KR102493459B1 - N-heterocyclic compound and organic light emitting device comprising the same - Google Patents

Abstract

The present invention relates to a novel N-heterocyclic compound and an organic light emitting device including the same, and when the N-heterocyclic compound according to the present invention is used as a material for an organic material layer, emission characteristics such as luminous efficiency, power efficiency, and quantum efficiency An organic light emitting device with improved power consumption can be realized by inducing an increase in the light emitting characteristic.

Description

N-heterocyclic compound and an organic light emitting device containing the same {N-HETEROCYCLIC COMPOUND AND ORGANIC LIGHT EMITTING DEVICE COMPRISING THE SAME}

The present invention relates to a novel N-heterocyclic compound and an organic light emitting device including the same.

An organic light emitting device emits light while electrons and holes form pairs when charge is injected into an organic film formed between an electron injection electrode (cathode) and a hole injection electrode (anode) and then disappears. This can not only form a device on a flexible transparent substrate such as plastic, but also can be driven at a lower voltage than a plasma display panel or an inorganic EL (Electro Luminescence) display. In addition, it has advantages of relatively low power consumption, wide viewing angle, excellent contrast, and fast response speed.

A typical organic light emitting device includes a substrate, an anode, a hole injection layer that accepts holes from the anode, a hole transport layer that transports holes, a light emitting layer that emits light by combining holes and electrons, and an electron transport layer that accepts electrons from the cathode and transfers them to the light emitting layer. and a cathode. In some cases, the light emitting layer may be formed by doping the electron transport layer or the hole transport layer with a small amount of fluorescent or phosphorescent dye without a separate light emitting layer. may be performed simultaneously.

As mentioned above, the organic light emitting device has a structure in which an organic material layer is disposed between an anode and a cathode. As voltage is applied to the organic light emitting device, electrons and holes injected from the electrodes combine in the organic material layer to form a pair and emit light while disappearing. For example, as a material of the organic material layer, a compound capable of constituting the light emitting layer alone may be used, or a mixture of compounds capable of serving as a host or dopant of the light emitting layer may be used. In addition, as a material for the organic layer, a compound capable of performing functions such as hole injection, hole transport, electron blocking, hole blocking, electron transport, and electron injection may be used.

Accordingly, development of organic material layer materials to improve the performance, lifespan or efficiency of the organic light emitting device is still continuously required. In particular, there is an urgent need to develop a compound that can serve as a host for the light emitting layer and a compound that can be used for the electron transport layer.

KR 10-2016-0017055 A KR 10-2019-0075322 A KR 10-1994837 B1

An object of the present invention is to provide an organic light emitting compound that is a novel N-heterocyclic compound.

In addition, an object of the present invention is to provide an organic light emitting device with improved power consumption by lowering a driving voltage and inducing an increase in power efficiency and quantum efficiency by using the N-heterocyclic compound as a material for an organic material layer.

For the above purpose, the present invention provides an N-heterocyclic compound represented by Formula 1 below.

[Formula 1]

[In Chemical Formula 1,

Ar is a substituted or unsubstituted 6-membered heteroaryl backbone;

R ¹ is hydrogen, deuterium, halogen, cyano, C1-C30 alkyl, C3-C30 cycloalkyl, C6-C30 aryl, C3-C30 heteroaryl, or combinations thereof;

R ² is halogen, cyano, C1-C30 alkyl, C3-C30 cycloalkyl, C6-C30 aryl, C3-C30 heteroaryl or combinations thereof;

n is an integer selected from 0 to 3, and when n is an integer of 2 or 3, R ² may be the same as or different from each other, and when n is 0, all three substituents are hydrogen;

m is an integer of 2 or 3;

The substitution of Ar is C1-C30 alkyl, halogen, cyano, C3-C30 cycloalkyl, C1-C30 alkoxy, C6-C30 aryloxy, C6-C30 aryl, mono or diC1-C30 alkylamino, mono or diC6 -C30 on any carbon atom by one or more substituents selected from the group consisting of arylamino, nitro, hydroxy, etc., and combinations thereof; The heteroaryl each independently includes one or more selected from B, N, O, S, P(=O), Si, and P; The substituents repeated by n or m may be the same as or different from each other.]

In addition, the present invention provides an organic light emitting device including the N-heterocyclic compound represented by Chemical Formula 1 above.

The N-heterocyclic compound according to the present invention is chemically stable and has high electron density by introducing two or more benzothiazole groups into a 6-membered heteroaryl skeleton derived from pyridine, pyrimidine, pyrazine, pyridazine, triazine, etc. have In addition, the glass transition temperature (Tg) is also excellent in thermal stability. The present invention has an advantage in that such high thermal stability is an important factor in providing driving stability to an organic light emitting device.

The N-heterocyclic compound according to the present invention can exert an effective effect as a material for an organic layer of an organic light emitting device. Specifically, the N-heterocyclic compound according to the present invention can be used as an organic material layer material capable of exhibiting effective effects in an organic light emitting device, such as a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer. In particular, according to the present invention, it is used as a material for a light emitting layer, exhibiting excellent light emitting characteristics and suppressing leakage of current. In addition, it is used as a material for the electron transport layer to help ensure that electrons are quickly injected into the light emitting layer and electrons and holes injected from the electrodes are injected into the light emitting layer in a balanced manner.

Therefore, the organic light emitting device employing the N-heterocyclic compound according to the present invention can lower the driving voltage of the device and induces an increase in light emitting characteristics such as power efficiency and quantum efficiency, thereby improving power consumption. has the advantage of providing In addition, it has an advantage of being able to provide an organic light emitting device having long lifespan characteristics.

1 is a diagram schematically showing a stacked structure of an organic light emitting device (Device 1) according to an embodiment of the present invention;
2 is a graph showing current density (mA/cm 2 ) and luminance (cd/m 2 ) of an organic light emitting device (Device 1) at 0 to 15 V according to an embodiment of the present invention;
3 is a graph showing current efficiency (cd/A) versus luminance (cd/m2) of an organic light emitting device (Device 1) according to an embodiment of the present invention;
4 is a graph showing power efficiency (Im/W) versus luminance (cd/m2) of an organic light emitting device (Device 1) according to an embodiment of the present invention;
5 is a diagram schematically showing a stacked structure of an organic light emitting device (Device 2) according to an embodiment of the present invention;
6 is a graph showing current density (mA/cm 2 ) and luminance (cd/m 2 ) of an organic light emitting device (Device 2) at 0 to 15 V according to an embodiment of the present invention;
7 is a graph showing current efficiency (cd/A) versus luminance (cd/m2) of an organic light emitting device (Device 2) according to an embodiment of the present invention;
8 is a graph showing power efficiency (Im/W) versus luminance (cd/m2) of an organic light emitting device (Device 2) according to an embodiment of the present invention;
9 is a diagram schematically showing a stacked structure of an organic light emitting device (Device 3) according to an embodiment of the present invention;
10 is a graph showing current density (mA/cm 2 ) and luminance (cd/m 2 ) at 0 to 15 V of an organic light emitting device (Device 3) according to an embodiment of the present invention;
11 is a graph showing current efficiency (cd/A) versus luminance (cd/m2) of an organic light emitting device (Device 3) according to an embodiment of the present invention;
12 is a graph showing power efficiency (Im/W) versus luminance (cd/m 2 ) of an organic light emitting device (Device 3) according to an embodiment of the present invention.

The N-heterocyclic compound according to the present invention and the organic light emitting device including the same are detailed below, but unless otherwise defined in the technical terms and scientific terms used at this time, those skilled in the art to which this invention belongs It has a commonly understood meaning, and descriptions of known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted in the following description.

As used herein, the term “alkyl” and other substituents including “alkyl” moieties are organic radicals derived from aliphatic hydrocarbons by the removal of one hydrogen, and include both straight-chain and branched forms. In addition, as for substituents containing alkyl, alkoxy and other alkyl moieties according to the present invention, short-chain substituents having 1 to 7 carbon atoms are preferred, but long-chain substituents having 8 or more carbon atoms are also an aspect of the present invention.

In addition, as used herein, the term “aryl” is an organic radical derived from an aromatic hydrocarbon by removing one hydrogen, and is a single ring containing 4 to 7, preferably 5 or 6, ring atoms in each ring. Or it includes a fused ring system, and even includes a form in which a plurality of aryls are connected by single bonds. Examples include phenyl, naphthyl, biphenyl, terphenyl, anthryl, indenyl, fluorenyl, phenanthryl, triphenylenyl, pyrenyl, perylenenyl, chrysenyl, naphthacenyl, fluoranthenyl, and the like. , but not limited thereto.

In addition, the term "heteroaryl" used herein is an organic radical derived from an aromatic ring skeleton, and includes 1 to 4 atoms selected from B, N, O, S. Si and P as ring members (ring atoms) of the skeleton. An aryl group containing a heteroatom and the remaining aromatic ring skeletal members being carbon. In addition, in the present specification, a 6-membered heteroaryl skeleton is an aromatic ring skeleton containing the aforementioned heteroatom, and means an aromatic ring skeleton including at least one N atom. For example, the 6-membered heteroaryl skeleton may be derived from pyridine, pyrimidine, pyrazine, pyridazine, triazine, and the like.

In addition, the term "cycloalkyl" used herein is an organic radical derived from a fully saturated or partially unsaturated alicyclic hydrocarbon ring, and includes fused cyclic, bridged cyclic and spirocyclic groups. For example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, decalin, bicycle[3.1.1]heptane, bicyclo[2.2.1]heptane, bicyclo[2.2.2]octane, bicycle[3.2. 2]nonane, spiro[2.5]octane, spiro[3.5]nonane, adamantyl, and the like.

In addition, as used herein, the term “alkoxy” means alkyl-O-*, and “aryloxy” means aryl-O-*. At this time, the alkyl and aryl follow the above definition.

In addition, the term “amino” used herein means *-NH ₂ .

Also, the term “halogen” used herein refers to a fluorine (F), chlorine (Cl), bromine (Br) or iodine (I) atom.

In addition, in this specification, the number of carbon atoms according to the definition of a substituent described in Formula 1 does not include the number of carbon atoms of a substituent that may be further substituted.

The N-heterocyclic compound according to the present invention has a 6-membered heteroaryl skeleton containing at least one nitrogen atom as a parent nucleus, and has two or three benzothiazole groups, which may or may not be substituted, on any carbon atom of the parent nucleus. It is a compound with a novel structure opened.

In addition, the N-heterocyclic compound is an organic material that has use in an organic light emitting device and exhibits an effective effect by being included in organic material layers such as a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer.

Specifically, the N-heterocyclic compound is chemically stable and has a high electron density. In addition, it has thermal stability, that is, a high glass transition temperature (Tg), which may be an important factor in providing driving stability to an organic light emitting device. In addition, the N-heterocyclic compound according to the present invention improves interfacial properties between organic materials and has improved solubility in various organic solvents. Accordingly, the N-heterocyclic compound according to the present invention has an advantage that it can be applied in various aspects as an organic material for an organic light emitting device.

Hereinafter, the present invention will be described in detail.

In the present invention, an N-heterocyclic compound represented by Formula 1 is provided.

[Formula 1]

[In Chemical Formula 1,

Ar is a substituted or unsubstituted 6-membered heteroaryl backbone;

R ¹ is hydrogen, deuterium, halogen, cyano, C1-C30 alkyl, C3-C30 cycloalkyl, C6-C30 aryl, C3-C30 heteroaryl, or combinations thereof;

R ² is halogen, cyano, C1-C30 alkyl, C3-C30 cycloalkyl, C6-C30 aryl, C3-C30 heteroaryl or combinations thereof;

n is an integer selected from 0 to 3, and when n is an integer of 2 or 3, R ² may be the same as or different from each other, and when n is 0, all three substituents are hydrogen;

m is an integer of 2 or 3;

The substitution of Ar is C1-C30 alkyl, halogen, cyano, C3-C30 cycloalkyl, C1-C30 alkoxy, C6-C30 aryloxy, C6-C30 aryl, mono or diC1-C30 alkylamino, mono or diC6 -C30 on any carbon atom by one or more substituents selected from the group consisting of arylamino, nitro, hydroxy, etc., and combinations thereof; The heteroaryl each independently includes one or more selected from B, N, O, S, P(=O), Si, and P; The substituents repeated by n or m may be the same as or different from each other.]

Due to the structural characteristics described above, the N-heterocyclic compound can realize high luminous efficiency, and thus can be used as a material for the light emitting layer.

In addition, this can remove energy barriers related to electron injection and provide an electron transport layer having an appropriate HOMO energy level and LUMO energy level, which can be used as a material for the electron transport layer. In addition, leakage of holes and leakage of current are effectively suppressed, and electrons are rapidly injected into the light emitting layer so that electrons can be injected into the light emitting layer in a balanced manner.

N-heterocyclic compound according to an embodiment of the present invention, in terms of implementing excellent luminous efficiency and improved drive lifespan, Ar is pyridine, pyrimidine, pyrazine, pyridazine or 6-membered derived from triazine, etc. It may have a heteroaryl backbone.

In one aspect, when the N-heterocyclic compound has two benzothiazole groups, Ar may be selected from Structural Formula 1 below.

[Structural Formula 1]

[In the above structure,

R ¹¹ and R ¹² are independently of each other C1-C30 alkyl, halogen, cyano, C3-C30 cycloalkyl, C1-C30 alkoxy, C6-C30 aryloxy, C6-C30 aryl or combinations thereof;

R ¹³ is hydrogen, C1-C30 alkyl, halogen, cyano, C3-C30 cycloalkyl, C1-C30 alkoxy, C6-C30 aryloxy, C6-C30 aryl or combinations thereof;

a is an integer selected from 0 to 3, and when a is 0, all three substituents are hydrogen;

b is an integer selected from 0 to 2, and when b is 0, both substituents are hydrogen.]

As described above, when m in Formula 1 is 2, that is, when an N-heterocyclic compound having two benzothiazole groups is used as the electron transport layer material, the difference between the HOMO energy level of the electron transport layer and the HOMO energy level of the light emitting material layer raise Thus, hole leakage is effectively blocked.

Specifically, in Formula 1, when m is 2, Ar is selected from Formula 1; wherein R ¹ is hydrogen, halogen, cyano, C1-C30 alkyl, C6-C30 aryl, C3-C30 heteroaryl, or combinations thereof; R ² is C1-C30 alkyl, C3-C30 cycloalkyl or a combination thereof; The n may be an integer selected from 0 to 3.

Specifically, in Formula 1, when m is 2, Ar is selected from Formula 1; wherein R ¹ is hydrogen, halogen, cyano, C1-C7 alkyl, C6-C12 aryl, C3-C12 heteroaryl, or combinations thereof; wherein R ² is C1-C7 alkyl, C3-C12 cycloalkyl or a combination thereof; The n may be an integer selected from 0 to 3.

Specifically, in Formula 1, when m is 2, Ar is selected from Formula 1; R ¹ is halogen, cyano, C1-C7 alkyl, fluoride C1-C7 alkyl, aryl such as phenyl, naphthyl or biphenyl, or heteroaryl such as pyridine, pyrimidine, pyrazine, pyridazine, triazine, and the like. ; wherein R ² is C1-C7 alkyl; The n may be an integer of 0 or 1.

Specifically, in Chemical Formula 1, n may be an integer of 0.

Specifically, Ar is selected from Structural Formula 1, and R ¹¹ , R ¹² and R ¹³ may each independently be hydrogen, halogen, cyano, C1-C7 alkyl or fluorinated C1-C7 alkyl.

Specifically, Ar is selected from Structural Formula 1, and R ¹¹ , R ¹² and R ¹³ may independently represent hydrogen or halogen.

In another aspect, when the N-heterocyclic compound has three benzothiazole groups, Ar may be selected from Structural Formula 2 below.

[Structural Formula 2]

[In the above structure,

R ¹⁴ is C1-C30 alkyl, halogen, cyano, C3-C30 cycloalkyl, C1-C30 alkoxy, C6-C30 aryloxy, C6-C30 aryl or combinations thereof;

R ¹⁵ is hydrogen, C1-C30 alkyl, halogen, cyano, C3-C30 cycloalkyl, C1-C30 alkoxy, C6-C30 aryloxy, C6-C30 aryl or combinations thereof;

b is an integer selected from 0 to 2, and when b is 0, both substituents are hydrogen.]

As described above, when m in Formula 1 is 3, that is, when an N-heterocyclic compound having 3 benzothiazole groups is used as the electron transport layer material, the difference between the HOMO energy level of the electron transport layer and the HOMO energy level of the light emitting material layer raise more In addition, when this is used as a material for the light emitting layer, a significantly improved light emitting characteristic is realized and a low driving voltage is enabled.

Specifically, when m is 3 in Formula 1, Ar is selected from Formula 2; wherein R ¹ is hydrogen, halogen, cyano, C1-C30 alkyl, C6-C30 aryl, C3-C30 heteroaryl, or combinations thereof; R ² is C1-C30 alkyl, C3-C30 cycloalkyl or a combination thereof; The n may be an integer selected from 0 to 3.

Specifically, when m is 3 in Formula 1, Ar is selected from Formula 2; wherein R ¹ is hydrogen, halogen, cyano, C1-C7 alkyl, C6-C12 aryl, C3-C12 heteroaryl, or combinations thereof; wherein R ² is C1-C7 alkyl, C3-C12 cycloalkyl or a combination thereof; The n may be an integer selected from 0 to 3.

Specifically, when m is 3 in Formula 1, Ar is selected from Formula 2; R ¹ is halogen, cyano, C1-C7 alkyl, fluoride C1-C7 alkyl, aryl such as phenyl, naphthyl or biphenyl, or heteroaryl such as pyridine, pyrimidine, pyrazine, pyridazine, triazine, and the like. ; wherein R ² is C1-C7 alkyl; The n may be an integer of 0 or 1.

Specifically, in Chemical Formula 1, n may be an integer of 0.

Specifically, Ar is selected from Structural Formula 2, and R ¹⁴ and R ¹⁵ may each independently be hydrogen, halogen, cyano, C1-C7 alkyl or fluorinated C1-C7 alkyl.

Specifically, Ar is selected from Structural Formula 2, and R ¹⁴ and R ¹⁵ may independently represent hydrogen or halogen.

The N-heterocyclic compound according to one embodiment of the present invention has excellent chemical and thermal stability. In addition, in order to satisfy improved luminous efficiency, power efficiency, quantum efficiency, etc., the substitution position of the benzothiazole group substituted in the mother nucleus may be variously modified.

Specifically, the substitution position of the benzothiazole group to be substituted in the parent nucleus may be 4 times, 5 times, 6 times or 7 times. Its specific substitution position can be understood from Structural Formula 3 below.

[Structural Formula 3]

For example, when the substitution position of the benzothiazole group substituted in the mother nucleus is 5, it is possible to provide an organic light emitting device having a lower driving voltage and driving stability, thereby providing an organic light emitting device with improved power consumption. good in terms

For example, when the benzothiazole group substituted in the mother nucleus is 4th, 6th or 7th, it also satisfies a low driving voltage and implements improved light emission characteristics. These results suggest that the substitution position of the benzothiazole group can be appropriately modified according to the purpose without limitation.

Accordingly, more specifically, the N-heterocyclic compound according to an embodiment of the present invention may be at least one selected from compounds represented by Formulas 2 to 5 below.

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

[In Formula 2 to Formula 5,

A ₁ and A ₂ are each independently -N= or -CH=;

R ¹ are each independently halogen, cyano, C1-C30 alkyl, C6-C30 aryl, C3-C30 heteroaryl, or a combination thereof, and each R ₁ may be identical to or different from each other;

R ² are independently of each other C1-C30 alkyl, C3-C30 cycloalkyl or a combination thereof;

n is an integer independently selected from 0 to 3.]

Specifically, in Formulas 2 to 5, R ¹ is each independently halogen, cyano, C1-C7 alkyl, C6-C12 aryl, C3-C12 heteroaryl, or a combination thereof; wherein R ² is each independently C1-C7alkyl, C3-C12cycloalkyl, or a combination thereof; The n may be an integer selected from 0 to 3.

Specifically, in Formulas 2 to 5, R ¹ is each independently selected from halogen, cyano, C1-C7 alkyl, haloC1-C7 alkyl, aryl such as phenyl, naphthyl or biphenyl, pyridine, or pyrimidine. , Heteroaryls such as pyrazine, pyridazine, and triazine; R ² are each independently C1-C7 alkyl; The n may be an integer of 0 or 1.

Specifically, in Chemical Formulas 2 to 5, n may be an integer of 0.

Most specifically, the N-heterocyclic compound according to an embodiment of the present invention may be at least one selected from compounds represented by Structural Formula 3 and Structural Formula 4 below, but is not limited thereto.

[Structural Formula 3]

[Structural Formula 4]

An N-heterocyclic compound according to an embodiment of the present invention may be prepared as shown in Reaction Scheme 1 below, but is not limited thereto, and may be prepared through a known organic reaction.

[Scheme 1]

[In Scheme 1 above,

The definition of each substituent is the same as that in Formula 3 above;

R is C1-C3 alkyl;

Hal is halogen.]

In addition, the present invention provides an organic light emitting device including the N-heterocyclic compound. Specifically, the organic light emitting device according to the present invention may include the N-heterocyclic compound in one or more organic material layers interposed between the first electrode and the second electrode.

In one aspect, the organic light emitting device according to the present invention may include the N-heterocyclic compound in the light emitting layer.

In another aspect, the light emitting layer may include the N-heterocyclic compound as a host material. In addition, it goes without saying that the light emitting layer may be used in the form of a mixture by further including a commercially available host material.

In another aspect, the organic light emitting device according to the present invention may include the N-heterocyclic compound in an electron transport layer.

In another aspect, the electron transport layer may be used in the form of a stack of two or more layers including different organic materials. In this case, at least one electron transport layer may include the N-heterocyclic compound. That is, the first electron transport layer containing the N-heterocyclic compound and one side of the first electron transport layer are located adjacent to the light emitting layer, and the other side is located adjacent to the second electron transport layer, but the second electron transport layer is It may include a compound different from the N-heterocyclic compound included in the first electron transport layer or a commercial electron transport layer organic material.

In another aspect, the organic light emitting device according to the present invention may include the N-heterocyclic compound in an organic layer such as a hole injection layer, a hole transport layer, or an electron injection layer.

In another aspect, the organic light emitting device according to the present invention comprises the N-heterocyclic compound having a different structure in at least two or more layers selected from organic material layers such as a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer. may include

Hereinafter, the organic light emitting device of the present invention will be described in detail.

An organic light emitting device according to an embodiment of the present invention includes a first electrode; a second electrode; and one or more organic material layers interposed between the first electrode and the second electrode, and the organic material layer may have a single-layer structure or a multi-layer structure of two or more layers including a light emitting layer. When the organic material layer of the organic light emitting device has a multi-layer structure, it may have, for example, a structure in which at least one layer selected from a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer is stacked. However, the structure of the organic light emitting device is not limited thereto.

The first electrode may be an anode and is an electrode for injecting holes into the hole injection layer. Therefore, as long as the material for forming the anode is imparted with properties to the anode, it is not limited. Examples of materials for forming the anode include metals such as vanadium, chromium, copper, zinc, and gold, or alloys thereof; or a conductive polymer; etc. can be mentioned. Specifically, 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, poly(3-methylthiophene) , poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDT), polypyrrole, and conductive polymers such as polyaniline, but are not limited thereto. In addition, the anode layer may be formed of only one type of the above materials or may be formed of a mixture of a plurality of materials, and a multilayer structure composed of a plurality of layers of the same composition or different compositions may be formed.

The organic material layer may include a hole injection layer (HIL), a hole blocking layer (HBL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), an electron injection layer (EIL), and the like. may be omitted. The organic layer may be formed by a vacuum deposition method or a solution coating method. Examples of the solution application method include, but are not limited to, spin coating, dip coating, doctor blading, inkjet printing, or thermal transfer.

The organic material layer includes the N-heterocyclic compound according to the present invention.

Specifically, the N-heterocyclic compound may be included in the light emitting layer. In this case, the light emitting layer may include a commercial light emitting layer material, and may be used by further mixing the N-heterocyclic compound of Formula 1. Thus, the organic light emitting device according to the present invention implements more improved light emitting characteristics. In this case, the light-emitting layer material may include at least one selected from silane-based compounds and phosphine oxide-based compounds as a host material. In addition, the light emitting layer may further include a dopant. At this time, as the dopant material, common red, green, and blue dopants may be used. The red dopant used in the light emitting layer may be Bt ₂ Ir(acac), Ir(piq) ₃ , etc., and the green dopant may be Ir(ppy) ₃ , Ir(ppy) ₂ (acac), Ir(mpyp) ₃ , etc. may be used, and Firpic, DPAVBi, etc. may be used as the blue dopant, but is not limited thereto.

The light emitting layer may be a light emitting layer exhibiting phosphorescence. As mentioned above, by including the N-heterocyclic compound of Chemical Formula 1 according to the present invention, an organic light emitting device having high luminance and long lifespan characteristics can be implemented. In the light emitting layer of the organic light emitting device of the present invention, the film thickness of the light emitting layer is not limited, but from the viewpoint of preventing the uniformity of the film or the application of unnecessary high voltage during light emission, and improving the stability of the light emission color with respect to the driving current, 2 nm to 5 μm, 5 to 50 nm, or 10 to 40 nm.

In addition, the light emitting layer can obtain a high luminance color with higher efficiency by using a phosphorescent dopant together. In this case, the dopant used is not limited, and a known dopant may be selected and used according to need. The phosphorescent dopant is a compound that can emit light from triplet excitons, and is not particularly limited as long as it emits light from triplet excitons. A specific example may be a metal complex including one or more metals selected from the group consisting of Ir, Ru, Pd, Pt, Os, and Re, and may be a porphyrin metal complex or an ortho metallized metal complex.

For example, the porphyrin metal complex may be specifically a porphyrin platinum complex.

For example, the ortho metallized metal complex is a 2-phenylpyridine (ppy) derivative, a 7,8-benzoquinoline derivative, a 2-(2-thienyl)pyridine (2-(2-thienyl)pyridine, tp) derivative, 2-(1-naphthyl)pyridine (npy) derivative, 2-phenylquinoline (2-phenylquinoline, pq) derivative, etc. may be included as a ligand. These derivatives may have substituents as needed. As an auxiliary ligand, it may further have ligands other than the above ligands, such as acetylacetonato (acac) and picric acid. For example, bisthienylpyridine acetylacetonate iridium, bis (2-benzo [b] thiophen-2-yl-pyridine) (acetylacetonato) iridium (III) (bis (2-benzo [b]thiophen-2-yl-pyridine)(acetylacetonato)iridium(III), Ir(btp) ₂ (acac)), bis(2-phenylbenzothiazole)(acetylacetonato)iridium(III) (bis (2-phenylbenzothiazole)(acetylacetonato)iridium(III), Ir(bt) ₂ (acac)), bis(1-phenylisoquinoline)(acetylacetonato)iridium(III) (bis(1-phenylisoquinoline)(acetylacetonato )Iridium(III), Ir(piq) ₂ (acac)), tris(1-phenylisoquinoline)iridium(III) (tris(1-phenylisoquinoline)iridium(III), Ir(piq) ₃ ), tris(2 -phenylpyridine) iridium (III) (tris (2-phenylpyridine) iridium (III), Ir (ppy) ₃ ), tris (2-biphenylpyridine) iridium (tris (2-biphenylpyridine) iridium), tris (3- Biphenylpyridine) iridium (tris (3-biphenylpyridine) iridium), tris (4-biphenylpyridine) iridium (tris (4-biphenylpyridine) iridium), and the like, but are not limited thereto.

The amount of the dopant included in the light emitting layer is not limited, but for example, it may be included in the range of 2 to 20 parts by weight based on 100 parts by weight of the host material (Formula 1), and the total dopant content is 0.5 to 35 parts by weight with respect to the total weight of the light emitting layer. It can be within the % range.

Specifically, the N-heterocyclic compound may be included in the electron transport layer.

The electron transport layer (ETL) is mainly composed of a material containing a chemical component that attracts electrons. To this end, high electron mobility is required and electrons are stably supplied to the light emitting layer through smooth electron transport. Accordingly, as the electron transport layer adopts the N-heterocyclic compound, it is possible to realize a low driving voltage and provide improved driving stability. Also, current leakage is effectively suppressed. For the electron transport layer, the N-heterocyclic compound may be used as a single material or may be used in combination with a conventional electron transport layer material to give synergistic effects to desired effects. Typical electron transport layer materials include, for example, TSPO1 (diphenyl[4-(triphenylsilyl)phenyl]phosphine oxide), TPBi (1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene); Alq ₃ (tris(8-hydroxyquinolinato)aluminum); BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline); PBD (2-(4-biphenyl)-5-(4-tert-butyl-phenyl)-1,3,4-oxadizole), TAZ (3-(4-biphenyl)-4-phenyl-5-(4- tert-butyl-phenyl)-1,2,4-triazole), OXD-7 (1,3-bis[2-(4-tert-butylphenyl)-1,3,4-oxadiazo-5-yl]benzene) azole compounds such as; tris(phenylquinoxaline) (TPQ); TmPyPB (3,3'-[5'-[3-(3-Pyridinyl)phenyl][1,1':3',1''-terphenyl]-3,3''-diyl]bispyridine) etc. may, but is not limited thereto. Preferably, TSPO1, TPBi or Alq3 may be used, and in one embodiment of the present invention, compound 1 (N2-246NS) or the N-heterocyclic compound according to the present invention is used together with TSPO1 or TPBi to form an electron transport layer, It was confirmed that a more improved luminous efficiency could be implemented. At this time, the electron transport layer may be laminated on top of the light emitting layer to a thickness of 5 to 150 nm, the first electron transport layer containing the N-heterocyclic compound according to the present invention and the second electron transport layer containing TSPO1 or TPBi It may be layered. At this time, the thickness ratio (a:b) of the first electron transport layer (a) and the second electron transport layer (b) is not limited, but may be 1:10 to 1:0.1, specifically 1:10 to 1: can be 1 In addition, the thickness means a direction perpendicular to the long axis of the electron transport layer. In addition, the stacked electron transport layers may be stacked such that the first electron transport layer is adjacent to the light emitting layer and the second electron transport layer is adjacent to the light emitting layer.

The hole injection layer (HIL) may be formed on the first electrode using various methods such as a vacuum deposition method, a spin coating method, a cast method, a Langmuir-Blodgett (LB) method, and the like. The material is, for example, CuPc (copper phthalocyanine), NPD (N,N'-dinaphthyl-N,N'-phenyl-(1,1'-biphenyl)-4,4'-diamine), m-MTDATA (4, 4',4"-tris(3-Methylphenylphenylamino)triphenylamine), 1-TNATA (4,4',4''-tris[1-naphthyl(phenyl)amino]triphenylamine), 2-TNATA (4,4', Aromatic amines such as 4''-tris[2-naphthyl(phenyl)amino]triphenylamine), p-DPA-TDAB (1,3,5-tris[N-(4-diphenylaminophenyl)phenylamino]benzene), as a conductive polymer A polythiophene derivative, poly(3,4-ethylenedioxythiophene)-poly(styrnesulfonate) (PEDOT:PSS), etc. In the embodiment of the present invention, PEDOT:PSS was used as the hole injection layer, and the hole injection layer It may be coated on top of the first electrode to a thickness of 10 to 60 nm.

In addition, the hole transport layer (HTL) is formed using various methods such as vacuum deposition, spin coating, cast method, LB method, etc. It can be. As the material of the hole transport layer that can be used, commonly used materials may be used, for example, NPB (N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-benzidine) , NPD (N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-2,2'-dimethylbenzidine), mCP (1,3-Bis(N-carbazolyl)benzene), TPD (N,N'-Bis(3-methylphenyl)-N,N'-diphenylbenzidine), TTB (N,N,N',N'-tetrakis(4-methylphenyl)-(1,1'-biphenyl)- 4,4-diamine), TTP (N1,N4-diphenyl-N1,N4-dim-tolylbenzene-1,4-diamine), ETPD (N,N'-bis(4-methylphenyl)-N,N'-bis (4-ethylphenyl)-[1,1'-(3,3'-dimethyl)biphenyl]-4,4'-diamine), VNPB (N4,N4''-bis(4-vinylphenyl)biphenyl-4,4 ''-diamine), ONPB (N4,N4'-bis(4-(6-((3-ethyloxetan-3-yl)methoxy)hexyl)phenyl)-N4,N4'-diphenylbiphenyl-4,4'-diamine ), OTPD (N4,N4'-bis(4-(6-((3-ethyloxetan-3-yl)methoxy)hexyl)phenyl)-N4,N4'-diphenylbiphenyl-4,4'-diamine) hole transport materials; Polymer hole transport materials such as poly-N-vinylcarbazole (PVK), polyaniline, and (phenylmenyl) polysilane may be used. For example, NPD, mCP or PVK may be used. In addition, the hole transport layer may be stacked on top of the light emitting layer to a thickness of 10 to 60 nm.

In addition, a hole blocking layer (HBL) may be formed to prevent diffusion of triplet excitons or holes into the electron transport layer. In the case of forming the hole blocking layer by the vacuum deposition method or the spin coating method, the conditions vary depending on the compound used, but generally can be within the same range of conditions as those for forming the hole injection layer. A known hole-blocking material can also be used, and examples thereof include oxadiazole derivatives, triazole derivatives, and phenanthroline derivatives. As a more specific example, BCP or the like may be used as the hole blocking layer material.

In addition, the electron injection layer (EIL) may be deposited to a thickness of 1 to 50 nm using LIF or lithium quinolate (Liq), but is not limited thereto.

In addition, the second electrode may be a negative electrode, and specific examples include metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or alloys thereof, LiF A metal having a low work function, such as a multi-layered material such as /Al or LiO ₂ /Al, may be used, and more specifically, Al is preferable.

The organic light emitting diode according to the present invention exhibits an efficient energy transfer mechanism between the host and the dopant, and thus can exhibit reliable high-efficiency light emitting characteristics based on an effect of improving electron density distribution. In addition, it is possible to secure high-performance light-emitting characteristics having high efficiency and long lifespan in each color by overcoming the initial efficiency reduction characteristics and low lifespan characteristics of existing materials.

The organic light emitting device according to the present invention described above may be applied to a display device, and the display device may be a display device using a backlight unit, and the organic light emitting device may be used as a light source of a backlight unit and a single light source, The display device may be an organic light emitting display (OLED) or the like, but is not limited thereto.

Hereinafter, for a detailed understanding of the present invention, the N-heterocyclic compound according to the present invention, the preparation method thereof, and the light emitting characteristics of the device will be described with reference to representative compounds of the present invention, and the following examples illustrate the purpose of the present invention intended to limit the scope of protection of the present invention.

[Production Example 1]

Preparation of compound a-1 (5-BOONS)

5-bromo-2-methylbenzo[d]thiazole (5-bromo-2-methylbenzo[d]thiazole, 20 g, 87.7 mmol), 4,4,4',4',5,5,5',5'-octamethyl-2,2'-bi(1,3,2-dioxaborolan)(4,4,4',4',5,5,5',5'-octamethyl-2,2'-bi(1,3,2-dioxaborolane), 44.40 g, 174.8 mmol), potassium acetate (KOAc, 26 g) and Pd(dppf)Cl ₂ (2 g) were prepared in nitrogen atmosphere N , N'- It was dissolved in dimethylformamide (DMF, 400 mL). The reaction was stirred at 80 °C for 24 hours. Thereafter, after cooling to room temperature (25 ℃), an organic layer was obtained by extraction with ethyl acetate and water. The remaining moisture was removed using sodium sulfate (Na ₂ SO ₄ ), the solvent was removed under reduced pressure, and then purified through column chromatography to obtain compound a-1 as a white solid (22.9 g, yield: 95%). At this time, the developing solvent was used by mixing 1/9 of ethyl acetate/hexane.

¹ H NMR (400 MHz, CDCl ₃ , δ): 8.36 (s, 1H), 7.78 (d, 1H), 7.72 (d, 1H), 2.80 (s, 3H), 1.34 (s, 12H).

of comparative compound A (135NS) Produce

1,3,5-tribromobenzene (1,3,5-tribromobenzene, 5.49 g, 17.44 mmol), 5-BOONS (12 g, 43.6 mmol), Pd(PPh ₃ ) ₄ (1 g), nitrogen It was dissolved in tetrahydrofuran (THF, 30mL) and 2M potassium carbonate (K ₂ CO ₃ , 10mL) in the atmosphere. The reaction was stirred at 65 °C for 24 hours. Thereafter, after cooling to room temperature, an organic layer was obtained by extraction with ethyl acetate and water. The remaining moisture was removed using Na ₂ SO ₄ , the solvent was removed under reduced pressure, and then purified through column chromatography to obtain Compound A as a white solid (4.58 g, yield: 58%). At this time, the developing solvent was used by mixing ethyl acetate/hexane in a ratio of 3/7.

¹ H NMR (400 MHz, CDCl ₃ , δ): 8.30 (s, 3H), 7.95-7.91 (m, 6H), 7.74-7.70 (m, 3H), 2.88 (s, 9H).

[Production Example 2]

Preparation of compound a-2 (6-BOONS)

6-bromo-2-methylbenzo[d]thiazole (6-bromo-2-methylbenzo[d]thiazole, 1 g, 4.4mmol), 4,4,4',4',5,5,5',5'-octamethyl-2,2'-bi(1,3,2-dioxaborolan)(4,4,4',4',5,5,5',5'-octamethyl-2 ,2′-bi(1,3,2-dioxaborolane), 2.22 g, 8.7 mmol), potassium acetate (KOAc, 1.30 g) and Pd(dppf)Cl ₂ (0.10 g) were mixed with 1,4-dioxane in a nitrogen atmosphere. It was dissolved in cein (1,4-Dioxane, 20 mL). The reaction was stirred at 120 °C for 24 hours. Thereafter, after cooling to room temperature (25 ℃), an organic layer was obtained by extraction with ethyl acetate and water. The remaining moisture was removed using sodium sulfate (Na ₂ SO ₄ ), the solvent was removed under reduced pressure, and then purified through column chromatography to obtain compound a-2 as a white solid (0.94 g, yield: 78%). At this time, the developing solvent was used by mixing 1/9 of ethyl acetate/hexane.

¹ H NMR (400 MHz, CDCl ₃ , δ): 8.30 (s, 1H), 7.92 (d, 1H), 7.85 (d, 1H), 2.84 (s, 3H), 1.36 (s, 12H).

[Example 1]

Compound 1 (N2-246NS) Produce

2,4,6-trichloropyrimidine (2,4,6-trichloropyrimidine, 0.50 g, 2.7 mmol), 5-BOONS (3.34 g, 12.1 mmol), triphenylphosphine (PPh ₃ , 0.48 g) and Pd (OAc) ₂ (0.21g) was dissolved in 1,2-dimethoxyethane (25mL) and 2M Na ₂ CO ₃ (13mL) under a nitrogen atmosphere. Stirred at 90 °C for 24 hours. Thereafter, after cooling to room temperature, an organic layer was obtained by extraction with ethyl acetate and water. The remaining moisture was removed using Na ₂ SO ₄ , the solvent was removed under reduced pressure, and the resultant was purified through column chromatography to obtain Compound 1 as a white solid (0.83 g, yield: 58%). At this time, the developing solvent was used by mixing ethyl acetate/hexane in a ratio of 3/7.

¹ H NMR (400 MHz, CDCl ₃ , δ): 9.39 (s, 1H), 8.91 (s, 2H), 8.83-8.81 (m, 1H), 8.41-8.38 (m, 2H), 8.21 (s, 1H) ), 8.02–7.97 (m, 3 H), 2.91 (d, 9 H).

[Example 2]

compound 2 -1(Cl-N2- 46NS6 ) manufacture of

2,4,6-Trichloropyrimidine (0.50 g, 2.7 mmol), 6-BOONS (3.34 g, 12.1 mmol), PPh ₃ (0.48 g) and Pd(OAc) ₂ (0.21 g) were mixed with 1 Dissolve in 2-dimethoxyethane (25mL) and 2M Na ₂ CO ₃ (13mL). Stirred at 90 °C for 24 hours. Thereafter, after cooling to room temperature, an organic layer was obtained by extraction with ethyl acetate and water. The remaining moisture was removed using Na ₂ SO ₄ , and the solvent was removed under reduced pressure and purified through column chromatography to obtain compound 2-1 and compound 2-2 as white solids (0.3 g, yield: 27%). ). At this time, the developing solvent is used by mixing ethyl acetate/hexane in a ratio of 3:7.

Compound 2-1:

¹ H NMR (400 MHz, CDCl ₃ , δ): 8.05-7.99 (m, 4 H), 7.70 (m, 2H), 2.86 (s, 6H).

[Examples 3 to 7]

Compounds 3 to 7 were prepared in a similar manner to the preparation method of Example 1 or Example 2, and the data are shown in Table 1 below.

(Table 1)

[Example 8 and Example 9] Fabrication of organic light emitting device (Device 1, ETL-1)

An organic light emitting device employing the N-heterocyclic compound according to the present invention for an electron transport layer was manufactured (see FIG. 1). Specifically, the manufacturing method of the organic light emitting device is as follows.

As a substrate, ITO (indium tin oxide, 10 Ω per square) coated glass (25 mm × 25 mm × 0.7 mm size) was used and treated with UV ozone for 10 minutes before device fabrication after cleaning. Thereafter, the hole injection layer (HIL) was spin-coated with a PEDOT:PSS solution (Clevios AI 4083) at 3,200 rpm for 40 seconds to a thickness of 30 nm, and then dried in vacuum at 150 °C for 30 minutes. The light emitting layer (EML) on the hole injection layer is a solution of polyvinylcarbazole (PVK):Ir(mppy) ₃ = 93:7 (weight ratio) dissolved in 1,2-dichloroethane at 0.64% by weight at 1,800 rpm at 40 °C. It was spin-coated to a thickness of 30 nm for a second and the remaining solvent was removed at 60 °C for 30 minutes. Thereafter, Compound 1 (N2-246NS) synthesized according to Example 1 was vacuum thermally deposited at 0.5 Å/s to form a first electron transport layer (ETL-1) of 10 nm on the light emitting layer. TPBi(2,2',2"-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H) as a second electron transport layer (ETL-2) on the first electron transport layer -benzimidazole)) was vacuum thermal evaporated at 0.5 Å/s to form 40 nm LiF at 0.1 Å/s to a thickness of 1 nm and aluminum (Al) at 5.0 Å/s on the second electron transport layer. It was formed by vacuum thermal evaporation to a thickness of 100 nm with s. Coating and drying of the light emitting layer were performed in an inert atmosphere in a glove box filled with nitrogen. After fabrication of the final device, in the glove box, through epoxy adhesive and a glass cover. Sealed, Example 8 was produced.

In addition, Example 9 was manufactured by manufacturing an organic light emitting device in the same manner, but changing the thickness of the electron transport layer (ETL-1:ETL-2 = 10:40) to 15:35.

A light emission test was performed by applying a voltage of 0 to 15V to the organic light emitting device manufactured as described above, and the light emission characteristics and basic physical property measurement results are shown in Tables 2 to 4 and FIGS. 2 to 4 below.

[Comparative Example 1]

An organic light emitting device was fabricated in the same manner as in Example 8, but had only the first electron transport layer without the second electron transport layer. That is, the electron transport layer of Comparative Example 1 was formed to a thickness of 50 nm by vacuum thermal evaporation of TPBi at 0.5 Å/s.

A light emission test was performed by applying a voltage of 0 to 15V to the organic light emitting device manufactured as described above, and the light emission characteristics and basic physical property measurement results are shown in Tables 2 to 4 and FIGS. 2 to 4 below.

[Comparative Example 2 and Comparative Example 3]

An organic light emitting device was manufactured in the same manner as in Example 8 or Example 9, but the compound (135NS) synthesized according to Preparation Example 1 was used as the material of the first electron transport layer. That is, the electron transport layer of Comparative Example 2 was formed by vacuum thermal evaporation of the compound (135NS) synthesized according to Preparation Example 1 as a first electron transport layer at 0.5 Å/s to form a 10 nm thickness, and as a second electron transport layer (ETL-2) TPBi (ETL-1) was vacuum thermally deposited at 0.5 Å/s to form 40 nm.

In addition, Comparative Example 3 was prepared by fabricating an organic light emitting device in the same manner, but changing the thickness of the electron transport layer (ETL-1:ETL-2 = 10:40) to 15:35.

A light emission test was performed by applying a voltage of 0 to 15V to the organic light emitting device manufactured as described above, and the light emission characteristics and basic physical property measurement results are shown in Tables 2 to 4 and FIGS. 2 to 4 below.

(Table 2)

(Table 3)

(Table 4)

As shown in Tables 2 to 4 and FIGS. 2 to 4, it was confirmed that the organic light emitting device including the N-heterocyclic compound according to the present invention as an electron transport layer material realized significantly improved efficiency. Specifically, according to the present invention, it was confirmed that it was stably driven even at a low driving voltage compared to the comparative example and exhibited excellent light emitting characteristics in quantum efficiency. In addition, it was confirmed that such an effect was more remarkable as the luminance increased, and it could provide an advantage to the decrease in current efficiency and power efficiency according to the increase in luminance.

[Example 10 and Example 11] Fabrication of organic light emitting device (Device 2, ETL-2)

An organic light emitting device employing the N-heterocyclic compound according to the present invention for an electron transport layer was fabricated (see FIG. 5). Specifically, the manufacturing method of the organic light emitting device is as follows.

An organic light emitting device was fabricated in the same manner as in Example 8, but 40 nm was formed by vacuum thermal evaporation of TPBi at 0.5 Å / s as the first electron transport layer, and the second electron transport layer (ETL-2) as in Example 1 N2-246NS synthesized according to Example 10 was prepared by vacuum thermal evaporation at 0.5 Å/s to form 10 nm.

In addition, Example 11 was manufactured by manufacturing an organic light emitting device in the same manner, but changing the thickness of the electron transport layer (ETL-1:ETL-2 = 10:40) to 15:35.

A light emission test was performed by applying a voltage of 0 to 15V to the organic light emitting device manufactured as described above, and the light emission characteristics and basic physical property measurement results are shown in Tables 5 to 7 and FIGS. 6 to 8 below.

[Comparative Example 4]

An organic light emitting device was fabricated in the same manner as in Example 10, but had only the first electron transport layer without the second electron transport layer. That is, the electron transport layer of Comparative Example 4 was formed to a thickness of 50 nm by vacuum thermal evaporation of TPBi at 0.5 Å/s.

A light emission test was performed by applying a voltage of 0 to 15V to the organic light emitting device manufactured as described above, and the light emission characteristics and basic physical property measurement results are shown in Tables 5 to 7 and FIGS. 6 to 8 below.

(Table 5)

(Table 6)

(Table 7)

As shown in Tables 5 to 7 and FIGS. 6 to 8, it was confirmed that the organic light emitting device including the N-heterocyclic compound according to the present invention as an electron transport layer material implements improved efficiency even if the stacking type is different. . Specifically, according to the present invention, it was confirmed that it was stably driven even at a low driving voltage compared to the comparative example and exhibited excellent light emitting characteristics in quantum efficiency.

In addition, in the case of the electron transport layer (Device 2, ETL-2) stacked adjacent to the cathode, which is the second electrode, improved quantum efficiency is realized with a lower driving voltage, as well as higher current efficiency and power even when the luminance is increased. It was confirmed that efficiency could be realized. As a result, it was confirmed that more stable current efficiency and power efficiency can be implemented even at thousands of nits or tens of thousands of nits.

[Example 12 and Example 13] Fabrication of organic light emitting device (Device 3, EML)

An organic light emitting device using the N-heterocyclic compound according to the present invention in the light emitting layer was fabricated (see FIG. 9). Specifically, the manufacturing method of the organic light emitting device is as follows.

As a substrate, ITO (indium tin oxide, 10 Ω per square) coated glass (25 mm × 25 mm × 0.7 mm size) was used and treated with UV ozone for 10 minutes before device fabrication after cleaning. Thereafter, the hole injection layer (HIL) was spin-coated with a PEDOT:PSS solution (Clevios AI 4083) at 3,200 rpm for 40 seconds to a thickness of 30 nm, and then dried in vacuum at 150 °C for 30 minutes. The light emitting layer (EML) on the hole injection layer was spin coated with a solution of 0.64% by weight of host:dopant (Ir(mppy) ₃ )=93:7 in tetrahydrofuran at 1,800 rpm for 40 seconds to a thickness of 40 nm, The remaining solvent was removed at 60 °C for 30 minutes. The host was used by mixing TCTA (Tris(4-carbazoyl-9-ylphenyl)amine 97% | Sigma-Aldrich) and Compound 1 (N2-246NS) synthesized according to Example 1 at a molar ratio of 1:1. Thereafter, TPBi (2,2',2"-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole), ETL) was vacuumed at 0.5 Å/s as an electron transport layer on the light emitting layer. On the electron transport layer, LiF was deposited at 0.1 Å/s to a thickness of 1 nm and aluminum (Al) at 5.0 Å/s to a thickness of 100 nm on the electron transport layer. Coating and drying of the light emitting layer were performed in an inert atmosphere in a glove box filled with nitrogen After fabrication of the final device, it was sealed with an epoxy adhesive and a glass cover in the glove box to manufacture Example 12.

In addition, an organic light emitting device was manufactured in the same manner, but the light emitting layer material (TCTA: N2-246NS) of Example 12 was mixed with TAPC (4,4'-cyclohexylidenebis [N, N-bis (4-methylphenyl) benzenamine]) Example 13 was prepared by changing the compound 1 (N2-246NS) synthesized in Example 1 to a light-emitting layer material (TAPC: N2-246NS) mixed at a molar ratio of 1:1.

A light emission test was performed by applying a voltage of 0 to 15V to the organic light emitting device manufactured as described above, and the light emission characteristics and basic physical property measurement results are shown in Tables 8 to 10 and FIGS. 10 to 12 below.

[Comparative Examples 5 to 7]

An organic light emitting device was fabricated in the same manner as in Example 12, but only polyvinylcarbazole was used as a host material in the light emitting layer of Example 12 (Comparative Example 5), or the host material of the light emitting layer of Example 12 Changed to TPBi (2,2',2"-(1,3,5-Benzinetriyl)-tris (1-phenyl-1-H-benzimidazole) instead of Compound 1 (N2-246NS) synthesized according to Example 1 Thus, Comparative Example 6 was prepared.

In addition, an organic light emitting device was manufactured in the same manner as in Example 13, but TPBi was changed instead of Compound 1 (N2-246NS) synthesized according to Example 1, which is a host material among the light emitting layers of Example 13, Comparative Example 7 was produced.

A light emission test was performed by applying a voltage of 0 to 15V to the organic light emitting device manufactured as described above, and the light emission characteristics and basic physical property measurement results are shown in Tables 8 to 10 and FIGS. 10 to 12 below.

(Table 8)

(Table 9)

(Table 10)

As shown in Tables 8 to 10 and FIGS. 10 to 12, the organic light emitting device including the N-heterocyclic compound according to the present invention as a light emitting layer material balances the density of holes and electrons to maximize exciton formation As a result, it was confirmed that the driving voltage can be further lowered, and the efficiency, power efficiency, and quantum efficiency can be dramatically increased by effectively confining excitons in the light emitting layer. In addition, by suppressing the roll-off phenomenon at a high current density, it is possible to implement more excellent durability and thus have a long lifespan characteristic.

In addition, it was confirmed that remarkable power efficiency and current efficiency can be implemented at thousands or tens of thousands of nits, which is the luminance of an organic light emitting device that is actually used. Specifically, in the case of Example 12, which is an organic light emitting device including the N-heterocyclic compound according to the present invention as a light emitting layer material, the current efficiency improved by 290% or more compared to Comparative Example 5 using only polyvinylcarbazole as a host material. (At 10000 nit), and it was confirmed that the current efficiency improved by more than 190% compared to Comparative Example 6 in which TPBi was changed to TPBi instead of Compound 1 (N2-246NS) synthesized according to Example 1 as a host material (At 10000 nits). Such an effect is a synergistic effect that has not been recognized in the prior art, and there is no specific application example for this.

As described above, the embodiments of the present invention have been described in detail, but those of ordinary skill in the art to which the present invention pertains, without departing from the spirit and scope of the present invention defined in the appended claims. It will be possible to implement the invention by modifying it in various ways. Therefore, changes in future embodiments of the present invention will not deviate from the technology of the present invention.

Claims (12)

delete delete delete delete delete At least one N-heterocyclic compound selected from compounds represented by the following formulas 2 to 5:
[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

In Formula 2 to Formula 5,
A ₁ and A ₂ are each independently -N= or -CH=;
R ¹ is C1-C7 alkyl;
R ² are independently of each other C1-C7 alkyl;
n is 0. delete delete a first electrode; a second electrode; and one or more organic material layers interposed between the first electrode and the second electrode, wherein at least one layer of the organic material layers includes the N-heterocyclic compound according to claim 6, the organic light emitting device. According to claim 9,
The organic material layer,
An organic light emitting device comprising a light emitting layer, wherein the light emitting layer contains the N-heterocyclic compound. According to claim 10,
The organic material layer,
An organic light emitting device comprising an electron transport layer, wherein the electron transport layer contains the N-heterocyclic compound. According to claim 11,
The electron transport layer,
It includes a first electron transport layer and a second electron transport layer made of an organic material,
Wherein the first electron transport layer or the second electron transport layer includes the N-heterocyclic compound, the organic light emitting device.

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