Organic light-emitting devices

Abstract

The present invention provides an organic light-emitting device with low driving voltage, high luminous efficiency and suppressed gradual driving voltage rise by including a compound with a specific structure in a hole transport region.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority based on Korean Patent Application No. 10-2018-0135440 filed on November 6, 2018 and Korean Patent Application No. 10-2019-0139626 filed on November 4, 2019, and incorporates all the contents disclosed in the documents of the Korean patent applications as part of this specification.

[0003] The invention relates to an organic light emitting device with low driving voltage, high luminous efficiency and suppressed gradual driving voltage rise. Background Art

[0004] Generally speaking, the organic light-emitting phenomenon refers to the phenomenon of converting electrical energy into light energy using organic substances. Organic light-emitting devices using the organic light-emitting phenomenon have wide viewing angles, excellent contrast, fast response time, and excellent brightness, driving voltage, and response speed characteristics, so a lot of research is being carried out.

[0005] An organic light-emitting device generally has a structure including an anode and a cathode and an organic layer located between the anode and the cathode. In order to improve the efficiency and stability of the organic light-emitting device, the organic layer is usually formed by a multilayer structure composed of different substances, for example, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, etc. For such an organic light-emitting device structure, if a voltage is applied between the two electrodes, holes are injected from the anode into the organic layer, and electrons are injected from the cathode into the organic layer. When the injected holes and electrons meet, excitons are formed, and when the excitons re-transition to the ground state, light is emitted.

[0006] As for organic substances used for organic light-emitting devices as described above, development of new materials continues to be required.

[0007] Prior art literature

[0008] Patent Literature

[0009] (Patent Document 0001) Korean Patent Publication No. 10-2000-0051826 Summary of the invention

[0010] Technical issues

[0011] The invention relates to an organic light emitting device with low driving voltage, high luminous efficiency and suppressed gradual driving voltage rise.

[0012] Solution to the problem

[0013] In order to solve the above-mentioned problems, the present invention provides the following organic light-emitting device.

[0014] The organic light emitting device according to the present invention comprises:

[0015] anode;

[0016] a cathode disposed opposite to the anode;

[0017] A light-emitting layer disposed between the anode and the cathode;

[0018] A hole transport region disposed between the anode and the light-emitting layer; and

[0019] An electron transport region is provided between the light emitting layer and the cathode,

[0020] The hole transport region includes:

[0021] A first electron blocking layer including a compound represented by the following Chemical Formula 1 and a second electron blocking layer including a compound represented by the following Chemical Formula 2:

[0022] [Chemical formula 1]

[0023]

[0024] In the above chemical formula 1,

[0025] L1 to L3 are each independently a single bond; substituted or unsubstituted C 6-60 or a substituted or unsubstituted C containing any one or more heteroatoms selected from N, O and S 2-60 Heteroarylene,

[0026] Ar1 is substituted or unsubstituted C 6-60 Aryl; or a substituted or unsubstituted C containing any one or more heteroatoms selected from N, O and S 2-60 Heteroaryl,

[0027] R1 and R2 are each independently hydrogen; deuterium; halogen; cyano; nitro; substituted or unsubstituted C 1-60 Alkyl; substituted or unsubstituted C 1-60 Haloalkyl; substituted or unsubstituted C 1-60 Haloalkoxy; substituted or unsubstituted C 3-60 Cycloalkyl; substituted or unsubstituted C 2-60 Alkenyl; substituted or unsubstituted C 6-60 Aryl; or a substituted or unsubstituted C containing any one or more heteroatoms selected from N, O and S 2-60 Heteroaryl,

[0028] a and b are each an integer from 0 to 9,

[0029] When a and b are 2 or more, the structures in the brackets are the same or different.

[0030] [Chemical formula 2]

[0031]

[0032] In the above chemical formula 2,

[0033] L4 to L6 are each independently a single bond; substituted or unsubstituted C 6-60 or a substituted or unsubstituted C containing any one or more heteroatoms selected from N, O and S 2-60 Heteroarylene,

[0034] Ar2 and Ar3 are each independently substituted or unsubstituted C 6-60 Aryl; or a substituted or unsubstituted C containing any one or more heteroatoms selected from N, O and S 2-60 Heteroaryl,

[0035] R3 to R7 are each independently hydrogen; deuterium; halogen; cyano; nitro; substituted or unsubstituted C 1-60 Alkyl; substituted or unsubstituted C 1-60 Haloalkyl; substituted or unsubstituted C 1-60 Haloalkoxy; substituted or unsubstituted C 3-60 Cycloalkyl; substituted or unsubstituted C 2-60 Alkenyl; substituted or unsubstituted C 6-60 Aryl; or a substituted or unsubstituted C containing any one or more heteroatoms selected from N, O and S 2-60 Heteroaryl,

[0036] c is an integer from 0 to 5,

[0037] d, e and f are each an integer from 0 to 4,

[0038] g is an integer from 0 to 3.

[0039] When c to g are 2 or more, the structures in the brackets are the same or different.

[0040] Effects of the Invention

[0041] The organic light-emitting device comprises a first electron blocking layer and a second electron blocking layer each comprising a compound of a specific structure in a hole transport region, so that a gradual driving voltage rise is suppressed, and high luminous efficiency and low driving voltage characteristics can be exhibited. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1An example of an organic light emitting device composed of a substrate 10 , an anode 20 , a second electron blocking layer 31 , a first electron blocking layer 33 , a light emitting layer 40 , an electron transport layer 51 , and a cathode 60 is illustrated.

[0043] Figure 2 The diagram illustrates an example of an organic light-emitting device consisting of a substrate 10, an anode 20, a P-type carrier generating layer 35, a hole injection layer 37, a second electron blocking layer 31, a first electron blocking layer 33, a light-emitting layer 40, a hole blocking layer 53, an electron transport layer 51, an electron injection layer 55 and a cathode 60.

[0044] Figure 3 Graphs showing changes in driving voltage of the organic light-emitting devices of Example 1, Comparative Example 1, and Comparative Example 2 over time. DETAILED DESCRIPTION

[0045] In the following, the present invention will be described in more detail to help understanding the present invention.

[0046] In this manual, It represents the bond to other substituents.

[0047] In the present specification, the term "substituted or unsubstituted" refers to a group selected from deuterium; a halogen group; a cyano group; a nitro group; a hydroxyl group; a carbonyl group; an ester group; an imide group; an amino group; a phosphine oxide group; an alkoxy group; an aryloxy group; an alkylthio group ( Alkyl thioxy); arylthio ( Aryl thioxy); alkylsulfonyl ( Alkyl sulfoxy); arylsulfonyl ( The invention also includes the following: aryl sulfoxyl group, silyl group, boryl group, alkyl group, cycloalkyl group, alkenyl group, aryl group, aralkyl group, aralkenyl group, alkylaryl group, alkylamino group, aralkylamino group, heteroarylamino group, arylamino group, arylphosphino group, or substituted or unsubstituted with one or more substituents of heteroaryl group containing one or more N, O and S atoms, or substituted or unsubstituted with substituents formed by connecting two or more substituents among the substituents exemplified above. For example, "substituent formed by connecting two or more substituents" may be biphenyl group. That is, biphenyl group may be an aryl group, and may also be interpreted as a substituent formed by connecting two phenyl groups.

[0048] In the present specification, the number of carbon atoms in the carbonyl group is not particularly limited, but preferably the number of carbon atoms is 1 to 40. Specifically, the compound may have the following structure, but is not limited thereto.

[0049]

[0050] In the present specification, in the ester group, the oxygen of the ester group may be substituted by a linear, branched or cyclic alkyl group having 1 to 25 carbon atoms or an aryl group having 6 to 25 carbon atoms. Specifically, the compound may be of the following structural formula, but is not limited thereto.

[0051]

[0052] In the present specification, the number of carbon atoms in the imide group is not particularly limited, but preferably the number of carbon atoms is 1 to 25. Specifically, the compound may have the following structure, but is not limited thereto.

[0053]

[0054] In the present specification, specific examples of the silyl group include trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, vinyldimethylsilyl, propyldimethylsilyl, triphenylsilyl, diphenylsilyl, and phenylsilyl, but are not limited thereto.

[0055] In the present specification, specific examples of the boryl group include trimethylboryl, triethylboryl, tert-butyldimethylboryl, triphenylboryl, and phenylboryl, but are not limited thereto.

[0056] In the present specification, as examples of the halogen group, there are fluorine, chlorine, bromine or iodine.

[0057] In the present specification, the alkyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 1 to 40. According to one embodiment, the number of carbon atoms in the alkyl group is 1 to 20. According to another embodiment, the number of carbon atoms in the alkyl group is 1 to 10. According to another embodiment, the number of carbon atoms in the alkyl group is 1 to 6. Specific examples of the alkyl group include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n-heptyl, 1-methylhexyl, cyclopentylmethyl, cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 2-methylpentyl, 4-methylhexyl, and 5-methylhexyl, but are not limited thereto.

[0058] In the present specification, the alkenyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 2 to 40. According to one embodiment, the number of carbon atoms of the alkenyl group is 2 to 20. According to another embodiment, the number of carbon atoms of the alkenyl group is 2 to 10. According to another embodiment, the number of carbon atoms of the alkenyl group is 2 to 6. As specific examples, there are vinyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 3-methyl-1-butenyl, 1,3-butadienyl, allyl, 1-phenylvinyl-1-yl, 2-phenylvinyl-1-yl, 2,2-diphenylvinyl-1-yl, 2-phenyl-2-(naphthalene-1-yl)vinyl-1-yl, 2,2-bis(diphenyl-1-yl)vinyl-1-yl, stilbene, styryl, etc., but are not limited thereto.

[0059] In the present specification, the cycloalkyl group is not particularly limited, but is preferably a cycloalkyl group having 3 to 60 carbon atoms. According to one embodiment, the cycloalkyl group has 3 to 30 carbon atoms. According to another embodiment, the cycloalkyl group has 3 to 20 carbon atoms. According to another embodiment, the cycloalkyl group has 3 to 6 carbon atoms. Specifically, there are cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3,4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, cyclooctyl, etc., but are not limited thereto.

[0060] In the present specification, the aryl group is not particularly limited, but is preferably an aryl group having 6 to 60 carbon atoms, and may be a monocyclic aryl group or a polycyclic aryl group. According to one embodiment, the carbon number of the aryl group is 6 to 30. According to one embodiment, the carbon number of the aryl group is 6 to 20. As a monocyclic aryl group, the aryl group may be phenyl, biphenyl, terphenyl, etc., but is not limited thereto. As the polycyclic aryl group, the aryl group may be naphthyl, anthracenyl, phenanthrenyl, pyrenyl, peryl, yl, fluorenyl, etc., but are not limited to these.

[0061] In the present specification, the fluorenyl group may be substituted, and two substituents may be combined with each other to form a spiro structure. etc., but not limited thereto.

[0062] In the present specification, the heteroaryl group is a heteroaryl group containing one or more of O, N, Si and S as heteroatoms, and the number of carbon atoms is not particularly limited, but preferably the number of carbon atoms is 2 to 60. Examples of the heteroaryl group include thienyl, furyl, pyrrolyl, imidazolyl, thiazolyl, Azolyl, oxadiazolyl, triazolyl, pyridyl, bipyridyl, pyrimidyl, triazinyl, acridinyl, pyridazinyl, pyrazinyl, quinolyl, quinazolinyl, quinoxalinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolyl, indolyl, carbazolyl, benzo oxazolyl, benzimidazolyl, benzothiazolyl, benzocarbazolyl, benzothiophenyl, dibenzothiophenyl, benzofuranyl, phenanthroline, isothiophene oxazolyl, thiadiazolyl, phenothiazinyl and dibenzofuranyl, but are not limited thereto.

[0063] In this specification, the aryl group in aralkyl, aralkenyl, alkylaryl, and arylamine is the same as the example of the aryl group described above. In this specification, the alkyl group in aralkyl, alkylaryl, and alkylamine is the same as the example of the alkyl group described above. In this specification, the heteroaryl group in heteroarylamine can be applied to the above description of heteroaryl. In this specification, the alkenyl group in aralkenyl is the same as the example of the alkenyl group described above. In this specification, the arylene group is a divalent group, and the above description of aryl can be applied otherwise. In this specification, the heteroarylene group is a divalent group, and the above description of heteroaryl can be applied otherwise. In this specification, the hydrocarbon ring is not a monovalent group, but is formed by combining two substituents, and the above description of aryl or cycloalkyl can be applied otherwise. In this specification, the heterocycle is not a monovalent group, but is formed by combining two substituents, and the above description of heteroaryl can be applied otherwise.

[0064] In the case of organic light-emitting devices using conventional phosphorescent materials, a higher driving voltage than the initial driving voltage is required to achieve the same brightness when a constant current is continuously applied, so there has always been a problem of shortening the life of the device. Such a gradual increase in driving voltage is known to be caused by degradation due to charge accumulation in the interface between the light-emitting layer and its adjacent layer.

[0065] Therefore, in the present invention, the hole transport region between the anode and the light emitting layer includes both the first electron blocking layer and the second electron blocking layer each including a compound of a specific structure, thereby providing an organic light emitting device with suppressed gradual driving voltage rise.

[0066] Specifically, in the organic light-emitting device according to the present invention, the first electron blocking layer is configured to be in contact with the light-emitting layer, and the second electron blocking layer is configured to be in contact with the first electron blocking layer. At this time, the first electron blocking layer contains the compound represented by the chemical formula 1, which not only blocks the migration of electrons and suppresses triplet transitions, but also plays a role in smoothly injecting and transporting holes in the light-emitting layer to adjust the carrier balance in the light-emitting layer. In addition, the second electron blocking layer contains the compound represented by the chemical formula 2, which has a higher triplet energy level than the triplet energy level of the phosphorescent material, and plays a role in preventing the triplet excitons of the light-emitting layer from being unable to emit light and disappearing from the hole transport region. Therefore, the organic light-emitting device according to the present invention can prevent the accumulation of charges at the interface between the layers, thereby suppressing the gradual increase in driving voltage, thereby showing high efficiency and long life characteristics.

[0067] Hereinafter, the present invention will be described in detail according to each configuration.

[0068] Anode and cathode

[0069] As the above-mentioned anode material, in order to enable holes to be smoothly injected into the organic layer, a material with a large work function is preferably used. Specific examples of the above-mentioned anode material include metals such as vanadium, chromium, copper, zinc, gold, or their alloys; metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO); combinations of metals and oxides such as ZnO:Al or SnO2:Sb; conductive polymers such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDOT), polypyrrole, and polyaniline, but are not limited thereto.

[0070] In order to facilitate the injection of electrons into the organic layer, the cathode material is preferably a material with a small work function. Specific examples of the cathode material include metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or alloys thereof; multilayer structure materials such as LiF / Al or LiO2 / Al, etc., but are not limited thereto.

[0071] Hole transport region

[0072] The organic light-emitting device according to the present invention includes a hole transport region arranged between an anode and a light-emitting layer. In the case of an organic light-emitting device using a phosphorescent light-emitting material, since the light-emitting region in the light-emitting layer is usually inclined toward the hole transport region, in order to control the transition between triplet states and concentrate excitons in the light-emitting layer, it is necessary not only to control the triplet energy of the hole transport region, but also to control the ability of carriers to be transported and injected in the hole transport region. To this end, the hole transport region of the organic light-emitting device of the present invention includes a first electron blocking layer and a second electron blocking layer, and preferably, in addition to the first and second electron blocking layers, an additional organic layer is also included to constitute more than three organic layers.

[0073] (First electron blocking layer)

[0074] The first electron blocking layer is a layer disposed in contact with the light-emitting layer, and includes an amine compound substituted with phenanthrene having high aromaticity on both sides, i.e., a compound represented by Chemical Formula 1. The high aromaticity of the compound represented by Chemical Formula 1 improves charge mobility, and charges are not accumulated and flowed out at the interface between the first electron blocking layer and the light-emitting layer, thereby preventing interface degradation caused by accumulated charges.

[0075] Preferably, in the above Chemical Formula 1, L1 to L3 are each independently a single bond, a phenylene group or a naphthylene group.

[0076] More preferably, L1 and L2 are each independently a phenylene group, specifically a 1,2-phenylene group, a 1,3-phenylene group or a 1,4-phenylene group, and L3 is a single bond, or is selected from any one of the following groups:

[0077]

[0078] Preferably, Ar1 is phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, triphenylene, dibenzofuranyl, dibenzothienyl or fluorenyl,

[0079] Here, the dibenzofuranyl group, dibenzothienyl group and fluorenyl group are each unsubstituted or may be replaced by C 1-10 Alkyl or C 6-20 Aryl substitution.

[0080] Further preferably, Ar1 is any one selected from the following groups:

[0081]

[0082] In the above groups,

[0083] X1 is O, S or CZ2Z3,

[0084] Z1 to Z3 are each independently a methyl group or a phenyl group.

[0085] Most preferably, Z1 is phenyl, and Z2 and Z3 are both methyl or both are phenyl.

[0086] Preferably, R1 and R2 are hydrogen, and a and b representing the number of R1 and R2 are 0 or 1, respectively.

[0087] Preferably, the compound represented by the above Chemical Formula 1 is represented by any one of the following Chemical Formulas 1-1 to 1-3:

[0088] [Chemical formula 1-1]

[0089]

[0090] [Chemical formula 1-2]

[0091]

[0092] [Chemical formula 1-3]

[0093]

[0094] In the above chemical formulas 1-1 to 1-3,

[0095] The explanations of L1 to L3 and Ar1 are the same as those defined in the above Chemical Formula 1.

[0096] Representative examples of the compound represented by the above Chemical Formula 1 are shown below:

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107]

[0108]

[0109]

[0110]

[0111]

[0112]

[0113]

[0114]

[0115]

[0116]

[0117] (Second electron blocking layer)

[0118] The second electron blocking layer is a layer disposed between the anode and the first electron blocking layer, preferably in contact with the first electron blocking layer, and includes a compound represented by Chemical Formula 2. The compound represented by Chemical Formula 2 includes nitrogen atoms that contribute to aromaticity, thereby easily transferring holes to the light-emitting layer, and includes nitrogen atoms that do not contribute to aromaticity, thereby having a stable structure in which electrons cannot flow out through the first electron blocking layer. Thus, the voltage increase caused by interface degradation between the first electron blocking layer and the second electron blocking layer of the organic light-emitting device can be suppressed.

[0119] Preferably, in the above Chemical Formula 2, L4 to L6 are each independently a single bond, a phenylene group or a biphenylene group.

[0120] More preferably, L4 is a single bond or a phenylene group, and further preferably a single bond or a 1,4-phenylene group. L5 and L6 are each independently a single bond, a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, or a 4,4′-biphenylene group.

[0121] Preferably, Ar2 and Ar3 are each independently phenyl, biphenyl, terphenyl, naphthyl, dibenzofuranyl, dibenzothiophenyl, fluorenyl, carbazolyl or spiro[acridine-9,9'-fluoren],

[0122] Here, dibenzofuranyl, dibenzothienyl, fluorenyl and spiro[acridinyl-9,9'-fluorene] are each unsubstituted or may be replaced by C 1-10 Alkyl or C 6-20 Aryl substitution.

[0123] Further preferably, Ar2 and Ar3 are each independently selected from any one of the following groups:

[0124] In the above groups,

[0125] X2 is O, S or CZ5Z6,

[0126] Z4 to Z6 are each independently methyl or phenyl.

[0127] Most preferably, Z4 is phenyl, and Z5 and Z6 are both methyl or both are phenyl.

[0128] Preferably, R3 to R7 are hydrogen, and c to g representing the number of R3 to R7 are 0 or 1, respectively.

[0129] Preferably, the compound represented by the above Chemical Formula 2 is represented by the following Chemical Formula 2-1:

[0130] [Chemical formula 2-1]

[0131]

[0132] In the above chemical formula 2-1,

[0133] The explanations of L4 to L6, Ar2 and Ar3 are the same as those defined in the above Chemical Formula 2.

[0134] Representative examples of the compound represented by the above Chemical Formula 2 are shown below:

[0135]

[0136]

[0137]

[0138]

[0139]

[0140]

[0141] On the one hand, regarding the triplet energy of the compound represented by the above Chemical Formula 2 and the compound represented by the above Chemical Formula 1, the following Formula 1 is satisfied:

[0142] [Formula 1]

[0143] E T (EBL1) -E T (EBL2) >0.15eV

[0144] In the above formula 1,

[0145] E T (EBL1) is the triplet energy of the compound represented by the above Chemical Formula 1,

[0146] E T (EBL2) is the triplet energy of the compound represented by the above Chemical Formula 2.

[0147] Specifically, when the difference between the triplet energy of the compound represented by the above Chemical Formula 1 and the triplet energy of the compound represented by the above Chemical Formula 2 is less than 0.15 eV, or the triplet energy of the compound represented by the above Chemical Formula 2 is higher than the triplet energy of the compound represented by the above Chemical Formula 1, the first electron blocking layer including the compound represented by the above Chemical Formula 1 cannot play a role in preliminarily blocking non-luminescent high-energy triplet excitons flowing into the light-emitting layer, and such triplet excitons bring electrical loads to the compound represented by the above Chemical Formula 2, so the life of the organic light-emitting device may be reduced.

[0148] On the contrary, when the above formula 1 is satisfied, the above first electron blocking layer effectively blocks the non-luminescent high triplet energy excitons in the light-emitting layer, which can reduce the electrical load on other organic layers close to the anode, thereby inhibiting the aging of organic substances and improving the life of the device. In addition, the compound represented by chemical formula 2 in the above second electron blocking layer has a triplet energy level similar to that of the substances in other organic layers close to the anode, so that the high-energy triplet excitons that are not screened out in the above first blocking layer can be quickly migrated to the anode side, thereby preventing the reduction in life caused by non-luminescent triplet excitons.

[0149] Such triplet energy can be calculated using time-dependent density functional theory (TD-DFT). Specifically, density functional calculations use the commercial computing program "Gaussian09" package developed by Gaussian, using B3PW91 (Becke exchange and Perdew correlation-correlation functional) as a functional and 6-31G* as a basis set. Thus, the calculated value of triplet energy can be obtained for the optimal molecular structure determined by density functional theory.

[0150] In addition, the low temperature photoluminescence method was used to measure After obtaining the edge value, the triplet energy can be calculated using the following conversion formula.

[0151] [Conversion formula]

[0152] Triplet energy (eV) = 1239.85 / (λ 边 )

[0153] In the above conversion formula,

[0154] λ 边 When the phosphorescence spectrum is represented by the vertical axis representing phosphorescence intensity and the horizontal axis representing wavelength, a tangent line is drawn to the rise on the short-wavelength side of the phosphorescence spectrum, and the wavelength value of the intersection of the tangent line and the horizontal axis is expressed in nm.

[0155] (P-type carrier generation layer)

[0156] The organic light-emitting device according to the present invention further includes a P-type carrier generation layer (positive type-carrier generation layer; P-CGL) in the hole transport region. The above-mentioned "P-type carrier generation layer" refers to a layer that receives electrons from the organic layer on the cathode side and generates holes, thereby helping more holes to migrate to the light-emitting layer side. Since the organic light-emitting device according to the present invention includes the above-mentioned P-type carrier generation layer, the luminous efficiency of the device is increased and the driving voltage can be reduced. Preferably, the above-mentioned P-type carrier generation layer is arranged between the above-mentioned anode and the above-mentioned second electron blocking layer, and most preferably, it is arranged in contact with the above-mentioned anode.

[0157] Such a P-type carrier generation layer includes a p-doped substance and a hole injection substance. Here, the p-doped substance refers to a substance that makes the main substance have a p-semiconductor characteristic, and the p-semiconductor characteristic can be defined as the characteristic of injecting or transmitting holes at the HOMO (Highest occupied molecular orbital) energy level, that is, the characteristic of a substance in which the mobility of holes is greater than the mobility of electrons.

[0158] Preferably, the p-dopant is represented by the following chemical formula 5 or 6:

[0159] [Chemical formula 5]

[0160]

[0161] In the above chemical formula 5,

[0162] A1 to A3 are each independently unsubstituted, or are each independently selected from cyano, halogen and C1-10 The C 6-60 or a C containing any one or more heteroatoms selected from N, O and S 2-60 Heteroaryl,

[0163] [Chemical formula 6]

[0164]

[0165] In the above chemical formula 6,

[0166] A4 to A9 are each independently hydrogen; deuterium; halogen; cyano; nitro; amide; SO2(C 6-60 aryl); substituted or unsubstituted C 1-60 Alkyl; substituted or unsubstituted C 2-60 Alkenyl; substituted or unsubstituted C 6-60 Aryl; or a substituted or unsubstituted C containing any one or more heteroatoms selected from N, O and S 2-60 Heteroaryl.

[0167] Further preferably, in the above Chemical Formula 5, A1 to A3 are each independently phenyl, naphthyl, pyridyl, pyrazinyl, pyrimidinyl, quinolyl or isoquinolyl,

[0168] Here, A1 to A3 are unsubstituted or substituted with one or more cyano groups or halogen groups.

[0169] For example, the compound represented by the above Chemical Formula 5 can be represented by the following Chemical Formula 5-1:

[0170] [Chemical formula 5-1]

[0171]

[0172] In addition, preferably, in the above chemical formula 6, A4 to A9 are each independently cyano; nitro; SO2(C 6-10 Aryl); unsubstituted or substituted with one or more cyano or nitro C 6-10 Aryl; or C unsubstituted or substituted with one or more cyano or nitro 2-10 Alkenyl.

[0173] For example, the compound represented by the above Chemical Formula 6 may be represented by any one of the following Chemical Formulas 6-1 to 6-6:

[0174] [Chemical formula 6-1]

[0175]

[0176] [Chemical formula 6-2]

[0177]

[0178] [Chemical formula 6-3]

[0179]

[0180] [Chemical formula 6-4]

[0181]

[0182] [Chemical formula 6-5]

[0183]

[0184] [Chemical formula 6-6]

[0185]

[0186] Preferably, the P-type carrier generating layer contains less than 10 wt % of the p-dopant. When the p-dopant is contained within the above range, the luminous efficiency of the organic light-emitting device can be improved while the driving voltage can be reduced.

[0187] In addition, the hole injection material can generally use the following compounds: have the ability to transport holes for the hole injection layer, have the effect of injecting holes from the anode, have an excellent hole injection effect for the light-emitting layer or the light-emitting material, prevent the excitons generated in the light-emitting layer from migrating to the electron injection layer or the electron injection material, and have excellent thin film forming ability. Preferably, the HOMO (highest occupied molecular orbital) of the hole injection material is between the work function of the anode material and the HOMO of the surrounding organic layer.

[0188] Specific examples of the hole injection material include metal porphyrin, oligothiophene, aromatic amine organic matter, hexanitrile hexaazatriphenylene organic matter, quinacridone organic matter, perylene organic matter, anthraquinone, polyaniline and polythiophene conductive polymers, but are not limited to these.

[0189] (Hole Injection Layer)

[0190] The organic light-emitting device according to the present invention may further include a hole injection layer in the hole transport region for injecting holes from the electrode. Preferably, the hole injection layer is disposed between the P-type carrier generation layer and the second electron blocking layer, thereby injecting holes into the light-emitting layer while transporting holes generated from the P-type carrier generation layer.

[0191] The hole injection layer is composed of a hole injection substance. Preferably, the hole injection substance is the same as the hole injection substance contained in the P-type carrier generation layer.

[0192] Luminescent layer

[0193] The organic light-emitting device according to the present invention comprises a light-emitting layer comprising a phosphorescent light-emitting material. Preferably, the light-emitting layer comprises two or more host materials, and most preferably, comprises both a P-type host material and an N-type host material, so that a proper ratio of holes and electrons can be maintained in the entire light-emitting layer, whereby excitons emit light uniformly in the entire light-emitting layer, thereby improving the light-emitting efficiency and life of the organic light-emitting device.

[0194] Preferably, the light-emitting layer comprises a first host substance represented by the following chemical formula 3 and a second host substance represented by the following chemical formula 4:

[0195] [Chemical formula 3]

[0196]

[0197] In the above chemical formula 3,

[0198] Ar 11 and Ar 12 are each independently substituted or unsubstituted C 6-60 Aryl; or a substituted or unsubstituted C containing any one or more heteroatoms selected from N, O and S 2-60 Heteroaryl,

[0199] R 11 and R 12 are independently hydrogen; deuterium; halogen; cyano; nitro; substituted or unsubstituted C 1-60 Alkyl; substituted or unsubstituted C 1-60 Haloalkyl; substituted or unsubstituted C 1-60 Haloalkoxy; substituted or unsubstituted C 3-60 Cycloalkyl; substituted or unsubstituted C 2-60 Alkenyl; substituted or unsubstituted C 6-60 Aryl; or a substituted or unsubstituted C containing any one or more heteroatoms selected from N, O and S 2-60 Heteroaryl,

[0200] h and i are each an integer from 0 to 4,

[0201] [Chemical formula 4]

[0202]

[0203] In the above chemical formula 4,

[0204] Y is O or S,

[0205] Ar 13 is substituted or unsubstituted C 6-60 Aryl; or a substituted or unsubstituted C containing any one or more heteroatoms selected from N, O and S 2-60 Heteroaryl,

[0206] HAr is a substituted or unsubstituted C containing one or more nitrogen atoms. 2-60 Heteroaryl,

[0207] R 13 and R 14 are independently hydrogen; deuterium; halogen; cyano; nitro; substituted or unsubstituted C 1-60 Alkyl; substituted or unsubstituted C 1-60 Haloalkyl; substituted or unsubstituted C 1-60 Haloalkoxy; substituted or unsubstituted C 3-60 Cycloalkyl; substituted or unsubstituted C 2-60 Alkenyl; substituted or unsubstituted C 6-60 Aryl; or a substituted or unsubstituted C containing any one or more heteroatoms selected from N, O and S 2-60 Heteroaryl,

[0208] k and j are integers of 0 to 3, respectively.

[0209] For example, the light-emitting layer may include a compound represented by the following chemical formula 3-1 as a first host substance, and may include a compound represented by the following chemical formula 4-1 as a second host substance:

[0210] [Chemical formula 3-1]

[0211]

[0212] [Chemical formula 4-1]

[0213]

[0214] In addition, the light-emitting layer may further include a dopant material. Examples of the dopant material include aromatic amine derivatives, styrylamine compounds, boron complexes, fluoranthene compounds, metal complexes, and the like. Specifically, aromatic amine derivatives are aromatic fused ring derivatives having substituted or unsubstituted arylamino groups, such as pyrene, anthracene, , diindenopyrene, etc. The styrylamine compound is a compound in which at least one arylvinyl group is substituted in a substituted or unsubstituted arylamine, and is substituted or unsubstituted with one or more substituents selected from aryl, silyl, alkyl, cycloalkyl and arylamino. Specifically, there are styrylamine, styryldiamine, styryltriamine, styryltetramine, etc., but not limited thereto. In addition, as a metal complex, there are iridium complexes, platinum complexes, etc., but not limited thereto. Preferably, the above-mentioned light-emitting layer may contain an iridium complex as a dopant material.

[0215] The organic light-emitting device having the light-emitting layer including the above-mentioned host material and the dopant material can show the maximum wavelength (λ 最大 ). Therefore, the above-mentioned organic light-emitting device is a green light-emitting organic light-emitting device.

[0216] Electron transport region

[0217] The organic light-emitting device according to the present invention comprises an electron transport region arranged between the above-mentioned light-emitting layer and the cathode. The above-mentioned electron transport region, as a region for transporting electrons from the cathode to the light-emitting layer, generally comprises an electron transport layer. Preferably, the above-mentioned electron transport region comprises a hole blocking layer, an electron transport layer and an electron injection layer.

[0218] (Hole Blocking Layer)

[0219] The hole blocking layer is formed on the light-emitting layer. Specifically, the hole blocking layer is arranged in contact with the light-emitting layer and refers to a layer that improves the efficiency of the organic light-emitting device by preventing excessive migration of holes and increasing the probability of combination between holes and electrons.

[0220] The hole blocking layer contains a hole blocking substance. Examples of such a hole blocking substance include triazole derivatives, Oxadiazole derivatives, phenanthroline derivatives, etc., but are not limited to these.

[0221] (Electron Transport Layer)

[0222] The electron transport layer is formed between the light-emitting layer and the cathode, preferably between the hole blocking layer and the electron injection layer described below, and plays a role of receiving electrons from the electron injection layer and transporting the electrons to the light-emitting layer.

[0223] The electron transport layer contains an electron transport substance. Such an electron transport substance is a substance that can well receive electrons from the cathode and transfer them to the light-emitting layer. A substance having a high mobility for electrons is suitable.

[0224] As specific examples of the above-mentioned electron transport materials, there are pyridine derivatives, pyrimidine derivatives, triazole derivatives, Al complexes of 8-hydroxyquinoline, complexes containing Alq3, organic free radical compounds, hydroxyflavone-metal complexes, etc., but are not limited thereto. The electron transport layer can be used together with any desired cathode material as used in the prior art. In particular, examples of suitable cathode materials are common materials with low work function and accompanied by an aluminum layer or a silver layer. Specifically, cesium, barium, calcium, ytterbium and samarium, in each case accompanied by an aluminum layer or a silver layer.

[0225] (Electron Injection Layer)

[0226] The organic light-emitting device according to the present invention may further include an electron injection layer between the electron transport layer and the cathode. The electron injection layer is a layer that injects electrons from the electrode, and is preferably a compound that has the ability to transport electrons, has the effect of injecting electrons from the cathode, has an excellent electron injection effect for the light-emitting layer or method material, prevents the excitons generated in the light-emitting layer from migrating to the hole injection layer, and has excellent thin film forming ability.

[0227] Specific examples of the substance that can be used for the electron injection layer include LiF, NaCl, CsF, Li2O, BaO, fluorenone, anthraquinone dimethane, diphenoquinone, thiopyran dioxide, Azoles, Examples include, but are not limited to, diazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenylene methane, anthrone, and derivatives thereof, metal coordination compounds, and nitrogen-containing five-membered ring derivatives.

[0228] Examples of the metal coordination compounds include, but are not limited to, 8-hydroxyquinoline lithium, bis(8-hydroxyquinoline) zinc, bis(8-hydroxyquinoline) copper, bis(8-hydroxyquinoline) manganese, tris(8-hydroxyquinoline) aluminum, tris(2-methyl-8-hydroxyquinoline) aluminum, tris(8-hydroxyquinoline) gallium, bis(10-hydroxybenzo[h]quinoline) beryllium, bis(10-hydroxybenzo[h]quinoline) zinc, bis(2-methyl-8-quinoline) gallium chloride, bis(2-methyl-8-quinoline)(o-cresol) gallium, bis(2-methyl-8-quinoline)(1-naphthol) aluminum, and bis(2-methyl-8-quinoline)(2-naphthol) gallium.

[0229] Organic light-emitting devices

[0230] The structure of the organic light emitting device according to the present invention is shown in Figure 1 . Figure 1The diagram shows an example of an organic light-emitting device composed of a substrate 10, an anode 20, a hole transport region 30, a light-emitting layer 40, an electron transport region 50 and a cathode, wherein a second electron blocking layer 31 and a first electron blocking layer 33 are sequentially provided in the hole transport region 30, and an electron transport layer 51 is provided in the electron transport region 50. In the above structure, the compound represented by the chemical formula 1 may be contained in the first electron blocking layer 33, and the compound represented by the chemical formula 2 may be contained in the second electron blocking layer 31.

[0231] Figure 2 The diagram shows an example of an organic light-emitting device composed of a substrate 10, an anode 20, a hole transport region 30, a light-emitting layer 40, an electron transport region 50, and a cathode, wherein a P-type carrier generation layer 35, a hole injection layer 37, a second electron blocking layer 31, and a first electron blocking layer 33 are sequentially arranged in the hole transport region 30, and a hole blocking layer 53, an electron transport layer 51, and an electron injection layer 55 are sequentially arranged in the electron transport region 50. In the above structure, the compound represented by the above chemical formula 1 may be contained in the above first electron blocking layer 33, and the compound represented by the above chemical formula 2 may be contained in the above second electron blocking layer 31.

[0232] The organic light-emitting device according to the present invention can be manufactured by stacking the above-mentioned structures in sequence. In this case, it can be manufactured as follows: using PVD (physical vapor deposition) such as sputtering or electron beam evaporation (e-beam evaporation), a metal or a conductive metal oxide or their alloy is evaporated on a substrate to form an anode, and then the above-mentioned layers are formed on the anode, and then a substance that can be used as a cathode is evaporated thereon to manufacture. In addition to this method, an organic light-emitting device can also be manufactured by sequentially evaporating a cathode substance, an organic layer, and an anode substance on a substrate. In addition, not only a vacuum evaporation method can be used, but also a solution coating method can be used to form a main body and a dopant into a light-emitting layer. Here, the so-called solution coating method refers to spin coating, dip coating, blade coating, inkjet printing, screen printing, spraying, roller coating, etc., but is not limited to this.

[0233] In addition to these methods, an organic light-emitting device can be manufactured by sequentially depositing a cathode material, an organic layer, and an anode material on a substrate (WO2003 / 012890). However, the manufacturing method is not limited to this.

[0234] On the other hand, the organic light emitting device according to the present invention may be a top emission type, a bottom emission type, or a bi-directional emission type according to the materials used.

[0235] The production of the organic light-emitting device is specifically described in the following examples. However, the following examples are used to illustrate the present invention, and the scope of the present invention is not limited thereto.

[0236] Example

[0237] As the anode, ITO The deposited substrate was cut into a size of 50 mm × 50 mm × 0.5 mm and placed in distilled water dissolved with a dispersant, and washed with ultrasound. The detergent used was a product of Fischer Co., and the distilled water used was distilled water filtered twice using a filter manufactured by Millipore Co. After washing the ITO for 30 minutes, ultrasonic washing was repeated twice with distilled water for 10 minutes. After the distilled water washing was completed, ultrasonic washing was performed in sequence with solvents of isopropyl alcohol, acetone, and methanol and dried.

[0238] On the anode thus prepared, compound HIL1 and p-dopant (3 wt%) were added in the amount of A P-type carrier generating layer is formed by vacuum evaporation with a thickness of , and a compound HIL1 is deposited on the P-type carrier generating layer with a thickness of Then, on the hole injection layer, the following compound 2-1, 2-2 or 2-3 was deposited in a vacuum evaporation process to form a hole injection layer. A second electron blocking layer is formed by vacuum evaporation with a thickness of , and the following compound 1-1 is deposited on the second electron blocking layer. A first electron blocking layer is formed by vacuum deposition with a thickness of 1000 Å.

[0239] Then, on the first electron blocking layer, the first host (GH1) and the second host (GH2) were vacuum-deposited at a weight ratio of 6 to 4, and the dopant (GD) was vacuum-deposited at 6 weight %, thereby forming The thickness of the light-emitting layer.

[0240] Then, compound HBL1 was deposited on the light-emitting layer. The hole blocking layer was formed by vacuum evaporation at a thickness of 1000 mm / s. Then, the compound ETL1 and LiQ were respectively and The electron transport layer is formed by vacuum evaporation of a thickness of After forming a lithium fluoride (LiF) film of 1000 mm thickness as an electron injection layer, magnesium and silver (1:4) were mixed as the cathode. After the thickness is formed, CPL is evaporated Thus, the device is completed. In the above process, the evaporation rate of the organic matter is maintained at At this time, vacuum deposition of each layer was performed using a cluster type 1.0E-7 vacuum deposition machine (manufactured by Selcos).

[0241] Comparative Example 1

[0242] An organic light-emitting device was manufactured by the same method as in the above embodiment, except that the compound HTL1 was used as the second electron blocking layer material instead of the compound 2-1, and the compound EBL1 was used as the first electron blocking layer material instead of the compound 1-1.

[0243] Comparative Example 2

[0244] An organic light-emitting device was manufactured by the same method as in the above example, except that the compound EBL1 was used instead of the compound 1-1 as the first electron blocking layer material.

[0245] The compounds used in the above examples and comparative examples are shown below.

[0246]

[0247]

[0248]

[0249] Experimental Example 1

[0250] The voltage, efficiency and color coordinates when current was applied to the organic light-emitting devices manufactured in the above-mentioned Example, Comparative Example 1 and Comparative Example 2 were measured using PR-655IVL of Photo Research. The results are shown in Table 1 below. In addition, in order to confirm the gradual increase in driving voltage of the organic light-emitting devices manufactured in the above-mentioned Example, Comparative Example 1 and Comparative Example 2, the change in driving voltage according to the current application time was measured using M6000 of McScience Company, and the results are shown in Table 1. Figure 3 .

[0251]

Table 1

[0252]

[0253] As shown in Table 1 and Figure 3 As shown, the organic light-emitting device of the embodiment using the compound represented by Chemical Formula 1 and the compound represented by Chemical Formula 2 according to the present invention as the first electron blocking layer and the second electron blocking layer, respectively, not only exhibits excellent characteristics in voltage and efficiency compared with the organic light-emitting devices of Comparative Examples 1 and 2, but also has a significantly reduced gradual driving voltage rise amplitude.

[0254] Explanation of symbols

[0255] 10: substrate 20: anode

[0256] 30: hole transport region 31: second electron blocking layer

[0257] 33: First electron blocking layer 35: P-type carrier generation layer

[0258] 37: hole injection layer 40: light emitting layer

[0259] 50: electron transport region 51: electron transport layer

[0260] 53: hole blocking layer 55: electron injection layer

[0261] 60: Cathode

Claims

1. An organic light-emitting device, comprising: anode; a cathode disposed opposite to the anode; A light-emitting layer disposed between the anode and the cathode; a hole transport region disposed between the anode and the light-emitting layer; as well as An electron transport region is provided between the light-emitting layer and the cathode, The hole transport region comprises: A first electron blocking layer including a compound represented by the following Chemical Formula 1 and a second electron blocking layer including a compound represented by the following Chemical Formula 2: Chemical formula 1 In the chemical formula 1, L1 to L3 are each independently a single bond; or a deuterium-substituted or unsubstituted phenylene group, Ar1 is a deuterium-substituted or unsubstituted phenyl group, or a deuterium-substituted or unsubstituted biphenyl group, R1 and R2 are each independently hydrogen or deuterium, a and b are each an integer from 0 to 9, When a and b are 2 or more, the structures in the brackets are the same or different. Chemical formula 2 In the chemical formula 2, L4 is a single bond, L5 and L6 are each independently a single bond; or a deuterium-substituted or unsubstituted phenylene group, Ar2 and Ar3 are each independently a deuterium-substituted or unsubstituted phenyl group, or a deuterium-substituted or unsubstituted biphenyl group, R3 to R7 are each independently hydrogen or deuterium, c is an integer from 0 to 5, d, e and f are each an integer from 0 to 4, g is an integer from 0 to 3, When c to g are 2 or more, the structures in the brackets are the same or different.

2. The organic light emitting device according to claim 1, wherein: L1 to L3 are each independently a single bond or a phenylene group.

3. The organic light emitting device according to claim 1, wherein: Ar1 is any one selected from the following groups:

4. The organic light emitting device according to claim 1, wherein: The compound represented by the chemical formula 1 is represented by any one of the following chemical formulas 1-1 to 1-3: Chemical formula 1-1 Chemical formula 1-2 Chemical formula 1-3 In the chemical formulas 1-1 to 1-3, The explanations of L1 to L3 and Ar1 are the same as those defined in claim 1.

5. The organic light emitting device according to claim 1, wherein: The compound represented by the chemical formula 1 is any one selected from the following compounds:

6. The organic light emitting device according to claim 1, wherein: L5 and L6 are each independently a single bond or a phenylene group.

7. The organic light emitting device according to claim 1, wherein: Ar2 and Ar3 are each independently selected from any one of the following groups:

8. The organic light emitting device according to claim 1, wherein: The compound represented by the chemical formula 2 is represented by the following chemical formula 2-1: Chemical formula 2-1 In the chemical formula 2-1, The explanations of L4 to L6, Ar2 and Ar3 are the same as those defined in claim 1.

9. The organic light emitting device according to claim 1, wherein: The compound represented by the chemical formula 2 is any one selected from the following compounds:

10. The organic light emitting device according to claim 1, wherein: The compound represented by the chemical formula 1 and the compound represented by the chemical formula 2 satisfy the following formula 1: Formula 1 E T (EBL1) -E T (EBL2) >0.15eV In the formula 1, E T (EBL1) is the triplet energy of the compound represented by the chemical formula 1, E T (EBL2) is the triplet energy of the compound represented by the chemical formula 2.

11. The organic light emitting device according to claim 1, wherein: The first electron blocking layer is arranged in contact with the light emitting layer.

12. The organic light emitting device according to claim 1, wherein: The light-emitting layer contains two or more host substances.

13. The organic light emitting device according to claim 12, wherein: The light-emitting layer includes a host material represented by the following chemical formula 3 and a host material represented by the following chemical formula 4: Chemical formula 3 In the chemical formula 3, Ar 11 and Ar 12 are each independently substituted or unsubstituted C 6-60 Aryl; or a substituted or unsubstituted C containing any one or more heteroatoms selected from N, O and S 2-60 Heteroaryl, R 11 and R 12 are independently hydrogen; deuterium; halogen; cyano; nitro; substituted or unsubstituted C 1-60 Alkyl; substituted or unsubstituted C 1-60 Haloalkyl; substituted or unsubstituted C 1-60 Haloalkoxy; substituted or unsubstituted C 3-60 Cycloalkyl; substituted or unsubstituted C 2-60 Alkenyl; substituted or unsubstituted C 6-60 Aryl; or a substituted or unsubstituted C containing any one or more heteroatoms selected from N, O and S 2-60 Heteroaryl, h and i are each an integer from 0 to 4, Chemical formula 4 In the chemical formula 4, Y is O or S, Ar 13 is substituted or unsubstituted C 6-60 Aryl; or a substituted or unsubstituted C containing any one or more heteroatoms selected from N, O and S 2-60 Heteroaryl, HAr is a substituted or unsubstituted C containing one or more nitrogen atoms. 2-60 Heteroaryl, R 13 and R 14 are independently hydrogen; deuterium; halogen; cyano; nitro; substituted or unsubstituted C 1-60 Alkyl; substituted or unsubstituted C 1-60 Haloalkyl; substituted or unsubstituted C 1-60 Haloalkoxy; substituted or unsubstituted C 3-60 Cycloalkyl; substituted or unsubstituted C 2-60 Alkenyl; substituted or unsubstituted C 6-60 Aryl; or a substituted or unsubstituted C containing any one or more heteroatoms selected from N, O and S 2-60 Heteroaryl, k and j are integers of 0 to 3, respectively.

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