Organic light-emitting diode and organic light-emitting device having the organic light-emitting diode

Abstract

An organic light-emitting diode (OLED) includes: a first electrode; a second electrode facing the first electrode; and a first light-emitting material layer, the first light-emitting material layer comprising a first compound and a second compound and disposed between the first electrode and the second electrode. The emission spectrum of the first compound and the absorption spectrum of the second compound have a large overlap. An organic light-emitting device may include the aforementioned organic light-emitting diode.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2021-0124009, filed in Korea on September 16, 2021, which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure relates to a light-emitting diode, and more particularly to an organic light-emitting diode having high luminous efficiency and providing light emission over a short wavelength range, and an organic light-emitting device including the organic light-emitting diode. Background Technology

[0004] Recently, there has been an increasing demand for flat panel display devices with a small footprint. Among flat panel display devices, organic light-emitting diode (OLED) and organic electroluminescent devices (OLEDs) technologies have developed rapidly.

[0005] OLEDs emit light by injecting electrons from the cathode (which acts as the electron injection electrode) and holes from the anode (which acts as the hole injection electrode) into the light-emitting material layer, combining the electrons and holes to generate excitons, and then transitioning the excitons from the excited state to the ground state.

[0006] Fluorescent materials can be used as light emitters in OLEDs. However, the luminescence efficiency of fluorescent materials is limited because only singlet excitons participate in the emission. Summary of the Invention

[0007] Therefore, embodiments of this disclosure relate to an OLED and an organic light-emitting device that substantially eliminate one or more problems associated with the limitations and disadvantages of the prior art.

[0008] One object of this disclosure is to provide OLEDs and organic light-emitting devices with reduced full width at half maximum (FWHM) and improved luminous efficiency by providing a first compound as a delayed fluorescence material and a second compound as a fluorescence material in a single luminescent material layer or adjacent luminescent material layers.

[0009] Another objective of this disclosure is to provide OLEDs and organic light-emitting devices with improved luminous efficiency by increasing the overlap between the emission spectrum of the first compound and the absorption spectrum of the second compound.

[0010] Other features and aspects will be set forth in the following description, and some of these features and aspects will become apparent from the description or may be learned by practicing the inventive concept provided herein. Other features and aspects of the inventive concept may be realized and obtained by means of structures particularly pointed out in or derived therefrom in the written description, as well as by the claims and drawings herein.

[0011] To achieve these and other advantages according to the purposes of embodiments of this disclosure, as described herein, one aspect of this disclosure is an organic light-emitting diode (OLED) comprising: a first electrode; a second electrode facing the first electrode; and a first light-emitting material layer comprising a first compound and a second compound and disposed between the first electrode and the second electrode, wherein the first compound is represented by Formula 1-1: [Formula 1-1] Wherein X1 is one of a single bond, C(R6)2, NR7, O, and S, wherein Y is selected from the group consisting of: cyano (-CN), nitro (-NO2), halogen, C1 to C20 alkyl substituted with at least one of cyano, nitro, and halogen, C6 to C30 aryl substituted with at least one of cyano, nitro, and halogen, and C3 to C40 heteroaryl substituted with at least one of cyano, nitro, and halogen, wherein R1 to R7 are each independently selected from the group consisting of: deuterium, tritium, substituted or unsubstituted. The second compound is formed by C1 to C20 alkyl groups, substituted or unsubstituted C6 to C30 aryl groups, and substituted or unsubstituted C3 to C40 heteroaryl groups, or by two adjacent R1 to R7 groups forming an aromatic ring or heteroaryl ring, wherein L is a C6 to C30 aryl group, wherein a1 and a2 are each independently an integer from 0 to 5, wherein a3 is an integer from 0 to 3, wherein a4 and a5 are each independently an integer from 0 to 4, wherein n1 is 1 or 2, and n2 is an integer from 1 to 5, wherein the second compound is represented by Formula 2-1: [Formula 2-1]

[0012] R11 to R14 are each independently selected from the group consisting of: deuterium, tritium, substituted or unsubstituted C1 to C20 alkyl, substituted or unsubstituted C6 to C30 aryl, and substituted or unsubstituted C3 to C40, or two adjacent R11 to R14 are linked to form an aromatic ring or heteroaromatic ring, wherein R21 to R28, R31 to R38, and R41 to R48 are each independently selected from the group consisting of: hydrogen, deuterium, tritium, substituted or unsubstituted C1 to C20 alkyl, substituted or unsubstituted C6 to C30 aryl, and substituted or unsubstituted C3 to C40 heteroaromatic, wherein R29, R30, R39, R40, R49 and R50 are each independently selected from the group consisting of: hydrogen, deuterium, tritium, substituted or unsubstituted C1 to C20 alkyl, substituted or unsubstituted C6 to C30 aryl and substituted or unsubstituted C3 to C40 heteroaryl, or at least one pair of R29 and R30, R39 and R40 and R49 and R50 connected to each other to form a ring, wherein m1 to m3 are each independently 0 or 1, and at least one of m1 to m3 is 1, and wherein b1 and b4 are each independently integers from 0 to 4, and b2 and b3 are each independently integers from 0 to 3.

[0013] Another aspect of this disclosure is an organic light-emitting device, comprising: a substrate; the aforementioned organic light-emitting diode disposed on or above the substrate; and an encapsulation film covering the organic light-emitting diode.

[0014] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory, and are intended to provide further explanation of the claimed inventive concept. Attached Figure Description

[0015] The accompanying drawings are included to provide a further understanding of this disclosure, are incorporated in and constitute a part of this application, illustrate embodiments of this disclosure, and, together with the description, serve to explain the principles of this disclosure.

[0016] Figure 1 This is a schematic circuit diagram of the organic light-emitting display device disclosed herein.

[0017] Figure 2 This is a schematic cross-sectional view of an organic light-emitting display device according to a first embodiment of the present disclosure.

[0018] Figure 3 This is a schematic cross-sectional view of an OLED according to a second embodiment of the present disclosure.

[0019] Figure 4 This is a schematic diagram illustrating the relationship between the emission spectrum of delayed fluorescent materials and the absorption spectrum of fluorescent materials in OLEDs.

[0020] Figure 5 This is a schematic diagram showing the relationship between the emission spectrum of the first compound and the absorption spectrum of the second compound in an OLED according to the second embodiment of this disclosure.

[0021] Figure 6 This is a schematic cross-sectional view of an OLED according to a third embodiment of the present disclosure.

[0022] Figure 7 This is a schematic cross-sectional view of an OLED according to the fourth embodiment of the present disclosure.

[0023] Figure 8 This is a schematic cross-sectional view of an OLED according to the fifth embodiment of the present disclosure.

[0024] Figure 9 This is a schematic cross-sectional view of an organic light-emitting display device according to the sixth embodiment of this disclosure.

[0025] Figure 10 This is a schematic cross-sectional view of an OLED according to the seventh embodiment of the present disclosure.

[0026] Figure 11 This is a schematic cross-sectional view of an organic light-emitting display device according to the eighth embodiment of this disclosure.

[0027] Figure 12 This is a schematic cross-sectional view of an OLED according to the ninth embodiment of this disclosure.

[0028] Figure 13 This is a schematic cross-sectional view of an OLED according to the tenth embodiment of the present disclosure. Detailed Implementation

[0029] Reference will now be made in detail to some embodiments and preferred implementations shown in the accompanying drawings.

[0030] This disclosure relates to an OLED comprising a delayed fluorescence material and a fluorescent material in a single light-emitting material layer or adjacent light-emitting material layers, and an organic light-emitting device including the OLED. The emission spectrum of the delayed fluorescence material matches the absorption spectrum of the fluorescent material. For example, the organic light-emitting device may be an organic light-emitting display device or an organic lighting device. As an example, an organic light-emitting display device comprising the OLED of this disclosure will be primarily described.

[0031] Figure 1 This is a schematic circuit diagram of the organic light-emitting display device disclosed herein.

[0032] like Figure 1As shown, the organic light-emitting display device includes a gate line GL, a data line DL, a power line PL, a switching thin-film transistor (TFT) Ts, a driving TFT Td, a storage capacitor Cst, and an OLED D. The gate line GL and the data line DL intersect each other to define a pixel region P. The pixel region may include a red pixel region, a green pixel region, and a blue pixel region.

[0033] The switching TFT Ts is connected to the gate line GL and the data line DL, and the driving TFT Td and the storage capacitor Cst are connected to the switching TFT Ts and the power line PL. The OLED D is connected to the driving TFT Td.

[0034] In an organic light-emitting display device, when the switching TFT Ts is turned on by the gate signal applied through the gate line GL, the data signal from the data line DL is applied to the gate of the driving TFT Td and the electrodes of the storage capacitor Cst.

[0035] When the driving TFT Td is turned on by a data signal, current is supplied from the power line PL to the OLED D. As a result, the OLED D emits light. In this case, when the driving TFT Td is turned on, the current level applied from the power line PL to the OLED D is determined so that the OLED D can produce grayscale.

[0036] The storage capacitor Cst is used to maintain the gate voltage of the driving TFT Td when the switching TFT Ts is turned off. Therefore, even if the switching TFT Ts is turned off, the current level applied to the OLED D from the power supply line PL is maintained until the next frame.

[0037] As a result, the organic light-emitting display device displays the desired image.

[0038] Figure 2 This is a schematic cross-sectional view of an organic light-emitting display device according to a first embodiment of the present disclosure.

[0039] like Figure 2 As shown, the organic light-emitting display device 100 includes a substrate 110, a TFT Tr, and an OLEDD connected to the TFT Tr.

[0040] The substrate 110 can be a glass substrate or a plastic substrate. For example, the substrate 110 can be a polyimide substrate.

[0041] A buffer layer 122 is formed on the substrate, and a TFT Tr is formed on the buffer layer 122. The buffer layer 122 can be omitted.

[0042] Semiconductor layer 120 is formed on buffer layer 122. Semiconductor layer 120 may include oxide semiconductor material or polysilicon.

[0043] When the semiconductor layer 120 comprises an oxide semiconductor material, a light-shielding pattern (not shown) can be formed beneath the semiconductor layer 120. Light reaching the semiconductor layer 120 is shielded or blocked by the light-shielding pattern, thereby preventing thermal degradation of the semiconductor layer 120. On the other hand, when the semiconductor layer 120 comprises polysilicon, impurities can be doped onto both sides of the semiconductor layer 120.

[0044] A gate insulating layer 124 is formed on the semiconductor layer 120. The gate insulating layer 124 may be formed of an inorganic insulating material such as silicon oxide or silicon nitride.

[0045] A gate 130, formed of a conductive material such as metal, is formed on the gate insulating layer 124 to correspond to the center of the semiconductor layer 120.

[0046] exist Figure 2 In this configuration, the gate insulating layer 124 is formed over the entire surface of the substrate 110. Alternatively, the gate insulating layer 124 may be patterned to have the same shape as the gate 130.

[0047] An interlayer insulating layer 132, formed of an insulating material, is formed on the gate 130. The interlayer insulating layer 132 may be formed of an inorganic insulating material (e.g., silicon oxide or silicon nitride) or an organic insulating material (e.g., benzocyclobutene or photoacrylic).

[0048] The interlayer insulating layer 132 includes a first contact hole 134 and a second contact hole 136 exposing both sides of the semiconductor layer 120. The first contact hole 134 and the second contact hole 136 are located on both sides of the gate 130 and spaced apart from the gate 130.

[0049] The first contact hole 134 and the second contact hole 136 are formed through the gate insulating layer 124. Alternatively, when the gate insulating layer 124 is patterned to have the same shape as the gate 130, the first contact hole 134 and the second contact hole 136 are formed only through the interlayer insulating layer 132.

[0050] Source 144 and drain 146, formed of conductive material such as metal, are formed on interlayer insulating layer 132.

[0051] The source 144 and drain 146 are spaced apart from each other relative to the gate 130 and contact the two sides of the semiconductor layer 120 through the first contact hole 134 and the second contact hole 136, respectively.

[0052] Semiconductor layer 120, gate 130, source 144, and drain 146 constitute TFT Tr. TFT Tr serves as a driving element. That is, TFT Tr is the driving element. Figure 1 TFT Td.

[0053] In the TFT Tr, the gate 130, source 144, and drain 146 are located above the semiconductor layer 120. That is, the TFT Tr has a coplanar structure.

[0054] Alternatively, in the TFT Tr, the gate can be located below the semiconductor layer, and the source and drain can be located above the semiconductor layer, allowing the TFT Tr to have an inverted interleaved structure. In this case, the semiconductor layer may include amorphous silicon.

[0055] Although not shown, the gate line and data line intersect each other to define a pixel area, and a switching TFT is formed to connect to the gate line and the data line. The switching TFT is connected to the TFT Tr, which serves as a driving element. Furthermore, a power line, which can be formed parallel to and spaced apart from one of the gate line and the data line, and a storage capacitor for maintaining the voltage of the gate of the TFT Tr during a frame can be further formed.

[0056] A planarization layer 150 is formed on the entire surface of the substrate 110 to cover the source 144 and the drain 146. The planarization layer 150 provides a flat top surface and has a drain contact hole 152 that exposes the drain 146 of the TFT Tr.

[0057] The OLED D is disposed on the planarization layer 150 and includes a first electrode 210 connected to the drain 146 of the TFT Tr, an emissive layer 220, and a second electrode 230. The emissive layer 220 and the second electrode 230 are stacked sequentially on the first electrode 210. The OLED D is located in each of the red, green, and blue pixel regions and emits red light, green light, and blue light, respectively.

[0058] First electrodes 210 are formed in each pixel region. The first electrode 210 can be an anode and can be formed of a conductive material with a relatively high work function, such as a transparent conductive oxide (TCO). For example, the first electrode 210 can be formed of indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), tin oxide (SnO), zinc oxide (ZnO), indium copper oxide (ICO), or aluminum zinc oxide (Al:ZnO, AZO).

[0059] When the organic light-emitting display device 100 of this disclosure operates in a bottom-emitting mode, the first electrode 210 may have a single-layer structure of a transparent conductive oxide layer. Alternatively, when the organic light-emitting display device 100 of this disclosure operates in a top-emitting mode, a reflective electrode or reflective layer may be formed above and / or below the transparent conductive oxide layer. For example, the reflective electrode or reflective layer may be formed of a silver (Ag) or aluminum-palladium-copper (APC) alloy. In a top-emitting OLED, the first electrode 210 may have an ITO / Ag / ITO or ITO / APC / ITO structure.

[0060] Furthermore, a dam layer 160 is formed on the planarization layer 150 to cover the edge of the first electrode 210. That is, the dam layer 160 is located at the boundary of the pixel region and exposed at the center of the first electrode 210 in the pixel region.

[0061] The light-emitting layer 220, serving as a light-emitting unit, is formed on the first electrode 210. The light-emitting layer 220 may have a monolayer structure comprising a light-emitting material layer (EML). Alternatively, the light-emitting layer 220 may further comprise at least one of a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), a hole blocking layer (HBL), an electron transport layer (ETL), and an electron injection layer (EIL), thus having a multilayer structure. Furthermore, two or more light-emitting layers may be spaced apart from each other, allowing the OLED D to have a series structure.

[0062] The second electrode 230 is formed above the substrate 110 on which the light-emitting layer 220 is formed. The second electrode 230 covers the entire surface of the display area and can be formed of a conductive material with a relatively low work function to serve as a cathode. For example, the second electrode 230 can be formed of aluminum (Al), magnesium (Mg), calcium (Ca), silver (Ag), or alloys thereof, such as Mg-Ag alloy (MgAg). In the top-emitting organic light-emitting display device 100, the second electrode 230 can have a thin profile and be transparent (or translucent).

[0063] Although not shown, the organic light-emitting display device 100 may include color filters corresponding to the red, green, and blue pixel regions. For example, when an OLED D having a series structure and emitting white light is formed to all the red, green, and blue pixel regions, a red color filter pattern, a green color filter pattern, and a blue color filter pattern may be formed in the red, green, and blue pixel regions, respectively, thereby providing full-color display.

[0064] When the organic light-emitting display device 100 operates in a bottom-emitting mode, the color filter can be disposed between the OLED D and the substrate 110, for example, between the interlayer insulating layer 132 and the planarization layer 150. Alternatively, when the organic light-emitting display device 100 operates in a top-emitting mode, the color filter can be disposed above the OLED D, for example, above the second electrode 230.

[0065] An encapsulation film (or encapsulation layer) 170 is formed on the second electrode 230 to prevent moisture from penetrating into the OLED D. The encapsulation film 170 includes, but is not limited to, a first inorganic insulating layer 172, an organic insulating layer 174, and a second inorganic insulating layer 176 stacked in sequence.

[0066] The organic light-emitting display device 100 may further include a polarizing plate (not shown) for reducing ambient light reflection. For example, the polarizing plate may be a circular polarizing plate. In a bottom-emitting organic light-emitting display device 100, the polarizing plate may be located below the substrate 110. Alternatively, in a top-emitting organic light-emitting display device 100, the polarizing plate may be located above or above the encapsulation film 170.

[0067] Furthermore, in the top-emitting organic light-emitting display device 100, a cover window (not shown) can be attached to the encapsulation film 170 or the polarizing plate. In this case, the substrate 110 and the cover window have flexible properties, thereby providing a flexible organic light-emitting display device.

[0068] Figure 3 This is a schematic cross-sectional view of an OLED according to a second embodiment of the present disclosure.

[0069] like 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 between them. The light-emitting layer 220 includes a light-emitting material layer (EML) 240. Figure 2 The organic light-emitting display device 100 may include a red pixel area, a green pixel area and a blue pixel area, with the OLED D1 located in the green pixel area.

[0070] The first electrode 210 can be an anode, and the second electrode 230 can be a cathode. One of the first electrode 210 and the second electrode 230 can be a transparent electrode (or a semi-transparent electrode), and the other of the first electrode 210 and the second electrode 230 can be a reflective electrode.

[0071] The light-emitting layer 220 further includes at least one of a hole transport layer (HTL) 260 between the first electrode 210 and the EML 240 and an electron transport layer (ETL) 270 between the second electrode 230 and the EML 240.

[0072] Furthermore, the light-emitting layer 220 may further include at least one of a hole injection layer (HIL) 250 between the first electrode 210 and HTL 260 and an electron injection layer (EIL) 280 between the second electrode 230 and ETL 270.

[0073] Furthermore, the light-emitting layer 220 may further include at least one of an electron blocking layer (EBL) 265 between HTL 260 and EML 240 and a hole blocking layer (HBL) 275 between EML 240 and ETL 270.

[0074] For example, HIL 250 may include at least one compound selected from the group consisting of: 4,4'4"-tris(3-methylphenylamino)triphenylamine (MTDATA), 4,4',4"-tris(N,N-diphenylamino)triphenylamine (NATA), 4,4',4"-tris(N-(naphthyl-1-yl)-N-phenylamino)triphenylamine (1T-NATA), 4,4',4"-tris(N-(naphthyl-2-yl)-N-phenylamino)triphenylamine (2T-NATA), copper phthalocyanine (CuPc), tris(4-carbazole-9-ylphenyl)amine (TCTA), N,N'-diphenyl-N,N'-bis(1- Naphthyl)-1,1'-biphenyl-4,4”-diamine (NPB or NPD), 1,4,5,8,9,11-hexaazatriphenylenehexanitrile (dipyrazino[2,3-f:2'3'-h]quinoxaline-2,3,6,7,10,11-hexanitrile; HAT-CN), 1,3,5-tris[4-(diphenylamino)phenyl]benzene (TDAPB), poly(3,4-ethylenedioxythiophene)polystyrene sulfonate (PEDOT / PSS), and N-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluorene-2-amine, but not limited thereto.

[0075] HTL 260 may include at least one compound selected from the group consisting of: N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD), NPB (NPD), 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP), poly[N,N'-bis(4-tert-butyl)-N,N'-bis(phenyl)biphenyldiamine] (Poly-TPD), poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-di-diphenyl)-1,1'-biphenyl)-1,4'-diamine](Poly-TPD), poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-diphenyl)-1,1'-biphenyl)-1,4'-diphenyl](N,N' ... The following are examples of butylphenyl-diphenylamine (TFB), bis-[4-(N,N-di-p-tolyl-amino)phenyl]cyclohexane (TAPC), 3,5-bis(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, and N-(biphenyl-4-yl)-N-(4-(9-phenyl-9H-carbazole-3-yl)phenyl)biphenyl-4-amine, but not limited to these.

[0076] ETL 270 may include at least one of the following: oxadiazoles, triazoles, phenanthrolines, benzoxazoles, benzothiazoles, benzimidazoles, and triazines. For example, ETL270 may include at least one compound selected from the group consisting of: tri-(8-hydroxyquinoline)aluminum (Alq3), 2-biphenyl-4-yl-5-(4-tert-butylphenyl)-1,3,4-diazole (PBD), spiro-PBD, lithium quinoline (Liq), 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBi), bis(2-methyl-8-quinoline-N1,O8)-(1,1'-biphenyl-4-phenol)aluminum (BAlq), 4,7-diphenyl-1,10-phenanthroline (Bphen), 2,9-bis(naphthyl-2-yl)4,7-diphenyl-1,10-phenanthroline (NBphen), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BC) P), 3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4-(naphth-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-3-yl)1,3,5-triazine (TmPPPyTz), poly[9,9-bis(3'-(N,N-dimethyl)-N-ethylammonium)-propyl)-2,7-fluorene]-alt-2,7-(9,9-dioctylfluorene)] (PFNBr), tris(phenylquinoxaline) (TPQ), and diphenyl-4-triphenylsilyl-phenylphosphine oxide (TSPO1), but not limited thereto.

[0077] EIL 280 may include, but is not limited to, at least one of alkali metal halides such as LiF, CsF, NaF or BaF2 and organometallic compounds such as Liq, lithium benzoate or sodium stearate.

[0078] The EBL 265 is located between the HTL 260 and the EML 240 to prevent electrons from transferring from the EML 240 to the HTL. 260, EBL265 may include at least one compound selected from the group consisting of: TCTA, tris[4-(diethylamino)phenyl]amine, N-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazole-3-yl)phenyl)-9H-fluorene-2-amine, TAPC, MTDATA, 1,3-bis(carbazole-9-yl)phenyl (mCP), 3,3'-bis(N-carbazole)-1,1'-biphenyl (mCBP), CuPc, N,N'-bis[4-(bis(3-methylphenyl)amino)phenyl]-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (DNTPD), TDAPB, DCDPA, and 2,8-bis(9-phenyl-9H-carbazole-3-yl)dibenzo[b,d]thiophene, but not limited thereto.

[0079] HBL 275 is located between EML 240 and ETL 270 to prevent holes from transferring from EML 240 to ETL 270. HBL 275 may include the aforementioned material of ETL 270. For example, the material of HBL 275 has a lower HOMO energy level than the material of EML 240 and may be at least one compound selected from the group consisting of: BCP, BAlq, Alq3, PBD, spiro-PBD, Liq, bis-4,5-(3,5-di-3-pyridylphenyl)-2-methylpyrimidine (B3PYMPM), bis[2-(diphenylphosphino)phenyl] ether oxide (DPEPO), 9-(6-(9H-carbazole-9-yl)pyridin-3-yl)-9H-3,9'-biscarbazole, and TSPO1, but is not limited thereto.

[0080] EML 240 includes a first compound as a delayed fluorescence material (or delayed fluorescence compound) and a second compound as a fluorescent material (or fluorescent compound). EML 240 includes a first compound and a second compound that provide green light emission, and OLED D1 is located in the green pixel region.

[0081] The first compound is represented by formula 1-1.

[0082] [Equation 1-1]

[0083]

[0084] In Formula 1-1, X1 is one of a single bond (or direct bond), C(R6)2, NR7, O, and S. Y is selected from the group consisting of: cyano (-CN), nitro (-NO2), halogen, C1 to C20 alkyl substituted with at least one of cyano, nitro, and halogen, C6 to C30 aryl substituted with at least one of cyano, nitro, and halogen, and C3 to C40 heteroaryl substituted with at least one of cyano, nitro, and halogen. R1 to R7 are each independently selected from the group consisting of: deuterium, tritium, substituted or unsubstituted C1 to C20 alkyl, substituted or unsubstituted C6 to C30 aryl, and substituted or unsubstituted C3 to C40 heteroaryl, or adjacent R1 to R7 are linked (combined, joined, or linked) to form an aromatic ring or heteroaromatic ring. L is a C6 to C30 aryl group. a1 and a2 are each independent integers from 0 to 5, a3 is an integer from 0 to 3, a4 and a5 are each independent integers from 0 to 4, n1 is 1 or 2, and n2 is an integer from 1 to 5.

[0085] For example, a1 to a3 can be 0, and n1 and n2 can be 1.

[0086] In this disclosure, C6 to C30 aryl (or C6 to C30 aryl) groups may be selected from the group consisting of: phenyl, biphenyl, terphenyl, naphthyl, anthracene, pentanenyl, indenyl, indenoindenyl, heptalenyl, biphenylenyl, indacenyl, phenanthrenyl, benzophenanthrenyl, dibenzophenanthrenyl, azulenyl, pyrenyl, fluoranthenyl, and triphenylenyl. Chrysenyl, tetraphenyl, tetrasenyl, picenyl, pentaphenyl, pentaphenyl, fluorenyl, indenofluorenyl, and spirofluorenyl.

[0087] In this disclosure, the C3 to C40 heteroaryl groups may be selected from the group consisting of: pyrroloyl, pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, tetraazinyl, imidazolyl, pyrazolyl, indoleyl, isoindoleyl, indazoleyl, indoleazinyl, pyrroloazinyl, carbazolyl, benzo[carbazolyl], dibenzo[carbazolyl], indole[carbazolyl], indo[carbazolyl], benzo[furano[carbazolyl], benzo[thiophene[carbazolyl], quinolinyl, isoquinolinyl, phthalazinyl, quinoxalinyl, cinolinyl, quinazolinyl, quinazinyl, quinolinyl, purine, phthalazinyl, quinoxalinyl, benzo[quinolinyl], benzo[isoquinolinyl], benzo[quinazolinyl], benzo[quinoxalinyl], acridineyl, phenazinyl , phenoxazinyl, phenthiazinyl, phenanthrolinel, pteridinyl, phenanthidyl, pteridinyl, cinnolinyl, naphridinyl, furanyl, oxazinyl, oxazolyl, oxadiazolyl, triazolyl, dioxinyl, benzofuranyl, dibenzofuranyl, thiopyranyl, xanthonyl, chromenyl, isochromenyl, thioazinyl, thioazinyl, thiophene, benzothiophene, dibenzothiophene, difuranopyrazinyl, benzofuranopyranopyranyl, benzothiophene, benzothiophene, benzothiophene, benzothiophene, benzothiophene, and benzothiophene, dibenzofuranyl.

[0088] In this disclosure, when alkyl, aryl and / or heteroaryl groups are substituted, the substituents may be selected from the group consisting of deuterium, tritium, cyano, halogen and C1 to C20 alkyl groups.

[0089] For example, in formula 1-1, L can be a phenylene group, and n1 can be 1. That is, formula 1-1 can be represented by formula 1-2.

[0090] [Equation 1-2]

[0091]

[0092] In Equation 1-2, X1 can be a single bond, two adjacent R5 bonds can be connected to form a heteroaromatic ring, and n2 can be 1. That is, Equation 1-2 can be represented by Equation 1-3.

[0093] [Equation 1-3]

[0094]

[0095] In formulas 1-3, X2 is one of NR8, O, and S, and R8 is selected from the group consisting of: hydrogen, deuterium, tritium, substituted or unsubstituted C1 to C20 alkyl, substituted or unsubstituted C6 to C30 aryl and substituted or unsubstituted C3 to C40 heteroaryl.

[0096] The first compound represented by one of formulas 1-1 to 1-3 may be one of the compounds in formula 1-4.

[0097] [Equations 1-4]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107]

[0108]

[0109]

[0110]

[0111]

[0112]

[0113]

[0114]

[0115]

[0116] The second compound is represented by formula 2-1.

[0117] [Equation 2-1]

[0118]

[0119] In Formula 2-1, R11 to R14 are each independently selected from the group consisting of: deuterium, tritium, substituted or unsubstituted C1 to C20 alkyl, substituted or unsubstituted C6 to C30 aryl, and substituted or unsubstituted C3 to C40, or two adjacent R11 to R14 are linked to form an aromatic ring or heteroaromatic ring. R21 to R28, R31 to R38 and R41 to R48 are each independently selected from the group consisting of: hydrogen, deuterium, tritium, substituted or unsubstituted C1 to C20 alkyl, substituted or unsubstituted C6 to C30 aryl, and substituted or unsubstituted C3 to C40 heteroaromatic. R29, R30, R39, R40, R49, and R50 are each independently selected from the group consisting of: hydrogen, deuterium, tritium, substituted or unsubstituted C1 to C20 alkyl, substituted or unsubstituted C6 to C30 aryl, and substituted or unsubstituted C3 to C40 heteroaryl, or at least one pair of R29 and R30, R39 and R40, and R49 and R50 connected together to form a ring. m1 to m3 are each independently 0 or 1, and at least one of m1 to m3 is 1. Furthermore, b1 and b4 are each independently integers from 0 to 4, and b2 and b3 are each independently integers from 0 to 3.

[0120] R11 to R14 can each be independently selected from the group consisting of substituted or unsubstituted C1 to C20 alkyl groups and substituted or unsubstituted C6 to C30 aryl groups, and b1 to b4 can be 0 or 1. For example, R11 to R14 can each be independently selected from the group consisting of methyl, tert-butyl, and phenyl groups.

[0121] R21 to R28, R31 to R38, and R41 to R48 can each be independently selected from the group consisting of hydrogen, substituted or unsubstituted C1 to C20 alkyl groups, and substituted or unsubstituted C6 to C30 aryl groups. For example, R21 to R28, R31 to R38, and R41 to R48 can each be independently selected from the group consisting of hydrogen, methyl, tert-butyl, and phenyl. More specifically, one of R21 to R28 can be selected from the group consisting of methyl, tert-butyl, and phenyl, while the remaining R21 to R28 can be hydrogen. One of R31 to R38 can be selected from the group consisting of methyl, tert-butyl, and phenyl, while the remaining R31 to R38 can be hydrogen. One of R41 to R48 can be selected from the group consisting of methyl, tert-butyl, and phenyl, while the remaining R41 to R48 can be hydrogen.

[0122] For example, the second compound of formula 2-1 can be one of the compounds in formula 2-2.

[0123] [Equation 2-2]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129]

[0130]

[0131] In EML 240, the weight percentage of the first compound can be greater than the weight percentage of the second compound.

[0132] In EML 240, the energy of the first compound is transferred to the second compound, and the second compound provides the emission.

[0133] The triplet exciton of the first compound in Formula 1-1 is converted into a singlet exciton through reverse systematic crossover (RISC), giving the first compound high quantum efficiency. However, because the first compound, as a delayed fluorescence material, has a wide full width at half maximum (FWHM), the color purity of the OLED decreases when the first compound is included in the EML as a dopant (or emitter).

[0134] On the other hand, the second compound of Formula 2-1 emits light with a narrow FWHM green wavelength range. Therefore, OLED D1 including the second compound can provide green emission with excellent color purity. However, since only the singlet excitons of the second compound participate in emission, OLED D including the second compound has low luminous efficiency (or quantum efficiency).

[0135] In the OLED D1 of this disclosure, the OLED D1 provides superfluorescence because the EML 240 includes a first compound with high quantum efficiency and a second compound with narrow FWHM.

[0136] That is, the triplet exciton of the first compound is converted into a singlet exciton of the first compound, and the singlet exciton of the first compound is converted into a singlet exciton of the second compound. Then, the second compound provides light emission, enabling the OLED D1 to have a narrow field of view (FWHM) and high luminous efficiency.

[0137] To improve the energy transfer efficiency from the first compound to the second compound, the emission spectrum of the first compound and the absorption spectrum of the second compound can have an overlap of about 35% or more.

[0138] EML 240 may further include a third compound represented by Formula 3-1.

[0139] [Equation 3-1]

[0140]

[0141] In Formula 3-1, R51 and R52 are each independently selected from the group consisting of: deuterium, tritium, substituted or unsubstituted C1 to C20 alkyl groups, substituted or unsubstituted C6 to C30 aryl groups, and substituted or unsubstituted C3 to C40 heteroaryl groups, or two adjacent R51 and R52 are connected to each other to form an aromatic ring or a heteroaromatic ring. Ar1 and Ar2 are each independently selected from Formulas 3-2 to 3-4, and c1 and c2 are each independently integers from 0 to 4.

[0142] [Equation 3-2]

[0143]

[0144] [Equation 3-3]

[0145]

[0146] [Equation 3-4]

[0147]

[0148] Ar1 and Ar2 can be the same or different.

[0149] Adjacent R51 and R52 can be connected to form a heteroaromatic ring. In this case, Equation 3-1 can be represented by Equation 3-5.

[0150] [Equation 3-5]

[0151]

[0152] In formulas 3-5, X3 is one of O, S and NR53, and R53 is selected from the group consisting of: hydrogen, deuterium, tritium, substituted or unsubstituted C1 to C20 alkyl, substituted or unsubstituted C6 to C30 aryl and substituted or unsubstituted C3 to C40 heteroaryl.

[0153] For example, the third compound can be one of the compounds in formulas 3-6.

[0154] [Equation 3-6]

[0155]

[0156]

[0157] In EML 240, the weight percentage of the third compound can be greater than the weight percentage of the second compound and can be equal to or less than the weight percentage of the first compound.

[0158] In EML 240, the third compound acts as the matrix, the second compound acts as the dopant (or luminescent material), and the first compound acts as the auxiliary matrix or auxiliary dopant.

[0159] Holes from the first electrode 210, which serves as the anode, and electrons from the second electrode 230, which serves as the cathode, combine in the matrix to generate excitons. These excitons are transferred to a first compound, where triplet excitons are converted to singlet excitons. The singlet excitons from the first compound are then transferred to a second compound, which provides the light emission.

[0160] In EML 240, the singlet energy level of the first compound is lower than the singlet energy level of the third compound serving as the matrix and higher than the singlet energy level of the second compound. Furthermore, the triplet energy level of the first compound is lower than the triplet energy level of the third compound serving as the matrix and higher than the triplet energy level of the second compound.

[0161] The energy difference between the lowest unoccupied molecular orbital (LUMO) level of the second compound as a fluorescent material (FD) and the LUMO level of the first compound as a delayed fluorescence material (TD) can be greater than approximately -0.6 eV and less than approximately 0.1 eV. (0.1 ≧ LUMO(FD) - LUMO(TD) ≧ -0.6)

[0162] The highest occupied molecular orbital (HOMO) energy level of the second compound as a fluorescent material (FD) can be equal to or higher than the highest occupied molecular orbital (HOMO) energy level of the first compound as a delayed fluorescent material (TD).

[0163] Furthermore, the difference between the triplet energy level and the singlet energy level of the first compound can be about 0.3 eV or less, and the band gap of the first compound can be about 2.0 eV to about 3.0 eV.

[0164] As described above, the first compound exhibiting delayed fluorescence properties has high quantum efficiency and poor color purity due to its wide FWHM. On the other hand, the second compound exhibiting fluorescence properties has a narrow FWHM and low luminescence efficiency.

[0165] However, in the OLED D1 of this disclosure, the singlet excitons of the first compound, which serves as a delayed fluorescence material, are transferred to the second compound, which serves as a fluorescent material, and the second compound provides the emission. Therefore, the luminous efficiency and color purity of the OLED D1 are improved. Furthermore, the luminous efficiency of the OLED D1 is further improved because of the large overlap between the emission spectrum of the first compound represented by Formula 1-1 and the absorption spectrum of the second compound represented by Formula 2-1.

[0166] [OLED]

[0167] An OLED is formed by sequentially depositing an anode (ITO, 70 nm), a HIL (Equation 4-1, 10 nm), an HTL (Equation 4-2, 140 nm), an EBL (Equation 4-3, 10 nm), an EML (40 nm), an HBL (Equation 4-4, 10 nm), an ETL (Equation 4-5, 30 nm), an EIL (Liq, 1 nm), and a cathode (Mg:Ag, 10 nm).

[0168] [Equation 4-1]

[0169]

[0170] [Equation 4-2]

[0171]

[0172] [Equation 4-3]

[0173]

[0174] [Equation 4-4]

[0175]

[0176] [Equation 4-5]

[0177]

[0178] 1. Comparative Example

[0179] (1) Comparative Example 1 (Ref 1)

[0180] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 5-1 (50 wt%) from Formula 5, and compound 2-3 (1 wt%) from Formula 2-2.

[0181] (2) Comparative Example 2 (Ref 2)

[0182] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 5-2 (50 wt%) from Formula 5, and compound 2-3 (1 wt%) from Formula 2-2.

[0183] (3) Comparative Example 3 (Ref 3)

[0184] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 5-3 (50 wt%) from Formula 5, and compound 2-3 (1 wt%) from Formula 2-2.

[0185] (4) Comparative Example 4 (Ref 4)

[0186] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 5-4 (50 wt%) from Formula 5, and compound 2-3 (1 wt%) from Formula 2-2.

[0187] (5) Comparative Example 5 (Ref 5)

[0188] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 5-1 (50 wt%) from Formula 5, and compound 2-5 (1 wt%) from Formula 2-2.

[0189] (6) Comparative Example 6 (Ref 6)

[0190] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 5-2 (50 wt%) from Formula 5, and compound 2-5 (1 wt%) from Formula 2-2.

[0191] (7) Comparative Example 7 (Ref 7)

[0192] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 5-3 (50 wt%) from Formula 5, and compound 2-5 (1 wt%) from Formula 2-2.

[0193] (8) Comparative Example 8 (Ref 8)

[0194] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 5-4 (50 wt%) from Formula 5, and compound 2-5 (1 wt%) from Formula 2-2.

[0195] (9) Comparative Example 9 (Ref 9)

[0196] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 5-1 (50 wt%) from Formula 5, and compound 2-41 (1 wt%) from Formula 2-2.

[0197] (10) Comparative Example 10 (Ref 10)

[0198] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 5-2 (50 wt%) from Formula 5, and compound 2-41 (1 wt%) from Formula 2-2.

[0199] (11) Comparative Example 11 (Ref 11)

[0200] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 5-3 (50 wt%) from Formula 5, and compound 2-41 (1 wt%) from Formula 2-2.

[0201] (12) Comparative Example 12 (Ref 12)

[0202] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 5-4 (50 wt%) from Formula 5, and compound 2-41 (1 wt%) from Formula 2-2.

[0203] 2. Example

[0204] (1) Example 1 (Ex1)

[0205] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 1-3 (50 wt%) from Formula 1-4, and compound 2-3 (1 wt%) from Formula 2-2.

[0206] (2) Example 2 (Ex2)

[0207] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 1-14 (50 wt%) from Formula 1-4, and compound 2-3 (1 wt%) from Formula 2-2.

[0208] (3) Example 3 (Ex3)

[0209] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 1-15 (50 wt%) from Formula 1-4, and compound 2-3 (1 wt%) from Formula 2-2.

[0210] (4) Example 4 (Ex4)

[0211] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 1-16 (50 wt%) from Formula 1-4, and compound 2-3 (1 wt%) from Formula 2-2.

[0212] (5) Example 5 (Ex5)

[0213] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 1-3 (50 wt%) from Formula 1-4, and compound 2-5 (1 wt%) from Formula 2-2.

[0214] (6) Example 6 (Ex6)

[0215] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 1-14 (50 wt%) from Formula 1-4, and compound 2-5 (1 wt%) from Formula 2-2.

[0216] (7) Example 7 (Ex7)

[0217] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 1-15 (50 wt%) from Formula 1-4, and compound 2-5 (1 wt%) from Formula 2-2.

[0218] (8) Example 8 (Ex8)

[0219] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 1-16 (50 wt%) from Formula 1-4, and compound 2-5 (1 wt%) from Formula 2-2.

[0220] (9) Example 9 (Ex9)

[0221] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 1-3 (50 wt%) from Formula 1-4, and compound 2-41 (1 wt%) from Formula 2-2.

[0222] (10) Example 10 (Ex10)

[0223] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 1-14 (50 wt%) from Formula 1-4, and compound 2-41 (1 wt%) from Formula 2-2.

[0224] (11) Example 11 (Ex11)

[0225] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 1-15 (50 wt%) from Formula 1-4, and compound 2-41 (1 wt%) from Formula 2-2.

[0226] (12) Example 12 (Ex12)

[0227] EML was formed using compound 3-1 (49 wt%) from Formula 3-6, compound 1-16 (50 wt%) from Formula 1-4, and compound 2-41 (1 wt%) from Formula 2-2.

[0228] [Formula 5]

[0229]

[0230] The luminescence characteristics of the OLEDs in Comparative Examples 1 to 12 and Examples 1 to 12 were measured, namely, driving voltage (V), current efficiency (cd / A), and maximum emission wavelength of the delayed fluorescent material (TD). EL ), the maximum absorption wavelength of fluorescent materials (FD) abs The overlap between the maximum emission wavelength range of the delayed fluorescent material and the maximum absorption wavelength range of the fluorescent material is listed in Tables 1 to 3.

[0231] Table 1

[0232]

[0233] Table 2

[0234]

[0235] Table 3

[0236]

[0237] As shown in Tables 1 to 3, compared with the OLEDs of Comparative Examples 1 to 12, the OLEDs of Examples 1 to 12 include a first compound represented by Formula 1-1 and a second compound represented by Formula 2-1, and their luminous efficiency is significantly increased.

[0238] In other words, compared with OLEDs that include delayed fluorescent materials, namely compounds 5-1 to 5-4 (where the cyano group is directly connected to the phenylene linkage), OLEDs that include delayed fluorescent materials, namely compounds 1-3 and 1-14 to 1-16 (where the cyano group is indirectly connected to the phenylene linkage via the aryl group), and also include fluorescent materials represented by Formula 2-1, have significantly increased luminous efficiency.

[0239] Reference Figure 4 This is a schematic diagram illustrating the relationship between the emission spectrum of the delayed fluorescent material and the absorption spectrum of the fluorescent material in an OLED. The emission spectrum of the delayed fluorescent material, namely compound 5-1 "TD" in formula 5, has an overlap of about 30% with the absorption spectrum of the fluorescent material, namely compound 2-3 "FD" in formula 2-2.

[0240] On the other hand, refer to Figure 5 This is a schematic diagram illustrating the relationship between the emission spectrum of the first compound and the absorption spectrum of the second compound in the OLED according to the second embodiment of the present disclosure. The emission spectrum of the first compound, namely compound 1-15 "TD" in formula 1-4, has an overlap of about 37% with the absorption spectrum of the fluorescent material, namely compound 2-3 "FD" in formula 2-2.

[0241] That is, in the first compound of this disclosure, since the substituent Y (selected from the group consisting of cyano (-CN), nitro (-NO2), halogen, C1 to C20 alkyl groups substituted with at least one of cyano, nitro, and halogen, C6 to C30 aryl groups substituted with at least one of cyano, nitro, and halogen, and C3 to C40 heteroaryl groups substituted with at least one of cyano, nitro, and halogen) is attached to the phenylene linkage group through the aryl moiety (i.e., L in Formula 1-1), the emission spectrum of the first compound shifts to a shorter wavelength range, and the overlap between the emission spectrum of the first compound and the absorption spectrum of the second compound increases. As a result, the luminous efficiency of the OLED D1 including the first compound and the second compound is significantly increased.

[0242] Figure 6 This is a schematic cross-sectional view of an OLED according to a third embodiment of the present disclosure.

[0243] like Figure 6 As shown, the OLED D2 according to the third embodiment of this disclosure includes a first electrode 310 and a second electrode 330 facing each other, and a light-emitting layer 320 between them. The light-emitting layer 320 includes an EML 340. Figure 2 The organic light-emitting display device 100 may include a red pixel area, a green pixel area and a blue pixel area, and the OLED D2 may be located in the green pixel area.

[0244] The first electrode 310 can be an anode, and the second electrode 330 can be a cathode. One of the first electrode 310 and the second electrode 330 can be a transparent electrode (or a semi-transparent electrode), and the other of the first electrode 310 and the second electrode 330 can be a reflective electrode.

[0245] The light-emitting layer 320 may further include at least one of an HTL 360 between the first electrode 310 and the EML 340 and an ETL 370 between the second electrode 330 and the EML 340.

[0246] Furthermore, the light-emitting layer 320 may further include at least one of HIL 350 between the first electrode 310 and HTL 360 and EIL 380 between the second electrode 330 and ETL 370.

[0247] Furthermore, the light-emitting layer 320 may further include at least one of EBL 365 between HTL 360 and EML 340 and HBL 375 between EML 340 and ETL 370.

[0248] EML 340 includes a first EML (first layer or lower light-emitting material layer) 342 and a second EML (second layer or upper light-emitting material layer) 344 sequentially stacked on the first electrode 310. That is, the second EML 344 is located between the first EML 342 and the second electrode 330.

[0249] In EML 340, one of the first EML 342 and the second EML 344 includes the second compound of Formula 2-1 as a fluorescent material, and the other of the first EML 342 and the second EML 344 includes the first compound of Formula 1-1 as a delayed fluorescent material. Furthermore, the first EML 342 and the second EML 344 may further include a fourth compound and a fifth compound as a matrix, respectively. The fourth compound in the first EML 342 and the fifth compound in the second EML 344 may be the same or different. For example, the fourth compound and the fifth compound may each be the same as the third compound.

[0250] The explanation will cover the OLED containing the first compound in the second EML 344.

[0251] As mentioned above, the first compound exhibiting delayed fluorescence properties has high quantum efficiency. However, due to the wide free wave size (FWHM) of the first compound, the fifth compound suffers from a disadvantage in terms of color purity. On the other hand, the second compound exhibiting fluorescence properties has a narrow FWHM. However, since the triplet excitons of the second compound do not participate in luminescence, the second compound suffers from a disadvantage in terms of luminescence efficiency.

[0252] In OLED D2, the second compound provides luminescence because the triplet exciton energy of the first compound in the second EML 344 is converted to the singlet exciton energy of the first compound via RISC, and the singlet exciton energy of the first compound is transferred to the singlet exciton energy of the second compound in the first EML 342. Therefore, both the singlet and triplet exciton energies participate in luminescence, thereby improving luminescence efficiency. Furthermore, since luminescence is provided by the second compound as a fluorescent material, luminescence with a narrow FWHM is provided.

[0253] The absorption spectrum of the second compound and the emission spectrum of the first compound have an overlap of approximately 35% or greater. Therefore, the energy of the first compound in the second EML 344 is effectively transferred to the second compound in the first EML 342, thereby improving the luminous efficiency of OLED D2.

[0254] In the first EML 342, the weight percentage of the fourth compound can be greater than that of the second compound. In the second EML 344, the weight percentage of the fifth compound can be equal to or greater than that of the first compound. The weight percentage of the second compound in the first EML 342 can be less than that of the first compound in the second EML 344. As a result, sufficient energy transfer is achieved from the first compound in the second EML 344 to the second compound in the first EML 342 via FRET, which can further improve the luminous efficiency of the OLED D2. For example, the second compound in the first EML 342 can have a weight percentage from 0.01 wt% to 10 wt%, preferably from 0.01 wt% to 5 wt%, and the first compound in the second EML 344 can have a weight percentage from 30 wt% to 50 wt%, preferably from 40 wt% to 50 wt%, but is not limited thereto.

[0255] The matrix of the first EML 342 can be the same as that of the EBL 365. In this case, the first EML 342 can have both electron blocking and luminescent functions. That is, the first EML 342 can be used as a buffer layer that blocks electrons. When the EBL 365 is omitted, the first EML 342 can be used as both a luminescent material layer and an electron blocking layer.

[0256] When the second EML 344 comprises the second compound and the first EML 342 comprises the first compound, the matrix of the second EML 344 can be the same as the material of the HBL 375. In this case, the second EML 344 can have both hole-blocking and light-emitting functions. That is, the second EML 344 can be used as a buffer layer to block holes. When the HBL 375 is omitted, the second EML 344 can be used as both a light-emitting material layer and a hole-blocking layer.

[0257] Figure 7 This is a schematic cross-sectional view of an OLED according to the fourth embodiment of the present disclosure.

[0258] like Figure 7 As shown, the OLED D3 according to the fourth embodiment of this disclosure includes a first electrode 410 and a second electrode 430 facing each other, and a light-emitting layer 420 between them. The light-emitting layer 420 includes an EML 440. Figure 2 The organic light-emitting display device 100 may include a red pixel area, a green pixel area and a blue pixel area, and the OLED D3 may be located in the green pixel area.

[0259] The first electrode 410 can be an anode, and the second electrode 430 can be a cathode. One of the first electrode 410 and the second electrode 430 can be a transparent electrode (or a semi-transparent electrode), and the other of the first electrode 410 and the second electrode 430 can be a reflective electrode.

[0260] The light-emitting layer 420 may further include at least one of HTL 460 between the first electrode 410 and EML 440 and ETL 470 between the second electrode 430 and EML 440.

[0261] Furthermore, the light-emitting layer 420 may further include at least one of HIL 450 between the first electrode 410 and HTL 460 and EIL 480 between the second electrode 430 and ETL 470.

[0262] Furthermore, the light-emitting layer 420 may further include at least one of EBL 465 between HTL 460 and EML 440 and HBL 475 between EML 440 and ETL 470.

[0263] EML 440 includes a first EML (first layer, intermediate light-emitting material layer) 442, a second EML (second layer, lower light-emitting material layer) 444 between the first EML 442 and the first electrode 410, and a third EML (third layer, upper light-emitting material layer) 446 between the first EML 442 and the second electrode 430. That is, EML 440 has a three-layer structure consisting of the second EML 444, the first EML 442, and the third EML 446 stacked sequentially.

[0264] For example, the first EML 442 can be located between EBL 465 and HBL 475, the second EML 444 can be located between EBL 465 and the first EML 442, and the third EML 446 can be located between HBL 475 and the first EML 442.

[0265] In EML 440, the first EML 442 comprises a first compound of Formula 1-1 as a delayed fluorescence material, and the second EML 444 and the third EML 446 each comprise a second compound of Formula 2-1 as a fluorescent compound. The second compound in the second EML 444 and the second compound in the third EML 446 may be the same or different. The first EML 442, the second EML 444, and the third EML 446 may further comprise a sixth compound, a seventh compound, and an eighth compound as a matrix, respectively. The sixth compound in the first EML 442, the seventh compound in the second EML 444, and the eighth compound in the third EML 446 may be the same or different. For example, the sixth compound, the seventh compound, and the eighth compound may each be the same as the third compound.

[0266] In OLED D3, the triplet exciton energy of the fifth compound in the first EML 442 is converted to the singlet exciton energy of the third compound via RISC, and the singlet exciton energy of the third compound is transferred to the singlet exciton energy of the second compound in the second EML 444 and third EML 446. Therefore, the second compounds in the second EML 444 and third EML 446 provide luminescence. Thus, both singlet and triplet exciton energies participate in luminescence, thereby improving luminescence efficiency. Furthermore, since luminescence is provided by the second compound as a fluorescent material, luminescence with fluorescence intensity (FWHM) is provided.

[0267] As described above, the absorption spectrum of the second compound and the emission spectrum of the first compound have an overlap of about 35% or more.

[0268] Therefore, the energy of the fifth compound in the first EML 442 is effectively transferred to the second compound in the second EML 444 and the third EML 446, thereby improving the luminous efficiency of OLED D3.

[0269] In the first EML 442, the weight percentage of the sixth compound may be equal to or greater than the weight percentage of the first compound. In the second EML 444, the weight percentage of the seventh compound may be greater than the weight percentage of the second compound. In the third EML 446, the weight percentage of the eighth compound may be greater than the weight percentage of the second compound.

[0270] Furthermore, the weight percentage of the first compound in the first EML 442 can be greater than the weight percentage of each of the second compounds in the second EML 444 and the third EML 446. As a result, sufficient energy transfer is achieved from the fifth compound in the first EML 442 to the second compounds in the second EML 444 and the third EML 446 via FRET, and the luminous efficiency of the OLED D3 can be further improved. For example, the first compound in the first EML 442 can have a weight percentage of 30% to 50% by weight, preferably 40% to 50% by weight, and the second compounds in each of the second EML 444 and the third EML 446 can have a weight percentage of 0.01% to 10% by weight, preferably 0.01% to 5% by weight, but are not limited thereto.

[0271] The matrix of the second EML 444 can be the same as that of the EBL 465. In this case, the second EML 444 can have both electron blocking and luminescent functions. That is, the second EML 444 can be used as a buffer layer to block electrons. When the EBL 465 is omitted, the second EML 444 can be used as both a luminescent material layer and an electron blocking layer.

[0272] The matrix of the third EML 446 can be the same as that of the HBL 475. In this case, the third EML 446 can have both hole-blocking and light-emitting functions. That is, the third EML 446 can be used as a buffer layer to block holes. When the HBL475 is omitted, the third EML 446 can be used as both a light-emitting material layer and a hole-blocking layer.

[0273] The matrix in the second EML 444 can be the same material as that in EBL 465, and the matrix in the third EML 446 can be the same material as that in HBL 475. In this case, the second EML 444 can have both electron blocking and light-emitting functions, and the third EML 446 can have both hole blocking and light-emitting functions. That is, the second EML 444 can be used as a buffer layer to block electrons, and the third EML 446 can be used as a buffer layer to block holes. When EBL 465 and HBL 475 are omitted, the second EML 444 can be used as both a light-emitting material layer and an electron blocking layer, while the third EML 446 can be used as both a light-emitting material layer and a hole blocking layer.

[0274] Figure 8 This is a schematic cross-sectional view of an OLED according to the fifth embodiment of the present disclosure.

[0275] like Figure 8 As shown, OLED D4 includes a first electrode 510 and a second electrode 530 facing each other, and a light-emitting layer 520 between them. The light-emitting layer 520 includes an EML 440. Figure 2 The organic light-emitting display device 100 may include a red pixel area, a green pixel area and a blue pixel area, and the OLED D4 may be located in the green pixel area.

[0276] The first electrode 510 can be an anode, and the second electrode 530 can be a cathode. One of the first electrode 510 and the second electrode 530 can be a transparent electrode (or a semi-transparent electrode), and the other of the first electrode 510 and the second electrode 530 can be a reflective electrode.

[0277] The light-emitting layer 520 includes a first light-emitting portion 540 containing a first EML 550 and a second light-emitting portion 560 containing a second EML 570. Furthermore, the light-emitting layer 520 may further include a charge generation layer (CGL) 580 between the first light-emitting portion 540 and the second light-emitting portion 560.

[0278] CGL 580 is located between the first light-emitting part 540 and the second light-emitting part 560, such that the first light-emitting part 540, CGL 580 and the second light-emitting part 560 are sequentially stacked on the first electrode 510. That is, the first light-emitting part 540 is located between the first electrode 510 and CGL 580, and the second light-emitting part 560 is located between the second electrode 530 and CGL 580.

[0279] The first light-emitting part 540 includes a first EML 550.

[0280] Furthermore, the first light-emitting portion 540 may further include at least one of the following: a first HTL 540b between the first electrode 510 and the first EML 550, a HIL 540a between the first electrode 510 and the first HTL 540b, and an ETL 540e between the first EML 550 and the CGL 580.

[0281] Furthermore, the first light-emitting portion 540 may further include at least one of a first EBL 540c between the first HTL 540b and the first EML 550 and a first HBL 540d between the first EML 550 and the first ETL 540e.

[0282] The second light-emitting part 560 includes a second EML 570.

[0283] Furthermore, the second light-emitting portion 560 may further include at least one of the following: a second HTL 560a between the CGL 580 and the second EML 570; a second ETL 560d between the second EML 570 and the second electrode 164; and an EIL 560e between the second ETL 560d and the second electrode 530.

[0284] Furthermore, the second light-emitting portion 560 may further include at least one of the second EBL 560b between the second HTL 560a and the second EML 570 and the second HBL 560c between the second EML 570 and the second ETL 560d.

[0285] CGL 580 is located between the first light-emitting part 540 and the second light-emitting part 560. That is, the first light-emitting part 540 and the second light-emitting part 560 are connected to each other through CGL 580. CGL 580 can be a PN junction type CGL composed of N-type CGL 582 and P-type CGL 584.

[0286] The N-type CGL 582 is located between the first ETL 540e and the second HTL 560a, and the P-type CGL 584 is located between the N-type CGL 582 and the second HTL 560a. The N-type CGL 582 provides electrons to the first EML 550 of the first light-emitting part 540, and the P-type CGL 584 provides holes to the second EML 570 of the second light-emitting part 560.

[0287] The first EML 550 and the second EML 570 are green EMLs. At least one of the first EML 550 and the second EML 570 comprises a first compound represented by Formula 1-1 and a second compound represented by Formula 2-1.

[0288] For example, the first EML 550 may include a first compound represented by Formula 1-1 as a delayed fluorescence material and a second compound represented by Formula 2-1 as a fluorescent material. The first EML 550 may further include a third compound as a matrix. The third compound may be a compound represented by Formula 3-1.

[0289] In the first EML 550, the weight percentage of the first compound can be greater than that of the second compound, and can be equal to or greater than that of the third compound. When the weight percentage of the first compound is greater than that of the second compound, an energy transfer from the first compound to the second compound is effectively generated. For example, in the first EML 550, the second compound can have a weight percentage of 0.01% to 10% by weight, preferably 0.01% to 5% by weight, more preferably 0.1% to 5% by weight, and the first compound can have a weight percentage of 30% to 60% by weight, preferably 40% to 60% by weight, more preferably 40% to 50% by weight, or 45% to 55% by weight, but is not limited thereto.

[0290] The second EML 570 may include a first compound represented by Formula 1-1 and a second compound represented by Formula 2-1. Alternatively, the second EML 570 may include a delayed fluorescence compound and / or a fluorescent compound, wherein at least one of the compounds is different from the first and second compounds in the first EML 550, such that the first EML 550 and the second EML 570 have different emission wavelengths or luminous efficiencies. Alternatively, the second EML 570 may include a matrix and a green dopant as a phosphorescent material.

[0291] In the OLED D4 disclosed herein, the singlet state energy level of the first compound, which serves as a delayed fluorescence material, is transferred to the second compound, which serves as a fluorescent material, and light emission is generated from the second compound. Therefore, the luminous efficiency and color purity of the OLED D4 are improved. Furthermore, since the first compound of formula 1-1 and the second compound of formula 2-1 are included in the first EML 550, the luminous efficiency and color purity of the OLED D4 are further improved. Moreover, since the OLED D4 has a double-layered structure with two green EMLs (double-layered structure), the color sensitivity of the OLED D4 is improved and / or the luminous efficiency of the OLED D4 is optimized.

[0292] Figure 9 This is a schematic cross-sectional view of an organic light-emitting display device according to the sixth embodiment of this disclosure.

[0293] like Figure 9 As shown, the organic light-emitting display device 1000 includes a substrate 1010 defining first to third pixel regions P1, P2, and P3, a TFT Tr above the substrate 1010, and an OLED D5. The OLED D5 is disposed above and connected to the TFT Tr. For example, the first to third pixel regions P1, P2, and P3 can be a green pixel region, a red pixel region, and a blue pixel region, respectively.

[0294] The substrate 1010 can be a glass substrate or a flexible substrate. For example, the flexible substrate can be a polyimide (PI) substrate, a polyethersulfone (PES) substrate, a polyethylene naphthalate (PEN) substrate, a polyethylene terephthalate (PET) substrate, or a polycarbonate (PC) substrate.

[0295] A buffer layer 1012 is formed on a substrate 1010, and a TFT Tr is formed on the buffer layer 1012. The buffer layer 1012 can be omitted.

[0296] For example Figure 2 As explained, a TFT Tr can include a semiconductor layer, a gate, a source, and a drain, and can be used as a driving element.

[0297] A planarization layer (or passivation layer) 1050 is formed on the TFT Tr. The planarization layer 1050 has a flat top surface and includes a drain contact hole 1052 that exposes the drain of the TFT Tr.

[0298] OLED D5 is disposed on planarization layer 1050 and includes a first electrode 1060, an emissive layer 1062, and a second electrode 1064. The first electrode 1060 is connected to the drain of TFT Tr, and the emissive layer 1062 and the second electrode 1064 are sequentially stacked on the first electrode 1060. OLED D5 is disposed in each of the first pixel regions P1 to the third pixel regions P3, and emits different colors of light in each of the three pixel regions. For example, OLED D5 in the first pixel region P1 can emit green light, OLED D5 in the second pixel region P2 can emit red light, and OLED D5 in the third pixel region P3 can emit blue light.

[0299] The first electrode 1060 is formed separately in the first pixel region P1 to the third pixel region P3, and the second electrode 1064 is formed integrally to cover the first pixel region P1 to the third pixel region P3.

[0300] The first electrode 1060 is one of the anode and the cathode, and the second electrode 1064 is the other of the anode and the cathode. In addition, one of the first electrode 1060 and the second electrode 1064 can be a light-transmitting electrode (or a semi-transparent electrode), and the other of the first electrode 1060 and the second electrode 1064 can be a reflective electrode.

[0301] For example, the first electrode 1060 may be an anode and may include a transparent conductive oxide material layer formed of a transparent conductive oxide (TCO) material having a relatively high work function. The second electrode 1064 may be a cathode and may include a metallic material layer formed of a low-resistance metallic material having a relatively low work function. For example, the transparent conductive oxide material layer of the first electrode 1060 may include at least one of indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), tin oxide (SnO), zinc oxide (ZnO), indium copper oxide (ICO), or aluminum zinc oxide (Al:ZnO, AZO), and the second electrode 1064 may include Al, Mg, Ca, Ag, alloys thereof such as Mg-Ag alloys, or combinations thereof.

[0302] In the bottom-emitting organic light-emitting display device 1000, the first electrode 1060 may have a single-layer structure with a transparent conductive oxide material layer.

[0303] On the other hand, in the top-emitting organic light-emitting display device 1000, a reflective electrode or reflective layer can be formed below the first electrode 1060. For example, the reflective electrode or reflective layer can be formed of silver or aluminum palladium copper (APC) alloy. In this case, the first electrode 1060 can have a three-layer structure of ITO / Ag / ITO or ITO / APC / ITO. Furthermore, the second electrode 1064 can have a thin profile (small thickness) to provide light transmission characteristics (or semi-transparency characteristics).

[0304] A dam layer 1066 is formed on the planarization layer 1050 to cover the edge of the first electrode 1060. That is, the dam layer 1066 is located at the boundary between the first pixel region P1 and the third pixel region P3 and exposes the center of the first electrode 1060 in the first pixel region P1 to the third pixel region P3.

[0305] A light-emitting layer 1062, serving as a light-emitting unit, is formed on the first electrode 1060. The light-emitting layer 1062 may have a single-layer structure of EML. Alternatively, the light-emitting layer 1062 may further include at least one of HIL, HTL, EBL, sequentially stacked between the first electrode 1060 and the EML, and HBL, ETL, and EIL sequentially stacked between the EML and the second electrode 1064.

[0306] In the first pixel region P1, which is the green pixel region, the EML of the emissive layer 1062 includes a first compound as a delayed fluorescence material and a second compound as a fluorescent material. The EML of the emissive layer 1062 may further include a third compound as a matrix. The first compound is represented by Formula 1-1, the second compound by Formula 2-1, and the third compound by Formula 3-1.

[0307] An encapsulation film 1070 is formed on the second electrode 1064 to prevent moisture from penetrating into the OLED D5. The encapsulation film 1070 may have a three-layer structure including a first inorganic insulating layer, an organic insulating layer, and a second inorganic insulating layer, but is not limited thereto.

[0308] The organic light-emitting display device 1000 may further include a polarizing plate (not shown) for reducing ambient light reflection. For example, the polarizing plate may be a circular polarizing plate. In the bottom-emitting organic light-emitting display device 1000, the polarizing plate may be disposed below the substrate 1010. In the top-emitting organic light-emitting display device 1000, the polarizing plate may be disposed above or above the encapsulation film 1070.

[0309] Figure 10 This is a schematic cross-sectional view of an OLED according to the seventh embodiment of the present disclosure.

[0310] like Figure 10As shown, OLED D5 is located in each of the first pixel regions P1 to the third pixel regions P3, and includes a first electrode 1060 and a second electrode 1064 facing each other and an emissive layer 1062 between them. The emissive layer 1062 includes an EML 1090.

[0311] The first electrode 1060 can be an anode, and the second electrode 1064 can be a cathode. For example, the first electrode 1060 can be a reflective electrode, and the second electrode 1064 can be a light-transmitting electrode (or a semi-transparent electrode).

[0312] The light-emitting layer 1062 may further include an HTL 1082 between the first electrode 1060 and the EML 1090 and an ETL 1094 between the EML 1090 and the second electrode 1064.

[0313] Furthermore, the light-emitting layer 1062 may further include HIL 1080 between the first electrode 1060 and HTL 1082 and EIL 1096 between ETL 1094 and the second electrode 1064.

[0314] Furthermore, the light-emitting layer 1062 may further include an EBL 1086 between EML 1090 and HTL 1082 and an HBL 1092 between EML 1090 and ETL 1094.

[0315] Furthermore, the light-emitting layer 1062 may further include an auxiliary HTL 1084 between HTL 1082 and EBL 1086. The auxiliary HTL 1084 may include a first auxiliary HTL 1084a in the first pixel region P1, a second auxiliary HTL 1084b in the second pixel region P2, and a third auxiliary HTL 1084c in the third pixel region P3.

[0316] The first auxiliary HTL 1084a has a first thickness, the second auxiliary HTL 1084b has a second thickness, and the third auxiliary HTL 1084c has a third thickness. The first thickness is less than the second thickness and greater than the third thickness, enabling the OLED D5 to provide a microcavity structure.

[0317] That is, by using first to third auxiliary HTLs 1084a, 1084b, and 1084c with different thicknesses, the distance between the first electrode 1060 and the second electrode 1064 in the first pixel region P1 (where light in a first wavelength range, such as green light, is emitted) is smaller than the distance between the first electrode 1060 and the second electrode 1064 in the second pixel region P2 (where light in a second wavelength range greater than the first wavelength range, such as red light, is emitted), and larger than the distance between the first electrode 1060 and the second electrode 1064 in the third pixel region P3 (where light in a third wavelength range less than the first wavelength range, such as blue light, is emitted). Therefore, the luminous efficiency of the OLED D5 is improved.

[0318] exist Figure 10 In this configuration, the third auxiliary HTL 1084c is formed in the third pixel region P3. Alternatively, a microcavity structure can be provided without the third auxiliary HTL 1084c.

[0319] A capping layer (not shown) for improving light extraction characteristics can be further formed on the second electrode 1084.

[0320] EML 1090 includes a first EML 1090a in the first pixel region P1, a second EML 1090b in the second pixel region P2, and a third EML 1090c in the third pixel region P3. The first to third EMLs 1090a, 1090b, and 1090c can be green EML, red EML, and blue EML, respectively.

[0321] The first EML 1090a in the first pixel region P1 includes a first compound as a delayed fluorescence material and a second compound as a fluorescent material. The first EML 1090a in the first pixel region P1 may further include a third compound as a matrix. The first compound is represented by Formula 1-1, the second compound by Formula 2-1, and the third compound by Formula 3-1.

[0322] In the first EML 1090a in the first pixel region Pl, the weight % of the first compound can be greater than the weight % of the second compound, and can be equal to or greater than the weight % of the third compound. When the weight % of the first compound is greater than the weight % of the second compound, an energy transfer from the first compound to the second compound is effectively generated.

[0323] For example, in the first EML 1090a in the first pixel region Pl, the second compound may have 0.01 wt% to 10 wt%, preferably 0.01 wt% to 5 wt%, more preferably 0.1 wt% to 5 wt%, and the first compound may have 30 wt% to 60 wt%, preferably 40 wt% to 60 wt%, more preferably 40 wt% to 50 wt%, or 45 wt% to 55 wt%, but is not limited thereto.

[0324] The second EML 1090b in the second pixel region P2 and the third EML 1090c in the third pixel region P3 may each include a matrix and a dopant. For example, in each of the second EML 1090b in the second pixel region P2 and the third EML 1090c in the third pixel region P3, the dopant may include at least one of a phosphorescent compound, a fluorescent compound, and a delayed fluorescence compound.

[0325] Figure 10 The OLED D5 emits green, red, and blue light from the first pixel region P1 to the third pixel region P3, respectively, so that ( Figure 9 The organic light-emitting display device 1000 can provide full-color images.

[0326] The organic light-emitting display device 1000 may further include color filter layers corresponding to the first pixel region P1 to the third pixel region P3 to improve color purity. For example, the color filter layers may include a first color filter layer corresponding to the first pixel region P1, such as a green color filter layer; a second color filter layer corresponding to the second pixel region P2, such as a red color filter layer; and a third color filter layer corresponding to the third pixel region P3, such as a blue color filter layer.

[0327] In the bottom-emitting organic light-emitting display device 1000, a color filter layer can be disposed between the OLED D5 and the substrate 1010. On the other hand, in the top-emitting organic light-emitting display device 1000, the color filter layer can be disposed above or above the OLED D5.

[0328] Figure 11 This is a schematic cross-sectional view of an organic light-emitting display device according to the eighth embodiment of this disclosure.

[0329] like Figure 11As shown, the organic light-emitting display device 1100 includes a substrate 1110 defining first to third pixel regions P1, P2, and P3 therein; a TFT Tr above the substrate 1110; an OLED D disposed above and connected to the TFT Tr; and a color filter layer 1120 corresponding to the first pixel regions P1 to the third pixel regions P3. For example, the first to third pixel regions P1, P2, and P3 can be green pixel regions, red pixel regions, and blue pixel regions, respectively.

[0330] The substrate 1110 can be a glass substrate or a flexible substrate. For example, the flexible substrate can be a polyimide (PI) substrate, a polyethersulfone (PES) substrate, a polyethylene naphthalate (PEN) substrate, a polyethylene terephthalate (PET) substrate, or a polycarbonate (PC) substrate.

[0331] TFT Tr is formed on substrate 1110. Alternatively, a buffer layer (not shown) may be formed on substrate 1110, and TFT Tr may be formed on the buffer layer.

[0332] For example Figure 2 As explained, a TFT Tr can include a semiconductor layer, a gate, a source, and a drain, and can be used as a driving element.

[0333] Furthermore, a color filter layer 1120 is disposed on the substrate 1110. For example, the color filter layer 1120 may include a first color filter layer 1122 corresponding to a first pixel region P1, a second color filter layer 1124 corresponding to a second pixel region P2, and a third color filter layer 1126 corresponding to a third pixel region P3. The first to third color filter layers 1122, 1124, and 1126 may be a green color filter layer, a red color filter layer, and a blue color filter layer, respectively. For example, the first color filter layer 1122 may include at least one of a green dye and a green pigment, and the second color filter layer 1124 may include at least one of a red dye and a red pigment. The third color filter layer 1126 may include at least one of a blue dye and a blue pigment.

[0334] A planarization layer (or passivation layer) 1150 is formed on the TFT Tr and the color filter layer 1120. The planarization layer 1150 has a flat top surface and includes a drain contact hole 1152 that exposes the drain of the TFT Tr.

[0335] OLED D is disposed on planarization layer 1150 and corresponds to color filter layer 1120. OLED D includes a first electrode 1160, an emissive layer 1162, and a second electrode 1164. The first electrode 1160 is connected to the drain of TFT Tr, and the emissive layer 1162 and the second electrode 1164 are sequentially stacked on the first electrode 1160. OLED D emits white light in each of the first pixel region P1 to the third pixel region P3.

[0336] The first electrode 1160 is formed separately in the first pixel region P1 to the third pixel region P3, and the second electrode 1164 is formed integrally to cover the first pixel region P1 to the third pixel region P3.

[0337] The first electrode 1160 is one of the anode and the cathode, and the second electrode 1164 is the other of the anode and the cathode. In addition, the first electrode 1160 can be a light-transmitting electrode (or a semi-transparent electrode), and the second electrode 1164 can be a reflective electrode.

[0338] For example, the first electrode 1160 may be an anode and may comprise a transparent conductive oxide material layer formed of a transparent conductive oxide (TCO) material having a relatively high work function. The second electrode 1164 may be a cathode and may comprise a metallic material layer formed of a low-resistance metallic material having a relatively low work function. For example, the transparent conductive oxide material layer of the first electrode 1160 may comprise at least one of indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), tin oxide (SnO), zinc oxide (ZnO), indium copper oxide (ICO), or aluminum zinc oxide (Al:ZnO, AZO), and the second electrode 1164 may comprise Al, Mg, Ca, Ag, alloys thereof such as Mg-Ag alloys, or combinations thereof.

[0339] A light-emitting layer 1162, serving as a light-emitting unit, is formed on the first electrode 1160. The light-emitting layer 1162 includes at least two light-emitting portions that emit light of different colors. Each light-emitting portion may have a single-layer structure of an EML. Alternatively, each light-emitting portion may further include at least one of HIL, HTL, EBL, HBL, ETL, and EIL sequentially stacked between the first electrode 1060 and the EML. Furthermore, the light-emitting layer 1162 may further include a charge-generating layer (CGL) between each light-emitting portion.

[0340] The EML of one of the luminescent parts includes a first compound represented by Formula 1-1 as a delayed fluorescence material and a second compound represented by Formula 2-1 as a fluorescent material. That is, the EML of one of the luminescent parts includes a delayed fluorescence material and a fluorescent material. The EML of one of the luminescent parts may further include a third compound as a matrix. The third compound may be represented by Formula 3-1.

[0341] A dam layer 1166 is formed on the planarization layer 1150 to cover the edge of the first electrode 1160. That is, the dam layer 1166 is located at the boundary between the first pixel region P1 and the third pixel region P3 and exposes the center of the first electrode 1160 in the first pixel region P1 to the third pixel region P3. As described above, since the OLED D emits white light in the first pixel region P1 to the third pixel region P3, the light-emitting layer 1162 can be formed as a common layer in the first pixel region P1 to the third pixel region P3 without separation within the first pixel region P1 to the third pixel region P3. The dam layer 1166 can be formed to prevent current leakage at the edge of the first electrode 1160 and can be omitted.

[0342] Although not shown, the organic light-emitting display device 1100 may further include an encapsulation film formed on the second electrode 1164 to prevent moisture from penetrating into the OLED D. Furthermore, the organic light-emitting display device 1100 may further include a polarizing plate below the substrate 1110 to reduce ambient light reflection.

[0343] exist Figure 11 In the organic light-emitting display device 1100, the first electrode 1160 is a transparent electrode (transparent electrode), and the second electrode 1164 is a reflective electrode. Furthermore, a color filter layer 1120 is located between the substrate 1110 and the OLED D. That is, the organic light-emitting display device 1100 is a bottom-emitting type.

[0344] Alternatively, in the organic light-emitting display device 1100, the first electrode 1160 may be a reflective electrode, and the second electrode 1164 may be a transparent electrode (or a translucent electrode). In this case, the color filter layer 1120 is located above or on the OLED D.

[0345] In the organic light-emitting display device 1100, the OLED D emits white light in the first pixel region P1 to the third pixel region P3, and the white light passes through the first to third color filter layers 1122, 1124 and 1126. Therefore, green light, red light and blue light are displayed in the first pixel region P1 to the third pixel region P3, respectively.

[0346] Although not shown, a color conversion layer can be formed between the OLED D and the color filter layer 1120. The color conversion layer may include a green conversion layer, a red conversion layer, and a blue conversion layer corresponding to the first pixel region P1 to the third pixel region P3, respectively, allowing white light from the OLED D to be converted into green, red, and blue light. The color conversion layer may include quantum dots. Therefore, the color purity of the OLED D can be further improved.

[0347] A color conversion layer may be included to replace the color filter layer 1120.

[0348] Figure 12 This is a schematic cross-sectional view of an OLED according to the ninth embodiment of this disclosure.

[0349] like Figure 12 As shown, the OLED D6 includes a first electrode 1160 and a second electrode 1164 facing each other, and a light-emitting layer 1162 between them.

[0350] The first electrode 1160 can be an anode, and the second electrode 1164 can be a cathode. The first electrode 1160 is a transparent electrode (transparent electrode), and the second electrode 1164 is a reflective electrode.

[0351] The light-emitting layer 1162 includes a first light-emitting portion 1210 containing a first EML 1220, a second light-emitting portion 1230 containing a second EML 1240, and a third light-emitting portion 1250 containing a third EML 1260. Furthermore, the light-emitting layer 1162 may further include a first CGL 1270 between the first light-emitting portion 1210 and the second light-emitting portion 1230, and a second CGL 1280 between the first light-emitting portion 1210 and the third light-emitting portion 1250.

[0352] The first light-emitting portion 1270 is located between the first light-emitting portion 1210 and the second light-emitting portion 1230, and the second light-emitting portion 1280 is located between the first light-emitting portion 1210 and the third light-emitting portion 1250. That is, the third light-emitting portion 1250, the second light-emitting portion 1280, the first light-emitting portion 1210, the first light-emitting portion 1270, and the second light-emitting portion 1230 are sequentially stacked on the first electrode 1160. In other words, the first light-emitting portion 1210 is located between the first light-emitting portion 1270 and the second light-emitting portion 1280, while the second light-emitting portion 1230 is located between the first light-emitting portion 1270 and the second electrode 1164. The third light-emitting portion 1250 is located between the second light-emitting portion 1280 and the first electrode 1160.

[0353] The first light-emitting portion 1210 may further include a first HTL 1210a below the first EML 1220 and a first ETL 1210b above the first EML 1220. That is, the first HTL 1210a may be located between the first EML 1220 and the second CGL 1270, and the first ETL 1210b may be located between the first EML 1220 and the first CGL 1270.

[0354] Furthermore, the first light-emitting portion 1210 may further include an EBL (not shown) between the first HTL 1210a and the first EML 1220 and an HBL (not shown) between the first ETL 1210b and the first EML 1220.

[0355] The second light-emitting portion 1230 may further include a second HTL 1230a below the second EML 1240, a second ETL 1230b above the second EML 1240, and an EIL 1230c on the second ETL 1230b. That is, the second HTL 1230a may be located between the second EML 1240 and the first CGL 1270, and the second ETL 1230b and EIL 1230c may be located between the second EML 1240 and the second electrode 1164.

[0356] Furthermore, the second light-emitting portion 1230 may further include an EBL (not shown) between the second HTL 1230a and the second EML 1240, and an HBL (not shown) between the second ETL 1230b and the second EML 1240.

[0357] The third light-emitting portion 1250 may further include a third HTL 1250b below the third EML 1260, a HIL 1250a below the third HTL 1250b, and a third ETL 1250c above the third EML 1260. That is, HIL 1250a and the third HTL 1250b may be located between the first electrode 1160 and the third EML 1260, and the third ETL 1250c may be located between the third EML 1260 and the second CGL 1280.

[0358] Furthermore, the third light-emitting unit 1250 may further include an EBL (not shown) between the third HTL 1250b and the third EML 1260 and an HBL (not shown) between the third ETL 1250c and the third EML 1260.

[0359] One of the first through third EMLs 1220, 1240, and 1260 is a green EML. Another of the first through third EMLs 1220, 1240, and 1260 can be a blue EML, and yet another of the first through third EMLs 1220, 1240, and 1260 can be a red EML.

[0360] For example, the first EML 1220 can be a green EML, the second EML 1240 can be a blue EML, and the third EML 1260 can be a red EML. Alternatively, the first EML 1220 can be a green EML, the second EML 1240 can be a red EML, and the third EML 1260 can be a blue EML.

[0361] The first EML 1220 comprises a first compound as a delayed fluorescence material and a second compound as a fluorescent material. The first EML 1220 may further comprise a third compound as a matrix. The first compound is represented by Formula 1-1, the second compound by Formula 2-1, and the third compound by Formula 3-1.

[0362] In the first EML 1220, the weight percentage of the first compound can be greater than that of the second compound, and can be equal to or greater than that of the third compound. When the weight percentage of the first compound is greater than that of the second compound, an energy transfer from the first compound to the second compound is effectively generated. For example, in the first EML 1220, the second compound can have a weight percentage of 0.01% to 10% by weight, preferably 0.01% to 5% by weight, more preferably 0.1% to 5% by weight, and the first compound can have a weight percentage of 30% to 60% by weight, preferably 40% to 60% by weight, more preferably 40% to 50% by weight, or 45% to 55% by weight, but is not limited thereto.

[0363] The second EML 1240 includes a matrix and a blue dopant (or a red dopant), and the third EML 1260 includes a matrix and a red dopant (or a blue dopant). For example, in each of the second EML 1240 and the third EML 1260, the dopant may include at least one of a phosphorescent compound, a fluorescent compound, and a delayed fluorescence compound.

[0364] OLED D6 in ( Figure 11 White light is emitted from the first pixel region P1 to the third pixel region P3, and the white light passes through the first pixel region P1 to the third pixel region P3. Figure 11 The color filter layer 1120. Therefore, ( Figure 11 The organic light-emitting display device 1100 can provide full-color images.

[0365] Figure 13 This is a schematic cross-sectional view of an OLED according to the tenth embodiment of the present disclosure.

[0366] like Figure 13 As shown, the OLED D7 includes a first electrode 1360 and a second electrode 1364 facing each other, and a light-emitting layer 1362 between them.

[0367] The first electrode 1360 can be an anode, and the second electrode 1364 can be a cathode. The first electrode 1360 is a transparent electrode (transparent electrode), and the second electrode 1364 is a reflective electrode.

[0368] The light-emitting layer 1362 includes a first light-emitting portion 1410 containing a first EML 1420, a second light-emitting portion 1430 containing a second EML 1440, and a third light-emitting portion 1450 containing a third EML 1460. Furthermore, the light-emitting layer 1362 may further include a first CGL 1470 between the first light-emitting portion 1410 and the second light-emitting portion 1430, and a second CGL 1480 between the first light-emitting portion 1410 and the third light-emitting portion 1450.

[0369] The first EML 1420 includes a lower EML 1420a and an upper EML 1420b. That is, the lower EML 1420a is located closer to the first electrode 1360, and the upper EML 1420b is located closer to the second electrode 1364.

[0370] The first light-emitting portion 1470 is located between the first light-emitting portion 1410 and the second light-emitting portion 1430, and the second light-emitting portion 1480 is located between the first light-emitting portion 1410 and the third light-emitting portion 1450. That is, the third light-emitting portion 1450, the second light-emitting portion 1480, the first light-emitting portion 1410, the first light-emitting portion 1470, and the second light-emitting portion 1430 are sequentially stacked on the first electrode 1360. In other words, the first light-emitting portion 1410 is located between the first light-emitting portion 1470 and the second light-emitting portion 1480, while the second light-emitting portion 1430 is located between the first light-emitting portion 1470 and the second electrode 1360. The third light-emitting portion 1450 is located between the second light-emitting portion 1480 and the first electrode 1360.

[0371] The first light-emitting portion 1410 may further include a first HTL 1410a below the first EML 1420 and a first ETL 1410b above the first EML 1420. That is, the first HTL 1410a may be located between the first EML 1420 and the second CGL 1470, and the first ETL 1410b may be located between the first EML 1420 and the first CGL 1470.

[0372] Furthermore, the first light-emitting portion 1410 may further include an EBL (not shown) between the first HTL 1410a and the first EML 1420 and an HBL (not shown) between the first ETL 1410b and the first EML 1420.

[0373] The second light-emitting portion 1430 may further include a second HTL 1430a below the second EML 1440, a second ETL 1430b above the second EML 1440, and an EIL 1430c on the second ETL 1430b. That is, the second HTL 1430a may be located between the second EML 1440 and the first CGL 1470, and the second ETL 1430b and EIL 1430c may be located between the second EML 1440 and the second electrode 1364.

[0374] Furthermore, the second light-emitting portion 1430 may further include an EBL (not shown) between the second HTL 1430a and the second EML 1440, and an HBL (not shown) between the second ETL 1430b and the second EML 1440.

[0375] The third light-emitting portion 1450 may further include a third HTL 1450b below the third EML 1460, a HIL 1450a below the third HTL 1450b, and a third ETL 1450c above the third EML 1460. That is, HIL 1450a and the third HTL 1450b may be located between the first electrode 1360 and the third EML 1460, and the third ETL 1450c may be located between the third EML 1460 and the second CGL 1480.

[0376] Furthermore, the third light-emitting unit 1450 may further include an EBL (not shown) between the third HTL 1450b and the third EML 1460, and an HBL (not shown) between the third ETL 1450c and the third EML 1460.

[0377] One of the lower EML 1420a and upper EML 1420b of the first EML 1420 is a green EML, and the other of the lower EML 1420a and upper EML 1420b of the first EML 1420 can be a red EML. That is, the green EML (or red EML) and the red EML (or green EML) are stacked sequentially to form the first EML 1420.

[0378] For example, the upper EML 1420b, as a green EML, comprises a first compound as a delayed fluorescence material and a second compound as a fluorescent material. The upper EML 1420b may further comprise a third compound as a matrix. The first compound is represented by Formula 1-1, the second compound by Formula 2-1, and the third compound by Formula 3-1.

[0379] In EML 1420b, the weight percentage of the first compound can be greater than that of the second compound, and can be equal to or greater than that of the third compound. When the weight percentage of the first compound is greater than that of the second compound, an energy transfer from the first compound to the second compound is effectively achieved. For example, in EML 1420b, the second compound can have a weight percentage of 0.01% to 10%, preferably 0.01% to 5%, more preferably 0.1% to 5%, and the first compound can have a weight percentage of 30% to 60%, preferably 40% to 60%, more preferably 40% to 50%, or 45% to 55%, but is not limited thereto.

[0380] The lower EML 1420a, which is a red EML, may include a matrix and a red dopant.

[0381] Each of the second EML 1440 and the third EML 1460 can be a blue EML. Each of the second EML 1440 and the third EML 1460 can include a matrix and a blue dopant. The matrix and dopant of the second EML 1440 can be the same as those of the third EML 1460. Alternatively, the matrix and dopant of the second EML 1440 can be different from those of the third EML 1460. For example, the dopant in the second EML 1440 can have a different emission efficiency and / or emission wavelength than the dopant in the third EML 1460.

[0382] In each of the lower EML 1420a, the second EML 1440 and the third EML 1460, the dopant may include at least one of a phosphorescent compound, a fluorescent compound and a delayed fluorescence compound.

[0383] OLED D7 in ( Figure 11 White light is emitted from the first pixel region P1 to the third pixel region P3, and the white light passes through the first pixel region P1 to the third pixel region P3. Figure 11 The color filter layer 1120. Therefore, ( Figure 11 The organic light-emitting display device 1100 can provide full-color images.

[0384] exist Figure 13 In this OLED D7, a triple-layer (triple-layer) structure is provided, comprising a second EML 1440 and a third EML 1460 as the blue EML, and a first EML 1420. Alternatively, one of the second EML 1440 and the third EML 1460 may be omitted, allowing the OLED D7 to have a dual-layer (double-layer) structure.

[0385] It will be apparent to those skilled in the art that various modifications and variations can be made to this disclosure without departing from the spirit or scope thereof. Therefore, this disclosure is intended to cover such modifications and variations as long as they fall within the scope of the appended claims and their equivalents.

Claims

1. An organic light emitting diode comprising: a first electrode; a second electrode facing the first electrode; and a first light emitting material layer comprising a first compound and a second compound and disposed between the first electrode and the second electrode, wherein the first compound is represented by Formula 1-3: [Formula 1-3] wherein X 2 is one of NR 8, O, and S, and R 8 is a substituted or unsubstituted C 6 to C 30 aryl, wherein Y is selected from the group consisting of cyano (-CN), nitro (-NO 2), halogen, and C 1 to C 20 alkyl substituted with at least one of cyano, nitro, and halogen, wherein the second compound is represented by Formula 2-1: [Formula 2-1] wherein R 11 to R 14 are each independently selected from the group consisting of a substituted or unsubstituted C 1 to C 20 alkyl and a substituted or unsubstituted C 6 to C 30 aryl, wherein R 21 to R 28, R 31 to R 38, and R 41 to R 48 are each independently selected from the group consisting of hydrogen, a substituted or unsubstituted C 1 to C 20 alkyl, and a substituted or unsubstituted C 6 to C 30 aryl, wherein R 29, R 30, R 39, R 40, R 49, and R 50 are each independently selected from the group consisting of hydrogen, a substituted or unsubstituted C 1 to C 20 alkyl, and a substituted or unsubstituted C 6 to C 30 aryl, or at least one pair of R 29 and R 30, R 39 and R 40, and R 49 and R 50 are linked to each other to form a ring, wherein m 1 to m 3 are each independently 0 or 1, and at least one of m 1 to m 3 is 1, and wherein b 1 and b 4 are each independently an integer from 0 to 4, and b 2 and b 3 are each independently an integer from 0 to 3. 2.The organic light emitting diode of claim 1, wherein the first compound is one of compounds in Formula 1-4: [Formula 1-4] 3.The organic light emitting diode of claim 1, wherein the second compound is one of compounds in Formula 2-2: [Formula 2-2] 4.The organic light emitting diode of claim 1, wherein the weight % of the first compound is greater than the weight % of the second compound. 5.The organic light emitting diode of claim 1, wherein the first light emitting material layer further comprises a third compound as a first host. 6.The organic light emitting diode of claim 5, wherein the third compound is represented by Formula 3-1: [Formula 3-1] wherein R 51 and R 52 are each independently selected from deuterium, tritium, a substituted or unsubstituted C 1 to C 20 alkyl, a substituted or unsubstituted C 6 to C 30 aryl, and a substituted or unsubstituted C 3 to C 40 heteroaryl, or adjacent two of R 51 and R 52 are linked to each other to form an aromatic ring or a heteroaromatic ring, wherein c 1 and c 2 are each independently an integer from 0 to 4, and wherein Ar 1 and Ar 2 are each independently selected from Formulae 3-2 to 3-4: [Formula 3-2] [Formula 3-3] [Formula 3-4] and 7.The organic light emitting diode of claim 6, wherein the third compound is represented by Formula 3-5: [Formula 3-5] ​ wherein X3is one of O, S, and NR53, and R53is selected from the group consisting of hydrogen, deuterium, tritium, substituted or unsubstituted C1to C20alkyl, substituted or unsubstituted C6to C30aryl, and substituted or unsubstituted C3to C40heteroaryl.

8. The organic light emitting diode of claim 6, wherein the third compound is one of the compounds in Formula 3-6: [Formula 3-6] 9. The organic light emitting diode of claim 1, wherein the first light emitting material layer comprises a first layer and a second layer, and the second layer is between the first layer and the second electrode, and wherein the first layer comprises the second compound and a first host, and the second layer comprises the first compound and a second host.

10. The organic light emitting diode of claim 9, wherein the first light emitting material layer further comprises a third layer, the third layer comprises the second compound and a third host and is between the second layer and the second electrode.

11. The organic light emitting diode of claim 1, further comprising: a second light emitting material layer between the first electrode and the first light emitting material layer; and a charge generation layer between the first light emitting material layer and the second light emitting material layer, wherein the second light emitting material layer is one of a red light emitting material layer, a green light emitting material layer, and a blue light emitting material layer.

12. An organic light emitting device comprising: a substrate; the organic light emitting diode of any one of claims 1-11 disposed over the substrate; and an encapsulation film encapsulating the organic light emitting diode. ​ ​

Images