Organic light-emitting diode and organic light-emitting device including the same

Abstract

The present invention relates to an organic light-emitting diode in which a light-emitting material layer located between two electrodes includes a first compound in which an electron donor moiety and an electron acceptor moiety form a carbon-carbon bond, and a second compound in which a boron atom and a nitrogen atom form a condensed ring, and an organic light-emitting device including the organic light-emitting diode. The first compound and the second compound may be included in the same light-emitting material layer, or may be included in adjacent light-emitting material layers. By adopting a light-emitting material layer including a first compound in which an electron donor moiety and an electron acceptor moiety form a carbon-carbon bond having high bond energy, and a second compound having an adjusted energy level compared to the first compound, the driving voltage of the organic light-emitting diode can be reduced and the luminous efficiency and luminous life can be improved.

Description

[Technical field]

[0001] This application claims the benefit of priority to Patent Application No. 10-2021-0180229, filed in Korea on December 16, 2021, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to an organic light emitting diode, and more particularly to an organic light emitting diode having excellent light emitting characteristics and an organic light emitting device including the same. [Background technology]

[0003] Organic light emitting diodes, a type of flat display device, are gaining attention as a light emitting device that can replace liquid crystal display devices. Organic light emitting diodes (OLEDs) are made of organic thin films of less than 2000 Å and can display images in one or both directions depending on the electrode configuration used. In addition, organic light emitting diodes can be formed on flexible transparent substrates such as plastic, making it easy to realize flexible or foldable display devices. Furthermore, organic light emitting diode display devices have many advantages over LCD devices, such as the ability to be driven at a low voltage and excellent color purity.

[0004] In an organic light-emitting diode, holes from the anode and electrons from the cathode combine in the light-emitting material layer to form excitons, which emit light when they return from an unstable excited state to a stable ground state. Conventional fluorescent materials have low luminous efficiency because only singlet excitons contribute to luminescence. Phosphorescent materials, in which triplet excitons also contribute to luminescence, have higher luminous efficiency than fluorescent materials. However, metal complex compounds, a typical example of phosphorescent materials, have a short luminous lifetime, which limits their use. Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide an organic light emitting diode capable of improving luminous efficiency, color purity and luminous life while reducing the driving voltage, and an organic light emitting device including the organic light emitting diode. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided an organic light-emitting diode including a first electrode, a second electrode facing the first electrode, and a light-emitting layer located between the first electrode and the second electrode and including at least one light-emitting material layer, the at least one light-emitting material layer including a first compound and a second compound, the first compound including an organic compound having a structure of the following chemical formula (1), and the second compound including an organic compound having a structure of the following chemical formula (7).

[0007] [ka]

[0008] In chemical formula (1), R 1 and R 2 are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, or a substituted or unsubstituted C1-C 20 Alkyl groups, substituted or unsubstituted C1-C 20 Alkylamino groups, substituted or unsubstituted C1-C 20 Alkylsilyl groups, substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 When a is plural, each R 1 may be the same or different, and when b is plural, each R 2 Optionally, when a and b are each plural, two adjacent R 1 , and / or two adjacent R 2 are bonded to each other, and are substituted or unsubstituted C6 to C20 or substituted or unsubstituted C3-C 20 D is a moiety having the structure of the following chemical formula (2) or the following chemical formula (3). R 1 and R 2 are each a hydrogen atom, a and b are each 4, and R 1 and R 2 are not hydrogen atoms, a and b are each independently an integer of 0 to 4.

[0009] [ka]

[0010] In chemical formula (2), R 3 is a substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 R is a heteroaromatic group. 4 and R 5 are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, or a substituted or unsubstituted C1-C 20 Alkyl groups, substituted or unsubstituted C1-C 20 Heteroalkyl groups of the formula: 20 Alkenyl groups, substituted or unsubstituted C2-C 20 Heteroalkenyl groups, substituted or unsubstituted C2-C 20 Alkynyl groups, substituted or unsubstituted C2-C 20 Heteroalkynyl groups, substituted or unsubstituted C1-C 20 Alkylsilyl groups, substituted or unsubstituted C1-C 20 Alkylamino groups, substituted or unsubstituted C1-C 20 Alkoxy groups, carboxyl groups, cyano groups, sulfanyl groups, phosphine groups, substituted or unsubstituted C3-C 20 Alicyclic groups, substituted or unsubstituted C3-C 20 Heteroalicyclic groups, substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30When m is a multiple number, each R 4 may be the same or different, and when n is a plurality of R 5 may be the same or different. Optionally, when m and n are each plural, two adjacent R 4 , and / or at least two adjacent R 5 are bonded to each other, and are substituted or unsubstituted C6 to C 20 or substituted or unsubstituted C3-C 20 A heteroaromatic ring of the formula X can be formed. 1 ~X 4 One of them is a heterocyclic compound containing boron and oxygen atoms represented by the chemical formula (1): ring and the remainder are each independently a carbon atom bonded to CR 4 Or a nitrogen atom. Y 1 represents a single bond, m is an integer from 0 to 3, n is an integer from 0 to 4, and the asterisk indicates the bonding site.

[0011] [ka]

[0012] In chemical formula (3), Y 2 is CR 6 Or N and R 6 is a hydrogen atom, deuterium, tritium, substituted or unsubstituted C1-C 20 The A ring and the B ring each independently have the structure shown in the following chemical formula (4). The asterisk indicates the binding site.

[0013] [ka]

[0014] In chemical formula (4), R 7 is deuterium, tritium, substituted or unsubstituted C1-C 20 Alkyl groups, substituted or unsubstituted C1-C 20 Alkylamino groups, substituted or unsubstituted C6-C30 or a substituted or unsubstituted C3-C 30 When p is plural, each R 7 may be the same or different. Optionally, when p is plural, two adjacent R 7 are bonded to each other, and are substituted or unsubstituted C6 to C 20 or substituted or unsubstituted C3-C 20 R 8 and R 9 are each independently a hydrogen atom, deuterium, tritium, or a substituted or unsubstituted C1-C 20 Alkyl groups, substituted or unsubstituted C1-C 20 Alkylamino groups, substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 or optionally, R 8 and R 9 are bonded to each other, and are substituted or unsubstituted C6 to C 20 or substituted or unsubstituted C3-C 20 The heteroaromatic ring can be formed as follows: p is an integer of 0 to 3.

[0015] [ka]

[0016] In chemical formula (7), R 21 ~R 24 are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, or a substituted or unsubstituted C1-C 20 Alkyl groups, substituted or unsubstituted C1-C 20 Alkylamino groups, substituted or unsubstituted C1-C 20 Alkylsilyl groups, substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 and optionally R 21 ~R 24Among these, two adjacent rings may be bonded to each other to form a substituted or unsubstituted fused ring having a boron atom and a nitrogen atom. 25 ~R 28 are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, or a substituted or unsubstituted C1-C 20 Alkyl groups, substituted or unsubstituted C1-C 20 Alkylamino groups, substituted or unsubstituted C1-C 20 Alkylsilyl groups, substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 When q is plural, each R 25 may be the same or different, and when r is plural, each R 26 may be the same or different. In addition, when s is plural, R 27 may be the same or different, and when t is plural, R 28 may be the same or different. q and s are each independently an integer of 0 to 5, r is an integer of 0 to 3, and t is an integer of 0 to 4.

[0017] For example, the highest occupied molecular orbital (HOMO) energy level of the first compound DF ) and the HOMO energy level of the second compound (HOMO FD ) can satisfy the following formula (I): │HOMO FD -HOMO DF │<0.3 eV…(I)

[0018] Optionally, the Lowest Unoccupied Molecular Orbital (LUMO) energy level of the first compound may be shallower than or the same as the LUMO energy level of the second compound.

[0019] For example, the energy band gap between the highest occupied molecular orbital (HOMO) energy level and the lowest unoccupied molecular orbital (LUMO) energy level of the first compound can be about -2.6 eV or more and about -3.1 eV or less.

[0020] For example, the energy band gap between the highest occupied molecular orbital (HOMO) energy level and the lowest unoccupied molecular orbital (LUMO) energy level of the first compound is about 2.6 eV or more, approx. 3.1 eV or less.

[0021] For example, R 1 and R 2 are each a hydrogen atom, and D in formula (1) may be a moiety having a structure represented by formula (5) below.

[0022] [ka]

[0023] In chemical formula (5), R 13 is a substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 R is a heteroaryl group of the formula: 14 and R 15 are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, or a substituted or unsubstituted C1-C 20 Alkyl groups, substituted or unsubstituted C1-C 20 Alkylamino groups, substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 When m is a multiple number, each R 14 may be the same or different, and when n is a plurality of R 15 may be the same or different. Optionally, when m and n are each plural, two adjacent R 14 , and / or at least two adjacent R 15are bonded to each other, and are substituted or unsubstituted C6 to C 20 or substituted or unsubstituted C3-C 20 m is an integer from 0 to 3, n is an integer from 0 to 4, and the asterisk indicates the bonding site.

[0024] The second compound may include an organic compound having a structure represented by any one of the following chemical formulas (8A) to (8C).

[0025] [ka] [ka] [ka]

[0026] In chemical formulas (8A) to (8C), R 21 , R 25 ~R 28 , R 31 ~R 34 are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, or a substituted or unsubstituted C1-C 20 Alkyl groups, substituted or unsubstituted C1-C 20 Alkylsilyl groups, substituted or unsubstituted C1-C 20 Alkylamino groups, substituted or unsubstituted C6-C 30 Aryl groups, substituted or unsubstituted C3-C 30 is a heteroaryl group of the formula:

[0027] In an exemplary aspect, the at least one luminescent material layer can include a single-layer luminescent material layer.

[0028] The single-layer light-emitting material layer may further include a third compound.

[0029] Optionally, the at least one luminescent material layer can include a first luminescent material layer positioned between the first electrode and the second electrode, and a second luminescent material layer positioned between the first electrode and the first luminescent material layer or between the second electrode and the first luminescent material layer, wherein the first luminescent material layer includes a first compound and the second luminescent material layer includes a second compound.

[0030] When the first compound and the second compound are contained in the first light emitting material layer and the second light emitting material layer, respectively, the first light emitting material layer may further contain a third compound, and the second light emitting material layer may further contain a fourth compound.

[0031] The excited triplet energy level of the third compound may be higher than the excited triplet energy level of the first compound, and the excited triplet energy level of the first compound may be higher than the excited triplet energy level of the second compound.

[0032] The excited singlet energy level of the third compound may be higher than the excited singlet energy level of the first compound, and the excited singlet energy level of the first compound may be higher than the excited singlet energy level of the second compound.

[0033] The excited singlet energy level of the fourth compound may be higher than the excited singlet energy level of the second compound.

[0034] When the first compound and the second compound are contained in separate light emitting material layers, the at least one light emitting material layer may further include a third light emitting material layer located on the opposite side of the second light emitting material layer with the first light emitting material layer interposed therebetween.

[0035] The third light-emitting material layer includes a fifth compound and a sixth compound, and the fifth compound may include an organic compound having the structure of Chemical Formula (7).

[0036] The light emitting layer may include a first light emitting portion located between the first electrode and the second electrode, a second light emitting portion located between the first light emitting portion and the second electrode, and a charge generating layer located between the first light emitting portion and the second light emitting portion, and at least one of the first light emitting portion and the second light emitting portion may include the at least one light emitting material layer.

[0037] For example, the first light emitting part may include the at least one light emitting material layer, and the second light emitting part may emit light of at least one color selected from the group consisting of red and green.

[0038] According to yet 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, including a substrate and the above-described organic light emitting diode. Effect of the Invention

[0039] The present invention proposes an organic light-emitting diode in which a first compound, in which an electron donor moiety and an electron acceptor moiety are bonded with a bond having strong binding energy, and a second compound, the energy level of which is adjusted, are contained in the same light-emitting material layer or in adjacent light-emitting material layers, and an organic light-emitting device including the organic light-emitting diode.

[0040] The first compound has a strong binding energy between the electron donor moiety and the electron acceptor moiety, so it can maintain a stable molecular structure even against the heat generated when the light-emitting device is driven. By adjusting the energy levels of the first compound and the second compound, holes are not captured by the second compound, and charges can be quickly injected and transferred to the first compound, which has excellent luminous efficiency and thermal stability. As a result, no exciton complex is formed between the first compound and the second compound, and 100% internal quantum efficiency is achieved in the first compound, which has excellent luminous efficiency, and excitons generated in the first compound are transferred to the second compound.

[0041] As a result, the charge injection efficiency and exciton generation efficiency are improved, the driving voltage of the organic light-emitting diode is reduced, and the light-emitting efficiency is greatly improved. In addition, the light emission is finally generated in the second compound, which has a narrow half-width and excellent emission lifetime, so the color purity and emission lifetime of the organic light-emitting diode can be improved. [Brief description of the drawings]

[0042] [Figure 1] 1 is a schematic circuit diagram of an organic light emitting display device according to an embodiment of the present invention; [Diagram 2] 1 is a cross-sectional view illustrating an example of an organic light-emitting display device according to an exemplary aspect of the present disclosure; [Diagram 3] 1 is a cross-sectional view illustrating an organic light-emitting diode according to an exemplary aspect of the present invention. [Figure 4] FIG. 1 is a schematic diagram illustrating a state in which the energy level of a light-emitting material is adjusted around a first compound and a second compound constituting a light-emitting material layer, and holes are efficiently transferred to the second compound, according to an exemplary aspect of the present invention. [Diagram 5] FIG. 1 is a schematic diagram illustrating the problem of holes being trapped by a first compound and a second compound constituting a light-emitting material layer when the HOMO energy levels of the second compound are not adjusted. [Figure 6] FIG. 1 is a schematic diagram showing a problem that occurs when the HOMO and LUMO energy levels of a first compound and a second compound constituting a light-emitting layer are not adjusted, resulting in the formation of an exciplex between the first compound and the second compound, as a result of holes being trapped in the second compound. [Figure 7] 1 is a schematic diagram illustrating a light emission mechanism based on singlet energy levels and triplet energy levels between light emitting materials in a light emitting material layer constituting an organic light emitting diode according to an exemplary aspect of the present invention. FIG. [Figure 8] 1 is a cross-sectional view illustrating an organic light-emitting diode according to another exemplary aspect of the present invention. [Figure 9]FIG. 1 is a schematic diagram illustrating a state in which the HOMO energy levels of a first compound and a second compound constituting an emissive layer are adjusted to allow efficient transfer of holes to the second compound, according to another exemplary aspect of the present invention. [Figure 10] FIG. 2 is a schematic diagram illustrating a light emission mechanism based on singlet energy levels and triplet energy levels between light emitting materials in a light emitting material layer constituting an organic light emitting diode according to another exemplary aspect of the present invention. [Figure 11] 1 is a cross-sectional view illustrating an organic light-emitting diode according to yet another exemplary aspect of the present invention. [Figure 12] FIG. 1 is a schematic diagram illustrating a state in which the HOMO energy levels of a first compound and a second compound constituting an emissive layer are adjusted to allow efficient transfer of holes to the second compound, according to yet another exemplary aspect of the present invention. [Figure 13] FIG. 13 is a schematic diagram illustrating a light emission mechanism based on singlet energy levels and triplet energy levels between light emitting materials in a light emitting material layer constituting an organic light emitting diode according to yet another exemplary aspect of the present invention. [Figure 14] 1 is a cross-sectional view illustrating an organic light-emitting diode according to yet another exemplary aspect of the present invention. [Figure 15] 1 is a cross-sectional view illustrating an example of an organic light-emitting display device according to yet another exemplary aspect of the present disclosure; [Figure 16] 1 is a cross-sectional view illustrating an organic light-emitting diode according to yet another exemplary aspect of the present invention. [Figure 17] 1 is a cross-sectional view illustrating an example of an organic light-emitting display device according to yet another exemplary aspect of the present disclosure; [Figure 18] 1 is a cross-sectional view illustrating an organic light-emitting diode according to another aspect of the present invention. [Figure 19] 1 is a cross-sectional view illustrating an organic light-emitting diode according to another aspect of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] The present invention relates to an organic light emitting diode in which a first compound in which an electron donor moiety and an electron acceptor moiety are bonded with strong binding energy and a second compound in which the energy level is adjusted compared to the first compound are used in the same light emitting material layer or an adjacent light emitting material layer, and an organic light emitting device including the organic light emitting diode. The organic light emitting diode according to the present invention can be used in an organic light emitting device such as an organic light emitting display device or an organic light emitting lighting device. As an example, a display device using the organic light emitting diode of the present invention will be described.

[0044] 1 is a schematic circuit diagram of an organic light emitting display device according to an exemplary aspect of the present invention. As shown in FIG. 1, an organic light emitting display device 100 is formed with gate lines GL, data lines DL, and power lines PL that cross each other to define a pixel region P. A switching thin film transistor Ts, a driving thin film transistor Td, a storage capacitor Cst, and an organic light emitting diode D are formed in the pixel region P. The pixel region P may include a first pixel region P1 (see FIG. 15), a second pixel region P2 (see FIG. 15), and a third pixel region P3 (see FIG. 15).

[0045] The switching thin film transistor Ts is connected to the gate line GL and the data line DL, and the driving thin film transistor Td and the storage capacitor Cst are connected between the switching thin film transistor Ts and the power line PL. The organic light emitting diode D is connected to the driving thin film transistor Td. In this organic light emitting display device, when the switching thin film transistor Ts is turned on by a gate signal applied to the gate line GL, the data signal applied to the data line DL is applied to the gate electrode 130 (FIG. 2) of the driving thin film transistor Td and one electrode of the storage capacitor Cst through the switching thin film transistor Ts.

[0046] The driving thin film transistor Td is turned on by a data signal applied to the gate electrode 130. As a result, a current proportional to the data signal flows from the power line PL to the organic light emitting diode D through the driving thin film transistor Td, and the organic light emitting diode D emits light with a brightness proportional to the current flowing through the driving thin film transistor Td. At this time, the storage capacitor Cst is charged to a voltage proportional to the data signal, so that the voltage of the gate electrode of the driving thin film transistor Td is kept constant during one frame. Therefore, the organic light emitting display device 100 can display a desired image.

[0047] 2 is a cross-sectional view showing an organic light-emitting display device according to an exemplary aspect of the present invention. As shown in FIG. 2, 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.

[0048] The substrate 110 may be a glass substrate, a thin flexible substrate, or a polymer plastic substrate. For example, the flexible substrate may be made of any one of polyimide (PI), polyethersulfone (PES), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), and polycarbonate (PC). The substrate 110 on which the thin film transistor Tr and the organic light emitting diode D are located constitutes an array substrate.

[0049] A buffer layer 122 is formed on the substrate 110, and a thin film transistor Tr is formed on the buffer layer 122. The buffer layer 122 may be omitted.

[0050] A semiconductor layer 120 is formed on top of the buffer layer 122. For example, the semiconductor layer 120 can be formed from an oxide semiconductor material. When the semiconductor layer 120 is made of an oxide semiconductor material, a light-shielding pattern (not shown) can be formed under the semiconductor layer 120. The light-shielding pattern prevents light from entering the semiconductor layer 120 and prevents the semiconductor layer 120 from deteriorating due to light. Optionally, the semiconductor layer 120 can also be formed from polycrystalline silicon, and in this case, impurities may be doped at both ends of the semiconductor layer 120.

[0051] On top of the semiconductor layer 120, a gate insulating film 124 made of an insulating material is formed on the entire surface of the substrate 110. The gate insulating film 124 can be formed from an inorganic insulating material such as silicon oxide (SiO x ), or silicon nitride (SiN x )(0 < X ≤ 2).

[0052] On top of the gate insulating film 124, a gate electrode 130 made of a conductive material such as metal is formed corresponding to the center of the semiconductor layer 120. In FIG. 2, the gate insulating film 124 is formed on the entire surface of the substrate 110, but the gate insulating film 124 may be patterned in the same shape as the gate electrode 130.

[0053] On top of the gate electrode 130, an interlayer insulating film 132 made of an insulating material is formed on the entire surface of the substrate 110. The interlayer insulating film 132 may be formed from an inorganic insulating material such as silicon oxide (SiO x ) or silicon nitride (SiN x ), or may be formed from an organic insulating material such as benzocyclobutene or photoacrylic.

[0054] The interlayer insulating film 132 has first and second semiconductor layer contact holes 134, 136 exposing both upper surfaces of the semiconductor layer 120. The first and second semiconductor layer contact holes 134, 136 are located on both sides of the gate electrode 130 and spaced apart from the gate electrode 130. Here, the first and second semiconductor layer contact holes 134, 136 can also be formed in the gate insulating film 124. When the gate insulating film 124 is patterned to have the same shape as the gate electrode 130, the first and second semiconductor layer contact holes 134, 136 are formed only in the interlayer insulating film 132.

[0055] A source electrode 144 and a drain electrode 146 made of a conductive material such as a metal are formed on the interlayer insulating film 132. The source electrode 144 and the drain electrode 146 are spaced apart with the gate electrode 130 interposed therebetween and contact both sides of the semiconductor layer 120 through first and second semiconductor layer contact holes 134 and 136, respectively.

[0056] The semiconductor layer 120, the gate electrode 130, the source electrode 144, and the drain electrode 146 constitute a thin film transistor Tr, which functions as a driving element. The thin film transistor Tr shown in FIG. 2 has a coplanar structure in which the gate electrode 130, the source electrode 144, and the drain electrode 146 are located on the upper part 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 lower part of the semiconductor layer, and the source electrode and the drain electrode are located on the upper part of the semiconductor layer. In this case, the semiconductor layer may be made of amorphous silicon.

[0057] Although not shown in FIG 2, the gate lines GL (see FIG 1) and the data lines DL (see FIG 1) cross each other to define a pixel region P (see FIG 1), and a switching element Ts (see FIG 1) connected to the gate lines GL and the data lines DL is further formed. The switching element Ts is connected to a thin film transistor Tr serving as a driving element. In addition, a power line PL (see FIG 1) is formed parallel to and spaced apart from the data line DL, and a storage capacitor Cst (see FIG 1) for maintaining a constant voltage of the gate electrode of the thin film transistor Tr serving as the driving element during one frame may be further formed.

[0058] A planarization layer 150 is formed on the entire surface of the substrate 110 above the source electrode 144 and the drain electrode 146. The planarization 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.

[0059] The organic light emitting diode D is located on the planarization layer 150 and includes a first electrode 210 connected to the drain electrode 146 of the thin film transistor Tr, a light emitting layer 220 and a second electrode 230 sequentially stacked on the first electrode 210.

[0060] The first electrode 210 is formed separately for each pixel region. The first electrode 210 may be an anode. The first electrode 210 may be made of a conductive material having a relatively large work function, for example, a transparent conductive oxide (TCO). In one exemplary aspect, when the organic light emitting display device 100 of the present invention is a bottom emission type, the first electrode 210 may have a single layer structure made of a transparent conductive oxide.

[0061] In another exemplary aspect, when the organic light emitting display device 100 of the present invention is a top emission type, a reflective electrode or a reflective layer may be further formed under 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 three-layer structure of ITO / Ag / ITO or ITO / APC / ITO. In addition, a bank layer 160 covering an end of the first electrode 210 is formed on the planarization layer 150. The bank layer 160 corresponds to a pixel region and exposes the center of the first electrode 210.

[0062] The light-emitting layer 220 is formed on the first electrode 210. In one exemplary aspect, the light-emitting layer 220 may have a single-layer structure of an emitting material layer (EML). Optionally, the light-emitting layer 220 may include a hole injection layer (HIL), a hole transport layer (HIL), and / or an electron blocking layer (EBL) sequentially stacked between the light-emitting material layer and the first electrode 210, and a hole blocking layer (HBL), an electron transport layer (ETL), and / or an electron injection layer (EIL) sequentially stacked between the light-emitting material layer and the second electrode 230 (see FIGS. 3, 8, 11, and 14). The light-emitting layer 220 may include one light-emitting portion, or two or more light-emitting portions may form a tandem structure.

[0063] A second electrode 230 is formed on the substrate 110 on which the light emitting layer 220 is formed. The second electrode 230 is located on the entire surface of the display area, and is made of a conductive material with a relatively small work function, and can be used as a cathode. When the organic light emitting display device 100 is a top emission type, the second electrode 230 has a thin thickness and is light transmissive (semi-transmissive) characteristic.

[0064] An encapsulation film 170 is formed on the second electrode 230 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.

[0065] The OLED display 100 may further include a polarizer to reduce reflection of external light. For example, the polarizer may be circular. If the OLED display 100 is a bottom emission type, the polarizer may be located under the substrate 110. Meanwhile, if the OLED display 100 is a top emission type, the polarizer may be located on the encapsulation film 170. In addition, in the top emission type OLED display 100, a cover window may be attached on the encapsulation film 170 or the polarizer. In this case, if the substrate 110 and the cover window are made of a flexible material, a flexible display device may be configured.

[0066] An organic light emitting diode applicable to the organic light emitting display device according to the first aspect of the present invention will be described in detail. Fig. 3 is a cross-sectional view showing an organic light emitting diode according to the first embodiment of the present invention. As shown in Fig. 3, 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 an emission layer 220 located between the first electrode 210 and the second electrode 230. The organic light emitting display device 100 (see Fig. 2) 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 the blue pixel region.

[0067] In an exemplary aspect, the light emitting layer 220 includes a light emitting material layer 240 (EML) located between the first electrode 210 and the second electrode 230. The light emitting layer 220 may also include at least one of a hole transport layer 260 (HTL) located between the first electrode 210 and the light emitting material layer 240, and an electron transport layer 270 (ETL) located between the light emitting material layer 240 and the second electrode 230. The light emitting layer 220 may further include at least one of a hole injection layer 250 (HIL) located between the first electrode 210 and the hole transport layer 260, and an electron injection layer 280 (EIL) located between the electron transport layer 270 and the second electrode 230. Optionally, organic light-emitting diode D1 may include an electron blocking layer 265 (EBL) located between the light-emitting material layer 240 and the hole transport layer 260, and / or a hole blocking layer 275 (HBL) located between the light-emitting material layer 240 and the electron transport layer 270.

[0068] The first electrode 210 may be an anode that supplies holes to the light emitting material layer 240. The first electrode 210 may be formed of a conductive material having a relatively large work function, for example, a transparent conductive oxide (TCO). As an example, the first electrode 210 may be made of, but is not limited to, 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).

[0069] The second electrode 230 may be a cathode that supplies electrons to the light emitting material layer 240. The second electrode 230 may be made of a conductive material having a relatively small work function, such as, but not limited to, aluminum (Al), magnesium (Mg), calcium (Ca), silver (Ag), or an alloy or combination thereof, and may be made of a material having good reflective properties.

[0070] The luminescent material layer 240 includes a first compound DF (see FIG. 4) and a second compound FD (see FIG. 4), and may optionally include a third compound H (see FIG. 4). For example, the first compound DF may be a delayed fluorescent material, the second compound FD may be a fluorescent material, and the third compound H may be a host.

[0071] When holes and electrons combine in the luminescent material layer 240 to form excitons, singlet excitons with paired spins and triplet excitons with unpaired spins are generated in a ratio of 1:3 due to the arrangement of spins. Conventional fluorescent materials have low luminous efficiency because only singlet excitons contribute to luminescence. On the other hand, phosphorescent materials have triplet excitons as well as singlet excitons that contribute to luminescence, but the luminescence lifetime is short and they are not yet at a level that can be used.

[0072] The first compound DF may be a delayed fluorescent material having thermally activated delayed fluorescence (TADF) properties. The delayed fluorescent material has an excited singlet energy level (S1 DF ) and excited triplet energy level (T1 DF ) energy band gap (ΔE ST ) is very narrow (see FIG. 7). Therefore, in the first compound DF, which can be a delayed fluorescent substance, the excited singlet energy level (S1 DF ) and the excited triplet energy level (T1 DF ) moves to a state where intramolecular charge transfer (ICT) is possible (S1→ICT←T1), and then transitions from there to the ground state (S0) (ICT→S0).

[0073] In order for energy transitions to occur in both the triplet and singlet states, the excited singlet energy level (S1 DF ) and excited triplet energy level (T1 DF ) energy band gap (ΔE ST, see Figure 7) must be 0.3 eV or less, for example 0.05 eV to 0.3 eV. Materials with a small energy difference between the singlet state and the triplet state not only exhibit fluorescence when the exciton energy of the original singlet state transitions to the ground state, but also exhibit delayed fluorescence as the singlet state transitions to the ground state, a phenomenon known as reverse intersystem crossing (RISC), in which the triplet state is up-converted by thermal energy at room temperature to a singlet state with a higher energy.

[0074] According to the present invention, the first compound DF contained in the light emitting material layer 240 has an electron donor moiety and an electron acceptor moiety that form a carbon-carbon bond with high bond energy. The electron acceptor moiety forms a fused ring containing a boron atom and an oxygen atom, and the electron donor moiety forms a polycyclic heteroaromatic ring having at least one nitrogen atom. The first compound DF having delayed fluorescence properties may have a structure represented by the following chemical formula (1).

[0075] [ka]

[0076] In chemical formula (1), R 1 and R 2 are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, or a substituted or unsubstituted C1-C 20 Alkyl groups, substituted or unsubstituted C1-C 20 Alkylamino groups, substituted or unsubstituted C1-C 20 Alkylsilyl groups, substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 When a is plural, each R 1 may be the same or different, and when b is plural, each R 2 Optionally, when a and b are each plural, two adjacent R1 , and / or two adjacent R 2 are bonded to each other, and are substituted or unsubstituted C6 to C 20 or substituted or unsubstituted C3-C 20 D is a moiety having the structure of the following chemical formula (2) or the following chemical formula (3). R 1 and R 2 are each a hydrogen atom, a and b are each 4, and R 1 and R 2 are not hydrogen atoms, a and b are each independently an integer of 0 to 4.

[0077] [ka]

[0078] In chemical formula (2), R 3 is a substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 R is a heteroaromatic group. 4 and R 5 are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, or a substituted or unsubstituted C1-C 20 Alkyl groups, substituted or unsubstituted C1-C 20 Heteroalkyl groups of the formula: 20 Alkenyl groups, substituted or unsubstituted C2-C 20 Heteroalkenyl groups, substituted or unsubstituted C2-C 20 Alkynyl groups, substituted or unsubstituted C2-C 20 Heteroalkynyl groups, substituted or unsubstituted C1-C 20 Alkylsilyl groups, substituted or unsubstituted C1-C 20 Alkylamino groups, substituted or unsubstituted C1-C 20 Alkoxy groups, carboxyl groups, cyano groups, sulfanyl groups, phosphine groups, substituted or unsubstituted C3-C 20 Alicyclic groups, substituted or unsubstituted C3-C 20Heteroalicyclic groups, substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 When m is a multiple number, each R 4 may be the same or different, and when n is a plurality of R 5 may be the same or different. Optionally, when m and n are each plural, two adjacent R 4 , and / or at least two adjacent R 5 are bonded to each other, and are substituted or unsubstituted C6 to C 20 or substituted or unsubstituted C3-C 20 A heteroaromatic ring of the formula X can be formed. 1 ~X 4 one of which is a carbon atom bonded to a heterocycle containing a boron atom and an oxygen atom of chemical formula (1), and the rest are each independently represented by CR 4 Or a nitrogen atom. Y 1 CR is a single bond 6 Or N and R 6 is a hydrogen atom, deuterium, tritium, substituted or unsubstituted C1-C 20 m is an integer from 0 to 3, n is an integer from 0 to 4, and the asterisk indicates the binding site.

[0079] [ka]

[0080] [ka]

[0081] In chemical formula (2), R 3 is a substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 R is a heteroaromatic group. 4 and R 5are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, or a substituted or unsubstituted C1-C 20 Alkyl groups, substituted or unsubstituted C1-C 20 Heteroalkyl groups of the formula: 20 Alkenyl groups, substituted or unsubstituted C2-C 20 Heteroalkenyl groups, substituted or unsubstituted C2-C 20 Alkynyl groups, substituted or unsubstituted C2-C 20 Heteroalkynyl groups, substituted or unsubstituted C1-C 20 Alkylsilyl groups, substituted or unsubstituted C1-C 20 Alkylamino groups, substituted or unsubstituted C1-C 20 Alkoxy groups, carboxyl groups, cyano groups, sulfanyl groups, phosphine groups, substituted or unsubstituted C3-C 20 Alicyclic groups, substituted or unsubstituted C3-C 20 Heteroalicyclic groups, substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 When m is a multiple number, each R 4 may be the same or different, and when n is a plurality of R 5 may be the same or different. Optionally, when m and n are each plural, two adjacent R 4 , and / or at least two adjacent R 5 are bonded to each other, and are substituted or unsubstituted C6 to C 20 or substituted or unsubstituted C3-C 20 A heteroaromatic ring of the formula X can be formed. 1 ~X 4 One of them is a heterocyclic compound containing boron and oxygen atoms represented by the chemical formula (1): ring and the remainder are each independently a carbon atom bonded to CR 4 Or a nitrogen atom. Y 1 represents a single bond, m is an integer from 0 to 3, n is an integer from 0 to 4, and the asterisk indicates the bonding site.

[0082] In chemical formula (4), R 7 is deuterium, tritium, substituted or unsubstituted C1-C 20 Alkyl groups, substituted or unsubstituted C1-C 20 Alkylamino groups, substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 When p is plural, each R 7 may be the same or different. Optionally, when p is plural, two adjacent R 7 are bonded to each other, and are substituted or unsubstituted C6 to C 20 or substituted or unsubstituted C3-C 20 R 8 and R 9 are each independently a hydrogen atom, deuterium, tritium, or a substituted or unsubstituted C1-C 20 Alkyl groups, substituted or unsubstituted C1-C 20 Alkylamino groups, substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 or optionally, R 8 and R 9 are bonded to each other, and are substituted or unsubstituted C6 to C 20 or substituted or unsubstituted C3-C 20 The heteroaromatic ring can be formed as follows: p is an integer of 0 to 3.

[0083] As used herein, "unsubstituted" means that a hydrogen atom is attached.

[0084] The term "substituted" as used herein refers to a C1-C alkyl group that is unsubstituted or substituted with at least one of deuterium, tritium, a hydroxyl group, a carbonyl group, and a halogen atom. 20 Alkyl groups of C1-C, unsubstituted or substituted with halogen atoms 20Alkoxy groups, halogen atoms, cyano groups, hydroxyl groups, carboxyl groups, carbonyl groups, amino groups, C1-C 20 Alkylamino groups, C6-C 30 Arylamino groups, C3-C 30 Heteroarylamino groups, C6-C 30 Aryl groups, C3-C 30 The substituents may include, but are not limited to, heteroaryl groups, nitro groups, hydrazyl groups, and sulfone groups.

[0085] In this specification, C1 to C 20 The chain aliphatic hydrocarbons are C1 to C 20 Alkanes, C2-C 20 Alkenes, C2-C 30 or an alkynyl group, alkenyl group, or alkynyl group obtained by removing one hydrogen atom from an alkyne, etc., of C1-C 20 These chain aliphatic hydrocarbons may be unsubstituted or substituted.

[0086] In this specification, an "alkyl group" refers to a linear or branched saturated hydrocarbon having 1 to 20 carbon atoms, and can include, but is not limited to, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a neopentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, and the like.

[0087] In this specification, an "alkenyl group" is a hydrocarbon group having 2 to 20 carbon atoms and at least one carbon-carbon double bond. In addition, in this specification, an "alkynyl group" is a hydrocarbon group having 2 to 20 carbon atoms and at least one carbon-carbon triple bond.

[0088] In the present specification, the term "alkoxy group" refers to a linear or branched alkyl group having an ether bond represented by -O(-alkyl). Examples of the alkyl group include, but are not limited to, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, a butoxy group, and a tert-butoxy group.

[0089] As used herein, "alicyclic" or "cycloalkyl" refers to a non-aromatic carbon-based ring having at least three carbon atoms, and can include, but is not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and norbornyl groups.

[0090] As used herein, the term "hetero" in "heteroaromatic" or "heteroalicyclic" refers to an aromatic ring or an alicyclic ring in which at least one carbon atom, for example, 1 to 5 carbon atoms, is substituted with at least one heteroatom selected from the group consisting of nitrogen (N), oxygen (O), sulfur (S), phosphorus (P), and combinations thereof.

[0091] As used herein, "aromatic" or "heteroaromatic" includes monocyclic aromatics / heteroaromatics or fused polycyclic aromatics / heteroaromatics having covalent bonds. For example, C6-C 30 The aromatic rings are C6 to C 30 Aryl groups of C7-C 30 Aralkyl groups, C6-C 30 Aryloxy groups, C6-C 30 Arylamino groups, C7-C 30 Aryl ester groups of C8 to C 30 The vinyl aryl groups may include, but are not limited to, the following vinyl aryl groups:

[0092] For example, C6~C 30 Aromatic groups of C6 to C 30The aryl group can be a fused or non-fused aryl group, such as, but not limited to, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, anthracenyl group, a pentalenyl group, an indenyl group, an indenoindenyl group, a heptalenyl group, a biphenylenyl group, an indacenyl group, a phenalenyl group, a phenanthrenyl group, a benzophenanthrenyl group, a dibenzophenanthrenyl group, an azulenyl group, a pyrenyl group, a fluoranthenyl group, a triphenylenyl group, a chrysenyl group, a tetraphenyl group, a tetracenyl group, a pleiadenyl group, a picenyl group, a pentaphenyl group, a pentacenyl group, a fluorenyl group, an indenofluorenyl group, or a spirofluorenyl group.

[0093] C3~C 30 The heteroaromatic group is C3-C 30 Heteroaryl groups of C4-C 30 Heteroaralkyl groups, C3-C 30 Heteroaryloxy groups, C3-C 30 Heteroarylamino groups, C4-C 30 Heteroaryl ester groups of C5-C 30 The heterovinylaryl groups may include, but are not limited to, the following heterovinylaryl groups:

[0094] For example, C3~C 30 or a heteroaromatic group of C3-C 30The heteroaryl group in the formula (I) is a pyrrolyl group, a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a tetrazinyl group, an imidazolyl group, a pyrazolyl group, an indolyl group, an isoindolyl group, an indazolyl group, an indolizinyl group, a pyrrolidinyl group, a carbazolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an indolocarbazolyl group, an indenocarbazolyl group, a benzyl group, a benzocarbazol ... a benzofurocarbazolyl group, a benzothienocarbazolyl group, a quinolinyl group, an isoquinolinyl group, a phthalazinyl group, a quinoxalinyl group, a cinnolinyl group, a quinazolinyl group, a quinozolinyl group, a quinolizinyl group, a purinyl group, a benzoquinolinyl group, a benzoisoquinolinyl group, a benzoquinazolinyl group, a benzoquinoxalinyl group, an acridinyl group, a phenanthrolinyl group, a perimidinyl group, a phenanthridine group, a The heteroaryl group may be, but is not limited to, a fused or non-fused heteroaryl group such as, for example, an nyl group, a pteridinyl group, a naphthalidinyl group, a furanyl group, a pyranyl group, an oxazinyl group, an oxazolyl group, an oxadiazolyl group, a triazolyl group, a dioxinyl group, a benzofuranyl group, a dibenzofuranyl group, a thiopyranyl group, a xanthenyl group, a chromenyl group, an isochromenyl group, a thioazinyl group, a thiophenyl group, a benzothiophenyl group, a dibenzothiophenyl group, a difuropyrazinyl group, a benzofurodibenzofuranyl group, a benzothienobenzothiophenyl group, a benzothienodibenzothiophenyl group, a benzothienobenzofuranyl group, a benzothienodibenzofuranyl group, or an N-substituted spirofluorenyl group, a spirofluorenoacridinyl group, a spirofluorenoxanthenyl group.

[0095] As used herein, "alkylamino," "alicyclic amino," "heteroalicyclic amino," "aromatic amino," and "heteroaromatic amino" refer to the groups represented by -NH(-alkyl) or -N(alkyl)2, -NH(-alicyclic) or -N(alicyclic)2, -NH(-heteroalicyclic) or -N(heteroalicyclic)2, -NH(-aromatic) or -N(aromatic)2, and -NH(-heteroaromatic) or -N(heteroaromatic)2, respectively.

[0096] For example, the alkylamino group represented by -NH(-alkyl) may include, but is not limited to, a methylamino group, an ethylamino group, a propylamino group, an isopropylamino group, a butylamino group, an isobutylamino group, a (sec-butyl)amino group, a (tert-butyl)amino group, a pentylamino group, an isopentylamino group, a (tert-pentyl)amino group, a hexylamino group, etc. Also, the alkylamino group represented by -N(alkyl)2 may include, but is not limited to, a dimethylamino group, a diethylamino group, a dipropylamino group, a diisopropylamino group, a dibutylamino group, a diisobutylamino group, a di(sec-butyl)amino group, a di(tert-butyl)amino group, a dipentylamino group, a diisopentylamino group, a di(tert-pentyl)amino group, a dihexylamino group, a N-ethyl-N-methylamino group, a N-methyl-N-propylamino group, a N-ethyl-N-propylamino group, etc.

[0097] On the other hand, in chemical formula (2), the two adjacent R 4 and two adjacent R 5 In the chemical formula (4), two adjacent R 7 , and R 8 and R 9 can be bonded to each other to form C6 to C 20 Aromatic rings, and C3-C 20 The heteroaromatic ring of is not particularly limited. For example, two adjacent R 4 and two adjacent R 5 In the chemical formula (4), two adjacent R 7 , and R 8 and R 9 can be bonded to each other to form C6 to C 20 Aromatic rings, and C3-C 20The heteroaromatic rings can include benzene rings, naphthyl rings, anthracene rings, phenanthrene rings, indene rings, fluorene rings, pyridine rings, pyrimidine rings, triazine rings, quinoline rings, indole rings, benzofuran rings, benzothiophene rings, dibenzofuran rings, dibenzothiophene rings, and combinations thereof, each of which can be unsubstituted or substituted.

[0098] In an exemplary aspect, in formula (2), two adjacent R 4 and two adjacent R 5 In the chemical formula (4), two adjacent R 7 , and R 8 and R 9 can be bonded to each other to form C6 to C 20 Aromatic rings, and C3-C 20 The heteroaromatic ring of R can be unsubstituted or substituted, for example, a heteroaromatic ring in which two or more rings are fused together. For example, two adjacent R 4 and two adjacent R 5 In the chemical formula (4), two adjacent R 7 , and R 8 and R 9 can be combined to form C3 to C 20 The heteroaromatic rings in can include, but are not limited to, indole rings, benzofuran rings, benzothiophene rings, and combinations thereof, each of which can be unsubstituted or substituted.

[0099] For example, heteroaromatic moieties having the structure of formula (2) or (3) that act as electron donors can include, but are not limited to, unsubstituted or substituted indenocarbazolyl moieties, indolocarbazolyl moieties, benzofurocarbazolyl moieties, and / or benzothienocarbazolyl moieties, respectively.

[0100] For example, in the chemical formulas (1) to (4), R1 ~R 9 C3 to C4 each of which can be formed by combining 20 Alicyclic groups, C3-C 20 Heteroalicyclic groups, C6-C 30 Aromatic groups, C3-C 30 Heteroaromatic groups, C6-C 30 Aromatic rings, and C3-C 30 The fused heteroaromatic rings are each independently unsubstituted or C1-C 20 Alkyl groups, for example C1-C 10 Alkyl groups (e.g., C1-C5 alkyl groups such as t-butyl), C6-C 30 Aryl groups (e.g., C6-C such as phenyl groups) 15 Aryl groups of C3-C 30 Heteroaryl groups (e.g., C3-C such as pyridyl) 15 Heteroaryl groups of C6-C 30 Arylamino groups, for example C6-C 20 and arylamino groups (eg, diphenylamino groups).

[0101] In chemical formula (1), the fused ring containing a boron atom and an oxygen atom acts as an electron acceptor moiety, and the fused heteroaromatic ring having at least one nitrogen atom and having the structure of chemical formula (2) or chemical formula (3) acts as an electron donor moiety. Therefore, the organic compound having the structure of chemical formula (1) has delayed fluorescence properties.

[0102] The electron donor moiety and the electron acceptor moiety form a carbon-carbon bond with strong bond energy, and have excellent thermal stability. Therefore, even while the first compound DF emits light, the electron donor moiety and the electron acceptor moiety that have formed a carbon-carbon bond with high dissociation energy can maintain a stable molecular structure. Furthermore, the stable carbon-carbon bond restricts the rotation of the electron donor moiety and the electron acceptor moiety, and a large steric hindrance occurs between them.

[0103] Therefore, the first compound DF having the structure of chemical formula (1) can rapidly transition (up-convert) triplet excitons to singlet excitons through reverse intersystem crossing (RISC). The first compound DF having delayed fluorescence properties has excellent luminescence efficiency, and when used in combination with the second compound FD in particular, the exciton energy is rapidly transferred from the first compound DF to the second compound FD, realizing superfluorescence with greatly improved luminescence properties.

[0104] In an exemplary aspect, R of formula (1) 1 and R 2 are hydrogen atoms, and X in chemical formula (2) 1 ~X 4 one of which is a carbon atom bonded to a heterocycle containing a boron atom and an oxygen atom of chemical formula (1), and the rest are each independently represented by CR 4 It could be.

[0105] For example, R in formula (1) 1 and R 2 are each a hydrogen atom, and D in formula (1) may be a moiety having the structure of formula (5) below.

[0106] [ka]

[0107] In chemical formula (5), R 13 is a substituted or unsubstituted C6-C 30or a substituted or unsubstituted C3-C 30 R is a heteroaryl group of the formula: 14 and R 15 are each independently deuterium, tritium, a halogen atom, or a substituted or unsubstituted C1-C 20 Alkyl groups, substituted or unsubstituted C1-C 20 Alkylamino groups, substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 When m is a multiple number, each R 14 may be the same or different, and when n is a plurality of R 15 may be the same or different. Optionally, when m and n are each plural, two adjacent R 14 , and / or at least two adjacent R 15 are bonded to each other, and are substituted or unsubstituted C6 to C 20 or substituted or unsubstituted C3-C 20 m is an integer from 0 to 3, n is an integer from 0 to 4, and the asterisk indicates the bonding site.

[0108] For example, in the chemical formula (5), R 13 ~R 15 C6 to C 30 Aryl groups, C3-C 30 Heteroaryl groups of C6-C 20 Aromatic rings, and C3-C 20 Each heteroaromatic ring may be independently unsubstituted and is a C1-C 20 Alkyl groups of C6 to C 30 Aryl groups, C3-C 30 Heteroaryl groups of C6-C 30 Arylamino groups, and C3-C 30 and heteroarylamino groups,

[0109] When the electron donor moiety of the first compound DF has the structure of chemical formula (5), it contains a five-membered ring, and the thermal stability of the first compound DF can be further improved. For example, the first compound DF having the structures of chemical formulas (1) to (5) can include, but is not limited to, any one selected from organic compounds (1-1) to (1-18) having the structure of the following chemical formula (6).

[0110] [ka] [ka]

[0111] The first compound DF, which may be a delayed fluorescent substance, has an excited singlet energy level (S1 DF ) and excited triplet energy level (T1 DF ) difference (ΔE ST ) is very small (0.3 eV or less, see FIG. 7), and the triplet exciton energy of the first compound DF is converted to singlet exciton energy by reverse intersystem crossing (RISC), resulting in good quantum efficiency.

[0112] However, the first compound DF having the structures of chemical formulas (1) to (6) has a twisted structure due to the bond structure of the electron donor-electron acceptor. In addition, the first compound DF uses triplet excitons, which causes a further charge transfer transition (CT transition). Due to the emission characteristics resulting from the CT emission mechanism, the first compound DF having the structures of chemical formulas (1) to (6) has a wide full width at half maximum (FWHM), and is limited in terms of color purity.

[0113] In addition, the excited singlet energy level of the first compound DF (S1 DF Some of the excitons in the excited triplet energy level (T1DF1 ) in the first compound DF, which then undergoes reverse intersystem crossing (RISC) to reach the excited triplet energy level (T1 DF ) to the excited singlet energy level (S1 DF ) and cannot transition to the excited triplet energy level (T1 DF ) are generated. Such triplet excitons interact with surrounding triplet excitons or polarons and are quenched by triplet-triplet annihilation (TTA) or triplet-polaron annihilation (TPA). That is, when the light-emitting material layer 240 contains only the first compound DF, the triplet exciton energy of the first compound DF cannot contribute to light emission. Furthermore, the quenching process such as TTA and TPA may reduce the light-emitting lifetime of the organic light-emitting diode.

[0114] In order to maximize the luminescence characteristics of the first compound DF, which is a delayed fluorescent material, the luminescent material layer 240 includes the second compound FD, which may be a fluorescent material, to realize hyperfluorescence. As described above, the first compound DF, which is a delayed fluorescent material, can utilize singlet exciton energy and triplet exciton energy. Therefore, when the luminescent material layer 240 includes a fluorescent material having an appropriate energy level in the second compound FD compared to the first compound DF, which is a delayed fluorescent material, the second compound FD absorbs the exciton energy emitted from the first compound DF, and the energy absorbed by the second compound FD generates only singlet excitons with 100% probability, thereby maximizing the luminescence efficiency.

[0115] The singlet exciton energy of the first compound DF, which is a delayed fluorescent material contained in the luminescent material layer 240, including the singlet exciton energy up-converted from the triplet exciton energy of the first compound DF and the original singlet exciton energy, is transferred to the second compound FD, which is a fluorescent material in the same luminescent material layer, by the mechanism of Forster Resonance Energy Transfer (FRET), and the final emission occurs in the second compound FD. In order to efficiently transfer the exciton energy generated in the first compound DF to the second compound FD, a compound having a large overlapping portion of the absorption wavelength band with the emission wavelength band of the first compound DF can be used as the second compound FD. The second compound FD that finally emits light has a narrow half-width, thereby improving color purity, and has an excellent emission life, thereby improving the life of the light-emitting device.

[0116] The second compound FD included in the luminescent material layer 240 may be a fluorescent material that emits blue light. For example, the second compound FD included in the luminescent material layer 240 may be a boron-based fluorescent material having a full width at half maximum (FWHM) of 35 nm or less. As an example, the second compound FD, which is a boron-based fluorescent material, may have a structure represented by the following chemical formula (7).

[0117] [ka]

[0118] In chemical formula (7), R 21 ~R 24 are each independently hydrogen, deuterium, tritium, a halogen atom, or a substituted or unsubstituted C1-C 20 Alkyl groups, substituted or unsubstituted C1-C 20 Alkylamino groups, substituted or unsubstituted C1-C 20 Alkylsilyl groups, substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 and optionally R 21 ~R 24Among these, two adjacent rings may be bonded to each other to form a substituted or unsubstituted fused ring having boron and nitrogen. 25 ~R 28 are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, or a substituted or unsubstituted C1-C 20 Alkyl groups, substituted or unsubstituted C1-C 20 Alkylamino groups, substituted or unsubstituted C1-C 20 Alkylsilyl groups, substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 When q is plural, each R 25 may be the same or different, and when r is plural, each R 26 may be the same or different. In addition, when s is plural, R 27 may be the same or different, and when t is plural, R 28 may be the same or different. q and s are each independently an integer of 0 to 5, r is an integer of 0 to 3, and t is an integer of 0 to 4.

[0119] For example, in the chemical formula (7), R 21 ~R 28 Each of these consists of C6~C 30 Aromatic groups and C3-C 30 Each heteroaromatic group may be independently unsubstituted and may be substituted with deuterium, tritium, C1-C 20 Alkyl groups of C6 to C 30 Aryl groups, C3-C 30 Heteroaryl groups of C6-C 30 Arylamino groups, and C3-C 30 and heteroarylamino groups,

[0120] As in the chemical formulas (1) to (4), in the chemical formula (7), R 21 ~R 28 C6 to C 30 The aromatic group is C6-C30 Aryl groups of C7-C 30 Aralkyl groups, C6-C 30 Aryloxy groups of C6 to C 30 In addition, in the chemical formula (7), R 21 ~R 28 C3 to C 30 Heteroaromatics are C3-C 30 Heteroaryl groups of C4-C 30 Heteroaralkyl groups, C3-C 30 Heteroaryloxy groups of C3-C 30 The heteroarylamino groups may include, but are not limited to, the following heteroarylamino groups:

[0121] The boron-based compound having the structure of chemical formula (7) has excellent luminescence properties. Since the boron-based compound having the structure of chemical formula (7) has a wide plate-like structure, it can efficiently receive exciton energy transfer from the first compound DF, thereby maximizing the luminescence efficiency.

[0122] In an exemplary aspect, R of formula (7) 21 ~R 24 R in formula (7) may not be bonded to each other. 22 and R 23 can be bonded to each other to form a condensed ring having a boron atom and a nitrogen atom. For example, the second compound FD can include boron-based organic compounds having structures of the following chemical formulas (8A) to (8C).

[0123] [ka] [ka] [ka]

[0124] In chemical formulas (8A) to (8C), R 21 , R25 ~R 28 , R 31 ~R 34 are each independently hydrogen, deuterium, tritium, a halogen atom, or a substituted or unsubstituted C1-C 20 Alkyl groups, substituted or unsubstituted C1-C 20 Alkylsilyl groups, substituted or unsubstituted C1-C 20 Alkylamino groups, substituted or unsubstituted C6-C 30 or a substituted or unsubstituted C3-C 30 is a heteroaryl group of the formula:

[0125] In chemical formulas (8A) to (8C), R 21 , R 25 ~R 28 and R 31 ~R 34 C6 to C 30 Aryl groups and C3-C 30 Each heteroaryl group may be independently unsubstituted and may be substituted with deuterium, tritium, C1-C 20 Alkyl groups of C6 to C 30 Aryl groups, C3-C 30 Heteroaryl groups of C6-C 30 Arylamino groups, and C3-C 30 and heteroarylamino groups,

[0126] In another exemplary aspect, the second compound FD, which is a boron-based organic compound, may include, but is not limited to, any one selected from organic compounds (2-1) to (2-33) having a structure represented by the following chemical formula (9):

[0127] [ka] [ka] [ka] [ka]

[0128] On the other hand, the third compound H that may be included in the light emitting material layer 240 has an energy band gap (E g If the emissive layer 240 includes a third compound H, which may be a host, the first compound DF may be a first dopant and the second compound FD may be a second dopant.

[0129] In an exemplary aspect, the third compound H that may be included in the luminescent material layer 240 is 4,4'-bis(N-carbazolyl)-1,1'-biphenyl; CBP, 3,3'-bis(N-carbazolyl)-1,1'-biphenyl; mCBP, 1,3-bis(carbazol-9-yl)benzene; mCP, 9-(3-(9H-carbazol-9-yl)phenyl)-9H-carbazole-3-carbonitrile; mCP-CN, oxybis(2,1-phenylene)bis (diphenylphosphine oxide); DPEPO, 2,8-bis(diphenylphosphoryl)dibenzothiophene; PPT, 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene; TmPyPB, 2,6-di(9H-carbazol-9-yl)pyridine; PYD-2Cz, 2,8-di(9H-carbazol-9-yl)dibenzothiophene; DCzDBT, 3',5'-di(carbazol-9-yl)-[1,1'-biphenyl]-3 ,5-dicarbonitrile;DCzTPA, 4'-(9H-carbazol-9-yl)biphenyl-3,5-dicarbonitrile;pCzB-2CN, 3'-(9H-carbazol-9-yl)biphenyl-3,5-dicarbonitrile;mCzB-2CN, diphenyl-4-triphenylsilylphenyl-phosphine oxide;TPS01, 9-(9-phenyl-9H-carbazol-6-yl)-9H-carbazole;CCP, 4-(3-(triphenylsilyl)phenyl)-4-phenyl-2-phenyl-1,1-di ... The aryl groups may include, but are not limited to, 9-(4-(9H-carbazol-9-yl)phenyl)-9H-3,9'-bicarbazole, 9-(3-(9H-carbazol-9-yl)phenyl)-9H-3,9'-bicarbazole, 9-(6-(9H-carbazol-9-yl)pyridin-3-yl)-9H-3,9'-bicarbazole, and combinations thereof.

[0130] In an exemplary aspect, when the light emitting material layer 240 (EML) includes a first compound DF, a second compound FD, and a third compound H, the content of the third compound H in the light emitting material layer 240 may be greater than the content of the first compound DF, and the content of the first compound DF may be greater than the content of the second compound FD. When the content of the first compound DF is greater than the content of the second compound FD, the exciton energy can be sufficiently transferred from the first compound DF to the second compound FD by the FRET mechanism. As an example, the light emitting material layer 240 (EML) may include the third compound H at about 55% by weight to about 85% by weight, the first compound DF at about 10% by weight to about 40% by weight, for example, about 10% by weight to about 30% by weight, and the second compound FD at about 0.1% by weight to about 5% by weight, for example, about 0.1% by weight to about 2% by weight, but is not limited thereto.

[0131] In an exemplary aspect, the HOMO energy level and / or LUMO energy level of the third compound H as a host, the first compound DF as a delayed fluorescent material, and the second compound FD as a fluorescent material must be appropriately adjusted. For example, to achieve superfluorescence, the host must induce the triplet state exciton in the delayed fluorescent material to contribute to light emission without quenching (non-radiative annihilation, quenching). Therefore, it is necessary to adjust the energy levels of the third compound H as a host, the first compound DF as a delayed fluorescent material, and the second compound FD as a fluorescent material.

[0132] FIG. 4 is a schematic diagram illustrating a state in which the energy level of the luminescent material is adjusted, mainly by the first compound and the second compound constituting the luminescent material layer, in an organic light-emitting diode D1 according to the first embodiment of the present invention, and charges are efficiently transferred.

[0133] As shown in FIG. 4, the HOMO energy level (HOMO H ) is the HOMO energy level (HOMO DF ) deeper than the LUMO energy level of the third compound H (LUMO H) is the LUMO energy level of the first compound DF (LUMO DF ) of the third compound H. In other words, the HOMO energy level (HOMO H ) and LUMO energy levels (LUMO H ) is the energy band gap between the HOMO energy level of the first compound DF (HOMO DF ) and LUMO energy levels (LUMO DF ) may be wider than the energy band gap between the

[0134] As an example, in the light-emitting layer (EML), the HOMO energy level (HOMO H ) and the HOMO energy level (HOMO DF ) difference (│HOMO H -HOMO DF │), or the LUMO energy level of the third compound H (LUMO H ) and the LUMO energy level of the first compound DF (LUMO DF ) difference (│LUMO H -LUMO DF |) may be about 0.5 eV or less, for example, about 0.1 eV to about 0.5 eV. In this case, the efficiency of charge transfer and / or charge injection from the third compound H to the first compound DF is improved, and the luminous efficiency of the organic light-emitting diode D1 can be improved.

[0135] In an exemplary aspect, the HOMO energy level of the first compound DF (HOMO DF ) and the HOMO energy level of the second compound FD (HOMO FD ) satisfies the following formula (I): │HOMO FD -HOMO DF │<0.3 eV…(I)

[0136] The HOMO energy level of the first compound DF (HOMO DF ) and the HOMO energy level of the second compound FD (HOMOFD ) satisfies formula (I), the holes injected into the light-emitting material layer 240 can be rapidly transferred to the first compound DF. As a result, the first compound DF can utilize all of its original singlet exciton energy and the singlet exciton energy transferred from the triplet exciton energy by the reverse intersystem crossing (RISC) mechanism, thereby achieving 100% internal quantum efficiency, and the exciton energy can be efficiently transferred to the second compound FD. For example, when the HOMO energy level (HOMO DF ) and the HOMO energy level of the second compound FD (HOMO FD ) can satisfy the following formula (II), but is not limited thereto. │HOMO FD -HOMO DF │≦0.2 eV…(II)

[0137] In another exemplary aspect, the LUMO energy level of the first compound DF (LUMO DF ) is the LUMO energy level of the second compound FD (LUMO FD ) of the first compound DF, it may be shallower than or equal to the LUMO energy level (LUMO DF ) and the LUMO energy level of the second compound FD (LUMO FD ) can satisfy the following formula (III). 0≦LUMO DF -LUMO FD ≦0.3 eV…(III)

[0138] The LUMO energy level of the first compound DF (LUMO DF ) and the LUMO energy level of the second compound FD (LUMO FD ) satisfies formula (III), the electrons injected into the light-emitting material layer 240 can be quickly transferred to the first compound DF. For example, when the LUMO energy level (LUMO DF ) and the LUMO energy level of the second compound FD (LUMO FD ) can satisfy the following formula (IV). 0≦LUMO DF -LUMO FD ≦0.2 eV…(IV)

[0139] Recombination of excitons can occur in the first compound DF, which is a delayed fluorescent material. Therefore, 100% internal quantum efficiency can be achieved via the reverse intersystem crossing (RISC) mechanism. The singlet exciton energy generated in the first compound DF via reverse intersystem crossing (RISC) can be transferred to the second compound FD, which is a fluorescent material, via FRET, and efficient emission can occur in the second compound FD.

[0140] For example, the HOMO energy level of the first compound DF (HOMO DF ) is about -5.4 eV to about -5.7 eV, and the LUMO energy level of the first compound DF (LUMO DF The HOMO energy level (HOMO) of the second compound FD may be, but is not limited to, about -2.7 eV to about -3.0 eV. FD ) is about -5.3 eV to about -5.7 eV, and the LUMO energy level of the second compound FD (LUMO FD ) can be about -2.7 eV to about -3.0 eV, but is not limited thereto.

[0141] The HOMO energy level of the first compound DF (HOMO DF ) and LUMO energy levels (LUMO DF ) is the energy band gap between the HOMO energy level of the second compound FD (HOMO FD ) and LUMO energy levels (LUMO FD In an exemplary aspect, the HOMO energy level of the first compound DF (HOMO DF ) and LUMO energy levels (LUMO DF The energy band gap between the first compound FD and the second compound FD can be about 2.6 eV or more and about 3.1 eV or less, for example, about 2.7 eV or more and about 3.0 eV or less. FD ) and LUMO energy levels (LUMOFD The band gap of the first compound DF may be about 2.4 eV or more and about 2.9 eV or less, for example, about 2.5 eV or more and about 2.8 eV or less. In this case, the exciton energy generated in the first compound DF may be efficiently transferred to the second compound FD, and sufficient light emission may occur in the second compound FD.

[0142] FIG. 5 is a schematic diagram showing the problem of holes being trapped in the second compound when the HOMO energy levels of the first and second compounds constituting the light-emitting layer are not adjusted. As shown in FIG. 5, the HOMO energy level (HOMO DF ) and the HOMO energy level of the second compound FD (HOMO FD ) is 0.3 eV or more, the holes injected into the light emitting material layer 240 are trapped in the second compound FD, which is a fluorescent material. That is, the holes injected into the light emitting material layer 240 do not move from the third compound H, which is a host, to the first compound DF, which is a delayed fluorescent material. Excitons are not formed in the first compound DF, which has excellent luminous efficiency, and the holes trapped in the second compound FD are directly recombined to form excitons and emit light. The triplet exciton energy of the first compound DF cannot contribute to luminescence and is annihilated non-luminescently, resulting in a decrease in luminous efficiency.

[0143] FIG. 6 is a schematic diagram showing the problem that, when the HOMO energy level and LUMO energy level of the first compound and the second compound constituting the light-emitting material layer are not adjusted, a hole is trapped in the second compound and an exciton complex is formed between the first compound and the second compound. As shown in FIG. 6, the HOMO energy level (HOMO DF ) and the HOMO energy level of the second compound FD (HOMO FD ) is 0.5 eV or more, the holes injected into the light emitting material layer 240 are trapped in the second compound FD which is a fluorescent material.

[0144] In addition, the LUMO energy level of the first compound DF (LUMODF ) is the LUMO energy level of the second compound FD (LUMO FD ) deeper (i.e., LUMO FD -LUMO DF >0), the hole trapped in the second compound FD and the electron transferred to the first compound DF form an exciton complex. The triplet exciton energy of the first compound DF is annihilated non-radiatively, the luminous efficiency decreases, and the band gap between the LUMO energy level and the HOMO energy level forming the exciton complex becomes very narrow, so light in the long wavelength band is emitted. Since the first compound DF and the second compound FD emit light simultaneously, the half width becomes wide and the color purity decreases.

[0145] Next, the light emitting mechanism in the light emitting material layer 240 according to the first embodiment of the present invention will be described. FIG. 7 is a schematic diagram showing the light emitting mechanism based on the singlet energy level and triplet energy level between light emitting materials in the light emitting material layer constituting the organic light emitting diode according to the first embodiment of the present invention. As shown in FIG. 7, the excited triplet energy level (T1 H ) and excited singlet energy level (S1 H ) are the excited triplet energy levels (T1 DF ) and excited singlet energy level (S1 DF ) higher than the excited triplet energy level (T1 H ) is the excited triplet energy level (T1 DF ) by about 0.2 eV or more, for example, by about 0.3 eV or more, or by about 0.5 eV or more.

[0146] The excited triplet energy level (T1 H ) and excited singlet energy level (S1 H ) is the excited triplet energy level (T1 DF ) and excited singlet energy level (S1 DF), the excited triplet energy level (T1 DF ) to the excited triplet energy level (T1 H ) undergoes reverse charge transfer. As a result, the triplet excitons are annihilated non-radiatively in the third compound H, which cannot emit triplet excitons, and the triplet excitons of the first compound DF, which has delayed fluorescence properties, cannot contribute to emission. DF ) and excited triplet energy level (T1 DF ) difference (ΔE ST ) can be about 0.3 eV or less, for example, about 0.05 eV to 0.3 eV.

[0147] In addition, in the light emitting material layer 240 (EML), it is necessary to realize an organic light emitting diode D1 having high efficiency and high color purity by efficiently transferring exciton energy from the first compound DF, which is a delayed fluorescent material that has been converted into an ICT complex state by reverse intersystem crossing (RISC), to the second compound FD, which is a fluorescent material. In order to realize such an organic light emitting diode D1, it is necessary to realize an organic light emitting diode D1 having high efficiency and high color purity by efficiently transferring exciton energy from the first compound DF, which can be a delayed fluorescent material, to the second compound FD, which is a fluorescent material by reverse intersystem crossing (RISC). DF ) is the excited singlet energy level (S1 FD ) higher than the excited triplet energy level (T1 DF ) is the excited triplet energy level (T1 FD ) may be higher.

[0148] The second compound FD can utilize all of the singlet exciton energy and triplet exciton energy of the first compound DF for light emission, thereby maximizing the luminous efficiency of the organic light-emitting diode D1. Furthermore, quenching such as TTA or TPA is minimized, and the luminous life of the organic light-emitting diode D1 can be greatly improved.

[0149] Returning again to FIG. 3, 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 inorganic, and the hole transport layer 260, which is organic. In one exemplary aspect, the hole injection layer 250 is made of any one of the following compounds: 4,4',4"-tris(3-methylphenylamino)triphenylamine; MTDATA, 4,4',4"-tris(N,N-diphenylamino)triphenylamine; NATA, 4,4',4"-tris(N-(naphthalen-1-yl)-N-phenylamino)triphenylamine; 1T-NATA, 4,4',4"-tris(N-(naphthalen-2-yl)-N-phenylamino)triphenylamine; 2T-NATA, copper phthalocyanine; CuPC, tris(4-carbazolyl-9-yl-phenyl)amine; TCTA, N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4"-diamine; NPB; NPD, 1,4,5,8,9, The organic light-emitting diode D1 may include, but is not limited to, a compound selected from the group consisting of 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-ethylenedioxythiophene)polystyrenesulfonic acid; PEDOT / PSS, N-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine, and combinations thereof. Depending on the characteristics of the organic light-emitting diode D1, the hole injection layer 250 may be omitted.

[0150] The hole transport layer 260 is located between the hole injection layer 250 and the light emitting material layer 240. In one exemplary aspect, the hole transport layer 260 is selected from the group consisting of N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine; TPD, NPB (NPD), CBP, poly[N,N'-bis(4-butylphenyl)-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-tolylamino)phenyl]silane; The amines may include, but are not limited to, compounds selected from the group consisting of cyclohexane; TAPC, 3,5-di(9H-carbazol-9-yl)-N,N-diphenylaniline; DCDPA, N-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine, N-(biphenyl-4-yl)-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)biphenyl)-4-amine, and combinations thereof.

[0151] 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 constituting the electron transport layer 270 is required to have high electron mobility and to stably supply electrons to the light emitting material layer 240 by 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, and a triazine-based compound.

[0152] More specifically, the electron transport layer 270 may be selected from the group consisting of 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-N1,08)-(1,1′-biphenyl-4-olato)aluminum; BAlq, 4,7-diphenyl-1,10-phenanthroline; Bphen, 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline; NBphen, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline; BCP, 3-(4-biphenyl)-4-phenyl-1,10-phenanthroline; The compound may include, but is not limited to, a compound selected from the group consisting of nyl-5-tert-butylphenyl-1,2,4-triazole; TAZ, 4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole; NTAZ, 1,3,5-tris(p-pyrid-3-yl-phenyl)benzene; TpPyPB, 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine; TmPPYTz, poly[(9,9-bis(3'-((N,N-dimethyl)-N-ethylammonium)-propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)]; PFNBr, tris(phenylquinoxaline); TPQ, TSPO1, and combinations thereof.

[0153] The electron injection layer 280 is located between the second electrode 230 and the electron transport layer 270, and can improve the characteristics of the second electrode 270 and extend the life of the device. In one exemplary aspect, the material of the electron injection layer 280 can be, but is not limited to, an alkali metal halide material such as LiF, CsF, NaF, BaF2, and / or an alkaline earth metal halide material, and / or an organometallic material such as Liq, lithium benzoate, and sodium stearate.

[0154] If holes move to the second electrode 230 through the light emitting material layer 240, or if electrons move to the first electrode 210 through the light emitting material layer 240, the light emitting lifetime and light emitting efficiency of the organic light emitting diode D1 may decrease. To prevent this, the organic light emitting diode D1 according to the first exemplary embodiment of the present invention may have an exciton blocking layer adjacent to the light emitting material layer 240.

[0155] The organic light emitting diode D1 according to the first embodiment of the present invention may have an electron blocking layer 265 capable of controlling and preventing electron transfer between the hole transport layer 260 and the light emitting material layer 240. In one exemplary aspect, the electron blocking layer 265 may include, but is not limited to, a compound selected from the group consisting of 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, mCP, mCBP, CuPC, N,N'-bis[4-[bis(3-methylphenyl)amino]phenyl]-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine; DNTPD, TDAPB, 3,6-bis(N-carbazolyl)-N-phenyl-carbazole, and combinations thereof.

[0156] A hole blocking layer 275 is positioned between the light emitting material layer 240 and the electron transport layer 270 as a second exciton blocking layer to prevent hole movement between the light emitting material layer 240 and the electron transport layer 270. In one exemplary aspect, the material of the hole blocking layer 275 can be any one of oxadiazole-based compounds, triazole-based compounds, phenanthroline-based compounds, benzoxazole-based compounds, benzothiazole-based compounds, benzimidazole-based compounds, and triazine-based compounds that can be used for the electron transport layer 270.

[0157] For example, the hole blocking layer 275 can include, but is not limited to, 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, DPEPO, 9-(6-(9H-carbazol-9-yl)pyridin-3-yl)-9H-3,9'-bicarbazole, and combinations thereof, which have a lower HOMO energy level than the material used in the light emitting layer 240.

[0158] In the above-described first embodiment, the first compound and the second compound having delayed fluorescence characteristics are included in the same luminescent material layer, but the first compound and the second compound may be included in adjacent luminescent material layers. This will be described. FIG. 8 is a cross-sectional view showing an organic light-emitting diode according to an exemplary second embodiment of the present invention, FIG. 9 is a schematic diagram showing a state in which the HOMO energy levels of the first compound and the second compound constituting the luminescent material layer according to the second embodiment of the present invention are adjusted and holes are efficiently transferred to the second compound, and FIG. 10 is a schematic diagram showing a light-emitting mechanism due to the singlet energy level and the triplet energy level between luminescent materials in the luminescent material layer constituting the organic light-emitting diode according to the second embodiment of the present invention.

[0159] 8, an organic light emitting diode D2 according to a second embodiment of the present invention includes a first electrode 210 and a second electrode 230 facing each other, and an emission layer 220A located between the first electrode 210 and the second electrode 230. The organic light emitting display device 100 (see FIG. 2) 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 the blue pixel region.

[0160] In an exemplary aspect, the light emitting layer 220A includes a light emitting material layer 240A. 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.

[0161] Furthermore, the light emitting layer 220A may further include at least one of a hole injection layer located between the first electrode 210 and the hole transport layer 260, and an electron injection layer 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 located between the light emitting material layer 240A and the hole transport layer 260, and / or a hole blocking layer 275 located between the light emitting material layer 240A and the electron transport layer 270. The configuration of the light emitting layer 220A, excluding the first electrode 210, the second electrode 230, and the light emitting material layer 240A, may be the same as that of the first embodiment described above.

[0162] Luminescent material layer 240A includes a first luminescent material layer 242 (EML1, bottom luminescent material layer, first layer) positioned between electron blocking layer 265 and hole blocking layer 275, and a second luminescent material layer 244 (EML2, top luminescent material layer, second layer) positioned between first luminescent material layer 242 and hole blocking layer 275. Optionally, second luminescent material layer 244 may be positioned between electron blocking layer 265 and first luminescent material layer 242.

[0163] One of the first luminescent material layer 242 (EML1) and the second luminescent material layer 244 (EML2) contains a first compound DF (first dopant) which is a delayed fluorescent material, and the other contains a second compound FD (second dopant) which is a fluorescent material. In addition, the first luminescent material layer 242 (EML1) and the second luminescent material layer 244 (EML2) can each contain a third compound H1 which can be a first host and a fourth compound H2 which can be a second host. For example, the first luminescent material layer 242 can contain the first compound DF and the third compound H1, and the second luminescent material layer 244 can contain the second compound FD and the fourth compound H2.

[0164] The first compound DF constituting the first light emitting material layer 242 (EML1) may be a delayed fluorescent material having the structure of chemical formulas (1) to (6). The first compound DF having delayed fluorescent properties converts triplet exciton energy of the first compound DF into singlet exciton energy by reverse intersystem crossing (RISC). The first compound DF has high quantum efficiency, but has a wide half-width, resulting in poor color purity.

[0165] Meanwhile, the second light emitting material layer 244 (EML2) contains a second compound FD, which is a fluorescent material. The second compound FD contains any organic compound having the structure of chemical formulas (7) to (9). The second compound FD, which is a fluorescent material having the structure of chemical formulas (7) to (9), has a narrower half width than the first compound DF (for example, the half width is 35 nm or less). Therefore, the second compound FD has an advantage in terms of color purity.

[0166] According to this embodiment, the singlet exciton energy and triplet exciton energy of the first compound DF having delayed fluorescence properties contained in the first luminescent material layer 242 (EML1) are transferred to the second compound FD contained in the adjacent second luminescent material layer 244 (EML2) via the FRET mechanism, and finally, the second compound FD emits light.

[0167] By reverse intersystem crossing (RISC), triplet exciton energy of the first compound DF contained in the first luminescent material layer 242 (EML1) is converted to singlet exciton energy. The singlet exciton energy of the first compound DF moves to the singlet energy level of the second compound FD. The second compound FD contained in the second luminescent material layer 244 (EML2) utilizes both the singlet exciton energy and the triplet exciton energy for emission.

[0168] The exciton energy generated in the first compound DF, which may be a delayed fluorescent material contained in the first light emitting material layer 242 (EML1), is efficiently transferred to the second compound FD, which may be a fluorescent material contained in the second light emitting material layer 244 (EML2), to realize superfluorescence. At this time, substantial light emission occurs in the second light emitting material layer 244 (EML2) containing the second compound FD, which is a fluorescent material. As a result, the quantum efficiency of the organic light emitting diode D2 is improved, the half width is narrowed, and the color purity is improved.

[0169] The first light emitting material layer 242 (EML1) and the second light emitting material layer 244 (EML2) each include a third compound H1 and a fourth compound H2. The third compound H1 and the fourth compound H2 may be the same as or different from each other. For example, the third compound H1 and the fourth compound H2 may each independently include the third compound H described in the first embodiment, but are not limited thereto.

[0170] As shown in FIG. 9, the HOMO energy level of the first compound DF (HOMO DF ) and the HOMO energy level of the second compound FD (HOMO FD The energy band gap (ΔHOMO-1) between the first compound DF and the second compound FD can satisfy the above-mentioned formula (I) or formula (II). Therefore, the holes injected into the light-emitting material layer 240 are transferred to the first compound DF, and the first compound DF can transfer the exciton energy to the second compound FD by utilizing all of the singlet exciton energy and the triplet exciton energy. In addition, the LUMO energy level (LUMO DF ) is the LUMO energy level of the second compound FD (LUMO FD ) or the same as the above and may satisfy formula (III) or formula (IV).

[0171] Furthermore, the HOMO energy levels of the third compound H1 and the fourth compound H2 (HOMO H1 , HOMO H2 ) and the HOMO energy level of the first compound DF (HOMO DF ) difference (|HOMO H -HOMODF |), or the LUMO energy levels of the third compound H1 and the fourth compound H2 (LUMO H1 , LUMO H2 ) and the LUMO energy level of the first compound DF (LUMO DF ) difference (|LUMO H -LUMO FD |) may be about 0.5 eV or less. If such a condition is not satisfied, non-radiative annihilation may occur in the first compound DF, or exciton energy may not be transferred from the third compound H1 and the fourth compound H2 to the first compound DF and / or the second compound FD, resulting in a decrease in quantum efficiency of the organic light-emitting diode D2.

[0172] Meanwhile, the exciton energy generated in the third compound H1 and the fourth compound H2, which may be included in the first light-emitting material layer 242 (EML1) and the second light-emitting material layer 244 (EML2), respectively, must first be transferred to the first compound DF, which may be a delayed fluorescent material, and emit light. As shown in FIG. 10, the excited singlet energy level (S1 H1 ) and the excited singlet energy level of the quaternary compound H2 (S1 H2 ) are the excited singlet energy levels (S1 DF ) is higher than the excited triplet energy level (T1 H1 ) and the excited singlet energy level (T1 H2 ) are the excited triplet energy levels (T1 DF ) higher than the excited triplet energy level (T1 H1 , T1 H2 ) is the excited triplet energy level (T1 DF ) may be at least about 0.2 eV or more, for example, about 0.3 eV or more, or about 0.5 eV or more higher.

[0173] On the other hand, the excited singlet energy level (S1 H2 ) is the excited singlet energy level (S1FD ) higher than the excited triplet energy level (T1 H2 ) is the excited triplet energy level (T1 FD ) so that the singlet exciton energy generated in the fourth compound H2 can be transferred to the singlet energy level of the second compound FD.

[0174] Furthermore, exciton energy must be efficiently transferred from the first compound DF, which has been converted to an ICT complex state by reverse intersystem crossing (RISC) in the first luminescent material layer 242 (EML1), to the second compound FD in the second luminescent material layer 244 (EML2). In order to realize such an organic light-emitting diode D2, the excited singlet energy level (S1 DF ) is the excited singlet energy level (S1 FD ) higher than the excited triplet energy level (T1 DF ) is the excited triplet energy level (T1 FD ) may be higher.

[0175] In each of the first luminescent material layer 242 and the second luminescent material layer 244, the third compound H1 and the fourth compound H2 may be contained in a content greater than or equal to the first compound DF and the second compound FD constituting the same luminescent material layer, respectively. The content of the first compound DF contained in the first luminescent material layer 242 (EML1) may be greater than the content of the second compound FD contained in the second luminescent material layer 244 (EML2). This allows sufficient energy transfer by FRET from the first compound DF contained in the first luminescent material layer 242 (EML1) to the second compound FD contained in the second luminescent material layer 244 (EML2).

[0176] For example, the first compound DF in the first luminescent material layer 242 (EML1) may be about 1% to about 50% by weight, such as about 10% to about 40% by weight, or about 20% to about 40% by weight. The second compound FD in the second luminescent material layer 244 (EML2) may be about 1% to about 10% by weight, such as about 1% to about 5% by weight.

[0177] Optionally, when the second light emitting layer 244 (EML2) is adjacent to the hole blocking layer 275, the fourth compound H2 constituting the second light emitting layer 244 (EML2) may be the same material as that of the hole blocking layer 275. In this case, the second light emitting layer 244 (EML2) may have a hole blocking function as well as a light emitting function. In other words, the second light emitting layer 244 (EML2) functions as a buffer layer for blocking holes. Meanwhile, the hole blocking layer 275 may be omitted, in which case the second light emitting layer 244 (EML2) is used as a light emitting layer and a hole blocking layer.

[0178] In another exemplary aspect, when the second light emitting material layer 244 (EML2) is located adjacent to the electron blocking layer 265, the fourth compound H2 constituting the second light emitting material layer 244 (EML2) may be the same material as that of the electron blocking layer 265. In this case, the second light emitting material layer 244 (EML2) may have an electron blocking function as well as a light emitting function. In other words, the second light emitting material layer 244 (EML2) functions as a buffer layer for blocking electrons. Meanwhile, the electron blocking layer 265 may be omitted, in which case the second light emitting material layer 244 (EML2) is used as a light emitting material layer and an electron blocking layer.

[0179] Next, an organic light-emitting diode having a three-layer structure of the light-emitting material layer will be described. Fig. 11 is a cross-sectional view showing an organic light-emitting diode according to a third exemplary embodiment of the present invention. Fig. 12 is a schematic diagram showing a state in which the HOMO energy levels of a first compound and a second compound constituting the light-emitting material layer according to the third embodiment of the present invention are adjusted, and holes are efficiently transferred to the second compound. Fig. 13 is a schematic diagram showing a light-emitting mechanism due to the singlet energy level and triplet energy level between light-emitting materials in the light-emitting material layer constituting the organic light-emitting diode according to the third embodiment of the present invention.

[0180] 11, an organic light emitting diode D3 according to a third embodiment of the present invention includes a first electrode 210 and a second electrode 230 facing each other, and an emission layer 220B located between the first electrode 210 and the second electrode 230. The organic light emitting display device 100 (see FIG. 2) includes a red pixel region, a green pixel region, and a blue pixel region, and the organic light emitting diode D3 may be located in the blue pixel region.

[0181] In an exemplary aspect, the light-emitting layer 220B includes a three-layer structure of the light-emitting material layer 240B. The light-emitting layer 220B can include at least one of a hole transport layer 260 located between the first electrode 210 and the light-emitting material layer 240B and an electron transport layer 270 located between the light-emitting material layer 240B and the second electrode 230. The light-emitting layer 220B can also 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 220B can further include an electron blocking layer 265 located between the light-emitting material layer 240B and the hole transport layer 260, and / or a hole blocking layer 275 located between the light-emitting material layer 240B and the electron transport layer 270. The remaining components of the light emitting layer 220B, except for the first electrode 210, the second electrode 230, and the light emitting material layer 240B, may be substantially similar to those of the first and second embodiments described above.

[0182] The luminescent material layer 240B (EML) includes a first luminescent material layer 242 (EML1, middle luminescent material layer, first layer) located between the electron blocking layer 265 and the hole blocking layer 275, a second luminescent material layer 244 (EML2, lower luminescent material layer, second layer) located between the electron blocking layer 265 and the first luminescent material layer 242 (EML1), and a third luminescent material layer 246 (EML3, upper luminescent material layer, third layer) located between the first luminescent material layer 242 (EML1) and the hole blocking layer 275.

[0183] The first luminescent material layer 242 (EML1) includes a first compound DF (first dopant) which is a delayed fluorescent material, and the second luminescent material layer 244 and the third luminescent material layer 246 each include a second compound FD1 (second dopant) and a fifth compound FD2 (third dopant) which may be fluorescent materials. The first to third luminescent material layers 242, 244, and 246 may further include a third compound H1, a fourth compound H2, and a sixth compound H3 which may be first to third hosts, respectively.

[0184] In this embodiment, the singlet exciton energy and triplet exciton energy of the first compound DF, which is a delayed fluorescent material contained in the first luminescent material layer 242 (EML1), are transferred to the second compound FD1, which is a fluorescent material contained in the adjacent second luminescent material layer 244 (EML2) and third luminescent material layer 246 (EML3), respectively, and then to the fifth compound FD2 by the mechanism of Förster resonance energy transfer (FRET), and final emission occurs in the second compound FD1 and the fifth compound FD2.

[0185] The triplet exciton energy of the first compound DF contained in the first luminescent material layer 242 (EML1) is converted into singlet exciton energy by reverse intersystem crossing. The excited singlet energy level of the first compound DF, which is a delayed fluorescent material, is higher than the excited singlet energy levels of the second compound FD1 and the fifth compound FD2, which are fluorescent materials contained in the adjacent second luminescent material layer 244 (EML2) and the third luminescent material layer 246 (EML3), respectively. The singlet exciton energy of the first compound DF contained in the first luminescent material layer 242 (EML1) is transferred to the excited singlet energy levels of the second compound FD1 and the fifth compound FD2 contained in the adjacent second luminescent material layer 244 (EML2) and the third luminescent material layer 246 (EML3) via FRET.

[0186] Therefore, the second compound FD1 and the fifth compound FD2 contained in the second light emitting material layer 244 (EML2) and the third light emitting material layer 246 (EML3), respectively, utilize all of the singlet exciton energy and the triplet exciton energy for light emission. The second compound FD1 and the fifth compound FD2 have a narrower half-width than the first compound DF (for example, the half-width is 35 nm or less). Therefore, the quantum efficiency of the organic light emitting diode D4 is improved, the half-width is narrowed, and the color purity is improved. At this time, substantial light emission occurs in the second light emitting material layer 242 (EML2) and the third light emitting material layer 246 (EML3), which contain the second compound FD1 and the fifth compound FD2, respectively.

[0187] The first compound DF, which is a delayed fluorescent material, contains an organic compound having the structure of chemical formulas (1) to (6), and the second compound FD1 and the fifth compound FD2, which are fluorescent materials, each independently contain a boron-based organic compound having the structure of chemical formulas (7) to (9). The third compound H1, the fourth compound H2, and the sixth compound H3 may be the same as or different from each other. For example, the third compound H1, the fourth compound H2, and the sixth compound H3 may each independently contain the third compound H described in the first embodiment, but are not limited thereto.

[0188] As in the first and second embodiments described above, the HOMO energy level of the first compound DF (HOMO DF ) and the HOMO energy levels of the second compound FD1 and the fifth compound FD2 (HOMO FD , HOMO DF3 ) can satisfy the above-mentioned formula (I) or formula (II). Therefore, the holes injected into the light-emitting material layer 240 are transferred to the first compound DF, and the first compound DF can transfer the exciton energy to the second compound FD1 and the fifth compound FD2 by utilizing all the singlet exciton energy and triplet exciton energy. In addition, the LUMO energy level (LUMO DF ) are the LUMO energy levels (LUMO FD , LUMO DF3 ) or the same as the above and satisfy formula (III) or formula (IV).

[0189] Furthermore, the HOMO energy levels of the third compound H1, the fourth compound H2, and the sixth compound H3 (HOMO H1 , HOMO H2 , HOMO H3 ) and the HOMO energy level of the first compound DF (HOMO DF ) difference (|HOMO H -HOMO DF |), or the LUMO energy levels of the third compound H1, the fourth compound H2, and the sixth compound H3 (LUMO H1 , LUMO H2 , LUMO H3 ) and the LUMO energy level of the first compound DF (LUMO DF ) difference (|LUMO H -LUMO DF |) can be 0.5 eV or less.

[0190] In order to achieve efficient light emission, it is necessary to appropriately adjust the energy levels of the light emitting materials contained in the first to third light emitting material layers 242, 244, and 246 (EML1, EML2, and EML3). Referring to FIG. 13, the excited singlet energy level (S1 H1 ), the excited singlet energy level (S1 H2 ), and the excited singlet energy level (S1 H3 ) is the excited singlet energy level (S1 DF ) is higher than the excited triplet energy level (T1 H1 ), the excited triplet energy level of the fourth compound H2 (T1 H2 ), and the excited triplet energy level (T1 H3 ) are the excited triplet energy levels (T1 DF ) higher.

[0191] The exciton energy must be efficiently transferred from the first compound DF, which has been converted to an ICT complex state by reverse intersystem crossing (RISC) in the first luminescent material layer 242 (EML1), to the second compound FD1 and the fifth compound FD2, which are fluorescent materials contained in the second luminescent material layer 244 (EML2) and the third luminescent material layer 246 (EML3), respectively. In order to realize such an organic light-emitting diode D3, the excited singlet energy level (S1 DF ) is the excited singlet energy level (S1 FD1 , S1 FD2 ) higher than the excited triplet energy level (T1 DF ) are the excited triplet energy levels (T1 FD1 , T1 FD2 ) may be higher.

[0192] In addition, it is necessary to prevent the energy transferred from the first compound DF, which is a delayed fluorescent material, to the second compound FD1 and the fifth compound FD2, which are fluorescent materials, from transferring to the fourth compound H2 and the sixth compound H3, thereby realizing efficient light emission. For this purpose, it is necessary to prevent the energy transferred from the first compound DF, which is a delayed fluorescent material, to the second compound FD1 and the fifth compound FD2, which are fluorescent materials, from transferring to the fourth compound H2 and the sixth compound H3, which can be a third host ... by preventing the energy transferred from the first compound DF, which is a delayed fluorescent material, to the fourth compound H2 and the sixth compound H3, which can be a third host, from transferring to the fourth compound H2 and the sixth compound H3. H2 , S1 H3 ) are the excited singlet energy levels (S1 FD1 , S1 FD2 ) higher than the excited triplet energy level (T1 H2 , T1 H3 ) are the excited triplet energy levels (T1 FD1 , T1 FD2 ) may be higher.

[0193] The first compound DF contained in the first luminescent material layer 242 (EML1) may be contained in a content greater than the second compound FD1 and the fifth compound FD2 contained in the second luminescent material layer 244 (EML2) and the third luminescent material layer 246 (EML3), respectively. In this case, energy can be sufficiently transferred by FRET from the first compound DF contained in the first luminescent material layer 242 (EML1) to the second compound FD1 and the fifth compound FD2 contained in the second luminescent material layer 244 (EML2) and the third luminescent material layer 246 (EML3), respectively.

[0194] For example, the content of the first compound DF in the first luminescent material layer 242 (EML1) may be about 1% by weight to about 50% by weight, for example, about 10% by weight to about 40% by weight, or about 20% by weight to about 40% by weight. In each of the second luminescent material layer 244 (EML2) and the third luminescent material layer 246 (EML3), the content of the second compound FD1 and the fifth compound FD2 may be about 1% by weight to about 10% by weight, for example, about 1% by weight to about 5% by weight.

[0195] Optionally, when the second luminescent material layer 244 (EML2) is located adjacent to the electron blocking layer 265, the fourth compound H2 constituting the second luminescent material layer 244 (EML2) may be the same material as that of the electron blocking layer 265. In this case, the second luminescent material layer 244 (EML2) may have an electron blocking function as well as a light emitting function. In other words, the second luminescent material layer 244 (EML2) functions as a buffer layer for blocking electrons. Meanwhile, the electron blocking layer 265 may be omitted, in which case the second luminescent material layer 244 (EML2) is used as both a luminescent material layer and an electron blocking layer.

[0196] In addition, when the third light emitting material layer 246 (EML3) is located adjacent to the hole blocking layer 275, the sixth compound H3 constituting the third light emitting material layer 246 (EML3) may be the same material as that of the hole blocking layer 275. In this case, the third light emitting material layer 246 (EML3) may have a hole blocking function as well as a light emitting function. In other words, the third light emitting material layer 246 (EML3) functions as a buffer layer for blocking holes. Meanwhile, the hole blocking layer 275 may be omitted, in which case the third light emitting material layer 246 (EML3) is used as a light emitting material layer and a hole blocking layer.

[0197] In another exemplary aspect, the fourth compound H2 constituting the second light emitting material layer 244 (EML2) may be the same material as the electron blocking layer 265, and the sixth compound H3 constituting the third light emitting material layer 246 (EML3) may be the same material as the hole blocking layer 275. In this case, the second light emitting material layer 244 (EML2) may have an electron blocking function as well as a light emitting function, and the third light emitting material layer 246 (EML3) may have a hole blocking function as well as a light emitting function. That is, the second light emitting material layer 244 (EML2) and the third light emitting material layer 246 (EML3) may function as buffer layers blocking electrons and holes, respectively. Meanwhile, the electron blocking layer 265 and the hole blocking layer 275 may be omitted, in which case the second light emitting material layer 244 (EML2) is used as a light emitting material layer and an electron blocking layer, and the third light emitting material layer 246 (EML3) is used as a light emitting material layer and a hole blocking layer.

[0198] In an alternative embodiment, the organic light emitting diode may include two or more light emitting portions. Figure 14 is a cross-sectional view illustrating an organic light emitting diode according to a fourth exemplary embodiment of the present invention.

[0199] 14, the organic light emitting diode D4 includes a first electrode 210 and a second electrode 230 facing each other, and an emitting layer 220C located between the first electrode 210 and the second electrode 230. The organic light emitting display device 100 (see FIG. 2) 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 the blue pixel region. In addition, the first electrode 210 may be an anode, and the second electrode 230 may be a cathode.

[0200] The light emitting layer 220C includes a first light emitting unit 320 including a first light emitting material layer 340, and a second light emitting unit 420 including a second light emitting material layer 440. The light emitting layer 220C may further include a charge generation layer (CGL) 380 located between the first light emitting unit 320 and the second light emitting unit 420.

[0201] The charge generation layer 380 is located between the first light emitting unit 320 and the second light emitting unit 420, and the first light emitting unit 320, the charge generation layer 380, and the second light emitting unit 420 are sequentially stacked on the first electrode 210. That is, the first light emitting unit 320 is located between the first electrode 310 and the charge generation layer 380, and the second light emitting unit 420 is located between the second electrode 230 and the charge generation layer 380.

[0202] The first light emitting unit 320 includes a first light emitting layer 340 (EML1, lower light emitting layer). The first light emitting unit 320 may further include at least one of a hole injection layer 350 (HIL) located between the first electrode 210 and the first light emitting layer 340, a first hole transport layer 360 (HTL1) located between the first light emitting layer 340 and the hole injection layer 350, and a first electron transport layer 370 (ETL1) located between the first light emitting layer 340 and the charge generation layer 380. Optionally, the first light emitting unit 320 may further include at least one of a first electron blocking layer 365 (EBL1) located between the first hole transport layer 360 and the first light emitting layer 340, and a first hole blocking layer 375 (HBL1) located between the first light emitting layer 340 and the first electron transport layer 370.

[0203] The second light emitting unit 420 includes a second light emitting material layer 440 (EML2, upper light emitting material layer). The second light emitting unit 420 may further include at least one of a second hole transport layer 460 (HTL2) located between the charge generating layer 380 and the second light emitting material layer 440, a second electron transport layer 470 (ETL2) located between the second light emitting material layer 440 and the second electrode 230, and an electron injection layer 480 (EIL) located between the second electron transport layer 470 and the second electrode 230. Optionally, the second light emitting unit 420 may further include at least one of a second electron blocking layer 465 (EBL2) located between the second hole transport layer 460 and the second light emitting material layer 440, and a second hole blocking layer 475 (HBL2) located between the second light emitting material layer 440 and the second electron transport layer 470.

[0204] The charge generation layer 380 is located between the first light emitting unit 320 and the second light emitting unit 420. In other words, the first light emitting unit 320 and the second light emitting unit 420 are connected via the charge generation layer 380. The charge generation layer 380 may be a PN type in which an N-type charge generation layer 382 and a P-type charge generation layer 384 are joined together.

[0205] The N-type charge generation layer 382 is located between the first electron transport layer 370 and the second hole transport layer 460, and the P-type charge generation layer 384 is located between the N-type charge generation layer 382 and the second hole transport layer 460. The N-type charge generation layer 382 transfers electrons to the first light emitting material layer 340 of the first light emitting unit 320, and the P-type charge generation layer 384 transfers holes to the second light emitting material layer 440 of the second light emitting unit 420.

[0206] In this embodiment, the first luminescent material layer 340 and the second luminescent material layer 440 may each be a blue luminescent material layer. For example, at least one of the first luminescent material layer 340 and the second luminescent material layer 440 may include a first compound DF that is a delayed fluorescent material, a second compound FD that is a fluorescent material, and optionally a third compound H that is a host.

[0207] When the first luminescent material layer 340 and / or the second luminescent material layer 440 includes a first compound DF, a second compound FD, and a third compound H, the content of the third compound H in the first luminescent material layer 340 and / or the second luminescent material layer 440 may be greater than the content of the first compound DF, and the content of the first compound DF may be greater than the content of the second compound FD. When the content of the first compound DF is greater than the content of the second compound FD, energy can be sufficiently transferred from the first compound DF to the second compound FD.

[0208] In one exemplary aspect, second luminescent material layer 440 can include a first compound DF and a second compound FD, similar to first luminescent material layer 340, and can optionally include a third compound H. Alternatively, second luminescent material layer 440 can include a compound different from at least one of the first compound DF and the second compound FD included in first luminescent material layer 340, and can emit light at a different wavelength or have a different luminous efficiency than first luminescent material layer 340.

[0209] In FIG. 14, the first luminescent material layer 340 and the second luminescent material layer 440 each have a single-layer structure, but the first luminescent material layer 340 and the second luminescent material layer 440, which may each contain at least a first compound DF, a second compound FD, and optionally a third compound H, may each be a two-layer structure (see FIG. 8) or a three-layer structure (see FIG. 11).

[0210] In the organic light emitting diode D4 according to this embodiment, the singlet exciton energy of the first compound DF, which is a delayed fluorescent material, is transferred to the second compound FD, which is a fluorescent material, and the second compound FD finally emits light. As a result, the luminous efficiency and color purity of the organic light emitting diode D4 are improved. In addition, the first compound DF having the structure of chemical formulas (1) to (6) and the second compound FD having the structure of chemical formulas (7) to (9) are used in at least the first light emitting material layer 340, so that the luminous efficiency and color purity of the organic light emitting diode D4 are further improved. In addition, since the organic light emitting diode D4 has a double stack structure of blue light emitting material layers, the color purity of the organic light emitting diode D4 can be improved or the luminous efficiency can be optimized.

[0211] 15 is a cross-sectional view illustrating an organic light emitting display device according to a second embodiment of the present invention. As illustrated in FIG. 15, the organic light emitting display device 500 includes a substrate 510 having first to third pixel regions P1, P2, and P3 defined therein, a thin film transistor Tr located on the substrate 510, and an organic light emitting diode D located on 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.

[0212] The substrate 510 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 buffer layer 512 is formed on the substrate 510, and a thin film transistor Tr is formed on the buffer layer 512. The buffer layer 512 may be omitted. As described with reference to FIG. 2, the thin film transistor Tr includes a semiconductor layer, a gate electrode, a source electrode, and a drain electrode, and serves as a driving element.

[0213] A planarization layer 550 is located on the thin film transistor Tr. The planarization layer 550 has a flat upper surface and has a drain contact hole 552 that exposes the drain electrode of the thin film transistor Tr.

[0214] The organic light emitting diode D is located on the planarization layer 550, and includes a first electrode 610 connected to the drain electrode of the thin film transistor Tr, and a light emitting layer 620 and a second electrode 630 sequentially stacked on the first electrode 610. The organic light emitting diodes D are located in the first to third pixel regions P1, P2, and P3, respectively, and emit light of different colors. For example, the organic light emitting diode D in the first pixel region P1 can emit blue light, the organic light emitting diode D in the second pixel region P2 can emit green light, and the organic light emitting diode D in the third pixel region P3 can emit red light.

[0215] The first electrode 610 is formed separately for each of the first to third pixel regions P1, P2, and P3, and the second electrode 630 is formed integrally corresponding to the first to third pixel regions P1, P2, and P3. The first electrode 610 may be one of an anode and a cathode, and the second electrode 630 may be the other. In addition, one of the first electrode 610 and the second electrode 630 may be a transmissive electrode (or a semi-transmissive electrode), and the other may be a reflective electrode.

[0216] For example, the first electrode 610 is an anode and may include a conductive material having a relatively large work function, such as a transparent conductive oxide layer made of a transparent conductive oxide (TCO). The second electrode 630 is a cathode and may include a conductive material having a relatively small work function, such as a metal material layer made of a low-resistance metal. For example, the first electrode 610 may include any one of ITO, IZO, ITZO, SnO, ZnO, ICO, and AZO, and the second electrode 630 may be made of Al, Mg, Ca, Ag, or an alloy thereof (e.g., an Mg-Ag alloy), or a combination thereof.

[0217] When the organic light emitting display device 500 is a bottom emission type, the first electrode 610 may have a single layer structure of a transparent conductive oxide layer. Meanwhile, when the organic light emitting display device 500 is a top emission type, a reflective electrode or a reflective layer may be further formed under the first electrode 610. For example, the reflective electrode or the reflective layer may be made of silver or an aluminum-palladium-copper (APC) alloy. In the organic light emitting diode D, which is a top emission type, the first electrode 610 may have a three-layer structure of ITO / Ag / ITO or ITO / APC / ITO. Also, the second electrode 630 may be thin and have a light transmission (semi-transmission) characteristic.

[0218] A bank layer 560 is formed on the planarizing layer 550 to cover the ends of the first electrodes 610. The bank layers 560 correspond to the first to third pixel regions P1, P2, and P3, respectively, and expose the centers of the first electrodes 610.

[0219] The light emitting layer 620 is formed on the first electrode 610. The light emitting layer 620 may have a single-layer structure of a light emitting material layer (EML). Alternatively, the light emitting layer 620 may include at least one of a hole injection layer (HIL), a hole transport layer (HTL), and / or an electron blocking layer (EBL) sequentially stacked between the first electrode 610 and the light emitting material layer, and a hole blocking layer (HBL), an electron transport layer (ETL), an electron injection layer (EIL), and / or a charge generation layer (CGL) sequentially stacked between the light emitting material layer and the second electrode 630.

[0220] In the first pixel region P1, which is a blue pixel region, the luminescent material layer constituting the luminescent layer 620 includes a first compound DF which is a delayed fluorescent material having the structure of chemical formulas (1) to (6), a second compound FD which is a fluorescent material having the structure of chemical formulas (7) to (9), and may optionally include a third compound H which is a host.

[0221] A moisture preventing film 570 is formed on the second electrode 630 to prevent external moisture from penetrating into the organic light emitting diode D. The moisture preventing film 570 may have a three-layer structure including a first inorganic insulating layer, an organic insulating layer, and a second inorganic insulating layer, but is not limited thereto.

[0222] The organic light emitting display device 500 may further include a polarizer for reducing reflection of external light. For example, the polarizer may be circular. If the organic light emitting display device 500 is a bottom emission type, the polarizer may be disposed under the substrate 510. On the other hand, if the organic light emitting display device 500 is a top emission type, the polarizer may be disposed over the encapsulation film 570.

[0223] 16 is a cross-sectional view illustrating an organic light-emitting diode according to a fifth exemplary embodiment of the present invention. The organic light-emitting diode D5 includes a first electrode 610, a second electrode 630, and a light-emitting layer 620 located between the first electrode 610 and the second electrode 630.

[0224] The first electrode 610 may be an anode and the second electrode 630 may be a cathode. For example, the first electrode 610 may be a reflective electrode and the second electrode 630 may be a transmissive electrode (semi-transmissive electrode).

[0225] The light-emitting layer 620 includes a light-emitting material layer 640. The light-emitting layer 620 may also include at least one of a hole transport layer 660 (HTL) located between the first electrode 610 and the light-emitting material layer 640 and an electron transport layer 670 (ETL) located between the light-emitting material layer 640 and the second electrode 630. The light-emitting layer 620 may also include at least one of a hole injection layer 650 (HIL) located between the first electrode 610 and the hole transport layer 660 and an electron injection layer 680 (EIL) located between the electron transport layer 670 and the second electrode 630. Optionally, the light-emitting layer 620 may also include at least one of an electron blocking layer 665 (EBL) located between the hole transport layer 660 and the light-emitting material layer 640 and a hole blocking layer 675 (HBL) located between the light-emitting material layer 640 and the electron transport layer 670.

[0226] In addition, the light-emitting layer 620 may further include an auxiliary hole transport layer 662 located between the hole transport layer 660 and the electron blocking layer 665. The auxiliary hole transport layer 662 may include a first auxiliary hole transport layer 662a located in the first pixel region P1, a second auxiliary hole transport layer 662b located in the second pixel region P2, and a third auxiliary hole transport layer 662c located in the third pixel region P3.

[0227] The first auxiliary hole transport layer 662a has a first thickness, the second auxiliary hole transport layer 662b has a second thickness, and the third auxiliary hole transport layer 662c 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. Therefore, the organic light emitting diode D5 has a microcavity structure.

[0228] That is, since the thicknesses of the first to third auxiliary hole transport layers 662a, 662b, and 662c are different from each other, the distance between the first electrode 610 and the second electrode 630 in the first pixel region P1 that emits light in the first wavelength range (blue) is smaller than the distance between the first electrode 610 and the second electrode 630 in the second pixel region P2 that emits light in the second wavelength range (green) longer than the first wavelength range. Also, the distance between the first electrode 610 and the second electrode 630 in the second pixel region P2 is smaller than the distance between the first electrode 610 and the second electrode 630 in the third pixel region P3 that emits light in the third wavelength range (red) longer than the second wavelength range. Therefore, the light emitting efficiency of the organic light emitting diode D5 is improved.

[0229] 16, the first auxiliary hole transport layer 662a is formed in the first pixel region P1, but the microcavity structure can be realized without the first auxiliary hole transport layer 662a. In addition, a capping layer (not shown) can be further formed on the second electrode 630 to improve light extraction.

[0230] The light emitting material layer 640 includes a first light emitting material layer 642 located in the first pixel region P1, a second light emitting material layer 644 located in the second pixel region P2, and a third light emitting material layer 646 located in the third pixel region P3. The first light emitting material layer 642, the second light emitting material layer 644, and the third light emitting material layer 646 may be a blue light emitting material layer, a green light emitting material layer, and a red light emitting material layer, respectively.

[0231] The first light emitting material layer 642 of the first pixel region P1 may include a first compound DF which is a delayed fluorescent material having the structure of chemical formulas (1) to (6), a second compound FD which is a fluorescent material having the structure of chemical formulas (7) to (9), and optionally a third compound H which may be a host. The first light emitting material layer 642 may be a single layer, a two-layer (see FIG. 8), or a three-layer (see FIG. 11).

[0232] At this time, the content of the third compound H may be greater than the content of the first compound DF, and the content of the first compound DF may be greater than the content of the second compound FD in the first light emitting material layer 642. When the content of the first compound DF is greater than the content of the second compound FD, energy can be sufficiently transferred from the first compound DF to the second compound FD.

[0233] The second light emitting material layer 644 in the second pixel region P2 may include a host and a green dopant, and the third light emitting material layer 646 in the third pixel region P3 may include a host and a red dopant. For example, the host of the second light emitting material layer 644 and the third light emitting material layer 646 may include a third compound H, and the green dopant and the red dopant may include at least one of a green or red phosphorescent material, a green or red fluorescent material, and a green or red delayed fluorescent material, respectively.

[0234] 16 emits blue light, green light and red light in the first to third pixel regions P1, P2 and P3, respectively, so that the organic light emitting display device 500 (see FIG. 15) can realize color images.

[0235] Meanwhile, in order to improve color purity, the organic light emitting display device 500 may further include color filter layers corresponding to the first to third pixel regions P1, P2, and P3. For example, the color filter layers may include a first color filter layer (blue color filter layer) corresponding to the first pixel region P1, a second color filter layer (green color filter layer) corresponding to the second pixel region P2, and a third color filter layer (red color filter layer) corresponding to the third pixel region P3.

[0236] When the organic light emitting display device 500 is a bottom emission type, the color filter layer may be located between the organic light emitting diode D and the substrate 510. When the organic light emitting display device 500 is a top emission type, the color filter layer may be located on the organic light emitting diode D.

[0237] Fig. 17 is a cross-sectional view showing an organic light emitting display device according to a third embodiment of the present invention. As shown in Fig. 17, the organic light emitting display device 1000 includes a substrate 1010 in which first to third pixel regions P1, P2, and P3 are formed, 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, and 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.

[0238] 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. The thin-film transistor Tr is located on the substrate 1010, but a buffer layer (not shown) may be formed on the substrate 1010, and the thin-film transistor Tr may be formed thereon. As described with reference to FIG. 2, the thin-film transistor Tr includes a semiconductor layer, a gate electrode, a source electrode, and a drain electrode, and serves as a driving element.

[0239] A color filter layer 1020 is located on the substrate 1010. As an example, the color filter layer 1020 may include a first color filter layer 1022 corresponding to the first pixel region P1, a second color filter layer 1024 corresponding to the second pixel region P2, and a third color filter layer 1026 corresponding to the third pixel region 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.

[0240] A planarization layer 1050 is located on the thin film transistor Tr and the color filter layer 1020. The planarization 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.

[0241] 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 also includes a first electrode 1110 connected to the drain electrode of the thin film transistor Tr, a light emitting layer 1120 and a second electrode 1130 which are sequentially stacked on the first electrode 1110. The organic light emitting diode D emits white light in the first to third pixel regions P1, P2, and P3.

[0242] The first electrode 1110 is formed separately for each of the first to third pixel regions P1, P2, and P3, and the second electrode 1130 is formed integrally corresponding to the first to third pixel regions P1, P2, and P3. The first electrode 1110 may be one of an anode and a cathode, and the second electrode 1130 may be the other. In addition, the first electrode 1110 may be a transmissive electrode, and the second electrode 1130 may be a reflective electrode.

[0243] For example, the first electrode 1110 is an anode and may include a transparent conductive oxide layer made of a conductive material having a relatively large work function, such as a transparent conductive oxide (TCO). The second electrode 1130 is a cathode and may include a metal material layer made of a conductive material having a relatively small work function, such as 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, or an alloy thereof (e.g., an Mg-Ag alloy), or a combination thereof.

[0244] The light emitting layer 1120 is formed on the first electrode 1110 and includes at least two light emitting portions emitting different colors. Each of the light emitting portions may have a single layer structure of an emissive material layer (EML). Alternatively, each of the light emitting portions 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). The light emitting layer 1120 may further include a charge generation layer (CGL) located between the light emitting portions.

[0245] In this case, at least one of the two or more light-emitting parts may include a first compound DF, which is a delayed fluorescent material having the structure of one of the chemical formulas (1) to (6), a second compound FD, which is a fluorescent material having the structure of one of the chemical formulas (7) to (9), and may optionally include a third compound H, which may be a host.

[0246] A bank layer 1060 is formed on the planarization layer 1050 to cover the end of the first electrode 1110. The bank layer 1060 corresponds to the first to third pixel regions P1, P2, and P3, respectively, and exposes the center of the first electrode 1110. As described above, since the organic light emitting diode D emits white light in the first to third pixel regions P1, P2, and P3, the light emitting layer 1120 does not need to be formed separately for each of the first to third pixel regions P1, P2, and P3, and can be formed as a common layer. The bank layer 1060 is formed to prevent current leakage at the end of the first electrode 1110, but may be omitted.

[0247] Although not shown in the drawings, the OLED display 1000 may further include a moisture barrier film on the second electrode 1130 to prevent external moisture from penetrating into the OLED D. In addition, the OLED display 1000 may further include a polarizer under the substrate 1010 to reduce reflection of external light.

[0248] 17, 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 emission type. Alternatively, in the organic light emitting display device 1000, the first electrode 1110 may be a reflective electrode, the second electrode 1130 may be a transmissive electrode (semi-transmissive electrode), and the color filter layer 1020 may be located above the organic light emitting diode D.

[0249] In the organic light-emitting display device 1000, the organic light-emitting diodes D in the first to third pixel regions P1, P2, and P3 emit white light, which passes through the first to third color filter layers 1022, 1024, and 1026, thereby displaying blue, green, and red in the first to third pixel regions P1, P2, and P3, respectively.

[0250] Although not shown in the figure, a color conversion layer may be provided between the organic light emitting diode D and the color filter layer 1020. The color conversion layer includes a blue color conversion layer, a green color conversion layer, and a red color conversion layer corresponding to the first to third pixel regions P1, P2, and P3, respectively, 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. This can further improve the color purity of the organic light emitting display device 1000. Alternatively, a color conversion layer may be included instead of the color filter layer 1020.

[0251] 18 is a cross-sectional view illustrating an organic light-emitting diode according to a sixth exemplary embodiment of the present invention. As shown in FIG. 18, the organic light-emitting diode D6 includes a first electrode 1110 and a second electrode 1130 facing each other, and an emitting layer 1120 located between the first electrode 1110 and the second electrode 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.

[0252] The light emitting layer 1120 includes a first light emitting unit 1220 including a first light emitting material layer 1240 (lower light emitting material layer), a second light emitting unit 1320 including a second light emitting material layer 1340 (middle light emitting material layer), and a third light emitting unit 1420 including a third light emitting material layer 1440 (upper light emitting material layer). The light emitting layer 1120 may further include a first charge generation layer 1280 located between the first light emitting unit 1220 and the second light emitting unit 1320, and a second charge generation layer 1380 located between the second light emitting unit 1320 and the third light emitting unit 1420. Thus, the first light emitting unit 1220, the first charge generation layer 1280, the second light emitting unit 1320, the second charge generation layer 1380, and the third light emitting unit 1420 are sequentially stacked on the first electrode 1110.

[0253] The first light emitting unit 1220 may include at least one of a hole injection layer 1250 (HIL) located between the first electrode 1110 and the first light emitting material layer 1240, a first hole transport layer 1260 (HTL1) located between the first light emitting material layer 1240 and the hole injection layer 1250, and a first electron transport layer 1270 (ETL1) located between the first light emitting material layer 1240 and the first charge generation layer 1280. In some cases, the first light emitting unit 1220 may further include at least one of a first electron blocking layer 1265 (EBL1) located between the first hole transport layer 1260 and the first light emitting material layer 1240, and a first hole blocking layer 1275 (HBL1) located between the first light emitting material layer 1240 and the first electron transport layer 1270.

[0254] The second light emitting unit 1320 may include at least one of a second hole transport layer 1360 (HTL2) located between the first charge generating layer 1280 and the second light emitting material layer 1340, and a second electron transport layer 1370 (ETL2) located between the second light emitting material layer 1340 and the second charge generating layer 1380. In some cases, the second light emitting unit 1320 may further include at least one of a second electron blocking layer 1365 (EBL2) located between the second hole transport layer 1360 and the second light emitting material layer 1340, and a second hole blocking layer 1375 (HBL2) located between the second light emitting material layer 1340 and the second electron transport layer 1370.

[0255] The third light emitting unit 1420 may include at least one of a third hole transport layer 1460 (HTL3) located between the second charge generating layer 1380 and the third light emitting material layer 1440, a third electron transport layer 1470 (ETL3) located between the third light emitting material layer 1440 and the second electrode 1130, and an electron injection layer 1480 (EIL) located between the third electron transport layer 1470 and the second electrode 1130. In some cases, the third light emitting unit 1420 may further include at least one of a third electron blocking layer 1465 (EBL3) located between the third hole transport layer 1460 and the third light emitting material layer 1440, and a third hole blocking layer 1475 (HBL3) located between the third light emitting material layer 1440 and the third electron transport layer 1470.

[0256] The first charge generation layer 1280 is located between the first light emitting unit 1220 and the second light emitting unit 1320. In other words, the first light emitting unit 1220 and the second light emitting unit 1320 are connected via the first charge generation layer 1280. The first charge generation layer 1280 may be a PN type in which a first N-type charge generation layer 1282 and a first P-type charge generation layer 1284 are joined together.

[0257] 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 section 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 section 1320.

[0258] The second charge generation layer 1380 is located between the second light emitting unit 1320 and the third light emitting unit 1420. In other words, the second light emitting unit 1320 and the third light emitting unit 1420 are connected via the second charge generation layer 1380. The second charge generation layer 1380 may be a PN type in which a second N-type charge generation layer 1382 and a second P-type charge generation layer 1384 are joined together.

[0259] 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 section 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 section 1420.

[0260] In this embodiment, one of the first to third light emitting material layers 1240, 1340, 1440 may be a blue light emitting material layer, another of the first to third light emitting material layers 1240, 1340, 1440 may be a green light emitting material layer, and the remaining one of the first to third light emitting material layers 1240, 1340, 1440 may be a red light emitting material layer.

[0261] 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. In the following, a case in which 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 1340 is a red light emitting material layer will be described.

[0262] The first luminescent material layer 1240 includes a first compound DF which is a delayed fluorescent material having the structure of chemical formulas (1) to (6), a second compound FD which is a fluorescent material having the structure of chemical formulas (7) to (9), and may optionally include a third compound H which may be a host. The first luminescent material layer 1240 including the first compound to the third compound may be a single layer, a two-layer (see FIG. 8), or a three-layer (see FIG. 11).

[0263] The content of the third compound H in the first light-emitting material layer 1240 may be greater than the content of the first compound DF, and the content of the first compound DF may be greater than the content of the second compound FD. When the content of the first compound DF is greater than the content of the second compound FD, energy can be sufficiently transferred from the first compound DF to the second compound FD.

[0264] The second emissive layer 1340 may include a host and a green dopant, and the third emissive layer 1440 may include a host and a red dopant. For example, in each of the second emissive layer 1340 and the third emissive layer 1440, the host may include a third compound H, and the green and red dopants may include at least one of green and red phosphorescent materials, green and red fluorescent materials, and green and red delayed fluorescent materials, respectively.

[0265] The organic light emitting diode D6 emits white light in the first to third pixel regions P1, P2, P3 (see FIG. 16), and the white light passes through a color filter layer 1020 (see FIG. 17) formed corresponding to the first to third pixel regions P1, P2, P3. This allows the organic light emitting display device 1000 (see FIG. 17) to realize a full-color image.

[0266] 19 is a cross-sectional view showing an organic light-emitting diode according to a seventh exemplary embodiment of the present invention. As shown in FIG. 19, the organic light-emitting diode D7 includes a first electrode 1110 and a second electrode 1130 facing each other, and a light-emitting layer 1120A located between the first electrode 1110 and the second electrode 1130.

[0267] The first electrode 1110 can be an anode and the second electrode 1130 can be a cathode. For example, the first electrode 1110 can be a transmissive electrode and the second electrode 1130 can be a reflective electrode.

[0268] The light emitting layer 1120A includes a first light emitting portion 1520 including a first light emitting material layer 1540 (lower light emitting material layer), a second light emitting portion 1620 including a second light emitting material layer 1640 (middle light emitting material layer), and a third light emitting portion 1720 including a third light emitting material layer 1740 (upper light emitting material layer). The light emitting layer 1120A may further include a first charge generation layer 1580 located between the first light emitting portion 1520 and the second light emitting portion 1620, and a second charge generation layer 1680 located between the second light emitting portion 1620 and the third light emitting portion 1720. Thus, the first light emitting portion 1520, the first charge generation layer 1580, the second light emitting portion 1620, the second charge generation layer 1680, and the third light emitting portion 1720 are sequentially stacked on the first electrode 1110.

[0269] The first light emitting unit 1520 may include at least one of a hole injection layer 1550 (HIL) located between the first electrode 1110 and the first light emitting material layer 1540, a first hole transport layer 1560 (HTL1) located between the first light emitting material layer 1540 and the hole injection layer 1550, and a first electron transport layer 1570 (ETL1) located between the first light emitting material layer 1540 and the first charge generation layer 1580. Optionally, the first light emitting unit 1520 may further include at least one of a first electron blocking layer 1565 (EBL1) located between the first hole transport layer 1560 and the first light emitting material layer 1540, and a first hole blocking layer 1575 (HBL1) located between the first light emitting material layer 1540 and the first electron transport layer 1570.

[0270] The second light emitting layer 1640 constituting the second light emitting unit 1620 includes a middle lower light emitting material layer 1642 (first layer) and a middle upper light emitting material layer 1644 (second layer). That is, the middle lower light emitting material layer 1642 is located adjacent to the first electrode 1110, and the middle upper light emitting material layer 1644 is located adjacent to the second electrode 1130. In addition, the second light emitting unit 1620 may include at least one of a second hole transport layer 1660 (HTL2) located between the first charge generating layer 1580 and the second light emitting material layer 1640, and a second electron transport layer 1670 (ETL2) located between the second light emitting material layer 1640 and the second charge generating layer 1680. Optionally, the second light-emitting section 1620 may further include at least one of a second electron blocking layer 1665 (EBL2) located between the second hole transport layer 1660 and the second light-emitting material layer 1640, and a second hole blocking layer 1675 (HBL2) located between the second light-emitting material layer 1640 and the second electron transport layer 1670.

[0271] The third light emitting unit 1720 may include at least one of a third hole transport layer 1760 (HTL3) located between the second charge generating layer 1680 and the third light emitting material layer 1740, a third electron transport layer 1770 (ETL3) located between the third light emitting material layer 1740 and the second electrode 1130, and an electron injection layer 1780 (EIL) located between the third electron transport layer 1770 and the second electrode 1130. Optionally, the third light emitting unit 1720 may further include at least one of a third electron blocking layer 1765 (EBL3) located between the third hole transport layer 1760 and the third light emitting material layer 1740, and a third hole blocking layer 1775 (HBL3) located between the third light emitting material layer 1740 and the third electron transport layer 1770.

[0272] The first charge generation layer 1580 is located between the first light emitting section 1520 and the second light emitting section 1620. In other words, the first light emitting section 1520 and the second light emitting section 1620 are connected through the first charge generation layer 1580. The first charge generation layer 1580 may be a PN type in which a first N-type charge generation layer 1582 and a first P-type charge generation layer 1584 are joined together. 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.

[0273] The second charge generation layer 1680 is located between the second light emitting section 1620 and the third light emitting section 1720. In other words, the second light emitting section 1620 and the third light emitting section 1720 are connected through the second charge generation layer 1680. The second charge generation layer 1680 may be a PN type in which a second N-type charge generation layer 1682 and a second P-type charge generation layer 1684 are joined together. 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.

[0274] In this embodiment, the first light-emitting material layer 1540 and the third light-emitting material layer 1740 may each be a blue light-emitting material layer. For example, the first light-emitting material layer 1540 and the third light-emitting material layer 1740 may include a first compound DF, which is a delayed fluorescent material having the structure of chemical formulas (1) to (6), a second compound FD, which is a fluorescent material having the structure of chemical formulas (7) to (9), and may optionally include a third compound H, which may be a host. The first compound DF, the second compound FD, and the third compound H constituting the first light-emitting material layer 1540 and the third light-emitting material layer 1740 may be the same or different. In some cases, the third light-emitting material layer 1740 may include a compound different from at least one of the first compound DF and the second compound FD contained in the first light-emitting material layer 1540, and may emit light of a different wavelength or have a different luminous efficiency from the first light-emitting material layer 1540.

[0275] For example, when the first luminescent material layer 1540 and the third luminescent material layer 1740 include a first compound DF, a second compound FD, and a third compound H, the content of the third compound H in each of the first luminescent material layer 1540 and the third luminescent material layer 1740 may be greater than the content of the first compound DF, and the content of the first compound DF may be greater than the content of the second compound FD. When the content of the first compound DF is greater than the content of the second compound FD, energy can be sufficiently transferred from the first compound DF to the second compound FD.

[0276] One of the intermediate lower luminescent material layer 1642 (first layer) and the intermediate upper luminescent material layer 1644 (second layer) constituting the second luminescent material layer 1640 may be a green luminescent material layer and the other may be a red luminescent material layer. That is, the green luminescent material layer and the red luminescent material layer are stacked in succession to form the second luminescent material layer 1640.

[0277] For example, the middle lower luminescent material layer 1642, which is a red luminescent material layer, may include a host and a red dopant, and the middle upper luminescent material layer 1644, which is a green luminescent material layer, may include a host and a green dopant. As an example, the host may include a third compound H, and the red and green dopants may include at least one of red and green phosphorescent materials, red and green fluorescent materials, and red and green delayed fluorescent materials, respectively.

[0278] The organic light emitting diode D7 emits white light in the first to third pixel regions P1, P2, and P3 (see FIG. 15), and the white light passes through the color filter layer 1020 (see FIG. 17) in each of the first to third pixel regions P1, P2, and P3. This allows the organic light emitting display device 1000 (see FIG. 17) to realize a full-color image.

[0279] In FIG. 19, organic light emitting diode D7 includes first light emitting material layer 1540 and third light emitting material layer 1740, which are blue light emitting material layers, and has a triple stack structure including first to third light emitting units 1520, 1620, and 1720. However, either one of first light emitting unit 1520 including first light emitting material layer 1540 and third light emitting unit 1720 including third light emitting material layer 1740 may be omitted to have a double stack structure.

[0280] Hereinafter, the present invention will be described using exemplary embodiments, but the present invention is not limited to the technical ideas described in the following examples.

[0281] Example 1 (Ex.1): Manufacture of organic light-emitting diode An organic light-emitting diode was manufactured including the compound 1-1 (HOMO: -5.6 eV, LUMO: -2.9 eV) of formula (6) as the first compound DF of the light-emitting material layer, the compound 2-1 (HOMO: -5.6 eV, LUMO: -2.9 eV) of formula (9) as the second compound FD, and mCBP (HOMO: -6.0 eV, LUMO: -2.5 eV) as the third compound H.

[0282] The ITO substrate was cleaned with UV ozone before use and placed in the evaporation system. It was then transferred into the deposition chamber for deposition and was heated for about 10 min. -7 The organic layers were evaporated from a heated boat under a vacuum of Torr on top of the substrate in the following order: The evaporation rate of the organics was set to 1 Å / s.

[0283] Anode (ITO, 50 nm), hole injection layer (HAT-CN, 7 nm), hole transport layer (NPB, 45 nm), electron blocking layer (TAPC, 10 nm), light emitting material layer (mCBP: compound 1-1: compound 2-1 = 69:30:1 weight ratio, 30 nm), hole blocking layer (B3PYMPM, 10 nm), electron blocking layer (TPBi, 30 nm), electron injection layer (LiF), cathode (Al).

[0284] After the CPL (capping layer) was deposited, it was sealed with glass. After the emissive layer and cathode were evaporated, it was transferred from the deposition chamber to a dry box to form the coating, and then sealed using a UV-cured epoxy and a moisture getter. The structures of the organic compounds used in the emissive layer are shown below.

[0285] [ka]

[0286] Example 2 (Ex.2): Manufacture of organic light-emitting diode An organic light-emitting diode was manufactured using the same materials as in Example 1, except that compound 1-13 (HOMO: -5.5 eV, LUMO: -2.8 eV) of chemical formula (6) was used instead of compound 1-1 as the first compound of the light-emitting material layer.

[0287] Example 3 (Ex.3): Manufacture of organic light-emitting diode An organic light-emitting diode was manufactured using the same materials as in Example 1, except that compound 2-20 (HOMO: -5.4 eV, LUMO: -2.8 eV) of chemical formula (9) was used instead of compound 2-1 as the second compound of the light-emitting material layer.

[0288] Example 4 (Ex.4): Manufacture of organic light-emitting diode An organic light-emitting diode was manufactured using the same materials as in Example 1, except that compound 1-13 (HOMO: -5.5 eV, LUMO: -2.8 eV) of chemical formula (6) was used as the first compound in the light-emitting layer instead of compound 1-1, and compound 2-20 was used as the second compound in the light-emitting layer instead of compound 2-1.

[0289] Example 5 (Ex.5): Fabrication of organic light-emitting diode An organic light-emitting diode was manufactured using the same materials as in Example 1, except that compound 1-8 (HOMO: -5.5 eV, LUMO: -2.9 eV) of chemical formula (6) was used instead of compound 1-1 as the first compound of the light-emitting material layer.

[0290] Example 6 (Ex.6): Manufacture of organic light-emitting diode An organic light-emitting diode was manufactured using the same materials as in Example 1, except that compound 1-9 (HOMO: -5.6 eV, LUMO: -2.8 eV) of chemical formula (6) was used instead of compound 1-1 as the first compound of the light-emitting material layer.

[0291] Example 7 (Ex.7): Fabrication of organic light-emitting diode An organic light-emitting diode was manufactured using the same materials as in Example 1, except that compound 1-8 of chemical formula (6) was used instead of compound 1-1 as the first compound in the light-emitting material layer, and compound 2-20 of chemical formula (9) was used instead of compound 2-1 as the second compound in the light-emitting material layer.

[0292] Example 8 (Ex.8): Manufacture of organic light-emitting diode An organic light-emitting diode was manufactured using the same materials as in Example 6, except that compound 1-9 of chemical formula (6) was used instead of compound 1-1 as the first compound in the light-emitting layer, and compound 2-20 was used instead of compound 2-1 as the second compound in the light-emitting layer.

[0293] Example 9 (Ex. 9): Manufacture of organic light-emitting diode An organic light emitting diode was fabricated using the same materials as in Example 1, except that the luminescent material layer did not contain the second compound, but instead mixed mCBP and compound 1-1 in a weight ratio of 70:30.

[0294] Examples 10 to 12 (Ex. 10 to 12): Production of organic light-emitting diodes Organic light-emitting diodes were manufactured using the same materials as in Example 9, except that the luminescent material layer did not contain the second compound and compound 1-13 (Example 10), compound 1-8 (Example 11), and compound 1-9 (Example 12) were used instead of compound 1-1, respectively.

[0295] Comparative Examples 1 to 5 (Ref. 1 to 5): Manufacturing of organic light-emitting diodes The luminescent material layer did not contain the second compound, and mCBP and the following comparative compound 1-1 (HOMO: -5.2 eV, LUMO: -1.9 eV) were mixed in a weight ratio of 80:20 (Comparative Example 1), mCBP and the following comparative compound 1-2 (HOMO: -5.2 eV, LUMO: -1.9 eV) were mixed in a weight ratio of 80:20 (Comparative Example 2), and mCBP and the following comparative compound 1-3 (HOMO: -5.1 eV, LUMO: -1.9 eV) were mixed in a weight ratio of 80:20 (Comparative Example 3). Organic light-emitting diodes were manufactured using the same materials as in Example 1, except that mCBP and comparative compound 1-4 (HOMO: -5.2 eV, LUMO: -1.9 eV) were mixed in a weight ratio of 80:20 (Comparative Example 3), mCBP and comparative compound 1-4 (HOMO: -5.2 eV, LUMO: -1.9 eV) were mixed in a weight ratio of 80:20 (Comparative Example 4), and mCBP and comparative compound 1-5 (HOMO: -5.5 eV, LUMO: -2.7 eV) were mixed in a weight ratio of 80:20 (Comparative Example 5).

[0296] Comparative Example 6 (Ref. 6): Fabrication of Organic Light-Emitting Diodes An organic light emitting diode was manufactured using the same materials as in Example 1, except that the following comparative compound 1-5 was used instead of compound 1-1 as the first compound of the light emitting material layer.

[0297] Comparative Example 7 (Ref. 7): Fabrication of Organic Light-Emitting Diodes An organic light emitting diode was manufactured using the same materials as in Example 1, except that the following comparative compound 2-1 (HOMO: -5.2 eV, LUMO: -2.7 eV) was used instead of compound 2-1 as the second compound of the light emitting material layer.

[0298] Comparative Example 8 (Ref. 8): Fabrication of Organic Light-Emitting Diodes An organic light emitting diode was manufactured using the same materials as in Example 1, except that the following comparative compound 2-2 (HOMO: -5.2 eV, LUMO: -2.6 eV) was used instead of compound 2-1 as the second compound of the light emitting material layer.

[0299] Comparative Example 9 (Ref. 9): Fabrication of Organic Light-Emitting Diodes An organic light-emitting diode was manufactured using the same materials as in Example 1, except that compound 1-13 of chemical formula (6) was used instead of compound 1-1 as the first compound in the light-emitting layer, and comparative compound 2-1 was used instead of compound 2-1 as the second compound in the light-emitting layer.

[0300] Comparative Example 10 (Ref. 10): Fabrication of organic light-emitting diodes An organic light-emitting diode was manufactured using the same materials as in Example 1, except that compound 1-13 of chemical formula (6) was used instead of compound 1-1 as the first compound in the light-emitting layer, and comparative compound 2-2 was used instead of compound 2-1 as the second compound in the light-emitting layer.

[0301] Comparative Example 11 (Ref. 11): Fabrication of organic light-emitting diodes An organic light emitting diode was manufactured using the same materials as in Example 1, except that the following comparative compound 1-6 (HOMO: -5.9 eV, LUMO: -2.8 eV) was used instead of compound 1-1 as the first compound of the light emitting material layer.

[0302] Comparative Example 12 (Ref. 12): Fabrication of organic light-emitting diodes An organic light-emitting diode was manufactured using the same materials as in Example 1, except that the following comparative compound 1-6 was used instead of compound 1-1 as the first compound in the light-emitting layer, and 2-20 of chemical formula (9) was used instead of compound 2-1 as the second compound in the light-emitting layer.

[0303] Comparative Example 13 (Ref. 13): Fabrication of organic light-emitting diodes An organic light-emitting diode was manufactured using the same materials as in Example 1, except that the following comparative compound 1-6 was used instead of compound 1-1 as the first compound in the light-emitting layer, and the following comparative compound 2-1 was used instead of compound 2-1 as the second compound in the light-emitting layer.

[0304] Comparative Example 14 (Ref. 14): Fabrication of organic light-emitting diodes An organic light-emitting diode was manufactured using the same materials as in Example 1, except that the following comparative compound 1-6 was used instead of compound 1-1 as the first compound in the light-emitting layer, and the following comparative compound 2-2 was used instead of compound 2-1 as the second compound in the light-emitting layer.

[0305] Comparative Compound [ka]

[0306] The bond dissociation energy (BOE) between the electron acceptor moiety and the electron donor moiety was evaluated in the neutral state, anionic state, cationic state, negative charge state, and positive charge state for compound 1-1 used as the first compound in Example 1 (the boron ring moiety of the electron acceptor and the condensed carbazole moiety of the electron donor are bonded by a C-C bond) and comparative compound 1-5 used as the first compound in Comparative Example 5 (the boron ring moiety of the electron acceptor and the condensed carbazole moiety of the electron donor are bonded by a C-N bond). The results are shown in Table 1 below. It can be seen that the bond dissociation energy of compound 1-1 is higher.

[0307] [Table 1]

[0308] Tables 2 and 3 below show the HOMO energy levels of the first and second compounds used in Examples 1 to 12 and Comparative Examples 1 to 14, respectively, and the HOMO energy band gaps (ΔHOMO) between the first and second compounds.

[0309] [Table 2]

[0310] [Table 3]

[0311] Experimental example 1: Measurement of the light-emitting characteristics of an organic light-emitting diode The optical characteristics of the organic light-emitting diodes manufactured in Examples 1 to 12 and Comparative Examples 1 to 14 were measured. 2 Each organic light-emitting diode with an emission area of ​​8.6 mA / cm was connected to an external power supply, and the device characteristics were evaluated at room temperature using a current source (KEITHLEY) and a photometer (PR650). 2 At a current density of 1000 mA, the driving voltage (V), current efficiency (cd / A), color coordinate (CIEy), external quantum efficiency (EQE, %), and LT 95 The luminance (time required for the luminance to decrease by 95% from the initial luminance, relative value), and the presence or absence of hole traps and exciton complexes (Y if hole traps and / or exciton complexes were formed, and N if hole traps and / or exciton complexes were not formed) were measured. The luminance characteristics of the organic light-emitting diodes manufactured in Examples 1 to 12 and Comparative Examples 1 to 14 are shown in Tables 4 and 5, respectively.

[0312] [Table 4]

[0313] [Table 5]

[0314] As shown in Tables 4 and 5, the electron donor moiety and electron acceptor moiety of the first compound formed a carbon-carbon bond, and the HOMO energy band gap of the first compound and the second compound was set to less than 0.3 eV, and the LUMO energy band gap of the first compound and the second compound was set to less than 0.3 eV, so that the light-emitting characteristics of the organic light-emitting diode were significantly improved. In particular, compared with the case where a compound in which the electron donor moiety and electron acceptor moiety of the first compound formed a carbon-nitrogen bond was used alone (Comparative Examples 1 to 5), the current efficiency, EQE, and luminescence lifetime did not increase significantly, or rather decreased significantly, when the first compound was used in combination with the second compound (Comparative Examples 6 to 14).

[0315] On the other hand, when the first compound was used in combination with the second compound (Examples 1 to 8), the current efficiency, EQE, and luminescence lifetime were significantly increased compared to when the compound in which the electron donor moiety and the electron acceptor moiety of the first compound formed a carbon-carbon bond was used alone (Examples 9 to 12).

[0316] Hole trapping occurred when the HOMO energy band gap between the first compound and the second compound was 0.3 eV or more as in Comparative Examples 9 to 14. Furthermore, when the HOMO energy band gap and the LUMO energy band gap between the first compound and the second compound were both 0.3 eV or more or the HOMO energy band gap was 0.5 eV or more as in Comparative Examples 8, 13, and 14, an excited complex was formed between the first compound and the second compound.

[0317] Compared with the organic light-emitting diodes manufactured in Comparative Examples 6 to 14, the driving voltage of the organic light-emitting diodes manufactured in Examples 1 to 8 was reduced by up to 18.3%, while the current efficiency, EQE, and luminous lifetime were improved by up to 138.2%, 96.2%, and 58.8 times, respectively.

[0318] The present invention has been described above based on exemplary embodiments and examples of the present invention, but the present invention is not limited to the technical ideas described in the above-mentioned embodiments and examples. Rather, a person having ordinary knowledge in the technical field to which the present invention belongs can easily devise various modifications and changes based on the above-mentioned embodiments and examples. Furthermore, it is clear from the claims that all such modifications and changes fall within the scope of the present invention.

Claims

1. A first electrode; a second electrode facing the first electrode; a light emitting layer located between the first electrode and the second electrode, the light emitting layer including at least one light emitting material layer; the at least one emissive material layer comprises a first compound and a second compound; The first compound includes an organic compound having a structure represented by the following chemical formula (1): The second compound includes an organic compound having a structure represented by the following chemical formula (8A) or (8B): The highest occupied molecular orbital (HOMO) energy level of the first compound ＤＦ ) and the HOMO energy level of the second compound (HOMO ＦＤ ) is an organic light-emitting diode that satisfies the following formula (I): │HOMO ＦＤ -HOMO ＤＦ │<0.3eV…(I) [Formula 1] (In chemical formula (1), R １ and R ２ are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, or a substituted or unsubstituted C １ ~C ２０ an alkyl group of the formula: １ ~C ２０ an alkylamino group of the formula １ ~C ２０ an alkylsilyl group of the formula ６ ~C ３０ or a substituted or unsubstituted C ３ ~C ３０ When a is plural, each R １ may be the same or different, and when b is plural, each R ２ Optionally, when a and b are each plural, two adjacent R １ , and / or two adjacent R ２are bonded to each other, and each is a substituted or unsubstituted C ６ ~C ２０ or a substituted or unsubstituted C ３ ~C ２０ D includes a moiety having the structure of the following chemical formula (5): [chemical 2] (In chemical formula (5), R １３ is a substituted or unsubstituted C ６ ~C ３０ aryl groups of the formula ３ ~C ３０ R is a heteroaryl group of the formula: １４ and R １５ are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, or a substituted or unsubstituted C １ ~C ２０ an alkyl group of the formula: １ ~C ２０ an alkylamino group of the formula ６ ~C ３０ or a substituted or unsubstituted C ３ ~C ３０ When m is a multiple number, each R １４ may be the same or different, and when n is a plurality of R １５ Optionally, when m and n are each plural, two adjacent R １４ and / or at least two adjacent R １５ are bonded to each other, and each is a substituted or unsubstituted C ６ ~C ２０ or a substituted or unsubstituted C ３ ~C ２０ m is an integer from 0 to 3, n is an integer from 0 to 4, and the asterisk indicates the attachment site. [C3] [C4] (In chemical formulas (8A) and (8B), R ２１ , R ２５ ~R ２８ , R ３１ ~R ３４ are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, or a substituted or unsubstituted C １ ~C ２０ an alkyl group of the formula: １ ~C ２０ an alkylsilyl group of the formula １ ~C ２０ an alkylamino group of the formula ６ ~C ３０ aryl groups of the formula ３ ~C ３０ is a heteroaryl group of the formula:

2. A first electrode; a second electrode facing the first electrode; a light emitting layer located between the first electrode and the second electrode, the light emitting layer including at least one light emitting material layer; the at least one emissive material layer comprises a first compound and a second compound; The first compound includes an organic compound having a structure represented by the following chemical formula (1): The second compound includes an organic compound having a structure represented by the following chemical formula (8A) or (8B): The organic light emitting diode, wherein the lowest unoccupied molecular orbital (LUMO) energy level of the first compound is shallower than or equal to the LUMO energy level of the second compound. [C5] (In chemical formula (1), R １ and R ２ are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, or a substituted or unsubstituted C １ ~C ２０ an alkyl group of the formula: １ ~C ２０ an alkylamino group of the formula １ ~C ２０ an alkylsilyl group of the formula ６~C ３０ or a substituted or unsubstituted C ３ ~C ３０ When a is plural, each R １ may be the same or different, and when b is plural, each R ２ Optionally, when a and b are each plural, two adjacent R １ , and / or two adjacent R ２ are bonded to each other, and each is a substituted or unsubstituted C ６ ~C ２０ or a substituted or unsubstituted C ３ ~C ２０ D includes a moiety having the structure of the following chemical formula (5): [C6] (In chemical formula (5), R １３ is a substituted or unsubstituted C ６ ~C ３０ aryl groups of the formula ３ ~C ３０ R is a heteroaryl group of the formula: １４ and R １５ are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, or a substituted or unsubstituted C １ ~C ２０ an alkyl group of the formula: １ ~C ２０ an alkylamino group of the formula ６ ~C ３０ or a substituted or unsubstituted C ３ ~C ３０ When m is a multiple number, each R １４ may be the same or different, and when n is a plurality of R １５ Optionally, when m and n are each plural, two adjacent R １４ and / or at least two adjacent R １５ are bonded to each other, and each is a substituted or unsubstituted C ６ ~C ２０ or a substituted or unsubstituted C ３ ~C ２０ m is an integer from 0 to 3, n is an integer from 0 to 4, and the asterisk indicates the attachment site. [C7] [C8] (In chemical formulas (8A) and (8B), R ２１ , R ２５ ~R ２８ , R ３１ ~R ３４ are each independently a hydrogen atom, a deuterium atom, a tritium atom, a halogen atom, or a substituted or unsubstituted C １ ~C ２０ an alkyl group of the formula: １ ~C ２０ an alkylsilyl group of the formula １ ~C ２０ an alkylamino group of the formula ６ ~C ３０ aryl groups of the formula ３ ~C ３０ is a heteroaryl group of the formula:

3. 2. The organic light emitting diode of claim 1, wherein a Lowest Unoccupied Molecular Orbital (LUMO) energy level of the first compound is shallower than or equal to a LUMO energy level of the second compound.

4. 2. The organic light emitting diode of claim 1, wherein an energy band gap between a highest occupied molecular orbital (HOMO) energy level and a lowest unoccupied molecular orbital (LUMO) energy level of the first compound is 2.6 eV or more and 3.1 eV or less.

5. The R of the chemical formula (1) １ and the above R ２ The organic light-emitting diode of claim 1 , wherein each of is a hydrogen atom.

6. 2. The organic light-emitting diode of claim 1, wherein the first compound is selected from the following organic compounds: [C9] [C10]

7. 2. The organic light-emitting diode of claim 1, wherein the second compound is selected from the following organic compounds: [C11] [C12] [C13]

8. 10. The organic light emitting diode of claim 1, wherein the at least one luminescent material layer comprises a single-layer luminescent material layer.

9. The organic light-emitting diode according to claim 8 , wherein the single-layer luminescent material layer further comprises a third compound.

10. 10. The organic light-emitting diode of claim 9, wherein an excited triplet energy level of the third compound is higher than an excited triplet energy level of the first compound, and an excited triplet energy level of the first compound is higher than an excited triplet energy level of the second compound.

11. 10. The organic light-emitting diode of claim 9, wherein an excited singlet energy level of the third compound is higher than an excited singlet energy level of the first compound, and an excited singlet energy level of the first compound is higher than an excited singlet energy level of the second compound.

12. the at least one luminescent material layer includes a first luminescent material layer located between the first electrode and the second electrode, and a second luminescent material layer located between the first electrode and the first luminescent material layer or between the second electrode and the first luminescent material layer; the first light-emitting material layer includes the first compound, 2. The organic light emitting diode of claim 1, wherein the second luminescent material layer comprises the second compound.

13. 13. The organic light emitting diode of claim 12, wherein the first luminescent material layer further comprises a third compound, and the second luminescent material layer further comprises a fourth compound.

14. 14. The organic light-emitting diode of claim 13, wherein an excited triplet energy level of the third compound is higher than an excited triplet energy level of the first compound, and an excited triplet energy level of the first compound is higher than an excited triplet energy level of the second compound.

15. 14. The organic light-emitting diode of claim 13, wherein an excited singlet energy level of the third compound is higher than an excited singlet energy level of the first compound, and an excited singlet energy level of the first compound is higher than an excited singlet energy level of the second compound.

16. 14. The organic light emitting diode of claim 13, wherein an excited singlet energy level of the fourth compound is higher than an excited singlet energy level of the second compound.

17. 13. The organic light emitting diode of claim 12, wherein the at least one luminescent material layer further comprises a third luminescent material layer located on the opposite side of the second luminescent material layer with the first luminescent material layer interposed therebetween.

18. 20. The organic light emitting diode of claim 17, wherein the third luminescent material layer comprises a fifth compound and a sixth compound.

19. the light-emitting layer includes a first light-emitting portion located between the first electrode and the second electrode, a second light-emitting portion located between the first light-emitting portion and the second electrode, and a charge generating layer located between the first light-emitting portion and the second light-emitting portion, The organic light emitting diode of claim 1 , wherein at least one of the first light emitting portion and the second light emitting portion includes the at least one light emitting material layer.

20. The first light emitting portion includes the at least one light emitting material layer, The organic light emitting diode of claim 19 , wherein the second light emitting part emits light of at least one of red and green colors.

21. A substrate; An organic light emitting device comprising: an organic light emitting diode according to claim 1 located on the substrate.

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