KR20190064009A - Organic compounds having improved light emitting property, organic light emitting diode and orgnic light emitting device having the compounds - Google Patents

Abstract

The present invention relates to an organic compound having one or more carbazole moieties, and one or more dibenzofuran or dibenzothiophene moieties, and designed to have a difference between a singlet energy level and a triplet energy level greater than 0.3 eV. The organic compound of the present invention has excellent thermal stability and broad energy band gap between a singlet energy level and a triplet energy level. When light emission is implemented, exciton quenching due to interaction between triplet/singlet excitons and holes (or electrons)-polarons caused in the organic compound of the present invention is prevented, thereby efficiently delivering light emitting energy and not degrading a light emitting material due to non-light emitting dissipation. By applying the organic compound of the present invention, it is possible to manufacture an organic light emitting diode and an organic light emitting device having improved luminous efficiency and device lifetime.

Description

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

The present invention relates to an organic compound, and more particularly, to an organic compound having a light emitting property suitable for use in an organic light emitting layer of a light emitting diode, an organic light emitting diode including the same, and an organic light emitting device.

BACKGROUND ART [0002] Organic light emitting diodes (OLEDs) as one of widely used flat display devices are now attracting attention as display devices that quickly replace liquid crystal display devices. Organic light emitting diodes (OLEDs) are formed of thin organic thin films within 2000 Å, and it is possible to realize images in a single direction or in both directions depending on the configuration of the electrodes used. In addition, the organic light emitting diode display device can form a device on a flexible transparent substrate such as a plastic, so that it is easy to realize a flexible or foldable display device. In addition, the organic light emitting diode display device can be driven at a low voltage, has excellent color purity, and has a great advantage over a liquid crystal display device.

The organic light emitting diode includes a hole injection electrode (anode), an electron injection electrode (cathode), and an organic light emitting layer formed between the anode and the cathode. (EIL), an electron transport layer (ETL), an electron transport layer (ETL), and an electron injection layer (EIL) are sequentially stacked on the hole injection electrode. ). At this time, holes injected from the anode and electrons injected from the cathode are combined in the light emitting material layer to form an exciton (exciton) to become an unstable excited state, and a stable ground state ground state and emits light.

The practical efficiency characteristic of the organic light emitting diode is determined by the external quantum efficiency which finally measures the amount of light emitted to the outside. External quantum efficiency can be measured by factors such as internal quantum efficiency (IQE), charge balancing factor, emission quantum efficiency, and out-coupling efficiency.

When a hole and an electron meet to form an exciton, a singlet exciton in a paired spin form and a triplet exciton in an unpaired spin form are formed at a ratio of 1: 3 < / RTI > Since a general fluorescent material can not emit a triplet exciton because only a single exciton participates in light emission and the remaining 75% of triplet excitons can not participate in light emission, the internal quantum efficiency is only 0.25 . Therefore, when the factors such as the charge balance factor, the spin quantum efficiency, and the light extraction efficiency are all combined, the maximum luminous efficiency of the organic light emitting diode using the fluorescent material is only 5 to 7.5%.

A phosphorescent material has been developed to overcome the limitations of fluorescent materials, and heavy metal complexes are generally used as phosphorescent materials. In the case of the phosphorescent material, the singlet-state exciton transitions to the triplet state mostly through intersystem crossing (ISC), and the energy of the triplet state is transferred to the bottom by the strong spin- orbit coupling by heavy metal Lt; / RTI > As such, the phosphorescent material has a luminescent mechanism that converts both singlet energy and triplet energy into light. Therefore, the phosphorescent material can realize an external quantum efficiency of up to 20 to 30%.

However, the metal complex used as a conventional phosphorescent material has a very short life span and thus has limitations in commercialization. Particularly, since the blue phosphorescent material has a low color purity, it has a limitation in applying the blue phosphorescent material to a high-quality display. Furthermore, in order to prevent the triplet energy of the phosphorescent dopant from transferring back energy to the host, the triplet energy of the phosphorescent host must be higher than the triplet energy of the phosphorescent dopant. However, the organic materials that can be used as a phosphorescent host are extremely limited, because the organic aromatics are greatly reduced in triplet energy as conjugation is increased or the rings are fused rings. In addition, conventional phosphorescent hosts are designed to have an excessively high bandgap of 3.5 to 4.5 eV or higher in order to have high triplet energy. When a host having an excessively wide band gap is used, charge injection and transportation are not smooth, and therefore a high driving voltage is required, which may adversely affect lifetime characteristics of the device. Therefore, there is a need to develop a light emitting diode and a light emitting device using a light emitting material having excellent luminescence efficiency and improved lifetime characteristics.

It is an object of the present invention to provide an organic compound having an appropriate band gap and capable of preventing non-emission disappearance in a light emission process.

It is another object of the present invention to provide an organic light emitting diode and an organic light emitting device having good light emitting efficiency and improved lifetime characteristics.

According to one aspect of the present invention there is provided a process for the preparation of a compound of formula I in accordance with the invention which comprises reacting a first heteroaromatic moiety having at least one carbazole moiety with a first heteroaromatic moiety through a direct or suitable aromatic linkage, The branch provides an organic compound comprising a second heteroaromatic moiety.

For example, the organic compound may be represented by the following formula (1).

Formula 1

Wherein R ₁ to R ₂₃ are each independently selected from the group consisting of hydrogen, deuterium, tritium, silyl groups, C ₁ to C ₂₀ alkyl groups, C ₁ to C ₂₀ alkoxy groups, C ₁ to C ₂₀ alkylamine groups, C ₅ ~ C ₃₀ Homo aryl group, C ₄ ~ C ₃₀ heteroaryl group, C ₅ ~ C ₃₀ Homo alkylaryl group, C ₄ ~ C ₃₀ heteroaryl-alkyl aryl group, C ₅ ~ C ₃₀ Homo aryloxy group, C ₄ ~ C ₃₀ heteroaryloxy group, C ₅ ~ C ₃₀ Homo arylamine group, a C ₄ ~ C ₃₀ heteroaryl amine group, or adjacent groups unsubstituted or combined substituted each other C ₅ ~ C _30-homo-aryl group or a C ₄ ~ C ₃₀ heteroaryl group (O) or sulfur (S), L ₁ and L ₂ each independently represent a C ₅ -C ₃₀ homoarylene group which is unsubstituted or substituted with a cyano group, a substituted A C ₄ -C ₃₀ heteroarylene group which is unsubstituted or substituted by cyano group, a C ₅ -C ₃₀ homoalkylarylene group which is unsubstituted or substituted by cyano group, a C ₄ -C ₃₀ aryl group which is unsubstituted or substituted by cyano group ₃₀ heteroalkyl arylene group, is optionally substituted with a cyano group-substituted C ₅ ~ C ₃₀ Homo aryloxy xylene group, an unsubstituted or substituted by a cyano group, C ₄ ~ C ₃₀ heteroaryloxy xylene group, an unsubstituted or substituted by a cyano group A C ₅ to C ₃₀ homoarylene amine group and a C ₄ to C ₃₀ heteroarylene amine group unsubstituted or substituted with a cyano group; a, b, and c are each independently 0 or 1; )

According to another aspect of the present invention, there is provided an organic light emitting diode and an organic light emitting diode display device in which the organic compound is applied to the organic light emitting layer.

In one example, the organic compound may be used as a host of the light emitting material layer.

The organic compound of the present invention is designed so that the difference between the singlet energy level and the triplet energy level, that is, the band gap energy exceeds 0.3 eV. In addition, the organic compound of the present invention has excellent heat resistance because it has at least one carbazole moiety and at least one dibenzofuran or dibenzothiophene moiety.

The organic compound according to the present invention has a relatively wide band gap as compared with the retarded fluorescent material, and the triplet energy level is higher than the triplet energy of the retarded fluorescent material. Therefore, when the organic compound according to the present invention is used as a host of the light emitting material layer, exciton extinguishing due to the interaction of the triplet / single-term exciton of the host and the hole (or electron) -polarolone in the periphery is minimized. Accordingly, the lifetime of the light emitting diode device can be prevented from being lowered by electro-oxidation and photo-oxidation, so that a long-life light emitting device can be realized.

In addition, since the organic compound of the present invention can efficiently transfer energy to the dopant without losing energy in the light emission process, high luminous efficiency can be achieved.

Accordingly, an organic light emitting diode having improved luminescence efficiency and device lifetime characteristics by using the organic compound of the present invention as a host of an organic light emitting layer constituting an organic light emitting diode and using a compound exhibiting delayed fluorescence characteristics as a dopant, Can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram for explaining a luminescent mechanism of a retarded fluorescent compound used together with an organic compound according to an exemplary embodiment of the present invention. Fig.
FIG. 2 is a graph showing the relationship between the exciton of a host having a narrow energy bandgap and the polaron of a surrounding region in a light emitting diode having a host used together with a conventional retardation fluorescent material. It is a schematic diagram.
FIG. 3 is a graph showing the relationship between the exciton of an energy bandgap-adjusted exciton of the host and the surrounding polaron in a light emitting diode using an organic compound synthesized in the present invention as a host together with a retarding fluorescent material according to an exemplary embodiment of the present invention. Is a schematic view for explaining a mechanism in which excitons of a host by action do not disappear.
4 is a cross-sectional view schematically showing an organic light emitting diode in which an organic compound is applied to an organic light emitting layer according to an exemplary embodiment of the present invention. For example, the organic compound according to the present invention is used in a layer of a light emitting material.
5 is a cross-sectional view schematically showing an organic light emitting diode in which an organic compound is applied to an organic light emitting layer according to another exemplary embodiment of the present invention, and schematically showing an organic light emitting diode having a charge blocking layer. For example, the organic compound according to the present invention is used in a layer of a light emitting material.
6 is a cross-sectional view schematically showing an organic light emitting diode display device as an example of a light emitting device having an organic light emitting diode in which an organic compound is applied to an organic light emitting layer according to an exemplary embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings where necessary.

[Organic compounds]

The organic compound used in the organic light-emitting diode has excellent luminescence characteristics and it is necessary to maintain stable characteristics by driving the device. The organic compound according to the present invention has such a characteristic. In the organic compound according to the present invention, the organic compound according to the present invention can be represented by the following formula (1).

Formula 1

Wherein R ₁ to R ₂₃ are each independently selected from the group consisting of hydrogen, deuterium, tritium, silyl groups, C ₁ to C ₂₀ alkyl groups, C ₁ to C ₂₀ alkoxy groups, C ₁ to C ₂₀ alkylamine groups, C ₅ ~ C ₃₀ Homo aryl group, C ₄ ~ C ₃₀ heteroaryl group, C ₅ ~ C ₃₀ Homo alkylaryl group, C ₄ ~ C ₃₀ heteroaryl-alkyl aryl group, C ₅ ~ C ₃₀ Homo aryloxy group, C ₄ ~ C ₃₀ heteroaryloxy group, C ₅ ~ C ₃₀ Homo arylamine group, a C ₄ ~ C ₃₀ heteroaryl amine group, or adjacent groups unsubstituted or combined substituted each other C ₅ ~ C _30-homo-aryl group or a C ₄ ~ C ₃₀ heteroaryl group (O) or sulfur (S), L ₁ and L ₂ each independently represent a C ₅ -C ₃₀ homoarylene group which is unsubstituted or substituted with a cyano group, a substituted A C ₄ -C ₃₀ heteroarylene group which is unsubstituted or substituted by cyano group, a C ₅ -C ₃₀ homoalkylarylene group which is unsubstituted or substituted by cyano group, a C ₄ -C ₃₀ aryl group which is unsubstituted or substituted by cyano group ₃₀ heteroalkyl arylene group, is optionally substituted with a cyano group-substituted C ₅ ~ C ₃₀ Homo aryloxy xylene group, an unsubstituted or substituted by a cyano group, C ₄ ~ C ₃₀ heteroaryloxy xylene group, an unsubstituted or substituted by a cyano group A C ₅ to C ₃₀ homoarylene amine group and a C ₄ to C ₃₀ heteroarylene amine group unsubstituted or substituted with a cyano group; a, b, and c are each independently 0 or 1; )

As used herein, "unsubstituted" or "unsubstituted" means that a hydrogen atom is substituted, in which case the hydrogen atom includes hydrogen, deuterium, and tritium.

As used herein, the substituent in the term "substituted" includes, for example, a C ₁ -C ₂₀ alkyl group which is unsubstituted or substituted by halogen, a C ₁ -C ₂₀ alkoxy group which is unsubstituted or substituted by halogen, halogen, cyano group, -CF _3, a hydroxy group, a carboxy group, a carbonyl group, an amine group, C ₁ ~ C ₁₀ alkyl substituted amine group, C ₅ ~ C ₃₀ aryl substituted amine group, a C ₄ ~ C ₃₀ heteroaryl group substituted with an amine group, a nitro group, a hydrazide chewy a C ₁ to C ₂₀ alkylsilyl group, a C ₁ to C ₂₀ alkoxysilyl group, a C ₃ to C ₃₀ cycloalkylsilyl group, a C ₅ to C ₃₀ arylsilyl group, a C ₄ to C ₃₀ silyl group, A C ₅ -C ₃₀ aryl group, a C ₄ -C ₃₀ heteroaryl group, and the like, but the present invention is not limited thereto. For example, when R < ₅ > and / or R < ₆ > in the formula (1) are substituted with alkyl groups, the alkyl group may be a linear or branched C ₁ -C ₂₀ , preferably C ₁ -C ₁₀ alkyl group.

The terms "heteroaromatic ring", "heterocycloalkylene group", "heteroarylene group", "heteroarylalkylene group", "heteroaryloxylene group", "heterocycloalkyl group", "heteroaryl group", " The term "hetero" as used in heteroarylalkyl group, heteroaryloxyl group and heteroarylamine group means that at least one of the carbon atoms constituting these aromatic or alicyclic rings, Means that one to five carbon atoms are replaced by one or more heteroatoms selected from the group consisting of N, O, S, and combinations thereof.

As shown in Formula 1, the organic compound according to the present invention has at least one carbazole moiety and a dibenzofuran or dibenzothiophene moiety. At this time, at least one carbazole moiety has a p-type property because of its excellent ability to bond to holes, and dibenzofuran / dibenzothiophene moiety has a relatively excellent ability to bond with electrons, Type property. Therefore, the organic compound represented by Formula 1 may have bi-polar properties.

In one exemplary embodiment, R ₁ to R ₂₃ each independently may be hydrogen, deuterium, or tritium. In another exemplary embodiment, R ₁ to R ₂₃ are each independently a C ₁ to C ₂₀ , preferably C ₁ to C ₂₀ straight or branched alkyl group or C ₁ to C ₂₀ , preferably C ₁ to C ₂₀ Alkoxy group. In another exemplary embodiment, R ₁ to R ₂₃ each independently may be an aromatic substituent. For example, when R ₁ to R ₂₃ are C ₅ to C ₃₀ homoaryl groups, R ₁ to R ₂₃ each independently represent a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, an anthracenyl group, a pentanenyl group, A benzenesulfonyl group, a benzenesulfonyl group, an azulenyl group, a pyrenyl group, a fluoranethenyl group, a benzenesulfonyl group, a benzenesulfonyl group, a benzenesulfonyl group, Condensation such as a triphenylene group, a triphenyl group, a triphenyl group, a triphenyl group, a triphenyl group, a triphenyl group, a triphenyl group, a triphenyl group, a triphenyl group, a triphenyl group, Or may be a fused aryl group.

In an alternative embodiment, when R ₁ to R ₂₃ are C ₄ to C ₃₀ heteroaryl groups, R ₁ to R ₂₃ each independently represent a pyrrolyl group, a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group A thiazolyl group, a tetrazinyl group, an imidazolyl group, a pyrazolyl group, an indolyl group, an isoindolyl group, an indazolyl group, an indolizinyl group, a pyrrolidinyl group, a carbazolyl group, a benzocarbazolyl group, A thiazolyl group, an indolocarbazolyl group, an indenocarbazolyl group, a benzofurocarbazolyl group, a benzothienocarbazolyl group, a quinolinyl group, an isoquinolinyl group, a phthalazinyl group, a quinoxalinyl group, , A quinazolinyl group, a quinolizinyl group, a quinolizinyl group, a purinyl group, a phthalazinyl group, a quinoxalinyl group, a benzoquinolinyl group, a benzoisoquinolinyl group, a benzoquinazolinyl group, a benzoquinoxalinyl group, , Phenanthrolinyl group, perimidinyl group, phenanthridinyl group, phthalidinyl group, cinol A thiazolyl group, a thiopyranyl group, a thiopyranyl group, a thiopyranyl group, a thiopyranyl group, a thiopyranyl group, a thiopyranyl group, a thiopyranyl group, a thiopyranyl group, A thiophene group, a benzothiophenyl group, a dibenzothiophenyl group, a difluoropyrazinyl group, a benzofurodibenzofuranyl group, A non-condensed or condensed heteroaryl group such as a benzothiophenyl group, a benzothienobenzofuranyl group, a benzothienodibenzofuranyl group, or an N-substituted spirobifluorenyl group.

In one exemplary embodiment, when R ₁ to R ₂₃ are a homoaryl group or a heteroaryl group, preferably these homoaryl groups or heteroaryl groups may consist of one to two aromatic rings. When the number of aromatic rings constituting R ₁ to R ₂₃ is increased, the conjugated structure in the entire organic compound becomes excessively long, so that the bandgap of the organic compound can be excessively reduced. For example, R ₁ to R _{23 each} independently represent a phenyl group, a biphenyl group, a pyrrolyl group, a triazinyl group, an imidazolyl group, a pyrazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, A furanyl group, a dibenzofuranyl group, a thiophenyl group, a benzothiophenyl group or a dibenzothiophenyl group.

In another alternative embodiment, R ₁ to R ₂₃ may combine with adjacent groups to form a condensed ring which is unsubstituted or substituted with a C ₅ -C ₃₀ homoaryl group or a C ₄ -C ₃₀ heteroaryl group. When R ₁ to R ₂₃ combine with adjacent groups to form a condensed ring, the C ₅ -C ₃₀ homoaryl group or the C ₄ -C ₃₀ heteroaryl group which may be substituted in the condensed ring is one or two aromatic rings , And a band gap energy suitable for use in the light emitting layer. Accordingly, when R ₁ to R ₂₃ combine with adjacent groups to form a condensed ring, the aromatic substituent which can be substituted in the newly formed condensed ring is preferably a phenyl group, a biphenyl group, a pyrrolyl group, an imidazolyl group, a pyrazolyl group, , A pyridinyl group, a pyrimidinyl group, a pyridazinyl group, a furanyl group or a thiophenyl group, preferably a phenyl group.

As described above, R ₁ to R ₂₃ may combine with adjacent groups to form a condensed ring which is unsubstituted or substituted with an aromatic ring. For example, when R ₁ to R ₁₆ constituting the carbazole moiety are each independently joined to adjacent groups to form a condensed ring, the carbazole moiety is not each substituted or a C ₁ to C ₂₀ linear or branched alkyl group, Preferably a C ₁ to C 10 linear or branched alkyl group, a C ₅ to C ₃₀ homoaryl group, preferably a C ₅ to C ₁₀ homoaryl group, a C ₄ to C ₃₀ heteroaryl group, preferably a C ₄ to C ₁₀ hetero (S) selected from the group consisting of benzocarbazole, dibenzocarbazole, benzofurocarbazole, benzothiophenecarbazole and benzothiophene substituted with at least one functional group selected from the group consisting of an aryl group, benzothienocarbazole, indenocarbazole, indolocarbazole, and the like, but the present invention is not limited thereto.

On the other hand, when R ₁₇ to R ₂₃ constituting the dibenzofuran / dibenzothiophene moiety are combined with adjacent groups to form a condensed ring, the dibenzofuran or dibenzothiophene moiety is not each substituted, or C ₁ ~ C ₂₀ straight or branched alkyl group, preferably a C1 ~ C10 linear or branched alkyl group, a C ₅ ~ C ₃₀ Homo aryl group, preferably a C ₅ ~ C ₁₀ Homo aryl group, C ₄ ~ C ₃₀ heteroaryl group, preferably , Pyridodibenzofuran, pyridodibenzothiophene, indenodiaryl, and the like, which are substituted with at least one functional group selected from the group consisting of C ₄ to C ₁₀ heteroaryl groups and combinations thereof, Indenodibenzofuran, indenodibenzothiophene, indolodibenzofuran and / or indolodibenzothiophene. However, the present invention is not limited to this. Do not.

In formula (1), L ₁ and L ₂ are linkers that mediate a carbazole moiety having a p-type property and a dibenzofuran or dibenzothiophene moiety having an n-type property, respectively. For example, L ₁ and L ₂ may each independently be an aromatic linking group such as a C ₅ -C ₃₀ homoarylene group or a C ₄ -C ₃₀ heteroarylene group. For example, when L ₁ and L ₂ are C ₅ to C ₃₀ arylene groups, L ₁ and L ₂ are each independently a phenylene, biphenylene, or biphenylene group which is unsubstituted or substituted with a cyano group, And examples thereof include terphenylene, tetraphenylene, indenylene, naphthylene, azulenylene, indacenylene, acenaphthylene, A fluorenylene group, a spiro-fluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluororanthrenylene group, a triphenylene group, a phenanthrenylene group, And examples thereof include triphenylenylene, pyrenylene, chrysenylene, naphthacenylene, picenylene, perylenylene, pentaphenylene, and hexa In the group consisting of hexacenylene, It can be.

In another alternative embodiment, when L ₁ and L ₂ are C ₄ -C ₃₀ heteroarylene groups, L ₁ and L ₂ are independently selected from the group consisting of pyrrolylene, imidazole And examples thereof include imidazolylene, pyrazolylene, pyridinylene, pyrazinylene, pyrimidinylene, pyridazinylene, isoindolylene, Indolylene, indazolylene, purinylene, quinolinylene, isoquinolinylene, benzoquinolinylene, phthaloyl, and the like. There may be mentioned phthalazinylene, naphthyridinylene, quinoxalinylene, quinazolinylene, benzoquinolinylene group, benzoisoquinolinylene group, benzoquinazolinylene group, benzoquinazolinylene group, A quinoxalinylene group, a cinnoliny group phenanthridinylene, acridinylene, phenanthrolinylene, phenazinylene, benzoxazolylene, benzimidazolylene, benzimidazolyl, benzimidazolyl, benzimidazolyl, , Furanylene, benzofuranylene, thiophenylene, benzothiophenylene, thiazolylene, isothiazolylene, benzothiazolylene, benzothiophenylene, benzothiophenylene, The present invention relates to a process for the preparation of a compound of the formula (I) wherein R is a benzothiazolylene, isoxazolylene, oxazolylene, triazolylene, tetrazolylene, There can be mentioned dibenzofuranylene, benzofurodibenzofuranylene group, benzothienobenzofuranylene group, benzothienodibenzofuranylene group, benzothiophenylene group, dibenzothiophenylene group, benz A thiophene group, a thieno group, a thienyl group, a thienyl group, a thienyl group, a thienyl group, a thienyl group, a thienyl group, a thienyl group, a thienyl group, An imidazopyrimidinylene group, and an imidazopyridinylene group. The term " imidazopyrimidinylene group "

In one exemplary embodiment, if the number of aromatic rings constituting L ₁ and L ₂ is increased, the conjugated structure in the entire organic compound becomes excessively long, so that the energy band gap of the organic compound can be excessively reduced . Therefore, the number of aromatic rings constituting each of L ₁ and L ₂ is preferably 1 to 2, more preferably 1. Also, with respect to the injection and transport properties of holes or electrons, L ₁ and L ₂ can each be a 5-membered ring to a 7-membered ring, (6-membered ring). For example, L ₁ and L ₂ are each independently a substituted or unsubstituted phenylene group, biphenylene group, pyrrolylene group, imidazolylene group, pyrazolylene group, pyridinylene group, pyrazinylene group, pyrimidinyl group A phenylene group, a phenylene group, a phenanthrene group, a phenanthrene group, a phenanthrene group,

The organic compound represented by the formula (1) has a carbazole moiety having a p-type characteristic and a dibenzofuran or dibenzothiophene moiety having an n-type characteristic, and thus has an excellent affinity for holes and electrons Do. Therefore, when the organic compound represented by the general formula (1) is applied to the light emitting layer of the light emitting diode, a recombination zone in which holes and electrons form an exciton forms a light emitting material layer (EML) - an electron transporting layer (ETL) ), But in the central region of the light emitting material layer (EML).

Further, the organic compound represented by the formula (1) has a band gap energy (ΔE _ST ^H ) which is a difference between the singlet energy level (S1 ^H ) and the triplet energy level (T1 ^H ) of more than 0.3 eV. Since the excitons generated in the light emitting process of the organic compound represented by the formula (1) are not interacted with the hole (or electron) -polaron formed at the periphery thereof and are transferred to other adjacent molecules without interacting with each other, The luminescent energy generated at the time of forming may not contribute to the emission but may contribute to luminescence. Accordingly, the exciton generated from the organic compound represented by the formula (1) and the hole (electron) -polarone originating from the organic compound do not interact with each other, and the interaction of the exciton / hole (electron) Lt; / RTI > is prevented and the non-emission disappearance is reduced. Further, since the organic compound represented by the general formula (1) is not deteriorated by the heat generated by the driving of the light emitting element, the damage to the material is reduced and the lifetime of the element can be improved.

Therefore, the organic compound according to the present invention can be used as a host of an organic light emitting layer constituting an organic light emitting diode, and can be applied to a light emitting material layer using a so-called delayed florescence compound as a dopant. Explain.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram for explaining a luminescent mechanism of a retarded fluorescent compound used together with an organic compound according to an exemplary embodiment of the present invention. Fig. Delayed fluorescence can be classified into thermally activated delayed fluorescence (TADF) and field-activated delayed fluorescence (FADF), wherein triplet excitons are activated by heat or an electric field, So-called super-fluorescence exceeding the maximum luminous efficiency in the material can be realized.

That is, the retarded fluorescent compound is activated by the heat or electric field generated when the device is driven, so that the triplet exciton is also involved in the emission of the triplet exciton. Generally, a retarded fluorescent compound has both an electron donor moiety and an electron acceptor moiety so that an intramolecular charge transfer (ICT) state is possible. When a retarded fluorescent compound capable of ICT state is used as a dopant, an exciton having a singleton energy level (S ₁ ) and an exciton having a triplet energy level (T ₁ ) in a retarded fluorescent compound migrate to an intermediate ICT state, (S ₁ → ICT ← T ₁ ) to the ground state (S ₀ ). Since both the exciton having the singlet energy level (S ₁ ) and the exciton having the triplet energy level (T ₁ ) participate in the light emission, the internal quantum efficiency is improved and thus the light emission efficiency is improved.

Conventionally, since the fluorescent material has a highest occupied molecular orbital (HOMO) and a lowest unoccupied molecular orbital (LUMO) distributed throughout the molecule, It is impossible to switch between them (selection rule). However, since the compound having ICT state has a small overlap of HOMO and LUMO orbitals, the interaction between the HOMO state orbit and the LUMO state orbit is small. Therefore, the spin state change of the electrons does not affect other electrons, and a new charge transfer band (CT band) which does not follow the selection rule is formed.

That is, since the electron acceptor moiety and the electron donor moiety are spaced apart in the molecule in the retarded fluorescent compound, the dipole moment in the molecule is present in a highly polarized state. The interaction between the HOMO and the LUMO state orbitals is reduced in the state where the dipole moment is polarized, and the transition from the triplet state to the intermediate state (ICT) becomes possible, and the exciton of the singlet energy level (S ₁ ) Of course, all of the excitons of the triplet energy level (T ₁ ) participate in luminescence. That is, when the light emitting device is driven, an exciton having a singlet energy level (S ₁ ) of 25% and an exciton having a triplet energy level (T ₁ ) of 75% are converted into an intermediate state (ICT) Since the light emission occurs while falling back to the ground state S ₀ , the internal quantum efficiency is theoretically 100%.

The dopant and the host for implementing the delayed fluorescence need to have the following characteristics. The retarded fluorescent dopant must have an electron donor moiety and an electron acceptor moiety at the same time in one molecule, so that ICT can be realized. That is, in an ICT complex under certain conditions, one electron moves from the electron donor moiety to the electron acceptor moiety, resulting in the separation of charge in the molecule. In order to cause energy transfer in both the triplet state and the singlet state, the dopant capable of realizing retarded fluorescence has a difference (ΔE _ST ) between the singlet energy level (S ₁ ) and the triplet energy level (T ₁ ) of 0.3 eV, for example between 0.05 and 0.3 eV. In this way, compounds with low ΔE _ST exhibit fluorescence not only when inter-system crossing (ICS) occurs in which energy is transferred from a singlet state to a triplet state, but when heat energy at a room temperature level is applied, Reverse Inter System Crossing (RISC) occurs in a single energy state with a higher energy, and a delayed fluorescence is exhibited as a single phase state transitions to a bottom state. In the case of delayed fluorescence, efficiency of 100% at the theoretical maximum can be obtained, so that the internal quantum efficiency equivalent to that of a conventional phosphorescent material containing a heavy metal can be realized.

On the other hand, the host for implementing the delayed fluorescence should be able to induce excitons in the triplet state in the dopant to be involved in light emission without being quenched (non-quenching). FIG. 2 is a schematic diagram showing a non-luminescent annihilation mechanism caused by a small difference between a single-energy level and a triplet energy level of a host used together with a conventional retardation fluorescent material.

As shown in FIG. 2, the host for implementing the delayed fluorescence has to adjust the energy level with the dopant. First, the excitation state triplet energy level (T ₁ ^H ) of the host should be higher than the excited triplet energy level (T ₁ ^D ) of the retarded fluorescent dopant. If the excited state triplet energy level (T ₁ ^H ) of the host is not sufficiently higher than the excited triplet energy level (T ₁ ^D ) of the retarded fluorescent dopant, the excited triplet energy level of the retarded fluorescent dopant (T ₁ ^D ) Excites the triplet exciton to the excited state triplet energy level (T ₁ ^H ) of the host and the triplet exciton is non-emitively extinguished in the host where the triplet exciton is unable to emit, Of the triplet state excitons do not contribute to luminescence.

In addition, it is necessary to appropriately adjust the highest occupied molecular orbital (HOMO) energy level and the lowest unoccupied molecular orbital (LUMO) energy level of the host and the retardation fluorescent dopant. For example, the difference between the highest level occupied molecular orbital energy level (HOMO ^H ) of the host and the highest level occupied molecular orbital energy level (HOMO ^D ) of the retarded fluorescent dopant (| HOMO ^H -HOMO ^D | The difference (| LUMO ^H -LUMO ^D |) between the molecular orbital energy level (LUMO ^H ) and the lowest level non-occupied molecular orbital energy level (LUMO ^D ) of the retardation fluorescent dopant is 0.5 eV or less, for example, 0.1 to 0.5 eV May be preferred. As a result, the charge transfer efficiency from the host to the retarded fluorescent dopant is improved, and ultimately the luminous efficiency can be improved.

In addition, in order to ensure a sufficient lifetime of the light emitting device to which the retardation fluorescent dopant is applied, the exciton ^D of the dopant and the exciton quenching caused by the interaction of the peripheral hole- It is necessary to minimize electro-oxidation and / or photo-oxidation.

By the way, at the same time in a light emitting system using the conventional delay fluorescent dopant, a difference of singlet energy level (S ₁ ^D) and the triplet energy level (T ₁ ^D) of the delayed fluorescent dopant (ΔE _ST ^D) is 0.3 eV or less, the host (ΔE _ST ^H ) between the singlet energy level (S ₁ ^H ) and the triplet energy level (T ₁ ^H ) of 0.3 eV or less was also used. Accordingly, the singlet energy level (S ₁ ^D) and the triplet energy level (T ₁ ^D) the difference (ΔE _ST ^D) is less delayed fluorescent dopant singlet energy level (S ₁ ^D) between the by ISC and RISC And the triplet energy level (T ₁ ^D ), the dopant exciton ^D is continuously formed. The exciton ^D excites the phosphorescent dopant exciton ^D (excitation ^D ) and the host polaron (Host) generated when the emission is realized. However, the dopant exciton ^D rapidly participates in the light emission process , The non-luminescent extinction caused by the interaction of the dopant exciton ( ^D ) and the host polaron (Host) is negligible.

In addition, conventional hosts with a small difference (ΔE _ST ^H ) between singlet energy level (S ₁ ^H ) and triplet energy level (T ₁ ^H ) by ISC and RISC also have single energy level (S ₁ ^H ) And the triplet energy level (T ₁ ^H ), while continuously generating a host exciton ( ^H ). The energy of the continuously generated host exciton ( ^H ) is transferred to the dopant through the Foster energy transfer mechanism and the Dexter energy transfer mechanism. However, a portion of the singlet energy level (S ₁ ^H) and the triplet energy level (T ₁ ^H) difference (ΔE _ST ^H) is small, continuously host excitons (Excition ^H) generated in between, to implement a light emitting The generated host polaron (Host) interacts with the non-luminescent decay.

Due to the continuous interaction between the host exciton ( ^H ) and the host polaron (Host), degradation occurs in which part of the exciton ^H excitation energy is not transferred to the dopant. Therefore, the generation efficiency of the dopant exciton ^D decreases in the emission process by the delayed fluorescent dopant. As a result, not only the luminous efficiency of the light emitting device is lowered but also the non-light emission disappearance is increased, stress is applied to the material applied to the light emitting layer, causing damage, thereby reducing the lifetime of the device.

On the other hand, the organic compound synthesized according to the present invention may be intentionally designed to have a difference between a single-term energy level and a triplet energy level exceeding 0.3 eV, thereby improving the luminous efficiency and lifetime of the device. do. According to an exemplary embodiment of the present invention, the organic compound represented by the general formula (1) can be used as a host of a light emitting material layer, and a dopant having a delayed fluorescence property can be used. Due to the characteristics of the delayed fluorescent dopant, although the excitation ^{D of the} retarded fluorescent dopant generated in the light emission process and the host polaron (Host) generated in realizing the luminescence interact with each other, the light emission disappears , The non-emissive extinction caused by the interaction of the dopant excitons ( ^D ) and the host polaron (Host) is negligible. On the other hand, the organic compound represented by general formula (1) is in excess of the difference is 0.3 eV (ΔE _ST ^H) between the singlet energy level (S ₁ ^H) and the triplet energy level (T ₁ ^H). In one example, the organic compound represented by the formula (I) is the difference (ΔE _ST ^H) between the singlet energy level (S ₁ ^H) and the triplet energy level (T ₁ ^H) greater than the 0.3 eV and 1.5 eV or less, and preferably May be greater than 0.3 eV and less than 1.0 eV. Therefore, the organic compound represented by the formula (1) singlet from the singlet energy level triplet energy level (T ₁ ^H) can move, the triplet energy level (T ₁ ^H) but from (S ₁ ^H), by ISC RISC to the energy level (S ₁ ^H ) is impossible.

Since the host excitons generated by the ISC are directly transferred to the dopant through the Foster energy and the Dexter mechanism, a part of the generated host exciton (Excition ^H ) and a host polaron (Host) generated when the luminescence is realized It does not interact. Therefore, all of the generated exciton ^H excitation energy is transferred to the dopant, and the efficiency of generating the dopant exciton ^D can be improved in the emission process by the delayed fluorescent dopant. Thus, not only the luminous efficiency of the light emitting device is lowered but also the damage due to the stress applied to the material applied to the light emitting layer is reduced while the non-light emitting extinction is reduced, thereby increasing the lifetime of the device.

In the organic compound according to the present invention, any one of the linking groups (L ₁ and L ₂ ) may be substituted with a cyano group (-CN) having an excellent electron attracting property. Accordingly, the organic compound of the present invention has an amphoteric characteristic, has a wide band gap, and has a high triplet energy level (T ₁ ^H ) in an excited state, so that it is suitable for use as a host of an organic light emitting layer Do. That is, when the organic compound according to the present invention is used as a host for the organic light emitting layer, the exciton of the excited triplet energy level (T ₁ ^D ) of the retarded fluorescent dopant is inversely related to the triplet energy level (T ₁ ^H ) The charge transfer is suppressed and the excitons generated in the host are transferred to the dopant without non-emission disappearance, thereby improving the luminous efficiency and improving the lifetime of the device. Further, by introducing a cyano group, blue shift can be realized with excellent color purity.

In one exemplary embodiment, the organic compound according to the present invention comprises a compound represented by the following formula (2a) or (2b).

Formula 2a

2b

(Wherein, X, a, b and c are each as defined in formula (1), R ₃₁ to R ₃₈ are each independently hydrogen, deuterium, tritium, Wherein the aromatic ring is selected from the group consisting of a phenyl group, a biphenyl group, a pyrrolyl group, a triazinyl group, an imidazolyl group, a pyrazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, R ₄₁ and R ₄₂ are each independently selected from the group consisting of hydrogen, deuterium, tritium, or cyano group), a benzyl group,

More specifically, the organic compound according to the present invention may be any compound represented by the following general formula (3).

(3)

Since the organic compound represented by the general formula (2a), (2b) or (3) has a large difference between the triplet energy level and the single-energy level, the excitons generated in the light emission process are not non- . Accordingly, when the organic compound represented by the general formula (2a), (2b) or (3) is used in the organic light emitting layer of the light emitting device, the light emitting efficiency can be improved. The exciton quenching due to the interaction between the host exciton and the surrounding polaron is minimized and the lifetime of the light emitting diode device due to electro-oxidation and photo-oxidation can be prevented from being lowered. Further, the organic compound of the present invention is excellent in heat resistance, high in energy band gap and triplet energy level, and excellent in color purity because it is substituted with cyano group when necessary. That is, when the organic compound of the general formula (2a), (2b) or (3) is used as a host of the light emitting material layer, energy can be efficiently transferred to the dopant, have. In addition, damage to the material applied to the light emitting material layer is reduced, so that a light emitting device with a long life can be manufactured, and a light emitting device having excellent color purity can be realized.

[Organic light emitting diode and organic light emitting diode display device]

As described above, the organic compounds represented by the general formulas (1) to (3) are used as the light emitting material in the organic light emitting layer constituting the organic light emitting diode, so that the light emitting device having good color purity and improved light emitting efficiency and device life characteristics have. This will be described. 4 is a cross-sectional view schematically showing an organic light emitting diode in which an organic compound is applied to an organic light emitting layer according to an exemplary embodiment of the present invention.

4, the organic light emitting diode 100 according to the first embodiment of the present invention includes a first electrode 110 and a second electrode 120 facing each other, a first electrode 110 and a second electrode 110, And 120, respectively. In the exemplary embodiment, the organic light emitting layer 130 includes a hole injection layer (HIL) 140, a hole transfer layer (HTL) 150, and a light emitting material layer 140 sequentially stacked from the first electrode 110. An emissive material layer (EML) 160, an electron transfer layer (ETL) 170, and an electron injection layer (EIL) 180.

The first electrode 110 may be an anode for supplying holes to the light emitting material layer 160. The first electrode 110 is preferably formed of a conductive material having a relatively large work function value, for example, a transparent conductive oxide (TCO). For example, the first electrode 110 may be formed of indium-tin-oxide (ITO), indium-zinc-oxide (IZO), indium-tin- (ITO), tin oxide (SnO), zinc oxide (ZnO), indium-copper-oxide (ICO) and aluminum: Al: ZnO have.

The second electrode 120 may be a cathode for supplying electrons to the light emitting material layer 160. The second electrode 120 may have a reflective property such as a conductive material having a relatively low work function value, for example, aluminum (Al), magnesium (Mg), calcium (Ca), silver (Ag) It can be made of good material.

The hole injection layer 140 is located between the first electrode 110 and the hole transport layer 150 and improves the interface characteristics between the first electrode 110 as an inorganic material and the hole transport layer 150 as an organic material. In one exemplary embodiment, the hole injection layer 140 is formed of a mixture of 4,4 ', 4 "-tris (3-methylphenylamino) triphenylamine (4,4', 4" -tris (3-methylphenylamino) triphenylamine; MTDATA), copper phthalocyanine (CuPc), tris (4-carbazoyl-9-yl-phenyl) amine (TCTA), N, N'-diphenyl N, N'-bis (1-naphthyl) -1, 1 '-biphenyl-4,4'- NPB), 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (1, 4, 5, 8, 9, 11- hexaazatriphenylenehexacarbonitrile (HAT-CN), 1,3,5-tris [4- (diphenylamino) phenyl] benzene, 1,3,5- PEDOT / PSS) and / or N- (biphenyl-4-yl) -9,9-dimethyl-N- (4-ethylenedioxythiophene) polystyrene sulfonate (9-phenyl-9H-carbazol-3-yl) phenyl) -9H-fluorene- -phenyl-9H -carbazol-3-yl) phenyl) -9H-fluoren-2-amine) and the like. Depending on the characteristics of the organic light emitting diode 100, the hole injection layer 140 may be omitted.

The hole transport layer 150 is disposed adjacent to the light emitting material layer 160 between the first electrode 110 and the light emitting material layer 160. In one exemplary embodiment, the hole transport layer 150 is formed from N, N'-diphenyl-N, N'-bis (3-methylphenyl) -1,1'-biphenyl-4,4'- TPD), NPD, 4,4'-bis (N-carbazolyl) - N'-diphenyl- Bis (N-carbazolyl) -1,1'-biphenyl (CBP), 1,3-bis (N-carbazolyl) benzene -carbazolyl) benzene, mCP), N- (biphenyl-4-yl) -9,9-dimethyl-N- (4- (9-phenyl-9H-carbazol-3-yl) phenyl) -9H-fluoren-2-amine ) And / or N- (biphenyl-4-yl) -N- (4- (9-phenyl-9H-carbazol- -yl) -N- (4- (9-phenyl-9H-carbazol-3-yl) phenyl) biphenyl-4-amine), but the present invention is not limited thereto.

The light emitting material layer 160 may be formed by doping a host with a dopant. For example, the light emitting material layer 160 may be doped with about 1 to 30% by weight of a dopant to the host, and emit blue light.

The organic compound represented by the general formulas (1) to (3) may be used as a host of the light emitting material layer 160. On the other hand, the dopant used for the light emitting material layer 160 may be a dopant having a retardation fluorescent property.

As described above, a compound having a retarded fluorescence characteristic is activated by heat or an electric field and has an intermediate energy state such as an ICT complex form. Both the exciton having the single-energy level and the exciton having the triplet energy level are involved in the light emission, so that the light-emitting efficiency of the organic light-emitting diode 100 can be improved.

3, when the difference (ΔE _ST ^D ) between the excited single-state energy level (S ₁ ^D ) and the excited triplet energy level (T ₁ ^D ) of the dopant is 0.3 eV or less, these energy levels To the intermediate energy state, and finally to the bottom state, the quantum efficiency of the dopant can be improved. That is, as ΔE _ST ^D becomes smaller, the luminous efficiency can be increased and the difference (ΔE _ST ^D ) between the excited single-state energy level (S ₁ ^D ) and the excited triplet energy level (T ₁ ^D ) eV, the singlet-state exciton and the triplet state exciton can be transferred to an intermediate ICT complex state by heat or an electric field.

In order to maximize the luminous efficiency due to the delayed fluorescence, the excited triplet energy level (T ₁ ^H , see FIG. 3) of the organic compound represented by the general formulas (1) to (3) Should be higher than the excited state triplet energy level of the compound (T ₁ ^D , see FIG. 3). In particular, the difference between the highest level occupied molecular orbital energy level (HOMO ^H ) of the host and the highest level occupied molecular orbital energy level (HOMO ^D ) of the dopant (| HOMO ^H -HOMO ^D |) or host's lowest level ratio occupied molecular orbital energy minimum level difference between the level unoccupied molecular orbital energy level (LUMO ^D) of (LUMO ^H) and dopant (| LUMO ^H -LUMO ^D |) is to not more than 0.5 eV, as a dopant in the host, energy is efficiently transmitted to the light-emitting efficiency Can be maximized.

According to one exemplary embodiment, when the organic compound represented by any one of Chemical Formulas 1 to 3 is used as a host of the light emitting material layer 160, a dopant suitable for the energy level with respect to the host may be used Lt; / RTI > For example, the retarded fluorescent dopant can be a retarded fluorescent dopant that emits blue light. To achieve a level of blue emission applicable to a display device, the excited state singlet energy level (S ₁ ^D ) of the retarded fluorescent dopant can be at a level of 2.7 to 2.8 eV, and the excited state triplet energy level (T ₁ ^D ) may be 2.4 to 2.5 eV or more, but the present invention is not limited thereto.

The blue light-emitting retardant fluorescent dopant which can be used as a dopant of the light emitting material layer 160 according to the exemplary embodiment of the present invention may be made of any one material represented by the following formula (4).

Formula 4

In an exemplary embodiment, the retarded fluorescent dopant that may be used in the light emissive material layer 160 is 10- (4- (4,6-diphenyl-1,3,5-triazin-2-yl) phenyl) -9 9,9-dimethyl-9,9-dimethyl-9,10-dihydroacridine (10- (4- (4,6-diphenyl-1,3,5-triazin- (9,9-dimethyl-9,10-dihydroacridine), 10,10 '- (4,4'-sulfonylbis (9,9-dimethyl-9,10-dihydroacridine), DMAC-DPS), 10-phenyl-10H, 10'H (10-phenyl-10H, 10'H-spiro [acridine-9,9'-anthracen] -10'-one, ACRSA) 3,6-dibenzoyl-4,5-di (1-methyl-9-phenyl-9H-carbamoyl) -9-phenyl-9H-carbazoyl) -2-ethynylbenzonitrile, CzPVP), 9,9 ', 9 "- (5- (4,6- ) Benzene-1,2,3-triyl) tris (9,9 ', 9 "- (5- (4,6-diphenyl-1,3,5-triazin- -1,2,3-triyl) tris (9H-carbazole), TcZTrz), 9,9 '- (5- (9,6-diphenyl-1,3,5-triazin-2-yl) -1,3-phenylene) bis (9H- diphenyl-1,3,5-triazin-2-yl) -1,3-phenylene) bis (9H-carbazole), DczTrz), 9,9 ' (9,9-carbazole) (9,9 ', 9 ", 9"' - (((4-fluorophenyl) 6-phenyl-1,3,5-triazine-2,4-diyl bis (benzene-5,3,1-triyl)) tetrakis (9H-carbazole, DDczTrz) Yl) phenyl) methanone (bis (4- (9H-3,9'-bicarbazol-9-yl) phenyl) methanone, CC2BP), 9 '- [4- -Diphenyl-1,3,5-triazin-2-yl) phenyl] -3,3 ", 6,6" -tetraphenyl-9,3'6'9 "-tur-9H-carbazole (9 '- [4- (4,6-diphenyl-1,3,5-triazin-2-yl) phenyl] -3,3,6,6-tetraphenyl- 6'-triazine-2-yl) phenyl] -9,3 ': 6' , 9 "-tur-9H-carbazole (9'- [4- (4,6-diphenyl-1,3,5-triazin- -ter-9H-carbazole, BCC-TPTA),

9,9 '- (4,4'-sulfonylbis (4,1-phenylene)) bis (3,6-dimethoxy-9H-carbazole) (4,6-dimethoxy-9H-carbazole), DMOC-DPS), 9- (4- Phenyl) -3 ', 6'-diphenyl-9H-3,9'-bicycarbazole (9- (4- (4,6-diphenyl- 1,3,5-triazin- Diphenyl-9H-3,9'-bicarbazole, DPCC-TPTA), 10- (4,6-diphenyl-1,3,5-triazin- Phenoxazine, Phen-TRZ), 9- (4- (4,6-diphenyl-1,3-dioxolan- Yl) phenyl) -9H-carbazole (9- (4- (4,6-diphenyl-1,3,5-triazin- -Ph-TRZ), 1,2,3,5-tetrakis (3,6-carbazol-9-yl) -4,6-dicyanobenzene (1,2,3,5-Tetrakis -carbazol-9-yl) -4,6-dicyanobenzene, 4CzIPN), 2,3,4,6-tetra (9H-carbazol- 5-fluorobenzonitrile, 4CZFCN), and / or 10- (4- (4,6-diphenyl-1,3,5-triazin- ) -10H-spiro [acridine-9,9'-fluorene] (10- (4- ( 3-diphenyl-1,3,5-triazin-2-yl) phenyl) -10H-spiro [acridine-9,9'-fluorene], SpiroAC-TRZ) no.

For example, the dopant, which may be a retardation fluorescent dopant, may be added in a proportion of 1 to 50 wt% in the light emitting material layer 160, but the present invention is not limited thereto.

An electron transport layer 170 and an electron injection layer 180 may be sequentially stacked between the light emitting material layer 160 and the second electrode 120. The material forming the electron transport layer 170 requires high electron mobility and stably supplies electrons to the light emitting material layer 160 through smooth electron transport.

In one exemplary embodiment, the electron transporting layer 170 may comprise at least one of oxadiazole, triazole, phenanthroline, benzoxazole, benzothiazole, benzimidazole, , Triazine, and the like.

For example, the electron transport layer 170 may be formed of tris (8-hydroxyquinoline aluminum; Alq ₃ ), 2-biphenyl-4-yl-5- (4- ), 1,3,4-oxadiazole (PBD), spiro-PBD, lithium quinolate ( lithium quinolate (Liq), 2- [4- (9,10-di-2-naphthalenyl-2-anthracenyl) phenyl] (2-methyl-8-quinolinolato-N1, O8) - (1, 1'-bipyridyl) Aluminum (BAlq), 3- (biphenyl-4-yl) aluminum (Bis-2- (4-tert-butylphenyl) -4-phenyl-4H-1,2,4-triazole 4,4-diphenyl-1,10-phenanthroline (Bphen), tris (phenylquinoxaline) (tris phenylquinoxaline (TPQ), and / or 1,3,5-tris (N-phenylbenzimide (N-phenylbenzimidazole-2-yl) benzene (TPBi), but the present invention is not limited thereto.

The electron injection layer 180 is located between the second electrode 120 and the electron transport layer 170 and improves the characteristics of the second electrode 120 to improve the lifetime of the device. In one exemplary embodiment, the material of the electron injection layer 180 may be an alkali halide based material such as LiF, CsF, NaF, BaF ₂ , and / or lithium quinolate (Liq), lithium benzoate, An organic metal-based material such as sodium stearate may be used, but the present invention is not limited thereto.

The organic light emitting diode 100 according to the exemplary embodiment of the present invention has a dopant having a retardation fluorescent property in the light emitting material layer 160 constituting the organic light emitting layer 130. [ Since both the singlet energy state and the triplet energy state excitons are involved in the light emission, the light emission efficiency is improved. In addition, the light emitting material layer 160 includes a host made of an organic compound represented by Chemical Formulas 1 to 3.

The organic compounds represented by the general formulas (1) to (3) have bonding and transporting properties to both holes and electrons. The organic compounds represented by the general formulas (1) to (3) have a wide energy band gap and a high excited triplet energy level (T ₁ ^H ). When the organic compound represented by the general formulas (1) to (3) is used as the host of the light emitting material layer, the exciton production efficiency of the dopant is improved while the generated exciton is transferred to the dopant without disappearing due to the interaction of the polaron . The damage to the light emitting material caused by the non-emission disappearance is reduced, and the organic compounds represented by the general formulas (1) to (3) have excellent heat resistance characteristics, so that the lifetime of the device can be improved. If necessary, the organic compound represented by any one of formulas (1) to (3) is substituted with at least one cyano group, so that light emission with high color purity can be realized while blue cyan is performed.

Meanwhile, the organic light emitting diode according to the present invention may further include at least one exciton blocking layer. 5 is a cross-sectional view schematically showing an organic light emitting diode to which a phosphorescent compound is applied according to a second exemplary embodiment of the present invention. 5, the organic light emitting diode 200 according to the second embodiment of the present invention includes a first electrode 210 and a second electrode 220 facing each other, a first electrode 210 and a second electrode 210 And 220, respectively.

In the exemplary embodiment, the organic light emitting layer 230 includes a hole injection layer 240, a hole transport layer 250, a light emitting material layer 260, an electron transport layer 270, and an electron transport layer 270 sequentially stacked from the first electrode 210. And an injection layer 280. The organic light emitting layer 230 may include an electron blocking layer (EBL) 255 and / or a light emitting material layer 260, which is a first exciton blocking layer positioned between the hole transporting layer 250 and the light emitting material layer 260. And a hole blocking layer (HBL) 265 which is a second exciton blocking layer positioned between the electron transport layer 270 and the electron transport layer 270.

As described above, the first electrode 210 may be an anode, and may be made of ITO, IZO, ITZO, SnO, ZnO, ICO, AZO, or the like, which is a conductive material having a relatively large work function value. The second electrode 220 may be a negative electrode and may be made of a conductive material having a relatively low work function value such as Al, Mg, Ca, Ag, or an alloy or combination thereof.

The hole injection layer 240 is located between the first electrode 210 and the hole transport layer 22. The hole injection layer 240 may include at least one of MTDATA, CuPc, TCTA, NPB, HAT-CN, TDAPB, PEDOT / PSS and / Phenyl) -9H-fluorene-2-amine, and the like. The hole injection layer 240 may be omitted depending on the characteristics of the organic light emitting diode 200.

The hole transport layer 250 is positioned adjacent to the light emitting material layer 260 between the first electrode 210 and the light emitting material layer 260. The hole transport layer 250 is formed of TPD, NPD, CBP, mCP, N- (biphenyl-4-yl) -9,9- Phenyl) -9H-fluorene-2-amine and / or N- (biphenyl-4-yl) -N- 4-amine. ≪ / RTI >

The light emitting material layer 260 may be formed by doping a host with a dopant. As an example, the light emitting material layer 260 may be doped with about 1 to 50% by weight of a dopant to the host, and may emit blue light. For example, when the organic compound represented by any one of Chemical Formulas 1 to 3 is used as a host of the light emitting material layer 260 and a compound exhibiting delayed fluorescence properties, for example, any compound represented by Chemical Formula 4, for example, DMAC- TRZ, DMAC-DPS, ACRSA, Cz-VPN, TcZTrz, DczTrZ, DDczTrZ, CC2BP, BDPCC-TPTA, BCC-TPTA, DMOC-DPS, DPCC- A compound such as SpiroAC-TRZ can be used as a dopant.

The electron transport layer 270 is located between the light emitting material layer 260 and the electron injection layer 280. For example, the electron transport layer 270 may be formed of a material selected from the group consisting of oxadiazole, triazole, phenanthroline, benzoxazole, benzothiazole, benzimidazole, Derivative. For example, the electron transport layer 270 can be formed of Alq ₃ , PBD, spiro-PBD, Liq, 2- [4- (9,10- Phenyl-1H-benzimidazole, BAlq, TAZ, Bphen, TPQ, and / or TPBi, but the present invention is not limited thereto.

The electron injection layer 280 is located between the second electrode 220 and the electron transport layer 270. As the material of the electron injection layer 280, an organic metal-based material such as an alkali halide-based material such as LiF, CsF, NaF, BaF ₂ and / or Liq, lithium benzoate), sodium stearate, But is not limited thereto.

On the other hand, when the holes move to the second electrode 220 through the light emitting material layer 260 or electrons travel to the first electrode 210 through the light emitting material layer 260, Can be imported. In order to prevent this, the organic light emitting diode 200 according to the second exemplary embodiment of the present invention includes at least one exciton blocking layer adjacent to the light emitting material layer 260.

For example, the organic light emitting diode 200 according to the second embodiment of the present invention includes an electron blocking layer (not shown) capable of controlling the movement of electrons between the hole transport layer 250 and the light emitting material layer 260, layer, EBL, 255).

For example, the electron blocking layer 255 may comprise at least one of TCTA, tris [4- (diethylamino) phenyl] amine, N- (biphenyl- Phenyl-9H-fluorene-2-amine, tri-p-tolylamine, 1-dimethyl-N- Bis (4- (N, N'-di (p-tolyl) amino) phenyl) cyclohexane; TAPC ), MTDATA, mCP, 3,3'-bis (N-carbazolyl) -1,1'-biphenyl, mCBP, TPD , CuPC, N, N'-bis [4- [bis (3-methylphenyl) amino] phenyl] -N, N'- diphenyl- [1,1'- biphenyl] -4,4'-diamine Diamine DNTPD) and / or TDAPB (N-diphenyl-N'-diphenyl- [1,1'-biphenyl] -4,4'- ≪ / RTI >

A hole blocking layer 265 is disposed as a second exciton blocking layer between the light emitting material layer 260 and the electron transporting layer 270 to prevent movement of holes between the light emitting material layer 260 and the electron transporting layer 270. do. In one exemplary embodiment, oxadiazole, triazole, phenanthroline, benzoxazole, benzoquinone, and the like, which can be used for the electron transport layer 270 as the material of the hole blocking layer, Benzothiazole, benzimidazole, triazine and the like can be used.

For example, the hole blocking layer 265 has a higher occupied molecular orbital (HOMO) energy level than the material used for the light emitting material layer 260, 4-diphenyl-1,10-phenanthroline (BCP), BAlq, Alq3, PBD, spiro-PBD, Liq and / or bis- Bis-4,6- (3,5-di-3-pyridylphenyl) -2-methylpyrimidine (B3PYMPM) have.

Since the organic light emitting diode 200 according to the second embodiment of the present invention has the dopant having the retardation fluorescence characteristic in the light emitting material layer 260, the light emitting efficiency is improved. In addition, the light emitting material layer 260 includes a host made of the organic compound represented by the general formulas (1) to (3).

The organic compounds represented by the general formulas (1) to (3) are amphoteric compounds and have an energy band gap and a high triplet energy level. When the organic compound represented by the general formulas (1) to (3) is used as the host of the light emitting material layer, the host exciton is transferred as a dopant without non-luminescence disappearance, the luminous efficiency is improved, - It is possible to increase the lifetime of the light emitting device while reducing damage to the light emitting material by oxidation. In addition, since a cyano group substituent can be optionally provided, light emission with high color purity can be realized.

In addition, since the organic light emitting diode 200 according to the second embodiment of the present invention includes at least one exciton blocking layer 255 and 265, the charge transporting layer 250 and 270 adjacent to the light emitting material layer 260, It is possible to further improve the luminous efficiency and the device life of the organic light emitting diode 200. [0070]

The organic light emitting diode according to the present invention can be applied to an organic light emitting diode display device or an organic light emitting device such as an illumination device to which the organic light emitting diode is applied. A display device to which the above-described organic light emitting diode is applied will be described as an example of the organic light emitting device according to the present invention. 6 is a schematic cross-sectional view of an organic light emitting diode display device according to an exemplary embodiment of the present invention.

6, the organic light emitting diode display 300 includes a driving thin film transistor Td as a driving element, a planarization layer 360 covering the driving thin film transistor Td, And an organic light emitting diode 400 connected to a driving thin film transistor Td as a driving element. The driving thin film transistor Td includes a semiconductor layer 310, a gate electrode 330, a source electrode 352 and a drain electrode 354. In FIG. 3, the driving thin film transistor Td includes a driving thin film of a coplanar structure And a transistor Td.

The substrate 302 may be a glass substrate, a thin flexible substrate, or a polymeric plastic substrate. For example, the flexible substrate may be formed of a material such as polyimide (PI), polyethersulfone (PES), polyethylene naphthalate (PEN), polyethylene terephthalate (PET) and polycarbonate (PC) As shown in FIG. The driving thin film transistor Td as the driving element and the substrate 302 on which the organic light emitting diode 400 is located constitute an array substrate.

A semiconductor layer 310 is formed on the substrate 302. For example, the semiconductor layer 310 may be made of an oxide semiconductor material. In this case, a light shielding pattern (not shown) and a buffer layer (not shown) may be formed under the semiconductor layer 310. The light shielding pattern prevents light from being incident on the semiconductor layer 310, Thereby preventing deterioration of the semiconductor device. Alternatively, the semiconductor layer 310 may be formed of polycrystalline silicon. In this case, impurities may be doped on both edges of the semiconductor layer 310.

A gate insulating layer 320 made of an insulating material is formed on the entire surface of the substrate 302 on the semiconductor layer 310. A gate insulating film 320 may be formed of an inorganic insulating material such as silicon oxide (SiO ₂₎ or silicon nitride (SiNx).

A gate electrode 330 made of a conductive material such as metal is formed on the gate insulating layer 320 to correspond to the center of the semiconductor layer 310. A gate line (not shown) and a first capacitor electrode (not shown) may be formed on the gate insulating layer 320. The gate wiring may extend along the first direction, and the first capacitor electrode may be connected to the gate electrode 330. Although the gate insulating layer 320 is formed on the entire surface of the substrate 302, the gate insulating layer 320 may be patterned to have the same shape as the gate electrode 330.

An interlayer insulating film 340 made of an insulating material is formed on the entire surface of the substrate 302 on the gate electrode 330. The interlayer insulating film 340 may be formed of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiN x), or may be formed of an organic insulating material such as benzocyclobutene or photo-acryl have.

The interlayer insulating film 340 has first and second semiconductor layer contact holes 342 and 344 that expose upper surfaces on both sides of the semiconductor layer 310. The first and second semiconductor layer contact holes 342 and 344 are located apart from the gate electrode 330 on both sides of the gate electrode 330. Here, the first and second semiconductor layer contact holes 342 and 344 are also formed in the gate insulating film 320. Alternatively, when the gate insulating film 320 is patterned in the same shape as the gate electrode 330, the first and second semiconductor layer contact holes 342 and 344 are formed only in the interlayer insulating film 340.

A source electrode 352 and a drain electrode 354 made of a conductive material such as metal are formed on the interlayer insulating layer 340. A data line (not shown), a power line (not shown), and a second capacitor electrode (not shown) may be formed on the interlayer insulating layer 340 in the second direction.

The source electrode 352 and the drain electrode 354 are spaced apart from each other around the gate electrode 330 and connected to both sides of the semiconductor layer 310 through the first and second semiconductor layer contact holes 342 and 344, Contact. Although not shown, the data wiring extends along the second direction and intersects the gate wiring to define the pixel region, and the power wiring for supplying the high potential voltage is located apart from the data wiring. The second capacitor electrode is connected to the drain electrode 354 and overlaps the first capacitor electrode to form a storage capacitor with the dielectric layer between the first and second capacitor electrodes as a dielectric layer.

The semiconductor layer 310, the gate electrode 330, the source electrode 352, and the drain electrode 354 constitute a driving thin film transistor Td. The driving thin film transistor Td illustrated in FIG. 6 has a coplanar structure in which the gate electrode 330, the source electrode 352, and the drain electrode 354 are positioned on the semiconductor layer 310. Alternatively, the driving thin film transistor Td may have an inverted staggered structure in which a gate electrode is located below the semiconductor layer and a source electrode and a drain electrode are located above the semiconductor layer. In this case, the semiconductor layer may be made of amorphous silicon.

Further, a switching thin film transistor (not shown), which is a switching element having substantially the same structure as the driving thin film transistor Td, is further formed on the substrate 302. [ The gate electrode 330 of the driving thin film transistor Td is connected to a drain electrode (not shown) of a switching thin film transistor (not shown) and the source electrode 352 of the driving thin film transistor Td is connected to a power supply wiring . A gate electrode (not shown) and a source electrode (not shown) of the switching thin film transistor (not shown) are connected to the gate wiring and the data wiring, respectively.

The organic light emitting diode display 300 may include a color filter (not shown) for absorbing light generated in the organic light emitting diode 400. For example, a color filter (not shown) can absorb red (R), green (G), blue (B), and white (W) light. In this case, color filter patterns of red, green, and blue that absorb light may be formed separately for each pixel region, and each of the color filter patterns may include an organic light emitting diode (OLED) 400 and the organic light emitting layer 430 in the organic light emitting layer 400. By adopting a color filter (not shown), the organic light emitting diode display 300 can realize full-color.

For example, when the organic light emitting diode display 300 is a bottom emission type, a color filter (not shown) for absorbing light may be disposed on the interlayer insulating layer 340 corresponding to the organic light emitting diode 400 . In an alternative embodiment, if the organic light emitting diode display 300 is a top emission type, the color filter may be located on top of the organic light emitting diode 400, i.e., above the second electrode 420.

A planarization layer 360 is formed on the entire surface of the substrate 302 over the source electrode 352 and the drain electrode 354. The planarization layer 360 has a flat upper surface and a drain contact hole 362 that exposes the drain electrode 354 of the driving thin film transistor Td. Here, the drain contact hole 362 is formed directly on the second semiconductor layer contact hole 344, but may be formed apart from the second semiconductor layer contact hole 344.

The light emitting diode 400 includes a first electrode 410 located on the planarization layer 360 and connected to the drain electrode 354 of the driving TFT Td, A light emitting layer 430 and a second electrode 420.

One electrode 410 is formed separately for each pixel region. The first electrode 410 may be an anode and may be formed of a conductive material having a relatively large work function value. For example, the first electrode 410 may be formed of a transparent conductive material such as ITO, IZO, ITZO, SnO, ZnO, ICO, and AZO.

Meanwhile, when the organic light emitting diode display device 300 of the present invention is a top emission type, a reflective electrode or a reflective layer may be further formed under the first electrode 310. For example, the reflective electrode or the reflective layer may be formed of an aluminum-palladium-copper (APC) alloy.

A bank layer 370 covering the edge of the first electrode 410 is formed on the planarization layer 360. The bank layer 370 exposes the center of the first electrode 410 corresponding to the pixel region.

An organic light emitting layer 430 is formed on the first electrode 410. In one exemplary embodiment, the organic light emitting layer 430 may have a single layer structure of a light emitting material layer. Alternatively, as shown in FIGS. 3 to 4, the organic light emitting layer 430 may include a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting material layer, a hole blocking layer, an electron transporting layer, and / Of the organic layer.

A second electrode 420 is formed on the substrate 302 on which the organic light emitting layer 430 is formed. The second electrode 420 is disposed on the front surface of the display region and is made of a conductive material having a relatively small work function value and can be used as a cathode. For example, the second electrode 420 may be formed of any one of an alloy or a combination thereof such as aluminum (Al), magnesium (Mg), calcium (Ca), silver (Ag), or aluminum- .

An encapsulation film 380 is formed on the second electrode 420 to prevent external moisture from penetrating into the organic light emitting diode 400. The encapsulation film 380 may have a laminated structure of a first inorganic insulating layer 382, an organic insulating layer 384, and a second inorganic insulating layer 386, but is not limited thereto.

As described above, since the organic light emitting diode 400 has a dopant having a delayed fluorescence characteristic in the organic light emitting layer 430, the light emitting efficiency is improved. Further, the organic light emitting layer 430 includes an organic compound represented by Chemical Formulas 1 to 3 as a host.

The organic compounds represented by the general formulas (1) to (3) are amphoteric compounds having a wide energy band gap and a high triplet energy level. When the organic compound represented by any one of Chemical Formulas 1 to 3 is used as a host of the light emitting layer 430, the host exciton interacts with the polaron so that the host excitons are all transferred to the dopant without luminescence disappearing. The luminous efficiency is improved while the dopant exciton generation efficiency is increased and the lifetime of the light emitting device can be increased while the damage to the light emitting material by the electro-oxidation and photo-oxidation due to non-emission disappearance is reduced. In addition, since a cyano group substituent can be optionally provided, light emission with high color purity can be realized.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to the technical ideas described in the following examples.

Synthesis Example 1: Synthesis of Compound 1

5 mL of a 5 mol% Pd (PPh ₃ ) solution was added to 5.4 g (12.0 mmol) of Compound 1-1, 3.9 g (12.0 mmol) of Compound 1-2, 12 mL (24.0 mmol) of 2M K ₂ CO ₃ aqueous solution, 50 mL of tetrahydrofuran, ₄ (Tetrakis (triphenylphosphine) palladium (0)) (0.58 g, 0.5 mmol) was added and the mixture was refluxed for 8 hours under nitrogen atmosphere and stirred. After completion of the reaction, the reaction mixture was cooled to room temperature, 50 mL of distilled water was added, and the mixture was extracted with chloroform (CHCl ₃ ). Dried over anhydrous magnesium sulfate, filtered and concentrated. Then, it was purified by column chromatography (hexane: methylene chloride = 4: 1). After drying, Compound 1 (4.53 g, yield 58%) was obtained. As a result of measurement of the mass spectrum of the obtained solid, a peak was confirmed at M / Z = 650.

Synthesis Example 2: Synthesis of Compound 2

Compound 2-1 2.87 g (10.0 mmol), compound 2-2 3.87 g (12.0 mmol), 2M K 2 CO 3 aqueous solution 10 mL (20.0 mmol), in tetrahydrofuran 50 mL, 5 mol% Pd ( PPh 3) 4 (0.5 mmol) were added, and the mixture was refluxed for 8 hours under a nitrogen atmosphere and stirred. After completion of the reaction, the reaction mixture was cooled to room temperature, 50 mL of distilled water was added, and the mixture was extracted with chloroform (CHCl ₃ ). Dried over anhydrous magnesium sulfate, filtered and concentrated. Then, it was purified by column chromatography (hexane: ethyl acetate = 1: 1). After drying, Compound 2 (3.10 g, yield 64%) was obtained. As a result of measurement of the mass spectrum of the obtained solid, a peak was confirmed at M / Z = 485.

Synthesis Example 3: Synthesis of Compound 3

5 mL of a 5 mol% Pd (PPh ₃ ) ₄ (12.0 mmol) of Compound 1-1, 2.9 g (12.0 mmol) of Compound 2-2, 12 mL (24.0 mmol) of 2M K ₂ CO ₃ aqueous solution, 50 mL of tetrahydrofuran, 0.58 g (0.5 mmol) were added thereto, and the mixture was refluxed for 8 hours under nitrogen atmosphere and stirred. After completion of the reaction, the reaction mixture was cooled to room temperature, 50 mL of distilled water was added, and the mixture was extracted with chloroform (CHCl ₃ ). Dried over anhydrous magnesium sulfate, filtered and concentrated. Then, it was purified by column chromatography (hexane: methylene chloride = 4: 1). After drying, Compound 3 (4.68 g, yield 60%) was obtained. As a result of measurement of the mass spectrum of the obtained solid, a peak was confirmed at M / Z = 650.

Synthesis Example 4: Synthesis of Compound 4

5 mL of 5 mol% Pd (PPh ₃ ) ₄ (20.0 mmol) of Compound 2-1, 7.74 g (24.0 mmol) of Compound 1-2, 20 mL (40.0 mmol) of 2M K ₂ CO ₃ aqueous solution, 100 mL of tetrahydrofuran, 1.6 g (1.0 mmol) were added thereto, and the mixture was refluxed for 8 hours under nitrogen atmosphere and stirred. After completion of the reaction, the reaction mixture was cooled to room temperature, 100 mL of distilled water was added, and the mixture was extracted with chloroform (CHCl ₃ ). Dried over anhydrous magnesium sulfate, filtered and concentrated. Then, it was purified by column chromatography (hexane: ethyl acetate = 1: 1). After drying, Compound I (6.40 g, yield 66%) was obtained. As a result of measurement of the mass spectrum of the obtained solid, a peak was confirmed at M / Z = 485.

Synthesis Example 5: Synthesis of Compound 5

1) Synthesis of intermediate 5-2

A mixture of 4.2 g (20.0 mmol) of the compound 5-1, 6.5 g (21.0 mmol) of 3-bromo-5-iodobenzonitrile and 8.3 g (60.0 mmol) of potassium carbonate in a mixed solvent of 100 mL of tetrahydrofuran and 30 mL of distilled water dissolved in, followed by the addition of _{Pd (PPh 3) 4 0.6 g} (0.5 mmol) was refluxed for 12 hours. After cooling to room temperature, the water layer was removed, and magnesium sulfate was added to the organic layer, followed by filtration. Concentrated, and then purified by column chromatography to obtain Intermediate 5-2 (2.5 g, yield 36.4%).

2) Synthesis of Compound 5

Compound 5-2 2.53 g (7.3 mmol), compound 2-1 2.30 g (8.0 mmol), 2M K 2 CO 3 aqueous solution 10 mL (20.0 mmol), in tetrahydrofuran 50 mL, 5 mol% Pd ( PPh 3) 4 0.58 g (0.5 mmol) were added thereto, and the mixture was refluxed for 8 hours under nitrogen atmosphere and stirred. After completion of the reaction, the reaction mixture was cooled to room temperature, 50 mL of distilled water was added, and the mixture was extracted with chloroform (CHCl ₃ ). Dried over anhydrous magnesium sulfate, filtered and concentrated. Then, it was purified by column chromatography (hexane: ethyl acetate = 1: 2). After drying, Compound 5 (1.86 g, yield 50%) was obtained. As a result of measurement of the mass spectrum of the obtained solid, a peak was confirmed at M / Z = 510.

Synthesis Example 6: Synthesis of Compound 6

1) Synthesis of intermediate 6-2

6.5 g (21.0 mmol) of 3-bromo-5-iodobenzonitrile and 8.3 g (60.0 mmol) of potassium carbonate were dissolved in a mixed solvent of 100 mL of tetrahydrofuran and 30 mL of distilled water dissolved in, followed by the addition of _{Pd (PPh 3) 4 0.6 g} (0.5 mmol) was refluxed for 12 hours. After cooling to room temperature, the water layer was removed, and magnesium sulfate was added to the organic layer, followed by filtration. Concentrated, and then purified by column chromatography to obtain Compound 6-2 (2.4 g, yield 34.6%).

2) Synthesis of Compound 6

Compound 6-2 2.53 g (7.3 mmol), compound 2-1 2.30 g (8.0 mmol), 2M K 2 CO 3 aqueous solution 10 mL (20.0 mmol), in tetrahydrofuran 50 mL, 5 mol% Pd ( PPh 3) 4 0.58 g (0.5 mmol) were added thereto, and the mixture was refluxed for 8 hours under a nitrogen atmosphere and stirred. After completion of the reaction, the reaction mixture was cooled to room temperature, 50 mL of distilled water was added, and the mixture was extracted with chloroform (CHCl ₃ ). Dried over anhydrous magnesium sulfate, filtered and concentrated. Then, it was purified by column chromatography (hexane: methylene chloride = 2: 1). After drying, Compound 6 (1.79 g, yield 48%) was obtained. As a result of measurement of the mass spectrum of the obtained solid, a peak was confirmed at M / Z = 510.

Synthesis Example 7: Synthesis of Compound 9

1) Synthesis of 9-1 in the middle

A mixture of 6.5 g (20 mmol) of compound 1-2, 6.6 g (26.0 mmol) of bis (pinacolate) diboron and 1.1 g (1.5 mmol) of [1,1-bis (diphenylphosphino) ferrocene] dichloropalladium mmol) and toluene (40 mL) were added, and the mixture was stirred under reflux. After completion of the reaction, the reaction mixture was filtered through silica gel / celite, concentrated under reduced pressure and separated into a column. The resulting liquid was concentrated under reduced pressure, then, crystallized with hexane and filtered to obtain Compound 9-1 (5.8 g, yield 78% Respectively.

2) Synthesis of Compound 9

The compound 9-1 was dissolved in a mixed solvent of 4.4 g (12.0 mmol) of Compound 9-2, 5.9 g (12.0 mmol) of Compound 9-2 and 5.0 g (36 mmol) of potassium carbonate in 100 mL of tetrahydrofuran and 300 mL of distilled water. ₃₎ followed by the addition of ₄ 1.4 g (1.2 mmol) was refluxed for 12 hours. After cooling to room temperature, the water layer was removed, and magnesium sulfate was added to the organic layer, followed by filtration. Concentrated and purified by column chromatography to obtain Compound 9 (5.5 g, yield 70.4%). As a result of measurement of the mass spectrum of the obtained solid, a peak was confirmed at M / Z = 650.

Synthesis Example 8: Synthesis of Compound 15

1) Synthesis of intermediate 15-1

1.1 g (1.5 mmol) of Compound 6-2, 7.0 g (20 mmol) of bis (pinacolate) diboron and 6.6 g (26.0 mmol) of [1,1-bis (diphenylphosphino) ferrocene] dichloropalladium mmol) and toluene (40 mL) were added, and the mixture was stirred under reflux. After completion of the reaction, the reaction mixture was filtered through silica gel / celite, and concentrated under reduced pressure. The separated product was concentrated under reduced pressure. The resulting residue was crystallized from hexane and filtered to obtain Compound 15-1 (5.8 g, yield 74% Respectively.

2) Synthesis of compound 15

The compound 15-1 was dissolved in a mixed solvent of 4.7 g (12.0 mmol) of Compound 9-2, 5.9 g (12.0 mmol) of Compound 9-2 and 5.0 g (6 mmol) of potassium carbonate in 100 mL of tetrahydrofuran and 300 mL of distilled water. ₃₎ followed by the addition of ₄ 1.4 g (1.2 mmol) was refluxed for 12 hours. After cooling to room temperature, the water layer was removed, and magnesium sulfate was added to the organic layer, followed by filtration. Concentrated, and then purified by column chromatography to obtain Compound 15 (5.3 g, yield 65.2%). As a result of measurement of the mass spectrum of the obtained solid, a peak was confirmed at M / Z = 675.

Experimental Example 1: Evaluation of physical properties of organic compounds

The physical properties of the compounds 1 to 4 synthesized in Synthesis Examples 1 to 4 were simulated. HOMO energy level, LUMO energy level, glass transition temperature (T _g ), melting point (T _m ), decomposition temperature (Td), HOMO energy level for each organic compound, (E _g ), the triplet energy level (T ₁ ), and the difference between the triplet energy level and the singlet energy level (ΔE _ST ) between the LUMO and the LUMO were evaluated. The evaluation results are shown in Table 1 below. The physical properties of the organic compounds used in Comparative Example 1 to be described later were evaluated together with Comparative Examples (Ref.).

Properties of organic compounds compound HOMO
(eV) LUMO
(eV) T _g
(° C) T _m
(° C) T _d-1 %
(° C) E _g
(eV) T ₁
(eV) ΔE _ST
(eV) Comparative Example 1 -5.82 -2.92 126 280 362 2.90 2.75 0.15 Compound 1 -5.78 -2.07 124 243 385 3.71 2.84 0.87 Compound 2 -5.98 -2.52 121 320 347 3.46 2.85 0.61 Compound 3 -5.84 -2.36 129 ND 351 3.48 2.92 0.56 Compound 4 -5.97 -2.49 80 ND 341 3.48 2.91 0.57 HOMO: Film (100 nm / ITO), by AC3, LUMO: produced at film adsorption edge;
T1 gap: value calculated by Gaussian ED-DFT (time-dependent density functional theory).
Eg: LUMO - HOMO; T _g , T _m : measured with TA Q100; T _d : measured with TA Q500

As shown in Table 1, the HOMO energy level, the LUMO energy level, and the energy band gap of the compounds 1 to 4 were suitable for use in the light emitting material layer, and in consideration of the triplet energy level, Is suitable for energy transfer for forming an exciton. In particular, since the difference between the singlet energy level and the triplet energy level is relatively large, the excitons generated in the light emission process are not directly interacted with the surrounding polaron, but are directly transferred to the dopant. Thus, it was confirmed that good emission efficiency was obtained while reducing non-emission disappearance. Also, it was confirmed that the glass transition temperature, melting point and the like were high, and the heat resistance was also excellent.

Example 1: Fabrication of organic light emitting diode using Compound 1

An organic light emitting diode was prepared by applying Compound 1 as a host of a light emitting material layer. First, the glass substrate with 40 mm x 40 mm x 0.5 mm thick ITO (with reflector) electrodes was ultrasonically cleaned with isopropyl alcohol, acetone, DI water for 5 minutes, and then dried in an oven at 100 ° C. After the substrate was cleaned, it was subjected to an O ₂ plasma treatment in a vacuum for 2 minutes and transferred to a deposition chamber for deposition of other layers on the top. An organic layer was deposited by evaporation from a heated boat under a vacuum of about 10 ^-7 Torr in the following order. At this time, the deposition rate of the organic material was set to 1 Å / s.

A hole injection layer (HIL; HAT-CN, 70 ANGSTROM), a hole transport layer (HTL; NPB, 780 ANGSTROM), an electron blocking layer (EBL; mCBP, 150 ANGSTROM) 4CzIPN was doped with 30% by weight of a retardation fluorescent material, 350 Å), a hole blocking layer (HBL; B3PYMPM; 100 Å), an electron transport layer (ETL: TPBi, 250 Å), an electron injection layer (EIL; LiF, 8 Å) Cathode (Al; 1000 A).

A capping layer (CPL) was formed and encapsulated with glass. After deposition of these layers, the film was transferred from the deposition chamber into a dry box for subsequent film formation and subsequently encapsulated using a UV cured epoxy and a getter.

Examples 2 to 4: Fabrication of organic light emitting diodes

Compound 2 (Example 2) synthesized in Synthesis Example 2, Compound 3 (Example 3) synthesized in Synthesis Example 3, Compound 4 (Synthesis Example 4) synthesized in Synthesis Example 4 (Example 4) ) Was used as the organic light emitting diode, and the procedure of Example 1 was repeated to produce an organic light emitting diode.

Comparative Examples 1 and 2: Fabrication of organic light emitting diode

(9H-carbazol-9-yl) -1,1'-biphenyl (CBP) was used in place of Compound 1 as the host of the light emitting material layer And the procedure of Example 1 was repeated to produce an organic light emitting diode.

Experimental Example: Measurement of luminescence characteristics of organic light emitting diode

The properties of the organic light emitting diodes fabricated in Examples 1 to 4 and Comparative Examples 1 and 2 were measured. Each organic light emitting diode having an emission area of 9 mm < 2 > was connected to an external power source, and device characteristics were evaluated at room temperature using a current source (KEITHLEY) and a photometer (PR 650). (Cd / A), power efficiency (lm / W), external quantum efficiency (EQE), CIE chromaticity coordinates, and 3000 (nm) of the organic light emitting diodes at a current density of 10 mA / The time from the nit to the time when the brightness was reduced to 95% (T ₉₅ ) was measured. The measurement results are shown in Table 2 below.

Properties of Organic Light Emitting Diodes device V cd / A lm / W EQE (%) CIE (x) CIE (y) T ₉₅ Comparative Example 1 3.8 23.7 19.4 8.3 0.34 0.58 10 Comparative Example 2 4.8 44.0 28.7 15.0 0.33 0.59 32 Example 1 4.3 46.4 33.6 15.7 0.33 0.59 235 Example 2 4.5 47.4 33.1 16.0 0.33 0.59 200 Example 3 4.2 47.8 35.5 16.2 0.34 0.59 198 Example 4 4.4 52.7 37.1 17.7 0.34 0.59 220

As shown in Table 2, when the organic compound synthesized according to the present invention is used as a host of the light emitting material layer, as compared with the case where the material of Comparative Example 1 having ΔE _ST of 0.1 eV is used as the host of the light emitting material layer, Efficiency, power efficiency, external quantum efficiency, and device lifetime (T ₉₅ ) increased by up to 122.4%, 91.2%, 113.3% and 22 times, respectively. In addition, when the organic compound synthesized according to the present invention was used as the host of the light emitting material layer, the driving voltage was lowered by 12.5% at the maximum compared to the case where CBP of Comparative Example 2 was used as the host of the light emitting material layer. Power efficiency and external quantum efficiency increased by up to 19.8%, 29.3%, 18.0% and 7.34 times, respectively. As a result, it has been confirmed that the organic compound of the present invention is applied to the organic light emitting layer to lower the driving voltage of the light emitting diode, improve the light emitting efficiency, and improve the device lifetime. Accordingly, the organic light emitting diode according to the present invention can be utilized for an organic light emitting diode display device and / or a light emitting device such as an illumination device, which has low power consumption and improved luminous efficiency and device life.

Although the present invention has been described based on the exemplary embodiments and examples of the present invention, the scope of the present invention is not limited to the technical ideas described in the embodiments and examples. It will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the present invention. It is evident, however, that the appended claims are intended to cover all such modifications and changes as fall within the scope of the invention.

100, 200, 400: organic light emitting diode
110, 210, 410: first electrode 120, 220, 420: second electrode
130, 230, 430: an organic light emitting layer 140, 240: a hole injection layer
150, 250: Hole transport layer 160, 260: Light emitting material layer
170, 270: electron transport layer 180, 280: electron injection layer
255: electron blocking layer 265: hole blocking layer
300: organic light emitting diode display Td: driving thin film transistor

Claims (13)

An organic compound represented by the following formula (1).
Formula 1

Wherein R ₁ to R ₂₃ are each independently selected from the group consisting of hydrogen, deuterium, tritium, silyl groups, C ₁ to C ₂₀ alkyl groups, C ₁ to C ₂₀ alkoxy groups, C ₁ to C ₂₀ alkylamine groups, C ₅ ~ C ₃₀ Homo aryl group, C ₄ ~ C ₃₀ heteroaryl group, C ₅ ~ C ₃₀ Homo alkylaryl group, C ₄ ~ C ₃₀ heteroaryl-alkyl aryl group, C ₅ ~ C ₃₀ Homo aryloxy group, C ₄ ~ C ₃₀ heteroaryloxy group, C ₅ ~ C ₃₀ Homo arylamine group, a C ₄ ~ C ₃₀ heteroaryl amine group, or adjacent groups unsubstituted or combined substituted each other C ₅ ~ C _30-homo-aryl group or a C ₄ ~ C ₃₀ heteroaryl group (O) or sulfur (S), L ₁ and L ₂ each independently represent a C ₅ -C ₃₀ homoarylene group which is unsubstituted or substituted with a cyano group, a substituted A C ₄ -C ₃₀ heteroarylene group which is unsubstituted or substituted by cyano group, a C ₅ -C ₃₀ homoalkylarylene group which is unsubstituted or substituted by cyano group, a C ₄ -C ₃₀ aryl group which is unsubstituted or substituted by cyano group ₃₀ heteroalkyl arylene group, is optionally substituted with a cyano group-substituted C ₅ ~ C ₃₀ Homo aryloxy xylene group, an unsubstituted or substituted by a cyano group, C ₄ ~ C ₃₀ heteroaryloxy xylene group, an unsubstituted or substituted by a cyano group A C ₅ to C ₃₀ homoarylene amine group and a C ₄ to C ₃₀ heteroarylene amine group unsubstituted or substituted with a cyano group; a, b, and c are each independently 0 or 1; )
The method according to claim 1,
Wherein the organic compound represented by the formula (1) is a compound represented by the following formula (2a) or (2b).
Formula 2a

2b

(Wherein, X, a, b and c are each as defined in formula (1), R ₃₁ to R ₃₈ are each independently hydrogen, deuterium, tritium, Wherein the aromatic ring is selected from the group consisting of a phenyl group, a biphenyl group, a pyrrolyl group, a triazinyl group, an imidazolyl group, a pyrazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, R ₄₁ and R ₄₂ are each independently selected from the group consisting of hydrogen, deuterium, tritium, or cyano group), a benzyl group,
The method according to claim 1,
Wherein the organic compound represented by the formula (1) is any compound represented by the following formula (3).
(3)

A first electrode and a second electrode facing each other; And
And an organic light emitting layer disposed between the first electrode and the second electrode,
Wherein the organic light emitting layer comprises an organic compound represented by Formula 1 below.
Formula 1

Wherein R ₁ to R ₂₃ are each independently selected from the group consisting of hydrogen, deuterium, tritium, silyl groups, C ₁ to C ₂₀ alkyl groups, C ₁ to C ₂₀ alkoxy groups, C ₁ to C ₂₀ alkylamine groups, C ₅ ~ C ₃₀ Homo aryl group, C ₄ ~ C ₃₀ heteroaryl group, C ₅ ~ C ₃₀ Homo alkylaryl group, C ₄ ~ C ₃₀ heteroaryl-alkyl aryl group, C ₅ ~ C ₃₀ Homo aryloxy group, C ₄ ~ C ₃₀ heteroaryloxy group, C ₅ ~ C ₃₀ Homo arylamine group, a C ₄ ~ C ₃₀ heteroaryl amine group, or adjacent groups unsubstituted or combined substituted each other C ₅ ~ C _30-homo-aryl group or a C ₄ ~ C ₃₀ heteroaryl group (O) or sulfur (S), L ₁ and L ₂ each independently represent a C ₅ -C ₃₀ homoarylene group which is unsubstituted or substituted with a cyano group, a substituted A C ₄ -C ₃₀ heteroarylene group which is unsubstituted or substituted by cyano group, a C ₅ -C ₃₀ homoalkylarylene group which is unsubstituted or substituted by cyano group, a C ₄ -C ₃₀ aryl group which is unsubstituted or substituted by cyano group ₃₀ heteroalkyl arylene group, is optionally substituted with a cyano group-substituted C ₅ ~ C ₃₀ Homo aryloxy xylene group, an unsubstituted or substituted by a cyano group, C ₄ ~ C ₃₀ heteroaryloxy xylene group, an unsubstituted or substituted by a cyano group A C ₅ to C ₃₀ homoarylene amine group and a C ₄ to C ₃₀ heteroarylene amine group unsubstituted or substituted with a cyano group; a, b, and c are each independently 0 or 1; )
5. The method of claim 4,
Wherein the organic compound is a compound represented by the following formula (2a) or (2b).
Formula 2a

2b

(Wherein, X, a, b and c are each as defined in formula (1), R ₃₁ to R ₃₈ are each independently hydrogen, deuterium, tritium, Wherein the aromatic ring is selected from the group consisting of a phenyl group, a biphenyl group, a pyrrolyl group, a triazinyl group, an imidazolyl group, a pyrazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, R ₄₁ and R ₄₂ are each independently selected from the group consisting of hydrogen, deuterium, tritium, or cyano group), a benzyl group,
5. The method of claim 4,
Wherein the organic compound represented by Formula 1 is any compound represented by Formula 3 below.
(3)

5. The method of claim 4,
Wherein the organic compound is used as a host of the light emitting material layer.
8. The method of claim 7,
Wherein the light emitting material layer further comprises a dopant.
9. The method of claim 8,
(HOMO ^H -HOMO ^D |) between the highest level occupied molecular orbital energy level (HOMO ^H ) of the host and the highest level occupied molecular orbital energy level (HOMO ^D ) of the dopant or the lowest level non occupied molecular orbital The difference (LUMO ^H -LUMO ^D |) between the energy level (LUMO ^H ) and the lowest level non occupied molecular orbital energy level (LUMO ^D ) of the dopant is 0.5 eV or less.
9. The method of claim 8,
Excited state singlet energy level (S ₁ ^D) and the organic light emitting diode difference (ΔE _ST ^D) is 0.3 eV or less of the excited state triplet energy level (T ₁ ^D) of the dopant.
11. The method of claim 10,
Wherein the difference (? E _ST ^H ) between the excited single-state energy level (S ₁ ^H ) and the excited triplet energy level (T ₁ ^H ) of the organic compound exceeds 0.3 eV.
Board;
12. The organic light emitting diode according to any one of claims 4 to 11, which is disposed on the substrate. And
And a driving unit connected to the first electrode of the organic light emitting diode,
And an organic light emitting device.
13. The method of claim 12,
Wherein the organic light emitting device includes an organic light emitting diode display.

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