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

Abstract

An organic light emitting diode comprising: a reflective electrode; a transparent electrode facing the reflective electrode; and an organic light emitting layer comprising a first light emitting portion and a second light emitting portion and located between the reflective electrode and the transparent electrode, wherein each of the first light emitting portion and the second light emitting portion comprises a phosphorescent light emitting layer and a fluorescent light emitting layer, and wherein in at least one of the first light emitting portion and the second light emitting portion, the fluorescent light emitting layer is positioned closer to the transparent electrode than the phosphorescent light emitting layer.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2021-0185242, filed in Korea on December 22, 2021, which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure relates to an organic light-emitting diode (OLED), and more specifically, to an organic light-emitting diode with high display performance and an organic light-emitting display device including the organic light-emitting diode. Background Technology

[0004] The demand for flat panel display devices with small footprints is increasing. Among flat panel display devices, organic light-emitting display technology, including organic light-emitting diodes (OLEDs) and also referred to as organic electroluminescent devices, is developing rapidly.

[0005] The OLED emits light by injecting electrons from the cathode (which acts as an electron injection electrode) and holes from the anode (which acts as a hole injection electrode) into the light-emitting material layer. The electrons and holes combine to generate excitons, and the excitons are then transformed from an excited state to a 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 luminescence. Summary of the Invention

[0007] Therefore, embodiments of this disclosure relate to an OLED and an organic light-emitting display 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 an OLED and organic light-emitting display device with high display performance.

[0009] Additional features and aspects will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the inventive concept provided herein. Other features and aspects of the present disclosure concept may be realized and obtained by means of structures particularly emphasized in or derived therefrom in the written description, as well as the claims of this disclosure and the accompanying drawings.

[0010] To achieve these and other advantages of embodiments according to this disclosure, as described herein, one aspect of this disclosure is an organic light-emitting diode (OLED) comprising: a reflective electrode; a transparent electrode facing the reflective electrode; and an organic light-emitting layer comprising a first light-emitting portion and a second light-emitting portion and located between the reflective electrode and the transparent electrode, wherein each of the first light-emitting portion and the second light-emitting portion comprises a phosphorescent light-emitting layer and a fluorescent light-emitting layer, and wherein in at least one of the first light-emitting portion and the second light-emitting portion, the fluorescent light-emitting layer is positioned closer to the transparent electrode than the phosphorescent light-emitting layer.

[0011] Another aspect of this disclosure is an organic light-emitting display device, comprising: a substrate including a red pixel region, a green pixel region, and a blue pixel region; and an organic light-emitting diode (OLED) disposed on or above the substrate and located in the green pixel region, the OLED including: a reflective electrode; a transparent electrode facing the reflective electrode; and an organic light-emitting layer including a first light-emitting portion and a second light-emitting portion and located between the reflective electrode and the transparent electrode, wherein each of the first light-emitting portion and the second light-emitting portion includes a phosphorescent light-emitting layer and a fluorescent light-emitting layer, and wherein in at least one of the first light-emitting portion and the second light-emitting portion, the fluorescent light-emitting layer is positioned closer to the transparent electrode than the phosphorescent light-emitting layer.

[0012] It should be understood that the above general description and the following detailed description are exemplary and explanatory, intended to provide further explanation of the claimed inventive concept. Attached Figure Description

[0013] The accompanying drawings are included in and form part of this application to provide a further understanding of the present disclosure. These drawings illustrate embodiments of the present disclosure and, together with the specification, serve to explain the principles of the present disclosure.

[0014] Figure 1 This is a circuit diagram of the organic light-emitting display device disclosed herein.

[0015] Figure 2 This is a schematic cross-sectional view of an organic light-emitting display device according to the first embodiment of this disclosure.

[0016] Figure 3 This is a schematic cross-sectional view of an OLED according to the second embodiment of this disclosure.

[0017] Figure 4 This is a schematic cross-sectional view of an OLED according to the third embodiment of this disclosure.

[0018] Figure 5This is a schematic cross-sectional view of an OLED according to the fourth embodiment of this disclosure.

[0019] Figures 6A to 6E It is the PL spectrum of the emitting element (dopant) of the OLED used in this disclosure.

[0020] Figure 7 This is a schematic cross-sectional view of an organic light-emitting display device according to the fifth embodiment of this disclosure.

[0021] Figure 8 This is a schematic cross-sectional view of an organic light-emitting display device according to the sixth embodiment of this disclosure. Detailed Implementation

[0022] Reference will now be made in detail to some embodiments and preferred implementations shown in the accompanying drawings.

[0023] Figure 1 This is a circuit diagram of the organic light-emitting display device disclosed herein.

[0024] like Figure 1 As 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.

[0025] 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.

[0026] In the organic light-emitting display device, when the switch TFT Ts is turned on by a gate signal applied to the gate line GL, a data signal from the data line DL is applied to the gate of the driving TFT Td and the electrode of the storage capacitor Cst.

[0027] When the driving TFT Td is turned on by a data signal, current is supplied to the OLED D from the power line PL. As a result, the OLED D emits light. In this case, when the driving TFT Td is turned on, the current level applied to the OLED D from the power line PL is determined, thereby enabling the OLED D to produce grayscale.

[0028] 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 when the switching TFT Ts is turned off, the current level applied to the OLED D from the power line PL is maintained until the next frame.

[0029] Therefore, the organic light-emitting display device displays the desired image.

[0030] 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.

[0031] like Figure 2 As shown, the organic light-emitting display device 100 includes a substrate 110, a TFT Tr on or above the substrate 110, a planarization layer 150 covering the TFT Tr, and an OLEDD located on the planarization layer 150 and connected to the TFT Tr. Red pixel regions, green pixel regions, and blue pixel regions can be defined on the substrate 110.

[0032] The substrate 110 may be a glass substrate or a flexible substrate. For example, the flexible substrate may be one of a polyimide (PI) substrate, a polyethersulfone (PES) substrate, a polyethylene naphthalate (PEN) substrate, a polyethylene terephthalate (PET) substrate, and a polycarbonate (PC) substrate.

[0033] A buffer layer 122 is formed on the substrate, and the TFT Tr is formed on the buffer layer 122. The buffer layer 122 may be omitted. For example, the buffer layer 122 may be formed of an inorganic insulating material, such as silicon oxide or silicon nitride.

[0034] A semiconductor layer 120 is formed on the buffer layer 122. The semiconductor layer 120 may comprise an oxide semiconductor material or polysilicon.

[0035] 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 polycrystalline silicon, impurities can be doped onto both sides of the semiconductor layer 120.

[0036] 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.

[0037] A gate 130, formed of a conductive material such as a metal, is formed on the gate insulating layer 124 corresponding to the center of the semiconductor layer 120. 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.

[0038] An interlayer insulating layer 132 is formed on the gate 130 and over the entire surface of the substrate 110. 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 photopropylene).

[0039] The interlayer insulating layer 132 includes first and second contact holes 134 and 136 exposing both sides of the semiconductor layer 120. The first and second contact holes 134 and 136 are located on both sides of the gate 130 and spaced apart from the gate 130.

[0040] The first and second contact holes 134 and 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 and second contact holes 134 and 136 are formed only through the interlayer insulating layer 132.

[0041] Source 144 and drain 146, formed of conductive material such as metal, are formed on the interlayer insulating layer 132.

[0042] The source 144 and the 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 and second contact holes 134 and 136, respectively.

[0043] The semiconductor layer 120, gate 130, source 144, and drain 146 constitute a TFT Tr. The TFT Tr serves as a driving element. That is, the TFT Tr drives the TFT Td (…). Figure 1 ).

[0044] 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.

[0045] Alternatively, in the TFT Tr, the gate may be located below the semiconductor layer, and the source and drain may be located above the semiconductor layer, allowing the TFT Tr to have an inverted staggered structure. In this case, the semiconductor layer may comprise amorphous silicon.

[0046] Although not shown, the gate lines and data lines intersect each other to define a pixel area, and the switching TFT is formed to connect to the gate lines and data lines. The switching TFT is connected to the TFT Tr, which serves as a driving element. Furthermore, a power line parallel to and spaced apart from one of the gate lines and data lines, and a storage capacitor for maintaining the gate voltage of the TFT Tr within a frame, may be further formed.

[0047] A planarization layer 150 is formed on the entire surface of the substrate 110 to cover the source and drain electrodes 144 and 146. The planarization layer 150 provides a flat top surface and has a drain contact hole 152 that exposes the drain electrode 146 of the TFT Tr.

[0048] 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 organic light-emitting layer 220, and a second electrode 230. The organic light-emitting 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, green, and blue light, respectively.

[0049] The first electrode 210 is formed in each pixel region. The first electrode 210 may be an anode and may include a transparent conductive oxide material layer and a reflective layer. The transparent conductive oxide material layer may be formed of a conductive material such as transparent conductive oxide (TCO) and has a relatively high work function. That is, the first electrode 210 may be a reflective electrode.

[0050] Alternatively, the first electrode 210 may have a single-layer structure with a transparent conductive oxide material layer. That is, the first electrode 210 may be a transparent electrode.

[0051] For example, the transparent conductive oxide material layer can be formed from one of indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), tin oxide (SnO), zinc oxide (ZnO), cerium-doped indium oxide (ICO), aluminum-doped zinc oxide (Al:ZnO, AZO), and the reflective layer can be formed from silver (Ag), an alloy of Ag with palladium (Pd), copper (Cu), indium (In), and neodymium (Nd), as well as an aluminum-palladium-copper (APC) alloy. For example, the first electrode 210 can have an ITO / Ag / ITO or ITO / APC / ITO structure.

[0052] 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 exposes the center of the first electrode 210 in the pixel region.

[0053] The organic light-emitting layer 220, serving as a light-emitting unit, is formed on the first electrode 210. The organic light-emitting layer 220 includes a first light-emitting portion comprising a first green light-emitting material layer (EML) and a second light-emitting portion comprising a second green EML. That is, the organic light-emitting layer 220 has a multilayer structure, such that the OLED D has a series structure.

[0054] Each of the first and second light-emitting portions may further include at least one of a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), a hole blocking layer (HBL), an electron transport layer (ETL), and an electron injection layer (EIL) to have a multilayer structure. Furthermore, the organic light-emitting layer may also include a charge generation layer (CGL) located between the first and second light-emitting portions.

[0055] As described below, in the OLED D within the green pixel region, each of the first and second green EMLs includes a fluorescent emitting layer comprising a delayed fluorescence compound and a fluorescent compound, and a phosphorescent emitting layer comprising a phosphorescent compound. Therefore, the OLED D has advantages in luminous efficiency, full width at half maximum (FWHM), and lifetime.

[0056] The second electrode 230 is formed above the substrate 110 having the organic light-emitting layer 220. 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). The second electrode 230 can have a thin profile, for example, 10 to 30 nm, to be transparent (or translucent).

[0057] Although not shown, the OLED D may also include a capping layer on the second electrode 230. The luminous efficiency of the OLED D can be further improved by the capping layer.

[0058] 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 sequentially.

[0059] 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, the color filters may be located on or above the OLED D or encapsulation film 170.

[0060] Furthermore, the organic light-emitting display device 100 may also include a cover window (not shown) on or above the encapsulation film 170 or the color filter. In this case, the substrate 110 and the cover window have flexible properties, thereby providing a flexible organic light-emitting display device.

[0061] Figure 3 This is a schematic cross-sectional view of an organic light-emitting diode according to the second embodiment of this disclosure.

[0062] like Figure 3 As shown, the OLED D1 includes a first electrode 210 as a reflective electrode, a second electrode 230 as a transparent electrode (or semi-transparent electrode) facing the first electrode 210, and an organic light-emitting layer 220 between the two. The organic light-emitting layer 220 includes a first light-emitting portion 310 and a second light-emitting portion 350, wherein the first light-emitting portion 310 includes a first EML 340 comprising the first light-emitting layer 320 and the second light-emitting layer 330, and the second light-emitting portion 350 includes a second EML 380 comprising a third light-emitting layer 360 and a fourth light-emitting layer 370. Furthermore, the organic light-emitting layer 220 may also include a CGL 390 located between the first and second light-emitting portions 310 and 350. Additionally, the OLED D1 may also include a capping layer 290 for enhancing (improving) luminous efficiency.

[0063] The organic light-emitting display device may include a red pixel region, a green pixel region, and a blue pixel region, and the OLED D1 is located in the green pixel region.

[0064] The first electrode 210 can be an anode, and the second electrode 230 can be a cathode. The first electrode 210 is a reflective electrode, and the second electrode 230 is a transparent electrode (or a semi-transparent electrode). For example, the first electrode 210 can have an ITO / Ag / ITO structure, and the second electrode 230 can be formed of MgAg or Al. That is, the first electrode 210 can have a first transmittance, and the second electrode 230 can have a second transmittance greater than the first transmittance.

[0065] In the first light-emitting portion 310, the first light-emitting layer 320 is located between the first electrode 210 and the second light-emitting layer 330. That is, the first light-emitting layer 310 is positioned closer to the first electrode 210, and the second light-emitting layer 310 is positioned closer to the second electrode 230. The first light-emitting layer 320 is a phosphorescent light-emitting layer, and the second light-emitting layer 330 is a fluorescent light-emitting layer.

[0066] In the second light-emitting portion 350, the fourth light-emitting layer 370 is located between the second electrode 230 and the third light-emitting layer 360. That is, the third light-emitting layer 360 is positioned closer to the first electrode 210, and the fourth light-emitting layer 370 is positioned closer to the second electrode 230. The third light-emitting layer 360 is a fluorescent light-emitting layer, and the fourth light-emitting layer 370 is a phosphorescent light-emitting layer. Specifically, in the first light-emitting portion 310, the second light-emitting layer 330, which is a fluorescent light-emitting layer, is positioned closer to the second electrode 230, which is a transparent electrode (or a semi-transparent electrode), while in the second light-emitting portion 350, the fourth light-emitting layer, which is a phosphorescent light-emitting layer, is positioned closer to the second electrode 230, which is a transparent electrode.

[0067] The first luminescent layer 320 includes a first compound 322 as a first host and a second compound 324 as a first phosphorescent dopant (or first phosphorescent emitter). The second luminescent layer 330 includes a third compound 332 as a second host, a fourth compound 334 as an auxiliary host (or auxiliary dopant), and a fifth compound 336 as a first fluorescent dopant (or first fluorescent emitter). The fourth compound 334 is a delayed fluorescence compound.

[0068] The third luminescent layer 360 includes a sixth compound 362 as a third host, a seventh compound 364 as an auxiliary host, and an eighth compound 366 as a second fluorescent dopant. The seventh compound 364 is a delayed fluorescence compound. The fourth luminescent layer 370 includes a ninth compound 372 as a fourth host and a tenth compound 374 as a second phosphorescent dopant.

[0069] Each of the first compound 322, which is the main body of the first light-emitting layer 320, the third compound 332, which is the main body of the second light-emitting layer 330, the sixth compound 362, which is the main body of the third light-emitting layer 360, and the ninth compound 372, which is the main body of the fourth light-emitting layer 370, is represented by Formula 1-1.

[0070] [Equation 1-1]

[0071]

[0072] In Formula 1-1, Ar is selected from the group consisting of substituted or unsubstituted C6-C30 aryl groups and substituted or unsubstituted C5-C30 heteroaryl groups. R1, R2, R3 and R4 are each independently selected from the group consisting of substituted or unsubstituted C1-C10 alkyl groups and substituted or unsubstituted C6-C30 aryl groups, and a1, a2, a3 and a4 are each independently an integer from 0 to 4.

[0073] In this disclosure, unless otherwise defined, the substituent may be at least one of deuterium (D), halogen, C1-C10 alkyl, and C6-C30 aryl.

[0074] 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, indene, indenoindenyl, heptalenyl, biphenyl, indacenyl, phenanthrene, benzo[a]phenanthrene, dibenzo[a]phenanthrene, azulel, pyrene, fluoranyl, triphenyl, chrysenyl, tetraphenyl, tetrasenyl, picenyl, pentaphenyl, pentaphenyl, fluorenyl, indeno[a]fluorenyl, and spirofluorenyl.

[0075] In this disclosure, C5 to C30 heteroaryl groups may be selected from the group consisting of: pyrroloyl, pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, tetraazinyl, imidazolyl, pyrazolyl, indoleyl, isoindoleyl, indazoleyl, indazinyl, pyrroloazinyl, carbazoleyl, benzo[carbazoleyl], dibenzo[carbazoleyl], indole[carbazoleyl], indo[carbazoleyl], benzo[furan]carbazoleyl, benzo[thiophene]carbazoleyl, quinolinyl, isoquinolinyl, phthalazinyl, quinoxalinyl, phenanthrynyl, phenanthrynyl, pteridineyl, naphthylamine, furanyl, oxazinyl, oxazolyl, oxadiazole The following are listed: alkyl, triazolyl, dioxinyl, benzofuranyl, dibenzofuranyl, thiopyranyl, xanthenyl, benzopyranyl, isobenzopyranyl, thiazinyl, thiophenyl, benzothiophenyl, dibenzothiophenyl, difuranpyrazinyl, benzofurandibenzofuranyl, benzothienobenzothiophenyl, benzothienodibenzothiophenyl, benzothienobenzofuranyl, and benzothienodibenzofuranyl.

[0076] For example, in Formula 1-1, Ar can be either biphenylene or phenylene.

[0077] That is, the first compound 322, which is the main body of the first light-emitting layer 320, the third compound 332, which is the main body of the second light-emitting layer 330, the sixth compound 362, which is the main body of the third light-emitting layer 360, and the ninth compound 372, which is the main body of the fourth light-emitting layer 370, have the same chemical structure and may be the same or different.

[0078] Equation 1-1 can be represented by Equation 1-2.

[0079] [Equation 1-2]

[0080]

[0081] In Formula 1-2, R5 and R6 are each independently selected from the group consisting of substituted or unsubstituted C1-C10 alkyl groups and substituted or unsubstituted C6-C30 aryl groups, and a5 and a6 are each independently integers from 0 to 4. The definitions of R1, R2, R3, R4, a1, a2, a3, and a4 are the same as in Formula 1-1.

[0082] Alternatively, Equation 1-1 can be represented by Equation 1-3.

[0083] [Equation 1-3]

[0084]

[0085] In Formulas 1-3, R5 and R6 are each independently selected from the group consisting of substituted or unsubstituted C1-C10 alkyl groups and substituted or unsubstituted C6-C30 aryl groups, and a5 and a6 are each independently integers from 0 to 4. The definitions of R1, R2, R3, R4, a1, a2, a3, and a4 are the same as in Formula 1-1.

[0086] Alternatively, Equation 1-1 can be represented by Equation 1-4.

[0087] [Equations 1-4]

[0088]

[0089] In Formulas 1-4, R7 is independently selected from the group consisting of substituted or unsubstituted C1-C10 alkyl groups and substituted or unsubstituted C6-C30 aryl groups, and a7 is independently an integer from 0 to 4. The definitions of R1, R2, R3, R4, a1, a2, a3, and a4 are the same as in Formula 1-1.

[0090] That is, in the green pixel region of the OLED D1, each of the first compound 322, which is the main body of the first light-emitting layer 320, the third compound 332, which is the main body of the second light-emitting layer 330, the sixth compound 362, which is the main body of the third light-emitting layer 360, and the ninth compound 372, which is the main body of the fourth light-emitting layer 370, has a structure in which two carbazole groups are connected (bonded, linked, or joined) to a linking group, such as biphenyl or phenylene. In this case, as shown in Formulas 1-2, the performance of the OLED D1 can be further improved when the two carbazole groups are connected to the liner in a para position.

[0091] For example, each of the first compound 322, which is the main body of the first light-emitting layer 320, the third compound 332, which is the main body of the second light-emitting layer 330, the sixth compound 362, which is the main body of the third light-emitting layer 360, and the ninth compound 372, which is the main body of the fourth light-emitting layer 370, can be one of the compounds in Formula 2.

[0092] [Equation 2]

[0093]

[0094] Each of the second compound 324, which serves as the first phosphorescent dopant of the first luminescent layer 320, and the tenth compound 374, which serves as the second phosphorescent dopant of the fourth luminescent layer 370, is an iridium compound represented by Formula 3.

[0095] [Formula 3]

[0096]

[0097] In Formula 3, R11 and R12 are each independently selected from the group consisting of halogens, substituted or unsubstituted C1-C10 alkyl groups, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C5-C30 heteroaryl groups, and b1 and b2 are each independently integers from 0 to 4. R13 and R14 are each independently selected from the group consisting of hydrogen (H), halogens, substituted or unsubstituted C1-C10 alkyl groups, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C5-C30 heteroaryl groups.

[0098] For example, R11, R12, R13 and R14 are each independently C1-C10 alkyl, such as methyl or tert-butyl.

[0099] That is, the second compound 324, which is the first phosphorescent dopant of the first light-emitting layer 320, and the tenth compound 374, which is the second phosphorescent dopant of the fourth light-emitting layer 370, have the same chemical structure and may be the same or different.

[0100] For example, each of the second compound 324, which is the first phosphorescent dopant of the first luminescent layer 320, and the tenth compound 374, which is the second phosphorescent dopant of the fourth luminescent layer 370, can be one of the compounds in Formula 4.

[0101] [Formula 4]

[0102]

[0103] Each of the fourth compound 334, which serves as an auxiliary host for the second light-emitting layer 330, and the seventh compound 364, which serves as an auxiliary host for the third light-emitting layer 360, is represented by Formula 5-1.

[0104] [Equation 5-1]

[0105]

[0106] In Equation 5-1, Y is represented by Equation 5-2, where c1 is an integer from 1 to 4. When c1 is an integer of 2 or greater, Y is either the same or different.

[0107] [Equation 5-2]

[0108]

[0109] In Formula 5-2, R21 and R22 are each independently selected from the group consisting of substituted or unsubstituted C1-C10 alkyl groups, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C5-C30 heteroaryl groups, or at least one of two adjacent R21s and two adjacent R22s is interconnected to form an aromatic ring or a heteroaromatic ring. Furthermore, c2 and c3 are each independently integers from 0 to 4.

[0110] For example, c1 can be 3 or 4, preferably 4, and c2 and c3 can be 0.

[0111] That is, the fourth compound 334, which serves as an auxiliary host for the second light-emitting layer 330, and the seventh compound 364, which serves as an auxiliary host for the third light-emitting layer 360, have the same chemical structure and may be the same or different.

[0112] For example, Equation 5-1 can be represented by Equation 5-3.

[0113] [Equation 5-3]

[0114]

[0115] In Equation 5-3, Y is represented by Equation 5-2, and the definition of c1 is the same as in Equation 5-1.

[0116] Alternatively, Equation 5-1 can be represented by Equation 5-4.

[0117] [Equation 5-4]

[0118]

[0119] In Equation 5-4, Y is represented by Equation 5-2, and c4 is an integer from 0 to 3. For example, c4 can be 3, and the two cyano groups (CN) can be connected at the ortho or meta position.

[0120] As shown in Formula 5-4, two cyano groups in the fourth compound 334, which serves as an auxiliary host for the second light-emitting layer 330, and the seventh compound 364, which serves as an auxiliary host for the third light-emitting layer 360, are connected to the phenylene nucleus at the ortho or meta position. When the two cyano groups are located at the meta position rather than the ortho position, the characteristics (performance) of OLED D1 can be further improved.

[0121] For example, each of the fourth compound 334, which serves as an auxiliary host for the second light-emitting layer 330, and the seventh compound 364, which serves as an auxiliary host for the third light-emitting layer 360, may be one of the compounds in Formula 6.

[0122] [Formula 6]

[0123]

[0124]

[0125] Each of the fifth compound 336, which serves as the first fluorescent dopant of the second luminescent layer 330, and the eighth compound 366, which serves as the second fluorescent dopant of the third luminescent layer 360, is represented by Formula 7.

[0126] [Formula 7]

[0127]

[0128] In Formula 7, R31, R32, R33, R34, R35, R36 and R37 are each independently selected from the group consisting of hydrogen, substituted or unsubstituted C1-C10 alkyl groups and substituted or unsubstituted C6-C30 aryl groups, and at least one of R31, R32, R33 and R34 is a substituted or unsubstituted C1-C10 alkyl group.

[0129] For example, two or four of R31, R32, R33, and R34 may be C1-C10 alkyl groups, such as methyl. Furthermore, R35 and R36 may each be independently selected from the group consisting of hydrogen and C1-C10 alkyl groups (e.g., ethyl), and R37 may be selected from the group consisting of unsubstituted C6-C30 aryl groups (e.g., phenyl), C6-C30 aryl groups substituted with C1-C10 alkyl groups (e.g., methyl) (e.g., tert-butylphenyl), and substituted or unsubstituted C5-C30 heteroaryl groups (e.g., dibenzofuranyl).

[0130] That is, the fifth compound 336, which is the first fluorescent dopant of the second light-emitting layer 330, and the eighth compound 366, which is the second fluorescent dopant of the third light-emitting layer 360, have the same chemical structure and may be the same or different.

[0131] Each of the fifth compound 336, which serves as the first fluorescent dopant of the second luminescent layer 330, and the eighth compound 366, which serves as the second fluorescent dopant of the third luminescent layer 360, may be one of the compounds in Formula 8.

[0132] [Formula 8]

[0133]

[0134] In the first light-emitting layer 320, the weight percentage of the first compound 322 is greater than the weight percentage of the second compound 324. For example, in the first light-emitting layer 320, the second compound 324 may have a weight percentage of 1-20 relative to the first compound 322.

[0135] In the second light-emitting layer 330, the weight percentage of each of the third and fourth compounds 332 and 334 is greater than the weight percentage of the fifth compound 336, and the weight percentage of the third compound 332 may be equal to or greater than the weight percentage of the fourth compound 334. For example, in the second light-emitting layer 330, the fourth compound 334 may have 60-80% of the weight relative to the third compound 332, and the fifth compound 336 may have 0.1-10% of the weight relative to the third compound 332.

[0136] In the third light-emitting layer 360, the weight percentage of each of the sixth and seventh compounds 362 and 364 is greater than the weight percentage of the eighth compound 366, and the weight percentage of the sixth compound 362 may be equal to or greater than the weight percentage of the seventh compound 364. For example, in the third light-emitting layer 360, the seventh compound 364 may have a weight percentage of 60-80% relative to the sixth compound 362, and the eighth compound 366 may have a weight percentage of 0.1-10% relative to the sixth compound 362.

[0137] In the fourth light-emitting layer 370, the weight percentage of the ninth compound 372 is greater than that of the tenth compound 374. For example, in the fourth light-emitting layer 370, the tenth compound 374 may have a weight percentage of 1-20 relative to the ninth compound 372.

[0138] Each of the first to fourth light-emitting layers 320, 330, 360, and 370 may have a thickness of approximately 10-25 nm. The first to fourth light-emitting layers 320, 330, 360, and 370 may have the same thickness or different thicknesses.

[0139] In the second luminescent layer 330, the difference between the lowest unoccupied molecular orbital (LUMO) energy level of the fifth compound 336 "FD" as the first fluorescent dopant and the LUMO energy level of the fourth compound 334 "TD" as the auxiliary host can be -0.6 eV or greater. Furthermore, the difference between the LUMO energy level of the fifth compound 336 "FD" as the first fluorescent dopant and the LUMO energy level of the fourth compound 334 "TD" as the auxiliary host can be 0.1 eV or less. For example, the difference between the lowest unoccupied molecular orbital (LUMO) energy level of the fifth compound 336 "FD" as the first fluorescent dopant and the LUMO energy level of the fourth compound 334 "TD" as the auxiliary host can be -0.6 eV or greater and 0.1 eV or less (i.e., 0.1 eV ≥ LUMO(FD) - LUMO(TD) ≥ -0.6 eV).

[0140] In the third luminescent layer 360, the difference between the LUMO energy level of the eighth compound 366 "FD" as the second fluorescent dopant and the LUMO energy level of the seventh compound 364 "TD" as the auxiliary host can be -0.6 eV or greater. Furthermore, the difference between the LUMO energy level of the eighth compound 366 "FD" as the second fluorescent dopant and the LUMO energy level of the seventh compound 364 "TD" as the auxiliary host can be 0.1 eV or less. For example, the difference between the LUMO energy level of the eighth compound 366 "FD" as the second fluorescent dopant and the LUMO energy level of the seventh compound 364 "TD" as the auxiliary host can be -0.6 eV or greater and 0.1 eV or less (i.e., 0.1 eV ≥ LUMO(FD) - LUMO(TD) ≥ -0.6 eV). Various methods for determining HOMO energy levels are known to those skilled in the art. For example, HOMO energy levels can be determined using a conventional surface analyzer, such as the AC3 surface analyzer manufactured by RKI Instruments. This surface analyzer can be used to determine the thickness of a 50 nm thick monolayer thin film (a neat thin film). The LUMO level can be calculated as follows: LUMO = HOMO - band gap. The band gap can be calculated using any conventional method known to those skilled in the art, such as from UV-Vis measurements of a 50 nm thick monolayer thin film. For example, it can be done using an SCINCO S-3100 spectrophotometer. The HOMO and LUMO values ​​of the compounds of the examples and embodiments disclosed herein can be determined in this way. That is, the HOMO and LUMO values ​​can be values ​​determined experimentally or empirically for the thin film (e.g., a 50 nm film).

[0141] Therefore, it is possible to prevent the generation of excitocomplexes in each of the second and third light-emitting layers 330 and 360, and to improve the luminous efficiency of each of the second and third light-emitting layers 330 and 360.

[0142] The difference between the maximum emission wavelength of the first light-emitting layer 320 and the maximum emission wavelength of the second light-emitting layer 330 is 20 nm or less, and the difference between the maximum emission wavelength of the third light-emitting layer 360 and the maximum emission wavelength of the fourth light-emitting layer 370 is 20 nm or less. Specifically, the difference between the maximum emission wavelength of the second compound 324 in the first light-emitting layer 320 and the maximum emission wavelength of the fifth compound 336 in the second light-emitting layer 330 is 20 nm or less, and the difference between the maximum emission wavelength of the eighth compound 366 in the third light-emitting layer 360 and the tenth compound 374 in the fourth light-emitting layer 370 is 20 nm or less. For example, each of the first to fourth light-emitting layers 320, 330, 360, and 370 can have an emission wavelength range of 510-540 nm.

[0143] Furthermore, the difference between the average emission wavelength of the first light-emitting portion 310, which includes the first and second light-emitting layers 320 and 330, and the average emission wavelength of the second light-emitting portion 350, which includes the third and fourth light-emitting layers 360 and 370, can be 20 nm or less.

[0144] The first light-emitting part 310 may further include at least one of a first HTL 313 located below the first EML 340 and a first ETL 319 located on the first EML 340.

[0145] In addition, the first light-emitting part 310 may also include a HIL located below the first HTL 313.

[0146] In addition, the first light-emitting part 310 may also include at least one of a first EBL 315 located between the first EML 340 and the first HTL 313 and a first HBL 317 located between the first EML 340 and the first ETL 319.

[0147] The second light-emitting part 350 may further include at least one of a second HTL 351 located below the second EML 380 and a second ETL 357 located on the second EML 380.

[0148] In addition, the second light-emitting part 350 may also include an EIL located on the second ETL 357.

[0149] In addition, the second light-emitting part 350 may also include at least one of a second EBL 353 located between the second EML 380 and the second HTL 351 and a second HBL 355 located between the second EML 380 and the second ETL 357.

[0150] The CGL 390 is located between the first and second light-emitting portions 310 and 350, and the first and second light-emitting portions 310 and 350 are connected by the CGL 390. The first light-emitting portion 310, the CGL 390, and the second light-emitting portion 350 are stacked sequentially on the first electrode 210. That is, the first light-emitting portion 310 is located between the first electrode 210 and the CGL 390, and the second light-emitting portion 350 is located between the second electrode 230 and the CGL 390.

[0151] The CGL 390 can be a PN-connected CGL of N-type CGL 392 and P-type CGL 394.

[0152] The N-type CGL 392 is located between the first ETL 319 and the second HTL 351, and the P-type CGL 394 is located between the N-type CGL 392 and the second HTL 351. The N-type CGL 392 provides electrons to the first EML 340 of the first light-emitting part 310, and the P-type CGL 394 provides holes to the second EML 380 of the second light-emitting part 350.

[0153] For example, HIL 311 may include 4,4′4″-tris(3-methylphenylamino)triphenylamine (MTDATA), 4,4′,4″-tris(N,N-diphenyl-amino)triphenylamine (NATA), 4,4′,4″-tris(N-(naphthyl-1-yl)-N-phenyl-amino)triphenylamine (1T-NATA), 4,4′,4″-tris(N-(naphthyl-2-yl)-N-phenyl-amino)triphenylamine (2T-NATA), copper phthalocyanine (CuPc), tris(4-carbazole-9-yl-phenyl)amine (TCTA), N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-biphenyl-4, At least one compound from the group consisting of 4”-diamine (NPB or NPD), 1,4,5,8,9,11-hexaazatriphenylhexacarbonitrile (dipyrazine[2,3-f:2′3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile; HAT-CN), 1,3,5-tris[4-(diphenylamino)phenyl]benzene (TDAPB), poly(3,4-ethylenedioxythiophene)polystyrene sulfonate (PEDOT / PSS), and N-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluorene-2-amine. The HIL 311 may have a thickness of 1-10 nm.

[0154] Each of the first and second HTLs 313 and 351 may include a selection from N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine (TPD), NPB (NPD), 4,4′-bis(carbazole-9-yl)biphenyl (CBP), poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)-benzidine] (poly-TPD), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)] (TFB). At least one compound from the group consisting of bis-[4-(N,N-di-p-tolyl-amino)-phenyl]cyclohexane (TAPC), 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. Each of the first and second HTLs 311 and 351 may have a thickness of 20-30 nm. The first and second HTLs 311 and 351 may have the same thickness or different thicknesses.

[0155] Each of the first and second ETLs 319 and 357 may include a selection from tri-(8-hydroxyquinoline aluminum (Alq3), 2-biphenyl-4-yl-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD), spiro-PBD, lithium quinoline (Liq), 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBi), bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1′-biphenyl-4-hydroxy)aluminum (BAlq), 4,7-diphenyl-1,10-phenanthroline (Bphen), 2,9-di(naphthyl-2-yl)4,7-diphenyl-1,10-phenanthroline (NBphen), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 3-(4-biphenyl)-4 At least one compound from the group consisting of 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)phenyl]phosphine oxide (TSPO1). Each of the first and second ETLs 319 and 357 can have a thickness of 10-40 nm. For example, the thickness of the first ETL 319 can be less than the thickness of the second ETL 357.

[0156] The EIL 359 may include at least one of an alkali metal halide compound (e.g., LiF, CsF, NaF, or BaF2) and an organometallic compound (e.g., Liq, lithium benzoate, or sodium stearate). The EIL 359 may have a thickness of 1-10 nm.

[0157] Each of the first and second EBLs 315 and 353 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. Each of the first and second EBLs 315 and 353 can have a thickness of 5-15 nm.

[0158] Each of the first and second HBLs 317 and 355 may comprise at least one compound selected from the group consisting of BCP, BAlq, Alq3, PBD, spiro-PBD, Liq, di-4,6-(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′-bicarbazole and TSPO1. Each of the first and second HBLs 317 and 355 may have a thickness of 5-15 nm.

[0159] The N-type CGL 392 may include a body, which may be an anthracene derivative or the material of ETL 319 and 357, and a Li dopant. For example, the dopant, namely Li, may have 0.5% by weight in the N-type CGL 392. The P-type CGL 394 may include the material of HIL 311.

[0160] Each of the N-type CGL 392 and the P-type CGL 394 can have a thickness of 5-20 nm. Furthermore, the thickness of the N-type CGL 392 can be greater than the thickness of the P-type CGL 394.

[0161] The capping layer 290 is located on the second electrode 230. For example, the capping layer 290 may include the materials of HTL313 and 351 and may have a thickness of 50-200 nm.

[0162] The OLED D1 includes a first light-emitting portion 310 and a second light-emitting portion 350, and each of the first and second light-emitting portions 310 and 350 includes a phosphorescent light-emitting layer and a fluorescent light-emitting layer. Therefore, the OLED D1 has advantages in luminous efficiency, FWHM (color purity), and lifetime.

[0163] Figure 4 This is a schematic cross-sectional view of an OLED according to the third embodiment of this disclosure.

[0164] like Figure 4 As shown, the OLED D2 includes a first electrode 210 as a reflective electrode, a second electrode 230 as a transparent electrode (or semi-transparent electrode) facing the first electrode 210, and an organic light-emitting layer 220 between the two. The organic light-emitting layer 220 includes a first light-emitting portion 410 and a second light-emitting portion 450, wherein the first light-emitting portion includes a first EML 440 comprising the first light-emitting layer 420 and the second light-emitting layer 430, and the second light-emitting portion 450 includes a second EML 480 comprising a third light-emitting layer 460 and a fourth light-emitting layer 470. Furthermore, the organic light-emitting layer 220 may also include a CGL 490 located between the first and second light-emitting portions 410 and 450. Additionally, the OLED D1 may also include a capping layer 290 for enhancing (improving) luminous efficiency.

[0165] The organic light-emitting display device may include a red pixel region, a green pixel region, and a blue pixel region, and the OLED D1 is located in the green pixel region.

[0166] The first electrode 210 can be an anode, and the second electrode 230 can be a cathode. The first electrode 210 is a reflective electrode, and the second electrode 230 is a transparent electrode (or a semi-transparent electrode). For example, the first electrode 210 can have an ITO / Ag / ITO structure, and the second electrode 230 can be formed of MgAg.

[0167] In the first light-emitting portion 410, the first light-emitting layer 420 is located between the first electrode 210 and the second light-emitting layer 430. That is, the first light-emitting layer 410 is located closer to the first electrode 210, and the second light-emitting layer 420 is located closer to the second electrode 230. The first light-emitting layer 420 is a fluorescent light-emitting layer, and the second light-emitting layer 430 is a phosphorescent light-emitting layer.

[0168] In the second light-emitting portion 450, the fourth light-emitting layer 470 is located between the second electrode 230 and the third light-emitting layer 460. That is, the third light-emitting layer 460 is located closer to the first electrode 210, and the fourth light-emitting layer 470 is located closer to the second electrode 230. The third light-emitting layer 460 is a phosphorescent light-emitting layer, and the fourth light-emitting layer 470 is a fluorescent light-emitting layer. Specifically, in the first light-emitting portion 410, the second light-emitting layer 430, which is a phosphorescent light-emitting layer, is located closer to the second electrode 230, which is a transparent electrode (or a semi-transparent electrode), while in the second light-emitting portion 450, the fourth light-emitting layer, which is a fluorescent layer, is located closer to the second electrode 230, which is a transparent electrode.

[0169] The first luminescent layer 420 includes a third compound 422 as a second host, a fourth compound 424 as an auxiliary host (or auxiliary dopant), and a fifth compound 426 as a first fluorescent dopant (or first phosphorescent emitter). The second luminescent layer 430 includes a first compound 432 as a first host and a second compound 434 as a first phosphorescent dopant (or first phosphorescent emitter). The fourth compound 424 is a delayed fluorescence compound.

[0170] The third luminescent layer 460 includes a ninth compound 462 as the fourth host and a tenth compound 464 as the second phosphorescent dopant. The fourth luminescent layer 470 includes a sixth compound 472 as the third host, a seventh compound 474 as an auxiliary host, and an eighth compound 476 as the second fluorescent dopant. The seventh compound 474 is a delayed fluorescence compound.

[0171] Each of the first compound 432, which is the main body of the second light-emitting layer 430, the third compound 422, which is the main body of the first light-emitting layer 420, the sixth compound 472, which is the main body of the fourth light-emitting layer 470, and the ninth compound 462, which is the main body of the third light-emitting layer 460, is represented by Formula 1-1.

[0172] That is, the first compound 432, which is the main body of the second light-emitting layer 430, the third compound 422, which is the main body of the first light-emitting layer 420, the sixth compound 472, which is the main body of the fourth light-emitting layer 470, and the ninth compound 462, which is the main body of the third light-emitting layer 460, have the same chemical structure and may be the same or different.

[0173] For example, each of the following compounds—a first compound 432 as the main body of the second light-emitting layer 430, a third compound 422 as the main body of the first light-emitting layer 420, a sixth compound 472 as the main body of the fourth light-emitting layer 470, and a ninth compound 462 as the main body of the third light-emitting layer 460—can be represented by one of formulas 1-2, 1-3, and 1-4. Each of the following compounds—a first compound 432 as the main body of the second light-emitting layer 430, a third compound 422 as the main body of the first light-emitting layer 420, a sixth compound 472 as the main body of the fourth light-emitting layer 470, and a ninth compound 462 as the main body of the third light-emitting layer 460—can be selected from compounds of formula 2.

[0174] Each of the second compound 343, which serves as the first phosphorescent dopant of the second luminescent layer 430, and the tenth compound 436, which serves as the second phosphorescent dopant of the third luminescent layer 460, can be an iridium compound represented by Formula 3.

[0175] That is, the second compound 343, which is the first phosphorescent dopant of the second light-emitting layer 430, and the tenth compound 436, which is the second phosphorescent dopant of the third light-emitting layer 460, have the same chemical structure and may be the same or different.

[0176] For example, each of the second compound 434, which is the first phosphorescent dopant of the second light-emitting layer 430, and the tenth compound 464, which is the second phosphorescent dopant of the third light-emitting layer 460, can be selected from compounds of Formula 4.

[0177] Each of the fourth compound 424, which serves as an auxiliary host for the first light-emitting layer 420, and the seventh compound 474, which serves as an auxiliary host for the fourth light-emitting layer 470, can be represented by Equation 5-1.

[0178] That is, the fourth compound 424, which serves as an auxiliary host for the first light-emitting layer 420, and the seventh compound 474, which serves as an auxiliary host for the fourth light-emitting layer 470, have the same chemical structure and may be the same or different.

[0179] For example, each of the fourth compound 424, which serves as an auxiliary host for the first light-emitting layer 420, and the seventh compound 474, which serves as an auxiliary host for the fourth light-emitting layer 470, can be represented by one of Formulas 5-3 and 5-4. Each of the fourth compound 424, which serves as an auxiliary host for the first light-emitting layer 420, and the seventh compound 474, which serves as an auxiliary host for the fourth light-emitting layer 470, can be selected from compounds in Formula 6.

[0180] Each of the fifth compound 426, which serves as the first fluorescent dopant of the first luminescent layer 420, and the eighth compound 476, which serves as the second fluorescent dopant of the fourth luminescent layer 470, can be represented by Formula 7.

[0181] That is, the fifth compound 426, which is the first fluorescent dopant of the first light-emitting layer 420, and the eighth compound 476, which is the second fluorescent dopant of the fourth light-emitting layer 470, have the same chemical structure and may be the same or different.

[0182] For example, each of the fifth compound 426, which is the first fluorescent dopant of the first light-emitting layer 420, and the eighth compound 476, which is the second fluorescent dopant of the fourth light-emitting layer 470, can be selected from compounds of Formula 8.

[0183] In the first light-emitting layer 420, the weight percentage of each of the third and fourth compounds 422 and 424 is greater than the weight percentage of the fifth compound 426, and the weight percentage of the third compound 422 may be equal to or greater than the weight percentage of the fourth compound 424. For example, in the first light-emitting layer 420, the fourth compound 424 may have 60-80% of the weight relative to the third compound 422, and the fifth compound 426 may have 0.1-10% of the weight relative to the third compound 422.

[0184] In the second light-emitting layer 430, the weight percentage of the first compound 432 is greater than the weight percentage of the second compound 434. For example, in the second light-emitting layer 430, the second compound 434 may have a weight percentage of 1-20 relative to the first compound 432.

[0185] In the third light-emitting layer 460, the weight percentage of the ninth compound 462 is greater than that of the tenth compound 464. For example, in the third light-emitting layer 460, the tenth compound 464 may have a weight percentage of 1-20 relative to the ninth compound 462.

[0186] In the fourth light-emitting layer 470, the weight percentage of each of the sixth compound 472 and the seventh compound 474 is greater than the weight percentage of the eighth compound 476, and the weight percentage of the sixth compound 472 may be equal to or greater than the weight percentage of the seventh compound 474. For example, in the fourth light-emitting layer 470, the seventh compound 474 may have 60-80% of the weight relative to the sixth compound 472, and the eighth compound 476 may have 0.1-10% of the weight relative to the sixth compound 472.

[0187] Each of the first to fourth light-emitting layers 420, 430, 460, and 470 may have a thickness of approximately 10-25 nm. The first to fourth light-emitting layers 420, 430, 460, and 470 may have the same thickness or different thicknesses.

[0188] In the first light-emitting layer 420, the difference between the LUMO energy level of the fifth compound 426 "FD" as the first fluorescent dopant and the LUMO energy level of the fourth compound 424 "TD" as the auxiliary host can be -0.6 eV or greater and 0.1 eV or less (i.e., 0.1 eV ≥ LUMO(FD) - LUMO(TD) ≥ -0.6 eV).

[0189] In the fourth light-emitting layer 470, the difference between the LUMO energy level of the eighth compound 476 "FD" as the second fluorescent dopant and the LUMO energy level of the seventh compound 474 "TD" as the auxiliary host can be -0.6 eV or greater and 0.1 eV or less (i.e., 0.1 eV ≥ LUMO(FD) - LUMO(TD) ≥ -0.6 eV).

[0190] Therefore, the generation of excitocomplexes in each of the first and fourth light-emitting layers 420 and 470 can be prevented, and the luminous efficiency of each of the first and fourth light-emitting layers 420 and 470 can be improved.

[0191] The difference between the maximum emission wavelength of the first light-emitting layer 420 and the maximum emission wavelength of the second light-emitting layer 430 is 20 nm or less, and the difference between the maximum emission wavelength of the third light-emitting layer 460 and the maximum emission wavelength of the fourth light-emitting layer 470 is 20 nm or less. Specifically, the difference between the maximum emission wavelength of the second compound 434 in the second light-emitting layer 430 and the maximum emission wavelength of the fifth compound 426 in the first light-emitting layer 420 is 20 nm or less, and the difference between the maximum emission wavelength of the eighth compound 476 in the fourth light-emitting layer 470 and the maximum emission wavelength of the tenth compound 464 in the third light-emitting layer 460 is 20 nm or less. For example, each of the first to fourth light-emitting layers 420, 430, 460, and 470 can have an emission wavelength range of 510-540 nm.

[0192] Furthermore, the difference between the average emission wavelength of the first light-emitting portion 410, which includes the first and second light-emitting layers 420 and 430, and the average emission wavelength of the second light-emitting portion 450, which includes the third and fourth light-emitting layers 460 and 470, can be 20 nm or less.

[0193] The first light-emitting part 410 may further include at least one of a first HTL 413 located below the first EML 440 and a first ETL 419 located on the first EML 440.

[0194] In addition, the first light-emitting part 410 may also include a HIL located below the first HTL 413.

[0195] In addition, the first light-emitting part 410 may also include at least one of a first EBL 415 located between the first EML 440 and the first HTL 413 and a first HBL 417 located between the first EML 440 and the first ETL 419.

[0196] The second light-emitting part 450 may further include at least one of a second HTL 451 located below the second EML 480 and a second ETL 457 located on the second EML 480.

[0197] In addition, the second light-emitting part 450 may also include an EIL located on the second ETL 457.

[0198] In addition, the second light-emitting part 450 may also include at least one of a second EBL 453 located between the second EML 480 and the second HTL 451 and a second HBL 455 located between the second EML 480 and the second ETL 457.

[0199] The CGL 490 is located between the first and second light-emitting portions 410 and 450, and the first and second light-emitting portions 410 and 450 are connected by the CGL 490. The first light-emitting portion 410, the CGL 490, and the second light-emitting portion 450 are stacked sequentially on the first electrode 210. That is, the first light-emitting portion 410 is located between the first electrode 210 and the CGL 490, and the second light-emitting portion 450 is located between the second electrode 230 and the CGL 490.

[0200] The CGL 490 can be a PN-connected CGL of N-type CGL 492 and P-type CGL 494.

[0201] The N-type CGL 492 is located between the first ETL 419 and the second HTL 451, and the P-type CGL 494 is located between the N-type CGL 492 and the second HTL 451. The N-type CGL 492 provides electrons to the first EML 440 of the first light-emitting part 410, and the P-type CGL 494 provides holes to the second EML 480 of the second light-emitting part 450.

[0202] The capping layer 290 is located on the second electrode 230. For example, the capping layer 290 may include the materials of HTL413 and 451 and may have a thickness of 50-200 nm.

[0203] The OLED D2 includes a first light-emitting portion 410 and a second light-emitting portion 450, and each of the first and second light-emitting portions 410 and 450 includes a phosphorescent light-emitting layer and a fluorescent light-emitting layer. Therefore, the OLED D2 has advantages in luminous efficiency, FWHM (color purity), and lifetime.

[0204] Figure 5 This is a schematic cross-sectional view of an OLED according to the fourth embodiment of this disclosure.

[0205] like Figure 5 As shown, the OLED D3 includes a first electrode 210 as a reflective electrode, a second electrode 230 as a transparent electrode (or semi-transparent electrode) facing the first electrode 210, and an organic light-emitting layer 220 between the two. The organic light-emitting layer 220 includes a first light-emitting portion 510 and a second light-emitting portion 550, wherein the first light-emitting portion 510 includes a first EML 540 comprising the first light-emitting layer 520 and the second light-emitting layer 530, and the second light-emitting portion 550 includes a second EML 580 comprising a third light-emitting layer 560 and a fourth light-emitting layer 570. Furthermore, the organic light-emitting layer 220 may also include a CGL 590 located between the first and second light-emitting portions 510 and 550. Additionally, the OLED D1 may also include a capping layer 290 for enhancing (improving) luminous efficiency.

[0206] The organic light-emitting display device may include a red pixel region, a green pixel region, and a blue pixel region, and the OLED D1 is located in the green pixel region.

[0207] The first electrode 210 can be an anode, and the second electrode 230 can be a cathode. The first electrode 210 is a reflective electrode, and the second electrode 230 is a transparent electrode (or a semi-transparent electrode). For example, the first electrode 210 can have an ITO / Ag / ITO structure, and the second electrode 230 can be formed of MgAg.

[0208] In the first light-emitting portion 510, the first light-emitting layer 520 is located between the first electrode 210 and the second light-emitting layer 530. That is, the first light-emitting layer 510 is located closer to the first electrode 210, while the second light-emitting layer 520 is located closer to the second electrode 230. The first light-emitting layer 520 is a phosphorescent light-emitting layer, and the second light-emitting layer 530 is a fluorescent light-emitting layer.

[0209] In the second light-emitting portion 550, the fourth light-emitting layer 570 is located between the second electrode 230 and the third light-emitting layer 560. That is, the third light-emitting layer 560 is located closer to the first electrode 210, while the fourth light-emitting layer 570 is located closer to the second electrode 230. The third light-emitting layer 560 is a phosphorescent light-emitting layer, and the fourth light-emitting layer 570 is a fluorescent light-emitting layer. Specifically, in the first light-emitting portion 510, the second light-emitting layer 530, which is a fluorescent light-emitting layer, is located closer to the second electrode 230, which is a transparent electrode (or a semi-transparent electrode), while in the second light-emitting portion 550, the fourth light-emitting layer, which is a fluorescent layer, is located closer to the second electrode 230, which is a transparent electrode.

[0210] The first luminescent layer 520 includes a first compound 522 as a first host and a second compound 524 as a first phosphorescent dopant (or first phosphorescent emitter). The second luminescent layer 530 includes a third compound 532 as a second host, a fourth compound 534 as an auxiliary host (or auxiliary dopant), and a fifth compound 536 as a first fluorescent dopant (or first phosphor). The fourth compound 534 is a delayed fluorescence compound.

[0211] The third luminescent layer 560 includes a ninth compound 562 as the fourth host and a tenth compound 564 as the second phosphorescent dopant. The fourth luminescent layer 570 includes a sixth compound 572 as the third host, a seventh compound 574 as an auxiliary host, and an eighth compound 576 as the second fluorescent dopant. The seventh compound 574 is a delayed fluorescence compound.

[0212] Each of the first compound 522, which is the main body of the first light-emitting layer 520, the third compound 532, which is the main body of the second light-emitting layer 530, the sixth compound 572, which is the main body of the fourth light-emitting layer 570, and the ninth compound 562, which is the main body of the third light-emitting layer 560, is represented by Formula 1-1.

[0213] That is, the first compound 522, which is the main body of the first light-emitting layer 520, the third compound 532, which is the main body of the second light-emitting layer 530, the sixth compound 572, which is the main body of the fourth light-emitting layer 570, and the ninth compound 562, which is the main body of the third light-emitting layer 560, have the same chemical structure and may be the same or different.

[0214] For example, the first compound 522, which is the main body of the first light-emitting layer 520, the third compound 532, which is the main body of the second light-emitting layer 530, the sixth compound 572, which is the main body of the fourth light-emitting layer 570, and the ninth compound 562, which is the main body of the third light-emitting layer 560, can be represented by one of formulas 1-2, 1-3, and 1-4. Each of the first compound 522, the third compound 532, the sixth compound 572, and the ninth compound 562, which is the main body of the third light-emitting layer 560, can be selected from compounds in formula 2.

[0215] Each of the second compound 524, which serves as the first phosphorescent dopant of the first luminescent layer 520, and the tenth compound 564, which serves as the second phosphorescent dopant of the third luminescent layer 560, can be an iridium compound represented by Formula 3.

[0216] That is, the second compound 524, which is the first phosphorescent dopant of the first light-emitting layer 520, and the tenth compound 564, which is the second phosphorescent dopant of the third light-emitting layer 560, have the same chemical structure and may be the same or different.

[0217] For example, each of the second compound 524, which is the first phosphorescent dopant of the first light-emitting layer 520, and the tenth compound 564, which is the second phosphorescent dopant of the third light-emitting layer 560, can be selected from compounds of Formula 4.

[0218] Each of the fourth compound 534, which serves as an auxiliary host for the second light-emitting layer 530, and the seventh compound 574, which serves as an auxiliary host for the fourth light-emitting layer 570, can be represented by Formula 5-1.

[0219] That is, the fourth compound 534, which serves as an auxiliary host for the second light-emitting layer 530, and the seventh compound 574, which serves as an auxiliary host for the fourth light-emitting layer 570, have the same chemical structure and may be the same or different.

[0220] For example, each of the fourth compound 534, which serves as an auxiliary host for the second light-emitting layer 530, and the seventh compound 574, which serves as an auxiliary host for the fourth light-emitting layer 570, can be represented by formulas 5-3 and 5-4. Each of the fourth compound 534, which serves as an auxiliary host for the second light-emitting layer 530, and the seventh compound 574, which serves as an auxiliary host for the fourth light-emitting layer 570, can be selected from compounds in formula 6.

[0221] Each of the fifth compound 536, which serves as the first fluorescent dopant of the second luminescent layer 530, and the eighth compound 576, which serves as the second fluorescent dopant of the fourth luminescent layer 570, can be represented by Formula 7.

[0222] That is, the fifth compound 536, which is the first fluorescent dopant of the second light-emitting layer 530, and the eighth compound 576, which is the second fluorescent dopant of the fourth light-emitting layer 570, have the same chemical structure and may be the same or different.

[0223] For example, each of the fifth compound 536, which is the first fluorescent dopant of the second light-emitting layer 530, and the eighth compound 576, which is the second fluorescent dopant of the fourth light-emitting layer 570, can be selected from compounds of Formula 8.

[0224] In the first light-emitting layer 520, the weight percentage of the first compound 522 is greater than the weight percentage of the second compound 524. For example, in the first light-emitting layer 520, the second compound 524 may have a weight percentage of 1-20 relative to the first compound 522.

[0225] In the second light-emitting layer 530, the weight percentage of each of the third and fourth compounds 532 and 534 is greater than the weight percentage of the fifth compound 536, and the weight percentage of the third compound 532 may be equal to or greater than the weight percentage of the fourth compound 534. For example, in the second light-emitting layer 530, the fourth compound 534 may have 60-80% of the weight relative to the third compound 532, and the fifth compound 536 may have 0.1-10% of the weight relative to the third compound 532.

[0226] In the third light-emitting layer 560, the weight percentage of the ninth compound 562 is greater than that of the tenth compound 564. For example, in the third light-emitting layer 560, the tenth compound 564 may have a weight percentage of 1-20 relative to the ninth compound 562.

[0227] In the fourth light-emitting layer 570, the weight percentage of each of the sixth compound 572 and the seventh compound 574 is greater than the weight percentage of the eighth compound 576, and the weight percentage of the sixth compound 572 may be equal to or greater than the weight percentage of the seventh compound 574. For example, in the fourth light-emitting layer 570, the seventh compound 574 may have 60-80% of the weight relative to the sixth compound 572, and the eighth compound 576 may have 0.1-10% of the weight relative to the sixth compound 572.

[0228] Each of the first to fourth light-emitting layers 520, 530, 560 and 570 may have a thickness of approximately 10-25 nm. The first to fourth light-emitting layers 520, 530, 560 and 570 may have the same thickness or different thicknesses.

[0229] In the second luminescent layer 530, the difference between the LUMO energy level of the fifth compound 536 "FD" as the first fluorescent dopant and the LUMO energy level of the fourth compound 534 "TD" as the auxiliary host can be -0.6 eV or greater and 0.1 eV or less (i.e., 0.1 eV ≥ LUMO(FD) - LUMO(TD) ≥ -0.6 eV). In the fourth luminescent layer 570, the difference between the LUMO energy level of the eighth compound 576 "FD" as the second fluorescent dopant and the LUMO energy level of the seventh compound 574 "TD" as the auxiliary host can be -0.6 eV or greater and 0.1 eV or less (i.e., 0.1 eV ≥ LUMO(FD) - LUMO(TD) ≥ -0.6 eV). Therefore, the formation of exciton complexes in each of the second and fourth luminescent layers 530 and 570 can be prevented, and the luminous efficiency of each of the second and fourth luminescent layers 530 and 570 can be improved.

[0230] The difference between the maximum emission wavelength of the first light-emitting layer 520 and the maximum emission wavelength of the second light-emitting layer 530 is 20 nm or less, and the difference between the maximum emission wavelength of the third light-emitting layer 560 and the maximum emission wavelength of the fourth light-emitting layer 570 is 20 nm or less. Specifically, the difference between the maximum emission wavelength of the fifth compound 536 in the second light-emitting layer 530 and the maximum emission wavelength of the second compound 524 in the first light-emitting layer 520 is 20 nm or less, and the difference between the maximum emission wavelength of the eighth compound 576 in the fourth light-emitting layer 570 and the maximum emission wavelength of the tenth compound 564 in the third light-emitting layer 560 is 20 nm or less. For example, each of the first to fourth light-emitting layers 520, 530, 560, and 570 can have an emission wavelength range of 510-540 nm.

[0231] Furthermore, the difference between the average emission wavelength of the first light-emitting portion 510, which includes the first and second light-emitting layers 520 and 530, and the average emission wavelength of the second light-emitting portion 550, which includes the third and fourth light-emitting layers 560 and 570, can be 20 nm or less.

[0232] In the first EML 540, the intensity of the second emission peak of the second light-emitting layer 530, which is closer to the second electrode 230 (which serves as a transparent electrode) than the first light-emitting layer 520, is equal to or less than the intensity of the second emission peak of the first light-emitting layer 520. That is, in the first EML 540, the intensity of the second emission peak of the fifth compound 536, which serves as a light emitter in the second light-emitting layer 530, is equal to or less than the intensity of the second emission peak of the second compound 524, which serves as a light emitter in the first light-emitting layer 520. Preferably, in the first EML 540, the intensity of the second emission peak of the second light-emitting layer 530 is less than the intensity of the second emission peak of the first light-emitting layer 520. It is understood that the emission peaks of the layers and compounds in their respective layers described in the embodiments and examples herein can be emission peaks of a photoluminescence spectrum. Additionally or alternatively, they can be emission peaks of compounds used in a diode. The wavelength of each second emission peak is longer than the wavelength of the corresponding first emission peak.

[0233] In the second EML 580, the intensity of the second emission peak of the fourth light-emitting layer 570, which is closer to the second electrode 230 (which serves as a transparent electrode) than the third light-emitting layer 560, is equal to or less than the intensity of the second emission peak of the third light-emitting layer 560. That is, in the second EML 580, the intensity of the second emission peak of the eighth compound 576, which serves as a light emitter in the fourth light-emitting layer 570, is equal to or less than the intensity of the second emission peak of the tenth compound 564, which serves as a light emitter in the third light-emitting layer 560. Preferably, in the second EML 580, the intensity of the second emission peak of the fourth light-emitting layer 570 is less than the intensity of the second emission peak of the third light-emitting layer 560.

[0234] refer to Figures 6A to 6E The PL spectra are those of phosphorescent dopants (i.e., compounds PD1 and PD2 in Formula 4) and fluorescent dopants (i.e., compounds FD1, FD2 and FD3 in Formula 8), wherein the intensity of the second emission peak of each of compounds PD1 and PD2 (which may be the second compound 524 of the first emitting layer 520 and the tenth compound 564 of the third emitting layer 560) is greater than the intensity of the second emission peak of each of compounds FD1, FD2 and FD3 (which may be the fifth compound 536 of the second emitting layer 530 and the eighth compound 576 of the fourth emitting layer 570).

[0235] Therefore, the cavity effect in the OLED D3 is enhanced or strengthened, thereby significantly improving luminous efficiency and color purity.

[0236] In the second compound 524 of the first luminescent layer 520, the second emission peak intensity "I" 2nd"Compared with the first launch peak intensity" I 1st The ratio is 0.55 or greater and less than 1 (i.e., 0.55 ≤ (I 2n d / I 1st (<1.0). Furthermore, in the tenth compound 564 of the third luminescent layer 560, the second emission peak intensity "I 2nd "Compared with the first launch peak intensity" I 1st The ratio is 0.55 or greater and less than 1 (i.e., 0.55 ≤ (I 2n d / I 1st (<1.0). Therefore, the luminous efficiency (brightness) of the OLED D3 is significantly improved. In this case, the first emission peak, "1st peak", is the peak with the maximum emission intensity, and the second emission peak, "2nd peak", is the peak with the second largest emission intensity. The emission peak intensity can be measured using any conventional method known to those skilled in the art, such as using a fluorescence spectrometer, such as an Edinburgh Instruments / FS-5 fluorescence spectrometer. The measurement conditions for the emission peaks of the compounds described in the embodiments and examples herein are: at room temperature in toluene solution (1.0 x 10⁻⁶). -5 Photoluminescence in (M concentration).

[0237] Reference Figure 6A and 6B In compounds PD1 and PD2, which may be the second compound 524 of the first luminescent layer 520 and the tenth compound 564 of the third luminescent layer 560, the second emission peak intensity "I 2nd "and the intensity of the first emission peak" 1st The ratios were approximately 0.57 and 0.6, respectively.

[0238] The first light-emitting part 510 may further include at least one of a first HTL 513 located below the first EML 540 and a first ETL 519 located on the first EML 540.

[0239] In addition, the first light-emitting part 510 may also include a HIL 511 located below the first HTL 513.

[0240] In addition, the first light-emitting part 510 may also include at least one of a first EBL 515 located between the first EML 540 and the first HTL 513 and a first HBL 517 located between the first EML 540 and the first ETL 519.

[0241] The second light-emitting part 550 may further include at least one of a second HTL 551 located below the second EML 580 and a second ETL 557 located on the second EML 580.

[0242] In addition, the second light-emitting part 550 may also include an EIL 559 located on the second ETL 557.

[0243] In addition, the second light-emitting part 550 may also include at least one of a second EBL 553 located between the second EML 580 and the second HTL 551 and a second HBL 555 located between the second EML 580 and the second ETL 557.

[0244] The CGL 590 is located between the first and second light-emitting portions 510 and 550, and the first and second light-emitting portions 510 and 550 are connected by the CGL 590. The first light-emitting portion 510, the CGL 590, and the second light-emitting portion 550 are stacked sequentially on the first electrode 210. That is, the first light-emitting portion 510 is located between the first electrode 210 and the CGL 590, and the second light-emitting portion 550 is located between the second electrode 230 and the CGL 590.

[0245] The CGL 590 can be a PN-connected CGL of N-type CGL 592 and P-type CGL 594.

[0246] The N-type CGL 592 is located between the first ETL 519 and the second HTL 551, and the P-type CGL 594 is located between the N-type CGL 592 and the second HTL 551. The N-type CGL 592 provides electrons to the first EML 540 of the first light-emitting part 510, and the P-type CGL 594 provides holes to the second EML 580 of the second light-emitting part 550.

[0247] The capping layer 290 is located on the second electrode 230. For example, the capping layer 290 may include the materials of HTL513 and 551 and may have a thickness of 50-200 nm.

[0248] The OLED D3 includes a first light-emitting portion 510 and a second light-emitting portion 550, and each of the first and second light-emitting portions 510 and 550 includes a phosphorescent light-emitting layer and a fluorescent light-emitting layer. Therefore, the OLED D3 has advantages in luminous efficiency, FWHM (color purity), and lifetime.

[0249] Figure 7This is a schematic cross-sectional view of an organic light-emitting display device according to the fifth embodiment of this disclosure.

[0250] like Figure 7 As shown, the organic light-emitting display device 600 includes a substrate 610 defining first to third pixel regions P1, P2, and P3, and a TFT Tr and an OLED D above the substrate 610. The OLED D is disposed above and connected to the TFT Tr.

[0251] 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. The first to third pixel regions P1, P2, and P3 constitute a pixel unit. Alternatively, the pixel unit may also include a white pixel region.

[0252] The substrate 610 can be a glass substrate or a flexible substrate.

[0253] A buffer layer 612 is formed on the substrate 610, and the TFT Tr is formed on the buffer layer 612. The buffer layer 612 may be omitted.

[0254] The TFT Tr is located on the buffer layer 612. The TFT Tr includes a semiconductor layer, a gate, a source, and a drain, and serves as a driving element. That is, the TFT Tr can drive the TFT Td (…). Figure 1 ).

[0255] A planarization layer (or passivation layer) 650 is formed on the TFT Tr. The planarization layer 650 has a flat top surface and includes a drain contact hole 652 that exposes the drain of the TFT Tr.

[0256] The OLED D is disposed on the planarization layer 650 and includes a first electrode 210, an organic light-emitting layer 220, and a second electrode 230. The first electrode 210 is connected to the drain of the TFT Tr, and the organic light-emitting layer 220 and the second electrode 230 are stacked sequentially on the first electrode 240. The OLED D is disposed in each of the first to third pixel regions P1 to P3, and emits light of different colors in the first to third pixel regions P1 to P3. For example, the OLED D in the first pixel region P1 can emit green light, the OLED D in the second pixel region P2 can emit red light, and the OLED D in the third pixel region P3 can emit blue light.

[0257] The first electrode 210 is formed separately in the first to third pixel regions P1 to P3, and the second electrode 230 is formed integrally to cover the first to third pixel regions P1 to P3.

[0258] The first electrode 210 is one of the anode and the cathode, and the second electrode 230 is the other of the anode and the cathode. Furthermore, the first electrode 210 is a reflective electrode, and the second electrode 230 is a transparent electrode (or a semi-transparent electrode). That is, light from the OLED D passes through the second electrode 230 to display an image (i.e., a top-emitting organic light-emitting display device).

[0259] For example, the first electrode 210 may be an anode and may include a transparent conductive oxide material layer and a reflective layer. The transparent conductive oxide material layer may be formed of a conductive material such as transparent conductive oxide (TCO) and has a relatively high work function. That is, the first electrode 210 may be a reflective electrode.

[0260] The second electrode 230 may be a cathode and may be formed of a conductive material having a relatively low work function. The second electrode 230 may have a thin profile and be transparent (or translucent).

[0261] The organic light-emitting layer 220 may have a bonding Figures 3 to 5 The structure of the explanation.

[0262] refer to Figure 3 The organic light-emitting layer 220 includes a first light-emitting part 310 and a second light-emitting part 350, wherein the first light-emitting part 310 includes a first EML 340 comprising the first and second light-emitting layers 320 and 330, and the second light-emitting part 350 includes a second EML 380 comprising the third and fourth light-emitting layers 360 and 370.

[0263] In the first light-emitting portion 310, the first light-emitting layer 320 is located between the first electrode 210 and the second light-emitting layer 330. The first light-emitting layer 320 is a phosphorescent light-emitting layer, and the second light-emitting layer 330 is a fluorescent light-emitting layer. In the second light-emitting portion 350, the fourth light-emitting layer 370 is located between the second electrode 230 and the third light-emitting layer 360. The third light-emitting layer 360 is a fluorescent light-emitting layer, and the fourth light-emitting layer 370 is a phosphorescent light-emitting layer. That is, in the first light-emitting portion 310, the second light-emitting layer 330, which is a fluorescent light-emitting layer, is located closer to the second electrode 230, which is a transparent electrode (or a semi-transparent electrode), while in the second light-emitting portion 350, the fourth light-emitting layer, which is a phosphorescent light-emitting layer, is located closer to the second electrode 230, which is a transparent electrode.

[0264] The first luminescent layer 320 includes a first compound 322 as a first host and a second compound 324 as a first phosphorescent dopant (or first phosphorescent emitter). The second luminescent layer 330 includes a third compound 332 as a second host, a fourth compound 334 as an auxiliary host (or auxiliary dopant), and a fifth compound 336 as a first fluorescent dopant (or first fluorescent emitter). The fourth compound 334 is a delayed fluorescence compound.

[0265] The third luminescent layer 360 includes a sixth compound 362 as a third host, a seventh compound 364 as an auxiliary host, and an eighth compound 366 as a second fluorescent dopant. The seventh compound 364 is a delayed fluorescence compound. The fourth luminescent layer 370 includes a ninth compound 372 as a fourth host and a tenth compound 374 as a second phosphorescent dopant.

[0266] Each of the following compounds—the first compound 322, the third compound 332, the sixth compound 362, and the ninth compound 372—serving as the main body of the first luminescent layer 320, the second compound 330, the sixth compound 362, and the ninth compound 372—serving as the main body of the fourth luminescent layer 370, is represented by Formula 1-1. Each of the following compounds—the second compound 324, the first phosphorescent dopant of the first luminescent layer 320, and the tenth compound 374, the second phosphorescent dopant of the fourth luminescent layer 370—is an iridium compound represented by Formula 3. Each of the fourth compound 334, the fourth compound 334, the fourth compound 334, and the seventh compound 364, the seventh compound 364, the seventh compound 364, the eighth compound 366, the eighth phosphorescent dopant of the third luminescent layer 360, is represented by Formula 5-1. Each of the fifth compound 336, the fifth compound 336, the first fluorescent dopant of the second luminescent layer 330, and the eighth compound 366, the eighth fluorescent dopant of the third luminescent layer 360, is represented by Formula 7.

[0267] refer to Figure 4 The organic light-emitting layer 220 includes a first light-emitting part 410 and a second light-emitting part 450, wherein the first light-emitting part 410 includes a first EML 440 containing the first light-emitting layer 420 and the second light-emitting layer 430, and the second light-emitting part 450 includes a second EML 480 containing a third light-emitting layer 460 and a fourth light-emitting layer 470.

[0268] In the first light-emitting portion 410, the first light-emitting layer 420 is located between the first electrode 210 and the second light-emitting layer 430. The first light-emitting layer 420 is a fluorescent light-emitting layer, and the second light-emitting layer 430 is a phosphorescent light-emitting layer. In the second light-emitting portion 450, the fourth light-emitting layer 470 is located between the second electrode 230 and the third light-emitting layer 460. The third light-emitting layer 460 is a phosphorescent light-emitting layer, and the fourth light-emitting layer 470 is a fluorescent light-emitting layer. That is, in the first light-emitting portion 410, the second light-emitting layer 430, which is a phosphorescent light-emitting layer, is located closer to the second electrode 230, which is a transparent electrode (or a semi-transparent electrode), while in the second light-emitting portion 450, the fourth light-emitting layer, which is a fluorescent layer, is located closer to the second electrode 230, which is a transparent electrode.

[0269] The first luminescent layer 420 includes a third compound 422 as a second host, a fourth compound 424 as an auxiliary host (or auxiliary dopant), and a fifth compound 426 as a first fluorescent dopant (or first phosphorescent emitter). The second luminescent layer 430 includes a first compound 432 as a first host and a second compound 434 as a first phosphorescent dopant (or first phosphorescent emitter). The fourth compound 424 is a delayed fluorescence compound.

[0270] The third luminescent layer 460 includes a ninth compound 462 as the fourth host and a tenth compound 464 as the second phosphorescent dopant. The fourth luminescent layer 470 includes a sixth compound 472 as the third host, a seventh compound 474 as an auxiliary host, and an eighth compound 476 as the second fluorescent dopant. The seventh compound 474 is a delayed fluorescence compound.

[0271] Each of the following compounds—the first compound 432, the third compound 422, the sixth compound 472, and the ninth compound 462—serving as the main body of the second luminescent layer 430, the first compound 420, the sixth compound 472, and the ninth compound 462, serving as the main body of the third luminescent layer 460, is represented by Formula 1-1. Each of the following compounds—the second compound 343, the first phosphorescent dopant of the second luminescent layer 430, and the tenth compound 436, the second phosphorescent dopant of the third luminescent layer 460—can be an iridium compound represented by Formula 3. Each of the fourth compound 424, the fourth compound 424, and the seventh compound 474, the seventh compound 474, the auxiliary main body of the first luminescent layer 420, can be represented by Formula 5-1. The fifth compound 426, the first fluorescent dopant of the first luminescent layer 420, and the eighth compound 476, the second fluorescent dopant of the fourth luminescent layer 470, can be represented by Formula 7.

[0272] refer to Figure 5 The organic light-emitting layer 220 includes a first light-emitting part 510 and a second light-emitting part 550, wherein the first light-emitting part 510 includes a first EML 540 containing a first light-emitting layer 520 and a second light-emitting layer 530, and the second light-emitting part 550 includes a second EML 580 containing a third light-emitting layer 580 and a fourth light-emitting layer 570.

[0273] In the first light-emitting portion 510, the first light-emitting layer 520 is located between the first electrode 210 and the second light-emitting layer 530. The first light-emitting layer 520 is a phosphorescent light-emitting layer, and the second light-emitting layer 530 is a fluorescent light-emitting layer. In the second light-emitting portion 550, the fourth light-emitting layer 570 is located between the second electrode 230 and the third light-emitting layer 560. The third light-emitting layer 560 is a phosphorescent light-emitting layer, and the fourth light-emitting layer 570 is a fluorescent light-emitting layer. That is, in the first light-emitting portion 510, the second light-emitting layer 530, which is a fluorescent light-emitting layer, is located closer to the second electrode 230, which is a transparent electrode (or a semi-transparent electrode), and in the second light-emitting portion 550, the fourth light-emitting layer, which is a fluorescent layer, is located closer to the second electrode 230, which is a transparent electrode.

[0274] The first luminescent layer 520 includes a first compound 522 as a first host and a second compound 524 as a first phosphorescent dopant (or first phosphorescent emitter). The second luminescent layer 530 includes a third compound 532 as a second host, a fourth compound 534 as an auxiliary host (or auxiliary dopant), and a fifth compound 536 as a first fluorescent dopant (or first fluorescent emitter). The fourth compound 534 is a delayed fluorescence compound.

[0275] The third luminescent layer 560 includes a ninth compound 562 as the fourth host and a tenth compound 564 as the second phosphorescent dopant. The fourth luminescent layer 570 includes a sixth compound 572 as the third host, a seventh compound 574 as an auxiliary host, and an eighth compound 576 as the second fluorescent dopant. The seventh compound 574 is a delayed fluorescence compound.

[0276] Each of the following compounds—the first compound 522 as the main body of the first emitting layer 520, the third compound 532 as the main body of the second emitting layer 530, the sixth compound 572 as the main body of the fourth emitting layer 570, and the ninth compound 562 as the main body of the third emitting layer 560—is represented by Formula 1-1. Each of the second compound 524 as the first phosphorescent dopant of the first emitting layer 520 and the tenth compound 564 as the second phosphorescent dopant of the third emitting layer 560 can be an iridium compound represented by Formula 3. Each of the fourth compound 534 as an auxiliary main body of the second emitting layer 530 and the seventh compound 574 as an auxiliary main body of the fourth emitting layer 570 can be represented by Formula 5-1. The fifth compound 536 as the first fluorescent dopant of the second emitting layer 530 and the eighth compound 576 as the second fluorescent dopant of the fourth emitting layer 570 can be represented by Formula 7.

[0277] Although not shown, the OLED D may also include a capping layer (not shown) on the second electrode 230. The luminous efficiency of the OLED D can be further improved by the capping layer.

[0278] An encapsulation film (or encapsulation layer) 670 is formed on the second electrode 230 to prevent moisture from penetrating into the OLED D. The encapsulation film 670 may have a structure including an inorganic insulating layer and an organic insulating layer.

[0279] Although not shown, the organic light-emitting display device 600 may include color filters corresponding to the red, green, and blue pixel regions. For example, the color filters may be located on or above the OLED D or encapsulation film 670.

[0280] Furthermore, the organic light-emitting display device 600 may also include a cover window (not shown) on or above the encapsulation film 670 or the color filter. In this case, the substrate 610 and the cover window have flexible properties, thereby providing a flexible organic light-emitting display device.

[0281] Figure 8 This is a schematic cross-sectional view of an organic light-emitting display device according to the sixth embodiment of this disclosure.

[0282] like Figure 8 As shown, the organic light-emitting display device 700 includes a substrate 710 defining first to third pixel regions P1, P2, and P3, a TFT Tr, and an OLED D above the substrate 710. The OLED D is disposed above and connected to the TFT Tr.

[0283] 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. The first to third pixel regions P1, P2, and P3 constitute a pixel unit. Alternatively, the pixel unit may also include a white pixel region.

[0284] The substrate 710 can be a glass substrate or a flexible substrate.

[0285] A buffer layer 712 is formed on the substrate 710, and the TFT Tr is formed on the buffer layer 712. The buffer layer 712 may be omitted.

[0286] The TFT Tr is located on the buffer layer 712. The TFT Tr includes a semiconductor layer, a gate, a source, and a drain, and serves as a driving element. That is, the TFT Tr can drive the TFT Td (…). Figure 1 ).

[0287] A planarization layer (or passivation layer) 750 is formed on the TFT Tr. The planarization layer 750 has a flat top surface and includes a drain contact hole 752 that exposes the drain of the TFT Tr.

[0288] The OLED D is disposed on the planarization layer 750 and includes a first electrode 210, an organic light-emitting layer 220, and a second electrode 230. The first electrode 210 is connected to the drain of the TFT Tr, and the organic light-emitting layer 210 is connected to the drain of the TFT Tr. The light-emitting layer 220 and the second electrode 230 are stacked sequentially on the first electrode 240. The OLED D is disposed in each of the first to third pixel regions P1 to P3 and emits light of different colors in the first to third pixel regions P1 to P3. For example, the OLED D in the first pixel region P1 can emit green light, the OLED D in the second pixel region P2 can emit red light, and the OLED D in the third pixel region P3 can emit blue light.

[0289] The first electrode 210 is formed separately in the first to third pixel regions P1 to P3, and the second electrode 230 is formed integrally to cover the first to third pixel regions P1 to P3.

[0290] The first electrode 210 is one of the anode and the cathode, and the second electrode 230 is the other of the anode and the cathode. Furthermore, the first electrode 210 is a transparent electrode (or a semi-transparent electrode), and the second electrode 230 is a reflective electrode. That is, light from the OLED D passes through the first electrode 210 to display an image on the substrate 710. (i.e., a bottom-emitting organic light-emitting display device)

[0291] For example, the first electrode 210 may be an anode and may include a conductive material with a relatively high work function (e.g., transparent conductive oxide (TCO)) and a reflective layer.

[0292] The second electrode 230 may be a cathode and may be formed of a conductive material with a relatively low work function.

[0293] The organic light-emitting layer 220 may have a bonding Figures 3 to 5 The structure is explained, but the stacking order of the first light-emitting layers 320, 420 and 520 with the second light-emitting layers 330, 430 and 530, and the stacking order of the third light-emitting layers 360, 460 and 560 with the fourth light-emitting layers 370, 470 and 570 are changed.

[0294] For example, in Figure 5 In the OLED D3, in the first EML 540, the second light-emitting layer 530, which serves as a fluorescent light-emitting layer, is positioned closer to the first electrode 210, which serves as a transparent electrode, than the first light-emitting layer 520. In the second EML 580, the fourth light-emitting layer 570, which serves as a fluorescent light-emitting layer, is positioned closer to the first electrode 210, which serves as a transparent electrode, than the third light-emitting layer 560.

[0295] An encapsulation film (or encapsulation layer) 770 is formed on the second electrode 230 to prevent moisture from penetrating into the OLED D. The encapsulation film 770 may have a structure including an inorganic insulating layer and an organic insulating layer.

[0296] Although not shown, the organic light-emitting display device 700 may include color filters corresponding to the red, green, and blue pixel regions. For example, the color filters may be located between the OLED D and the substrate 710.

[0297] [OLED1]

[0298] An OLED is formed in the green pixel region by sequentially depositing an anode (ITO / APC / ITO), HIL (Equation 9-1, 5nm), HTL (Equation 9-2, 25nm), EBL (Equation 9-3, 10nm), EML (30nm), HBL (Equation 9-4, 10nm), ETL (Equation 9-5, 30nm), EIL (LiF, 3nm), a cathode (Al, 20nm), and a capping layer (Equation 9-6, 100nm).

[0299] [Equation 9-1]

[0300]

[0301] [Equation 9-2]

[0302]

[0303] [Equation 9-3]

[0304]

[0305] [Equation 9-4]

[0306]

[0307] [Equation 9-5]

[0308]

[0309] [Equation 9-6]

[0310]

[0311] 1. Comparative Example

[0312] (1) Comparative Example 1 (Ref 1)

[0313] Compound H1 (92 wt%) in Formula 2 and compound PD1 (8 wt%) in Formula 4 are used to form EML.

[0314] (2) Comparative Example 2 (Ref 2)

[0315] Compound H1 (92 wt%) in Formula 2 and compound PD2 (8 wt%) in Formula 4 are used to form EML.

[0316] (3) Comparative Example 3 (Ref 3)

[0317] Compound H1 (60 wt%) in Formula 2, compound TD1 (39.8 wt%) in Formula 6, and compound FD1 (0.2 wt%) in Formula 8 are used to form EML.

[0318] (4) Comparative Example 4 (Ref 4)

[0319] Compound H1 (60 wt%) in Formula 2, compound TD1 (39.8 wt%) in Formula 6, and compound FD2 (0.2 wt%) in Formula 8 are used to form EML.

[0320] (5) Comparative Example 5 (Ref 5)

[0321] Compound H1 (60 wt%) in Formula 2, compound TD1 (39.8 wt%) in Formula 6, and compound FD3 (0.2 wt%) in Formula 8 are used to form EML.

[0322] [OLED2]

[0323] An OLED is formed in the green pixel region by sequentially depositing an anode (ITO / APC / ITO), HIL (Equation 9-1, 5nm), HTL (Equation 9-2, 25nm), EBL (Equation 9-3, 10nm), first EML (30nm), HBL (Equation 9-4, 10nm), ETL (Equation 9-5, 15nm), N-type CGL (Equation 9-7 (99.5 wt%) + Li (0.5 wt%), 10nm), P-type CGL (Equation 9-1, 8nm), HTL (Equation 9-2, 25nm), EBL (Equation 9-3, 10nm), second EML (30nm), HBL (Equation 9-4, 10nm), ETL (Equation 9-5, 30nm), EIL (LiF, 3nm), cathode (Al, 20nm), and capping layer (Equation 9-6, 100nm).

[0324] [Equation 9-7]

[0325]

[0326] 2. Comparative Example

[0327] (1) Compare Example 6 (Ref 6)

[0328] Compound H1 (60 wt%) of Formula 2, compound TD1 (39.8 wt%) of Formula 6 and compound FD1 (0.2 wt%) of Formula 8 are used to form the first EML, and compound H1 (92 wt%) of Formula 2 and compound PD1 (8 wt%) of Formula 4 are used to form the second EML.

[0329] (2) Comparative Example 7 (Ref 7)

[0330] Compound H1 (92 wt%) of Formula 2 and compound PD1 (8 wt%) of Formula 4 are used to form the first EML, and compound H1 (60 wt%) of Formula 2, compound TD1 (39.8 wt%) of Formula 6 and compound FD1 (0.2 wt%) of Formula 8 are used to form the second EML.

[0331] [OLED3]

[0332] An OLED is formed in the green pixel region by sequentially depositing an anode (ITO / APC / ITO), HIL (Equation 9-1, 5nm), HTL (Equation 9-2, 25nm), EBL (Equation 9-3, 10nm), a first emitting layer (15nm), a second emitting layer (15nm), HBL (Equation 9-4, 10nm), ETL (Equation 9-5, 15nm), an N-type CGL (Equation 9-7 (99.5 wt%) + Li (0.5 wt%), 10nm), a P-type CGL (Equation 9-1, 8nm), HTL (Equation 9-2, 25nm), EBL (Equation 9-3, 10nm), a third emitting layer (15nm), a fourth emitting layer (15nm), HBL (Equation 9-4, 10nm), ETL (Equation 9-5, 30nm), EIL (LiF, 3nm), a cathode (Al, 20nm), and a capping layer (Equation 9-6, 100nm).

[0333] 3. Example

[0334] (1) Example 1 (Ex1)

[0335] Compound H1 (92 wt%) in Formula 2 and compound PD1 (8 wt%) in Formula 4 2nd / I 1st =0.4) is used to form the first luminescent layer, and compound H1 (60 wt%) from Formula 2, compound TD1 (39.8 wt%) from Formula 6, and compound FD1 (0.2 wt%) from Formula 8 are used to form the second luminescent layer. Compound H1 (92 wt%) from Formula 2 and compound PD1 (8 wt%) from Formula 4 are used to form the second luminescent layer. 2nd / I 1st =0.4) is used to form the third luminescent layer, and compound H1 (60 wt%) in Formula 2, compound TD1 (39.8 wt%) in Formula 6 and compound FD1 (0.2 wt%) in Formula 8 are used to form the fourth luminescent layer.

[0336] (2) Example 2 (Ex2)

[0337] Compound H1 (92 wt%) in Formula 2 and compound PD1 (8 wt%) in Formula 4 2nd / I 1st =0.5) is used to form the first luminescent layer, and compound H1 (60 wt%) from Formula 2, compound TD1 (39.8 wt%) from Formula 6, and compound FD1 (0.2 wt%) from Formula 8 are used to form the second luminescent layer. Compound H1 (92 wt%) from Formula 2 and compound PD1 (8 wt%) from Formula 4 are used to form the second luminescent layer. 2nd / I 1st=0.5) is used to form the third luminescent layer, and compound H1 (60 wt%) in Formula 2, compound TD1 (39.8 wt%) in Formula 6 and compound FD1 (0.2 wt%) in Formula 8 are used to form the fourth luminescent layer.

[0338] (3) Example 3 (Ex3)

[0339] Compound H1 (92 wt%) in Formula 2 and compound PD1 (8 wt%) in Formula 4 2nd / I 1st =0.7) is used to form the first luminescent layer, and compound H1 (60 wt%) of Formula 2, compound TD1 (39.8 wt%) of Formula 6, and compound FD1 (0.2 wt%) of Formula 8 are used to form the second luminescent layer. Compound H1 (92 wt%) of Formula 2 and compound PD1 (8 wt%) of Formula 4 are used to form the second luminescent layer. 2nd / I 1st =0.7) is used to form the third luminescent layer, and compound H1 (60 wt%) of Formula 2, compound TD1 (39.8 wt%) of Formula 6 and compound FD1 (0.2 wt%) of Formula 8 are used to form the fourth luminescent layer.

[0340] (4) Example 4 (Ex4)

[0341] Compound H1 (92 wt%) in Formula 2 and compound PD1 (8 wt%) in Formula 4 2nd / I 1st =0.57) is used to form the first luminescent layer, and compound H1 (60 wt%) from Formula 2, compound TD1 (39.8 wt%) from Formula 6, and compound FD1 (0.2 wt%) from Formula 8 are used to form the second luminescent layer. Compound H1 (92 wt%) from Formula 2 and compound PD1 (8 wt%) from Formula 4 are used to form the second luminescent layer. 2nd / I 1st =0.57) is used to form the third luminescent layer, and compound H1 (60 wt%) in Formula 2, compound TD1 (39.8 wt%) in Formula 6 and compound FD1 (0.2 wt%) in Formula 8 are used to form the fourth luminescent layer.

[0342] (5) Example 5 (Ex5)

[0343] Compound H1 (60 wt%) of Formula 2, compound TD1 (39.8 wt%) of Formula 6, and compound FD1 (0.2 wt%) of Formula 8 are used to form the first luminescent layer, and compound H1 (92 wt%) of Formula 2 and compound PD1 (8 wt%) of Formula 4 are used to form the first luminescent layer. 2n d / I 1st=0.57) is used to form the second luminescent layer. Compound H1 (92 wt%) in Formula 2 and compound PD1 (8 wt%) in Formula 4 are used to form the second luminescent layer. 2nd / I 1st =0.57) is used to form the third luminescent layer, and compound H1 (60 wt%) in Formula 2, compound TD1 (39.8 wt%) in Formula 6 and compound FD1 (0.2 wt%) in Formula 8 are used to form the fourth luminescent layer.

[0344] (6) Example 6 (Ex6)

[0345] Compound H1 (92 wt%) in Formula 2 and compound PD1 (8 wt%) in Formula 4 2nd / I 1st =0.57) is used to form the first luminescent layer, and compound H1 (60 wt%) of Formula 2, compound TD1 (39.8 wt%) of Formula 6, and compound FD1 (0.2 wt%) of Formula 8 are used to form the second luminescent layer. Compound H1 (60 wt%) of Formula 2, compound TD1 (39.8 wt%) of Formula 6, and compound FD1 (0.2 wt%) of Formula 8 are used to form the third luminescent layer, and compound H1 (92 wt%) of Formula 2 and compound PD1 (8 wt%) of Formula 4 are used to form the third luminescent layer. 2nd / I 1st =0.57) is used to form the fourth light-emitting layer.

[0346] (7) Example 7 (Ex7)

[0347] Compound H1 (60 wt%) of Formula 2, compound TD1 (39.8 wt%) of Formula 6, and compound FD1 (0.2 wt%) of Formula 8 are used to form the first luminescent layer, and compound H1 (92 wt%) of Formula 2 and compound PD1 (8 wt%) of Formula 4 are used to form the first luminescent layer. 2nd / I 1st =0.57) is used to form the second luminescent layer. Compound H1 (60 wt%) of Formula 2, compound TD1 (39.8 wt%) of Formula 6, and compound FD1 (0.2 wt%) of Formula 8 are used to form the third luminescent layer, and compound H1 (92 wt%) of Formula 2 and compound PD1 (8 wt%) of Formula 4 are used to form the third luminescent layer. 2nd / I 1st =0.57) is used to form the fourth light-emitting layer.

[0348] (8) Example 8 (Ex8)

[0349] Compound H1 (92 wt%) in Formula 2 and compound PD1 (8 wt%) in Formula 4 2nd / I 1st=0.57) is used to form the first luminescent layer, and compound H1 (60 wt%) from Formula 2, compound TD1 (39.8 wt%) from Formula 6, and compound FD2 (0.2 wt%) from Formula 8 are used to form the second luminescent layer. Compound H1 (92 wt%) from Formula 2 and compound PD1 (8 wt%) from Formula 4 are used to form the second luminescent layer. 2nd / I 1st =0.57) is used to form the third luminescent layer, and compound H1 (60 wt%) in Formula 2, compound TD1 (39.8 wt%) in Formula 6 and compound FD2 (0.2 wt%) in Formula 8 are used to form the fourth luminescent layer.

[0350] (9) Example 9 (Ex9)

[0351] Compound H1 (92 wt%) in Formula 2 and compound PD2 (8 wt%) in Formula 4 2nd / I 1st =0.6) is used to form the first luminescent layer, and compound H1 (60 wt%) of Formula 2, compound TD1 (39.8 wt%) of Formula 6, and compound FD3 (0.2 wt%) of Formula 8 are used to form the second luminescent layer. Compound H1 (92 wt%) of Formula 2 and compound PD2 (8 wt%) of Formula 4 are used to form the second luminescent layer. 2na / I 1st =0.6) is used to form the third luminescent layer, and compound H1 (60 wt%) in Formula 2, compound TD1 (39.8 wt%) in Formula 6 and compound FD3 (0.2 wt%) in Formula 8 are used to form the fourth luminescent layer.

[0352] The luminescent characteristics of the OLEDs in Comparative Examples 1-7 and Examples 1-9, namely driving voltage (V), luminance (cd / A), color coordinate index (CIE), maximum emission wavelength (ELmax), FWHM, and lifetime (T95), were measured and are listed in Tables 1 and 2. In Tables 1 and 2, the measured values ​​of Comparative Example 2, Examples 1-3, Example 8, and Example 9 marked with "*" are simulated data.

[0353] Table 1

[0354]

[0355] Table 2

[0356]

[0357]

[0358] As shown in Tables 1 and 2, in the OLEDs of Examples 1-9, wherein the first light-emitting part includes fluorescent and phosphorescent light-emitting layers (i.e., the first and second light-emitting layers), and the second light-emitting part includes fluorescent and phosphorescent light-emitting layers (i.e., the third and fourth light-emitting layers), the luminous efficiency (brightness) and lifetime are improved, and the FWHM is reduced.

[0359] Furthermore, compared with the OLEDs of Examples 1 and 2 (wherein the second emission peak intensity "I" of the phosphorescent dopant) 2nd "Compared with the first launch peak intensity" I 1st The ratio of "I" 2n d / I 1st Compared to (where the second emission peak intensity of the phosphorescent dopant is 0.5 or less), the OLEDs of Examples 3-9 (where the second emission peak intensity of the phosphorescent dopant is 0.5 or less) 2nd "Compared with the first launch peak intensity" I 1st The ratio of "I" 2nd / I 1st The luminous efficiency (0.55 or greater) is significantly improved.

[0360] Furthermore, compared to the OLED of Example 7 (in which the phosphorescent emitting layer is closer to the second electrode serving as a transparent electrode than the fluorescent emitting layer), the OLEDs of Examples 3-6 (in which the fluorescent emitting layer of at least one of the first and second light-emitting portions is closer to the second electrode serving as a transparent electrode than the phosphorescent emitting layer) have significantly improved luminous efficiency and lifetime.

[0361] Furthermore, compared to the OLED of Example 6 (in which the fluorescent luminescent layer in the first luminescent portion, which is closer to the first electrode serving as the reflective electrode, is closer to the second electrode serving as the transparent electrode than the phosphorescent luminescent layer), the OLED of Example 5 (in which the fluorescent luminescent layer in the second luminescent portion, which is closer to the second electrode serving as the transparent electrode, is closer to the second electrode serving as the transparent electrode than the phosphorescent luminescent layer) has advantages in luminous efficiency and FWHM.

[0362] Furthermore, the luminous efficiency and lifetime of the OLED in Example 4 are further improved, wherein the fluorescent luminescent layer in the first and second luminescent parts is closer to the second electrode, which serves as a transparent electrode, than the phosphorescent luminescent layer.

[0363] As described above, the OLED of this disclosure includes first and second light-emitting portions, each including a fluorescent light-emitting layer and a phosphorescent light-emitting layer, and at least one of the first and second light-emitting layers, the fluorescent light-emitting layer is positioned closer to the second electrode, which serves as a transparent electrode. Therefore, the cavity effect is enhanced, improving the characteristics (performance) of the OLED. Specifically, by positioning the fluorescent light-emitting layer, which has a relatively small second emission peak intensity, closer to the transparent electrode, the characteristics (performance) of the OLED are improved.

[0364] In the OLED disclosed herein, the phosphorescent light-emitting layer in the first light-emitting part near the reflective electrode can be configured to be closer to the transparent electrode, and the fluorescent light-emitting layer in the second light-emitting part near the transparent electrode can be configured to be closer to the transparent electrode.

[0365] Furthermore, in the first light-emitting portion near the reflective electrode and the second light-emitting portion near the transparent electrode, the fluorescent light-emitting layer can be positioned closer to the transparent electrode.

[0366] Furthermore, the phosphorescent dopant in the phosphorescent emitting layer has a second emission peak intensity "I". 2nd "Compared with the first launch peak intensity" I 1st The ratio of "I" 2nd / I 1st "A value of 0.55 or greater and 1 or less significantly improves the luminous efficiency (brightness) of OLEDs."

[0367] It will be apparent to those skilled in the art that various modifications and variations can be made to this disclosure without departing from its spirit or scope. Therefore, this invention is intended to cover modifications and variations of this disclosure, provided they fall within the scope of the appended claims and their equivalents.

Claims

1. An organic light-emitting diode, comprising: Reflective electrode; A transparent electrode facing the reflective electrode; and An organic light-emitting layer comprising a first light-emitting portion and a second light-emitting portion and located between the reflective electrode and the transparent electrode. The first light-emitting part includes a first light-emitting material layer, and the second light-emitting part includes a second light-emitting material layer. Each of the first luminescent material layer and the second luminescent material layer comprises a bilayer structure having a green phosphorescent luminescent layer and a green fluorescent luminescent layer. In at least one of the first light-emitting portion and the second light-emitting portion, the green fluorescent light-emitting layer is positioned closer to the transparent electrode than the green phosphorescent light-emitting layer. The green phosphorescent layer in each of the first and second light-emitting portions comprises a first compound represented by Formula 1-1 and a second compound represented by Formula 3, wherein the second compound has a weight percentage of 1-20% relative to the first compound. The green fluorescent luminescent layer in each of the first and second luminescent portions comprises a third compound represented by Formula 1-1, a fourth compound represented by Formula 5-1, and a fifth compound represented by Formula 7, wherein the fourth compound has a weight percentage of 60-80% relative to the third compound, and the fifth compound has a weight percentage of 0.1-10% relative to the third compound. [Equation 1-1] ， In Formula 1-1, Ar is selected from the group consisting of substituted or unsubstituted C6-C30 aryl groups and substituted or unsubstituted C5-C30 heteroaryl groups, and R1, R2, R3, and R4 are each independently selected from the group consisting of substituted or unsubstituted C1-C10 alkyl groups and substituted or unsubstituted C6-C30 aryl groups. Where a1, a2, a3, and a4 are each independent integers from 0 to 4. [Formula 3] ， In Formula 3, R11 and R12 are each independently selected from the group consisting of halogens, substituted or unsubstituted C1-C10 alkyl groups, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C5-C30 heteroaryl groups, and b1 and b2 are each independently integers from 0 to 4. R13 and R14 are each independently selected from the group consisting of hydrogen, halogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C5-C30 heteroaryl. [Equation 5-1] ， In Equation 5-1, c1 is an integer from 1 to 4, and Y is represented by Equation 5-2: [Equation 5-2] ， In Formula 5-2, R21 and R22 are each independently selected from the group consisting of substituted or unsubstituted C1-C10 alkyl groups, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C5-C30 heteroaryl groups, or at least one of two adjacent R21s and two adjacent R22s is interconnected to form an aromatic ring or a heteroaromatic ring. Where c2 and c3 are each an independent integer between 0 and 4. [Formula 7] ， In Formula 7, R31, R32, R33, R34, R35, R36 and R37 are each independently selected from the group consisting of hydrogen, substituted or unsubstituted C1-C10 alkyl groups, and substituted or unsubstituted C6-C30 aryl groups, and at least one of R31, R32, R33 and R34 is a substituted or unsubstituted C1-C10 alkyl group.

2. The organic light-emitting diode according to claim 1, wherein the photoluminescence spectrum of the green fluorescent light-emitting layer in the first light-emitting part includes a first emission peak and a second emission peak, and the wavelength of the second emission peak is longer than the wavelength of the first emission peak. The photoluminescence spectrum of the green phosphorescent layer in the first light-emitting part includes a first emission peak and a second emission peak, and the wavelength of the second emission peak is longer than the wavelength of the first emission peak. The intensity of the second emission peak of the green fluorescent light-emitting layer in the first light-emitting part is less than the intensity of the second emission peak of the green phosphorescent light-emitting layer in the first light-emitting part.

3. The organic light-emitting diode according to claim 2, wherein the photoluminescence spectrum of the green fluorescent light-emitting layer in the second light-emitting part includes a first emission peak and a second emission peak, and the wavelength of the second emission peak is longer than the wavelength of the first emission peak. The photoluminescence spectrum of the green phosphorescent layer in the second light-emitting part includes a first emission peak and a second emission peak, and the wavelength of the second emission peak is longer than the wavelength of the first emission peak. The intensity of the second emission peak of the green fluorescent light-emitting layer in the second light-emitting part is less than the intensity of the second emission peak of the green phosphorescent light-emitting layer in the second light-emitting part.

4. The organic light-emitting diode according to claim 3, wherein the green phosphorescent light-emitting layer in each of the first light-emitting portion and the second light-emitting portion comprises the first compound as the main body and the second compound as the light-emitting element, and In the second compound, the ratio of the intensity of the second emission peak to the intensity of the first emission peak is greater than 0.55 and less than 1.

5. The organic light-emitting diode according to claim 1, wherein the second light-emitting portion is located between the first light-emitting portion and the transparent electrode, and In the second light-emitting part, the green fluorescent light-emitting layer is positioned closer to the transparent electrode than the green phosphorescent light-emitting layer.

6. The organic light-emitting diode according to claim 5, wherein in the first light-emitting portion, the green fluorescent light-emitting layer is positioned closer to the transparent electrode than the green phosphorescent light-emitting layer.

7. The organic light-emitting diode according to claim 5, wherein in the first light-emitting portion, the green phosphorescent light-emitting layer is positioned closer to the transparent electrode than the green fluorescent light-emitting layer.

8. The organic light-emitting diode according to claim 1, wherein formula 1-1 is represented by formula 1-2: [Equation 1-2] ， In Formula 1-2, R5 and R6 are each independently selected from the group consisting of substituted or unsubstituted C1-C10 alkyl groups and substituted or unsubstituted C6-C30 aryl groups, and a5 and a6 are each independently integers from 0 to 4. The definitions of R1, R2, R3, R4, a1, a2, a3, and a4 are the same as in Formula 1-1.

9. The organic light-emitting diode according to claim 1, wherein the first compound is one of the compounds in formula 2: [Equation 2] 。 10. The organic light-emitting diode according to claim 1, wherein the second compound is one of the compounds in formula 4: [Formula 4] 。 11. The organic light-emitting diode according to claim 1, wherein the fourth compound is one of the compounds in formula 6: [Formula 6] 。 12. The organic light-emitting diode according to claim 1, wherein the fifth compound is one of the compounds in formula 8: [Formula 8] 。 13. An organic light-emitting display device, comprising: A substrate, the substrate comprising a red pixel region, a green pixel region, and a blue pixel region; and The organic light-emitting diode according to any one of claims 1-12 is disposed on or above the substrate and located in the green pixel region.

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