KR101736661B1 - Blue electrophosphorescent organic light emitting device - Google Patents

Abstract

Disclosed is a blue phosphorescent organic light emitting device. The blue phosphorescent organic light emitting device includes: an anode electrode and a cathode electrode spaced apart from each other; a light emitting layer disposed between the anode electrode and the cathode electrode; a hole transport layer disposed between the anode electrode and the light emitting layer; and an electron transport layer disposed between the cathode electrode and the light emitting layer. The electron transport layer is doped with phosphorescent dopant material having triplet energy lower than that of the blue phosphorescent dopant material of the light emitting layer. These blue phosphorescent organic light emitting device has significantly improved durability.

Description

TECHNICAL FIELD [0001] The present invention relates to a blue phosphorescent organic electroluminescent device,

The present invention relates to a blue phosphorescent organic light emitting device having an improved lifetime.

Organic light emitting diodes (LEDs) are a major driving force in information display innovation due to their low power consumption and long lifetime, and are now being applied to mobile display, television, lighting, and other fields. Organic light emitting diodes are classified broadly into fluorescent organic light emitting devices using single-center harbor among singled and triplet excited states formed at a ratio of 1: 3 by quantum spin statistics, and phosphorescent organic light emitting devices using both singlet and triplet . Since the fluorescence organic light emitting device utilizes the one-sided excitation state for light emission, the theoretical internal quantum efficiency limit is only 25%, whereas the phosphorescent organic light emitting device uses both singlet and triplet excited states for light emission, An efficiency limit can be achieved up to 100%.

However, although the phosphorescent organic light emitting device has a remarkably low power consumption characteristic as compared with the fluorescent organic light emitting device and has a high internal quantum efficiency, it can not be applied to the display field for a long time due to the short lifetime of the blue phosphorescent organic light emitting device have. Green, and red phosphorescent organic light-emitting devices have reached a lifetime of up to 50% of the initial luminance (T50) of 10 ⁶ h in decades of research. However, as a blue phosphorescent material, Iridium (III) FIrpic , 6-difluorophenyl) -pyridinato-N,] picolinate) has been reported to be only a few hours in terms of the lifetime of a blue phosphorescent organic light emitting device.

Various studies have been conducted to improve the lifetime of the blue phosphorescent organic light emitting device. However, researches that prolong the lifetime to the level that can be commercialized to date have not been reported.

It is an object of the present invention to provide a blue phosphorescent organic electroluminescent device in which the phosphorescent dopant material is doped to the electron transporting layer disposed adjacent to the luminescent layer to suppress the disappearance of the exciton in the luminescent layer to thereby improve the lifetime of the device.

An organic light emitting device according to an embodiment of the present invention includes an anode electrode and a cathode electrode spaced apart from each other; A light emitting layer disposed between the anode electrode and the cathode electrode, the light emitting layer including a first host material and a blue phosphorescent dopant material; A hole transport layer disposed between the anode electrode and the light emitting layer, the hole transport layer transporting holes injected from the anode electrode to the light emitting layer; And transporting electrons injected from the cathode electrode to the light emitting layer and doping the second host material and the second host material with triplet energy lower than the blue phosphorescent dopant material The branch includes an electron transport layer containing a first phosphorescent dopant material.

In one embodiment, the second host material may include a single host material having an electron transporting property superior to the hole transporting property, or two or more different host materials mixed.

In one embodiment, the second host material is 4,7-diphenyl-1,10-phenanthroline (Bphen), ((2,2 ', 2 - (benzene-1,3,5-triyl) -tris (1-phenyl-1Hbenzimidazole: TPBI), 2,9- dimethyl-4,7-diphenyl-1,10-phenanthroline: BCP), bis (2-methyl-8-quinolinolate) Phenylphenolato aluminum (Balq), 1,3-bis [2- (2,2'-bipyridin-6-yl) -1,3,4-oxadiazol- , 3-bis [2- (2,2'-bipyridine-6-yl) -1,3,4-oxadiazo-5-yl] benzene: Bpy-OXD), 6,6'- Yl) -1,3,4-oxadiazol-2-yl] -2,2'-bipyridyl (6,6'-bis [5- (biphenyl- (4-biphenyl) -4- (phenyl-5-tert-butylphenyl-1,2,3,4-oxadiazo-2-yl] -2,2'-bipyridyl: BP- (4-biphenyl) -4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4- (naphthalen- -4H-1,2,4-triazole (4- (naphthalen-1-yl) -3,5-diphenyl-4H- : NTAZ), 2,9-bis (naphthalen-2-yl) -4,7-diphenyl-1,10-naphthalen- -1,10-phenanthroline: NBphen), tris (2,4,6-trimethyl-3- (pyridin- yl) phenyl) borane: 3TPYMB), phenyl-dipyrenylphosphine oxide (POPy2), 3,3 ', 5,5'-tetra [(m-pyridyl) (3,3 ', 5,5'-tetra [(m-pyridyl) -phen-3-yl] biphenyl: BP4mPy), 1,3,5-tri [ 3-yl] benzene: TmPyPB), 1,3-bis [3,5-di (pyridin-3-yl) phenyl] ] Benzene (BmPyPhB), bis (10-hydroxybenzo [h] quinolinato) beryllium (Bis (10-hydroxybenzo [ bis (10-hydroxybenzo [h] quinolinato) -beryllium: Bebq2), diphenylbis (4- (pyridine- 3- (pyridin-3-yl) phenyl) silane: DPPS), 1,3,5-tri (P-pyrid-3-ylphenyl) benzene: TpPyPB), 3- (4,6-diphenyl- 2-yl) -9-phenyl-9H-carbazole: DPTPCz (5-triazin- ), 2- (3- (3- (N, N-bis (4- (1,1-dimethylethyl) Phenyl) -4-methylphenyl) -4,6-diphenyl-1,3,5-triazin-2-yl) -triazine: tBu-TPA-m-TRZ), 9- (4,6-diphenyl-1,3,5-triazin-2-yl) -9'-phenyl-3,3'-bicabazole (4,6-diphenyl-1,3,5-triazine-2-yl) -9'-phenyl-3,3'- bicarbazole: CzT), 2- (4- (3,6-dimethylcarbazole -9-yl) -phenoxy) -4,6-biscarbazolyl-1,3,5-triazine (4- (3,6-dimethylcarbazol- , 6-biscarbazolyl-1,3,5-triazine: PCTrz), 3- (carbazole-9-yl) -2 ' 9-yl) -1,3'-triazin-2-yl) -1,1'-biphenyl (3- (Carbazol- 2-yl) -1,1'-biphenyl: BPTRZ), 3- (carbazol-9-yl) -6,6'- 9-yl) -6,6'-dimethyl-3 '- ((4-fluorophenyl) 4,6- (dicarbazol-9-yl) -1,3,5-triazin-2-yl) -1,1'-biphenyl: MBPTRZ), Balq (bis (8-hydroxy-2-methylquinolinol Naphtho) -aluminum biphenoxide), and phenanthrolines based compounds.

In one embodiment, the first phosphorescent dopant material may comprise a green phosphorescent dopant material or a red phosphorescent dopant material.

In one embodiment, the doping concentration of the first phosphorescent dopant material over the entire electron transport layer may be between 1 and 30 vol%.

According to the blue phosphorescent organic light emitting device according to the embodiment of the present invention, since the electron transport layer disposed adjacent to the light emitting layer includes the first phosphorescent dopant material having lower triplet energy than the blue phosphorescent dopant doped in the light emitting layer, A part of the generated excitons can move to the triplet state of the first phosphorescent dopant of the electron transport layer, and as a result, the density of the excitons in the light emitting layer can be reduced to improve the lifetime of the device.

1 is a cross-sectional view illustrating a blue phosphorescent organic light emitting device according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. 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 is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing. In the accompanying drawings, the dimensions of the structures are enlarged to illustrate the present invention in order to clarify the present invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the term "comprises" or "having ", etc. is intended to specify that there is a feature, step, operation, element, part or combination thereof described in the specification, , &Quot; an ", " an ", " an "

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

1 is a cross-sectional view illustrating a blue phosphorescent organic light emitting device according to an embodiment of the present invention.

1, a blue phosphorescent organic light emitting diode 100 according to an exemplary embodiment of the present invention includes an anode 110, a hole transport layer 120 disposed on the anode 110, a hole transport layer 120, An electron transport layer 140 disposed on the emission layer 130 and a cathode electrode 150 disposed on the electron transport layer 140.

The anode electrode 110 is disposed on the substrate 10 and may be formed of a conductive material having a high work function. For example, the anode electrode 110 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO 2), zinc oxide (ZnO), or the like, which is transparent and excellent in conductivity.

The hole transport layer 120 may be disposed on the anode electrode 110 and may transport holes injected from the anode electrode 110 to the light emitting layer 130. The material of the hole transport layer 120 is not particularly limited, and conventional hole transport materials can be used without limitation. For example, the hole transport layer 120 may be formed of a mixture of 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPB), 4,4'- Methylphenyl) -N-phenylamino] biphenyl (TPD), 4,4 ', 4 "-tris [(3- methylphenyl) phenylamino] triphenylamine (MTDATA), 1,1- Phenyl) cyclohexane (TAPC), 4- (9H-carbazol-9-yl) -N, N-bis [4- (9H- ] -Benzene amine (TCTA), 9,9 '- [1,1'-biphenyl] -4,4'-diylbis-9H-carbazole (CBP), 9,9' Carbazole (mCP), or N, N, N'N'-tetra [(1,1'-biphenyl) -4-yl] - (1,1'- 4'-diamine (BPBPA), and the like.

The light emitting layer 130 is disposed on the hole transport layer 120. In the light emitting layer 130, holes supplied from the hole transport layer 120 and electrons supplied from the electron transport layer 140 are recombined to generate an exciton, and the generated excitons are excited in the excited state of the triplet state to a ground state And blue phosphorescence can be generated. For this, the light emitting layer 130 may include a first host material for charge transport and a blue phosphorescent dopant material that is doped to the first host material to emit blue phosphorescence.

The first host material is not particularly limited, and the host material used in the conventional blue phosphorescent light-emitting layer 130 may be used without limitation. For example, the first host material can be selected from the group consisting of 1,3-N, N-dicarbazole benzene (mCP), 4,4'-N, N-dicarbazolebiphenyl (CBP), 4,4'- (CDBP), 1,4-bis ((9H-carbazol-9-yl (DCB), trans-1,2-di-9-carbazolylcyclobutane (Ad-Cz), 3,6-di (9-carbazolyl) -9- (2-ethylhexyl) carb N, N ', N''thrazolylmethyl-2,4,6-trimethyl (TCTEB), 2,2'-bis (4-carbazolylphenyl) (4CzPBP), 2,6-bis (3- (9H-carbazol-9-yl) phenyl) pyridine (DCzPPy), bis (2- methylphenyl) diphenylsilane (Triphenylsilyl) benzene (UGH2), 1,3-bis (triphenylsilyl) benzene (UGH3), 4,4'- Phenyl) silane (TPSi-F), 2,6-bis (3- (9H-carbazol-9- yl) phenyl) pyridine (DPCzPSi), 4,4'-bis (Diphenylphosphine oxide) phenyl (PO1), 2,7-bis (diphenylphosphine oxide) (3-hydroxyphenyl) -9,9-dimethylfluorene (PO6), 2,7-dibromofluorene 9H (DBF), spirobifluorene- Phenyl-1H-pyrrole-2,5-diyl) bis (9H-carbazole) (PPyCz2), 9'phenyl 9'H-9 9 '': 6 ', 9' '- tert-butoxide (36PTCz), 8,8-bis (4- (9H- Yl) phenyl) -8- is reacted with indolo [3,2,1-de] acridine (FPCC), 4,40- (8H-indolo [ 6H-carbazol-9-yl) -6H-pyrrolo [3,2,2- 6H-indole-1-yl) -6H pyrrolo [3,2,1 -d] acridine (BIPPA), N, N-diphenyl aniline (DCDPA), 1,1-bis [4- [N, N'-di (p- tolyl) amino] Phenyl] cyclohexane (TAPC), (bis [4- (p, to p 'tolylamino) phenyl] diphenylsilane (DTASi), 9- (3- (9H-carbazol-9-yl) phenyl-3,6-bis (diphenyl) -9H- carbazole (CPBDC), 1,3- (BCPCB), 2,2'-bis (3-tolylaminophenyl) -1,1'-biphenyl (BTPD), tris [3- (Triphenylsilyl) phenyldiphenylphosphine oxide (TSPO1), dibenzofuran (PO14), dibenzothiophene (PO15), bis (4- (4,5 Yl) phenyl) -dimethylsilane (SiTAZ), 8,8-bis (4- (1H-indol-1-yl) phenyl) -8H- (BIPIA), (9- (3- (9H-carbazol-9-yl) phenyl) -9H-carbazol-3-yl) diphenylphosphine (DPPO), 1,3-bis [4- (N, N-dimethylamino) phenyl-1,3,4-oxadiazolyl] Benzene (OXD8), 2,7-bis (diphenyl) -9- [4- (N, N-diphenylamino) phenyl] -9- phenylfluorene (POAPF) ) Phenyl) diphenylphosphine (BCPO), 4-diphenylphosphine oxide-4'- [3- (9H-carbazol-9-yl) -9H-carbazol- (4-methylphenyl) cyclohexyl} phenyl) bis (4-methylphenyl) amine (POPCPA) (4-methylphenyl) diphenylsilyl] phenyl} diphenyl (p-POSiTPA), [(4- (diphenylsilyldiol) (Diphenylphosphine) dioxide (SiDPO), 9- (8- (diphenyl) benzo [B, D] furan-2-yl) -9H-carbazole (DFCzPO) (9H-carbazol-9-yl) -benzo [B, D] thiophene (DBT1), 9- Bis (DBT2), tetrakis (4-sulfonatophenyl) phthalocyanine (TSPC), (9-phenylo-9H (Carbazol-2,5-diyl) bis (diphenylphosphine) oxide (PCPO25), 2,7- Carbazole (PPO27), di (9H-carbazol-9-yl) - (phenyl) phosphine oxide (DCPPO1), 4- (NA- Triphenylamine (DACTA), 4,4 ', 4 "- (N-alkanoyl) -4' - (N-carbamoyl) 9H-3,9'-bicarbazole (pBCb2Cz), 9- (9H-pyrido [ (3'- (9H-carbazol-9-yl) - [1,1'-biphenyl] -3-yl) -9H-pyrido [2,3- b] indole (CzBPCb) Bis (9H pyrido [2,3-B] indol-9-yl) -1,1'biphenyl (CbBPCb), 9 (3 " 1 '2', 1 "-terphenyl] -3-yl) -α-valine (CzOTCb), 3,3" (PCb-DBF), 9- (3- (benzo [B, D] furan-2-yl) phenyl) (PCb-DBz), 9- (3- (9-phenylcarbazol-3-yl) phenyl) -? - carboline (PCb- 9- (3- (9H-carbazol-9-yl) phenyl ) -9H-carbazole-3-carbonitrile (mCPCN), 6- (2- (9H-carbazol- (MCPCzCN), 8- (3- (9H-carbamoyl-phenyl) -9-ethyl-9H-carbazole- Benzo [B, D] furan-2-carbonitrile (m-CzOCN), 8- (3- (9H-carbazol- 2-carbonitrile (m-CzSCN), benzo [B] thiophene (B2tCz), dibenzothiophene (DB2tCz), 6- (carbazol- (PCz-6FP), 3- (3- (9H-carbazol-9-yl) phenyl) benzo [2,3- b] pyridine Benzo [4,5] thieno [2,3-b] pyridine (BTP1) was obtained in the same manner as in [ , 9- (benzo [B, D] furan-2-yl) phenyl) -9H-carbazole (CzDBF), 3,5- (9H-carbazol-9-yl) tetraphenyl (SimCP2), 9'-triphenylsil (9,3 ', 6', 9 "] teracavazone (SitCz), 9,9 '- (oxybis [(1,1'- , 3-diyl) is a compound which can be synthesized by reacting bis (9H -carbazole) (CBBPE), 9- (5 "-phenyl- [1,1'2 ', 1" ] -3-yl) -9H-carbazole (CzTPPh), 9- (3 ', 5 " 3'-yl) -9H-carbazole (CzTPPy), 3,3'-di (9H-carbazol-9-yl) -1,1'2 ', 1''- terphenyl (33DCTP) Al (py (pyrazol-1-yl) pyridin-3-olate) beryllium (BePyPy), tris ), 3 ', 1', 5 ', 5'-bis (diphenylphosphoryl) -9,9' spirobifluorene] (SPPO13) - terphenyl (BTPS), and the like.

The blue phosphorescent dopant material is not particularly limited and a dopant material used in a blue phosphorescent light emitting layer in a conventional organic light emitting device can be used without limitation. For example, the blue phosphorescent dopant material may be selected from the group consisting of FIr6, FIrpic, iridium (III) tris [3- (2,6-dimethylphenyl) -7- methylimidazole [ (III) tris [3- (2,6-dimethylphenyl) -7-methylimidazo [1,2-f] phenanthridine]: Ir (dmp) 3, iridium (III) tris [1- (2,4- diisopropyldibenzo [ (4-fluorophenyl) -1- (5'-isopropyl- [1,1 '] bipyridinium (III) : 3 ', 1 "-terphenyl] -2'-yl) -1H-imidazole (Ir (itpim) 3). The blue phosphorescent dopant material may be doped at a concentration of about 1 to 30 vol% relative to the total volume of the light emitting layer.

The electron transport layer 140 may include a first phosphorescent dopant material disposed on the emissive layer 130 and doped with a second host material and the second host material and having a lower triplet energy than the blue phosphorescent dopant have. The electron transport layer 140 may transport electrons injected from the cathode electrode 150 to the emission layer 130 and may excite excitons in the emission layer 130 due to the presence of the first phosphorescent dopant. It is possible to suppress the light emission and extinction.

The second host material may be formed of a material capable of transporting electrons injected from the cathode electrode 150 to the light emitting layer 130. For example, the second host material can be 4,7-diphenyl-1,10-phenanthroline (Bphen), ((2,2 ', 2 " benzene-1,3,5-triyl-tris (1-phenyl-1Hbenzimidazole: TPBI), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline: BCP), bis (2-methyl-8-quinolinolate) -4 - (phenylphenolato) aluminum: Balq, 1,3-bis [2- (2,2'-bipyridin-6-yl) -1,3,4-oxadiazol- 5-yl] benzene: Bpy-OXD), 6,6'-bis [5- (biphenyl- 4-yl) -1,3,4-oxadiazol-2-yl] -2,2'-bipyridyl (6,6'-bis [5- (biphenyl- 4-oxadiazo-2-yl] -2,2'-bipyridyl: BP-OXD-Bpy), 3- (4- 4-phenyl-5-tert-butylphenyl-1,2,4-triazole: TAZ), 4- (naphthalen- 4- (naphthalen-1-yl) -3,5-diphenyl-4H-1,2,4-triazole: NTAZ), 2,9- Bis (naphthalen-2-yl) -4,7-diphenyl-1,10-phenanthroline: NBphen ), Tris (2,4,6-trimethyl-3- (pyridin-3-yl) phenyl) borane: 3TPYMB) , 3,3 ', 5,5'-tetra [(m-pyridyl) -phen-3-yl] biphenyl (3,3' Tri [3-pyridyl) -phen-3-yl] benzene (1, Bis (3,5-di (pyridin-3-yl) phenyl] benzene (1,3-bis (10-hydroxybenzo [h] quinolinato) beryllium: Bepq2), and a mixture of [3,5-di (pyridin-3-yl) phenyl] benzene: BmPyPhB, , Bis (10-hydroxybenzo [h] quinolinato) beryllium (Bebq2), diphenylbis (4- (pyridin- Diphenylbis (4- (pyridin-3-yl) phenyl) silane: DPPS), 1,3,5- Pyrid-3-ylphenyl) benzene: TpPyPB), 3- (4,6-diphenyl-1,3,5-triazine- -9-phenyl-9H-carbazole: DPTPCz), 2- (3,6-diphenyl-1,3,5-triazin- Phenyl) -4,6-diphenyl-1,3,5-triazine (prepared by reacting 2- (4-methylphenyl) Phenyl) -4,6-diphenyl-1,3,5-triazine: tBu-TPA (4-methylphenyl) -m-TRZ), 9- (4,6-diphenyl-1,3,5-triazin-2-yl) -9'-phenyl-3,3'-bicycarbazole (9- -diphenyl-1,3,5-triazine-2-yl) -9'-phenyl-3,3'-bicarbazole CzT), 2- (4- (3,6-Dimethylcarbazol- 3,6-dimethylcarbazol-9-yl) -phenoxy) -bis-4,6-biscarbazolyl-1 , 3,5-triazine: PCTrz), 3- (carbazole-9-yl) -2'- (4,6- (dicarbazol- ) -1,1'-biphenyl (3- (Carbazol-9-yl) -3 '- (4,6- (dicarbazol-9-yl) -1,3,5-triazin- , 1'-biphenyl: BPTRZ), 3- (carbazole-9-yl) -6,6'-dimethyl- , 3,5-triazin-2-yl) -1,1-biphenyl (3- (Carbazol-9-yl) -6,6'- 2-yl) -1,1'-biphenyl: MBPTRZ), Balq (bis (8-hydroxy- , Phenanthrolines based compounds (e.g., UDC company BCP (bassocouplin)), and the like. Also, the second host material may be mixed with the first host material.

The first phosphorescent dopant material may include a material having lower triplet energy than the blue phosphorescent dopant material doped in the emission layer 130. For example, the first phosphorescent dopant material may comprise a green phosphorescent dopant material or a red phosphorescent dopant material. The red phosphorescent dopant material may be selected from the group consisting of platinum-octaethylporphyrin complex (PtOEP), Ir (btp) 2 (acac) bis (2- (2'-benzothienyl) -pyridinato- (PPy) 2 (acac), Ir (PPy) 3, UDC's GD48, and the like, which are the green phosphorescent dopants, .

As described above, since the first phosphorescent dopant material has lower triplet energy than the blue phosphorescent dopant material doped in the light emitting layer 130, a part of the triplet excited excitons of the blue phosphorescent dopant material may be doped with the first phosphorescent dopant It is possible to prevent the exciton from being excited by the excitation light in the light emitting layer 130. As a result, it is possible to improve the lifetime of the blue phosphorescent organic light emitting diode 100 according to the present invention have.

In one embodiment, in the electron transport layer 140, the first phosphorescent dopant material may be doped to a concentration of about 1 to 30 vol%. If the doping concentration of the first phosphorescent dopant is less than 1 vol%, the efficiency of energy transfer in the emissive layer 130 may be low, resulting in an excessively low efficiency. If the doping concentration of the first phosphorescent dopant is less than 30 vol %, The color purity of light emitted from the blue phosphorescent organic light emitting diode 100 according to the present invention may be lowered and the efficiency may be lowered due to the concentration quenching phenomenon. For example, the doping concentration of the first phosphorescent dopant in the electron transport layer 140 may be lower than the doping concentration of the blue phosphorescent dopant in the emission layer 130.

The cathode electrode 150 is disposed on the electron transport layer 140, and electrons can be injected into the electron transport layer 140. The cathode electrode 150 may be formed of a metal having a low work function as a metal such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, As shown in FIG. Meanwhile, the cathode electrode 150 may have a multilayer structure such as LiF / Al, LiO2 / Al, or the like.

The blue phosphorescent organic light emitting diode 100 according to an exemplary embodiment of the present invention is disposed between the anode 110 and the hole transport layer 120 to inject holes injected from the anode 110 into the hole transport layer A hole injecting layer 160 for transferring electrons injected from the cathode electrode 150 to the electron transporting layer 140 and a hole injecting layer 160 for transferring electrons injected from the cathode electrode 150 to the electron transporting layer 140. [ An injection layer 170, and the like.

The hole injecting layer 160 and the electron injecting layer 170 may be applied to a conventional organic electroluminescent device without any limitations, so a detailed description thereof will be omitted.

 In general, the deterioration of the blue phosphorescent organic light emitting device is known to result from the formation of traps acting as the center of exciton excitation and non-luminescent charge recombination, and triplet exciton extinguishing by a common layer. Specifically, the traps are formed because of the two molecules of triplet-polaron extinction (TPA), and in the traps, energy is known to pass from the triplet to the polaron and disappear. Compared with the red or green phosphorescent organic light emitting device 100, the blue phosphorescent organic light emitting device 100 has a high triplet energy, so that the energy to be extinguished through the triplet-polaron annihilation (TPA) is remarkably high As a result, the blue phosphorescent organic light emitting device 100 has a significantly higher degradation rate than the red or green phosphorescent organic light emitting device 100. This triplet anti-polaron disappearance can be improved by controlling the formation of the triplet exciton and polaron inside the device through charge balance. Triplet exciton destruction by a common layer material, another cause of lifetime reduction, can be improved by using a common layer with high triplet energies. However, it is difficult to develop a hole transporting layer and an electron transporting layer material having high triplet energy and excellent stability, and thus it has a limitation in the development of a common layer material. Therefore, when a luminescent layer doped with a green or red phosphorescent dopant which does not extinguish the exciton of the luminescent layer is used as an electron transport layer in contact with the luminescent layer, the triplet exciton extinction can be prevented and lifetime can be improved.

According to the blue phosphorescent organic light emitting device 100 according to the embodiment of the present invention, the electron transport layer 140 disposed adjacent to the light emitting layer 130 has a triplet energy lower than that of the blue phosphorescent dopant doped in the light emitting layer 130 A part of the excitons generated in the light emitting layer 130 can move to the triplet of the first phosphorescent dopant of the electron transport layer 140. As a result, And the lifetime of the blue phosphorescent organic light emitting diode 100 can be improved by decreasing extinction.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims. It can be understood that it is possible.

Claims (5)

An anode electrode and a cathode electrode spaced apart from each other;
A light emitting layer disposed between the anode electrode and the cathode electrode, the light emitting layer including a first host material and a blue phosphorescent dopant material;
A hole transport layer disposed between the anode electrode and the light emitting layer, the hole transport layer transporting holes injected from the anode electrode to the light emitting layer; And
Wherein the first host material and the second host material are disposed in contact with the light emitting layer between the cathode electrode and the light emitting layer and transport electrons injected from the cathode electrode to the light emitting layer, And an electron transport layer containing a first phosphorescent dopant material having a triplet energy and a part of the excitons generated in the light emitting layer migrate. The method according to claim 1,
The second host material may include one host material having an electron transporting property superior to a hole transporting property, or an organic light emitting device 3. The method of claim 2,
The second host material may be selected from the group consisting of 4,7-diphenyl-1,10-phenanthroline (Bphen), ((2,2 ', 2 "- (benzene-1 , 3,5-triyl) -tris (1-phenyl-1Hbenzimidazole: TPBI), 2,9-dimethyl-4,17-phenanthroline, diphenyl-1,10-phenanthroline: BCP), bis (2-methyl-8-quinolinolate) -4- (phenylphenolato) bis (2, 2'-bipyridin-6-yl) -1,3,4-oxadiazol-5-yl] benzene - (2,2'-bipyridine-6-yl) -1,3,4-oxadiazo-5-yl] benzene: Bpy-OXD), 6,6'- -1,3,4-oxadiazol-2-yl] -2,2'-bis [5- (biphenyl-4-yl) -1,3,4-oxadiazo- 2-yl] -2,2'-bipyridyl: BP-OXD-Bpy), 3- (4-biphenyl) -4- - (4-biphenyl) -4-phenyl-5-tert-butylphenyl-1,2,4-triazole TAZ, 4- (naphthalen- , 4-triazole (NTAZ), 2,9-bis (naphthol-1-yl) 2-yl) -4,7-diphenyl-1,10-phenanthroline (NBphen), and 2,7-diphenyl-1,10-phenanthroline Tris (2,4,6-trimethyl-3- (pyridin-3-yl) phenyl) borane: 3TPYMB), phenyl 3,3 ', 5,5'-tetra [(m-pyridyl) -phen-3-yl] biphenyl (3,3', 5,5'-tetramethylpiperidine) , 3'-tetra [(3-pyridyl) -phen-3-yl] biphenyl: BP4mPy) Bis (3-pyridyl) -phen-3-yl] benzene: , 5-di (pyridin-3-yl) phenyl] benzene: BmPyPhB), bis (10-hydroxybenzo [h] quinolinato) beryllium: Bepq2) (10-hydroxybenzo [h] quinolinato) -bearylum: Bebq2), diphenylbis (4- (pyridin-3- yl) phenyl) silane (Diphenylbis 4- (pyridin-3-yl) phenyl) silane: DPPS), 1,3,5-tri (p- 3-ylphenyl) benzene: TpPyPB), 3- (4,6-diphenyl-1,3,5-triazin- Phenyl- 9H-carbazole: DPTPCz), 2- (3- (3- (N (N ' Phenyl) -4,6-diphenyl-1,3,5-triazine (2- (3- (3-tert-butylphenyl) Phenyl-4,6-diphenyl-1,3,5-triazine: tBu-TPA-m-TRZ), Synthesis of 9- (4,6-diphenyl-1,3,5-triazin-2-yl) -9'-phenyl-3,3'-bicarbazole , 5-triazine-2-yl) -9'-phenyl-3,3'-bicarbazole CzT), 2- (4- (3,6- dimethylcarbazol- 3,6-dimethylcarbazol-9-yl) -phenoxy) -bis-4,6-biscarbazolyl-1,3,5-triazine : PCTrz), 3- (carbazol-9-yl) -2 '- (4,6- (dicarbazol-9- -Biphenyl (3- (Carbazol-9-yl) -3'- (4,6- (dicarbazol-9-yl) -1,3,5- triazin- 2- yl) -1,1'- BPTRZ), 3- (carbazol-9-yl) -6,6 'dimethyl-3' - (4,6- (dicarbazol- Yl) -6, 1'-dimethyl-3 '- (4,6- (dicarbazol-9-yl) -1,3 , 5-triazin-2-yl) -1,1'-biphenyl: MBPTRZ), Balq (bis (8- And at least one material selected from the group consisting of an organic compound and a base compound. The method according to claim 1,
Wherein the first phosphorescent dopant material comprises a green phosphorescent dopant material or a red phosphorescent dopant material. 5. The method of claim 4,
Wherein a doping concentration of the first phosphorescent dopant material in the electron transport layer is 1 to 30 vol%.

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