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

Abstract

Disclosed is an organic light emitting diode (OLED) comprising at least one light emitting material (EML) disposed between two electrodes and a first light emitting material layer comprising a first compound and a second compound of a phosphorescent material and a second light emitting material layer comprising a third compound and a fourth compound having triplet state-triplet state annihilation properties, and an organic light emitting device comprising the OLED. Application of a light emitting material having adjusted excited singlet / triplet state energy levels, emission peak intensity and quarter peak full width to a light emitting material layer can reduce the driving voltage of the OLED and can improve the light emitting efficiency, blue light index and light emitting life of the OLED.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2021-0182140, filed in Korea on December 17, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to an organic light-emitting diode (OLED), and more specifically, to an OLED with excellent color purity and luminous lifetime, and an organic light-emitting device having the OLED. Background Technology

[0004] As display device sizes increase, there is a need for flat panel display devices that occupy less space. Among flat panel display devices, light-emitting displays utilizing organic light-emitting diodes (OLEDs) have attracted attention.

[0005] OLEDs can be formed with a thickness of less than The thin film, and the electrode configuration, can realize unidirectional or bidirectional images. Furthermore, OLEDs can be formed on flexible transparent substrates such as plastic substrates, allowing for easy realization of flexible or foldable displays. In addition, OLEDs have advantages over LCDs (liquid crystal displays), for example, OLEDs can be driven at lower voltages and have very high color purity.

[0006] In OLEDs, when charge is injected into the light-emitting material layer between the electron injection electrode (i.e., the cathode) and the hole injection electrode (i.e., the anode), the charge recombines to form excitons, which then emit light as they transition to a stable ground state.

[0007] Existing fluorescent materials suffer from low luminescence efficiency because their emission process involves only singlet excitons. In contrast, phosphorescent materials, in which both triplet and singlet excitons participate in the emission process, exhibit higher luminescence efficiency. However, the luminescence lifetime of metal complexes, representative phosphorescent materials, is too short for commercial applications. Specifically, blue phosphorescent materials, which have a longer triplet lifetime compared to blue fluorescent materials, exhibit a shorter luminescence lifetime with increasing triplet energy level. Therefore, blue phosphorescent materials with higher triplet energy levels used to induce deep blue light suffer from a reduced luminescence lifetime. Summary of the Invention

[0008] Therefore, embodiments of this disclosure relate to an OLED and an organic light-emitting device including the OLED, which substantially eliminates one or more problems caused by the limitations and disadvantages of the prior art.

[0009] One aspect of this disclosure is to provide an OLED with high color purity and improved luminous lifetime for inducing deep blue light, and an organic light-emitting device including the diode.

[0010] Additional features and aspects will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the inventive concept provided herein. Other features and aspects of the present disclosure concept may be realized and obtained by means of structures particularly emphasized in or derived therefrom in the written description, as well as the claims of this disclosure and the accompanying drawings.

[0011] To achieve these and other aspects of the present disclosure, as embodied and broadly described, an organic light-emitting diode (OLED) includes: a first electrode; a second electrode facing the first electrode; and a light-emitting layer disposed between the first electrode and the second electrode and including at least one light-emitting material layer, wherein the at least one light-emitting material layer includes a first light-emitting material layer and a second light-emitting material layer disposed adjacent to the first light-emitting material layer, wherein the first light-emitting material layer includes a first compound having a structure of Formula 1 and a second compound having a structure of Formula 3, and wherein the second light-emitting material layer includes a third compound having a structure of Formula 5 and a fourth compound having a structure of Formula 7.

[0012] [Formula 1]

[0013]

[0014] In Equation 1,

[0015] R 1 and R 2 Each is independently an unsubstituted or substituted carbazolyl or an unsubstituted or substituted carbazolinyl;

[0016] R 3 It is hydrogen, cyano, unsubstituted or substituted C1-C 20 Alkyl, unsubstituted or substituted C6-C 30 aryl, or unsubstituted or substituted C3-C 30 Mixed aromatics;

[0017] Z is N or CR 4 , where R 4 Hydrogen, unsubstituted or substituted C1-C 10 Alkyl, unsubstituted or substituted C6-C 30 aryl, or unsubstituted or substituted C3-C 30 heteroaryl; and

[0018] L 1 and L 2 Each is independently a single bond, unsubstituted or substituted C6-C30 Aryl styrene, or unsubstituted or substituted C3-C 30 Mixed aromatic base,

[0019] [Formula 3]

[0020]

[0021] In Equation 3,

[0022] R 11 To R 14 Each is independently hydrogen, halogen, cyano, unsubstituted or substituted C1-C 10 Alkyl, unsubstituted or substituted C1-C 10 Alkylamino, unsubstituted or substituted C6-C 30 Aryl, unsubstituted or substituted C3-C 30 Heteroaryl, or unsubstituted or substituted adamantyl,

[0023] [Formula 5]

[0024]

[0025] In Equation 5,

[0026] R 21 and R 22 Each is independently hydrogen, unsubstituted or substituted C1-C 20 Alkyl, unsubstituted or substituted C6-C 30 aryl, or unsubstituted or substituted C3-C 30 heteroaryl; and

[0027] R 23 and R 24 Each is independently unsubstituted or substituted C6-C 30 aryl, or unsubstituted or substituted C3-C 30 Mixed aromatics,

[0028] [Formula 7]

[0029]

[0030] In Equation 7,

[0031] R 31 To R 33 Each is independently hydrogen, halogen, cyano, unsubstituted or substituted C1-C 20 Alkyl, unsubstituted or substituted C6-C 30 Aryl, unsubstituted or substituted C3-C 30 heteroaryl, or unsubstituted or substituted C6-C 30 arylamino;

[0032] R 34 and R 35 Each is independently halogenated, cyano, unsubstituted or substituted C1-C. 20 Alkyl, unsubstituted or substituted C6-C 30 Aryl, unsubstituted or substituted C3-C 30 heteroaryl, or unsubstituted or substituted C6-C 30 arylamino, where R is an integer of 2 or greater when m is 2. 34 They are either the same or different from each other, and when n is an integer of 2 or greater, each R 35 They are the same or different from each other; and

[0033] m and n are each independent integers from 0 to 5.

[0034] As an example, the first luminescent material layer may be disposed between the first luminescent material layer and the second electrode.

[0035] The excited triplet energy level of the first compound may be higher than that of the second compound, and / or the excited triplet energy level of the fourth compound may be higher than that of the third compound.

[0036] Alternatively, the excited singlet energy level of the third compound may be higher than the excited singlet energy level of the fourth compound, and / or the excited singlet energy level of the fourth compound may be higher than the excited triplet energy level of the third compound.

[0037] The ratio of the intensity of the second emission peak to the intensity of the maximum emission peak of the second compound can be between about 0.20 and about 0.65.

[0038] The full width at one-quarter peak (FWQM) of the fourth compound is narrower than that of the second compound.

[0039] Alternatively, the light-emitting layer may include a first light-emitting part disposed between the first electrode and the second electrode, a second light-emitting part disposed between the first light-emitting part and the second electrode, and a first charge-generating layer disposed between the first light-emitting part and the second light-emitting part, wherein at least one of the first light-emitting part and the second light-emitting part includes the light-emitting material layer.

[0040] For example, the first light-emitting part may include the light-emitting material layer and / or the second light-emitting part may include a blue fluorescent light-emitting material layer, a blue phosphorescent light-emitting material layer, a blue delayed fluorescent light-emitting material layer, or the light-emitting material layer.

[0041] Alternatively, the light-emitting layer may further include a third light-emitting portion disposed between the second light-emitting portion and the second electrode, and a second charge-generating layer disposed between the second light-emitting portion and the third light-emitting portion.

[0042] In this case, at least one of the first light-emitting part and the third light-emitting part may include the light-emitting material layer.

[0043] On the other hand, as described above, an organic light-emitting device, such as an organic light-emitting display device or an organic light-emitting device, includes a substrate and an OLED disposed on the substrate.

[0044] A portion of the triplet exciton energy generated in a first luminescent material layer, which includes a phosphorescent material with excellent luminescence efficiency, induces phosphorescence emission. The remaining triplet excitons are transferred to an adjacent second luminescent material layer via triplet-triplet annihilation through the Dexter mechanism. The triplet exciton energy transferred to the second luminescent material layer is then transferred from a third compound to a singlet exciton in a fourth compound via triplet-triplet annihilation, ultimately resulting in fluorescence emission from the fourth compound.

[0045] Because the high-energy triplet excitons generated in the phosphorescent material are distributed into the fluorescent luminescent material layer, the concentration of triplet excitons in the phosphorescent luminescent material layer is reduced, thereby improving the driving stability of the OLED. The fluorescent material emits deep blue light and has excellent color purity and luminescence lifetime. Therefore, by including the luminescent material layer, it is possible to realize LEDs and organic light-emitting devices that can optimize color purity and luminescence lifetime and emit deep blue light.

[0046] It should be understood that the above general description and the following detailed description are exemplary and explanatory, intended to provide further explanation of the claimed inventive concept. Attached Figure Description

[0047] The accompanying drawings, which are included to provide a further understanding of this disclosure and are incorporated in and constitute a part of this application, illustrate embodiments of this disclosure and, together with the specification, serve to explain the principles of this disclosure.

[0048] Figure 1 This is a schematic circuit diagram of an organic light-emitting display device according to the present disclosure.

[0049] Figure 2 This is a schematic cross-sectional view illustrating an organic light-emitting display device according to an exemplary aspect of the present disclosure.

[0050] Figure 3 This is a schematic cross-sectional view illustrating an organic light-emitting diode (OLED) according to an exemplary aspect of the present disclosure.

[0051] Figure 4 This is a schematic diagram illustrating the luminescence mechanism of singlet and triplet energy levels in an luminescent material in an EML according to an exemplary aspect of this disclosure.

[0052] Figure 5 This is a schematic diagram showing the photoluminescence (PL) spectra of phosphorescent and fluorescent materials in an EML according to the present disclosure.

[0053] Figure 6 This is a schematic cross-sectional view of an OLED according to another exemplary aspect of this disclosure.

[0054] Figure 7 This is a schematic cross-sectional view illustrating an organic light-emitting display device according to another exemplary aspect of this disclosure.

[0055] Figure 8 This is a schematic cross-sectional view of an OLED according to another exemplary aspect of this disclosure.

[0056] Figure 9 This is a schematic cross-sectional view illustrating an organic light-emitting display device according to another exemplary aspect of this disclosure.

[0057] Figure 10 This is a schematic cross-sectional view of an OLED according to another exemplary aspect of this disclosure.

[0058] Figure 11 This is a schematic cross-sectional view of an OLED according to another exemplary aspect of this disclosure.

[0059] Figure 12 and 13 This is a graph showing the PL spectra of the phosphorescent and fluorescent materials in the embodiments of this disclosure.

[0060] Figure 14 and 15 This is a graph showing the PL spectrum of the luminescent material in the embodiments of this disclosure and the electroluminescence (EL) spectrum of the OLED.

[0061] Figures 16 to 19 This is a graph showing the PL spectrum of the luminescent material in the comparative example and the EL spectrum of the OLED. Detailed Implementation

[0062] The various aspects, embodiments, and examples of this disclosure will now be discussed in detail, some of which are illustrated in the accompanying drawings.

[0063] This disclosure relates to an organic light-emitting diode (OLED) in which a first compound and a second compound having tuned energy levels are applied in the same or adjacently arranged EML, and an organic light-emitting device having an OLED. OLEDs can be applied to organic light-emitting devices, such as organic light-emitting display devices and organic light-emitting emission devices. As an example, a display device using an OLED will be described.

[0064] Figure 1 This is a schematic circuit diagram of an organic light-emitting display device according to the present disclosure. Figure 1 As shown, in the organic light-emitting display device 100, gate line GL, data line DL, and power line PL intersect each other to define a pixel region P. Switching thin-film transistors Ts, driving thin-film transistors Td, storage capacitor Cst, and organic light-emitting diodes D are formed within the pixel region P. The pixel region P may include a first pixel region P1, a second pixel region P2, and a third pixel region P3. Figure 7 ).

[0065] A switching thin-film transistor (TFT) Ts is connected to the gate line GL and the data line DL. A driving thin-film transistor (TFT) Td and a storage capacitor Cst are connected between the switching TFT Ts and the power line PL. An organic light-emitting diode (OLED) D is connected to the driving TFT Td. When the switching TFT Ts is turned on by the gate signal applied to the gate line GL, the data signal applied to the data line DL is applied to the gate of the driving TFT Td and one electrode of the storage capacitor Cst through the switching TFT Ts.

[0066] The driving thin-film transistor Td is turned on by a data signal applied to its gate, causing a current proportional to the data signal to flow through the driving thin-film transistor Td from the power line PL to the organic light-emitting diode D. The organic light-emitting diode D then emits light with a brightness proportional to the current flowing through the driving thin-film transistor Td. In this case, the storage capacitor Cst is charged with a voltage proportional to the data signal, so that the voltage at the gate of the driving thin-film transistor Td remains constant during one frame. Therefore, the desired image can be displayed during the organic light-emitting display 100.

[0067] Figure 2 This is a schematic cross-sectional view illustrating an organic light-emitting display device 100 according to an exemplary aspect of this disclosure. All components of the organic light-emitting device according to all aspects of this disclosure are operatively coupled and configured. Figure 2 As shown, the organic light-emitting display device 100 includes a substrate 110, a thin-film transistor Tr on the substrate 110, and an organic light-emitting diode (OLED) D located above the substrate 110 and connected to the thin-film transistor Tr.

[0068] The substrate 110 may include, but is not limited to, glass, thin flexible materials, and / or polymeric plastics. For example, flexible materials may include, but are not limited to, polyimide (PI), polyethersulfone (PES), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polycarbonate (PC), and combinations thereof. The substrate 110 on which thin-film transistors (Tr) and OLEDDs are disposed forms an array substrate.

[0069] The buffer layer 122 can be disposed on the substrate 110, and the thin-film transistor Tr is disposed on the buffer layer 122. The buffer layer 122 can be omitted.

[0070] A semiconductor layer 120 is disposed above a buffer layer 122. In one exemplary aspect, the semiconductor layer 120 may include, but is not limited to, an oxide semiconductor material. In this case, a light-shielding pattern may be formed below the semiconductor layer 120, and the light-shielding pattern can prevent light from incident on the semiconductor layer 120, thereby preventing the semiconductor layer 120 from being photodegraded. Alternatively, the semiconductor layer 120 may include, but is not limited to, polysilicon. In this case, the opposite edges of the semiconductor layer 120 may be doped with impurities.

[0071] A gate insulating layer 124 made of an insulating material is disposed on the semiconductor layer 120. The gate insulating layer 124 may include, but is not limited to, inorganic insulating materials, such as silicon oxide (SiO2). x ) or silicon nitride (SiN) x ).

[0072] A gate 130, made of a conductive material such as metal, is disposed on the gate insulating layer 124 corresponding to the center of the semiconductor layer 120. While... Figure 2 The middle gate insulating layer 124 is disposed over the entire area of ​​the substrate 110, and the gate insulating layer 124 can be patterned in the same way as the gate 130.

[0073] An interlayer insulating layer 132 made of insulating material is disposed on the gate 130, covering the entire surface of the substrate 110. The interlayer insulating layer 132 may include, but is not limited to, silicon oxide (SiO2). x ) or silicon nitride (SiN) x Inorganic insulating materials, or organic insulating materials such as benzocyclobutene or propylene.

[0074] The interlayer insulating layer 132 has a first semiconductor layer contact hole 134 and a second semiconductor layer contact hole 136 exposing both sides of the semiconductor layer 120. The first semiconductor layer contact hole 134 and the second semiconductor layer contact hole 136 are disposed on opposite sides of the gate 130, and the first semiconductor layer contact hole and the second semiconductor layer contact hole 134 and 136 are formed on... Figure 2The gate insulating layer 124 is formed within the gate insulating layer 130. Alternatively, when the gate insulating layer 124 is patterned in the same way as the gate 130, the first semiconductor layer contact holes and the second semiconductor layer contact holes 134 and 136 are formed only within the interlayer insulating layer 132.

[0075] Source 144 and drain 146, made of a conductive material such as metal, are disposed on interlayer insulating layer 132. Source 144 and drain 146 are spaced apart from each other relative to gate 130 and contact both sides of semiconductor layer 120 through first semiconductor layer contact holes and second semiconductor layer contact holes 134 and 136, respectively.

[0076] Semiconductor layer 120, gate 130, source 144 and drain 146 constitute a thin-film transistor Tr used as a driving element. Figure 2 The thin-film transistor Tr has a coplanar structure in which the gate 130, source 144, and drain 146 are disposed above the semiconductor layer 120. Alternatively, the thin-film transistor Tr may have an inverted staggered structure in which the gate is disposed below the semiconductor layer and the source and drain are disposed above the semiconductor layer. In this case, the semiconductor layer may include amorphous silicon.

[0077] Gate lines GL and data lines DL that intersect to define pixel regions P, and switching elements Ts connected to gate lines GL and data lines DL can be further formed in... Figure 1 In the pixel region P, the switching element Ts is connected to the thin-film transistor Tr, which serves as the driving element. Furthermore, the power line PL is spaced parallel to the gate line GL or the data line DL, and the thin-film transistor Tr may also include a storage capacitor Cst, which is configured to maintain a constant voltage at the gate 130 during a frame.

[0078] A passivation layer 150 is disposed on the source 144 and drain 146 over the entire substrate 110. The passivation layer 150 has a flat top surface and a drain contact hole 152 that exposes the drain 146 of the thin-film transistor Tr. When the drain contact hole 152 is disposed on the second semiconductor layer contact hole 136, it can be spaced apart from the second semiconductor layer contact hole 136.

[0079] The OLED D includes a first electrode 210 disposed on a passivation layer 150 and connected to the drain 146 of a thin-film transistor Tr. The OLED D also includes a light-emitting layer 220 and a second electrode 230 disposed sequentially on the first electrode 210.

[0080] A first electrode 210 is disposed in each pixel region. The first electrode 210 may be an anode and comprises a conductive material having a relatively high work function value. For example, the first electrode 210 may include, but is not limited to, transparent conductive oxide (TCO).

[0081] In one exemplary aspect, when the organic light-emitting display device 100 is bottom-emitting, the first electrode 210 may have a single-layer structure of transparent conductive material. Alternatively, when the organic light-emitting display device 100 is top-emitting, a reflective electrode or reflective layer may be disposed below the first electrode 210.

[0082] For example, the reflective electrode or reflective layer may include, but is not limited to, a silver (Ag) or aluminum palladium copper (APC) alloy. In a top-emitting OLED D, the first electrode 210 may have a three-layer structure of ITO / Ag / ITO or ITO / APC / ITO. Furthermore, a bank layer is disposed on the passivation layer 150 to cover the edge of the first electrode 210. The bank layer 160 is exposed at the center of the first electrode 210 corresponding to the pixel region P.

[0083] A light-emitting layer 220 is disposed on the first electrode 210. In one exemplary aspect, the light-emitting layer 220 may have a single-layer structure of a light-emitting material layer (EML). Alternatively, the light-emitting layer 220 may have a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), an EML, a hole blocking layer (HBL), an electron transport layer (ETL), and / or an electron injection layer (EIL). Figure 3 and 6 On one hand, the light-emitting layer 220 may have one light-emitting part. Alternatively, the light-emitting layer 220 may have multiple light-emitting parts to form a series structure.

[0084] The second electrode 230 is disposed above the substrate 110, and the light-emitting layer 220 is disposed above the substrate 110. The second electrode 230 can be disposed over the entire display area and can include a conductive material with a relatively low work function value compared to the first electrode 210. The second electrode 230 can be a cathode. When the organic light-emitting display device 100 is a top-emitting type, the second electrode 230 is thinner to have light-transmitting (semi-transmitting) characteristics.

[0085] Furthermore, the encapsulation film 170 can be disposed above the second electrode 230 to prevent external moisture from penetrating into the OLED D. The encapsulation film 170 can have a laminated structure of, but is not limited to, an inorganic insulating film 172, an organic insulating film 174, and a second inorganic insulating film 176.

[0086] Furthermore, the organic light-emitting display device 100 may include a polarizer to reduce external light reflection. For example, the polarizer may be a circular polarizer. When the organic light-emitting display device 100 is a bottom-emitting type, the polarizer may be disposed below the substrate 110. Alternatively, when the organic light-emitting display device 100 is a top-emitting type, the polarizer may be disposed above the encapsulation film 170. Additionally, a cover window may be attached to the encapsulation film 170 or the polarizer. In this case, the substrate 110 and the cover window may be flexible, thus the organic light-emitting display device 100 may be a flexible display device.

[0087] Now, we will describe OLED in more detail. Figure 3 This is a schematic cross-sectional view of an OLED according to an exemplary aspect of this disclosure. Figure 3 As shown, OLED D1 includes a first electrode 210 and a second electrode 230 facing each other, and a light-emitting layer 220 having a single light-emitting portion disposed between the first electrode 210 and the second electrode 230. The organic light-emitting display device 100 includes a red pixel region, a green pixel region, and a blue pixel region, and OLED D1 can be disposed in the blue pixel region.

[0088] The light-emitting layer 220 includes an EML 240 disposed between the first electrode 210 and the second electrode 230. Furthermore, the light-emitting layer 220 may include at least one of an HTL 260 disposed between the first electrode 210 and the EML 240 and an ETL 270 disposed between the second electrode 230 and the EML 240. Additionally, the light-emitting layer 220 may also include at least one of a HIL 250 disposed between the first electrode 210 and the HTL 260 and an EIL 280 disposed between the second electrode 230 and the ETL 270. Alternatively, the light-emitting layer 220 may also include an EBL 265 disposed between the HTL 260 and the EML 240 and / or an HBL 275 disposed between the EML 240 and the ETL 270.

[0089] The first electrode 210 can be an anode that provides holes to the EML 240. The first electrode 210 can be, but is not limited to, a conductive material with a relatively high work function value, such as a transparent conductive oxide (TCO). More specifically, the first electrode 210 can be, but is not limited to, indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), tin oxide (SnO), zinc oxide (ZnO), cerium-doped indium oxide (ICO), aluminum-doped zinc oxide (Al:ZnO, AZO), etc.

[0090] The second electrode 230 can be a cathode that provides electrons to the EML 240. The second electrode 230 can be, but is not limited to, a conductive material with a relatively low work function value, i.e., a highly reflective material. For example, the second electrode 230 can be, but is not limited to, aluminum (Al), magnesium (Mg), calcium (Ca), silver (Ag), their alloys or combinations thereof, such as aluminum-magnesium alloys (Al-Mg), etc.

[0091] EML 240 includes a first EML (EML1) 242 disposed between EBL 265 and HBL 275 and a second EML (EML2) 244 disposed adjacent to EML1 242. EML1 242 performs phosphorescent emission and EML2 244 performs triplet-triplet annihilation (TTA).

[0092] When holes and electrons meet and form excitons in EML 240, singlet excitons with paired spin states and triplet excitons with unpaired spin states are generated in a 1:3 spin alignment ratio. Since conventional fluorescent materials can only utilize singlet excitons, their luminescence efficiency is very low. Phosphorescent materials can utilize both triplet and singlet excitons, but their luminescence lifetime is too short for commercial applications. According to this disclosure, by introducing EML 1 242 for phosphorescent emission and EML 2 244 for TTA (Telephoto Acrylamide), deep blue emission with improved color purity and luminescence lifetime can be achieved.

[0093] As an example, when the organic light-emitting display device 100 ( Figure 2 When the OLED is a top-emitting type, in EML1 242 and EML2 244, any EML containing a luminescent material having a maximum emission peak (PL peak) in a relatively short wavelength range can be disposed adjacent to the second electrode 230 used as a cathode. In this case, the cavity effect is maximized, and the luminous efficiency of the OLED D1 can be maximized. In one exemplary aspect, EML2 244 including a fluorescent material can be disposed between EML1 242 and HBL275, but is not limited thereto.

[0094] EML1 242 comprises a first compound (compound 1) as a first host and a second compound (compound 2) as a phosphorescent material. EML2 244 comprises a third compound (compound 3) as a second host and a fourth compound (compound 4) as a fluorescent material. The first compound may be a phosphorescent host and may have the structure of Formula 1:

[0095] [Formula 1]

[0096]

[0097] In Equation 1,

[0098] R 1 and R 2 Each is independently an unsubstituted or substituted carbazolyl group, or an unsubstituted or substituted carbazolyl group;

[0099] R 3 It is hydrogen, cyano, unsubstituted or substituted C1-C 20 Alkyl, unsubstituted or substituted C6-C 30 aryl, or unsubstituted or substituted C3-C 30 Mixed aromatics;

[0100] Z is N or CR 4 , where R 4 Hydrogen, unsubstituted or substituted C1-C 10 Alkyl, unsubstituted or substituted C6-C 30 aryl, or unsubstituted or substituted C3-C 30 heteroaryl; and

[0101] L 1 and L 2 Each is independently a single bond, unsubstituted or substituted C6-C 30 Aryl styrene, or unsubstituted or substituted C3-C 30 Mixed aromatics support the base.

[0102] As an example, R 1 and R 2 The carbazoyl and carbaolinyl groups, R 3 C6-C 30 Aryl and C3-C 30 heteroaryl, and L 1 and L 2 C6-C 30 Aryl and C3-C 30 Each of the heteroaryl groups can be independently unsubstituted or replaced by a cyano group, such as C6-C. 20 C6-C of aryl 30 Aryl and such C3-C 20 C3-C of heteroaryl 30 At least one of the heteroaryl groups is substituted.

[0103] As used herein, the term “unsubstituted” refers to hydrogen atom bonding, and in this case, hydrogen atoms include protium, deuterium, and tritium.

[0104] As used herein, the term "substitution" includes, but is not limited to, deuterium, tritium, unsubstituted or deuterium- or halogen-substituted C1-C groups. 20 Alkyl, unsubstituted or halogenated C1-C 20 Alkoxy, halogen, cyano, -CF3, hydroxy, carboxyl, carbonyl, amino, C1-C 10Alkylamino, C6-C 30 arylamino, C3-C 30 heteroarylamino, C6-C 30 Aryl, C3-C 30 heteroaryl, nitro, hydrazine, sulfonate, C1-C 20 Alkyl silyl, C6-C 30 Arylsilyl and C3-C 30 Heteroarylsilyl group.

[0105] As used herein, the term "hetero" in terms such as "heteroaromatic", "heteroaryl", "heteroarylalkyl", "heteroaryloxy", "heteroarylamino" and "heteroaryl styrene" refers to at least one carbon atom constituting an aromatic group or ring, for example, 1 to 5 carbon atoms being substituted by at least one heteroatom selected from N, O, S, P and combinations thereof.

[0106] As used in this article, C6-C 30 Aryl groups may include, but are not limited to, non-fused or fused aryl groups, such as phenyl, biphenyl, terphenyl, naphthyl, anthracene, pentalenyl, indenyl, indeno-indenyl, heptalenyl, biphenylenyl, indacenyl, phenalenyl, phenanthrenyl, benzo-phenanthrenyl, dibenzo-phenanthrenyl, azulenyl, pyrenyl, fluoranthenyl, and triphenylenyl. Chrysenyl, tetraphenylenyl, tetracenyl, pleiadenyl, picenyl, pentaphenylenyl, pentaphenylenyl, fluorenyl, indeno-fluorenyl, and spirofluorenyl.

[0107] As used in this article, C3-C 30Heteroaryl groups can be independent of, but are not limited to, unfused or fused heteroaryl groups, such as pyrroloyl, pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, tetraazinyl, imidazolyl, pyrazolyl, indoleyl, isoindoleyl, indolizinyl, pyrroloazinyl, carbazoleyl, benzo[a]carbazoleyl, dibenzo[a]carbazoleyl, indolecarbazoleyl, indo[a]carbazoleyl, benzofuran[a]carbazoleyl, benzo[a]thiophene[a]carbazoleyl, carbolinel, quinolinyl, isoquinolinyl, phthalazinyl, quinoxalinyl, cinnamyl, quinazolinyl, quinolinyl, purinyl, benzo[a]quinolinyl, benzo[a]isoquinolinyl, benzo[a]quinoxalinyl, benzo[a]quinoxalinyl, acridineyl, phenazinyl, phenoxalyl Azinyl, phenothiazinyl, phenanthrolinel, piperidinyl, phenanthidyl, pteridinyl, naphthidyl, furanyl, pyranyl, oxazinyl, oxazolyl, oxadiazolyl, triazolyl, dioxoalkyl, benzofuranyl, dibenzofuranyl, thiopyranyl, xanthaneyl, chromenyl, isochromenyl, thiazinyl, thiopheneyl, benzothiopheneyl, dibenzothiopheneyl, difuran-pyazinyl, benzofuran-dibenzofuranyl, benzothiopheneyl-benzothiopheneyl, benzothiopheneyl-dibenzothiopheneyl, benzothiopheneyl-benzofuranyl, benzothiopheneyl-dibenzofuranyl, N-substituted spirofluorenyl, spirofluorenyl-acridyl, and spirofluorenyl-xanthaneyl.

[0108] As an example, R in Equation 1 3 It can be, but is not limited to, hydrogen, cyano, C1-C5 alkyl, or unsubstituted or substituted with at least one of cyano, phenyl, and carbazole, and L 1 and L 2 Each of them may be, but is not limited to, an unsubstituted or substituted phenyl group, or a phenyl group substituted with at least one of C1-C5 alkyl, cyano, phenyl and carbazole groups.

[0109] For example, the first compound H1 included in EML1 242 can be selected from, but is not limited to, organic compounds having the structure of Formula 2:

[0110] [Equation 2]

[0111]

[0112] The second compound is a phosphorescent material that can emit triplet excitons via intersystem crossing (ISC). The second compound can be a platinum-based complex with tetradentate ligands and can have the structure of Formula 3:

[0113] [Formula 3]

[0114]

[0115] In Equation 3,

[0116] R 11 To R14 Each is independently hydrogen, halogen, cyano, unsubstituted or substituted C1-C 10 Alkyl, unsubstituted or substituted C1-C 10 Alkylamino, unsubstituted or substituted C6-C 30 Aryl, unsubstituted or substituted C3-C 30 Heteroaryl, or unsubstituted or substituted adamantyl.

[0117] As an example, R 11 To R 14 C6-C 30 Aryl, C3-C 30 The heteroaryl and adamantyl groups are each independently unsubstituted or C1-C. 10 Alkyl, C6-C 30 Aryl (e.g., C6-C) 20 aryl) and C3-C 30 heteroaryl (e.g., C3-C) 20 At least one of the aryl groups is substituted.

[0118] For example, R in Equation 3 11 It can be hydrogen, unsubstituted or substituted C1-C5 alkyl, unsubstituted or substituted phenyl, or unsubstituted or substituted adamantyl, R in Formula 3 12 It can be hydrogen, unsubstituted or substituted C1-C5 alkyl, unsubstituted or substituted (e.g., phenyl-substituted) adamantyl, and R in Formula 3 13 It can be hydrogen, unsubstituted or substituted C1-C5 alkyl, unsubstituted or substituted (e.g., at least one phenyl-substituted) carbazole, or unsubstituted or substituted (e.g., at least one phenyl-substituted) phenyl, and R in Formula 3 14 It can be hydrogen, or unsubstituted or substituted C1-C5 alkyl, but is not limited thereto.

[0119] As an example, the second compound included in EML1 242 may be selected from, but is not limited to, organic compounds having the structure of Formula 4:

[0120] [Formula 4]

[0121]

[0122]

[0123] While the second compound with the structure of Formula 3 exhibits excellent luminescence efficiency, it is difficult to achieve a deep blue color and has a short luminescence lifetime. However, in this exemplary aspect, the excitons generated in the second compound are distributed in EML1 242, which includes a second compound containing phosphorescent material and emits phosphorescence via ISC, and in EML2 244, which includes a fourth compound emitting fluorescence. The mixing of phosphorescent and fluorescent emission, by reducing the concentration of triplet excitons in EML1 242, can improve the color purity of EML 240 and extend its luminescence lifetime.

[0124] More specifically, EML 240 includes EML 244, which is adjacent to EML1 242 and implements TTA. TTA is the phenomenon of forming a singlet state through the interaction or collision of molecules excited into a triplet state, and occurs when the density of triplet excitons is high.

[0125] In OLEDs using fluorescent materials, if triplet excitons are additionally used, 15% of the 75% of triplet excitons are regenerated into singlet intermediates. In this case, if the initially generated 25% of singlet excitons are included, a total of 40% of singlet excitons can be formed. Therefore, the external quantum efficiency is 8-12% by using the TTA mechanism for optical coupling efficiency. Specifically, under the relationship that the sum of the energies of the two triplet excitons is greater than the energy of the singlet exciton (2T1>S1), the collision of two triplet excitons can probabilistically produce a singlet exciton. In this case, 37.5%, i.e., half of the initially generated triplet excitons, can be regenerated into singlet excitons for upward transfer, up to a maximum of 62.5% of singlet excitons can be generated, and an external quantum efficiency of up to 12.5%-18.8% can be achieved.

[0126] In the TTA process, since the collision of two triplet excitons produces at most one singlet exciton, the luminous efficiency using the TTA process can be improved compared to simply utilizing fluorescence. Furthermore, when the TTA process is applied to OLEDs, a constant luminous efficiency can be achieved regardless of the current density.

[0127] EML2 244 comprises a third compound as the second host and a fourth compound as the fluorescent material. The third compound can act as an electron acceptor with a molecular structure that realizes the TTA mechanism, and the fourth compound as the fluorescent material can act as a photosensitizer. The third compound may include anthracene organic compounds having the structure of Formula 5:

[0128] [Formula 5]

[0129]

[0130] In Equation 5,

[0131] R 21 and R 22 Each is independently hydrogen, unsubstituted or substituted C1-C 20 Alkyl, unsubstituted or substituted C6-C 30 aryl, or unsubstituted or substituted C3-C 30 heteroaryl; and

[0132] R 23 and R 24 Each is independently unsubstituted or substituted C6-C 30 aryl, or unsubstituted or substituted C3-C 30 Mixed aromatic compounds.

[0133] As an example, R 21 To R 24 C6-C 30 Aryl and C3-C 30 Various heteroaryl groups are independently unsubstituted or C6-C substituted. 30 Aryl and C3-C 30 At least one of the heteroaryl groups is substituted. For example, R 21 and R 22 Each is independently hydrogen, unsubstituted or substituted C1-C5 alkyl, or unsubstituted or substituted phenyl, and R 23 and R 24 Each is independently an unsubstituted or naphthyl-substituted phenyl group, or an unsubstituted or substituted naphthyl group (e.g., 1-naphthyl or 2-naphthyl), but is not limited thereto.

[0134] Anthracite-based organic compounds with the structure of Formula 5 possess excellent quantum efficiency, stable electrochemical performance, and suitable excited triplet energy levels, making them suitable for blue luminescence. For example, the third compound that can realize the TTA properties as the second host can be selected from, but is not limited to, anthracene organic compounds having the following structure of Formula 6:

[0135] [Formula 6]

[0136]

[0137] The fourth compound included in EML2 244 can be a fluorescent material with a maximum emission peak similar to that of the second compound. For example, the fourth compound can be a fluorescent material in which excitons transition from the excited state to the ground state, and it has a narrower FWQM (full width at one-quarter of the peak) than the second compound, thus exhibiting excellent color purity. For example, the fourth compound can be a boron-based organic compound having the structure of Formula 7:

[0138] [Formula 7]

[0139]

[0140] In Equation 7,

[0141] R 31 To R 33 Each is independently hydrogen, halogen, cyano, unsubstituted or substituted C1-C 20 Alkyl, unsubstituted or substituted C6-C 30 Aryl, unsubstituted or substituted C3-C 30 heteroaryl, or unsubstituted or substituted C6-C 30 arylamino;

[0142] R 34 and R 35 Each is independently halogenated, cyano, unsubstituted or substituted C1-C. 20 Alkyl, unsubstituted or substituted C6-C 30 Aryl, unsubstituted or substituted C3-C 30 heteroaryl, or unsubstituted or substituted C6-C 30 arylamino, where R is an integer of 2 or greater. 34 They are either the same or different from each other, and when n is an integer of 2 or greater, each R 35 They are the same or different from each other; and

[0143] m and n are each an independent integer from 0 to 5.

[0144] As an example, R 31 To R 35 C6-C 30 Aryl, C3-C 30 heteroaryl, C6-C 30 The aryl amino groups are each independently unsubstituted or C1-C. 20 Alkyl, C6-C 30 Aryl and C3-C 30 At least one of the heteroaryl groups is substituted. For example, R 31 and R 32 Each is independently hydrogen, or unsubstituted or substituted C1-C 10 Alkyl (e.g., C1-C5 alkyl), R 33 It can be hydrogen, or unsubstituted or C1-C 10 Alkyl (e.g., C1-C5 alkyl) substituted biphenylamino, and R 34 and R 35 Each is independently hydrogen, unsubstituted or substituted C1-C 10Alkyl groups (e.g., C1-C5 alkyl groups), or unsubstituted or phenyl groups substituted with at least one phenyl group, but not limited thereto. As an example, the fourth compound may be selected from, but is not limited to, boron-based organic compounds having the structure of Formula 8:

[0145] [Formula 8]

[0146]

[0147]

[0148] In one exemplary aspect, the content of the second compound in EML1 242 can be greater than the content of the fourth compound in EML2 244. In this case, the triplet exciton energy generated in the second compound can ultimately be transferred to the fourth compound via the third compound. As an example, the content of the second compound in EML1 242 can be between about 5 and about 20 wt%, for example, about 5 to about 15 wt%, and the content of the fourth compound in EML2 244 can be between about 0.1 and about 5 wt%, for example, about 0.5 to about 3 wt%, but is not limited thereto.

[0149] Now, we will describe the light emission mechanism in EML 240. Figure 4 This is a schematic diagram illustrating the light emission mechanism of singlet and triplet energy levels in a luminescent material in an EML according to an exemplary aspect of this disclosure. In EML1 242, a first compound that achieves phosphorescence emission induces triplet excitons in a second compound of the phosphorescent material to participate in light emission without being quenched as non-emission extinction.

[0150] like Figure 4 Schematic illustration shows the excited triplet level T1 of the first compound contained in EML1 242. H1 and the excited singlet level S1 H1 The energy levels are respectively higher than the excited triplet energy level T1 of the second compound. PD and the excited singlet level S1 PD As an example, the triplet energy level T1 of the third compound. H1 and the excited singlet level S1 H1 It can be compared to the triplet energy level T1 of the second compound. PD and singlet level S1 PD The voltage is at least about 0.2 eV, for example, at least about 0.3 eV, for example, at least about 0.5 eV.

[0151] For example, when the triplet energy level T1 of the first compound H1 There is no triplet energy level T1 higher than that of the second compound. PD At that time, the triplet energy level T1 of the second compound PDThe exciton can be reverse-transferred to the triplet level T1 of the first compound. H1 In this case, when the triplet exciton cannot be emitted, the triplet exciton of the first compound, which is reverse-transferred to the first compound and cannot emit triplet excitons, is quenched as a non-emission extinction, so that the triplet exciton energy of the second compound cannot contribute to luminescence.

[0152] Furthermore, the excited singlet exciton level S1 of the third compound that acts as an electron acceptor in EML2 244 H2 Designed to achieve TTA, it can exceed the excited singlet state energy level S1 of the fourth compound, which acts as an α-photon acceptor. FD To achieve TTA, the excited triplet energy level T1 of the third compound... H2 It can be lower than the excited singlet state energy level S1 of the fourth compound. FD and / or excited triplet level T1 FD .

[0153] The singlet exciton energy generated in the fourth compound induces fluorescence emission via exciton recombination. The triplet exciton energy of the fourth compound is transferred to the third compound, which excites a triplet level T1. H2 Below the triplet energy level T1 of the fourth compound FD The third compound can be excited to the excited triplet level T1 by means of triplet-triplet energy transfer (TTEF) and / or by receiving exciton energy from the excited triplet energy of the second compound. H2 The third compound achieves its effect through the TTA mechanism at the excited singlet state S1. H2 Excitons are generated in the state and in the triplet energy level T1 H2 Excitons bind at other exciton sites in the state. The excited singlet state energy level S1 of the third compound. H2 The exciton energy at point S1 is transferred to the excited singlet level S1 of the fourth compound via the Foster resonance energy transfer (FRET) mechanism. FD The fourth compound emits light using the initial singlet exciton energy and a portion of the triplet singlet energy converted in the third compound.

[0154] To achieve excellent luminescence properties, it is necessary to adjust the photoluminescence (PL) characteristics between the second compound of the phosphorescent material and the fourth compound of the fluorescent material. Figure 5 This is a schematic diagram showing the photoluminescence (PL) spectra of phosphorescent and fluorescent materials in an EML according to the present disclosure.

[0155] The maximum PL peak λmax (PD) of the second compound can be equal to or less than about 470 nm, for example, between about 455 nm and about 465 nm, but is not limited thereto. Compared to the maximum PL peak λmax (PD) of the second compound, the maximum PL peak λmax (FD) of the fourth compound can be within about 15 nm. In one exemplary aspect, the maximum PL peak λmax (FD) of the fourth compound can be, but is not limited to, between about 440 nm and about 470 nm. Furthermore, the fourth compound has a quarter-peak full width at half maximum (FWQM). FD It can have a quarter-peak full width (FWQM) than the second compound. PD Narrow. As an example, the FWQM of the second compound. FD The fourth compound may have an FWQMFD between approximately 60 nm and approximately 80 nm, but is not limited to this.

[0156] Furthermore, the ratio of the intensity of the second emission peak (e.g., an emission peak formed in a relatively long wavelength range among multiple emission peaks) to the intensity of the first emission peak (e.g., an emission peak formed in a relatively short wavelength range among multiple emission peaks) can be equal to or less than about 0.65, for example, between about 0.20 and about 0.65. In this case, the excited triplet energy level of the second compound can be minimized to achieve luminescence stability, and the fourth compound can emit deep blue light with improved color purity and minimized reduction in optical coupling efficiency.

[0157] On the other hand, when the intensity of the second emission peak in the second compound is greater than that of the first emission peak—in other words, the second emission peak is the maximum emission peak λmax(PD)—the wavelength range shifted by the first emission peak, which is related to the triplet exciton energy, is too short. Because the excited triplet energy level of the second compound is too high, the triplet exciton quenches in the first compound of the first host, potentially reducing the luminous lifetime and luminous efficiency of OLED D1. Furthermore, as the FWQMPD of the emitted light increases, the optical coupling efficiency in EML 240 will be significantly reduced.

[0158] Back Figure 3HIL 250 is disposed between the first electrode 210 and the HTL 260, and improves the interfacial properties between the inorganic first electrode 210 and the organic HTL 260. In one exemplary aspect, HIL 250 may include, but is not limited to, 4,4',4”-tris(3-methylphenylamino)triphenylamine (MTDATA), 4,4',4”-tris(N,N-diphenyl-amino)triphenylamine (NATA), 4,4',4”-tris(N-(naphthyl-1-yl)-N-phenyl-amino)triphenylamine (1T-NATA), 4,4',4”-tris(N-(naphthyl-2-yl)-N-phenyl-amino)triphenylamine (2T-NATA), copper phthalocyanine (CuPc), tris(4-carbazole-9-yl-phenyl)amine (TCTA), N,N'-diphenyl-N,N'-bis(1-naphthyl)-1, 1'-Biphenyl-4,4”-diamine (NPB; NPD), 1,4,5,8,9,11-hexaazatriphenylhexacarbonitrile (dipyrazine[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)polystyrene sulfonate (PEDOT / PSS), N-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluorene-2-amine and combinations thereof.

[0159] In another exemplary aspect, HIL 260 may include hole transport materials doped with hole injection dopants (p-dopers). Hole injection dopants may include, but are not limited to, HAT-CN, CuPc, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinone dimethyl ether (F4-TCNQ), 7,7,8,8-tetracyanoquinone dimethyl ether (F6-TCNQ), 2,2-(perfluoronaphthalene-2,6-dimethylene)-diammonium nitrile (F6-TCNNQ), FeCl3, V2O5, WO3, MoO3, ReO3, Fe3O4, MnO2, SnO2, CoO2, TiO2, and combinations thereof. In this case, the content of the hole injection dopant in HIL 250 may be, but is not limited to, from about 1 to about 10 wt%. Depending on the structure of OLED D1, HIL 250 may be omitted.

[0160] HTL 260 is positioned between HIL 250 and EML 240. In one exemplary aspect, HTL 260 may include, but is not limited to, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD), NPB, 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (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-tolyl-amino)-phenyl]cyclohexane (TAPC), 5-di(9H-carbazole-9-yl)-N,N-diphenylaniline (DCDPA), N-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazole-3-yl)phenyl)-9H-fluorene-2-amine, N-(biphenyl-4-yl)-N-(4-(9-phenyl-9H-carbazole-3-yl)phenyl)biphenyl-4-amine and combinations thereof.

[0161] ETL 270 and EIL 280 may be sequentially laminated between EML 240 and the second electrode 230. ETL 270 comprises a material with high electron mobility to stably provide electrons to EML 240 via rapid electron transfer. In one exemplary aspect, ETL 270 may include, but is not limited to, compounds based on oxadiazole, compounds based on triazole, compounds based on phenanthroline, compounds based on benzoxazole, compounds based on benzothiazole, compounds based on benzimidazole, triazine compounds, etc.

[0162] As an example, ETL 270 may include, but is not limited to, tris-(8-hydroxyquinoline aluminum (Alq3), 2-biphenyl-4-yl-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD), spiro-PBD, lithium quinoline (Liq), 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBi), bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum (BAlq), 4,7-diphenyl-1,10-phenanthroline (Bphen), 2,9-bis(naphthyl-2-yl)4,7-diphenyl-1,10-phenanthroline (NBphen), 2-phenyl-9-(3-(2-phenyl-1,10-phenanthroline-9-yl)phenyl)-1,10-phenanthroline (PBPPhen), and 2,9-dimethyl-4,7-diphenyl 3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4-(naphthyl-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), 1,3,5-tris(p-pyridin-3-yl-phenyl)benzene (TpPyPB), 2,4,6-tris(3'-(pyridin-3-yl)biphenyl) Benzene-3-yl)1,3,5-triazine (TmPPPyTz), poly[9,9-bis(3'-(N,N-dimethyl)-N-ethylammonium)-propyl)-2,7-fluorene]-alt-2,7-(9,9-dioctylfluorene)](PFNBr), tris(phenylquinoxaline) (TPQ), diphenyl[4-(triphenylsilyl)phenyl]phosphine oxide (TSPO1) and combinations thereof.

[0163] The EIL 280, disposed between the second electrode 230 and the ETL 270, can improve the physical properties of the second electrode 230, thereby increasing the luminous lifetime of the OLED D1. In one exemplary aspect, the EIL 280 may include, but is not limited to, alkali metal halides or alkaline earth metal halides, such as LiF, CsF, NaF, BaF2, etc., and / or organometallic compounds, such as lithium quinoline, lithium benzoate, sodium stearate, etc.

[0164] When holes are transferred to the second electrode 230 via EML 240 and / or electrons are transferred to the first electrode 210 via EML 240, the OLED D1 may have a shorter lifetime and reduced luminous efficiency. To prevent these phenomena, the OLED D1 according to this disclosure may have at least one exciton blocking layer adjacent to EML 240.

[0165] For example, an exemplary aspect of the OLED D1 includes an EBL265 between the HTL 260 and EML 240 to control and prevent electron transfer. In one exemplary aspect, the EBL 265 may include, but is not limited to, TCTA, tris[4-(diethylamino)phenyl]amine, N-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluorene-2-amine, TAPC, MTDATA, mCP, mCBP, CuPc, N,N'-di[4-(di(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.

[0166] Furthermore, the OLED D1 may also include an HBL 275 as a second exciton blocking layer between the EML 240 and the ETL 270, preventing holes from transferring from the EML 240 to the ETL 270. In one exemplary aspect, the HBL 275 may include, but is not limited to, any of the following compounds that can be used in the ETL 270: oxadiazole-based compounds, triazole-based compounds, phenanthroline-based compounds, benzoxazole-based compounds, benzothiazole-based compounds, benzimidazole-based compounds, and triazine-based compounds.

[0167] For example, HBL 275 may include compounds having a relatively low HOMO energy level compared to the HOMO energy level of the luminescent material in EML 240. HBL 275 may include, but is not limited to, BCP, BAlq, Alq3, PBD, spiro-PBD, Liq, di-4,5-(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.

[0168] According to an exemplary aspect, OLED D1 includes EML1 242 and EML2 244, EML1 242 comprising a phosphorescent material, and EML2 244 implementing TTA and disposed adjacent to EML1 242. OLED D1 can achieve deep blue light with excellent color purity and maximize luminous lifetime.

[0169] In an alternative, OLEDs can include multiple light-emitting components. Figure 6 This is a schematic cross-sectional view of an OLED according to another exemplary aspect of this disclosure. Figure 6As shown, OLED D2 includes a first electrode 210 and a second electrode 230 facing each other, and a light-emitting layer 220A having two light-emitting portions disposed between the first electrode 210 and the second electrode 230. Organic light-emitting display device 100 ( Figure 2 The OLED D2 includes a red pixel area, a green pixel area, and a blue pixel area, and the OLED D2 can be located in the blue pixel area. The first electrode 210 can be the anode, and the second electrode 230 can be the cathode.

[0170] The light-emitting layer 220A includes a first light-emitting portion 320 and a second light-emitting portion 420. The first light-emitting portion 320 includes a first EML (lower EML) 340 and a second light-emitting portion 420 including a second EML (upper EML) 440. In addition, the light-emitting layer 220A may also include a charge generation layer (CGL) 380 disposed between the first light-emitting portion 320 and the second light-emitting portion 420.

[0171] CGL 380 is disposed between the first light-emitting part and the second light-emitting parts 320 and 420, such that the first light-emitting part 320, CGL 380 and the second light-emitting part 420 are sequentially disposed on the first electrode 210. In other words, the first light-emitting part 320 is disposed between the first electrode 210 and CGL 380, and the second light-emitting part 420 is disposed between the second electrode 230 and CGL 380.

[0172] The first light-emitting portion 320 includes a lower EML 340. The first light-emitting portion 320 may further include at least one of the following: a HIL 350 disposed between the first electrode 210 and the lower EML 340; a first HTL (HTL1) 360 disposed between the HIL 350 and the lower EML 340; and a first ETL (ETL1) 370 disposed between the lower EML 340 and the CGL 380. Alternatively, the first light-emitting portion 320 may further include a first EBL (EBL1) 365 disposed between the HTL1 360 and the lower EML 340 and / or a first HBL (HBL1) 375 disposed between the lower EML 340 and the ETL1 370.

[0173] The second light-emitting part 420 includes an upper EML 440. The second light-emitting part 420 may further include at least one of a second HTL (HTL2) 460 disposed between CGL380 and the upper EML 440, a second ETL (ETL2) disposed between the upper EML 440 and the second electrode 230, and an EIL 480 disposed between ETL2 470 and the second electrode 230. Alternatively, the second light-emitting part 420 may further include a second EBL (EBL2) 465 disposed between HTL2 460 and the upper EML 440 and / or a second HBL (HBL2) 475 disposed between the upper EML 440 and ETL2 470.

[0174] CGL 380 is disposed between the first light-emitting part 320 and the second light-emitting part 420. The first light-emitting part 320 and the second light-emitting part 420 are connected by CGL 380. CGL 380 may be a PN-connected CGL, which connects an N-type CGL (N-CGL) 382 to a P-type CGL (P-CGL) 384.

[0175] N-CGL 382 is disposed between ETL1 370 and HTL2 460, and P-CGL 384 is disposed between N-CGL 382 and HTL2 460. N-CGL 382 transfers electrons to EML1 340 of the first light-emitting part 320, and P-CGL 384 transfers holes to EML2 440 of the second light-emitting part 420.

[0176] As an example, N-CGL 382 may comprise an electron transport material doped with an electron-injected dopant (n-dopant). The electron-injected dopant may include, but is not limited to, alkali metals such as Li, Na, K, and Cs and / or alkaline earth metals such as Mg, Sr, Ba, and Ra. The content of the electron-injected dopant in N-CGL 382 may be, but is not limited to, between about 0.05 and about 5 wt%. When the electron-injected dopant content in N-CGL 382 exceeds 5 wt%, excessive electron injection may lead to electron leakage or an increase in the driving voltage.

[0177] P-CGL 384 may include hole-implanting material doped with a hole-implanting dopant. As an example, the amount of hole-implanting dopant in the P-CGL may be between about 10 and about 20 wt%.

[0178] In this respect, each of the lower EML 340 and the upper EML 440 may be a blue luminescent material layer. For example, the lower EML 340 may include a first EML 342 containing a first compound and a second compound, and a second EML 344 containing a third compound and a fourth compound. The upper EML 440 may include a first EML 442 containing a first compound and a second compound, and a second EML 444 containing a third compound and a fourth compound. Alternatively, each of the first EMLs 342 and 442 may include a third compound and a fourth compound, and each of the second EMLs 344 and 444 may respectively include the first compound and the second compound.

[0179] Each of the first and second compounds contained in the first EML 342 of the lower EML 340 may be independently identical or different from each of the first and second compounds contained in the first EML 442 of the upper EML 440. Each of the third and fourth compounds contained in the second EML 344 of the lower EML 340 may be independently identical or different from each of the third and fourth compounds contained in the second EML 444 of the upper EML 440.

[0180] Alternatively, at least one of the lower EML 340 and the upper EML 440, for example, the upper EML 440 may have a monolayer structure. In this case, the upper EML 440 may include a blue host and a blue dopant. The blue dopant may include a first compound. The blue dopant may include at least one of a blue phosphorescent material, a blue delayed fluorescence material, and a blue fluorescent material. Therefore, the upper EML 440 can realize a blue phosphorescent EML, a blue delayed fluorescence EML, and / or a blue fluorescent EML.

[0181] In the OLED D2 of this aspect, each of the lower EML 340 and the upper EML 440 may respectively include a first EML 342 and 442 containing phosphorescent material, and a second EML 344 and 444 disposed adjacent to the first EML 342 and 442 respectively to realize TTA. Furthermore, since the OLED D2 has a double-layer structure with a blue luminescent material layer, the color sensitivity of the OLED D2 can be further improved, and the luminous efficiency of the OLED D2 can be further optimized.

[0182] Figure 7 This is a schematic cross-sectional view illustrating an organic light-emitting display device according to another exemplary aspect of this disclosure. Figure 7As shown, the organic light-emitting display device 500 includes a substrate 510 defining first to third pixel regions P1, P2, and P3, a thin-film transistor Tr disposed above the substrate 510, and an OLED D disposed above and connected to the thin-film transistor Tr. As an 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.

[0183] The substrate 510 can be a glass substrate or a flexible substrate. For example, the flexible substrate can 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 disposed above the substrate 510, and the thin-film transistor Tr is disposed above the buffer layer 512. The buffer layer 512 can be omitted. Figure 2 As shown, the thin-film transistor Tr includes a semiconductor layer, a gate, a source, and a drain, and is used as a driving element.

[0184] A passivation layer 550 is disposed above the thin-film transistor Tr. The passivation layer 550 has a flat top surface and includes a drain contact hole 552 that exposes the drain of the thin-film transistor Tr.

[0185] OLED D is disposed above passivation layer 550 and includes a first electrode 610 connected to the drain of thin-film transistor Tr, and a light-emitting layer 620 and a second electrode 630 sequentially disposed on the first electrode 610. OLED D is disposed in each of the first to third pixel regions P1, P2, and P3, and emits different light in each pixel region. For example, OLED D in the first pixel region P1 can emit blue light, OLED D in the second pixel region P2 can emit green light, and OLED D in the third pixel region P3 can emit red light.

[0186] The first electrode 610 is formed independently for each of the first to third pixel regions P1, P2 and P3, and the second electrode 630 is formed integrally with respect to the first to third pixel regions P1, P2 and P3.

[0187] The first electrode 610 can be one of the anode and the cathode, and the second electrode 630 can be the other of the anode and the cathode. In addition, one of the first electrode 610 and the second electrode 630 can be a transmission (or semi-transmission) electrode, while the other of the first electrode 610 and the second electrode 630 can be a reflection electrode.

[0188] For example, the first electrode 610 can be an anode and may include a transparent conductive oxide layer of a conductive material with a relatively high work function value, namely a transparent conductive oxide (TCO). The second electrode 630 can be a cathode and may include a metallic material layer of a conductive material with a relatively low work function value, namely 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 include Al, Mg, Ca, Ag, alloys thereof (e.g., Mg-Ag), or combinations thereof.

[0189] When the organic light-emitting display device 500 is bottom-emitting, the first electrode 610 can have a single-layer structure with a transparent conductive oxide layer. Alternatively, when the organic light-emitting display device 500 is top-emitting, a reflective electrode or reflective layer can be disposed below the first electrode 610. For example, the reflective electrode or reflective layer may include, but is not limited to, Ag or APC alloys. In a top-emitting OLED D, the first electrode 610 can have a three-layer structure of ITO / Ag / ITO or ITO / APC / ITO. Furthermore, the second electrode 630 is thinner to have light-transmitting (or semi-transmitting) properties.

[0190] A dam layer 560 is disposed above the passivation layer 550 to cover the edge of the first electrode 610. The dam layer 560 corresponds to each of the first to third pixel regions P1, P2, and P3 and exposes the center of the first electrode 610. (First electrode 610)

[0191] A light-emitting layer 620 is disposed on the first electrode 610. In one exemplary aspect, the light-emitting layer 620 may have a single-layer structure of EML. Alternatively, the light-emitting layer 620 may include at least one of HIL, HTL, and EBL disposed sequentially between the first electrode 610 and the EML, and / or HBL, ETL, EIL, and / or CGL disposed sequentially between the EML and the second electrode 630.

[0192] In one exemplary aspect, the EML of the emissive layer 630 in the first pixel region P1 of the blue pixel region may include an EML1 642 containing a first compound and a second compound. Figure 8 ) and EML2644, which contains the third and fourth compounds. Figure 8 ).

[0193] An encapsulation film 570 is disposed above the second electrode 630 to prevent external moisture from penetrating into the OLED D. The encapsulation film 570 may have, but is not limited to, a three-layer structure film with a first inorganic insulating layer, an organic insulating layer, and a second inorganic insulating layer.

[0194] The organic light-emitting display device 500 may have a polarizer to reduce external light reflection. For example, the polarizer may be a circular polarizer. When the organic light-emitting display device 500 is a bottom-emitting type, the polarizer may be disposed below the substrate 510. Alternatively, when the organic light-emitting display device 500 is a top-emitting type, the polarizer may be disposed above the encapsulation film 570.

[0195] Figure 8 This is a schematic cross-sectional view of an OLED illustrating yet another exemplary aspect of this disclosure. (See diagram below.) Figure 8 As shown, the OLED D3 includes a first electrode 610, a second electrode 630 facing the first electrode 610, and a light-emitting layer 620 disposed between the first electrode 610 and the second electrode 630.

[0196] The first electrode 610 can be an anode and the second electrode 630 can be a cathode. As an example, the first electrode 610 can be a reflective electrode and the second electrode 630 can be a transmissive (or semi-transmissive) electrode.

[0197] The light-emitting layer 620 includes an EML 640. The light-emitting layer 620 may include at least one of an HTL 660 disposed between the first electrode 610 and the EML 640 and an ETL 670 disposed between the EML 640 and the second electrode 630. Furthermore, the light-emitting layer 620 may also include at least one of a HIL 650 disposed between the first electrode 610 and the HTL 660 and an EIL 680 disposed between the ETL 670 and the second electrode 630. Additionally, the light-emitting layer 620 may also include at least one of an EBL 665 disposed between the HTL 660 and the EML 640 and an HBL 675 disposed between the EML 640 and the ETL 670.

[0198] Furthermore, the light-emitting layer 620 may also include an auxiliary hole transport layer (auxiliary HTL) 662 disposed between the HTL 660 and the EBL 665. The auxiliary HTL 662 may include a first auxiliary HTL 662a located in the first pixel region P1, a second auxiliary HTL 662b located in the second pixel region P2, and a third auxiliary HTL 662c located in the third pixel region P3.

[0199] The first auxiliary HTL 662a has a first thickness, the second auxiliary HTL 662b has a second thickness, and the third auxiliary HTL 662c has a third thickness. The first thickness is less than the second thickness, and the second thickness is less than the third thickness. Therefore, OLEDD3 has a micro-cavity structure.

[0200] Because the first to third auxiliary HTLs 662a, 662b, and 662c have different thicknesses, the distance between the first electrode 610 and the second electrode 630 in the first pixel region P1, which emits light in the first wavelength range (blue light), is smaller than the distance between the first electrode 610 and the second electrode 630 in the second pixel region P2, which emits light in the second wavelength range (green light), and is longer than the first wavelength range. Furthermore, 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, which emits light in the third wavelength range (red light), and is longer than the second wavelength range. Therefore, the luminous efficiency of the OLED D5 is improved.

[0201] exist Figure 8 In the first pixel region P1, the first auxiliary HTL 662a is located. Alternatively, the OLED D5 can achieve a microcavity structure without the first auxiliary HTL 662a. Furthermore, a capping layer can be disposed above the second electrode 630 to improve the external coupling of light emitted from the OLED D3.

[0202] EML 640 includes EML1 642 and EML2 644 located in the first pixel region P1, a third EML (EML3) 646 located in the second pixel region P2, and a fourth EML (EML4) 648 located in the third pixel region P3. Each of EML1 and EML2 642 and 644, EML3 646 and EML4 648 can be a blue EML, a green EML, and a red EML, respectively.

[0203] In one exemplary aspect, EML1 642 located in the first pixel region P1 may include a first compound and a second compound, and EML2 644 may include a third compound and a fourth compound. Alternatively, EML1 642 may include a third compound and a fourth compound, and EML2 644 may include a first compound and a second compound.

[0204] EML3 646, located in the second pixel region P2, may include a host and a green dopant, and EML4 648, located in the third pixel region P3, may include a host and a red dopant. For example, the host in EML3 646 and EML4 648 may include a first compound, and each of the green and red dopant may include at least one of a green or red phosphorescent material, a green or red delayed fluorescence material, and a green or red fluorescent material.

[0205] OLED D3 emits blue, green, and red light from its first to third pixel regions P1, P2, and P3, respectively, enabling the organic light-emitting display device 500 (… Figure 7 It can produce full-color images.

[0206] 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 improving the color purity of the light emitted from the OLED D. As an 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.

[0207] When the organic light-emitting display device 500 is a bottom-emitting type, the color filter layer can be disposed between the OLED D and the substrate 510. Alternatively, when the organic light-emitting display device 500 is a top-emitting type, the color filter layer can be disposed above the OLED D.

[0208] Figure 9 This is a schematic cross-sectional view illustrating an organic light-emitting display device according to yet another exemplary aspect of this disclosure. Figure 9 As shown, the organic light-emitting display device 1000 includes a substrate 1010 defining a first pixel region P1, a second pixel region P2, and a third pixel region P3; a thin-film transistor Tr disposed above the substrate 1010; an OLED D disposed above 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. As an 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.

[0209] Substrate 1010 can be a glass substrate or a flexible substrate. For example, the flexible substrate can be any of a PI substrate, a PES substrate, a PEN substrate, a PET substrate, and a PC substrate. The thin-film transistor Tr is located above substrate 1010. Alternatively, a buffer layer can be disposed above substrate 1010 and the thin-film transistor Tr can be disposed above the buffer layer. Figure 2 As shown, the thin-film transistor Tr includes a semiconductor layer, a gate, a source, and a drain, and is used as a driving element.

[0210] The color filter layer 1020 is located above the substrate 1010. As an example, the color filter layer 1020 may include a first color filter pattern 1022 corresponding to a first pixel region P1, a second color filter pattern 1024 corresponding to a second pixel region P2, and a third color filter pattern 1026 corresponding to a third pixel region P3. The first color filter pattern 1022 may be a blue color filter pattern, the second color filter pattern 1024 may be a green color filter pattern, and the third color filter pattern 1026 may be a red color filter pattern. For example, the first color filter pattern 1022 may include at least one of blue dye or blue pigment, the second color filter pattern 1024 may include at least one of green dye or green pigment, and the third color filter pattern 1026 may include at least one of red dye or red pigment.

[0211] A passivation layer 1050 is disposed above the thin-film transistor Tr and the color filter layer 1020. The passivation layer 1050 has a flat top surface and includes a drain contact hole 1052 that exposes the drain of the thin-film transistor Tr.

[0212] OLED D is disposed above passivation layer 1050 and corresponds to color filter layer 1020. OLED D includes a first electrode 1110 connected to the drain of thin-film transistor Tr, and a light-emitting layer 1120 and a second electrode 1130 sequentially disposed on the first electrode 1110. OLED D emits white light in the first to third pixel regions P1, P2 and P3.

[0213] For the first to third pixel regions P1, P2, and P3, the first electrode 1110 is formed independently, and the second electrode 1130 is formed integrally with respect to the first to third pixel regions P1, P2, and P3. The first electrode 1110 can be one of the anode and the cathode, and the second electrode 1130 can be the other of the anode and the cathode. Furthermore, the first electrode 1110 can be a transmissive (or semi-transmissive) electrode, and the second electrode 1130 can be a reflective electrode.

[0214] For example, the first electrode 1110 may be an anode and may include a transparent conductive oxide layer of a conductive material with a relatively high work function value, namely a transparent conductive oxide (TCO). The second electrode 1130 may be a cathode and may include a metallic material layer of a conductive material with a relatively low work function value, namely 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 include Al, Mg, Ca, Ag, alloys thereof (e.g., Mg-Ag), or combinations thereof.

[0215] A light-emitting layer 1120 is disposed on the first electrode 1110. The light-emitting layer 1120 includes at least two light-emitting portions that emit different colors. Each light-emitting portion may have a single-layer structure of EML. Alternatively, each light-emitting portion may include at least one of HIL, HTL, EBL, HBL, ETL, and EIL. Furthermore, the light-emitting layer 1120 may also include a CGL disposed between the light-emitting portions.

[0216] At least one of the at least two light-emitting parts may include EML1 containing a first compound and a second compound, and EML2 containing a third compound and a fourth compound. Alternatively, at least one of the at least two light-emitting parts may include EML1 containing a third compound and a fourth compound, and EML2 containing a first compound and a second compound.

[0217] A dam layer 1060 is disposed on the passivation layer 1050 to cover the edge of the first electrode 1110. The dam layer 1060 corresponds to each of the first to third pixel regions P1, P2, and P3 and exposes the center of the first electrode 1110. As described above, since the OLEDD emits white light in the first to third pixel regions P1, P2, and P3, the light-emitting layer 1120 can be formed as a universal layer without being separated in the first to third pixel regions P1, P2, and P3. The dam layer 1060 is formed to prevent current leakage from the edge of the first electrode 1110, and the dam layer 1060 can be omitted.

[0218] Furthermore, the organic light-emitting display device 1000 may also include an encapsulation film disposed on the second electrode 1130 to prevent external moisture from penetrating into the OLEDD. Additionally, the organic light-emitting display device 1000 may also include a polarizer disposed below the substrate 1010 to reduce external light reflection.

[0219] exist Figure 9 In the organic light-emitting display device 1000, the first electrode 1110 is a transmissive electrode, the second electrode 1130 is a reflective electrode, and the color filter layer 1020 is disposed between the substrate 1010 and the OLED D. That is, the organic light-emitting display device 1000 is a bottom-emitting type. Alternatively, the first electrode 1110 can be a reflective electrode, the second electrode 1120 can be a transmissive electrode (or a semi-transmissive electrode), and the color filter layer 1020 can be disposed above the OLED D in the organic light-emitting display device 1000 having a top-emitting structure.

[0220] In the organic light-emitting display device 1000, the OLED D located in the first to third pixel regions P1, P2 and P3 emits white light, and the white light passes through each of the first to third pixel regions P1, P2 and P3, so that blue, green and red are displayed in the first to third pixel regions P1, P2 and P3 respectively.

[0221] A color conversion film can be disposed between the OLED D and the color filter layer 1020. The color conversion film corresponds to the first to third pixel regions P1, P2, and P3, and includes a green conversion film, a red conversion film, and a blue conversion film, which can convert the white light emitted by the OLED D into green, red, and blue light, respectively. For example, the color conversion film may include quantum dots. Therefore, the organic light-emitting display device 1000 can further improve its color purity. Alternatively, the color conversion film can replace the color filter layer 1020.

[0222] Figure 10 This is a schematic cross-sectional view of an OLED illustrating yet another exemplary aspect of this disclosure. (See diagram below.) Figure 10 As shown, the OLED D4 includes a first electrode 1110 and a second electrode 1130 facing each other, and a light-emitting layer 1120 disposed between the first electrode 1110 and the second electrode 1130. The first electrode 1110 can be an anode, and the second electrode 1130 can be a cathode. For example, the first electrode 1100 can be a transmissive electrode, and the second electrode 1130 can be a reflective electrode.

[0223] The light-emitting layer 1120 includes a first light-emitting portion 1220, a second light-emitting portion 1320, and a third light-emitting portion 1420. The first light-emitting portion 1220 includes a lower EML 1240, the second light-emitting portion 1320 includes an intermediate EML 1340, and the third light-emitting portion 1420 includes an upper EML 1440. Furthermore, the light-emitting layer 1120 may also include a first charge-generating layer (CGL1) 1280 disposed between the first light-emitting portion 1220 and the second light-emitting portion 1320, and a second charge-generating layer (CGL2) 1380 disposed between the second light-emitting portion 1320 and the third light-emitting portion 1420. Therefore, the first light-emitting portion 1220, CGL1 1280, the second light-emitting portion 1320, CGL2 1380, and the third light-emitting portion 1420 are sequentially disposed on the first electrode 1110.

[0224] The first light-emitting portion 1220 may further include at least one of HIL 1250 disposed between the first electrode 1110 and the lower electrode 1240, a first HTL (HTL1) 1260 disposed between the lower EML 1240 and HIL 1250, and a first ETL (ETL1) 1270 disposed between the lower EML 1240 and CGL1 1280. Alternatively, the first light-emitting portion 1220 may further include at least one of a first EBL (EBL1) 1265 disposed between HTL 11260 and the lower EML 1240, and a first HBL (HBL1) 1275 disposed between the lower EML 1240 and ETL1 1270.

[0225] The second light-emitting unit 1320 may further include at least one of a second HTL (HTL2) 1360 disposed between CGL1 1280 and intermediate EML 1340 and a second ETL (ETL2) 1370 disposed between intermediate EML 1340 and CGL2 1380. Alternatively, the second light-emitting unit 1320 may further include a second EBL (EBL2) 1365 disposed between HTL2 1360 and intermediate EML 1340, and / or a second HBL (HBL2) 1375 disposed between intermediate EML 1340 and ETL2 1370.

[0226] The third light-emitting unit 1420 may further include at least one of the following: a third HTL (HTL3) 1460 disposed between CGL2 1380 and upper EML 1440; a third ETL (ETL3) 1470 disposed between upper EML 1440 and second electrode; and an EIL 1480 disposed between ETL3 1470 and second electrode 1130. Alternatively, the third light-emitting unit 1420 may further include a third EBL (EBL3) 1465 disposed between HTL3 1460 and upper EML 1440; and / or a third HBL (HBL3) 1475 disposed between upper EML 1440 and ETL3 1470.

[0227] CGL1 1280 is disposed between the first light-emitting part 1220 and the second light-emitting part 1320. That is, the first light-emitting part 1220 and the second light-emitting part 1320 are connected via CGL1 1280. CGL1 1280 may be a PN-connected CGL, which connects the first N-type CGL (N-CGL1) 1282 to the first P-type CGL (P-CGL1) 1284.

[0228] N-CGL1 1282 is disposed between ETL1 1270 and HTL2 1360, and P-CGL1 1284 is disposed between N-CGL1 1282 and HTL2 1360. N-CGL1 1282 transfers electrons to the lower EML 1240 of the first light-emitting part 1220, and P-CGL1 1284 transfers holes to the middle EML 1340 of the second light-emitting part 1320.

[0229] CGL2 1380 is disposed between the second light-emitting part 1320 and the third light-emitting part 1420. That is, the second light-emitting part 1320 and the third light-emitting part 1420 are connected by CGL2 1380. CGL2 1380 can be a PN-connected CGL, which connects the second N-type CGL (N-CGL2) 1382 and the second P-type CGL (P-CGL2) 1384.

[0230] N-CGL2 1382 is disposed between ETL2 1370 and HTL3 1460, and P-CGL2 1384 is disposed between N-CGL2 1382 and HTL3 1460. N-CGL2 1382 transfers electrons to the intermediate EML 1340 of the second light-emitting part 1320, and P-CGL2 1384 transfers holes to the upper EML 1440 of the third light-emitting part 1420.

[0231] In this respect, one of the lower, middle, and upper EMLs 1240, 1340, and 1440 can be a blue EML, another of the lower, middle, and upper EMLs 1240, 1340, and 1440 can be a green EML, and the third of the lower, middle, and upper EMLs 1240, 1340, and 1440 can be a red EML.

[0232] As an example, the top EML 1240 can be a blue EML, the middle EML 1340 can be a green EML, and the top EML 1440 can be a red EML. Alternatively, the bottom EML 1240 can be a red EML, the middle EML 1340 can be a green EML, and the top EML 1440 can be a blue EML. The following description will depict an OLED D3 where the bottom EML 1240 is a blue EML, the middle EML 1340 is a green EML, and the top EML 1440 is a red EML.

[0233] EML 1240 may include EML1 1242 containing a first compound and a second compound, and EML2 1244 containing a third compound and a fourth compound. Alternatively, EML1 1242 may contain a third compound and a fourth compound, while EML2 1244 may contain a first compound and a second compound.

[0234] The intermediate EML 1340 may include a host and a green dopant, and the upper EML 1440 may include a host and a red dopant. As an example, the host in each of the intermediate EML 1340 and the upper EML 1440 may include a first compound, and each of the green and red dopant may include at least one of green and red phosphorescent materials, green and red delayed fluorescence materials, and green and red fluorescent materials, respectively.

[0235] OLED D3 emits white light from each of the first to third pixel regions P1, P2, and P3, and the white light passes through the color filter layer 1020 correspondingly disposed in the first to third pixel regions P1, P2, and P3. Figure 9 Therefore, the organic light-emitting display device 1000 ( Figure 9 It can achieve full-color images.

[0236] Figure 11 This is a schematic cross-sectional view of an OLED illustrating yet another exemplary aspect of this disclosure. (See diagram below.) Figure 11 As shown, the OLED D5 includes a first electrode 1110 and a second electrode 1130 facing each other, and a light-emitting layer 1120A disposed between the first electrode 1110 and the second electrode 1130. The first electrode 1110 can be an anode, and the second electrode 1130 can be a cathode. For example, the first electrode 1100 can be a transmissive electrode, and the second electrode 1130 can be a reflective electrode.

[0237] The light-emitting layer 1120A includes a first light-emitting portion 1520 containing a lower EML 1540, a second light-emitting portion 1620 containing an intermediate EML 1640, and a third light-emitting portion 1720 containing an upper EML 1740. Furthermore, the light-emitting layer 1120A may further include a CGL1 1580 disposed between the first light-emitting portion 1520 and the second light-emitting portion 1620, and a CGL2 1680 disposed between the second light-emitting portion 1620 and the third light-emitting portion 1720. Therefore, the first light-emitting portion 1520, CGL1 1580, the second light-emitting portion 1620, CGL2 1680, and the third light-emitting portion 1720 are sequentially disposed on the first electrode 1110.

[0238] The first light-emitting portion 1520 may further include at least one of HIL 1550 disposed between the first electrode 1110 and the lower EML 1540, HTL1 1560 disposed between the lower EML 1540 and HIL 1550, and ETL1 1570 disposed between the lower EML 1540 and CGL1 1580. Alternatively, the first light-emitting portion 1520 may further include EBL1 1565 disposed between HTL1 1560 and the lower EML 1540, and / or HBL1 1575 disposed between the lower EML 1540 and ETL1 1570.

[0239] The intermediate EML 1640 of the second light-emitting portion 1620 includes a first layer 1642 and a second layer 1644. The first layer 1642 is adjacent to the first electrode 1110, and the second layer 1644 is adjacent to the second electrode 1130. Furthermore, the second light-emitting portion 1620 may also include at least one of HTL21660 disposed between CGL1 1580 and the intermediate EML 1640, and ETL2 1670 disposed between the intermediate EML 1640 and CGL2 1680. Alternatively, the second light-emitting portion 1620 may also include at least one of EBL2 1665 disposed between HTL2 1660 and the intermediate EML 1640, and HBL2 1675 disposed between the intermediate EML 1640 and ETL2 1670.

[0240] The third light-emitting unit 1720 may further include at least one of HTL3 1760 disposed between CGL2 1680 and upper EML 1740, ETL3 1770 disposed between upper EML 1740 and second electrode 1130, and EIL 1780 disposed between ETL3 1770 and second electrode 1130. Alternatively, the third light-emitting unit 1720 may further include EBL3 1765 disposed between HTL3 1760 and upper EML 1740, and / or HBL3 1775 disposed between upper EML 1740 and ETL3 1770.

[0241] CGL1 1580 is disposed between the first light-emitting part 1520 and the second light-emitting part 1620. That is, the first light-emitting part 1520 and the second light-emitting part 1620 are connected by CGL1 1580. CGL1 1580 can be a PN-connected CGL, which connects N-CGL1 1582 and P-CGL1 1584. N-CGL1 1582 is disposed between ETL1 1570 and HTL2 1660, and P-CGL1 1584 is disposed between N-CGL1 1582 and HTL2 1560.

[0242] CGL2 1680 is disposed between the second light-emitting part 1620 and the third light-emitting part 1720. That is, the second light-emitting part 1620 and the third light-emitting part 1720 are connected by CGL2 1680. CGL2 1680 can be a PN-connected CGL, which connects N-CGL2 1682 and P-CGL2 1684. N-CGL2 1682 is disposed between ETL2 1570 and HTL3 1760, and P-CGL2 1684 is disposed between N-CGL2 1682 and HTL3 1760.

[0243] In this respect, each of the lower EML 1540 and the upper EML 1740 may be a blue EML. In one exemplary aspect, the lower EML 1540 includes EML 11542 containing a first compound and a second compound, and EML 2 1544 containing a third compound and a fourth compound. The upper EML 1740 includes EML 1 1742 containing a first compound and a second compound, and EML 2 1744 containing a third compound and a fourth compound. Alternatively, each of EML 1 1542 and 1742 may include a third compound and a fourth compound, and each of EML 2 1544 and 1744 may include a first compound and a second compound.

[0244] In one exemplary aspect, each of the first and second compounds contained in EML1 1542 of lower EML 1540 may be independently the same as or different from each of the first and second compounds contained in EML1 1742 of upper EML 1740. Alternatively, each of the third and fourth compounds contained in EML2 1544 of lower EML 1540 may be independently the same as or different from each of the third and fourth compounds contained in EML2 1744 of upper EML 1740. In another alternative aspect, upper EML 1740 may include another compound that is different from at least one of the first to fourth compounds in lower EML 1540, so that the light emitted by upper EML 1740 is different from the light emitted from lower EML 1540, or the luminous efficiency of upper EML 1740 is different from the luminous efficiency of lower EML 1540.

[0245] One of the first layer 1642 and the second layer of intermediate EML 1640 can be a green EML, and the other of the first layer 1642 and the second layer 1644 of intermediate EML 1640 can be a red EML. The green EML and the red EML are set sequentially to form intermediate EML 1640.

[0246] As an example, the first layer 1642 of the red EML may include a host and a red dopant, and the second layer 1644 may include a host and a green dopant. As an example, the host in the first layer 1642 and the second layer 1644 may include a first compound, and each of the red and green dopant may respectively include at least one of red and green phosphorescent materials, red and green delayed fluorescence materials, and red and green fluorescent materials.

[0247] The OLED D5 emits white light in each of the first to third pixel regions P1, P2, and P3, and the white light passes through the color filter layer 1020 correspondingly disposed in the first to third pixel regions P1, P2, and P3. Figure 9 Therefore, the organic light-emitting display device 1000 ( Figure 9 It can achieve full-color images.

[0248] exist Figure 11 In this embodiment, the OLED D5 has a triple-layer structure comprising first to third light-emitting portions 1520, 1620, and 1720, which includes a lower EML 1540 and an upper EML 1740 serving as a blue EML. Alternatively, the OLED D5 may have a double-layer structure, which omits one of the first light-emitting portion 1520 and the third light-emitting portion 1720, each of which includes a lower EML 1540 and an upper EML 1740 serving as a blue EML.

[0249] Experimental Example 1: Measurement of PL Spectra of Luminescent Materials

[0250] The photoluminescence (PL) spectra of compounds 2-7 of Formula 4 and reference compounds 1 and 2 of the phosphorescent material, and compounds 4-5 and 4-1 of Formula 8 and reference compound 3 of the fluorescent material were measured. Compound 2-1 of Formula 2 (the main component) was mixed with each phosphorescent material at a weight ratio of 90:10 to form a thin film, and then the PL spectrum of the phosphorescent material was measured. Alternatively, compound 3-1 of Formula 3 (the main component) was mixed with each fluorescent material at a weight ratio of 98:2 to form a thin film, and then the PL spectrum of the fluorescent material was measured.

[0251] [Reference Compound]

[0252]

[0253] Table 1 below and Figure 12 and 13 The measurement results of the PL spectrum are illustrated. In Table 1, the first peak represents the emission peak with a shorter wavelength; the second peak represents the emission peak with a longer wavelength; and the peak intensity ratio refers to the ratio of the intensity of the second peak to the intensity of the first peak.

[0254] Table 1: PL spectra of phosphorescent and fluorescent materials

[0255]

[0256] Example 1: OLED Manufacturing

[0257] An OLED is fabricated in which the first EML (EML1) comprises compounds 1-1 and 2-7 and the second EML (EML2) comprises compounds 3-1 and 4-5. The ITO substrate is cleaned by UV-Ozone treatment before use and transferred to a vacuum chamber for deposition of the emissive layer. Subsequently, at 10... -7 Under vacuum conditions, the anode, light-emitting layer, and cathode are deposited in the following order by evaporation from a heated boat dish:

[0258] Anode (ITO, 7 nm) - APC (100 nm); HIL (NPD (90 wt%, F4-TCNQ (10 wt%) as P dopant, 10 nm); HTL (NPD, 123 nm); EBL (TAPC, 5 nm); EML1 (compound 1-1 (90 wt%), compound 2-7 (10 wt%), 15 nm); EML2 (compound 3-1 (98 wt%), compound 4-5 (2 wt%), 15 nm); HBL (B3PYMPM, 5 nm); ETL (PBPPhen, 25 nm); EIL (LiF, 2 nm); and cathode (Al (90 wt%), Mg (10 wt%), 12 nm).

[0259] After depositing the emissive layer and cathode, a CPL (capping layer, NPD, 70nm) is deposited on the cathode. The OLED is then transferred from the deposition chamber to a drying oven to form a thin film, followed by encapsulation of the OLED with UV-cured epoxy resin and a water-absorbing agent. The materials used in the emissive layer are shown below:

[0260]

[0261] Example 2: OLED Manufacturing

[0262] The OLED was manufactured using the same materials as in Example 1, except that compound 4-1 from Formula 8 was used instead of compound 4-5 as the fluorescent material in EML2.

[0263] Example 3: OLED Manufacturing

[0264] The OLED was manufactured using the same materials as in Example 1, except that EML1 (15nm) was modified to include compound 3-1 (98wt%) and compound 4-5 (2wt%), and EML2 (15nm) was modified to include compound 1-1 (90wt%) and compound 2-7 (10wt%).

[0265] Example 4: OLED Manufacturing

[0266] The OLED was fabricated using the same materials as in Example 1, except that EML1 (15nm) was modified to include compound 3-1 (98wt%) and compound 4-1 (2wt%), and EML2 (15nm) was modified to include compound 1-1 (90wt%) and compound 2-7 (10wt%).

[0267] Comparative Example 1 (Com.1): OLED Manufacturing

[0268] The OLED was fabricated using the same materials as in Example 1, except that the thickness of the HTL was modified to 128 nm and the EML was modified to a single EML (30 nm) comprising compound 3-1 (98 wt%) and compound 4-5 (2 wt%) instead of two EMLs.

[0269] Comparative Example 2 (Com.2): OLED Manufacturing

[0270] The OLED was fabricated using the same materials as in Example 1, except that the thickness of the HTL was modified to 128 nm and the EML was modified to a single EML (30 nm) comprising compound 3-1 (98 wt%) and compound 4-1 (2 wt%) instead of two EMLs.

[0271] Comparative Example 3 (Com.3): OLED Manufacturing

[0272] The OLED was fabricated using the same materials as in Example 1, except that the thickness of the HTL was modified to 135 nm and the EML was modified to a single EML (30 nm) comprising compound 3-1 (98 wt%) and reference compound 1 (2 wt%) instead of two EMLs.

[0273] Comparative Example 4 (Com.4): OLED Manufacturing

[0274] The OLED was fabricated using the same materials as in Example 1, except that the thickness of the HTL was modified to 128 nm and the EML was modified to a single EML (30 nm) comprising compound 1-1 (90 wt%) and compound 2-7 (10 wt%) instead of two EMLs.

[0275] Comparative Example 5 (Com.5): OLED Manufacturing

[0276] The OLED was fabricated using the same materials as in Example 1, except that the thickness of the HTL was modified to 128 nm, and reference compound 3 was used instead of compounds 4-5 as the fluorescent material in EML2.

[0277] Comparative Example 6 (Com.5): OLED Manufacturing

[0278] The OLED was fabricated using the same materials as in Example 1, except that the thickness of the HTL was modified to 128 nm, and the EML was modified to consist of a single EML (30 nm) comprising compound 1-1 (90 wt%) and reference compound 1 (10 wt%) instead of two EMLs.

[0279] Comparative Example 7 (Com.7): OLED Manufacturing

[0280] The OLED was fabricated using the same materials as in Example 1, except that the thickness of the HTL was modified to 128 nm, and reference compound 1 was used to replace compounds 2-7 as phosphorescent materials in the EML, and reference compound 3 was used to replace compounds 4-5 as fluorescent materials in the EML2.

[0281] Comparative Example 8 (Com.8): OLED Manufacturing

[0282] The OLED was fabricated using the same materials as in Example 1, except that the thickness of the HTL was modified to 128 nm, and the EML was modified to consist of a single EML (30 nm) comprising compound 1-1 (90 wt%) and reference compound 2 (10 wt%) instead of two EMLs.

[0283] Comparative Example 9 (Com.9): OLED Manufacturing

[0284] The OLED was manufactured using the same materials as in Example 1, except that reference compound 2 was used instead of compounds 2-7 as the phosphorescent material in EML1.

[0285] Comparative Example 10 (Com.10): OLED Manufacturing

[0286] The OLED was fabricated using the same materials as in Example 1, except that reference compound 2 was used instead of compounds 2-7 as the phosphorescent material in EML1, and compound 4-1 was used instead of compounds 4-5 as the fluorescent material in EML2.

[0287] Comparative Example 11 (Com.11): OLED Manufacturing

[0288] The OLED was fabricated using the same materials as in Example 1, except that the thickness of the HTL was modified to 130 nm, and reference compound 2 was used instead of compounds 2-7 as the phosphorescent material in the EML, and reference compound 3 was used instead of compounds 4-5 as the fluorescent material in EML2.

[0289] Comparative Example 12 (Com.12): OLED Manufacturing

[0290] The OLED was fabricated using the same materials as in Example 1, except that EML1 (15nm) was modified to include compound 3-1 (98wt%) and compound 4-5 (2wt%), and EML2 (15nm) was modified to include compound 1-1 (90wt%) and reference compound 1 (10wt%).

[0291] Comparative Example 13 (Com.13): OLED Manufacturing

[0292] The OLED was fabricated using the same materials as in Example 1, except that the thickness of the HTL was modified to 125 nm, and EML1 (15 nm) was modified to include compound 3-1 (98 wt%) and compound 4-1 (2 wt%), and EML2 (15 nm) was modified to include compound 1-1 (90 wt%) and reference compound 1 (10 wt%).

[0293] Experiment Example 2: Measurement of OLED Emissivity

[0294] The 9mm-sized samples manufactured in Examples 1-4 (Ex. 1-4) and Comparative Examples 1-13 (Ref. 1-13) 2Each OLED with a light-emitting area was connected to an external power supply, and the light-emitting characteristics of all diodes were evaluated at room temperature using a constant current source (KEITHLEY) and a PR650 photometer. Specifically, the driving voltage (V), current efficiency (cd / A), color coordinates (CIEx, CIEy), blue index (BI, cd / A divided by CIEy), and relative luminous lifetime (T95) compared to phosphorescent devices were measured (each of Examples 1-4 and Comparative Examples 5 was compared to Comparative Example 4; each of Comparative Examples 7 and Comparative Examples 12-13 was compared to Comparative Example 6; each of Comparative Examples 9-11 was compared to Comparative Example 8). Furthermore, the PL and electroluminescence (EL) spectra of the phosphorescent and fluorescent materials of each OLED were measured. The measurement results of the OLEDs are shown in Table 2 below. Figure 14-19 middle:

[0295] Table 2: Luminescent properties of OLEDs

[0296]

[0297]

[0298] As shown in Table 2 and Figure 14-19 As shown, the OLEDs fabricated in Comparative Examples 1-2, where only fluorescent materials were used in the EML, exhibited low luminous efficiency and poor BI. The OLEDs fabricated in Comparative Examples 4, 6, and 8, where only phosphorescent materials were used in the EML, exhibited shorter luminous lifetimes. In the OLEDs fabricated in Comparative Examples 9-13, where reference compounds 1-2, which exhibited higher intensity relative to the first peak and second peak in the PL spectrum and a wider FWQM, were applied to the EML, CIEy increased. Compared to the OLEDs fabricated in Comparative Examples 1-3, where only fluorescent materials were used in the EML, the BI value of the OLEDs fabricated in Comparative Examples 9-13 was lower, resulting in almost no color improvement effect.

[0299] Furthermore, in OLEDs manufactured in Comparative Examples 5, 7, and 11, where the maximum PL spectrum of reference compound 3, which is significantly different from that of the phosphorescent material (Comparative Example 5, Reference Compounds 1-2), was used as the fluorescent material, the BI value decreased significantly with a substantial increase in CIEy. In particular, the lifetime of the OLED manufactured in Comparative Example 5 was significantly reduced compared to the OLEDs manufactured in Examples 1-2.

[0300] Conversely, compared to the OLEDs manufactured in Comparative Examples 1-2, the OLEDs manufactured in Examples 1-4, in which the same fluorescent material as that in Comparative Examples 1-2 was applied in the EML, exhibited a significantly improved luminous efficiency of 71.4%, with almost no change in the CIEy value. Due to the significantly improved BI value, the OLEDs manufactured in Examples 1-4 achieved a deep blue color and excellent color purity. Furthermore, compared to the OLEDs manufactured in Comparative Example 5, the luminous lifetime of the OLEDs manufactured in Examples 1-4 was significantly improved. In particular, in the OLEDs manufactured in Examples 1-2, in which fluorescent materials, each having a shorter maximum PL peak wavelength than the phosphorescent material and a relatively narrow FWQM, were introduced into the EML2 relatively adjacent to the cathode, the CIEy value remained almost unchanged, and thus, the BI value and luminous lifetime were further increased.

[0301] Comparative Example 14 (Com. 14): OLED Manufacturing

[0302] The OLED was fabricated using the same materials as in Example 1, except that the EML was modified to consist of a single EML (30 nm) comprising compound 1-1 (88 wt%), compound 2-7 (10 wt%), and compound 4-5 (2 wt%), instead of two EMLs.

[0303] Comparative Example 15 (Com.15): OLED Manufacturing

[0304] The OLED was fabricated using the same materials as in Example 1, except that the EML was modified to consist of a single EML (30 nm) comprising compound 1-1 (88 wt%), compound 2-7 (10 wt%), and compound 4-1 (2 wt%), instead of two EMLs.

[0305] Comparative Example 16 (Com.16): OLED Manufacturing

[0306] The OLED was fabricated using the same materials as in Example 1, except that the EML was modified to consist of a single EML (30 nm) comprising compound 1-1 (88 wt%), reference compound 1 (10 wt%), and compound 4-5 (2 wt%), instead of two EMLs.

[0307] Comparative Example 17 (Com.17): OLED Manufacturing

[0308] The OLED was fabricated using the same materials as in Example 1, except that the EML was modified to consist of a single EML (30 nm) comprising compound 1-1 (88 wt%), reference compound 1 (10 wt%), and compound 4-1 (2 wt%), instead of two EMLs.

[0309] Experiment Example 3: Measurement of OLED Emissivity

[0310] The luminescence characteristics of each OLED in Examples 1-4 and Comparative Examples 6 and 14-17 (Ref. 6 and 14-17) were measured using the same procedure as in Experimental Example 1. The luminescence lifetime of the OLEDs in Comparative Examples 14-15 was compared with that of the OLED in Comparative Example 4, and the luminescence lifetime of the OLEDs in Comparative Examples 16-17 was compared with that of the OLED in Comparative Example 6. The measurement results of the OLEDs are shown in Table 3 below:

[0311] Table 3: Luminescent properties of OLEDs

[0312]

[0313] In Comparative Examples 14-17, a single EML comprises a first compound with a high triplet energy level, a phosphorescent material, and a fluorescent material. In a single EML, the luminescence lifetime of the OLED in Comparative Examples 14-17 is significantly reduced because the concentration of triplet excitons generated in the phosphorescent material remains high, and the triplet excitons do not transfer to other adjacent molecules and degrade the fluorescent material. Conversely, when the EML is divided into a phosphorescent layer and a fluorescent layer as in Examples 1-4, the concentration of triplet excitons in the phosphorescent layer decreases due to exciton dispersion. In this case, high-energy triplet exciton quenching, such as triplet-triplet annihilation (TTA) or triplet-polaron annihilation, can be prevented in the phosphorescent layer. Furthermore, the fluorescent layer contains a third compound with a low excitation triplet energy level as the host. In this case, the lower triplet energy level in the fluorescent layer improves exciton stability, thus enabling the OLED to achieve a very excellent luminescence lifetime.

[0314] It will be apparent to those skilled in the art that various modifications and variations can be made to the OLED and organic light-emitting devices including OLEDs of this disclosure without departing from the technical spirit or scope of this disclosure. Therefore, this disclosure is intended to cover modifications and variations thereof, provided they fall within the scope of the appended claims and their equivalents.

Claims

1. An organic light-emitting diode, comprising: First electrode; The second electrode facing the first electrode; and A light-emitting layer disposed between the first electrode and the second electrode and comprising at least one layer of light-emitting material. The at least one luminescent material layer includes a first luminescent material layer and a second luminescent material layer disposed adjacent to the first luminescent material layer. The first luminescent material layer comprises a first compound having the structure of Formula 1 and a second compound having the structure of Formula 3, and The second luminescent material layer comprises a third compound having the structure of Formula 5 and a fourth compound having the structure of Formula 7. [Formula 1] In Equation 1, R 1 and R 2 Each is independently an unsubstituted or substituted carbazolyl or an unsubstituted or substituted carbazolinyl; R 3 It is hydrogen, cyano, unsubstituted or substituted C1-C 20 Alkyl, unsubstituted or substituted C6-C 30 aryl, or unsubstituted or substituted C3-C 30 Mixed aromatics; Z is N or CR 4 , where R 4 Hydrogen, unsubstituted or substituted C1-C 10 Alkyl, unsubstituted or substituted C6-C 30 aryl, or unsubstituted or substituted C3-C 30 heteroaryl; and L 1 and L 2 Each is independently a single bond, unsubstituted or substituted C6-C 30 Aryl styrene, or unsubstituted or substituted C3-C 30 Mixed aromatic base, [Formula 3] In Equation 3, R 11 To R 14 Each is independently hydrogen, halogen, cyano, unsubstituted or substituted C1-C 10 Alkyl, unsubstituted or substituted C1-C 10 Alkylamino, unsubstituted or substituted C6-C 30 Aryl, unsubstituted or substituted C3-C 30 Heteroaryl, or unsubstituted or substituted adamantyl, [Formula 5] In Equation 5, R 21 and R 22 Each is independently hydrogen, unsubstituted or substituted C1-C 20 Alkyl, unsubstituted or substituted C6-C 30 aryl, or unsubstituted or substituted C3-C 30 heteroaryl; and R 23 and R 24 Each is independently unsubstituted or substituted C6-C 30 aryl, or unsubstituted or substituted C3-C 30 Mixed aromatics, [Formula 7] In Equation 7, R 31 To R 33 Each is independently hydrogen, halogen, cyano, unsubstituted or substituted C1-C 20 Alkyl, unsubstituted or substituted C6-C 30 Aryl, unsubstituted or substituted C3-C 30 heteroaryl, or unsubstituted or substituted C6-C 30 arylamino; R 34 and R 35 Each is independently halogenated, cyano, unsubstituted or substituted C1-C. 20 Alkyl, unsubstituted or substituted C6-C 30 Aryl, unsubstituted or substituted C3-C 30 heteroaryl, or unsubstituted or substituted C6-C 30 arylamino, where R is an integer of 2 or greater when m is 2. 34 They are either the same or different from each other, and when n is an integer of 2 or greater, each R 35 They are the same or different from each other; and m and n are each an independent integer from 0 to 5.

2. The organic light-emitting diode according to claim 1, wherein the second light-emitting material layer is disposed between the first light-emitting material layer and the second electrode.

3. The organic light-emitting diode according to claim 1, wherein the excited triplet energy level of the first compound is higher than the excited triplet energy level of the second compound.

4. The organic light-emitting diode according to claim 1, wherein the excited triplet energy level of the fourth compound is higher than that of the excited triplet energy level of the third compound.

5. The organic light-emitting diode according to claim 1, wherein the excited singlet state energy level of the third compound is higher than that of the fourth compound.

6. The organic light-emitting diode according to claim 1, wherein the excited singlet energy level of the fourth compound is higher than the excited triplet energy level of the third compound.

7. The organic light-emitting diode of claim 1, wherein the ratio of the intensity of the emission peak formed by the second compound in a relatively long wavelength range to the intensity of the maximum emission peak is between about 0.20 and about 0.

65.

8. The organic light-emitting diode according to claim 1, wherein the full width at one-quarter peak (FWQM) of the fourth compound is narrower than that of the second compound.

9. The organic light-emitting diode according to claim 1, wherein the first compound is selected from:

10. The organic light-emitting diode according to claim 2, wherein the second compound is selected from:

11. The organic light-emitting diode according to claim 1, wherein the third compound is selected from:

12. The organic light-emitting diode according to claim 1, wherein the fourth compound is selected from:

13. The organic light-emitting diode according to claim 1, wherein the light-emitting layer comprises a first light-emitting portion disposed between the first electrode and the second electrode, a second light-emitting portion disposed between the first light-emitting portion and the second electrode, and a first charge-generating layer disposed between the first light-emitting portion and the second light-emitting portion, and At least one of the first light-emitting part and the second light-emitting part includes the light-emitting material layer.

14. The organic light-emitting diode according to claim 13, wherein the first light-emitting portion comprises the light-emitting material layer.

15. The organic light-emitting diode according to claim 13, wherein the second light-emitting portion comprises a blue fluorescent light-emitting material layer, a blue phosphorescent light-emitting material layer, a blue delayed fluorescent light-emitting material layer, or the light-emitting material layer.

16. The organic light-emitting diode according to claim 13, wherein the light-emitting layer further comprises a third light-emitting portion disposed between the second light-emitting portion and the second electrode, and a second charge-generating layer disposed between the second light-emitting portion and the third light-emitting portion.

17. The organic light-emitting diode according to claim 16, wherein at least one of the first light-emitting portion and the third light-emitting portion comprises the light-emitting material layer.

18. The organic light-emitting diode according to claim 16, wherein the second light-emitting portion comprises at least one of a green light-emitting material layer, a yellow-green light-emitting material layer, and a red light-emitting material layer.

19. An organic light-emitting device, comprising: substrate; and the organic light-emitting diode according to claim 1 disposed on the substrate.

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