Patent Application
20230263054
The present disclosure relates to an organic light emitting device.
In general, an organic light emitting phenomenon refers to a phenomenon where electric energy is converted into light energy by using an organic material. The organic light emitting device using the organic light emitting phenomenon has characteristics such as a wide viewing angle, an excellent contrast, a fast response time, an excellent luminance, driving voltage and response speed, and thus many studies have proceeded.
The organic light emitting device generally has a structure which comprises an anode, a cathode, and an organic material layer interposed between the anode and the cathode. The organic material layer frequently has a multilayered structure that comprises different materials in order to enhance efficiency and stability of the organic light emitting device, and for example, the organic material layer can be formed of a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer and the like. In the structure of the organic light emitting device, if a voltage is applied between two electrodes, the holes are injected from an anode into the organic material layer and the electrons are injected from the cathode into the organic material layer, and when the injected holes and electrons meet each other, an exciton is formed, and light is emitted when the exciton falls to a ground state again.
There is a continuous need to develop new materials for organic materials used in the organic light emitting device as described above.
(Patent Literature 0001) Korean Unexamined Patent Publication No. 10-2000-0051826
It is an object of the present disclosure to provide an organic light emitting device.
According to the present disclosure, there is provided an organic light emitting device comprising:
an anode;
a cathode provided opposite to the anode; and
a light emitting layer provided between the anode and the cathode,
wherein the light emitting layer includes a first compound of the following Chemical Formula 1, a second compound of the following Chemical Formula 2 and a third compound of the following Chemical Formula 3:
wherein, in Chemical Formula 1:
A is a benzene ring fused with two adjacent pentagonal rings;
L1 and L2 are each independently a single bond or a substituted or unsubstituted C6-60 arylene;
Ar1 and Ar2 are each independently a substituted or unsubstituted C6-60 aryl, a substituted or unsubstituted dibenzofuranyl, a substituted or unsubstituted dibenzothiophenyl, or a substituted or unsubstituted carbazolyl;
R1 to R3 are each independently hydrogen, deuterium, or a C6-12 aryl;
a is an integer of 0 to 4;
b is an integer of 0 to 2; and
c is an integer of 0 to 4;
wherein, in Chemical Formula 2:
B is a benzene ring fused with two adjacent pentagonal rings;
Y′ is O, S, N(Ar13), or C(R14)(R15);
Z1 to Z3 are each independently N or CH, with the proviso that at least one of Z1 to Z3 is N;
L′ is a single bond, a substituted or unsubstituted C6-60 arylene, or a substituted or unsubstituted C2-60 heteroarylene containing at least one heteroatom selected among N, O and S;
Ar11 to Ar13 are each independently deuterium, a substituted or unsubstituted C6-60 aryl, or a substituted or unsubstituted C2-60 heteroaryl containing at least one heteroatom selected among N, O and S;
R11 to R13 are each independently hydrogen, deuterium, or a C6-12 aryl;
R14 and R15 are each independently hydrogen, deuterium, a C1-60 alkyl, or a C6-60 aryl;
d is an integer of 0 to 4;
e is an integer of 0 to 2; and
k is an integer of 0 to 4;
wherein, in Chemical Formula 3:
X1 to X3 are each independently N or CH, with the proviso that at least one of X1 to X3 is N;
Y is O or S;
L is a single bond, a substituted or unsubstituted C6-60 arylene, or a substituted or unsubstituted C2-60 heteroarylene containing at least one heteroatom selected among N, O and S;
Ar21 to Ar23 are each independently deuterium, a substituted or unsubstituted C6-60 aryl, or a substituted or unsubstituted C2-60 heteroaryl containing at least one heteroatom selected among N, O and S;
R21 is hydrogen, deuterium, or a C6-12 aryl;
f is an integer of 0 to 6; and
when a, b, c, d, e, f and k are each 2 or more, the substituents in parentheses are identical to or different from each other.
The above-mentioned organic light emitting device includes two types of host compounds in the light emitting layer, thereby capable of improving efficiency, driving voltage, and/or lifetime characteristics in the organic light emitting device.
Hereinafter, embodiments of the present disclosure will be described in more detail to assist in the understanding of the invention.
As used herein, the notation
means a bond linked to another substituent group, D means deuterium, and Ph means a phenyl group.
As used herein, the term “substituted or unsubstituted” means being unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, a halogen group, a nitrile group, a nitro group, a hydroxy group, a carbonyl group, an ester group, an imide group, an amino group, a phosphine oxide group, an alkoxy group, an aryloxy group, an alkylthioxy group, an arylthioxy group, an alkylsulfoxy group, an arylsulfoxy group, a silyl group, a boron group, an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, an aralkenyl group, an alkylaryl group, an alkylamine group, an aralkylamine group, a heteroarylamine group, an arylamine group, an arylphosphine group, or a heterocyclic group containing at least one of N, O and S atoms, or being unsubstituted or substituted with a substituent to which two or more substituents of the above-exemplified substituents are connected. For example, “a substituent in which two or more substituents are connected” can be a biphenyl group. Namely, a biphenyl group can be an aryl group, or it can also be interpreted as a substituent in which two phenyl groups are connected. In one example, the term “substituted or unsubstituted” as used herein can be understood as meaning “unsubstituted or substituted with one or more substituents, e.g., 1 to 5 substituents, selected from the group consisting of deuterium, halogen, cyano, a C1-10 alkyl, a C1-10 alkoxy and a C6-20 aryl. In addition, the term “substituted with one or more substituents” as used herein can be understood as meaning, for example, “substituted with 1 to 10 substituents”, “substituted with 1 to 5 substituents”, or “substituted with 1 or 2 substituents”.
In the present disclosure, the carbon number of a carbonyl group is not particularly limited, but is preferably 1 to 40. Specifically, the carbonyl group can be a substituent having the following structural formulas, but is not limited thereto:
In the present disclosure, an ester group can have a structure in which oxygen of the ester group can be substituted by a straight-chain, branched, or cyclic alkyl group having 1 to 25 carbon atoms, or an aryl group having 6 to 25 carbon atoms. Specifically, the ester group can be a substituent having the following structural formulas, but is not limited thereto:
In the present disclosure, the carbon number of an imide group is not particularly limited, but is preferably 1 to 25. Specifically, the imide group can be a substituent having the following structural formulas, but is not limited thereto:
In the present disclosure, a silyl group specifically includes a trimethylsilyl group, a triethylsilyl group, a t-butyldimethylsilyl group, a vinyldimethylsilyl group, a propyldimethylsilyl group, a triphenylsilyl group, a diphenylsilyl group, a phenylsilyl group and the like, but is not limited thereto.
In the present disclosure, a boron group specifically includes a trimethylboron group, a triethylboron group, a t-butyldimethylboron group, a triphenylboron group, and a phenylboron group, but is not limited thereto.
In the present disclosure, examples of a halogen group include fluorine, chlorine, bromine, or iodine.
In the present disclosure, the alkyl group can be straight-chain or branched-chain, and the carbon number thereof is not particularly limited, but is preferably 1 to 40. According to one embodiment, the carbon number of the alkyl group is 1 to 20. According to another embodiment, the carbon number of the alkyl group is 1 to 10. According to one embodiment, 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-ethylbutyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, 1-ethyl-propyl, 1,1,-dimethylpropyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n-heptyl, isohexyl, 1-methylhexyl, 2-methylhexyl, 3-methylhexyl, 4-methylhexyl, 5-methylhexyl, cyclopentylmethyl, cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2,4,4-trimethyl-1-pentyl, 2,4,4-trimethyl-2-pentyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, and the like, but are not limited thereto.
In the present disclosure, the alkenyl group can be straight-chain or branched-chain, and the carbon number thereof is not particularly limited, but is preferably 2 to 40. According to one embodiment, the carbon number of the alkenyl group is 2 to 20. According to another embodiment, the carbon number of the alkenyl group is 2 to 10. According to still another embodiment, the carbon number of the alkenyl group is 2 to 6. Specific examples thereof include 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-(naphthyl-1-yl)vinyl-1-yl, 2,2-bis(diphenyl-1-yl)vinyl-1-yl, a stilbenyl group, a styrenyl group, and the like, but are not limited thereto.
In the present disclosure, a cycloalkyl group is not particularly limited, but the carbon number thereof is preferably 3 to 60. According to one embodiment, the carbon number of the cycloalkyl group is 3 to 30. According to another embodiment, the carbon number of the cycloalkyl group is 3 to 20. According to still another embodiment, the carbon number of the cycloalkyl group is 3 to 6. Specific examples thereof include 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, adamantyl, and the like, but are not limited thereto.
In the present disclosure, an aryl group is not particularly limited, but the carbon number thereof is preferably 6 to 60, and it can 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. The aryl group can be a phenyl group, a biphenyl group, a terphenyl group or the like as the monocyclic aryl group, but is not limited thereto. The polycyclic aryl group includes a naphthyl group, an anthracenyl group, a phenanthryl group, a pyrenyl group, a perylenyl group, a chrysenyl group, a fluorenyl group, and the like, but is not limited thereto.
In the present disclosure, the fluorenyl group can be substituted, and two substituents can be linked with each other to form a spiro structure. In the case where the fluorenyl group is substituted,
and the like can be formed. However, the structure is not limited thereto.
In the present disclosure, a heteroaryl group is a heterocyclic group containing one or more of O, N, Si and S as a heteroatom, and the carbon number thereof is not particularly limited, but is preferably 2 to 60. Examples of the heteroaryl group include a thiophene group, a furan group, a pyrrole group, an imidazole group, a thiazole group, an oxazol group, an oxadiazol group, a triazol group, a pyridyl group, a bipyridyl group, a pyrimidyl group, a triazine group, an acridyl group, a pyridazine group, a pyrazinyl group, a quinolinyl group, a quinazoline group, a quinoxalinyl group, a phthalazinyl group, a pyridopyrimidinyl group, a pyridopyrazinyl group, a pyrazinopyrazinyl group, an isoquinoline group, an indole group, a carbazole group, a benzoxazole group, a benzoimidazole group, a benzothiazol group, a benzocarbazole group, a benzothiophene group, a dibenzothiophene group, a benzofuranyl group, a phenanthroline group, an isoxazolyl group, a thiadiazolyl group, a phenothiazinyl group, a dibenzofuranyl group, and the like, but are not limited thereto.
In the present disclosure, the aryl group in the aralkyl group, the aralkenyl group, the alkylaryl group, the arylamine group and the arylsilyl group is the same as the aforementioned examples of the aryl group. In the present disclosure, the alkyl group in the aralkyl group, the alkylaryl group and the alkylamine group is the same as the aforementioned examples of the alkyl group. In the present disclosure, the heteroaryl in the heteroarylamine can be applied to the aforementioned description of the heteroaryl. In the present disclosure, the alkenyl group in the aralkenyl group is the same as the aforementioned examples of the alkenyl group. In the present disclosure, the aforementioned description of the aryl group can be applied except that the arylene is a divalent group. In the present disclosure, the aforementioned description of the heteroaryl group can be applied except that the heteroarylene is a divalent group. In the present disclosure, the aforementioned description of the aryl group or cycloalkyl group can be applied except that the hydrocarbon ring is not a monovalent group but formed by combining two substituent groups. In the present disclosure, the aforementioned description of the heteroaryl can be applied, except that the heterocyclic ring is not a monovalent group but formed by combining two substituent groups.
In the present disclosure, the term “deuterated or substituted with deuterium” means that at least one usable hydrogen in each chemical formula is replaced by deuterium. Specifically, in the definition of each chemical formula or substituent, being substituted with deuterium means that at least one or more positions at which hydrogen can be bonded in a molecule are replaced by deuterium. More specifically, it means that at least 10% of the usable hydrogen is replaced by deuterium. In one example, it means being at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or 100% deuterated in each chemical formula.
On the other hand, an organic light emitting device according to an embodiment includes an anode; a cathode provided opposite to the anode; and a light emitting layer provided between the anode and the cathode, wherein the light emitting layer includes a first compound of Chemical Formula 1, a second compound of Chemical Formula 2, and a third compound of Chemical Formula 3 as a host material of the light emitting layer.
The above-mentioned organic light emitting device according to the present disclosure simultaneously includes, as a host material, three types of compounds having a specific structure in the light emitting layer, thereby capable of improving efficiency, driving voltage, and/or lifetime characteristics in the organic light emitting device.
Hereinafter, the present disclosure will be described in detail for each configuration.
As the anode material, generally, a material having a large work function is preferably used so that holes can be smoothly injected into the organic material layer. Specific examples of the anode material include metals such as vanadium, chrome, copper, zinc, and gold, or an alloy thereof; metal oxides such as zinc oxides, indium oxides, indium tin oxides (ITO), and indium zinc oxides (IZO); a combination 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, and the like, but are not limited thereto.
As the cathode material, generally, a material having a small work function is preferably used so that electrons can be easily injected into the organic material layer. 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 an alloy thereof; a multilayered structure material such as LiF/Al or LiO2/Al, and the like, but are not limited thereto.
The organic light emitting device according to the present disclosure can include a hole injection layer between an anode and a hole transport layer described hereinafter, if necessary.
The hole injection layer is a layer that is located on the anode and injects holes from the anode, which includes a hole injection material. The hole injection material is preferably a compound which has a capability of transporting the holes, a hole injection effect in the anode and an excellent hole injection effect to the light emitting layer or the light emitting material, prevents movement of an exciton generated in the light emitting layer to the electron injection layer or the electron injection material, and has an excellent thin film forming ability. In particular, it is suitable that a HOMO (highest occupied molecular orbital) of the hole injection material is between the work function of the anode material and a HOMO of a peripheral organic material layer.
Specific examples of the hole injection material include metal porphyrine, oligothiophene, an arylamine-based organic material, a hexanitrilehexaazatriphenylene-based organic material, a quinacridone-based organic material, a perylene-based organic material, anthraquinone, polyaniline and polythiophene-based conductive polymer, and the like, but are not limited thereto.
The organic light emitting device according to the present disclosure can include a hole transport layer between the anode and the light emitting layer. The hole transport layer is a layer that receives holes from an anode or a hole injection layer formed on the anode and transports the holes to the light emitting layer, which includes a hole transport material. The hole transport material is suitably a material having large mobility to the holes, which can receive holes from the anode or the hole injection layer and transfer the holes to the light emitting layer. Specific examples thereof can include an arylamine-based organic material, a conductive polymer, a block copolymer in which a conjugate portion and a non-conjugate portion are present together, and the like, but are not limited thereto.
The organic light emitting device according to the present disclosure can include an electron blocking layer between the hole transport layer and the light emitting layer, if necessary. The electron blocking layer refers to a layer which is formed on the hole transport layer, preferably provided in contact with the light emitting layer, and serves to adjust the hole mobility, prevent excessive movement of electrons, and increase the probability of hole-electron coupling, thereby improving the efficiency of the organic light emitting device. The electron blocking layer includes an electron blocking material, and examples of such electron blocking material can include an arylamine-based organic material of the like, but is not limited thereto.
The organic light emitting device according to the present disclosure can include a light emitting layer between an anode and a cathode, and the light emitting layer includes the first compound, the second compound and the third compound as a host material Specifically, the first compound can function as a P-type host material in which a hole transport capability is superior to an electron transport capability, and the second compound and the third compound can function as an N-type host material in which an electron transport capability is superior to a hole transport capability, and can properly maintain the ratio of holes to electrons in the light emitting layer. In particular, when the two types of compounds are used in combination as the N-type host material in this way, it can exhibit low voltage and long lifetime device characteristics, as compared to the case where only one type of compound is used. In addition, the device employing the above three types of host materials can exhibit high efficiency and longer lifetime characteristics as compared to a device employing a combination between other compounds.
Hereinafter, the first compound, the second compound, and the third compound will be sequentially described.
The first compound is a compound of Chemical Formula 1. Specifically, the first compound is an indolocarbazole compound, and the compound has an excellent capability of transporting holes as a dopant material, thereby capable of increasing the recombination probability of holes and electrons in the light emitting layer together with a third compound described hereinafter which has excellent electron transport capability.
The first compound can be any one of the following Chemical Formulas 1-1 to 1-5, based on the fusion position of A:
wherein, in Chemical Formulas 1-1 to 1-5,
L1, L2, Ar1, Ar2, R1 to R3, a, b and c are as defined in Chemical Formula 1
Further, in Chemical Formula 1, L1 and L2 can be each independently a single bond; or a C6-20 arylene that is unsubstituted or substituted with deuterium.
Specifically, L1 and L2 can be each independently a single bond, or phenylene.
More specifically, L1 and L2 can be each independently a single bond, 1,2-phenylene, 1,3-phenylene, or 1,4-phenylene. For example, both L1 and L2 are a single bond; or one of L1 and L2 can be a single bond, and the other one can be 1,3-phenylene or 1,4-phenylene.
Further, Ar1 and Ar2 can be each independently a C6-20 aryl that is unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, a C1-10 alkyl and a C6-20 aryl; or a C2-20 heteroaryl containing one heteroatom of N O and S and that is unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, a C1-10 alkyl and a C6-20 aryl,
Specifically, both Ar1 and Ar2 can be a C6-20 aryl that is unsubstituted or substituted with 1 or 2 substituents selected from the group consisting of deuterium and a C1-10 alkyl; or one of Ar1 and Ar2 is a C6-20 aryl that is unsubstituted or substituted with 1 or 2 substituents selected from the group consisting of deuterium and C1-10 alkyl, and the other one can be a C2-20 heteroaryl containing one heteroatom of N, O and S and that is unsubstituted or substituted with deuterium.
More specifically, Ar1 and Ar2 are each independently phenyl, biphenylyl, terphenylyl, naphthyl, fluorenyl, dibenzofuranyl, dibenzothiophenyl, or carbazolyl,
wherein Ar1 and Ar2 are unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, a C1-10 alkyl and a C6-20 aryl.
In other words, Ar1 and Ar2 may not include a 6-membered heterocyclic ring containing a heteroatom N.
For example, Ar1 and Ar2 can be any one selected from the group consisting of the following, but are not limited thereto:
in this case, Ar1 and Ar2 can be identical to or different from each other.
Further, all of R1 to R3 can be hydrogen; or all can be deuterium.
At this time, a, which means the number of R1, is 0, 1, 2, 3, or 4, b, meaning the number of R2, is 0, 1, or 2, and c, which means the number of R3, is 0, 1, 2, 3, or 4.
Representative examples of the first compound of Chemical Formula 1 are as follows:
Meanwhile, the first compound can be prepared, for example, by a preparation method as shown in the following Reaction Scheme 1:
wherein in Reaction Scheme 1, each X can be independently halogen, preferably bromo, or chloro, and the definitions of other substituents are the same as described above.
Specifically, the compound of Chemical Formula 1 is prepared by coupling the starting materials SM1 and SM2 through an amine substitution reaction. The amine substitution reaction is preferably carried out in the presence of a palladium catalyst and a base. Further, a reactive group for the amine substitution reaction can be appropriately modified, and the method for preparing the compound of Chemical Formula 1 can be further embodied in Preparation Examples described hereinafter.
The second compound is an indolocarbazole-based (Y′═N(Ar13))/benzofurocarbazole-based (Y′═O)/benzothienocarbazole-based (Y′═S)/indenocarbazole-based (Y′═C(R14)(R15)) compound of Chemical Formula 2. Unlike the first compound, the second compound has a structure in which an N-containing 6-membered heterocyclic ring is essentially substituted at the N atom of the carbazole ring, and can serve as an N-type host to efficiently transfer electrons in the light emitting layer. Thereby, it is possible to increase hole-electron recombination probability in the light emitting layer together with a first compound described hereinafter which has excellent hole transport capability,
The second compound can be any one of the following Chemical Formulas 2-1 to 2-6, based on the fusion position of B:
wherein, in Chemical Formulas 2-1 to 2-6:
Y′, Z1 to Z3, L′, Ar11, Ar12, R11 to R13, d, e and k are as defined in Chemical Formula 2.
In this case, in Chemical Formula 2, Y′ is O, S, N(Ar13), or C(R14)(R15),
wherein Ar13 is phenyl that is unsubstituted or substituted with deuterium; biphenylyl that is unsubstituted or substituted with deuterium; or terphenylyl that is unsubstituted or substituted with deuterium, and
R14 and R15 are each independently methyl or phenyl that is unsubstituted or substituted with deuterium.
For example, Ar13 can be any one selected from the group consisting of the following:
Further, for example, R14 and R15 can be identical to each other, and both R14 and R15 can be methyl, or both can be phenyl.
Further, all of Z1 to Z3 are N; or
Z1 and Z2 are N, and Z3 is CH; or
Z1 and Z3 are N, and Z2 is CH; or
Z1 is N, and Z2 and Z3 is CH; or
Z3 is N, and Z1 and Z2 are CH.
Further, L′ can be a single bond, or phenylene that is unsubstituted or substituted with deuterium.
For example, L′ can be a single bond, or any one selected from the group consisting of the following:
Further, Ar11 and Ar12 can be each independently a C6-20 aryl that is unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, a C1-10 alkyl and a C6-20 aryl that is unsubstituted or substituted with deuterium; or a C2-20 heteroaryl containing one heteroatom of N, O and S and that is unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, a C1-10 alkyl and a C6-20 aryl that is unsubstituted or substituted with deuterium.
More specifically, Ar11 and Ar12 can be each independently phenyl, biphenylyl, terphenylyl, naphthyl, fluorenyl, dibenzofuranyl, dibenzothiophenyl, or carbazolyl;
wherein Ar11 and Ar12 can be unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, a C1-10 alkyl and a C6-20 aryl that is unsubstituted or substituted with deuterium.
In other words, Ar11 and Ar12 may not include a 6-membered heterocyclic ring containing a heteroatom N.
For example, Ar11 and Ar12 can be any one selected from the group consisting of the following, but are not limited thereto:
wherein,
D is deuterium,
each m1 is independently an integer of 0 to 5,
each m2 is independently an integer of 0 to 4,
each m3 is independently an integer of 0 to 7,
each m4 is independently an integer from 0 to 3, and
each m5 is independently an integer of 0 to 8.
In addition, Ar11 and Ar12 can be identical to or different from each other.
Further, in Chemical Formula 2, R11 to R13 can be each independently hydrogen or deuterium.
In this case, d, which means the number of R11, is 0, 1, 2, 3, or 4, e, which means the number of R12, is 0, 1, or 2, and k, which means the number of R13, is 0, 1, 2, 3, or 4.
Further, d+e+k can be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.
Representative examples of the second compound of Chemical Formula 2 are as follows:
Meanwhile, the compound of Chemical Formula 2 can be prepared, for example, by a preparation method as shown in the following Reaction Scheme 2
wherein in Reaction Scheme 2, each X can be independently halogen, preferably bromo, or chloro, and the definitions of other substituents are the same as described above.
Specifically, the compound of Chemical Formula 2 is prepared by coupling the starting materials SM3 and SM4 through an amine substitution reaction. The amine substitution reaction is preferably carried out in the presence of a palladium catalyst and a base. Further, a reactive group for the amine substitution reaction can be appropriately modified, and the method for preparing the compound of Chemical Formula 2 can be further embodied in Preparation Examples described hereinafter.
(Third Compound)
The third compound has a structure in which one benzene ring of the dibenzofuran/dibenzothiophene core is substituted with an N-containing 6-membered heterocyclic ring and the other benzene ring is substituted with one aryl/heteroaryl group. As compared with a) a compound in which one benzene ring of the dibenzofuran/dibenzothiophene core is substituted with a 6-membered N-containing heterocycle, but the other benzene ring has no substituent other than deuterium, and b) a compound in which an N-containing 6-membered heterocycle and an aryl/heteroaryl group are simultaneously substituted in one benzene ring of the dibenzofuran/dibenzothiophene core, the third compound has excellent electron transport capability, and efficiently transfers electrons as a dopant material, so that electron-hole recombination probability in the light emitting layer can be increased.
In Chemical Formula 3, all of X1 to X3 are N, or two of X1 to X3 can be N, and the other one can be CH.
Further, L can be a single bond.
Further, Ar21 can be a C6-20 aryl that is unsubstituted or substituted with deuterium.
Alternatively, Ar21 can be a C2-20 heteroaryl containing a heteroatom O or S and that is unsubstituted or substituted with deuterium.
Alternatively, Ar21 can be a C2-20 heteroaryl containing one or two heteroatoms N and that is unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, phenyl and deuterium-substituted phenyl.
Specifically, Ar21 can be any one substituent of the following Chemical Formulas 4a to 4t:
wherein, in Chemical Formulas 4a to 4t:
D is deuterium;
each n1 is independently an integer of 0 to 5;
each n2 is independently an integer of 0 to 4;
each n3 is independently an integer of 0 to 7;
each n4 is independently an integer from 0 to 9;
each n5 is independently an integer of 0 to 3;
each n6 is independently an integer of 0 to 8;
each n7 is independently an integer of 0 to 10; and
each n8 is independently an integer of 0 to 6.
in one embodiment, n1 is 0 or 5,
n6 is 0, 4, 6 or 8, and
n7 can be 0 or 6,
Further, when Ar21 is a C6-20 aryl that is unsubstituted or substituted with deuterium, Ar21 can be any one of Chemical Formulas 4a to 4j.
Further, when Ar21 is a C2-20 heteroaryl containing a heteroatom O or S and that is unsubstituted or substituted with deuterium, Ar21 can be Chemical Formula 4s or 4t.
Further, when Ar21 is a C2-20 heteroaryl containing 1 or 2 heteroatoms N and that is unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, phenyl and deuterium-substituted phenyl, Ar21 can be any one of Chemical Formulas 4k to 4r.
Further, Ar22 and Ar23 can be each independently a C6-20 aryl that is unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, a C1-10 alkyl and a deuterium-substituted C6-20 aryl; or a C2-20 heteroaryl containing one heteroatom of N, O and S and that is unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, a C1-10 alkyl and a C6-20 aryl that is unsubstituted or substituted with deuterium,
Specifically, Ar22 and Ar23 are each independently phenyl, biphenylyl, terphenylyl, naphthyl, fluorenyl, dibenzofuranyl, dibenzothiophenyl, or carbazolyl;
wherein Ar22 and Ar23 can be unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, a C1-10 alkyl, and a C6-20 aryl that is unsubstituted or substituted with deuterium, for example, one or more substituents selected from the group consisting of deuterium, methyl, phenyl and deuterium-substituted phenyl.
More specifically, Ar22 and Ar23 can each independently be any one selected from the group consisting of the following, but are not limited thereto:
In one embodiment, at least one of Ar22 and Ar23 can be
Further, Ar22 and Ar23 can be identical to or different from each other.
Further, in Chemical Formula 3, f, each representing the number of R21, can be 0, 1, 2, 3, 4, 5, or 6.
Further, R21 can be deuterium, wherein when f is 0, at least one of Ar21 to Ar23 can be substituted with deuterium.
Meanwhile, the third compound can be a compound of the following Chemical Formula 3-1:
wherein, in Chemical Formula 3-1:
all of X1 to X3 are N, or two of X1 to X3 are N, and the other one is CH;
Ar21 is a C6-20 aryl that is unsubstituted or substituted with deuterium; a C2-20 heteroaryl containing a heteroatom O or S and that is unsubstituted or substituted with deuterium; or a C2-20 heteroaryl containing 1 or 2 heteroatoms N and that is unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, phenyl and deuterium-substituted phenyl;
Ar22 and Ar23 are each independently phenyl that is unsubstituted or substituted with deuterium; biphenylyl that is unsubstituted or substituted with deuterium; dibenzofuranyl that is unsubstituted or substituted with deuterium, dibenzothiophenyl that is unsubstituted or substituted with deuterium, or carbazolyl that is unsubstituted or substituted with deuterium, phenyl or deuterium-substituted phenyl;
R21 is deuterium; and
Y, L and f are as defined in Chemical Formula 3,
with the proviso that when f is 0, at least one of Ar21 to Ar23 is substituted with deuterium.
The compound of Chemical Formula can include at least one deuterium. For example, when R21 is deuterium and f is 0, at least one of Ar21 to Ar23 can be substituted with deuterium.
More specifically, the compound of Chemical Formula 3-1 can be a compound of the following Chemical Formula 3-1-1:
wherein, in Chemical Formula 3-1-1:
R′21 is hydrogen or deuterium;
X1 to X3, Ar21 to Ar23, Y, L, R21 and f are as defined in Chemical Formula 3-1,
Alternatively, the third compound can be a compound of the following Chemical Formula 3-2:
wherein, in Chemical Formula 3-2:
all of X1 to X3 are N, or two of X1 to X3 are N, and the other one is CH;
Ar21 is a C6-20 aryl that is unsubstituted or substituted with deuterium; a C2-20 heteroaryl containing a heteroatom O or S that is unsubstituted or substituted with deuterium; or a C2-20 heteroaryl containing 1 or 2 heteroatoms N and that is unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, phenyl and deuterium-substituted phenyl;
Ar22 and Ar23 are each independently phenyl that is unsubstituted or substituted with deuterium; biphenylyl that is unsubstituted or substituted with deuterium; dibenzofuranyl that is unsubstituted or substituted with deuterium, dibenzothiophenyl that is unsubstituted or substituted with deuterium, or carbazolyl that is unsubstituted or substituted with deuterium, phenyl or deuterium-substituted phenyl,
with the proviso that when one of Ar22 and Ar23 is dibenzofuranyl, the other one is not dibenzofuranyl and dibenzothiophenyl, and when one of Ar22 and Ar23 is dibenzothiophenyl, the other one is not dibenzofuranyl and dibenzothiophenyl, and
Y, L, R21 and f are as defined in Chemical Formula 3.
The compound of Chemical Formula 3-2 can include at least one deuterium. For example, when R21 is deuterium and f is 0, at least one of Ar21 to Ar23 can be substituted with deuterium.
Alternatively, the third compound can be a compound of the following Chemical Formula 3-3:
wherein, in Chemical Formula 3-3:
all of X1 to X3 are N, or two of X1 to X3 are N, and the other one is CH;
Ar21 is a C6-20 aryl that is unsubstituted or substituted with deuterium; a C2-20 heteroaryl containing a heteroatom O or S that is unsubstituted or substituted with deuterium; or a C2-20 heteroaryl containing 1 or 2 heteroatoms N and that is unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, phenyl and deuterium-substituted phenyl;
Ar22 and Ar23 are each independently phenyl that is unsubstituted or substituted with deuterium; biphenylyl that is unsubstituted or substituted with deuterium; dibenzofuranyl that is unsubstituted or substituted with deuterium, dibenzothiophenyl that is unsubstituted or substituted with deuterium, or carbazolyl that is unsubstituted or substituted with deuterium, phenyl or deuterium-substituted phenyl; and
Y, L, R21 and f are as defined in Chemical Formula 3.
The compound of Chemical Formula 3-3 can include at least one deuterium. For example, when R21 is deuterium and f is 0, at least one of Ar21 to Ar23 can be substituted with deuterium.
Alternatively, the third compound can be a compound of the following Chemical Formula 3-4:
wherein, in Chemical Formula 3-4:
all of X1 to X3 are N, or two of X1 to X3 are N, and the other one is CH;
Ar21 is a C6-20 aryl that is unsubstituted or substituted with deuterium; a C2-20 heteroaryl containing heteroatoms O or S and that is unsubstituted or substituted with deuterium; or a C2-20 heteroaryl containing 1 or 2 heteroatoms N and that is unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, phenyl and deuterium-substituted phenyl;
Ar22 and Ar23 are each independently phenyl that is unsubstituted or substituted with deuterium; biphenylyl that is unsubstituted or substituted with deuterium; dibenzofuranyl that is unsubstituted or substituted with deuterium, dibenzothiophenyl that is unsubstituted or substituted with deuterium, or carbazolyl that is unsubstituted or substituted with deuterium; and
Y, L, R21 and f are as defined in Chemical Formula 3.
The compound of Chemical Formula 3-4 can include at least one deuterium. For example, when R21 is deuterium and f is 0, at least one of Ar21 to Ar23 can be substituted with deuterium.
Representative examples of the third compound of Chemical Formula 3 are as follows:
Meanwhile, the compound of Chemical Formula 3 can be prepared, for example, by a preparation method as shown in the following Reaction Scheme 3:
wherein in Reaction Scheme 3, each X can be independently halogen, preferably bromo, or chloro, and the definitions of other substituents are the same as described above.
Specifically, the compound of Chemical Formula 3 is prepared by coupling the starting materials SM5 and SM6 through a Suzuki-coupling reaction. The Suzuki-coupling reaction is preferably carried out in the presence of a palladium catalyst and a base. Further, a reactive group for the Suzuki-coupling reaction can be appropriately modified, and the method for preparing the compound of Chemical Formula 3 can be further embodied in Preparation Examples described hereinafter.
Further, in one embodiment, at least one of the first compound, the second compound, and the third compound can contain deuterium in the compound. More specifically, the second compound can contain deuterium; or the third compound can contain deuterium; or the second compound and the third compound can simultaneously contain deuterium. In such a case, due to deuterium (D) contained in the compound in the light emitting layer, the vibration energy in a radical anion state can be lowered to have stable energy, whereby the formed exciplex can also be in a more stable state.
Meanwhile, a ratio of (the weight of the first compound) and (the total weight of the second compound and the third compound) in the light emitting layer can be 90:10 to 50:50, more specifically, 80:20 to 50:50. Preferably, a ratio of (the weight of the first compound) to the (the total weight of the second compound and the third compound) in the light emitting layer can be 60:40.
In other words, the first compound in the light emitting layer can be contained in an amount of 50 to 90% by weight based on the sum total weight of the first compound, the second compound, and the third compound. When the content of the first compound exceeds 90% by weight based on the sum total weight of the first compound, the second compound and the third compound, electron transport in the light emitting layer is not smooth, and so holes and electrons are out of balance as a whole device, which can cause problems with the voltage, efficiency and lifetime of the manufactured device. When the content is less than 50% by weight, conversely, hole transport in the light emitting layer is not smooth, which causes problems with the voltage, efficiency, and lifetime of the manufactured device.
Further, the third compound in the light emitting layer can be contained in an amount of 10% by weight or more, 15% by weight or more, 40% by weight or more, 30% by weight or more, or 25% by weight or less based on the sum total weight of the first compound, the second compound, and the third compound.
Further, the second compound and the third compound in the light emitting layer can be contained in a weight ratio of 1:9 to 9:1. The degree of electron transfer can be finely adjusted through adjustment of the weight ratio. For example, the weight ratio of the second compound to the third compound in the light emitting layer can be 2:8 to 8:2, 3:7 to 7:3, 4:6 to 6:4, or 5:5.
Meanwhile, the light emitting layer can further include a dopant material in addition to the three types of host materials. The dopant material can include an aromatic amine derivative, a styrylamine compound, a boron complex, a fluoranthene compound, a metal complex, and the like. Specifically, the aromatic amine derivative is a substituted or unsubstituted fused aromatic ring derivative having an arylamino group, and examples thereof include pyrene, anthracene, chrysene, periflanthene and the like, which have an arylamino group. The styrylamine compound is a compound where at least one arylvinyl group is substituted in substituted or unsubstituted arylamine, in which one or two or more substituent groups selected from the group consisting of an aryl group, a silyl group, an alkyl group, a cycloalkyl group, and an arylamino group are substituted or unsubstituted. Specific examples thereof include styrylamine, styryldiamine, styryltriamine, styryltetramine, and the like, but are not limited thereto. Further, the metal complex includes an iridium complex, a platinum complex, and the like, but is not limited thereto.
In this case, the dopant material can be contained in an amount of 1 to 25% by weight based on the sum total weight of the host material and the dopant material in the light emitting layer.
The organic light emitting device according to the present disclosure can include a hole blocking layer between the light emitting layer and an electron transport layer described hereinafter, if necessary. The hole blocking layer refers to a layer which is formed on the light emitting layer, preferably provided in contact with the light emitting layer, and serves to adjust the electron mobility, prevent excessive movement of holes, and increase the probability of hole-electron coupling, thereby improving the efficiency of the organic light emitting device. The hole blocking layer includes a hole blocking material, and examples of such hole blocking material can include a compound having an electron withdrawing group introduced therein, such as azine derivatives including triazine; triazole derivatives; oxadiazole derivatives; phenanthroline derivatives; phosphine oxide derivatives, but is not limited thereto.
The electron transport layer is formed between the light emitting layer and the cathode and serves to receive electrons from an electron injection layer and transports the electrons up to the light emitting layer. The electron transport layer includes an electron transport material, and the electron transport material is suitably a material which can receive electrons well from a cathode and transfer the electrons to a light emitting layer, and has a large mobility for electrons.
Specific examples of the electron injection and transport material include: an Al complex of 8-hydroxyquinoline; a complex including Alq3; an organic radical compound; a hydroxyflavone-metal complex, and the like, but are not limited thereto. Alternatively, these materials can be used together with fluorenone, anthraquinodimethane, diphenoquinone, thiopyran dioxide, oxazole, oxadiazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenylidene methane, anthrone, and the like, and derivatives thereof, a metal complex compound, a nitrogen-containing 5-membered ring derivative, and the like, but are not limited thereto.
The organic light emitting device according to the present disclosure can include an electron injection layer between the electron transport layer and the cathode, if necessary.
The electron injection layer is disposed between the electron transport layer and the cathode, and serves to inject electrons from an electrode. The electron injection layer includes an electron injection material, and the electron injection material is suitably a material which has a capability of transporting electrons, has an excellent effect of injecting electrons into a light emitting layer or a light emitting material, and is also excellent in the ability to form a thin film.
Specific examples of the electron injection material include LiF, NaCl, CsF, Li2O, BaO, fluorenone, anthraquinodimethane, diphenoquinone, thiopyran dioxide, oxazole, oxadiazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenylidene methane, anthrone, and the like, and derivatives thereof, a metal complex compound, a nitrogen-containing 5-membered ring derivative, and the like, but are not limited thereto.
Examples of the metal complex compound include 8-hydroxyquinolinato lithium, bis(8-hydroxyquinolinato)zinc, bis(8-hydroxyquinolinato)copper, bis(8-hydroxyquinolinato)manganese, tris(8-hydroxyquinolinato)aluminum, tris(2-methyl-8-hydroxyquinolinato)aluminum, tris(8-hydroxyquinolinato)gallium, bis(10-hydroxybenzo[h]quinolinato)-beryllium, bis(10-hydroxybenzo[h]quinolinato)zinc, bis(2-methyl-8-quinolinato)chlorogallium, bis(2-methyl-8-quinolinato)(o-cresolato)gallium, bis(2-methyl-8-quinolinato)(1-naphtholato)aluminum, bis(2-methyl-8-quinolinato)(2-naphtholato)gallium, and the like, but are not limited thereto.
The organic light emitting device according to the present disclosure is illustrated in
The organic light emitting device according to the present disclosure can be manufactured by sequentially stacking the above-described structures. In this case, the organic light emitting device can be manufactured by depositing a metal, metal oxides having conductivity, or an alloy thereof on the substrate by using a PVD (physical vapor deposition) method such as a sputtering method or an e-beam evaporation method to form the anode, forming the respective layers described above thereon, and then depositing a material that can be used as the cathode thereon. In addition to such a method, the organic light emitting device can be manufactured by sequentially depositing from the cathode material to the anode material on a substrate. Further, the light emitting layer can be formed by subjecting hosts and dopants to a vacuum deposition method and a solution coating method. Herein, the solution coating method means a spin coating, a dip coating, a doctor blading, an inkjet printing, a screen printing, a spray method, a roll coating, or the like, but is not limited thereto.
In addition to such a method, the organic light emitting device can be manufactured by sequentially depositing a cathode material, an organic material layer and an anode material on a substrate (International Publication WO2003/012890). However, the manufacturing method is not limited thereto.
Meanwhile, the organic light emitting device according to the present disclosure can be a bottom emission type device, a top emission type device, or a double side emission type device, and in particular, it can be a bottom emission type light emitting device that requires relatively high luminous efficiency.
The preparation of the organic light emitting device will be described in detail by way of the following examples. However, these examples are for illustrative purposes only, and are not intended to limit the scope of the present disclosure.
5,8-Dihydroindolo[2,3-c]carbazole (15 g, 58.5 mmol) and 4-bromo-1,1′-biphenyl(13.6 g, 58.5 mmol) were added to 300 ml of toluene under a nitrogen atmosphere, and the mixture was stirred and refluxed. Then, sodium tert-butoxide (16.9 g, 175.6 mmol) was added thereto and sufficiently stirred, and then bis(tri-tert-butylphosphine)palladium (0.9 g, 1.8 mmol) was added. After reacting for 2 hours, the reaction mixture was cooled to room temperature, and the organic layer was filtered to remove salts, and then the filtered organic layer was distilled. This was again added to and dissolved in 328 ml of chloroform, washed twice with water, and then the organic layer was separated, anhydrous magnesium sulfate was added thereto, stirred, and then filtered, and the filtrate was distilled under reduced pressure. The concentrated compound was purified through silica column using hexane and toluene and then subjected to sublimation purification to give a white solid compound 1-1 (17.4 g, 53%, MS: [M+H]+=561.7).
5,8-Dihydroindolo[2,3-c]carbazole (30 g, 117 mmol) and 4-bromo-1,1′-biphenyl (27.3 g, 117 mmol) were added to 600 ml of toluene under a nitrogen atmosphere, and the mixture was stirred and refluxed. Then, sodium tert-butoxide (33.8 g, 351.1 mmol) was added thereto and sufficiently stirred, and then bis(tri-tert-butylphosphine)palladium (1.8 g, 3.5 mmol) was added. After reacting for 3 hours, the reaction mixture was cooled to room temperature, and the organic layer was filtered to remove salts, and then the filtered organic layer was distilled. This was again added to and dissolved in 478 ml of chloroform, washed twice with water, and then the organic layer was separated, anhydrous magnesium sulfate was added thereto, stirred, and then filtered, and the filtrate was distilled under reduced pressure. The concentrated compound was purified through silica column using hexane and toluene to give a yellow solid compound 1-2-1 (34.9 g, 73%, MS: [M+H]+=409.5).
Compound 1-2-1 (15 g, 36.7 mmol) and 3-bromo-1,1′-biphenyl (8.6 g, 36.7 mmol) were added to 300 ml of toluene under a nitrogen atmosphere, and the mixture was stirred and refluxed. Then, sodium tert-butoxide (10.6 g, 110.2 mmol) was added thereto and sufficiently stirred, and then bis(tri-tert-butylphosphine)palladium (0.6 g, 1.1 mmol) was added. After reacting for 4 hours, the reaction mixture was cooled to room temperature, and the organic layer was filtered to remove salts, and then the filtered organic layer was distilled. This was again added to and dissolved in 206 ml of chloroform, washed twice with water, and then the organic layer was separated, anhydrous magnesium sulfate was added thereto, stirred, and then filtered, and the filtrate was distilled under reduced pressure. The concentrated compound was purified through silica column using hexane and toluene to give a white solid compound 1-2 (13.4 g, 65%, MS: [M+H]+=561.7).
Compound 1-3 (54%, MS: [M+H]+=637.8) was prepared by the same method as the preparation method of Compound 1-2, except that in step 2 of Synthesis Example 1-2, 3-bromo-1,1′-biphenyl was changed to 2-bromo-1,1′: 3′,1″-terphenyl.
Compound 1-4 (16.6 g, 71%, MS: [M+H]+=637.8) was prepared by the same method as the preparation method of Compound 1-2, except that in step 2 of Synthesis Example 1-2, 3-bromo-1,1′-biphenyl was changed to 5′-bromo-1,1′: 3′,1″-terphenyl.
Compound 1-5 (14.4 g, 70%, MS: [M+H]+=561.7) was prepared by the same method as the preparation method of Compound 1-1, except that in Synthesis Example 1-1, 4-bromo-1,1′-biphenyl was changed to 3-bromo-1,1′-biphenyl.
Compound 1-6 (11.9 g, 51%, MS: [M+H]+=637.8) was prepared by the same method as the preparation method of Compound 1-2, except that in step 1 of Synthesis Example 1-2, 4-bromo-1,1′-biphenyl was changed to 3-bromo-1,1′-biphenyl, and in step 2 of Synthesis Example 1-2, 3-bromo-1,1′-biphenyl was changed to 3-bromo-1,1′: 3′,1″-terphenyl.
Compound 1-7 (13.1 g, 55%, MS: [M+H]+=651.8) was prepared by the same method as the preparation method of Compound 1-2, except that in step 1 of Synthesis Example 1-2, 5,8-dihydroindolo[2,3-c]carbazole was changed to 5,7-dihydroindolo[2,3-b]carbazole, and 4-bromo-1,1′-biphenyl was changed to 2-bromodibenzo[b,d]furan, and in step 2 of Synthesis Example 1-2, 3-bromo-1,1′-biphenyl was changed to 4-bromo-1,1′: 3′,1″-terphenyl.
Compound 1-8 (13.8 g, 67%, MS: [M+H]+=561.7) was prepared by the same method as the preparation method of Compound 1-1, except that in Synthesis Example 1-1, 5,8-dihydroindolo[2,3-c]carbazole was changed to 5,11-dihydroindolo[3,2-b]carbazole, and 4-bromo-1,1′-biphenyl was changed to 3-bromo-1,1′-biphenyl.
Compound 1-9 (15.4 g, 66%, MS: [M+H]+=637.8) was prepared by the same method as the preparation method of Compound 1-2, except that in step 1 of Synthesis Example 1-2, 5,8-dihydroindolo[2,3-c]carbazole was changed to 5,12-dihydroindolo[3,2-a]carbazole and in step 2 of Synthesis Example 1-2, 3-bromo-1,1′-biphenyl was changed to 4-bromo-1,1′:3′,1″-terphenyl.
11,12-Dihydroindolo[2,3-a]carbazole-1,3,5,6,8,10-d6 (20 g, 76.2 mmol) and bromobenzene (12 g, 76.2 mmol) were added to 400 ml of toluene under a nitrogen atmosphere, and the mixture was stirred and refluxed. Then, sodium Cert-butoxide (22 g, 228.7 mmol) was added thereto and sufficiently stirred, and then bis(tri-tert-butylphosphine)palladium (1.2 g, 2.3 mmol) was added. After reacting for 4 hours, the reaction mixture was cooled to room temperature, and the organic layer was filtered to remove salts, and then the filtered organic layer was distilled. This was again added to and dissolved in 258 ml of chloroform, washed twice with water, and then the organic layer was separated, anhydrous magnesium sulfate was added thereto, stirred, and then filtered, and the filtrate was distilled under reduced pressure. The concentrated compound was purified through silica column using hexane and toluene to give a yellow solid compound 2-1-1 (13.2 g, 51%, MS: [M+H]+=339.4).
Compound 2-1-1 (15 g, 44.3 mmol) and 2-([1,1′-biphenyl]-4-yl)-4-chloro-6-phenyl-1,3,5-triazine (18.3 g, 53.2 mmol) were added to 300 mL of dimethylformamide under a nitrogen atmosphere, and the mixture was stirred and refluxed. Then, potassium carbonate (18.4 g, 133 mmol) was added, heated and stirred. After reacting for 2 hours, the reaction mixture was cooled to room temperature, and the organic layer was filtered to remove salts, and then the filtered organic layer was distilled. This was again added to and dissolved in 286 ml of chloroform, washed twice with water, and then the organic layer was separated, anhydrous magnesium sulfate was added thereto, stirred, and then filtered, and the filtrate was distilled under reduced pressure. The concentrated compound was purified through silica column using hexane and toluene and then subjected to sublimation purification to give a yellow solid compound 2-1 (15.2 g, 53%, MS: [M+H]+=646.8).
11-Phenyl-11,12-dihydroindolo[2,3-a]carbazole (15 g, 45.1 mmol) and 2-chloro-4-(dibenzo[b,d]furan-3-yl)-6-phenyl-1,3,5-triazine (19.4 g, 54.1 mmol) were added to 300 mL of dimethylformamide under a nitrogen atmosphere, and the mixture was stirred and refluxed. Then, potassium carbonate (18.7 g, 135.4 mmol) was added, heated and stirred. After reacting for 3 hours, the reaction mixture was cooled to room temperature, and the organic layer was filtered to remove salts, and then the filtered organic layer was distilled. This was again added to and dissolved in 295 ml of chloroform, washed twice with water, and then the organic layer was separated, anhydrous magnesium sulfate was added thereto, stirred, and then filtered, and the filtrate was distilled under reduced pressure. The concentrated compound was purified through silica column using hexane and toluene and then subjected to sublimation purification to give a yellow solid compound 2-2 (22.7 g, 77%, MS: [M+H]+=654.8).
Compound 2-3 (22.4 g, 74%, MS: [M+H]+=670.8) was prepared by the same method as the preparation method of Compound 2-2, except that in Synthesis Example 2-2, 2-chloro-4-(dibenzo[b,d]furan-3-yl)-6-phenyl-1,3,5-triazine was changed to 2-chloro-4-(dibenzo[b,d]thiophen-4-yl)-6-phenyl-1,3,5-triazine.
Compound 2-4 (14.2 g, 54%, MS: [M+H]+=716.9) was prepared by the same method as the preparation method of Compound 2-1, except that in step 1 of Synthesis Example 2-1, 11,12-dihydroindolo[2,3-a]carbazole-1,3,5,6,8,10-d6 was changed to 11,12-dihydroindolo[2,3-a]carbazole, and bromobenzene was changed to 3-bromo-1,1′-biphenyl, and in step 2,2-([1,1′-biphenyl]-4-yl)-4-chloro-6-phenyl-1,3,5-triazine was changed to 2-([1,1′-biphenyl]-3-yl)-4-chloro-6-phenyl-1,3,5-triazine.
Compound 2-5 (19 g, 71%, MS: [M+H]+=730.8) was prepared by the same method as the preparation method of Compound 2-1, except that in step 1 of Synthesis Example 2-1, 11,12-dihydroindolo[2,3-a]carbazole-1,3,5,6,8,10-d6 was changed to 11,12-dihydroindolo[2,3-a]carbazole, and bromobenzene was changed to 3-bromo-1,1′-biphenyl, and in step 2, 2-([1,1′-biphenyl]-4-yl)-4-chloro-6-phenyl-1,3,5-triazine was changed to 2-chloro-4-(dibenzo[b,d]furan-1-yl)-6-phenyl-1,3,5-triazine.
12-Phenyl-5,12-dihydroindolo[3,2-a]carbazole (15 g, 45.1 mmol) and 2-(3-bromophenyl)-4,6-diphenyl-1,3,5-triazine (17.5 g, 45.1 mmol) were added to 300 mL of toluene under a nitrogen atmosphere, and the mixture was stirred and refluxed. Then, sodium tert-butoxide (13 g, 135.4 mmol) was added thereto and sufficiently stirred, and then bis(tri-tert-butylphosphine)palladium (0.7 g, 1.4 mmol) was added. After reacting for 3 hours, the reaction mixture was cooled to room temperature, and the organic layer was filtered to remove salts, and then the filtered organic layer was distilled. This was again added to and dissolved in 289 ml of chloroform, washed twice with water, and then the organic layer was separated, anhydrous magnesium sulfate was added thereto, stirred, and then filtered, and the filtrate was distilled under reduced pressure. The concentrated compound was purified through silica column using hexane and toluene and then subjected to sublimation purification to give a yellow solid compound 2-6 (20.2 g, 70%, MS: [M+H]+=640.8).
Compound 2-7 (22.5 g, 78%, MS: [M+H]+=640.8) was prepared by the same method as the preparation method of Compound 2-2, except that in Synthesis Example 2-2, 11-phenyl-11,12-dihydroindolo[2,3-a]carbazole was changed to 5-phenyl-5,8-dihydroindolo[2,3-c]carbazole, and 2-chloro-4-(dibenzo[b,d]furan-3-yl)-6-phenyl-1,3,5-triazine was changed to 2-([1,1′-biphenyl]-4-yl)-4-chloro-6-phenyl-1,3,5-triazine.
Compound 2-8 (22.4 g, 60%, MS: [M+H]+=641.8) was prepared by the same method as the preparation method of Compound 2-6, except that in Synthesis Example 2-6, 12-phenyl-5,12-dihydroindolo[3,2-a]carbazole was changed to 12H-benzofuro[2,3-a]carbazole, and 2-(3-bromophenyl)-4,6-diphenyl-1,3,5-triazine was changed to 2-([1,1′-biphenyl]-4-yl)-4-(3-bromophenyl)-6-phenyl-1,3,5-triazine.
Compound 2-9 (23.1 g, 64%, MS: [M+H]+=657.8) was prepared by the same method as the preparation method of Compound 2-6, except that in Synthesis Example 2-6, 12-phenyl-5,12-dihydroindolo[3,2-a]carbazole was changed to 12H-benzo[4,5]thieno[3,2-a]carbazole, and 2-(3-bromophenyl)-4,6-diphenyl-1,3,5-triazine was changed to 2-([1,1′-biphenyl]-3-yl)-4-(3-bromophenyl)-6-phenyl-1,3,5-triazine.
(7-Chlorodibenzo[b,d]furan-1-yl)boronic acid (20 g, 81.2 mmol) and 2-([1,1′-biphenyl]-4-yl)-4-chloro-6-phenyl-1,3,5-triazine (27.9 g, 81.2 mmol) were added to 400 mL of tetrahydrofuran under a nitrogen atmosphere, and the mixture was stirred and refluxed. Then, potassium carbonate (33.6 g, 243.5 mmol) dissolved in 100 mL of water, was added thereto and sufficiently stirred, and then tetrakistriphenyl-phosphinopalladium (2.8 g, 2.4 mmol) was added. After reacting for 3 hours, the reaction mixture was cooled to room temperature, and the resulting solid was filtered. The solid was added to and dissolved in 828 mL of chloroform, washed twice with water, and then the organic layer was separated, anhydrous magnesium sulfate was added thereto, stirred, and then filtered, and the filtrate was distilled under reduced pressure. The concentrated compound was purified through silica column using hexane and toluene to give a white solid compound 3-1-1 (31.5 g, 76%, MS: [M+H]+=511).
Compound 3-1-1 (15 g, 29.4 mmol) and 9H-carbazole (4.9 g, 29.4 mmol) were added to 300 mL of toluene under a nitrogen atmosphere, and the mixture was stirred and refluxed. Then, sodium tert-butoxide (8.5 g, 88.2 mmol) was added thereto and sufficiently stirred, and then bis(tri-tert-butylphosphine)palladium (0.5 g, 0.9 mmol) was added. After reacting for 1 hour, the reaction mixture was cooled to room temperature, and the organic layer was filtered to remove salts, and then the filtered organic layer was distilled. This was again added to and dissolved in 188 ml of chloroform, washed twice with water, and then the organic layer was separated, anhydrous magnesium sulfate was added thereto, stirred, and then filtered, and the filtrate was distilled under reduced pressure. The concentrated compound was purified through silica column using hexane and toluene and then subjected to sublimation purification to give a yellow solid compound 3-1 (10.6 g, 56%, MS: [M+H]+=641.8).
Compound 3-2 (22.2 g, 64%, MS: [M+H]+=571.7) was prepared by the same method as the preparation method of Compound 3-1, except that in step 1 of Synthesis Example 3-1, (7-chlorodibenzo[b,d]furan-1-yl)boronic acid was changed to (8-chlorodibenzo[b,d]furan-3-yl)boronic acid, and 2-([1,1′-biphenyl]-4-yl)-4-chloro-6-phenyl-1,3,5-triazine was changed to 2-chloro-4,6-diphenyl-1,3,5-triazine, and in step 2, 9H-carbazole was changed to 9H-carbazole-1,3,4,5,6,8-d6.
Compound 3-3 (28 g, 71%, MS: [M+H]+=648.8) was prepared by the same method as the preparation method of Compound 3-1, except that in step 1 of Synthesis Example 3-1, (7-chlorodibenzo[b,d]furan-1-yl)boronic acid was changed to (6-chlorodibenzo[b,d]furan-1-yl)boronic acid, 2-([1,1′-biphenyl]-4-yl)-4-chloro-6-phenyl-1,3,5-triazine was changed to 2-([1,1′-biphenyl]-3-yl)-4-chloro-6-phenyl-1,3,5-triazine, and in step 2, 9H-carbazole was changed to 9H-carbazole-1,2,3,4,5,6,8-d7.
Compound 3-4 (26.2 g, 65%, MS: [M+H]+=663.8) was prepared by the same method as the preparation method of Compound 3-1, except that in step 1 of Synthesis Example 3-1, (7-chlorodibenzo[b,d]furan-1-yl)boronic acid was changed to (9-chlorodibenzo[b,d]furan-3-yl)boronic acid, 2-([1,1′-biphenyl]-4-yl)-4-chloro-6-phenyl-1,3,5-triazine was changed to 2-chloro-4-(dibenzo[b,d]-furan-1-yl)-6-phenyl-1,3,5-triazine, and in step 2, 9H-carbazole was changed to 9H-carbazole-1,2,3,4,5,6,7,8-d8.
Compound 3-5 (24.5 g, 60%, MS: [M+H]+=671.8) was prepared by the same method as the preparation method of Compound 3-1, except that in step 1 of Synthesis Example 3-1, (7-chlorodibenzo[b,d]furan-1-yl)boronic acid was changed to (9-chlorodibenzo[b,d]thiophen-4-yl)boronic acid, and 2-([1,1′-biphenyl]-4-yl)-4-chloro-6-phenyl-1,3,5-triazine was changed to 2-chloro-4-(dibenzo[b,d]furan-3-yl)-6-phenyl-1,3,5-triazine.
(9-Chlorodibenzo[b,d]furan-3-yl)boronic acid (20 g, 81.2 mmol) and 2-chloro-4,6-diphenyl-1,3,5-triazine (21.7 g, 81.2 mmol) were added to 400 mL of tetrahydrofuran under a nitrogen atmosphere, and the mixture was stirred and refluxed. Then, potassium carbonate (33.6 g, 243.5 mmol) was dissolved in 100 mL of water, added thereto and sufficiently stirred, and then tetrakistriphenyl-phosphinopalladium (2.8 g, 2.4 mmol) was added. After reacting for 2 hours, the reaction mixture was cooled to room temperature, and the resulting solid was filtered. The solid was added to and dissolved in 704 mL of chloroform, washed twice with water, and then the organic layer was separated, anhydrous magnesium sulfate was added thereto, stirred, and then filtered, and the filtrate was distilled under reduced pressure. The concentrated compound was purified through silica column using hexane and toluene to give a white solid compound 3-6-1 (20.4 g, 58%, MS: [M+H]+=434.9).
Compound 3-6-1 (15 g, 34.6 mmol) and (9-phenyl-9H-carbazol-3-yl-1,2,4,5,6,7,8-d7)boronic acid (10.2 g, 34.6 mmol) were added to 300 mL of Diox under a nitrogen atmosphere, and the mixture was stirred and refluxed. Then, tripotassium phosphate (22 g, 103.7 mmol) was dissolved in 66 mL of water, added thereto, and sufficiently stirred, and then dibenzylideneacetone palladium (0.6 g, 1 mmol) and tricyclohexylphosphine (0.6 g, 2.1 mmol) were added. After reacting for 6 hours, the reaction mixture was cooled to room temperature, and the resulting solid was filtered. The solid was added to and dissolved in 672 mL of chloroform, washed twice with water, and then the organic layer was separated, anhydrous magnesium sulfate was added thereto, stirred, and then filtered, and the filtrate was distilled under reduced pressure. The concentrated compound was purified through silica column using hexane and toluene and then subjected to sublimation purification to give a yellow solid compound 3-6 (11.4 g, 51%, MS: [M+H]+=648.8).
Compound 3-7 (22.9 g, 58%, MS: [M+H]+=648.8) was prepared by the same method as the preparation method of Compound 3-6, except that in step 1 of Synthesis Example 3-6, (9-chlorodibenzo[b,d]furan-3-yl)boronic acid was changed to (8-chlorodibenzo[b,d]furan-1-yl)boronic acid, and in step 2, (9-phenyl-9H-carbazol-3-yl-1,2,4,5,6,7,8-d7)boronic acid was changed to triphenylen-2-ylboronic acid.
Compound 3-8 (18.8 g, 58%, MS: [M+H]+=568.7) was prepared by the same method as the preparation method of Compound 3-6, except that in step 1 of Synthesis Example 3-6, (9-chlorodibenzo[b,d]furan-3-yl)boronic acid was changed to (9-chlorodibenzo[b,d]thiophen-2-yl)boronic acid, and in step 2, (9-phenyl-9H-carbazol-3-yl-1,2,4,5,6,7,8-d7)boronic acid was changed to [1,1′-biphenyl]-4-ylboronic acid.
A glass substrate on which ITO (indium tin oxide) was coated as a thin film to a thickness of 1400 Å was put into distilled water in which a detergent was dissolved, and ultrasonically cleaned. At this time, a product manufactured by Fischer Co. was used as the detergent, and as the distilled water, distilled water filtered twice using a filter manufactured by Millipore Co. was used. After the ITO was cleaned for 30 minutes, ultrasonic cleaning was repeated twice using distilled water for 10 minutes. After the cleaning with distilled water was completed, the substrate was ultrasonically cleaned with solvents of isopropyl alcohol, acetone and methanol, dried, and then transferred to a plasma cleaner. In addition, the substrate was cleaned for 5 minutes using oxygen plasma and then transferred to a vacuum depositor.
On the transparent ITO electrode thus prepared, 95 wt % of the following compound HT-A and 5 wt % of the following compound PD were thermally vacuum deposited to a thickness of 100 Å to form a hole injection layer, and then, only the compound HT-A was deposited to a thickness of 1150 Å to form a hole transport layer. The following compound HT-B was thermally vacuum deposited to a thickness of 450 Å thereon to form an electron blocking layer.
Then, 92 wt % of host in which the first host compound 1-1, the second host compound 2-2, and the third host compound 3-2 were mixed in a weight ratio of 60:20:20, and 8 wt % of the following compound GD were vacuum deposited to a thickness of 350 Å on the electronic blocking layer to form a light emitting layer.
Then, the following compound ET-A was vacuum deposited to a thickness of 50 Å as a hole blocking layer. Then, the following compounds ET-B and Liq were thermally vacuum deposited in a ratio of 1:1 to a thickness of 300 Å as an electron transport layer, and then Yb was vacuum deposited to a thickness of 10 Å as an electron injection layer.
Magnesium and silver were deposited in a ratio of 1:4 to a thickness of 150 Å on the electron injection layer to form a cathode, thereby manufacturing an organic light emitting device.
In the above-mentioned process, the vapor deposition rate of the organic material was maintained at 0.4 to 0.7 Å/sec, the deposition rate of magnesium and silver was maintained at 2 Å/sec, and the degree of vacuum during the deposition was maintained at 2*10−7 to 5*10−6 torr.
The organic light emitting devices of Examples 2 to 30 and Comparative Examples 1 to 9 were respectively manufactured in the same manner as in Example 1, except that the host materials were changed as shown in Tables 1 to 3 below. In this case, the ratio means a weight ratio of the first host, the second host, and the third host. In addition, each of the GH-A, GH-B, and GH-C compounds listed in Table 1 is as follows.
The organic light emitting devices prepared in Examples 1 to 30 and Comparative Examples 1 to 9 were heat-treated in an oven at 120° C. for 30 minutes, then taken out, and the voltage, efficiency and lifetime (T95) were measured by applying a current, and the results are shown in Tables 1 to 3 below. At this time, the voltage and efficiency were measured by applying a current density of 10 mA/cm2, and T95 means the time (hr) required for the luminance to be reduced to 95% of the initial luminance at a current density of 20 mA/cm2.
From Tables 1 to 3 above, it is confirmed that the organic light emitting devices of Examples 1 to 30 are remarkably low in the driving voltage and are significantly improved in the efficiency and lifetime, as compared to the organic light emitting devices of Comparative Examples 1 to 9.
The first compound has aryl, dibenzofuranyl, or dibenzothiophenyl substituents as a substituent in the indolocarbazole-based mother nucleus structure, has excellent hole transport capability and serves as a P-type host, and the second compound and the third compound having pyridine, pyrimidine, or triazine substituents serve as N-type hosts.
When the P-type host and an N-type host are mixed and applied as a host of the light emitting layer, an exciplex is formed, so that the characteristics of the device can be improved, as compared with when only any one of the P-type host and the N-type host is applied. This can be confirmed from the facts that the organic light emitting devices of Examples 1 to 30 in which a P-type host and an N-type host are mixed and applied as a host of the light emitting layer exhibits significantly lower driving voltage and significantly improved efficiency and lifetime characteristics, as compared with the organic light emitting devices of Comparative Examples 1 to 4 in which only any one of the P-type host and the N-type host is applied.
Furthermore, it is confirmed that the organic light emitting devices of Examples in which the P-type host of the first compound is mixed with two N-type hosts of the second compound and the third compound (first compound+second compound+third compound) are improved in characteristics of the device, as compared with the organic light emitting devices of Comparative Examples 5 and 6 in which only one N-type host is mixed with a P-type host of the first compound (first compound+second compound; or first compound+third compound).
Thereby, it can be seen that the P-type host of the first compound exhibits low voltage characteristics due to its structure containing indolocarbazole, the N-type host of the second compound exists as a monomolecular exciton, thereby contributing to energy transfer to the dopant and electrical stability in the light emitting layer, and exhibiting long lifetime characteristics, and the N-type host of the third compound has a structure containing dibenzofuran/dibenzothiophene and assists in electron injection and transfer to exhibit high-efficiency characteristics, so that the mixed use of these contributes to even improvement of the voltage, efficiency and lifetime characteristics of the device.
Further, it can be seen that the organic light emitting devices of Examples are generally improved in the voltage, efficiency and lifetime characteristics, as compared with the organic light emitting device of Comparative Example 8 in which a compound having a structure different from that of the third compound is used as an N-type host. This means that when the third compound is mixed with the first compound and the second compound, it exhibits a synergistic effect of voltage, efficiency and lifetime characteristics due to differences in electrical stability, electron transfer capability, and the like.
In addition, it can be seen that the organic light emitting devices of Examples are generally improved in the voltage, efficiency and lifetime characteristics, as compared with the organic light emitting devices of Comparative Examples 7 to 9 in which a compound having a structure different from those of the first compound, the second compound, and the third compound is used as a host. This means that when the first compound, the second compound and the third compound are mixed and used, it exhibits synergistic effects in voltage, efficiency and lifetime characteristics due to differences in electrical stability (GH-A, GH-B), electron transfer capability (GH-B), and energy transfer capability (GH-C).
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2020-0096124 | Jul 2020 | KR | national |
| 10-2021-0099976 | Jul 2021 | KR | national |
This application is a National Stage Application of International Application No. PCT/KR2021/009995 filed on Jul. 30, 2021, which claims priority to and the benefit of Korean Patent Application No. 10-2020-0096124 filed on Jul. 31, 2020 and Korean Patent Application No. 10-2021-0099976 filed on Jul. 29, 2021 in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2021/009995 | 7/30/2021 | WO |
