be an alkali metal halide material such as LiF, CsF, NaF, BaF2, etc., and / or an alkaline earth metal halide material, and / or an organometallic material such as LiQ, lithium benzoate, sodium stearate, etc., but the present invention is not limited thereto.

[0154] Meanwhile, if a hole moves toward the second electrode (230) through the light-emitting material layer (240) or an electron moves toward the first electrode (210) by passing through the light-emitting material layer (240), the light-emitting efficiency and light-emitting lifespan of the organic light-emitting diode may decrease. To prevent this, the organic light-emitting diode (D1) according to the first exemplary embodiment of the present invention has at least one exciton blocking layer located adjacent to the light-emitting material layer (240).

[0155] For example, in the organic light-emitting diode (D1) according to the first embodiment of the present invention, an electron blocking layer (265) capable of controlling and preventing the movement of electrons is located between the hole transport layer (260) and the light-emitting material layer (240). For example, the electron blocking layer 265 includes TCTA, tris[4-(diethylamino)phenyl]amine, N-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine, TAPC, MTDATA, 1,3-Bis(carbazol-9-yl)benzene(mCP), 3,3'-bis(N-carbazolyl)-1,1'-biphenyl(mCBP), CuPc, N,N'-bis[4-[bis(3-methylphenyl)amino]phenyl]-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine(DNTPD), TDAPB, DCDPA and / or It may be composed of 2,8-bis(9-phenyl-9H-carbazol-3-yl)dibenzo[b,d]thiophene), but the present invention is not limited thereto.

[0156] Additionally, a hole blocking layer (275) is positioned as a second exciton blocking layer between the light-emitting material layer (240) and the electron transport layer (270) to prevent the movement of holes between the light-emitting material layer (240) and the electron transport layer (270). In one exemplary embodiment, any one of an oxadiazole compound, a triazole compound, a phenanthroline compound, a benzoxazole compound, a benzothiazole compound, a benzimidazole compound, or a triazine compound that can be used in the electron transport layer (270) may be used as the material for the hole blocking layer (275).

[0157] For example, the hole blocking layer (275) may be composed of a compound selected from the group consisting of BCP, BAlq, Alq3, PBD, Spiro-PBD, Liq, Bis-4,6-(3,5-di-3-pyridylphenyl)-2-methylpyrimidine (B3PYMPM), Bis[2-(diphenylphosphino)phenyl]teeth oxide (DPEPO), 9-(6-9H-carbazol-9-yl)pyridine-3-yl)-9H-3,9'-bicarbazole, TSPO1, and combinations thereof, which has a lower HOMO energy level compared to the material used in the emitting material layer (240).

[0158] In another exemplary embodiment, the hole blocking layer (275) may include any organic compound having the structure of Formula 1 to Formula 3. This is because any organic compound having the structure of Formula 1 to Formula 3 has a low HOMO energy level and thus possesses hole blocking characteristics. In this case, the hole blocking layer (275) may use any organic compound having the structure of Formula 1 to Formula 3 alone, or it may be used mixed with or doped with the aforementioned hole blocking material.

[0159] As briefly described above, the light-emitting material layer (240) constituting the organic light-emitting diode (D1) according to the first embodiment of the present invention comprises a first compound, which is any organic compound having a structure of Chemical Formulas 1 to 3, and a second compound having delayed fluorescence characteristics. In the past, a p-type host with excellent binding characteristics for holes was mainly used in the light-emitting material layer. When a p-type host is applied to the light-emitting material layer (240), because the binding and transport characteristics for holes are superior to those for electrons, a region in which holes and electrons recombine to emit light is formed at the interface between the light-emitting material layer (240) and the hole blocking layer (275). Furthermore, since some of the charges injected into the light-emitting material layer (240) are quenched without recombining with opposite charges and do not contribute to light emission, a problem arises in which the light emission efficiency is reduced.

[0160] On the other hand, any organic compound having the structure of Chemical Formula 1 to Chemical Formula 3 is an amphoteric compound. When any organic compound having the structure of Chemical Formula 1 to Chemical Formula 3 is used as a host for the light-emitting material layer (240), the region where holes and electrons recombine to emit light is uniformly distributed across the entire region of the light-emitting material layer (240), including the interface between the light-emitting material layer (240) and the electron blocking layer (265). In addition, when any organic compound having the structure of Chemical Formula 1 to Chemical Formula 3 is introduced into the light-emitting material layer (240), the loss of charge among the charges injected into the light-emitting material layer (240) that cannot recombine with opposite charges can be minimized, thereby maximizing the light-emitting efficiency of the organic light-emitting diode (D1).

[0161] The external quantum efficiency (EQE; η) of the luminescent material applied to the luminescent material layer extThe efficiency is determined by four factors: the singlet / triplet ratio, the charge balance factor, the radiative quantum efficiency, and the out-coupling efficiency. Since only singlet excitons participate in luminescence in fluorescent materials, the maximum luminescence efficiency of organic light-emitting diodes using fluorescent materials is only about 5%.

[0162] On the other hand, phosphorescent materials have a luminescence mechanism that converts both singlet excitons and triplet excitons into light. Phosphorescent materials convert singlet excitons into triplets through intersystem crossing (ISC). Therefore, using phosphorescent materials that utilize both singlet and triplet excitons can improve the low luminescence efficiency of fluorescent materials. However, blue phosphorescent materials, in particular, have color purity levels that make them difficult to apply to display devices, and their lifespan is also very short, so they fall far short of commercialization standards.

[0163] A delayed fluorescence material has been developed that can solve the problems associated with conventional fluorescent and phosphorescent materials. A representative delayed fluorescence material is a thermally activated delayed fluorescence (TADF) material. FIG. 3 is a schematic diagram showing the light emission mechanism of a delayed fluorescence material that may be included in a light-emitting material layer constituting an organic light-emitting diode according to an exemplary first embodiment of the present invention.

[0164] Excitation singlet energy level (S1) in delayed fluorescent material TD Excitons having ) and excited triplet energy levels (T1 TDExcitons possessing ) move to an intermediate state called the intramolecular charge transfer (ICT) state, and from there transition to the ground state (S0) (S1→ICT←T1). Since compounds in the ICT state have minimal orbital overlap between HOMO and LUMO, the interaction between molecular orbitals in the HOMO state and those in the LUMO state is small. Consequently, changes in the electron spin state do not affect other electrons, and a new charge transfer band (CT band) that does not follow selection rules is formed. When a light-emitting device containing a delayed fluorescent material is driven, the 25% excited singlet energy level (S1) is reached by heat. TD Excitons having ) and 75% excited triplet energy levels (T1 TD Since the exciton having ) transitions to an intermediate state (ICT) and then falls back to the ground state (S0) and emits light, the internal quantum efficiency theoretically becomes 100%.

[0165] In order for energy transitions to occur in both the triplet and singlet states, the delay fluorescence material is excited to the singlet energy level (S1 TD ) and here triplet energy level (T1 TD ) difference (ΔE ST TDThe energy difference between the singlet state and the triplet state must be 0.3 eV or less, for example, between 0.05 and 0.3 eV. Materials with a small energy difference between the singlet state and the triplet state not only exhibit fluorescence as the exciton energy of the original singlet state falls to the ground state, but also undergo Reverse Inter-System Crossing (RISC) where the triplet state is up-converted to a singlet state with higher energy, and exhibit delayed fluorescence as the singlet state transitions to the ground state. To realize delayed fluorescence, the host must be able to induce the exciton of the triplet state in the dopant to participate in luminescence without being quenched (non-radiative extinction), and for this to happen, the energy levels of the host and the delayed fluorescence material must be controlled.

[0166] FIG. 4 is a schematic diagram illustrating the light emission mechanism according to the energy levels between light-emitting materials in a light-emitting material layer constituting an organic light-emitting diode according to an exemplary first embodiment of the present invention. As schematically shown in FIG. 4, the excited triplet energy level (T1) of a first compound, which may be a host included in the light-emitting material layer (EML, 240) H ) and here singlet energy level (S1 H ) are the excited triplet energy levels (T1) of the second compound having delayed fluorescence characteristics, respectively. TD ) and here singlet energy level (S1 TD It must be higher than ). For example, the first compound excited triplet energy level (T1 H ) is the excited triplet energy level (T1) of the second compound TD It can be 0.2 eV or higher than ), preferably 0.3 eV or higher, and more preferably 0.5 eV or higher.

[0167] Excitation triplet energy level of the first compound (T1 H ) and here singlet energy level (S1 H) is the excited triplet energy level (T1) of the second compound TD ) and here singlet energy level (S1 TD If it is not sufficiently higher than ), the excited triplet energy level (T1) of the second compound TD The exciton of ) is at the excited triplet energy level (T1) of the first compound H A reverse charge transfer to ) occurs. Since the triplet excitons undergo non-radiative annihilation in the first compound where triplet excitons cannot emit light, the triplet state excitons of the second compound with delayed fluorescence properties are unable to contribute to luminescence. The excited singlet energy level (S1 of the second compound with delayed fluorescence properties) TD ) and here triplet energy level (T1 TD ) difference (ΔE ST TD ) may be 0.3 eV or less, for example, 0.05 to 0.3 eV (see FIG. 3).

[0168] In addition, it is necessary to appropriately adjust the HOMO and LUMO energy levels of the first and second compounds. For example, the HOMO energy level of the first compound (HOMO H ) and the HOMO energy level of the second compound (HOMO TD ) difference(|HOMO H -HOMO TD |) or the LUMO energy level of the first compound (LUMO H ) and the LUMO energy level of the second compound (LUMO TD ) difference(|LUMO H -LUMO TD |) may preferably be 0.5 eV or less, for example, 0.1 to 0.5 eV.

[0169] When any organic compound having the structure of Chemical Formulas 1 to 3 and a second compound which may be a delayed fluorescent material are used in combination in the light-emitting material layer (240), exciton energy can be transferred to the second compound without energy loss during the light emission process. At this time, exciton quenching caused by the interaction between the exciton of the host, which is any organic compound having the structure of Chemical Formulas 1 to 3, and the surrounding polaron is minimized, and the lifespan of the light-emitting diode device due to electro-oxidation and photo-oxidation can be prevented.

[0170] For example, the second compound may be a delayed fluorescent material that emits blue, green, or red light. In an exemplary embodiment, the second compound, which is a blue delayed fluorescent material that can be used in the light-emitting material layer (240), is 10-(4-(diphenylphosphoryl)phenyl)-10 H-phenoxazine(SPXZPO), 4,4'-(phenylphosphoryl)bis(4,1-phenylene)bis(10H-phenoxazine(DPXZPO), 10,10',10"-(4,4′',4″-phosphoryltris(benzene-4,1-diyl))tris(10H-phenoxazine(TPXZPO), 9,9'-(5-(4,6-diphenyl-1,3,5-triazin-2-yl)-1,3-phenylene)bis(9H-carbazole)(DcZTrz), 9,9',9",9"'-((6-phenyl-1,3,5-triazin-2,4-diyl)bis(benzene-5,3,1-triyl))tetrakis(9H-carbazole)(DDczTrz), 2,7-bis(9,9-dimethylacridin-10(9H)-yl)-9,9-dimethyl-9H-thioxanthene-10,10-dioxide(DMTDAc), 9,9'-(4,4'-sulfonylbis(4,1-phenylene))bis(3,6-dimethoxyl-9H-carbazole)(DMOC-DPS), 10,10'-(4,4'-Sulfonylbis(4,1-phenylene))bis(9,9-dimethyl-9,10-dihydroacridine(DMAC-DPS), 10-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-9,9-dimethyl-9,10-dihydroacridine(DMAC-TRZ), 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracen]-10'-one(ACRSA), 3,6-dibenzoyl-4,5-di(1-methyl-9-phenyl-9H-carbazoyl)-2-ethynylbenzonitrile(Cz-VPN), 9,9',9"-(5-(4,6-diphenyl-1,3,5-triazin-2-yl)benzene-1,2,3-triyl) tris(9H-carbazole)(TcZTrz), 2'-(10H-페녹사진-10-일)-[1,1':3',1"-terphenyl]-5'-carbonitrile(mPTC), bis(4-(9H-3,9'-bicarbazol-9-yl)phenyl)methanone(CC2BP), 9'-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-3,3",6,6"-tetraphenyl-9,3':6',9"-ter-9H-carbazole(BDPCC-TPTA), 9'-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9,3':,6',9"-ter-9H-carbazole(BCC-TPTA), 9-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-3',6'-diphenyl-9H-3,9'-bicarbazole(DPCC-TPTA), 10-(4,6-diphenyl-1,3,5-triazin-2-yl)-10H-phenoxazine(Phen-TRZ), 9-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-9H-carbazole(Cab-Ph-TRZ), 10-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-10H-spiro[acridine-9,9'-fluorene](SpiroAC-TRZ), 4,6-di(9H-carbazol-9-yl)isophthalonitrile(DczIPN), 3CzFCN 및 2,3,4,6-tetra(9H-carbazol-9-yl)-5-fluorobenzonitrile(4CzFCN) 등을 포함하지만, 본 발명이 이에 한정되지 않는다.,

[0171] In another exemplary embodiment, the second compound, which is a green delayed fluorescent material that can be used in the luminescent material layer (240), is 5'-(phenoxazin-10-yl)-[1,1':3',1''-terphenyl]-2'-carbonitrile (oPTC), 2-biphenyl-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (PIC-TRZ), 9,9',9"-(5-(4,6-diphenyl-1,3,5-triazin-2-yl)benzene-1,2,3-triyl)tris(3,6-dimentyl-9H-carbazole (TmCzTrz), 2,5-bis(4-(10H-phenoxazin-10-yl)phenyl)-1,3,4-oxadiazole (2PXZ-OXD). bis(4-(9,9-dimethylacridin-10(9H)-yl)phenyl)methanone(DMAC-BP), 2-(9-phenyl-9H-carbazol-3-yl)-10,10-dioxide-9H-thioxanthen-9-one(TXO-PhCz), 2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile(4CzIPN), 3,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile(4CzPN), 9H-carbazol-9-yl)-5-fluorobenzonitrile(4CzFCN), 6,6-(9H,9'H-[3,3'-bicarbazole]-9,9'-diyl)bis(4-(9H-carbazol-9-yl)isophthalonitrile(33TczPN), 4,5-bis(5H-benzofuro[3,2-c]carbazol-5-yl)phthalonitrile(BFCz-2CN), 4,5-bis(5H-benzo[4,5]thieno[3,2-c]carbazol-5-yl)phthalonitrile(BTCz-2CN), 4,4"-bis(9,9-dimethylacridin-10(9H)-yl)-[1,1':2',1"-terphenyl]-4',It may include 5'-dicarbonitrile (Ac-VPN), 4,4"-di(10H-phenoxazin-10-yl)-[1,1' :2' ,1"-terphenyl]-4',5' -dicarbonitrile (Px-VPN), 5,5'-(9H,9'H-[3,3'-bicarbazole]-9,9'-diyl)diisophthalnonitrile (35IPNDcz), 2,2'-(9H,9'H-[3,3'-bicarbazole]-9,9'-diyl)diisophthalnonitrile (26IPNDcz), 9,9',9"-(5-(4,6-diphenyl-1,3,5-triazin-2-yl)benzene-1,2,3-triyl) tris(9H-carbazole)(TcZTrz) and 32alCTRZ, etc., but the present invention It is not limited to this.

[0172] In another exemplary embodiment, the second compound, which is a red delayed fluorescent material that can be used in the emitting material layer (240), is 1,3-bis[4-(10H-phenoxazin-10-yl)benzoyl]benzene(mPx2BBP), 2,3,5,6-tetrakis(3,6-diphenylcarbazol-9-yl)-1,4-dicyanobenzene(4CzTPN-Ph), 10,10'-(sulfonylbis(4,1-phenylene))bis(5-phenyl-5,10-dihydrophenazine)(PPZ-DPS), 5,10-bis(4-(benzo[d]thiazol-2-yl)phenyl)-5,10-dihydrophenazine(DHPZ-2BTZ), 5,10-bis(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-5,10-dihydrophenazine (DHPZ-2TRZ) and 7,10-bis(4-(diphenylamino)phenyl)-2,3-dicyanopyrazino phenanathrene (TPA-DCPP), etc., are included but not limited thereto.

[0173] When the emitting material layer (240) is composed of a first compound that may be a host and a second compound that may be a delayed fluorescent material, the second compound may be doped into the emitting material layer (240) in a ratio of 10 to 70 weight%, preferably 10 to 50 weight%, more preferably 20 to 50 weight%.

[0174] FIG. 5 is a schematic cross-sectional view of an organic light-emitting diode according to an exemplary second embodiment of the present invention. As shown in FIG. 5, the organic light-emitting diode (D2) according to the second embodiment of the present invention includes a first electrode (210) and a second electrode (23) facing each other, and a light-emitting layer (220A) located between the first and second electrodes (210, 230). For example, the light-emitting layer (220A) includes a light-emitting material layer (240A). The organic light-emitting display device (100, see FIG. 1) includes a red pixel region, a green pixel region, and a blue pixel region, and the organic light-emitting diode (D2) may be located in any pixel region among the red, green, and blue pixel regions.

[0175] The light-emitting layer (220A) may include at least one of a hole transport layer (260) located between the first electrode (210) and the light-emitting material layer (240A), and an electron transport layer (270) located between the light-emitting material layer (240A) and the second electrode (230). Additionally, the light-emitting layer (220A) may further include at least one of a hole injection layer (250) located between the first electrode (210) and the hole transport layer (260), and an electron injection layer (280) located between the electron transport layer (270) and the second electrode (230). Optionally, the light-emitting layer (220A) may further include an electron blocking layer (265), which is a first exciton blocking layer located between the hole transport layer (260) and the light-emitting material layer (240A), and / or a hole blocking layer (275), which is a second exciton blocking layer located between the light-emitting material layer (240A) and the electron transport layer (270). The remaining configuration of the light-emitting layer (220A), excluding the first and second electrodes (210, 230) and the light-emitting material layer (240A), may be substantially the same as in the first embodiment.

[0176] In a second embodiment of the present invention, the light-emitting material layer (240A) comprises a first compound, a second compound, and a third compound. The first compound may be a host, the second compound may be a delayed fluorescent material (first dopant), and the third compound may be a fluorescent material (second dopant). In this case, the first compound may include any organic compound having the structure of Chemical Formula 1 to Chemical Formula 3. When the light-emitting material layer (240A) further comprises a fluorescent material in addition to the delayed fluorescent material, the energy levels between these materials can be adjusted to realize an organic light-emitting diode (D2) with further improved light-emitting efficiency and color purity.

[0177] When only the first compound and the second compound having delayed fluorescence characteristics are introduced into the emitting material layer (240, see FIG. 2), theoretically, an efficiency of up to 100% can be obtained, thereby enabling the realization of internal quantum efficiency equivalent to that of conventional phosphorescent materials containing heavy metals. However, due to the electron donor-electron acceptor coupling structure and structural distortion of the compound having delayed fluorescence characteristics, additional charge transfer transitions (CT transitions) are induced during the luminescence process, resulting in various geometries. Consequently, when the delayed fluorescence material emits light, it has a broad spectrum with a full width at half maximum (FWHM), which has the disadvantage of degrading color purity. Furthermore, the delayed fluorescence material also utilizes triplet exciton energy during the luminescence process, and as each moiety constituting the molecule rotates, it causes Twisted Internal Charge Transfer (TICT). Consequently, the binding strength of the molecule is reduced, which may lead to a decrease in the lifespan of the device.

[0178] In the second embodiment of the present invention, a third compound, which may be a fluorescent or phosphorescent material, is further included in the light-emitting material layer (240A, EML) to prevent a decrease in color purity and device lifespan caused by using a delayed fluorescent material. As schematically shown in FIG. 6, the triplet exciton energy of the second compound having delayed fluorescent properties is converted into singlet exciton energy, and the converted singlet energy of the second compound is transferred to the third compound within the same light-emitting material layer by Forster Resonance Energy Transfer (FRET) to realize hyper-fluorescence.

[0179] When the light-emitting material layer (240A, EML) comprises a first compound which is any organic compound having the structure of Formulas 1 to 3, a second compound which has delayed fluorescence characteristics, and a third compound which is a fluorescent or phosphorescent material, it is necessary to appropriately adjust the energy levels between these materials. FIG. 6 is a schematic diagram showing the light emission mechanism according to the energy levels between light-emitting materials in the light-emitting material layer constituting an organic light-emitting diode according to an exemplary second embodiment of the present invention.

[0180] First, in order to realize delayed fluorescence characteristics, the excited singlet energy level (S1) of the second compound, which is a delayed fluorescent material TD ) and here triplet energy level (T1 TD The difference ) may be 0.3 eV or less (see Fig. 3). Meanwhile, the excited singlet energy level (S1) of the first compound that may be the host H ) and here triplet energy levels (T1 H ) are the excited singlet energy levels (S1) of the second compound, which may each be a delayed fluorescent material. TD ) and here triplet energy levels (T1 TD It is higher than ). For example, the excited triplet energy level (T1) of the first compound. H ) is the excited triplet energy level (T1) of the second compound TD It can be 0.2 eV higher than ), for example 0.3 eV or higher, preferably 0.5 eV or higher.

[0181] In addition, the excited singlet energy level (S1) of the second compound TD ) is the excited singlet energy level (S1) of a third compound that may be a fluorescent or phosphorescent material. FD It must be higher than ). Optionally, the excited triplet energy level (T1 of the second compound) TD ) is the excited triplet energy level (T1) of the third compound FDIt may be higher than ). For example, the first compound that may be the host may be any organic compound having the structure of Formula 1 to Formula 3. The second compound may be the same as that described in the first embodiment.

[0182] Meanwhile, in order to realize superfluorescence, exciton energy must be efficiently transferred from a second compound, which is a delayed fluorescent material, to a third compound, which is a fluorescent or phosphorescent material. For example, a fluorescent or phosphorescent material having an absorption spectrum with a wide overlapping region with the emission spectrum of a second compound having delayed fluorescent properties can be used as the third compound.

[0183] The third compound may emit light in blue, green, or red. In one exemplary embodiment, the fluorescent material that can be used as the third compound may emit light in blue. For example, the third compound may have a pyrene-based, anthracene-based, fluoranthene-based, and boron-based core, but the present invention is not limited thereto. For example, the third compound, which is a fluorescent material emitting light in blue, may comprise any one of the organic compounds having the structure of Chemical Formula 4 below.

[0184] Chemical formula 4

[0185]

[0186]

[0187] In other optional embodiments, the third compound, which is a fluorescent material emitting green light, may have a boron-dipyrromethene (BODIPY; 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) core and / or a quinolino-acridine core, but is not limited thereto. Additionally, a metal complex capable of emitting blue, green, or red light as a phosphorescent material may be used as the third compound.

[0188] In an exemplary embodiment, the weight ratio of the first compound in the light-emitting material layer (240A, EML) may be greater than the weight ratio of the second compound, and the weight ratio of the second compound may be greater than the weight ratio of the third compound. When the weight ratio of the second compound is greater than the weight ratio of the third compound, sufficient energy transfer by the FRET mechanism from the second compound to the third compound may occur. For example, the first compound may be included in the light-emitting material layer (240A, EML) in a ratio of 60 to 75 weight%, the second compound in a ratio of 20 to 40 weight%, and the third compound in a ratio of 0.1 to 5 weight%, but the present invention is not limited thereto.

[0189] FIG. 7 is a cross-sectional view schematically showing an organic light-emitting diode according to an exemplary third embodiment of the present invention, and FIG. 8 is a schematic diagram showing a light-emitting mechanism according to energy levels between light-emitting materials in a light-emitting material layer constituting an organic light-emitting diode according to an exemplary third embodiment of the present invention. As shown in FIG. 7, the organic light-emitting diode (D3) according to an exemplary third embodiment of the present invention includes a first electrode (310) and a second electrode (330) facing each other, and a light-emitting layer (320) located between the first and second electrodes (310, 330).

[0190] In an exemplary embodiment, the light-emitting layer (320) includes a light-emitting material layer (340). The organic light-emitting display device (100, see FIG. 1) includes a red pixel area, a green pixel area, and a blue pixel area, and the organic light-emitting diode (D3) may be located in any pixel area among the red, green, and blue pixel areas. The light-emitting layer (320) may include at least one of a hole transport layer (360) located between the first electrode (310) and the light-emitting material layer (340), and an electron transport layer (370) located between the light-emitting material layer (340) and the second electrode (330). Additionally, the light-emitting layer (320) may further include at least one of a hole injection layer (350) located between the first electrode (310) and the hole transport layer (360), and an electron injection layer (380) located between the electron transport layer (360) and the second electrode (330).

[0191] Optionally, the light-emitting layer (320) may further include an electron blocking layer (365), which is a first exciton blocking layer located between the hole transport layer (360) and the light-emitting material layer (340), and / or a hole blocking layer (375), which is a second exciton blocking layer located between the light-emitting material layer (340) and the electron transport layer (370). The configuration of the light-emitting layer (320), excluding the first electrode (310), the second electrode (330), and the light-emitting material layer (340), may be the same as the first and second embodiments described above.

[0192] The emitting material layer (340) includes a first emitting material layer (EML1, 342, lower emitting material layer, first layer) located between the electron blocking layer (365) and the hole blocking layer (375), and a second emitting material layer (EML2, 344, upper emitting material layer, second layer) located between the first emitting material layer (342) and the hole blocking layer (375). Either of the first emitting material layer (342, EML1) and the second emitting material layer (344, EML2) includes a second compound (first dopant) which is a delayed fluorescent material, and either of the first emitting material layer (342, EML1) and the second emitting material layer (344, EML2) includes a fifth compound (second dopant) which is a fluorescent or phosphorescent material. Additionally, the first light-emitting layer (342, EML1) and the second light-emitting material layer (344, EML2) each include a first compound and a fourth compound, which may be a first host and a second host, respectively. For example, the first light-emitting material layer (342) includes a first compound that may be a host and a second compound that may be a delayed fluorescent material. The second light-emitting material layer (344) includes a fourth compound that may be a second host and a fifth compound that may be a fluorescent or phosphorescent material.

[0193] The first emitting material layer (342, EML1) may be composed of a first compound, which is any organic compound having the structure of Chemical Formulas 1 to 3, and a second compound, which is a delayed fluorescent material. In the second compound, the excited triplet exciton energy of the second compound is converted to the excited singlet exciton energy level by reverse intersystem transition (RISC). While the second compound has high quantum efficiency, its color purity is poor because its full width at half maximum is wide. On the other hand, the second emitting material layer (344, EML2) is composed of a fourth compound, which may be a second host, and a fifth compound, which is a fluorescent or phosphorescent material. For example, the fifth compound, which is a fluorescent material, has an advantage in color purity because its full width at half maximum is narrow compared to the second compound, but it has a limit in quantum efficiency because triplet excitons cannot participate in luminescence.

[0194] However, according to the present embodiment, the excited singlet exciton energy and excited triplet exciton energy of the second compound having delayed fluorescence characteristics included in the first emitting material layer (342, EML1) are transferred to the fifth compound included in the adjacent second emitting material layer (342, EML2) through Forster resonance energy transfer (FRET), which is transferred in a non-radiative form through an electric field due to dipole-dipole interaction, and final luminescence occurs in the fifth compound.

[0195] Due to the inverse intersystem transition phenomenon, the excited triplet exciton energy of the second compound contained in the first emitting material layer (362, EML1) is converted into excited singlet exciton energy. The excited singlet exciton energy of the second compound is transferred to the excited singlet energy level of the fifth compound. The fifth compound contained in the second emitting material layer (344, EML2) emits light using both the excited singlet exciton energy and the excited triplet exciton energy. The exciton energy generated from the second compound, which may be a delayed fluorescent material contained in the first emitting material layer (342, EML1), is efficiently transferred to the fifth compound, which may be a fluorescent or phosphorescent material contained in the second emitting material layer (344, EML2), thereby enabling superfluorescence. At this time, actual light emission occurs in the second emitting material layer (344, EML2) containing the fifth compound, which is a fluorescent or phosphorescent material. Therefore, the quantum efficiency of the organic light-emitting diode (D3) is improved, and as the full width at half maximum is narrowed, the color purity is improved.

[0196] Meanwhile, the first emitting material layer (342, EML1) and the second emitting material layer (344, EML2) each include a first and a fourth compound, which may be the first and second hosts, respectively. The exciton energy generated in the first and fourth compounds, respectively, must be primarily transferred to the second compound, which may be a delayed fluorescent material, to emit light. The excited singlet energy level (S1) of the first compound H1 ) and the excited singlet energy level of the fourth compound (S1 H2 ) and the excited triplet energy level (T1) of the first compound H1 ) and the excited singlet energy level of the fourth compound (T1 H2 ) are the excited singlet energy levels (S1) of the second compound, which may each be a delayed fluorescent material. TD ) and here triplet energy levels (T1 TD It must be higher than ). For example, the excited triplet energy levels (T1) of the first and fourth compounds.H1 , T1 H2 ) is the excited triplet energy level (T1) of the second compound TD It can be at least 0.2 eV higher than ), for example 0.3 eV higher, preferably 0.5 eV higher.

[0197] Meanwhile, the excited singlet energy level (S1) of the fourth compound H2 ) is the excited singlet energy level (S1) of the fifth compound FD It is higher than ). Optionally, the excited triplet energy level (T1) of the fourth compound. H2 ) is the excited triplet energy level (T1) of the fifth compound FD It can be higher than ). Accordingly, the singlet exciton energy generated in the fourth compound can be transferred to the singlet energy of the fifth compound.

[0198] In addition, exciton energy must be efficiently transferred from the second compound, which is converted into an ICT complex state by RISC in the first light-emitting material layer (342, EML1), to the fifth compound, which is a fluorescent or phosphorescent material in the second light-emitting material layer (344, EML2). To realize such an organic light-emitting diode, the excited singlet energy level (S1) of the second compound included in the first light-emitting material layer (342, EML1) TD ) is the excited state singlet energy level (S1) of the fifth compound, which may be a fluorescent or phosphorescent material included in the second emitting material layer (344, EML2). FD It must be higher than ). Optionally, the excited triplet energy level (T1 of the second compound) TD ) is the excited triplet energy level (T1) of the fifth compound FD It can be higher than ).

[0199] In addition, the HOMO energy levels of the first and fourth compounds (HOMO H ) and the HOMO energy level of the second compound (HOMO TD ) difference(|HOMO H -HOMOTD |) or LUMO energy levels of the first and fourth compounds (LUMO H ) and the LUMO energy level of the second compound (LUMO TD ) difference(|LUMO H -LUMO TD |) may be 0.5 eV or less. If these conditions are not satisfied, non-radiative quenching may occur in the second compound, or exciton energy transfer from the first and fourth compounds to the second and fifth compounds may not occur, and the quantum efficiency of the organic light-emitting diode (D3) may decrease.

[0200] The first compound and the fourth compound may be identical or different from each other. For example, the first compound and the fourth compound may each independently comprise any organic compound having the structure of Formula 1 to Formula 3. The second compound, which may be a delayed fluorescent material, may be the same as that described in the first and second embodiments.

[0201] Additionally, the fifth compound may have an emission spectrum with a narrow full width at half maximum and a wide overlap region with the absorption spectrum of the second compound. The fifth compound may be a fluorescent or phosphorescent material that emits blue, green, or red light. For example, the fifth compound may be a fluorescent or phosphorescent material that is blue, green, or green, identical to the third compound described in the second embodiment.

[0202] In each of the first and second light-emitting material layers (342, 344), the first and fourth compounds may have a weight ratio greater than or equal to that of the second and fifth compounds constituting the same light-emitting material layer. Additionally, the weight ratio of the second compound included in the first light-emitting material layer (342, EML1) may be greater than the weight ratio of the fifth compound included in the second light-emitting material layer (344, EML2). Accordingly, energy transfer by FRET from the second compound included in the first light-emitting material layer (342, EML1) to the fifth compound included in the second light-emitting material layer (344, EML2) can occur sufficiently. For example, the second compound in the first light-emitting material layer (342, EML1) may be doped in a ratio of 1 to 70 weight%, preferably 10 to 50 weight%, and more preferably 20 to 50 weight%. The content of the fourth compound in the second light-emitting material layer (344, EML2) may be 90 to 99 weight%, preferably 95 to 99 weight%, and the content of the fifth compound may be 1 to 10 weight%, preferably 1 to 5 weight%.

[0203] Optionally, if a second emitting material layer (344, EML2) is located adjacent to the hole blocking layer (375), the fourth compound constituting the second emitting material layer (344, EML2) may be the same material as the material of the hole blocking layer (375). In this case, the second emitting material layer (344, EML2) may have a hole blocking function along with a light-emitting function. That is, the second emitting material layer (344, EML2) functions as a buffer layer for blocking electrons. Meanwhile, the hole blocking layer (375) may be omitted, and in this case, the second emitting material layer (344, EML2) is used as both a emitting material layer and a hole blocking layer.

[0204] According to another exemplary embodiment, when a second light-emitting material layer (344, EML2) is located adjacent to an electron blocking layer (365), the fourth compound constituting the second light-emitting material layer (344, EML2) may be the same material as the material of the electron blocking layer (365). In this case, the second light-emitting material layer (344, EML2) may have an electron blocking function along with a light-emitting function. That is, the second light-emitting material layer (344, EML2) functions as a buffer layer for blocking electrons. Meanwhile, the electron blocking layer (365) may be omitted, and in this case, the second light-emitting material layer (344, EML2) is used as both a light-emitting material layer and an electron blocking layer.

[0205] Next, an organic light-emitting diode having a light-emitting material layer composed of three layers will be described. FIG. 9 is a schematic cross-sectional view of an organic light-emitting diode according to an exemplary fourth embodiment of the present invention. FIG. 10 is a schematic diagram illustrating the light emission mechanism according to the energy levels between light-emitting materials in the light-emitting material layer constituting the organic light-emitting diode according to an exemplary fourth embodiment of the present invention.

[0206] As shown in FIG. 9, an organic light-emitting diode (D4) according to an exemplary fourth embodiment of the present invention includes a first electrode (410) and a second electrode (430) facing each other, and a light-emitting layer (420) located between the first and second electrodes (410, 430). An organic light-emitting display device (100, see FIG. 1) includes a red pixel region, a green pixel region, and a blue pixel region, and the organic light-emitting diode (D4) may be located in any pixel region among the red, green, and blue pixel regions.

[0207] In an exemplary embodiment, the light-emitting layer (420) includes a light-emitting material layer (440) having a three-layer structure. The light-emitting layer (420) may include at least one of a hole transport layer (460) located between the first electrode (410) and the light-emitting material layer (440), and an electron transport layer (470) located between the light-emitting material layer (440) and the second electrode (430). Additionally, the light-emitting layer (430) may further include at least one of a hole injection layer (450) located between the first electrode (410) and the hole transport layer (460), and a hole injection layer (480) located between the electron transport layer (470) and the second electrode (430). Optionally, the light-emitting layer (420) may further include an electron blocking layer (465), which is a first exciton blocking layer located between the hole transport layer (460) and the light-emitting material layer (440), and / or a hole blocking layer (475), which is a second exciton blocking layer located between the light-emitting material layer (440) and the electron transport layer (450). The remaining configuration of the light-emitting layer (420), excluding the first electrode (410) and the second electrode (430) and the light-emitting material layer (440), may be substantially the same as that described in the first and third embodiments above.

[0208] The light-emitting material layer (440) includes a first light-emitting material layer (442, EML1, intermediate light-emitting material layer, first layer) located between the electron blocking layer (465) and the hole blocking layer (475), a second light-emitting material layer (444, EML2, lower light-emitting material layer, second layer) located between the electron blocking layer (465) and the first light-emitting material layer (442, EML1), and a third light-emitting material layer (446, EML3, upper light-emitting material layer, third layer) located between the first light-emitting material layer (442, EML1) and the hole blocking layer (475).

[0209] The first emitting material layer (442, EML1) comprises a delayed fluorescent material (first dopant), and the second and third emitting material layers (444, 446) each comprise a fifth compound (second dopant) and a seventh compound (third dopant), which may be fluorescent or phosphorescent materials. The first to third emitting material layers (442, 444, 446) also further comprise first, fourth, and sixth compounds, which may each be first to third hosts.

[0210] According to the present embodiment, the excited singlet exciton energy and the excited triplet exciton energy of the second compound, which is a delayed fluorescent material included in the first emitting material layer (442, EML1), are transferred to the fifth compound and the seventh compound, which are fluorescent or phosphorescent materials respectively included in the adjacent second emitting material layer (444, EML2) and third emitting material layer (446, EML3), through a Foster energy transfer FRET, so that final luminescence occurs in the fifth and seventh compounds.

[0211] Due to the reverse inter-system transition phenomenon, the excited triplet exciton energy of the second compound contained in the first emitting material layer (442, EML1) is converted into the excited singlet exciton energy. The excited singlet energy level of the second compound, which is a delayed fluorescent material, is greater than the excited singlet energy level of the fifth and seventh compounds in the second and third emitting material layers (444, 446), which are fluorescent or phosphorescent materials. The excited singlet exciton energy of the second compound contained in the first emitting material layer (442, EML1) is transferred to the excited singlet energy of the fifth and seventh compounds in the adjacent second and third emitting material layers (444 / EML2, 446 / EML3) through the FRET.

[0212] Accordingly, the 5th and 7th compounds of the 2nd and 3rd light-emitting material layers (444, 446) emit light using both singlet exciton energy and triplet exciton energy. The 5th and 7th compounds have a narrower full width at half maximum compared to the 2nd compound. Therefore, the quantum efficiency of the organic light-emitting diode (D4) is improved, and as the full width at half maximum narrows, the color purity is improved. In particular, if the 5th and 7th compounds have an emission wavelength that has a large region overlapping with the absorption wavelength of the 2nd compound, exciton energy can be efficiently transferred from the 2nd compound to the 5th and 7th compounds. At this time, actual light emission occurs in the 2nd and 3rd light-emitting material layers (444, 446) containing the 5th and 7th compounds, respectively.

[0213] In order to achieve efficient luminescence, it is necessary to appropriately adjust the energy levels of the luminescent material introduced into the first to third luminescent material layers (442 / EML1, 444 / EML2, 446 / EML3). Referring to FIG. 10, the excited singlet energy level (S1) of the first compound, which may be the first host H1 ), excited state singlet energy level of the fourth compound that may be the second host (S1 H2 ) and the excited singlet energy level (S1) of the 6th compound which may be the 3rd host H3 ) and the excited triplet energy level (T1) of the first compound H1 ), excited singlet energy level of the 4th compound (T1 H2 ) and the excited triplet energy level (T1) of the 6th compound H3 ) are the excited singlet energy levels (S1) of the second compound, which may each be a delayed fluorescent material. TD ) and here triplet energy levels (T1 TD It must be higher than ).

[0214] Exciton energy must be efficiently transferred from the second compound, which is converted into an ICT complex state by RISC in the first light-emitting material layer (442, EML1), to the fifth and seventh compounds, which are fluorescent or phosphorescent materials added to the second light-emitting material layer (464, EML2) and the third light-emitting material layer (446, EML3), respectively. To realize such an organic light-emitting diode, the excited singlet energy level (S1) of the second compound, which is a delayed fluorescent material included in the first light-emitting material layer (442, EML1) TD ) is the excited singlet energy level (S1) of the 5th and 7th compounds, which may be fluorescent or phosphorescent materials included in the 2nd and 3rd luminescent material layers (444 / EML2, 446 / EML3), respectively. FD1 , S1 FD2 It must be higher than ). Optionally, the excited triplet energy level (T1) of the second compound. TD ) are the excited triplet energy levels (T1) of the 5th and 7th compounds, respectively. FD1 , T1 FD2 It can be higher than ).

[0215] In addition, it is necessary to realize efficient luminescence by preventing the exciton energy transferred from the second compound, which is a delayed fluorescent material, to the fifth and seventh compounds, which are fluorescent or phosphorescent materials, from being transferred to the fourth and sixth compounds, which are the hosts. In relation to this purpose, the excited singlet energy level (S1) of the fourth compound, which may be the second host, and the sixth compound, which may be the third host H2 , S1 H3 ) are the excited singlet energy levels (S1) of the 5th compound and the 7th compound, which may each be fluorescent or phosphorescent materials. FD1 , S1 FD2 It must be higher than ). Optionally, the excited triplet energy levels (T1) of the 4th and 6th compounds H2 , T1 H3) are the excited singlet energy levels (T1) of the 5th compound and the 7th compound, respectively. FD1 , T1 FD2 It can be higher than ).

[0216] As described above, the first to third light-emitting material layers (442 / EML1, 444 / EML2, 446 / EML3) each comprise a first, fourth, and sixth compound that may be a first to third host. The first, fourth, and sixth compounds may be identical or different from each other. For example, the first, fourth, and sixth compounds may each independently comprise an organic compound having a structure of Formula 1 to Formula 3. The second compound, which may be a delayed fluorescent material, may be identical to the second compound described in the first to third embodiments described above.

[0217] Additionally, the 5th and 7th compounds may each have an emission spectrum with a narrow full width at half maximum and a wide overlap region with the absorption spectrum of the 1st dopant. The 5th and 7th compounds may each be fluorescent or phosphorescent materials that emit blue, green, or red light. For example, the 5th and 7th compounds may each be independently fluorescent or phosphorescent materials identical to the 3rd compound in the 2nd embodiment.

[0218] The weight ratio of the second compound included in the first light-emitting material layer (442) may be greater than the weight ratio of the fifth and seventh compounds included in the second and third light-emitting material layers (444, 446), respectively. Accordingly, energy transfer by FRET from the second compound included in the first light-emitting material layer (442) to the fifth and seventh compounds included in the second and third light-emitting material layers (444, 446), respectively, may occur sufficiently. For example, the second compound may be doped in the first light-emitting material layer (442, EML1) at a ratio of 1 to 70 weight%, preferably 10 to 50 weight%, and more preferably 20 to 50 weight%. In the second and third light-emitting material layers (444, 446), the content of the fourth and sixth compounds may be 90 to 99 weight%, preferably 95 to 99 weight%, and the content of the fifth and seventh compounds may be 1 to 10 weight%, preferably 1 to 5 weight%.

[0219] In an optional embodiment, when a second emitting material layer (444 / EML2) is located adjacent to the electron blocking layer (465), the fourth compound constituting the second emitting material layer (444 / EML2) may be the same material as the material of the electron blocking layer (465). In this case, the second emitting material layer (444, EML2) may have an electron blocking function along with a light-emitting function. That is, the second emitting material layer (444, EML2) functions as a buffer layer for blocking electrons. Meanwhile, the electron blocking layer (465) may be omitted, and in this case, the second emitting material layer (444, EML2) is used as both a emitting material layer and an electron blocking layer.

[0220] Additionally, when a third emitting material layer (466, EML3) is located adjacent to the hole blocking layer (475), the sixth compound constituting the third emitting material layer (446, EML3) together with the seventh compound may be the same material as the material of the hole blocking layer (475). In this case, the third emitting material layer (446, EML3) may have a hole blocking function along with a light-emitting function. That is, the third emitting material layer (446, EML3) functions as a buffer layer for blocking holes. Meanwhile, the hole blocking layer (475) may be omitted, and in this case, the third emitting material layer (446, EML3) is used as both a emitting material layer and a hole blocking layer.

[0221] In another exemplary embodiment, the fourth compound constituting the second emitting material layer (444, EML2) may be the same material as the material of the electron blocking layer (465), and the sixth compound constituting the third emitting material layer (446, EML3) may be the same material as the material of the hole blocking layer (475). In this case, the second emitting material layer (444, EML2) may have an electron blocking function along with a light-emitting function, and the third emitting material layer (446, EML3) may have a hole blocking function along with a light-emitting function. That is, the second emitting material layer (444, EML2) and the third emitting material layer (446, EML3) may each function as a buffer layer for electron blocking and a buffer layer for hole blocking. Meanwhile, the electron blocking layer (465) and the hole blocking layer (475) may be omitted, in which case the second light-emitting material layer (444, EML2) is used as a light-emitting material layer and an electron blocking layer, and the third light-emitting material layer (446, EML3) is used as a light-emitting material layer and a hole blocking layer.

[0222] In an optional embodiment, the organic light-emitting diode may include two or more light-emitting parts. FIG. 11 is a schematic cross-sectional view of an organic light-emitting diode according to an exemplary fifth embodiment of the present invention.

[0223] As shown in FIG. 11, the organic light-emitting diode (D5) includes a first electrode (510) and a second electrode (530) facing each other, and a light-emitting layer (520) located between the first and second electrodes (510, 530). The organic light-emitting display device (100, see FIG. 1) includes a red pixel area, a green pixel area, and a blue pixel area, and the organic light-emitting diode (D5) may be located in any pixel area among the red, green, and blue pixel areas. In an exemplary embodiment, the organic light-emitting diode (D5) may be located in the blue pixel area. The first electrode (510) may be an anode, and the second electrode (530) may be a cathode.

[0224] The light-emitting layer (520) includes a first light-emitting part (620) including a first light-emitting material layer (640) and a second light-emitting part (560) including a second light-emitting material layer (740). Additionally, the light-emitting layer (520) may further include a charge-generating layer (680) located between the first light-emitting part (620) and the second light-emitting part (720).

[0225] The charge generating layer (680) is located between the first and second light-emitting parts (620, 720), and the first light-emitting part (620), the charge generating layer (680), and the second light-emitting part (720) are sequentially stacked on the first electrode (510). That is, the first light-emitting part (620) is located between the first electrode (510) and the charge generating layer (680), and the second light-emitting part (720) is located between the second electrode (530) and the charge generating layer (680).

[0226] The first light-emitting part (620) includes a first light-emitting material layer (640, EML1). Additionally, the first light-emitting part (620) may further include at least one of a first hole transport layer (660) located between the first electrode (510) and the first light-emitting material layer (640), a hole injection layer (650) located between the first electrode (510) and the first hole transport layer (660), and a first electron transport layer (670) located between the first light-emitting material layer (640) and the charge generation layer (680). Optionally, the first light-emitting part (620) may further include at least one of a first electron blocking layer (665) located between the first hole transport layer (660) and the first light-emitting material layer (640) and a first hole blocking layer (675) located between the first light-emitting material layer (640) and the first electron transport layer (670).

[0227] The second light-emitting part (720) includes a second light-emitting material layer (740, EML2). Additionally, the second light-emitting part (720) may further include at least one of a second hole transport layer (760) located between the charge generation layer (680) and the second light-emitting material layer (740), a second electron transport layer (770) located between the second light-emitting material layer (740) and the second electrode (530), and an electron injection layer (780) located between the second electron transport layer (770) and the second electrode (530). Optionally, the second light-emitting part (720) may further include at least one of a second electron blocking layer (765) located between the second hole transport layer (760) and the second light-emitting material layer (740), and a second hole blocking layer (775) located between the second light-emitting material layer (740) and the second electron transport layer (770).

[0228] The charge generation layer (680) is located between the first light-emitting part (620) and the second light-emitting part (720). That is, the first light-emitting part (620) and the second light-emitting part (720) are connected by the charge generation layer (680). The charge generation layer (680) may be a PN junction charge generation layer in which an N-type charge generation layer (682) and a P-type charge generation layer (684) are joined.

[0229] The N-type charge generation layer (682) is located between the first electron transport layer (670) and the second hole transport layer (760), and the P-type charge generation layer (684) is located between the N-type charge generation layer (682) and the second hole transport layer (760). The N-type charge generation layer (682) transfers electrons to the first light-emitting material layer (640) of the first light-emitting part (620), and the P-type charge generation layer (684) transfers holes to the second light-emitting material layer (740) of the second light-emitting part (720). In an exemplary aspect, the N-type charge generation layer (682) may include an organic compound having the structure of Chemical Formulas 1 to 3.

[0230] In the present embodiment, the first light-emitting material layer (640) and the second light-emitting material layer (740) may each be a blue, green, or red light-emitting material layer. For example, at least one of the first light-emitting material layer (640) and the second light-emitting material layer (740) comprises a first compound that is a host, a second compound that is a delayed fluorescent material, and a third compound that is optionally a fluorescent or phosphorescent material. For example, the first light-emitting material layer (640) may comprise the first to third compounds.

[0231] When the first light-emitting material layer (640) comprises the first to third compounds, the weight ratio of the first compound may be greater than the weight ratio of the second compound, and the weight ratio of the second compound may be greater than the weight ratio of the third compound. When the weight ratio of the second compound is greater than the weight ratio of the third compound, sufficient energy transfer from the second compound to the third compound may occur. For example, in the first light-emitting material layer (640), the first compound may be included in a ratio of 60 to 75 weight%, the second compound in a ratio of 20 to 40 weight%, and the third compound in a ratio of 0.1 to 5 weight%, but is not limited thereto.

[0232] The second light-emitting material layer (740) may include a first compound that is a host having a structure of Chemical Formulas 1 to 3, identical to the first light-emitting material layer (640), a second compound that is a delayed fluorescent material, and a third compound that is optionally a fluorescent or phosphorescent material. Alternatively, the second light-emitting material layer (740) may include a compound different from at least one of the second compound and the third compound included in the first light-emitting material layer (620), so as to emit light of a different wavelength or have a different light-emitting efficiency than the first light-emitting material layer (640).

[0233] In the drawings, the first light-emitting material layer (640) and the second light-emitting material layer (740) are shown as having a single-layer structure. Alternatively, the first light-emitting material layer (640) and the second light-emitting material layer (740), which may each contain the first to third compounds, may each have a two-layer structure (see FIG. 7) or a three-layer structure (see FIG. 9).

[0234] In the organic light-emitting diode (D5) of the present embodiment, the singlet exciton energy of the second compound, which is a delayed fluorescent material, is transferred to the third compound, which is a fluorescent or phosphorescent material, and final light emission occurs in the third compound. Therefore, the light emission efficiency and color purity of the organic light-emitting diode (D5) are improved. In addition, since the organic light-emitting diode (D5) has a double stack structure of a blue, green, or red light-emitting material layer, the color of the organic light-emitting diode (D5) can be improved or the light emission efficiency can be optimized.

[0235] FIG. 11 is a schematic cross-sectional view of an organic light-emitting display device according to a second embodiment of the present invention. As shown in FIG. 11, the organic light-emitting display device (800) includes a substrate (810) in which first to third pixel regions (P1, P2, P3) are defined, a thin-film transistor (Tr) located on the substrate (810), and an organic light-emitting diode (D) located on the thin-film transistor (Tr) and connected to the thin-film transistor (Tr). For example, the first pixel region (P1) may be a blue pixel region, the second pixel region (P2) may be a green pixel region, and the third pixel region (P3) may be a red pixel region.

[0236] The substrate (810) may be an organic substrate or a flexible substrate. For example, the flexible substrate may be any one of a PI substrate, a PES substrate, a PEN substrate, a PET substrate, and a PC substrate.

[0237] A buffer layer (812) is formed on a substrate (810), and a thin-film transistor (Tr) is formed on the buffer layer (812). The buffer layer (812) may be omitted. As described in FIG. 1, the thin-film transistor (Tr) includes a semiconductor layer, a gate electrode, a source electrode, and a drain electrode, and functions as a driving element.

[0238] A planarization layer (850) is positioned on a thin-film transistor (Tr). The planarization layer (850) has a flat upper surface and has a drain contact hole (852) that exposes the drain electrode of the thin-film transistor (Tr).

[0239] The organic light-emitting diode (D) is located on the planarization layer (850) and includes a first electrode (910) connected to the drain electrode of the thin-film transistor (Tr), a light-emitting layer (920) and a second electrode (930) sequentially stacked on the first electrode (910). The organic light-emitting diode (D) is located in each of the first to third pixel regions (P1, P2, P3) and emits light of different colors. For example, the organic light-emitting diode (D) in the first pixel region (P1) emits blue light, the organic light-emitting diode (D) in the second pixel region (P2) emits green light, and the organic light-emitting diode (D) in the third pixel region (P3) emits red light.

[0240] The first electrode (910) is formed separately for each of the first to third pixel regions (P1, P2, P3), and the second electrode (930) is formed integrally corresponding to the first to third pixel regions (P1, P2, P3).

[0241] The first electrode (910) may be either an anode or a cathode, and the second electrode (930) may be either an anode or a cathode. Additionally, one of the first electrode (910) and the second electrode (930) may be a transmissive electrode (or a semi-transmissive electrode), and the other of the first electrode (910) and the second electrode (930) may be a reflective electrode.

[0242] For example, the first electrode (910) may be an anode and may include a transparent conductive oxide layer made of a conductive material having a relatively large work function value, for example, a transparent conductive oxide (TCO). The second electrode (930) may be a cathode and may include a metal material layer made of a conductive material having a relatively small work function value, for example, a low-resistance metal. For example, the first electrode (910) may include any one of ITO, IZO, ITZO, SnO, ZnO, ICO, and AZO, and the second electrode (930) may be made of Al, Mg, Ca, Ag, or an alloy thereof (e.g., a Mg-Ag alloy) or a combination thereof.

[0243] When the organic light-emitting display device (800) is a bottom light-emitting type, the first electrode (910) may have a single-layer structure of a transparent conductive oxide layer.

[0244] Meanwhile, if the organic light-emitting display device (800) is of the top-emitting type, a reflective electrode or reflective layer may be further formed below the first electrode (910). For example, the reflective electrode or reflective layer may be made of silver or an aluminum-palladium-copper (APC) alloy. In the top-emitting type organic light-emitting diode (D), the first electrode (910) may have a triple-layer structure of ITO / Ag / ITO or ITO / APC / ITO. Additionally, the second electrode (930) may have a thin thickness and possess light-transmitting (semi-transmitting) characteristics.

[0245] A bank layer (860) covering the edge of the first electrode (910) is formed on the flattening layer (850). The bank layer (860) exposes the center of the first electrode (910) corresponding to each of the first to third pixel regions (P1, P2, P3).

[0246] A light-emitting layer (920) is formed on the first electrode (910). The light-emitting layer (920) may have a single-layer structure of a light-emitting material layer (EML). Alternatively, the light-emitting layer (920) may include at least one of a hole injection layer (HIL), a hole transport layer (HTL), and / or an electron blocking layer (EBL) sequentially located between the first electrode (910) and the light-emitting material layer, and a hole blocking layer (HBL), an electron transport layer (ETL), and / or an electron injection layer (EIL) sequentially located between the light-emitting material layer and the second electrode (930).

[0247] In an exemplary aspect, in the first pixel region (P1), which is a blue pixel region, the emitting material layer constituting the emitting layer (930) may include a first compound that is a host, a second compound that is a blue delayed fluorescent material, and optionally a third compound that is a blue fluorescent or phosphorescent material. In the second pixel region (P2), which is a green pixel region, the emitting material layer constituting the emitting layer (930) may include a first compound that is a host, a second compound that is a green delayed fluorescent material, and optionally a third compound that is a green fluorescent or phosphorescent material. In the third pixel region (P3), which is a red pixel region, the emitting material layer constituting the emitting layer (930) may include a first compound that is a host, a second compound that is a red delayed fluorescent material, and optionally a third compound that is a red fluorescent or phosphorescent material. In this case, the light-emitting material layer constituting each of the first to third pixel regions (P3) may have a single-layer structure, a two-layer structure, or a three-layer structure.

[0248] Optionally, the light-emitting material layer constituting the light-emitting layer (930) located in any one of the first to third pixel regions (P1, P2, P3) may include other organic compounds other than the first to third compounds.

[0249] On the second electrode (930), an encapsulation film (870) is formed to prevent external moisture from penetrating into the organic light-emitting diode (D). The encapsulation film (870) may have a triple-layer structure of a first inorganic insulating layer, an organic insulating layer, and a second inorganic insulating layer, but is not limited thereto.

[0250] The organic light-emitting display device (800) may further include a polarizer (not shown) to reduce the reflection of external light. For example, the polarizer (not shown) may be a circular polarizer. If the organic light-emitting display device (800) is a bottom-emitting type, the polarizer may be located below the substrate (810). If the organic light-emitting display device (800) is a top-emitting type, the polarizer may be located above the encapsulation film (870).

[0251] FIG. 13 is a schematic cross-sectional view of an organic light-emitting diode according to an exemplary sixth embodiment of the present invention. The organic light-emitting diode (D6) includes a first electrode (910) and a second electrode (930), and a light-emitting layer (920) located between the first and second electrodes (910, 930).

[0252] The first electrode (910) may be an anode, and the second electrode (930) may be a cathode. For example, the first electrode (910) may be a reflective electrode, and the second electrode (930) may be a transmissive electrode (semi-transmissive electrode).

[0253] The light-emitting layer (920) includes a light-emitting material layer (940). The light-emitting layer (920) may include at least one of a hole transport layer (HTL, 960) located between the first electrode (910) and the light-emitting material layer (940), and an electron transport layer (ETL, 970) located between the light-emitting material layer (940) and the second electrode (930). Additionally, the light-emitting layer (920) may further include at least one of a hole injection layer (HIL, 950) located between the first electrode (910) and the hole transport layer (960), and an electron injection layer (HIL, 980) located between the electron transport layer (970) and the second electrode (930). Optionally, the light-emitting layer (920) may further include at least one of an electron blocking layer (EBL, 965) located between the hole transport layer (960) and the light-emitting material layer (940), and a hole blocking layer (HBL, 975) located between the light-emitting material layer (940) and the electron transport layer (970).

[0254] Additionally, the light-emitting layer (920) may further include an auxiliary hole transport layer (962) located between the hole transport layer (960) and the electron blocking layer (965). The auxiliary hole transport layer (962) may include a first auxiliary hole transport layer (962a) located in the first pixel area (P1), a second auxiliary hole transport layer (962b) located in the second pixel area (P2), and a third auxiliary hole transport layer (962c) located in the third pixel area (P3).

[0255] The first auxiliary hole transport layer (962a) has a first thickness, the second auxiliary hole transport layer (962b) has a second thickness, and the third auxiliary hole transport layer (962c) has a third thickness. At this time, the first thickness is smaller than the second thickness, and the second thickness is smaller than the third thickness. Accordingly, the organic light-emitting diode (D6) has a micro-cavity structure.

[0256] That is, by means of the first to third auxiliary hole transport layers (962a, 962b, 962c) having different thicknesses, the distance between the first electrode (910) and the second electrode (930) in the first pixel area (P1) that emits light (blue) in a first wavelength range is smaller than the distance between the first electrode (910) and the second electrode (930) in the second pixel area (P2) that emits light (green) in a second wavelength range longer than the first wavelength range. In addition, the distance between the first electrode (910) and the second electrode (930) in the second pixel area (P2) that emits light (red) in a third wavelength range longer than the second wavelength range is larger than the distance between the first electrode (910) and the second electrode (930) in the third pixel area (P3) that emits light (red) in a third wavelength range longer than the second wavelength range. Accordingly, the luminous efficiency of the organic light-emitting diode (D6) is improved.

[0257] In FIG. 13, a first auxiliary hole transport layer (962a) is formed in the first pixel region (P1). Alternatively, a microcavity structure can be implemented without the first auxiliary hole transport layer (962a). Additionally, a capping layer (not shown) for enhancing light extraction may be additionally formed on the second electrode (930).

[0258] The light-emitting material layer (940) includes a first light-emitting material layer (942) located in a first pixel area (P1), a second light-emitting material layer (944) located in a second pixel area (P2), and a third light-emitting material layer (946) located in a third pixel area (P3). The first light-emitting material layer (942), the second light-emitting material layer (944), and the third light-emitting material layer (946) may each be a blue light-emitting material layer, a green light-emitting material layer, and a red light-emitting material layer.

[0259] In an exemplary aspect, the first light-emitting material layer (942) of the first pixel area (P1) may comprise a first compound that may be a chemical formula host, a second compound that is a blue delayed fluorescent material, and optionally a third compound that is a blue fluorescent or phosphorescent material. The first compound may be an organic compound having the structure of chemical formulas 1 to 3. The second light-emitting material layer (944) of the second pixel area (P2) may comprise a first compound, a second compound that is a green delayed fluorescent material, and optionally a third compound that is a green fluorescent or phosphorescent material. The third light-emitting material layer (946) of the third pixel area (P3) may comprise a first compound, a second compound that is a red delayed fluorescent material, and optionally a third compound that is a red fluorescent or phosphorescent material.

[0260] At this time, in the first to third light-emitting material layers (942, 944, 946), the weight ratio of the first compound may be greater than the weight ratio of the second compound, and the weight ratio of the second compound may be greater than the weight ratio of the third compound. When the weight ratio of the second compound is greater than the weight ratio of the third compound, sufficient energy transfer from the second compound to the third compound may occur. For example, in the first light-emitting material layer (640), the first compound may be included in a ratio of 60 to 75 weight%, the second compound in a ratio of 20 to 40 weight%, and the third compound in a ratio of 0.1 to 5 weight%, but is not limited thereto.

[0261] In the drawings, the first light-emitting material layer (942), the second light-emitting material layer (944), and the third light-emitting material layer (946) are each shown as having a single-layer structure, but the first to third light-emitting material layers (942, 944, 946) may each have a two-layer structure (see FIG. 7) or a three-layer structure (see FIG. 9).

[0262] In another exemplary aspect, at least one of the first to third light-emitting material layers (942, 944, 946) may comprise the aforementioned first to third compounds, and the remainder may comprise other organic compounds. The first to third light-emitting material layers (942, 944, 946) comprising the first to third compounds may have a single-layer structure, a two-layer structure, or a three-layer structure.

[0263] For example, the first light-emitting material layer (942) of the first pixel area (P1) comprises a first compound that may be a host, a second compound that is a blue delayed fluorescent material, and a third compound that is optionally a blue fluorescent or phosphorescent material. The second light-emitting material layer (944) of the second pixel area (P2) comprises a host and a green dopant, and the third light-emitting material layer (946) of the third pixel area (P3) may comprise a host and a red dopant. In this case, the host of the second light-emitting material layer (944) and / or the third light-emitting material layer (946) may comprise the first compound. The green dopant and the red dopant may each comprise at least one of a green or red phosphorescent material, a green or red fluorescent material, and a green or red delayed fluorescent material.

[0264] The organic light-emitting diode (D6) of FIG. 13 emits blue light, green light, and red light in each of the first to third pixel regions (P1, P2, P3), and accordingly, the organic light-emitting display device (800, see FIG. 12) can realize a color image.

[0265] Meanwhile, the organic light-emitting display device (800) may further include a color filter layer (not shown) corresponding to the first to third pixel areas (P1, P2, P3) to improve color purity. For example, the color filter layer may include a first color filter layer (blue color filter layer, not shown) corresponding to the first pixel area (P1), a second color filter layer (green color filter layer, not shown) corresponding to the second pixel area (P2), and a third color filter layer (red color filter layer, not shown) corresponding to the third pixel area (P3).

[0266] If the organic light-emitting display device (800) is of the bottom light-emitting type, a color filter layer (not shown) may be located between the organic light-emitting diode (D) and the substrate (810). If the organic light-emitting display device (800) is of the top light-emitting type, the color filter layer may be located above the organic light-emitting diode (D).

[0267] FIG. 14 is a schematic cross-sectional view of an organic light-emitting display device according to a third embodiment of the present invention. As shown in FIG. 14, the organic light-emitting display device (1000) includes a substrate (1010) in which first to third pixel regions (P1, P2, P3) are defined, a thin-film transistor (Tr) located on the substrate (1010), an organic light-emitting diode (D) located on the thin-film transistor (Tr) and connected to the thin-film transistor (Tr), and a color filter layer (1020) corresponding to the first to third pixel regions (P1, P2, P3). For example, the first pixel region (P1) may be a blue pixel region, the second pixel region (P2) may be a green pixel region, and the third pixel region (P3) may be a red pixel region.

[0268] The substrate (1010) may be a glass substrate or a flexible substrate. For example, the flexible substrate may be any one of a PI substrate, a PES substrate, a PEN substrate, a PET substrate, and a PC substrate. A thin-film transistor (Tr) is located on the substrate (1010). Alternatively, a buffer layer (not shown) may be formed on the substrate (1010), and the thin-film transistor (Tr) may be formed on the buffer layer. As described through FIG. 1, the thin-film transistor (Tr) includes a semiconductor layer, a gate electrode, a source electrode, and a drain electrode, and functions as a driving element.

[0269] A color filter layer (1020) is positioned on a substrate (1010). For example, the color filter layer (820) may include a first color filter layer (1022) corresponding to a first pixel area (P1), a second color filter layer (1024) corresponding to a second pixel area (P2), and a third color filter layer (1026) corresponding to a third pixel area (P3). The first color filter layer (1022) may be a blue color filter layer, the second color filter layer (1024) may be a green color filter layer, and the third color filter layer (1026) may be a red color filter layer. For example, the first color filter layer (1022) may include at least one of a blue dye and a blue pigment, the second color filter layer (1024) may include at least one of a green dye and a green pigment, and the third color filter layer (1026) may include at least one of a red dye and a red pigment.

[0270] A flattening layer (1050) is positioned on the thin-film transistor (Tr) and the color filter layer (1020). The flattening layer (1050) has a flat upper surface and has a drain contact hole (1052) that exposes the drain electrode (not shown) of the thin-film transistor (Tr).

[0271] The organic light-emitting diode (D) is located on the planarization layer (1050) and corresponds to the color filter layer (1020). The organic light-emitting diode (D) includes a first electrode (1110) connected to the drain electrode (not shown) of a thin-film transistor (Tr), a light-emitting layer (1120) and a second electrode (1130) sequentially located on the first electrode (1110). The organic light-emitting diode (D) emits white light in the first to third pixel regions (P1, P2, P3).

[0272] The first electrode (1110) is formed separately for each of the first to third pixel regions (P1, P2, P3), and the second electrode (1130) is formed integrally corresponding to the first to third pixel regions (P1, P2, P3).

[0273] The first electrode (1110) may be either an anode or a cathode, and the second electrode (1130) may be either an anode or a cathode. Additionally, the first electrode (1110) may be a transmissive electrode, and the second electrode (1130) may be a reflective electrode.

[0274] For example, the first electrode (1110) may be an anode and may include a transparent conductive oxide layer made of a conductive material having a relatively large work function value, for example, a transparent conductive oxide (TCO). The second electrode (1130) may be a cathode and may include a metal material layer made of a conductive material having a relatively small work function value, for example, a low-resistance metal. For example, the transparent conductive oxide layer of the first electrode (1110) may include any one of ITO, IZO, ITZO, SnO, ZnO, ICO, and AZO, and the second electrode (1130) may be made of Al, Mg, Ca, Ag, an alloy thereof (for example, a Mg-Ag alloy), or a combination thereof.

[0275] A light-emitting layer (1120) is formed on the first electrode (1110). The light-emitting layer (1120) includes at least two light-emitting parts that emit different colors. Each light-emitting part may have a single-layer structure of a light-emitting material layer (EML). Alternatively, each light-emitting part may further include at least one of a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), a hole blocking layer (HBL), an electron transport layer (ETL), and an electron injection layer (EIL). Additionally, the light-emitting layer (1120) may further include a charge generation layer (CGL) located between the light-emitting parts.

[0276] At this time, at least one of the two light-emitting parts, the light-emitting material layer (EML), has a structure of Formula 1 to Formula 3 and may include a first compound that is a host, a second compound that is a delayed fluorescent material, and a third compound that is optionally a fluorescent or phosphorescent material.

[0277] A bank layer (1060) covering the edge of the first electrode (1110) is formed on the flattening layer (1050). The bank layer (1060) exposes the center of the first electrode (1110) corresponding to each of the first to third pixel regions (P1, P2, P3). As described above, since the organic light-emitting diode (D) emits white light in the first to third pixel regions (P1, P2, P3), the light-emitting layer (1120) can be formed as a common layer without needing to be separated from the first to third pixel regions (P1, P2, P3). The bank layer (1060) is formed to prevent current leakage at the edge of the first electrode (1110), and the bank layer (1060) may be omitted.

[0278] Although not illustrated, the organic light-emitting display device (1000) may further include an encapsulation film located on the second electrode (1130) to prevent external moisture from penetrating into the organic light-emitting diode (D). Additionally, the organic light-emitting display device (1000) may further include a polarizer located on the lower part of the substrate (1010) to reduce the reflection of external light.

[0279] In the organic light-emitting display device (1000) of FIG. 14, the first electrode (1110) is a transmissive electrode, the second electrode (1130) is a reflective electrode, and the color filter layer (1020) is located between the substrate (1010) and the organic light-emitting diode (D). That is, the organic light-emitting display device (1000) is a bottom light-emitting type. Alternatively, in the organic light-emitting display device (1000), the first electrode (1110) is a reflective electrode, the second electrode (1130) is a transmissive electrode (semi-transmissive electrode), and the color filter layer (1020) can be located on top of the organic light-emitting diode (D).

[0280] In the organic light-emitting display device (1000), the organic light-emitting diode (D) of the first to third pixel areas (P1, P2, P3) emits white light, and by passing through the first to third color filter layers (1022, 1024, 1026), blue, green, and red are displayed in the first to third pixel areas (P1, P2, P3), respectively.

[0281] Although not illustrated, a color conversion layer may be provided between the organic light-emitting diode (D) and the color filter layer (1020). The color conversion layer corresponds to each of the first to third pixel regions (P1, P2, P3) and includes a blue color conversion layer, a green color conversion layer, and a red color conversion layer, and can convert white light emitted from the organic light-emitting diode (D) into blue, green, and red, respectively. For example, the color conversion layer may include quantum dots. Thus, the color purity of the organic light-emitting display device (1000) can be further improved. In an optional embodiment, a color conversion layer may be included instead of the color filter layer (1020).

[0282] FIG. 15 is a schematic cross-sectional view of an organic light-emitting diode according to an exemplary seventh embodiment of the present invention. As shown in FIG. 15, the organic light-emitting diode (D7) comprises a first electrode (1110) and a second electrode (1130) facing each other, and a light-emitting layer (1120) located between the first and second electrodes (1110, 1130). The first electrode (1110) may be an anode, and the second electrode (1130) may be a cathode. For example, the first electrode (1110) may be a transmissive electrode, and the second electrode (1130) may be a reflective electrode.

[0283] The light-emitting layer (1120) includes a first light-emitting part (1220) including a first light-emitting material layer (1240), a second light-emitting part (1320) including a second light-emitting material layer (1340), and a third light-emitting part (1420) including a third light-emitting material layer (1440). Additionally, the light-emitting layer (1120) may further include a first charge-generating layer (1280) located between the first light-emitting part (1220) and the second light-emitting part (1320), and a second charge-generating layer (1380) located between the second light-emitting part (1320) and the third light-emitting part (1420). Accordingly, the first light-emitting part (1220), the first charge-generating layer (1280), the second light-emitting part (1320), the second charge-generating layer (1380), and the third light-emitting part (1420) are sequentially stacked on the first electrode (1110).

[0284] The first light-emitting part (1220) may include any one of a first hole transport layer (HTL1, 1260) located between the first electrode (1110) and the first light-emitting material layer (1240), a hole injection layer (HIL, 1250) located between the first electrode (1110) and the first hole transport layer (1260), and a first electron transport layer (ETL1, 1270) located between the first light-emitting material layer (1240) and the first charge generation layer (1280). Optionally, the first light-emitting part (1220) may further include either a first electron blocking layer (EBL1, 1265) located between the first hole transport layer (1260) and the first light-emitting material layer (1240), or a first hole blocking layer (1275, HBL1) located between the first light-emitting material layer (1240) and the first electron transport layer (1270).

[0285] The second light-emitting part (1320) may include either a second hole transport layer (HTL2, 1360) located between the first charge-generating layer (1280) and the second light-emitting material layer (1340), or a second electron transport layer (ETL2, 1370) located between the second light-emitting material layer (1340) and the second charge-generating layer (1380). Optionally, the second light-emitting part (1220) may further include either a second electron blocking layer (EBL2, 1365) located between the second hole transport layer (1360) and the second light-emitting material layer (1340), or a second hole blocking layer (HBL2, 1375) located between the second light-emitting material layer (1340) and the second electron transport layer (1370).

[0286] The third light-emitting part (1420) may include any one of a third hole transport layer (HTL3, 1460) located between the second charge generation layer (1380) and the third light-emitting material layer (1440), a third electron transport layer (HTL3, 1470) located between the third light-emitting material layer (1440) and the second electrode (1130), and an electron injection layer (HIL, 1480) located between the third electron transport layer (1470) and the second electrode (1130). Optionally, the third light-emitting part (1420) may further include either a third electron blocking layer (EBL3, 1465) located between the third hole transport layer (1460) and the third light-emitting material layer (1440), or a third hole blocking layer (1475) located between the third light-emitting material layer (1440) and the third electron transport layer (1470).

[0287] The first charge generating layer (1280) is located between the first light-emitting part (1220) and the second light-emitting part (1320). That is, the first light-emitting part (1220) and the second light-emitting part (1320) are connected by the first charge generating layer (1280). The first charge generating layer (1280) may be a PN junction charge generating layer in which the first N-type charge generating layer (1282) and the first P-type charge generating layer (1284) are joined.

[0288] The first N-type charge generation layer (1282) is located between the first electron transport layer (1270) and the second hole transport layer (1360), and the first P-type charge generation layer (1284) is located between the first N-type charge generation layer (1282) and the second hole transport layer (1360). The first N-type charge generation layer (1282) transfers electrons to the first light-emitting material layer (1240) of the first light-emitting part (1220), and the first P-type charge generation layer (1284) transfers holes to the second light-emitting material layer (1340) of the second light-emitting part (1320).

[0289] The second charge generation layer (1380) is located between the second light-emitting part (1320) and the third light-emitting part (1420). That is, the second light-emitting part (1420) and the third light-emitting part (1420) are connected by the second charge generation layer (1480). The second charge generation layer (1380) may be a PN junction charge generation layer in which the second N-type charge generation layer (1382) and the second P-type charge generation layer (1384) are joined.

[0290] The second N-type charge generation layer (1382) is located between the second electron transport layer (1370) and the third hole transport layer (1460), and the second P-type charge generation layer (1384) is located between the second N-type charge generation layer (1382) and the third hole transport layer (1460). The second N-type charge generation layer (1382) transfers electrons to the second light-emitting material layer (1340) of the second light-emitting part (1320), and the second P-type charge generation layer (1384) transfers holes to the third light-emitting material layer (1440) of the third light-emitting part (1420). In an exemplary aspect, at least one of the first and second N-type charge generating layers (1284, 1384) may include an organic compound having the structure of Formula 1 to Formula 3.

[0291] In this embodiment, one of the first to third light-emitting material layers (1240, 1340, 1440) is a blue light-emitting material layer, another of the first to third light-emitting material layers (1240, 1340, 1440) is a green light-emitting material layer, and the remainder of the first to third light-emitting material layers (1240, 1340, 1440) may be a red light-emitting material layer.

[0292] For example, the first light-emitting material layer (1240) may be a blue light-emitting material layer, the second light-emitting material layer (1340) may be a green light-emitting material layer, and the third light-emitting material layer (1440) may be a red light-emitting material layer. Alternatively, the first light-emitting material layer (1240) may be a red light-emitting material layer, the second light-emitting material layer (1340) may be a green light-emitting material layer, and the third light-emitting material layer (1440) may be a blue light-emitting material layer. Below, the explanation will focus on the case where the first light-emitting material layer (1240) is a blue light-emitting material layer, the second light-emitting material layer (1340) is a green light-emitting material layer, and the third light-emitting material layer (1440) is a red light-emitting material layer.

[0293] As described below, at least one of the first to third light-emitting material layers (1240, 1340, 1440) may include a first compound, a second compound, and optionally a third compound. The first to third light-emitting material layers (1240, 1340, 1440) containing the first to third compounds may have a single-layer structure, a two-layer structure, or a three-layer structure.

[0294] The first light-emitting material layer (1240) may include a first compound which is a host that may be an organic compound having the structure of Chemical Formulas 1 to 3, a second compound which is a blue delayed fluorescent material, and optionally a third compound which is a blue fluorescent or phosphorescent material. Optionally, the first light-emitting material layer (1240) may include a blue dopant different from the host. The host may include the first compound, and the other blue dopant may include at least one of a blue phosphorescent material, a blue fluorescent material, and a blue delayed fluorescent material.

[0295] The second light-emitting material layer (1340) may include a first compound which is a host that may be an organic compound having the structure of Chemical Formulas 1 to 3, a second compound which is a green delayed fluorescent material, and optionally a third compound which is a green fluorescent or phosphorescent material. Optionally, the second light-emitting material layer (1340) may include a green dopant different from the host. The host includes the first compound, and the other green dopant may include at least one of a green phosphorescent material, a green fluorescent material, and a green delayed fluorescent material.

[0296] The third light-emitting material layer (1440) may include a first compound which is a host that may be an organic compound having the structure of Chemical Formulas 1 to 3, a second compound which is a red delayed fluorescent material, and optionally a third compound which is a red fluorescent or phosphorescent material. Optionally, the third light-emitting material layer (1440) may include a red dopant different from the host. The host may include the first compound, and the other red dopant may include at least one of a red phosphorescent material, a red fluorescent material, and a red delayed fluorescent material.

[0297] For example, when the first to third light-emitting material layers (1240, 1340, 1440) each comprise a first compound, a second compound, and a third compound, the weight ratio of the first compound may be greater than the weight ratio of the second compound, and the weight ratio of the second compound may be greater than the weight ratio of the third compound. When the weight ratio of the second compound is greater than the weight ratio of the third compound, sufficient energy transfer from the second compound to the third compound may occur. For example, in the first to third light-emitting material layers (1240, 1340, 1440), the first compound may be included in a ratio of 60 to 75 weight%, the second compound in a ratio of 20 to 40 weight%, and the third compound in a ratio of 0.1 to 5 weight%, respectively, but is not limited thereto.

[0298] The organic light-emitting diode (D7) emits white light in the first to third pixel regions (P1, P2, P3, see FIG. 14) and passes through a color filter layer (1020, see FIG. 14) formed to correspond to the first to third pixel regions (P1, P2, P3). Accordingly, the organic light-emitting display device (1000, see FIG. 14) can realize a full-color image.

[0299] FIG. 16 is a schematic cross-sectional view of an organic light-emitting diode according to an exemplary eighth embodiment of the present invention. As shown in FIG. 16, the organic light-emitting diode (D8) comprises a first electrode (1110) and a second electrode (1130) facing each other, and a light-emitting layer (1120A) located between the first and second electrodes (1110, 1130).

[0300] The first electrode (1110) may be an anode, and the second electrode (1130) may be a cathode. For example, the first electrode (1110) may be a transmissive electrode, and the second electrode (1130) may be a reflective electrode.

[0301] The light-emitting layer (1120A) includes a first light-emitting part (1520) including a first light-emitting material layer (1540), a second light-emitting part (1620) including a second light-emitting material layer (1640), and a third light-emitting part (1720) including a third light-emitting material layer (1740). Additionally, the light-emitting layer (1120A) may further include a first charge-generating layer (1580) located between the first light-emitting part (1520) and the second light-emitting part (1620), and a second charge-generating layer (1680) located between the second light-emitting part (1620) and the third light-emitting part (1720). Accordingly, the first light-emitting part (1520), the first charge-generating layer (1580), the second light-emitting part (1620), the second charge-generating layer (1680), and the third light-emitting part (1720) are sequentially stacked on the first electrode (1110).

[0302] The first light-emitting part (1520) may include any one of a first hole transport layer (HTL1, 1560) located between the first electrode (1110) and the first light-emitting material layer (1540), a hole injection layer (HIL, 1550) located between the first electrode (1110) and the first hole transport layer (1560), and a first electron transport layer (ETL1, 1570) located between the first light-emitting material layer (1540) and the first charge generation layer (1580). Optionally, the first light-emitting part (1520) may further include either a first electron blocking layer (EBL1, 1565) located between the first hole transport layer (1560) and the first light-emitting material layer (1540), or a first hole blocking layer (1575, HBL1) located between the first light-emitting material layer (1540) and the first electron transport layer (1570).

[0303] The second light-emitting material layer (1640) constituting the second light-emitting part (1620) includes a lower light-emitting material layer (1642) and an upper light-emitting material layer (1644). That is, the lower light-emitting material layer (1642) is located close to the first electrode (1110), and the upper light-emitting material layer (1644) is located close to the second electrode (1130). Additionally, the second light-emitting part (1620) may include either a second hole transport layer (HTL2, 1660) located between the first charge generating layer (1580) and the second light-emitting material layer (1640), or a second electron transport layer (ETL2, 1670) located between the second light-emitting material layer (1640) and the second charge generating layer (1680). Optionally, the second light-emitting part (1620) may further include either a second electron blocking layer (EBL2, 1665) located between the second hole transport layer (1660) and the second light-emitting material layer (1640), or a second hole blocking layer (HBL2, 1675) located between the second light-emitting material layer (1640) and the second electron transport layer (1670).

[0304] The third light-emitting part (1720) may include any one of a third hole transport layer (HTL3, 1760) located between the second charge generation layer (1680) and the third light-emitting material layer (1740), a third electron transport layer (HTL3, 1770) located between the third light-emitting material layer (1740) and the second electrode (1130), and an electron injection layer (HIL, 1780) located between the third electron transport layer (1770) and the second electrode (1130). Optionally, the third light-emitting part (1720) may further include either a third electron blocking layer (EBL3, 1765) located between the third hole transport layer (1760) and the third light-emitting material layer (1740), or a third hole blocking layer (1775) located between the third light-emitting material layer (1740) and the third electron transport layer (1770).

[0305] The first charge generating layer (1580) is located between the first light-emitting part (1520) and the second light-emitting part (1620). That is, the first light-emitting part (1520) and the second light-emitting part (1620) are connected by the first charge generating layer (1580). The first charge generating layer (1580) may be a PN junction charge generating layer in which the first N-type charge generating layer (1582) and the first P-type charge generating layer (1584) are joined. The first N-type charge generation layer (1582) is located between the first electron transport layer (1570) and the second hole transport layer (1660), and the first P-type charge generation layer (1584) is located between the first N-type charge generation layer (1582) and the second hole transport layer (1660).

[0306] The second charge generation layer (1680) is located between the second light-emitting part (1620) and the third light-emitting part (1720). That is, the second light-emitting part (1620) and the third light-emitting part (1720) are connected by the second charge generation layer (1680). The second charge generation layer (1680) may be a PN junction charge generation layer in which the second N-type charge generation layer (1682) and the second P-type charge generation layer (1684) are joined. The second N-type charge generation layer (1682) is located between the second electron transport layer (1670) and the third hole transport layer (1760), and the second P-type charge generation layer (1684) is located between the second N-type charge generation layer (1682) and the third hole transport layer (1760). In an exemplary aspect, at least one of the first and second N-type charge generation layers (1584, 1684) may include an organic compound having the structure of Formula 1 to Formula 3.

[0307] As described below, at least one of the first to third light-emitting material layers (1540, 1640, 1740) may include a first compound, a second compound, and optionally a third compound. The first to third light-emitting material layers (1540, 1640, 1740) containing the first to third compounds may have a single-layer structure, a two-layer structure, or a three-layer structure.

[0308] In the present embodiment, the first emitting material layer (1540) and the third emitting material layer (1740) may each be a blue emitting material layer. In an exemplary aspect, the first emitting material layer (1540) and the third emitting material layer (1740) may each comprise a first compound that is a host, a second compound that is a blue delayed fluorescent material, and a third compound that is optionally a blue phosphorescent or fluorescent material. In an optional embodiment, at least one of the first emitting material layer (1540) and the third emitting material layer (1740) may comprise a blue dopant different from the host. The host may comprise the first compound, and the other blue dopant may comprise at least one of a blue phosphorescent material, a blue fluorescent material, and a blue fluorescent material. The first to third compounds constituting the first light-emitting material layer (1540) and the third light-emitting material layer (1740), and other blue hosts and blue dopants may be the same or different, respectively. For example, the dopant of the first light-emitting material layer (1540) may have a different light-emitting efficiency and / or light-emitting wavelength than the dopant of the third light-emitting material layer (1740).

[0309] One of the lower light-emitting material layer (1642) and the upper light-emitting material layer (1644) constituting the second light-emitting material layer (1640) may be a green light-emitting material layer, and one of the lower light-emitting material layer (1642) and the upper light-emitting material layer (1644) constituting the second light-emitting material layer (1640) may be a red light-emitting material layer. That is, the second light-emitting material layer (1640) is formed by the green light-emitting material layer and the red light-emitting material layer being stacked in succession.

[0310] For example, the lower emitting material layer (1642), which is a green emitting material layer, may include a first compound that is a host, a second compound that is a green delayed fluorescent material, and optionally a third compound that is a green phosphorescent or fluorescent material. In an optional embodiment, the lower emitting material layer (1642), which is a green emitting material layer, may include a green dopant different from the host. The host may include the first compound, and the other green dopant may include at least one of a green phosphorescent material, a green fluorescent material, and a green fluorescent material.

[0311] Meanwhile, the upper light-emitting material layer (1644), which is a red light-emitting material layer, may include a first compound that is a host, a second compound that is a red delayed fluorescent material, and optionally a third compound that is a red phosphorescent or fluorescent material. In an optional embodiment, the upper light-emitting material layer (1644) may include a red dopant different from the host. The host may include the first compound, and the other red dopant may include at least one of a red phosphorescent material, a red fluorescent material, and a red fluorescent material.

[0312] For example, when the first to third light-emitting material layers (1540, 1640, 1740) each comprise a first compound, a second compound, and a third compound, the weight ratio of the first compound may be greater than the weight ratio of the second compound, and the weight ratio of the second compound may be greater than the weight ratio of the third compound. When the weight ratio of the second compound is greater than the weight ratio of the third compound, sufficient energy transfer from the second compound to the third compound may occur. For example, in the first to third light-emitting material layers (1540, 1640, 1740), the first compound may be included in a ratio of 60 to 75 weight%, the second compound in a ratio of 20 to 40 weight%, and the third compound in a ratio of 0.1 to 5 weight%, respectively, but is not limited thereto.

[0313] The organic light-emitting diode (D8) emits white light in all of the first to third pixel regions (P1, P2, P3, see FIG. 14), and by passing through the color filter layer (1020, see FIG. 14) in each of the first to third pixel regions (P1, P2, P3), the organic light-emitting display device (1000, see FIG. 14) can realize a full-color image.

[0314] In FIG. 16, the organic light-emitting diode (D8) has a triple stack structure including first and third light-emitting material layers (1540, 1740), each of which is a blue light-emitting material layer, and first to third light-emitting parts (1520, 1620, 1720). Alternatively, either of the first and third light-emitting parts (1520, 1720) including the first and third light-emitting material layers (1540, 1740) may be omitted, and the organic light-emitting diode (D8) may have a double stack structure.

[0315] The present invention will be explained below through exemplary embodiments, but the present invention is not limited to the technical concept described in the following embodiments.

[0316] Synthesis Example 1: Synthesis of Compound 1-1

[0317] (1) Synthesis of intermediate B

[0318]

[0319] 4.48 g (0.013 mol) of compound A, 2.0 g (0.012 mol) of carbazole, and K3PO4 were dissolved in 60 mL of toluene, and then stirred for 20 minutes under nitrogen purging. 460 mg (20 mol%) of CuI and (±)- trans 0.72 mL (50 mol%) of -1,2-diaminocyclohexane (DACH) was added to a reactor and stirred at 110°C for 8 hours. The reactor was cooled to room temperature, the reaction solvent was removed, and the mixture was purified by column chromatography to obtain 1.9 g (yield: 42%) of intermediate B, a white solid. 1H NMR (500 MHz, CDCl3): δ (ppm) 8.13 (d, J = 7.9 Hz, 2H), 8.02 (d, J = 2.4 Hz, 1H), 7.89 (d, J = 8.5 Hz, 1H), 7.55 (dd, J = 8.5, 2.7 Hz, 1H), 7.42 (ddd, J = 8.2, 7.1, 0.9 Hz, 3H), 7.37 (d, J = 8.2 Hz, 3H), 7.33-7.28 (m, 2H), 3.94 (s, 3H).

[0320] (2) Synthesis of intermediate C

[0321]

[0322] 0.22 g (0.006 mol) of LiAlH4 was dissolved in 10 mL of THF under nitrogen conditions and cooled to 0°C. 2.0 g (0.005 mol) of intermediate B was dissolved in 15 mL of THF and slowly added dropwise to the reaction solution. After stirring for 20 minutes at the same temperature, the solvent was removed by extraction with ethyl acetate. After removing the solvent, the solution was purified by column chromatography to obtain 1.7 g (yield: 92%) of intermediate C, a white solid. 1 H NMR (500 MHz, CDCl3): δ (ppm) 8.13 (dt, J = 7.9, 1.0 Hz, 2H), 7.75 (d, J = 8.2 Hz, 1H), 7.73 (d, J = 2.4 Hz, 1H), 7.43-7.35 (m, 5H), 7.31-7.26 (m, 2H), 4.84 (d, J = 6.1 Hz, 2H), 2.05 (t, J = 6.1 Hz, 1H).

[0323] (3) Synthesis of intermediate D

[0325]

[0326] 1.8 g (0.005 mol) of intermediate C and 2.3 g (0.041 mol) of KOH were dissolved in 15 mL of methylene chloride and then cooled to 0°C while stirring. p 1.17 g (0.006 mol) of -toluene-sulfonyl chloride was dissolved in 10 mL of methylene chloride and slowly added dropwise to the reaction solution. After stirring for 20 minutes at the same temperature, the reaction mixture was further stirred at room temperature for 4 hours. The solvent was removed by extraction with CH2Cl2. After removing the solvent, the solution was purified by column chromatography to obtain 2.2 g (yield: 85%) of the white solid intermediate D. 1 H NMR (500 MHz, CDCl3): δ (ppm) 8.13 (d, J = 7.6 Hz, 2H), 7.81 (d, J = 8.2 Hz, 2H), 7.73 (d, J = 8.5 Hz, 1H), 7.54 (d, J = 2.4 Hz, 1H), 7.44-7.38 (m, 3H), 7.33-7.29 (m, 4H), 7.29-7.27 (m, 2H), 5.23 (s, 2H), 2.35 (s, 3H).

[0327] (4) Synthesis of Compound 1-1

[0329]

[0330] 1H 0.5 g (0.003 mol) of -benzo[d]imidazole-2-thiol, 63 mg (10 mol%) of CuI, and 2.17 g (0.007 mol) of Cs2CO3 were dissolved in 20 mL of DMF and stirred under nitrogen for 20 minutes. 1.68 g (0.003 mol) of intermediate D and L-77 mg (20 mol%) of proline was dissolved in 20 mL of DMF and slowly added dropwise to the reaction solution. After stirring at 160°C for 8 hours, the reactor was cooled to room temperature, and the solvent was removed by extraction with EtOAc. Purification was performed using column chromatography to obtain 1.2 g (yield: 89%) of compound 1-1, a white solid. 1 H NMR (500 MHz, CDCl3): δ (ppm) 8.18-8.14 (m, 2H), 8.07 (d, J = 8.5 Hz, 1H), 7.91-7.86 (m, 1H), 7.82-7.77 (m, 1H), 7.68 (dd, J = 8.5, 2.1 Hz, 1H), 7.61 (d, J = 2.1 Hz, 1H), 7.47-7.41 (m, 4H), 7.39-7.35 (m, 2H), 7.34-7.29 (m, 2H), 4.10 (s, 2H).

[0331] Synthesis Example 2: Synthesis of Compound 1-2

[0332] (1) Synthesis of intermediate E

[0333]

[0334] 4.50 g (0.013 mol), 9 of compound A in the same manner as the synthesis of intermediate B H 4.0 g (0.012 mol) of -3,9'-bicarbazole was reacted to obtain 3.0 g (yield: 46%) of intermediate E, which is a white solid. 1 H NMR (500 MHz, CDCl3): δ (ppm) 8.29-8.27 (m, 1H), 8.20-8.16 (m, 2H), 8.12-8.10 (m, 1H), 7.95 (d, J = 8.5 Hz, 1H), 7.64 (dd, J = 8.2, 2.6 Hz, 1H), 7.56 (dd, J= 2.1, 1.2 Hz, 2H), 7.50-7.48 (m, 1H), 7.45-7.37 (m, 6H), 7.36-7.27 (m, 3H), 3.98 (s, 3H).

[0335] (2) Synthesis of intermediate F

[0336]

[0337] In the same way as the synthesis of intermediate C Using 2.0 g (0.004 mol) of intermediate E, 1.6 g (yield: 84%) of intermediate F, which is a white solid, was finally obtained. 1 H NMR (500 MHz, CDCl3): δ (ppm) 8.29-8.26 (m, 1H), 8.18 (d, J = 7.6 Hz, 2H), 8.10 (d, J = 7.6 Hz, 1H), 7.84-7.79 (m, 2H), 7.59-7.52 (m, 2H), 7.50-7.37 (m, 7H), 7.34-7.27 (m, 3H), 4.88 (d, J = 6.1 Hz, 2H), 2.12 (t, J = 6.1 Hz, 1H).

[0338] (3) Synthesis of intermediate G

[0340]

[0341] In the same way as the synthesis of intermediate D Using 2.2 g (0.004 mol) of intermediate F, 2.5 g (yield: 88%) of intermediate G, which is a white solid, was finally obtained. 1 H NMR (500 MHz, CDCl3): δ (ppm) 8.28 (d, J = 1.5 Hz, 1H), 8.19 (d, J = 7.9 Hz, 2H), 8.11 (d, J = 7.6 Hz, 1H), 7.87-7.84 (m, 2H), 7.82 (d, J = 8.2 Hz, 1H), 7.68 (d,J = 2.4 Hz, 1H), 7.58-7.54 (m, 1H), 7.53-7.29 (m, 13H).

[0342] (4) Synthesis of Compound 1-2

[0344]

[0345] In the same way as the synthesis of Compound 1 1H 0.5 g (0.003 mol) of -benzo[d]imidazole-2-thiol and 2.23 g (0.003 mol) of intermediate G were reacted to finally obtain 1.6 g (yield: 85%) of compound 1-2, which is a white solid. 1 H NMR (500 MHz, CDCl3): δ (ppm) 8.30 (d, J = 1.8Hz, 1H), 8.20-8.16 (m, 2H), 8.15-8.10 (m, 2H), 7.93-7.88 (m, 1H), 7.83-7.78 (m, 1H), 7.76 (dd, J = 8.5, 2.4 Hz, 1H), 7.69 (d, J = 2.1 Hz, 1H), 7.62 (d, J = 8.5 Hz, 1H), 7.57 (dd, J = 8.7, 2.0 Hz, 1H), 7.53-7.47 (m, 2H), 7.43-7.37 (m, 6H), 7.36-7.33 (m, 1H), 7.32-7.26 (m, 2H), 4.14 (s, 2H).

[0346] Synthesis Example 3: Synthesis of Compounds 2-5

[0347] (1) Synthesis of intermediate I

[0348]

[0349] 10.0 g (0.031 mol) of compound H, 4.6 g (0.031 mol) of 1H-benzo[d]imidazole-2-thiol, 0.5 g (0.003 mol) of FeCl3, and 20 g (0.061 mol) of Cs2CO3 were dissolved in 60 mL of DMF under nitrogen conditions. After stirring at 160°C for 24 hours, 10 mL of AcOH was added dropwise to the reaction solution, and the mixture was stirred at the same temperature for 2 hours. The reactor was cooled to room temperature and extracted with methylene chloride. After removing the solvent, the solution was purified by column chromatography to obtain 6.0 g (yield: 59%) of the white solid intermediate I. 1 H NMR (500 MHz, CDCl3): δ (ppm) 8.61-8.59 (d, J = 8.9 Hz, 1H), 8.48-8.47 (d, J = 8.6 Hz, 1H), 7.78-7.77 (d, J = 7.4 Hz, 1H), 7.75-7.74 (d, J = 1.8 Hz, 1H), 7.68-8.65 (dd, J = 8.6, 1.8 Hz, 1H), 7.52-7.44 (m, 2H).

[0350] (2) Synthesis of intermediate J

[0351]

[0352] 0.6 g (0.0018 mol) of intermediate I, 0.36 g (0.0022 mol) of Carbazole, and K2CO3 were dissolved in 30 mL of toluene and stirred for 30 minutes under nitrogen conditions. 7.2 mg (2 mol%) of Tris(dibenzylideneacetone)dipalladium(0) (Pd2(dba)3) and 4.4 mg (4 mol%) of Tri-tert-butylphosphine were added to the reactor and stirred at 110 °C for 24 hours. The reactor was cooled to room temperature, the reaction solvent was removed, and the mixture was purified by column chromatography to obtain 0.26 g (yield: 35%) of intermediate J, a white solid. 1 H NMR (500 MHz, CDCl3): δ (ppm) 8.89-8.87 (d, J = 8.6 Hz, 1H), 8.69-8.68 (d, J = 7.0 Hz, 1H), 8.17-8.16 (d, J = 8.0 Hz, 2H), 7.86-7.81 (m, 3H), 7.58-7.57 (d, J = 8.3 Hz, 2H), 7.56-7.52 (td, J = 7.7, 1.4 Hz, 1H), 7.52-7.47 (m, 3H), 7.39-7.36 (t, J = 7.3 Hz, 2H).

[0353] (3) Synthesis of Compounds 2-5

[0354]

[0355] 0.39 g (0.93 mmol) of intermediate J was dissolved in 60 mL of THF under nitrogen conditions and cooled to -78°C. 3.75 mL of 1.0 M phenylmagnesium bromide was slowly added dropwise to the reaction solution. After stirring at room temperature for 6 hours, it was extracted with diethylether. After removing the solvent, the reaction mixture was dissolved in 10 mL of CH3COOH without further purification, and 2 mL of HCl was slowly added dropwise. After stirring at room temperature for 1 hour, it was neutralized with an aqueous solution of NaHCO3 and extracted with CH2Cl2. After removing the solvent, it was purified by column chromatography to obtain 0.2 g (yield: 40%) of the white solid compound 2-5. 1 H NMR (500 MHz, CDCl3): δ (ppm) 8.15-8.13 (d, J = 7.9 Hz, 2H), 7.74-7.72 (d, J = 7.6 Hz, 1H), 7.70-7.69 (d, J = 2.2 Hz, 1H), 7.49-7.42 (m, 7H), 7.40-7.37 (t, J = 7.6 Hz, 4H), 7.33-7.30 (t, J = 7.3 Hz, 2H), 7.21-7.18 (m, 2H), 7.00-6.99 (d, J = 7.7 Hz, 4H), 6.85-6.82 (t, J = 8.0 Hz, 1H), 5.53-5.51 (d, J = 8.3 Hz, 1H).

[0356] Synthesis Example 4: Synthesis of Compound 2-17

[0357] (1) Synthesis of intermediate K

[0358]

[0359] Using 0.6 g (0.0018 mol) of intermediate I and 0.73 g (0.0022 mol) of 9,9-diphenylacridine in the same manner as the synthesis method of intermediate J, 0.44 g (yield: 42%) of intermediate K, a white solid, was obtained.

[0360] (2) Synthesis of Compound 2-17

[0361]

[0362] 0.26 g (yield: 48%) of the white solid compound 2-17 was obtained using 0.44 g (0.75 mmol) of intermediate K and 3.0 mL of 1.0 M PhMgBr in the same manner as the synthesis of compound 3.

[0363] Experimental Example 1: Evaluation of Energy Levels of Organic Compounds

[0364] For Compounds 1-1, 1-2, 2-5, and 2-17 synthesized in Synthesis Examples 1 to 4, respectively, the HOMO energy level, LUMO energy level, band gap between these energy levels (Eg), excited singlet energy level (S1), excited triplet energy level (T1), and emission wavelength (PL peak) were measured. The results of the simulation evaluation are shown in Table 1 below, and the results of experiments on thin films coated in solution are shown in Table 2 below.

[0365] Energy level simulation of organic compounds (DFT calculation) compound HOMO(eV) LUMO(eV) Eg S1 (eV) T1(eV) 1-1 -5.53 -1.16 4.37 3.81 3.18 1-2 -5.23 -1.30 3.93 3.55 3.15 2-5 -5.49 -0.94 3.55 3.93 3.18 2-17 -5.17 -0.94 4.23 3.50 3.33

[0366] Measurement of energy levels of organic compounds compound PL(sol) a Eg optb Homosexual c (eV) LUMO d (eV) T1(eV) 1-1 355 3.4 -5.7 -2.3 3.0 1-2 376 3.3 -5.6 -2.3 3.0 2-5 347 3.5 -5.7 -2.2 3.0 2-17 388 3.2 -5.6 -2.4 2.9 a : 2-Me THF; b : Toluene; c Sample : 1 mM, DMF solution; d LUMO(eV) = HOMO(eV)+E g opt (eV)

[0367] As shown in Tables 1 and 2, the HOMO energy level, LUMO energy level, singlet energy level, and triplet energy level of compounds 1-1, 1-2, 2-5, and 2-17 synthesized in the synthesis examples were suitable for application to the emissive layer. The compounds synthesized in the synthesis examples had very high excited triplet energy levels, making them suitable for use as hosts for the emissive material layer, electron transport layers, and / or hole blocking layers. In addition, it was confirmed that the compounds synthesized in the synthesis examples emit light in the blue wavelength band.

[0368] Example 1: Manufacture of an Organic Light-Emitting Diode

[0369] An organic light-emitting diode was fabricated using Compound 1-1 as a host for the light-emitting layer. Before use, the ITO-attached substrate was cleaned with UV ozone and loaded into an evaporation system. It was transferred into a deposition chamber to deposit other layers on top of the substrate. Approximately 10 -7 An organic layer was deposited in the following order by evaporation from a heated boat under a Torr vacuum. At this time, the deposition rate of the organic material was set to 1 Å / s.

[0370] ITO (50 nm); hole injection layer (HAT-CN, thickness 7 nm), hole transport layer (TAPC, thickness 50 nm), electron blocking layer (DCDPA, thickness 10 nm), emitting material layer (compound 1-1 as host and 30 wt% doped with blue delayed fluorescent material TczTrz, thickness 30 nm), hole blocking layer (TSPO1, thickness 5 nm), electron transport layer (TPBi, thickness 25 nm), electron injection layer (LiF, thickness 1.5 nm), cathode (Al, thickness 100 nm).

[0371] After depositing the capping layer (CPL), it was encapsulated in glass. Following the deposition of these layers, they were transferred from the deposition chamber into a drying box for film formation, and subsequently encapsulated using UV-cured epoxy and a moisture getter.

[0372] Examples 2 to 3: Manufacturing of Organic Light-Emitting Diodes

[0373] An organic light-emitting diode was fabricated by repeating the procedure of Example 1, except that Compound 1-2 synthesized in Synthesis Example 2 (Example 2) and Compound 2-5 synthesized in Synthesis Example 3 (Example 3) were used, respectively, instead of Compound 1-1 as the host of the light-emitting material layer.

[0374] Comparative Example 1: Fabrication of Organic Light-Emitting Diode

[0375] An organic light-emitting diode was fabricated by repeating the procedure of Example 1, except that mCBP was used instead of Compound 1 as the host of the light-emitting material layer.

[0376] Experimental Example 2: Measurement of Luminescence Characteristics of Organic Light-Emitting Diodes

[0377] Optical characteristics were measured for the organic light-emitting diodes fabricated in Examples 1 to 3 and Comparative Example 1, respectively. Each organic light-emitting diode having an emission area of ​​9 mm² was connected to an external power source, and device characteristics were evaluated at room temperature using a current source (KEITHLEY) and a photometer (PR 650). At a current density of 10 mA / cm², the driving voltage (V), current efficiency (cd / A), power efficiency (lm / W), external quantum efficiency (EQE, %), and maximum external quantum efficiency (EQE) of each organic light-emitting diode were measured. max ) and CIE color coordinates were measured. The measurement results are shown in Table 3 below.

[0378] Luminescence characteristics of organic light-emitting diodes Sample Host V cd / A lm / W EQE EQE max CIE(x,y) Comparative Example 1 mCBP 4.0 25.8 20.4 14.7 22.8 (0.162, 0.289) Example 1 1-1 4.1 27.5 21.2 15.3 23.0 (0.163, 0.298) Example 2 1-2 4.2 27.0 19.5 15.0 23.8 (0.164, 0.299) Example 3 2-5 3.7 30.1 25.8 15.7 22.0 (0.170, 0.333)

[0379] As shown in Table 3, compared to the organic light-emitting diode of Comparative Example 1 using mCBP as a host, the driving voltage of the organic light-emitting diode of the example was equivalent or slightly lower, and the current efficiency, power efficiency, and external quantum efficiency were improved by up to 16.7%, 26.5%, and 6.8%, respectively.

[0380] Although the present invention has been described above based on exemplary embodiments and examples, the present invention is not limited to the technical concept described in the embodiments and examples. Rather, those skilled in the art to which the present invention pertains can easily devise various modifications and changes based on the aforementioned embodiments and examples. However, it is evident from the appended claims that all such modifications and changes fall within the scope of the present invention. Explanation of the symbols

[0381] 100, 800, 1000: Organic light-emitting display device 210, 310, 410, 510, 910, 1110: First electrode 220, 220A, 320, 420, 520, 920, 1120, 1120A: Emitting layer 230, 330, 430, 530, 930, 1130: Second electrode 240, 240A, 340, 440, 640, 740, 940, 1240, 1340, 1440, 1540, 1640, 1740: Luminescent material layer D, D1, D2, D3, D4, D5, D6, D7, D8: Organic light-emitting diode Tr: Thin-film transistor

Claims

Claim 1 An organic compound having the structure of Chemical Formula 1 below. [Chemical Formula 1] In Chemical Formula 1, R1 is a condensed heteroaromatic functional group selected from the group consisting of carbazoleyl moiety, acridinyl moiety, dihydroacridinyl moiety, and phenazinyl moiety, wherein the condensed heteroaromatic functional group is unsubstituted or C1-C 20 Alkyl group, C6-C 30 Aryl group and C3-C 30 It is substituted with a functional group selected from the group consisting of heteroaryls, and the condensed heteroaromatic functional group is not condensed; R2 and R3 are each independently light hydrogen, deuterium, tritium, and C1-C 20 Selected from the group consisting of alkyl groups, where a and b are integers greater than or equal to 2, and respectively R2 and R3 are identical or different; a and b are the number of substituents, where a is an integer from 0 to 3 and b is an integer from 0 to 4; X and Y are each CR4R5, and R4 and R5 are each independently light hydrogen, deuterium, tritium, C1~C 20 Alkyl groups, and C6~C 30 Selected from the group consisting of aryl groups; m and n are integers of 0 or 1, respectively, and m+n=1; Z is sulfur (S) or oxygen (O). Claim 2 In claim 1, the condensed heteroaromatic functional group constituting R1 is an organic compound selected from the group consisting of a non-condensed carbazoleyl moiety, a non-condensed acridinyl moiety, and a non-condensed dihydroacridinyl moiety. Claim 3 In claim 1, the condensed heteroaromatic functional group constituting R1 is not substituted, or C1-C 10 It is substituted with a functional group selected from the group consisting of alkyl groups, phenyl groups, and carbazole groups, and R4 and R5 are each independently light hydrogen, deuterium, tritium, C1-C 10 An organic compound substituted with a functional group selected from the group consisting of alkyl groups and phenyl groups. Claim 4 In claim 1, Z is an organic compound that is sulfur (S). Claim 5 In claim 1, the organic compound is an organic compound comprising any one of the organic compounds having the structure of Chemical Formula 2 below. [Chemical Formula 2] Claim 6 In claim 1, the organic compound is an organic compound comprising any one of the organic compounds having the structure of Chemical Formula 3 below. [Chemical Formula 3] Claim 7 An organic light-emitting diode comprising: a first electrode; a second electrode facing the first electrode; and at least one light-emitting layer located between the first and second electrodes, wherein the at least one light-emitting layer comprises an organic compound having the structure of the following Chemical Formula 1. [Chemical Formula 1] In Chemical Formula 1, R1 is a condensed heteroaromatic functional group selected from the group consisting of carbazoleyl moiety, acridinyl moiety, dihydroacridinyl moiety, and phenazinyl moiety, wherein the condensed heteroaromatic functional group is unsubstituted or C1-C 20 Alkyl group, C6-C 30 Aryl group and C3-C 30 It is substituted with a functional group selected from the group consisting of heteroaryls, and the condensed heteroaromatic functional group is not condensed; R2 and R3 are each independently light hydrogen, deuterium, tritium, and C1-C 20 Selected from the group consisting of alkyl groups, where a and b are integers greater than or equal to 2, and respectively R2 and R3 are identical or different; a and b are the number of substituents, where a is an integer from 0 to 3 and b is an integer from 0 to 4; X and Y are each CR4R5, and R4 and R5 are each independently light hydrogen, deuterium, tritium, C1~C 20 Alkyl groups, and C6~C 30 Selected from the group consisting of aryl groups; m and n are integers of 0 or 1, respectively, and m+n=1; Z is sulfur (S) or oxygen (O). Claim 8 In claim 7, the condensed heteroaromatic functional group constituting R1 is an organic light-emitting diode selected from the group consisting of a non-condensed carbazoleyl moiety, a non-condensed acridinyl moiety, and a non-condensed dihydroacridinyl moiety. Claim 9 In claim 7, the condensed heteroaromatic functional group constituting R1 is not substituted, or C1-C 10 It is substituted with a functional group selected from the group consisting of alkyl groups, phenyl groups, and carbazole groups, and R4 and R5 are each independently light hydrogen, deuterium, tritium, C1-C 10 An organic light-emitting diode substituted with a functional group selected from the group consisting of alkyl groups and phenyl groups. Claim 10 In claim 7, the at least one light-emitting layer comprises at least one electron transport layer located between the first and second electrodes, and the at least one electron transport layer comprises the organic compound, forming an organic light-emitting diode. Claim 11 In claim 7, the at least one light-emitting layer comprises at least one hole-blocking layer located between the first and second electrodes, and the at least one hole-blocking layer comprises the organic compound, forming an organic light-emitting diode. Claim 12 In claim 7, the at least one light-emitting layer comprises a first light-emitting material layer located between the first and second electrodes, and the first light-emitting material layer comprises the organic compound, forming an organic light-emitting diode. Claim 13 In claim 12, the first light-emitting material layer comprises a first compound and a second compound, wherein the excited triplet energy level of the first compound is higher than the excited triplet energy level of the second compound, and the first compound is an organic light-emitting diode comprising the organic compound. Claim 14 In claim 13, the first light-emitting material layer further comprises a third compound in an organic light-emitting diode. Claim 15 In claim 13, the organic light-emitting diode in which the excitation singlet energy level of the third compound is lower than the excitation singlet energy level of the second compound. Claim 16 An organic light-emitting diode according to claim 13, further comprising a second light-emitting material layer located between the first electrode and the first light-emitting material layer or between the first light-emitting material layer and the second electrode, wherein the second light-emitting material layer comprises a fourth compound and a fifth compound. Claim 17 In claim 16, the above-mentioned fourth compound is an organic light-emitting diode comprising the above-mentioned organic compound. Claim 18 An organic light-emitting diode according to claim 16, further comprising a third light-emitting material layer located opposite the second light-emitting material layer with respect to the first light-emitting material layer, wherein the third light-emitting material layer comprises a sixth compound and a seventh compound. Claim 19 In claim 18, at least one of the fourth compound and the sixth compound is an organic light-emitting diode comprising the organic compound. Claim 20 An organic light-emitting device comprising: a substrate; and an organic light-emitting diode positioned on the substrate and described in any one of claims 7 to 19. Claim 21 In claim 7, the organic compound is an organic light-emitting diode comprising any one of the organic compounds in Chemical Formula 2 below. [Chemical Formula 2] Claim 22 In claim 7, the organic compound is an organic light-emitting diode comprising any one of the organic compounds in Chemical Formula 3 below. [Chemical Formula 3]

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