KR20160057045A - Organic light emitting device and organic light emitting display having the same - Google Patents

Abstract

The objective of the present invention is to provide an organic light emitting device with an improved luminous efficiency. An organic light emitting display device comprises an organic light emitting device. The organic light emitting device includes a light emitting layer, and the light emitting layer includes: a first host including a fluorescent material; a second host including a delayed fluorescent material; and a light emitting dopant. A singlet excitation energy level of the second host is greater than the singlet excitation energy level of the light emitting dopant.

Description

TECHNICAL FIELD [0001] The present invention relates to an organic light emitting diode (OLED) and an organic light emitting diode (OLED)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting diode and an organic light emitting diode display including the same. More particularly, the present invention relates to an organic light emitting diode including a fluorescent material, a retardation fluorescent material and a luminescent dopant, will be.

Various display devices used in multimedia devices such as televisions, mobile phones, tablet computers, navigation systems, game machines, and the like are being developed.

One of such display devices is an organic light emitting display (OLED). The organic light emitting display device is a self-luminous display device having a wide viewing angle, excellent contrast, and high response speed.

The organic light emitting display includes an organic light emitting device, and the light emitting layer of the organic light emitting device may be formed of a single material. Further, the light emitting layer may be made of a mixture of a host material and a dopant material.

Examples of the light-emitting material used in the organic light-emitting device include fluorescent materials and retarded fluorescent materials, and retarded fluorescent materials are usually used for increasing the luminous efficiency.

It is an object of the present invention to provide a host in which a light emitting layer includes a fluorescent material, a host including a retardation fluorescent material, and an organic light emitting element including a luminescent dopant to increase the light emitting efficiency.

It is another object of the present invention to provide an organic light emitting display device including the organic light emitting device.

An organic light emitting diode display according to an embodiment of the present invention includes an organic light emitting diode.

 The organic light emitting device includes an anode, a cathode, a light emitting layer, and an electron transporting region. The cathode is spaced apart from the anode. The light emitting layer is disposed between the anode and the cathode. The electron transporting region injects / transports electrons from the cathode to the light emitting layer. The light emitting layer includes a first host, a second host, and a luminescent dopant. The first host comprises a fluorescent material. The second host includes a retarding fluorescent material. The excited singlet energy level of the second host is greater than the excited singlet energy level of the luminescent dopant.

The difference between the excitation triplet energy level and the excitation triplet energy level of the second host may be 0.01 eV to 0.02 eV in the organic light emitting device according to an embodiment of the present invention.

In the organic light emitting diode according to an exemplary embodiment of the present invention, the difference between the excited-singlet energy level of the second post and the excited-singlet excitation energy level of the light emitting dopant may be 0.1 eV to 0.7 eV.

In the organic light emitting device according to an embodiment of the present invention, the excitation energy energy level of the first host may be greater than the excitation energy energy level of the second host.

The volume of the second host may be 10% to 50% of the volume of the light emitting layer in the organic light emitting device according to an embodiment of the present invention.

The organic light emitting device according to an embodiment of the present invention may include an organometallic compound in which the second host includes at least one of Ir, Pt, Os, Re, Eu, and Tb.

The organic light emitting device according to an embodiment of the present invention may further include a hole transporting region for injecting / transporting holes from the anode to the light emitting layer.

According to the above description, the organic light emitting device including the fluorescent material, the retardation fluorescent material, and the light emitting layer including the light emitting dopant has good color reproducibility due to the fluorescent material, has a long life span, and has good internal quantum efficiency of the retardation fluorescent material. Efficiency is improved.

1 is a cross-sectional view of an organic light emitting diode according to an embodiment of the present invention.
2 is a graph showing energy levels of materials included in the light emitting layer of the organic light emitting device according to an embodiment of the present invention.

The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In the drawings, the scale of some components is exaggerated or reduced in order to clearly represent layers and regions. Like reference numerals refer to like elements throughout the specification. And, a layer is formed (placed) on another layer includes not only when the two layers are in contact but also when there is another layer between the two layers. Further, although one surface of a certain layer is shown as flat in the drawing, it is not necessarily required to be flat, and a step may occur on the surface of the upper layer due to the surface shape of the lower layer in the laminating process.

Hereinafter, an organic light emitting diode according to an embodiment of the present invention and an organic light emitting diode display including the same will be described with reference to the drawings.

The OLED display includes a gate driver (not shown), a data driver (not shown), and a display panel (not shown).

The gate driver receives the gate control signal from the timing controller. The gate driver generates a plurality of gate signals, and sequentially outputs the plurality of gate signals to a plurality of gate lines, which will be described later. The gate driving unit generates a plurality of emission control signals in response to the gate control signal and outputs a plurality of emission control signals to a plurality of emission lines to be described later.

The data driver receives the data control signal and the image data from the timing controller. The data driver converts the image data into data signals, and outputs the data signals to a plurality of data lines insulated from the gate lines. The data signals are analog voltages corresponding to the gray level values of the image data.

The display panel unit includes a plurality of gate lines, a plurality of light emitting lines, a plurality of data lines, and a plurality of pixels. Each of the plurality of light emitting lines may be arranged in parallel to a corresponding one of the plurality of gate lines.

Each of the plurality of pixels is connected to a corresponding one of a plurality of gate lines, a corresponding one of the plurality of light emitting lines, and a corresponding one of the plurality of data lines.

The pixels include an organic light emitting element and a circuit portion for controlling the organic light emitting element. The circuit portion may include a first transistor, a second transistor, and a capacitor. However, it is not limited thereto.

The first transistor outputs a data signal applied to the data line in response to a gate signal applied to the gate line.

The capacitor charges the voltage corresponding to the data signal received from the first transistor.

The second transistor controls a driving current flowing to the organic light emitting element corresponding to the voltage stored in the capacitor.

1 is a cross-sectional view of an organic light emitting diode according to an embodiment of the present invention. 2 is a graph showing energy levels of materials included in the light emitting layer of the organic light emitting device according to an embodiment of the present invention. Hereinafter, the organic light emitting device will be described in more detail with reference to FIGS. 1 and 2. FIG.

1, an OLED according to an exemplary embodiment of the present invention includes an anode disposed on a base substrate SUB, a cathode CTD disposed apart from the anode, A light emitting layer EML disposed between the anode AND and the cathode CTD; an electron transporting region ETR injecting and transporting electrons from the cathode CTD to the light emitting layer EML; And a hole transporting region (HTR) for injecting / transporting holes into the hole transporting region (HTR). However, the present invention is not limited thereto, and the organic light emitting diode OLED may not include a hole transporting region (HTR) or an electron transporting region (ETR). The base substrate SUB constitutes a display panel unit, and a plurality of signal lines and a driving circuit for driving the organic light emitting devices OLED may be disposed on one surface of the base substrate SUB.

The anode (AND) is disposed on the base substrate (SUB) and has conductivity. The anode (AND) may be a pixel electrode or an anode. The anode (AND) may be a transmissive electrode, a transflective electrode, or a reflective electrode. When the first electrode is a transmissive electrode, the first electrode is made of a transparent metal oxide such as ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), ITZO (indium tin zinc oxide) Lt; / RTI > The first electrode may include a mixture of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, or a metal if the first electrode is a transflective electrode or a reflective electrode. The first electrode may be a multi-layer structure having a single layer or a plurality of layers made of a transparent metal oxide or metal. For example, the first electrode may be a single-layer structure of ITO, Ag or a metal mixture (e.g., a mixture of Ag and Mg), a two-layer structure of ITO / Mg or ITO / But is not limited thereto.

The cathode CTD is disposed apart from the anode (AND), and may be made of a metal having a low work function, an alloy, an electrically conductive compound, or a mixture thereof. The cathode CTD may be a common electrode or a cathode.

The cathode CTD may be a transmissive electrode, a transflective electrode, or a reflective electrode. When the cathode CTD is a transmissive electrode, the cathode CTD may be formed of Li, Ca, LiF / Ca, LiF / Al, Al, Mg, Ag or a compound or mixture thereof . The cathode CTD may include an auxiliary electrode. The auxiliary electrode may include a transparent metal oxide such as ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), ITZO (indium tin zinc oxide) When the cathode CTD is a transflective electrode or a reflective electrode, the cathode CTD may be formed of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Al, or a compound or mixture thereof (e.g., a mixture of Ag and Mg). Or a transparent metal oxide formed of ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), ITZO (indium tin zinc oxide), or the like.

When the organic light emitting diode OLED is a front emission type, the anode (AND) is a reflective electrode and the cathode CTD is a transmissive electrode or a transflective electrode. When the organic light emitting diode OLED is of a backlight type, the anode (AND) may be a transmissive electrode or a transflective electrode, and the cathode CTD may be a reflective electrode. However, the electrodes of the anode (AND) and the cathode (CTD) are not limited thereto.

The electron transport region (ETR) injects / transports electrons into the light emitting layer (EML).

The electron transport region (ETR) may include, but is not limited to, an electron transport layer (ETL) and an electron injection layer (EIL).

As shown in Fig. 1, the electron transport region ETR may have an electron transport layer (ETL) / electron injection layer (EIL) structure sequentially stacked from the light emitting layer (EML). In addition, it may have a single layer structure in which two or more layers are mixed, but is not limited thereto.

The electron transport region (ETR) can be formed by a variety of methods such as vacuum deposition, spin coating, casting, Langmuir-Blodgett, inkjet printing, laser printing, and laser induced thermal imaging .

When the electron transporting region (ETR) comprises an electron transporting layer (ETL), the electron transporting region (ETR) comprises Alq3 (Tris (8- hydroxyquinolinato) aluminum; Tris (8- hydroxyquinolinato) aluminum), TPBi (1-phenyl-1H-benzo [d] imidazol-2-yl) Phenyl), BCP (2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline; 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), Bphen -Diphenyl-1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline), TAZ (3- (4-Biphenylyl) -4-phenyl- 4-phenyl-5-tertiary-butylphenyl-1,2,4-triazole), NTAZ (4- (Naphthalen-1-yl) -3,5 -diphenyl-4H-1,2,4-triazole, 4- (naphthalen-1-yl) -3,5-diphenyl-4H-1,2,4- triazole), tBu- -Biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole; 2- (4-biphenylyl) Oxadiazole), BAlq (Bis (2-methyl-8-quinolinolato-N1, O8) - (1,1'-Biphenyl- Beryllium bis (benzoquinolin-10-olate)), ADN (9, 11) (Naphthalene-2-yl) anthracene, 9,10-di (naphthalen-2-yl) anthracene), or mixtures thereof. The thickness of the electron transport layer (ETL) may be from about 100 A to about 1000 A. When the thickness of the electron transport layer (ETL) satisfies the above-described range, satisfactory electron transport characteristics can be obtained without substantial increase in driving voltage.

The electron transport region (ETR) The electron injection layer when comprise (EIL), an electron transport region (ETR) are LiF, LiQ (Lithium quinolate; lithium quinol _{rate), Li 2 O, BaO,} NaCl, CsF, such as Yb A lanthanum group metal, or a halogenated metal such as RbCl and RbI, but the present invention is not limited thereto. The electron injection layer (EIL) may also be made of a mixture of an electron transport material and an insulating organometal salt. The organometallic salt may be a material having an energy band gap of about 4 eV or more. Specifically, for example, the organometallic salt includes a metal acetate, a metal benzoate, a metal acetoacetate, a metal acetylacetonate or a metal stearate . The thickness of the electron injection layer (EIL) may be between about 1 A and about 100 A. When the thickness of the electron injection layer (EIL) satisfies the above-described range, satisfactory electron injection characteristics can be obtained without substantial increase in driving voltage.

The hole transporting region (HTR) injects / transports holes into the light emitting layer (EML).

The hole transporting region HTR may include at least one of a hole injecting layer (HIL), a hole transporting layer (HTL), and an electron blocking layer (not shown).

The hole transporting region (HTR) may have a single layer of a single material, a single layer of a plurality of different materials, or a multi-layer structure having a plurality of layers of a plurality of different materials.

For example, the hole transporting region HTR may have a structure of a single layer made of a plurality of different materials, a hole injection layer / hole transporting layer sequentially stacked from the anode (AND), or a hole injection layer / But it is not limited thereto.

The hole transporting region HTR can be formed by a variety of methods such as vacuum deposition, spin coating, casting, Langmuir-Blodgett, inkjet printing, laser printing, and laser induced thermal imaging .

When the hole transporting region HTR includes a hole injection layer HIL, the hole transporting region HTR may include a phthalocyanine compound such as copper phthalocyanine; DNTPD (N, N'-diphenyl-N, N'-bis- [4- (phenyl-m-tolyl-amino) -phenyl] Diamine), m-MTDATA (4,4 ', 4 "-tris (3-methylphenylphenylamino) triphenylamine, 4,4 ', 4 "-tris (3-methylphenylphenylamino) triphenylamine), TDATA (4,4'4" -Tris (N, N'-diphenylamino) triphenylamine), 2TNATA (4,4 ', 4 "-tris { PEDOT / PSS (poly (3,4-ethylenedioxythiophene) / poly (4-styrenesulfonate); poly (3, (Polyaniline / camphor sulfonic acid), PANI / DBSA (polyaniline / dodecylbenzenesulfonic acid), PANI / CSA (polyaniline / camphor sulfonic acid) PANI / PSS (polyaniline) / poly (4-styrenesulfonate), polyaniline / poly (4-styrenesulfonate) But it can be, but is not limited to such. The thickness of the hole injection layer (HIL) may be about 100 Å to about 10,000 Å. When the thickness of the hole injection layer (HIL) satisfies the above-described range, satisfactory hole injection characteristics can be obtained without substantially increasing the driving voltage.

When the hole transporting region HTR includes a hole transporting layer HTL, the hole transporting region HTR may be a carbazole-based derivative such as N-phenylcarbazole or polyvinylcarbazole, a fluorine-based derivative, a TPD N, N'-bis (3-methylphenyl) -N, N'-diphenyl- [1,1-biphenyl] -4,4'- (4,4 ', 4 "-tris (N, N'-bis (1-naphthyl) -N, N'-diphenylbenzidine, N, N'-di (1-naphthyl) N, N'-diphenylbenzidine), TAPC (4,4'-Cyclohexylidene bis [N, N-bis (4-methylphenyl) benzenamine], 4-4'cyclohexylidenebis [ -Methylphenyl) benzenamine]), and the like, but is not limited thereto. The thickness of the hole transporting layer (HTL) may be about 50 Å to about 2000 Å. When the thickness of the hole transporting layer (HTL) satisfies the above-described range, satisfactory hole transporting characteristics can be obtained without substantial increase in driving voltage.

In addition to the above-mentioned materials, the hole transporting region (HTR) may further include a charge generating material for improving conductivity. The charge generating material may be uniformly or non-uniformly dispersed in the hole transporting region (HTR). The charge generating material may be, for example, a p-dopant. The p-dopant may be, but is not limited to, one of quinone derivatives, metal oxides, and cyano group-containing compounds. For example, non-limiting examples of p-dopants include TCNQ (tetracyanoquinodimethane) and F4-TCNQ (2,3,5,6-tetrafluoro-tetracyanoquinodimethane; - tetrafluoro-tetracano-1,4-benzoquinone dimethine) and the like; Tungsten oxide, molybdenum oxide, and the like, but the present invention is not limited thereto.

The light emitting layer (EML) is disposed between the anode (AND) and the cathode (CTD).

The mechanism of the organic light emitting device emits electrons in the cathode CTD when electrons are applied to the organic light emitting device OLED, and holes in the anode AND are recombined in the light emitting layer EML. When electrons and electrons are encountered in the emission layer (EML), they form an exciton through recombination, and the excitons emit light while transitioning to the ground state. The excited state of the excitons where electrons and holes are formed is a singlet state excited state and a triplet state excited state. Statistically, the singlet and triplet are formed at a ratio of 1: 3. Fluorescence is observed in singlet state and phosphorescence is observed in triplet state. Phosphorescence is observed only at the cryogenic temperature because the thermal transition is common at room temperature and can not be observed. Therefore, the maximum internal quantum efficiency of the fluorescent material is 25%, which is the ratio of the singlet excited states in the total excitons.

However, in the case of the retardation fluorescent material, it is theoretically possible to make the internal quantum efficiency of the organic light emitting device OLED 100% by switching from the triplet state at room temperature to the singlet state and effectively emitting light. Therefore, when the retarding fluorescent material is used as a host in the light emitting layer (EML), the internal quantum efficiency is increased.

When the retardation fluorescent material is used alone for the light emitting layer (EML) of the organic light emitting device (OLED), there is a problem that the life time is shorter and the color reproducibility is worse than the case of using the fluorescent material.

Therefore, in the present invention, an organic light emitting diode (OLED) having a long lifetime and good color reproducibility while increasing internal quantum efficiency using two kinds of host materials by mixing with a fluorescent material, rather than using a delayed fluorescent material alone as a host material, Lt; / RTI >

As shown in FIG. 2, the excited singlet energy level (S1-2) of the second host is greater than the excited singlet energy level (S1-3) of the luminescent dopant. Therefore, the second host does not transition from the excited singlet energy level (S1-2) to the second host's base energy level (G2) but transitions to the excited singlet energy level (S1-3) of the luminescent dopant . Then, the energy is emitted by transitioning from the excitation energy level (S1-3) of the luminescent dopant to the base energy level (G3) of the luminescent dopant. The base energy level G1 of the first host, the base energy level G2 of the second host, and the base energy level G3 of the light emitting dopant may be different from each other.

In the case of the second host, it is preferable that the difference between the excitation energy level (S1-2) and the excitation triplet energy level (T1-2) is less than 0.2 eV because it includes the retarded fluorescent material. When the difference between the singlet energy level (S1-2) and the excitation triplet energy level (T1-2) is smaller than 0.2 eV, the triplet exciton absorbs heat energy, Can be switched.

The excited singlet energy level (S1-2) of the second host is preferably 0.1 eV to 0.7 eV larger than the excited singlet energy level (S1-3) of the luminescent dopant. When the difference between the excitation energy threshold S1-2 of the second host and the energy excitation energy level S1-3 of the light emitting dopant is less than 0.1 eV, -2), it may not be easy to transition to the excitation energy level (S1-3) of the light emitting dopant. If the difference between the excitation energy threshold S1-2 of the second host and the excitation energy threshold S1-3 of the excitation light excited by the second host exceeds 0.7 eV, it may be difficult to emit light of the visible light region have.

The excitation energy threshold S1-1 of the first host may be greater than the energy excitation energy level S1-2 of the second host. If the excitation energy energy level (S1-1) of the first host is greater than the excitation energy energy level (S1-2) of the second host, then the energy is greater than the excitation energy energy level Lt; / RTI > to the excited singlet energy level (S1-3) of the luminescent dopant at the excited singlet energy level (S1-2) of the second host.

Preferably, the volume of the second host is between 10 percent and 50 percent of the volume of the emissive layer (EML). When the volume of the second host is less than 10% of the volume of the light emitting layer (EML), the ratio of the second host containing the retarded fluorescent material is too small to have a small internal quantum efficiency improvement effect. On the other hand, when the volume of the second host exceeds 50% of the volume of the light emitting layer (EML), the proportion of the second host containing the retarded fluorescent material is large, which may shorten the lifetime of the organic light emitting element or deteriorate color reproducibility.

The light emitting layer (EML) is not particularly limited as long as it is a commonly used material. For example, the light emitting layer (EML) may be made of a material emitting red, green, and blue light.

The light emitting layer (EML) may comprise a host and a luminescent dopant. The host may comprise a first host comprising a fluorescent material and a second host comprising a retarding fluorescent material.

When the light emitting layer (EML) emits red light, the first host is, for example, PBD: Eu (DBM) 3 (Phen) (tris (dibenzoylmethanato) phenanthoroline europium; tris (dibenzoylmethaneato) phenanthroline europium) Or a fluorescent material including perylene. However, the material of the first host is not limited thereto.

When the light emitting layer (EML) is to emit red, a second host, for example, PtOEP, may include a delayed fluorescence material including Ir (piq) _3, or Btp ₂ Ir (acac). Also, the second host may include an organometallic compound containing any one or more of Ir, Pt, Os, Re, Eu, or Tb. However, the material of the second host is not limited thereto.

When the light emitting layer (EML) emits red light, the light emitting dopant is, for example, PIQIr (acac) (bis (1-phenylisoquinoline) acetylacetonate iridium, bis (1-phenylisoquinoline) acetylacetonate iridium), PQIr (1-phenylquinoline) acetylacetonate iridium, bis (1-phenylquinoline) acetylacetonate iridium, PQIr (tris (1-phenylquinoline) iridium, bis (1-phenylquinoline) acetylacetonate iridium (pqIr A metal complex or an organometallic complex such as tris (1-phenylquinoline iridium) and PtOEP (octaethylporphyrin platinum), provided that the material of the luminescent dopant is But is not limited thereto.

When the light emitting layer (EML) emits green, the first host may include a fluorescent material including, for example, Alq3 (tris (8-hydroxyquinolino) aluminum; tris (8-quinolinolato) aluminum). However, the material of the first host is not limited thereto.

When the light emitting layer (EML) is to emit light of green, the second host, for _{example, Ir (ppy) 3, Ir} (ppy) 2 (acac), or Ir (mpyp) may include a delayed fluorescent material, including ₃ have. Also, the second host may include an organometallic compound containing any one or more of Ir, Pt, Os, Re, Eu, or Tb. However, the material of the second host is not limited thereto.

When the light emitting layer (EML) emits green, the luminescent dopant is a metal complex compound such as Ir (ppy) 3 (fac-tris (2-phenylpyridine) iridium; pack-tris (2-phenylpyridine) metal complex or organometallic complex. However, the material of the luminescent dopant is not limited thereto.

When the light emitting layer (EML) emits blue light, the first host may be, for example, spiro-DPVBi, spiro-6P, distyryl-benzene, DSA distyryl-arylene, distyrylarylene), PFO (polyfluorene), and PPV (poly (p-phenylene vinylene) Material, but the material of the first host is not limited thereto.

When the light emitting layer (EML) is to emit blue light, the second host, for _{example, F 2 Irpic, (F 2} ppy) 2 Ir (tmd), or Ir (dfppz) may include a delayed fluorescent material, including ₃ have. Also, the second host may include an organometallic compound containing any one or more of Ir, Pt, Os, Re, Eu, or Tb. However, the material of the second host is not limited thereto.

When the light emitting layer (EML) emits blue light, the luminescent dopant can be selected from metal complexes or organometallic complexes such as, for example, (4,6-F2ppy) 2Irpic.

The light emitting layer (EML) may have a single layer made of a single material, a single layer made of a plurality of different materials, or a multi-layered structure having a plurality of layers made of a plurality of different materials.

The light emitting layer (EML) may be formed using various methods such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB), inkjet printing, laser printing, and laser induced thermal imaging (LITI) .

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that various modifications and changes may be made thereto without departing from the scope of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

OLED: organic light emitting element SUB: base substrate
AND: anode HTR: hole transport region
EML: light emitting layer ETR: electron transporting region
CTD: cathode
S1-1: Excitation energy level of the first host
S1-2: Excitation energy level of the second host
S1-3: excitation energy energy level of luminescent dopant
T1-1: excitation triplet energy level of the first host
T1-2: excitation triplet energy level of the second host
T1-3: excitation triplet energy level of luminescent dopant
G1: the base energy level of the first host
G2: the base energy level of the second host
G3: the base energy level of the luminescent dopant

Claims (8)

Anode;
A cathode spaced from the anode;
A light emitting layer disposed between the anode and the cathode;
And an electron transporting region for injecting / transporting electrons from the cathode to the light emitting layer,
The light-
A first host comprising a fluorescent material;
A second host comprising a retarding phosphor material; And
Comprising a luminescent dopant,
Wherein the excited singlet energy level of the second host is greater than the excited singlet energy level of the luminescent dopant. The method according to claim 1,
And the difference between the excitation triplet energy level and the excitation triplet energy level of the second host is 0.01 eV to 0.2 eV. 3. The method of claim 2,
Wherein a difference between an excited singlet energy level of the second host and an excited singlet energy level of the luminescent dopant is 0.1 eV to 0.7 eV. The method of claim 3,
Wherein the excited singlet energy level of the first host is greater than the excited singlet energy level of the second host. 5. The method of claim 4,
And the volume of the second host is 10 to 50 percent of the volume of the light emitting layer. 3. The method of claim 2,
Wherein the second host comprises an organometallic compound containing at least one of Ir, Pt, Os, Re, Eu, or Tb. 3. The method of claim 2,
And a hole transporting region for injecting / transporting holes from the anode to the light emitting layer. An organic light emitting display device comprising the organic light emitting device according to any one of claims 1 to 7.

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