TW201341378A - Novel compound, material for organic electroluminescent element and organic electroluminescent element - Google Patents

Abstract

Provided is a compound represented by formula (A). In formula (A), Y1 to Y5 are each independently a CR1, a nitrogen atom, or a carbon atom linked to a Cz, wherein at least one of Y1 to Y5 is a nitrogen atom, and m is an integer of 1 to 3. Y11 to Y14 are each independently a CR2, a nitrogen atom, or a carbon atom linked to an A, and Y15 to Y18 are each independently a CR2 or a nitrogen atom. Y21 to Y24 are each independently a CR3, a nitrogen atom, or a carbon atom linked to an A, and Y25 to Y28 are each independently a CR3 or a nitrogen atom. R1 to R3 are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, etc. Cz is a nitrogen-containing polycyclic group represented by any one of formulas (1) to (5). (A) (1) (2) (3) (4) (5)

Description

Novel compound, material for organic electroluminescent device, and organic electroluminescent device

The present invention relates to a novel compound, a material for an organic electroluminescent device comprising the same, and an organic electroluminescent device.

Among the organic electroluminescence (EL) elements, there are fluorescent and phosphorescent types, and the optimum component design has been studied in accordance with the respective light-emitting mechanisms. It is known that a phosphorescent organic EL element cannot be obtained as a high-performance element by the simple conversion of the fluorescent element technology according to its light-emitting characteristics. It can be considered that the reason is usually as follows.

First, the phosphorescent system utilizes the luminescence of triplet excitons, so the energy gap of the compound used in the luminescent layer must be large. The reason is that the value of the energy gap (hereinafter, also referred to as singlet energy) of a certain compound is usually larger than the triplet energy of the compound (in the present invention, the energy difference between the lowest excited triplet state and the substrate state). value.

Therefore, in order to efficiently encapsulate the triplet energy of the phosphorescent dopant material into the light-emitting layer, first, a host material having a triplet energy greater than the triplet energy of the phosphorescent dopant material must be used in the light-emitting layer. . Further, an electron transport layer adjacent to the light-emitting layer and a hole transport layer are provided, and a compound having a triplet energy greater than a triplet energy of the phosphorescent dopant material must be used in the electron transport layer and the hole transport layer.

Thus, in the case of the element design concept of the conventional organic EL element, a compound having a larger energy gap than the compound used in the fluorescent type organic EL element is used for the phosphorescent organic EL element. The driving voltage of the entire organic EL element is increased.

Moreover, a hydrocarbon system having high oxidation resistance or high reduction resistance which is useful in a fluorescent element Since the compound has a wide diffusion of π electron clouds, the energy gap is small. Therefore, in the phosphorescent organic EL device, it is difficult to select such a hydrocarbon-based compound, and an organic compound containing a hetero atom such as oxygen or nitrogen is selected, and as a result, the phosphorescent organic EL device has a fluorescent organic EL device. Compared to the problem of shorter life.

Further, the exciton relaxation rate of the triplet excitons of the phosphorescent dopant material is very long compared to the singlet excitons, and this also has a large influence on the device performance. That is, since the light emission from the singlet exciton is faster because of the relaxation speed associated with the light emission, it is less likely to cause the diffusion of excitons to the peripheral layer of the light-emitting layer (for example, the hole transport layer or the electron transport layer), and high-efficiency light is expected. . On the other hand, since the light emission from the triplet excitons is spin-inhibited and the relaxation speed is slow, it is easy to cause the exciton to diffuse to the peripheral layer, and the thermal energy is deactivated by the specific phosphorescent compound. That is, the control of the recombination region of the electrons and the holes is more important than the fluorescent organic EL device.

In view of the above, in the high performance of the phosphorescent organic EL device, it is necessary to select a material different from the fluorescent organic EL device and the device design.

In particular, in the case of a phosphorescent organic EL device which emits blue light, it is necessary to use a compound having a larger triplet energy in the light-emitting layer or its peripheral layer than the green-red-emitting phosphorescent organic EL device. Specifically, in order to obtain blue phosphorescence with no loss of efficiency, the triplet energy of the host material used in the light-emitting layer must be approximately 3.0 eV or more.

In such a case, Patent Documents 1 and 2 disclose materials of an organic EL device in which a carbazole skeleton and a well ring are combined.

Patent Document 1: International Publication No. 2003-078541

Patent Document 2: International Publication No. 2011-019156

In order to obtain a higher triplet energy, and to satisfy as an organic EL material The compounds of other properties required do not simply combine the molecular moieties with higher triplet energy such as heterocyclic compounds, but use molecular ideas that take into account the electronic states of π electrons.

An object of the present invention is to provide a novel compound which can improve the luminous efficiency of an organic electroluminescence device, a material for an organic electroluminescence device containing the compound, and an organic electroluminescence device using the material for the organic electroluminescence device. .

According to the present invention, the following compounds and the like are provided.

A compound represented by the following formula (A):

In (in Formula _{(A), Y 1 ~ Y} 5 each independently represent a carbon CR _1, a nitrogen atom, or Cz bonding of atoms, Y ₁ ~ Y ₅ in the at least one nitrogen atom; in R ₁ is present In the case of plural cases, a plurality of R _{1 's} may be the same or different from each other; m is an integer of 1 to 3, and when m is 2 or more, a plurality of Cz may be the same or different from each other; Y ₁₁ to Y ₁₄ respectively independently carbon atom CR _2, a nitrogen atom, or A key knot, Y ₁₅ ~ Y ₁₈ each independently CR ₂ or a nitrogen atom; to when R ₂ is present case plural, the plural R ₂ s each may be the same Y ₂₁ ~Y ₂₄ are independently CR ₃ , a nitrogen atom, or a carbon atom bonded to A, and Y ₂₅ ~Y ₂₈ are independently CR ₃ or a nitrogen atom; respectively, there are a plurality of R ₃ In the case, a plurality of R _{3 's} may be the same or different from each other; R ₁ to R ₃ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, substituted or unsubstituted. a cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, substituted Or unsubstituted ring carbon 6 to 18 aromatic hydrocarbon ring groups, substituted or unsubstituted aryloxy groups having 6 to 18 ring carbon atoms, substituted or unsubstituted aromatic heterocyclic groups having 5 to 18 ring atoms; a substituted or unsubstituted amino group, a substituted or unsubstituted fluorenyl group, a fluoro group, or a cyano group; and Ar is a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 carbon atoms; Or a substituted or unsubstituted aromatic heterocyclic group having 5 to 18 ring atoms; A is a single bond, a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, substituted or unsubstituted An aromatic hydrocarbon ring group having 6 to 18 carbon atoms or a substituted or unsubstituted aromatic heterocyclic group having 5 to 18 ring atoms; wherein, when A is a single bond, Y ₁₁ Any one of Y Y ₁₄ is directly bonded to any one of Y ₂₁ to Y ₂₄ ; and Cz is a nitrogen-containing polycyclic group represented by any one of the following formulas (1) to (5);

(In the formulae (1) to (5), X ₁ to X ₈ are each independently CR _a or a nitrogen atom, and Z is a single bond, an oxygen atom, a sulfur atom, -S(=O)-, -S (= O) ₂ -, -Si(R _c R _d )-, -C(R _e R _f )-, or -N(R _g )-, R _a ~R _g are each independently the same group as R ₁ , when the presence of a plurality of in case of R _a, plural R _a may be identical or different from each other; the position shown in Cz * nitrogen-containing Y ₁ ~ Y ₅ of the six-membered rings bonded)).

2. The compound according to 1, wherein at least one of Y ₂ and Y ₄ is a nitrogen atom.

3. The compound according to 1, wherein at least one of Y ₁ and Y ₅ is a nitrogen atom.

4. The compound according to any one of 1 to 3, wherein any one of Y ₁ to Y ₅ is a nitrogen atom.

5. The compound according to any one of 1 to 4, wherein Z is a single bond.

6. The compound according to any one of 1 to 5, wherein Cz is a nitrogen-containing polycyclic group represented by the above formula (1).

7. The compound according to any one of 1 to 5, wherein Cz is a nitrogen-containing polycyclic group represented by the above formula (4).

8. The compound according to any one of 1 to 7, wherein A is a single bond.

The compound according to any one of 1 to 8, wherein Y ₂ or Y ₄ is a carbon atom bonded to Cz.

A material for an organic electroluminescent device, which comprises the compound according to any one of 1 to 9.

An organic electroluminescence device comprising an organic thin film layer containing one or more layers of a light-emitting layer between a cathode and an anode, and at least one of the organic thin film layers containing a material for an organic electroluminescence element such as 10.

12. The organic electroluminescence device according to 11, wherein the light-emitting layer contains the material for the organic electroluminescence device.

13. The organic electroluminescent device according to 11 or 12, wherein the luminescent layer comprises a phosphorescent material.

14. The organic electroluminescent device according to 13, wherein the phosphorescent material is an orthometalated complex of a metal atom selected from the group consisting of iridium (Ir), osmium (Os), and platinum (Pt).

The organic electroluminescent device according to any one of the items 11 to 14, wherein the organic thin film layer is provided between the cathode and the light-emitting layer, and the organic thin film layer contains the material for the organic electroluminescent device.

16. The organic electroluminescent device of 15, wherein the organic thin film layer is an electron transport layer.

The organic electroluminescence device according to any one of the items 11 to 16, wherein the organic thin film layer is provided between the anode and the light-emitting layer, and the organic thin film layer contains the material for the organic electroluminescence element.

According to the present invention, there is provided a novel compound which can improve the luminous efficiency of an organic electroluminescence device, a material for an organic electroluminescence device containing the compound, and an organic electroluminescence device using the material for the organic electroluminescence device. .

1, 2‧‧‧Organic EL components

10‧‧‧Substrate

20‧‧‧Anode

30‧‧‧ hole transmission area

40‧‧‧phosphorescence layer

42‧‧‧ spacer

44‧‧‧Fluorescent layer

50‧‧‧Electronic transmission area

60‧‧‧ cathode

Fig. 1 is a view showing an embodiment of an organic EL device of the present invention.

Fig. 2 is a view showing another embodiment of the organic EL device of the present invention.

Fig. 3 is a view showing an electron cloud distribution of HOMO and LUMO of Compound A synthesized in Synthesis Example 1.

Fig. 4 is a view showing an electron cloud distribution of HOMO and LUMO of Compound B synthesized in Synthesis Example 2.

Fig. 5 is a view showing an electron cloud distribution of HOMO and LUMO of the compound H-1.

The compound of the present invention is represented by the following formula (A).

In the formula (A), Y ₁ to Y ₅ each independently represent a CR ₁ , a nitrogen atom, or a carbon atom bonded to Cz, and at least one of Y ₁ to Y ₅ is a nitrogen atom. When R in the presence of a plurality of case _1, a plurality of R ₁ may be identical or different from each other. m is an integer of 1 to 3. When m is 2 or more, a plurality of Cz may be the same or different from each other.

Preferably, at least one of Y ₂ and Y ₄ is a nitrogen atom. Further, it is also preferred that at least one of Y ₁ and Y ₅ is a nitrogen atom.

Further, it is preferred that only one of Y ₁ to Y ₅ is a nitrogen atom, and the nitrogen-containing six-membered ring containing Y ₁ to Y ₅ is a pyridine ring.

Y ₁₁ to Y ₁₄ are each independently a CR ₂ , a nitrogen atom, or a carbon atom bonded to A, and Y ₁₅ to Y ₁₈ are each independently a CR ₂ or a nitrogen atom. When R in the presence of a plurality of case _2, a plurality of R ₂ may be identical or different from each other.

Y ₂₁ to Y ₂₄ are each independently a CR ₃ , a nitrogen atom, or a carbon atom bonded to A, and Y ₂₅ to Y ₂₈ are each independently a CR ₃ or a nitrogen atom. When R in the presence of a plurality of case _3, plural R ₃ may be identical or different from each other.

R ₁ to R ₃ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, substituted or Unsubstituted alkoxy group having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyloxy group having 3 to 20 ring carbon atoms, substituted or unsubstituted aromatic ring having 6 to 18 carbon atoms a hydrocarbon group, a substituted or unsubstituted aryloxy group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 5 to 18 ring atoms, substituted or unsubstituted Substituted amine, substituted or unsubstituted fluorenyl, fluoro, or cyano.

Ar is a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 carbon atoms or a substituted or unsubstituted aromatic heterocyclic group having 5 to 18 ring atoms.

A is a single bond, a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 carbon atoms, or a substituted or unsubstituted The aromatic heterocyclic group having a ring number of 5 to 18 atoms.

A is preferably a single bond. Furthermore, in the case where A is a single bond, any of Y ₁₁ to Y ₁₄ is directly bonded to any of Y ₂₁ to Y ₂₄ .

Cz is a nitrogen-containing polycyclic group represented by any one of the following formulas (1) to (5), and preferably a nitrogen-containing polycyclic group represented by the following formula (1) or (4).

Cz is preferably bonded to Y ₂ or Y ₄ . The compound of the present invention has a higher T1 (triplet energy level) by bonding Cz to Y ₂ or Y ₄ .

In the formulae (1) to (5), X ₁ to X ₈ are each independently CR _a or a nitrogen atom.

Z is a single bond, an oxygen atom, a sulfur atom, -S(=O)-, -S(=O) ₂ -, -Si(R _c R _d )-, -C(R _e R _f )-, or - N(R _g )-, preferably a single bond.

R _a ~ R _g are each independently the same as R is of group _1, in the presence of a plurality of R _a case, a plurality of R _a may be identical or different from each other.

Cz is bonded to the nitrogen-containing six-membered ring containing Y ₁ to Y ₅ at the position indicated by *.

The compound of the present invention has a condensed nitrogen-containing heterocyclic ring such as two carbazole rings bonded to a nitrogen-containing six-membered ring containing Y ₁ to Y ₅ excellent in electron injectability, and thus has a higher triple weight suitable for blue phosphorescence. State energy. The substituent of the nitrogen-containing six-membered ring is not a nitrogen-containing polycyclic group represented by any one of the above formulas (1) to (5), that is, a condensed nitrogen-containing heterocyclic group, for example, a hydrocarbon aromatic ring such as a phenyl group. In order to diffuse the conjugated system to the hydrocarbon aromatic ring group, T1 becomes small, and the triplet energy encapsulation becomes insufficient.

The compound of the present invention has a condensed nitrogen-containing heterocyclic ring such as two carbazole rings bonded to a nitrogen-containing six-membered ring containing Y ₁ to Y ₅ , so that the π-conjugated system is cut by a nitrogen-containing six-membered ring, thereby preventing The π-conjugated system is excessively diffused and has a higher triplet energy.

Further, the compound of the present invention is bonded to a condensed nitrogen-containing heterocyclic ring which is one of nitrogen-containing six-membered rings containing Y ₁ to Y ₅ , and further condensed nitrogen-containing via an A bond or a direct bond (link) carbazole ring or the like. Heterocyclic. Therefore, the distribution of HOMO in two condensation nitrogen-containing heterocycles and HOMO (the highest occupied molecular orbital) on A is widely distributed. Further, LUMO (the lowest unoccupied molecular orbital domain) is localized on the nitrogen-containing six-membered ring containing Y ₁ to Y ₅ . Therefore, since HOMO is separated from LUMO, the balance of charge injection properties is excellent.

Therefore, by including the compound of the present invention in the light-emitting layer of the organic EL device, the charge balance in the light-emitting layer can be improved. When the degree of coincidence between HOMO and LUMO is large, the charge injection property is deteriorated, and thus the voltage of the element is increased.

By using the compound of the present invention having excellent balance of charge injection properties, it is possible to reduce the voltage and increase the efficiency of the organic EL device.

Hereinafter, an example of each of the above formula (A) will be described.

The alkyl group having a carbon number of 1 to 20 (preferably, a carbon number of 1 to 10, more preferably a carbon number of 1 to 6) has a linear or branched alkyl group, and specific examples thereof include a methyl group. Ethyl, propyl, isopropyl, N-butyl, isobutyl, secondary butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, etc., preferably exemplified by methyl, ethyl, propyl, isopropyl Base, n-butyl, isobutyl, secondary butyl, tert-butyl, more preferably methyl, ethyl, propyl, isopropyl, n-butyl, secondary butyl, tert-butyl.

Examples of the alkylene group having 1 to 20 carbon atoms include the divalent group of the above alkyl group.

Examples of the cycloalkyl group having 3 to 20 ring carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a 1-adamantyl group, a 2-adamantyl group, a 1-norbornyl group, and 2 - a thiol group or the like, preferably a cyclopentyl group or a cyclohexyl group.

The alkoxy group having 1 to 20 carbon atoms is represented by -OY ^a , and examples of the above alkyl group are exemplified as Y ^a . The alkoxy group is, for example, a methoxy group or an ethoxy group. The alkoxy group may be substituted by a fluorine atom, and in this case, a trifluoromethoxy group or the like is preferable.

The cycloalkyloxy group having 3 to 20 ring carbon atoms is represented by -OY ^b , and examples of the above cycloalkyl group are exemplified as Y ^b . The cycloalkoxy group is, for example, a cyclopentyloxy group or a cyclohexyloxy group.

The aromatic hydrocarbon ring group having 6 to 18 ring carbon atoms is preferably an aromatic hydrocarbon ring group having 6 to 12 ring carbon atoms.

Further, the term "ring-forming carbon" means a carbon atom constituting a saturated ring, an unsaturated ring, or an aromatic ring.

Specific examples of the monovalent aromatic hydrocarbon ring group include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthryl group, a condensed tetraphenyl group, and a fluorenyl group. Chrysenyl, benzo[c]phenanthryl, benzo[g] a phenyl group, a triphenylenyl group, a fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a biphenyl group, a triphenylene group, a tetraphenylene group, a propadienyl fluorenyl group, etc., preferably a benzene group. Base, biphenyl, terphenyl, tolyl, xylyl, naphthyl.

Specific examples of the divalent aromatic hydrocarbon ring group include a valent group of the above group.

The aryloxy group having 6 to 18 ring carbon atoms is represented by -OY ^c , and examples of the above aromatic hydrocarbon ring are exemplified as Y ^c . The aryloxy group is, for example, a phenoxy group.

The aromatic heterocyclic group having 5 to 18 ring atoms is preferably an aromatic heterocyclic group having 5 to 10 ring atoms.

Specific examples of the monovalent aromatic heterocyclic group include pyrrolyl group and pyridyl group. Base, pyridyl, pyrimidinyl, tri Base, sulfhydryl, isodecyl, imidazolyl, furyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, dibenzothiophenyl, azadibenzofuranyl, aza Dibenzothiophenyl, diazadibenzofuranyl, diazadibenzothiophenyl, quinolyl, isoquinolinyl, quin Orolinyl, oxazolyl, phenazinyl, acridinyl, morpholinyl, brown Thiophene Base base, Azolyl, A oxazolyl, a furazolyl group, a thienyl group, a benzothienyl group, a dihydroacridinyl group, an azacarbazolyl group, a diazacarbazolyl group, a quinazolinyl group, etc., preferably a pyridyl group or a pyrimidinyl group. three Base, dibenzofuranyl, dibenzothiophenyl, azadibenzofuranyl, azadibenzothiophenyl, diazadibenzofuranyl, diazadibenzothiophenyl, carbazole Base, azacarbazolyl, diazacarbazolyl.

The divalent aromatic heterocyclic group may, for example, be a divalent group of the above group.

Examples of the substituted or unsubstituted amino group include an amine group, an alkylamino group or a dialkylamino group having 1 to 10 carbon atoms (preferably having 1 to 6 carbon atoms), and a carbon number of 6 to 30 ( The arylamino group or the diarylamino group having a carbon number of 6 to 20, more preferably 6 to 10 carbon atoms, is preferable.

Examples of the substituted or unsubstituted fluorenyl group include a fluorenyl group, an alkyl group having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms), and a carbon number of 6 to 30 (preferably a carbon number of 6). ~20, more preferably an aryl fluorenyl group having 6 to 10 carbon atoms.

Specific examples of the alkyl fluorenyl group include a trimethyl fluorenyl group, a triethyl fluorenyl group, a tertiary dimethyl dimethyl fluorenyl group, a vinyl dimethyl fluorenyl group, a propyl dimethyl fluorenyl group, and the like. .

Specific examples of the arylsulfonyl group include a triphenylsulfonyl group, a phenyldimethylhydrazine group, a tertiary butyldiphenylfluorenyl group, a trimethylphenylindenyl group, and a tris(dimethylphenyl)fluorenyl group. , trinaphthyl fluorenyl and the like.

Examples of the substituent of the "substituted or unsubstituted ..." of the above respective groups include the above alkyl group, substituted or unsubstituted amino group, substituted or unsubstituted fluorenyl group, and aromatic group. An aromatic hydrocarbon ring group, a cycloalkyl group, an aromatic heterocyclic group, an alkoxy group, or another halogen atom (for example, fluorine, chlorine, bromine, iodine, etc., preferably a fluorine atom), a fluoroalkyl group, a hydroxyl group, Nitro, cyano, carboxyl, aryloxy and the like.

Further, among the hydrogen atoms in the compound of the present invention, isotopes having different numbers of neutrons, that is, protium, deuterium, and tritium, are contained.

Specific examples of the compound represented by the above formula (A) are shown below.

The method for producing the compound of the present invention is not particularly limited, and it may be produced by a known method. For example, a copper catalyst described in Tetrahedron No. 1435 to 1456 (1984) or J. Am. Chem. Soc can be used. The palladium catalyst described in pages 7727 to 7729 (2001) is produced by reacting a carbazole derivative with a halogenated aromatic compound. Also, according to the conditions described in the International Publication No. 2003-078541, International Publication No. 2011- Manufactured under the conditions described in Booklet No. 132684.

The compound of the present invention can be preferably used as a material for an organic electroluminescent device.

The material for an organic electroluminescent device of the present invention contains the compound of the present invention.

The material for an organic electroluminescent device of the present invention may contain only the compound of the present invention, and may contain other materials than the compound of the present invention.

Next, the organic EL device of the present invention will be described.

The organic EL device of the present invention has an organic thin film layer containing one or more layers of the light-emitting layer between the anode and the cathode. Further, at least one layer of the organic thin film layer contains the material for an organic EL device of the present invention.

Fig. 1 is a schematic view showing a layer configuration of an embodiment of an organic EL device of the present invention.

The organic EL element 1 has a structure in which an anode 20, a hole transporting region 30, a phosphorescent layer 40, an electron transporting region 50, and a cathode 60 are sequentially laminated on a substrate 10. The hole transfer region 30 means a hole transport layer and/or a hole injection layer or the like. Also, the electron transporting region 50 means an electron transporting layer and/or an electron injecting layer or the like. It is also possible not to form such a layer, and it is preferred to form one or more layers.

In the element 1, the organic thin film layer is provided on each of the organic layers on the hole transporting region 30, the phosphorescent layer 40, and the respective organic layers disposed on the electron transporting region 50. At least one of the organic thin film layers contains the material for an organic EL device of the present invention. Thereby, the organic EL element can be made highly efficient. Further, an organic EL element driven by a low voltage can be provided.

Further, the content of the material relative to the organic thin film layer containing the material for an organic EL device of the present invention is preferably from 1 to 100% by mass.

In the organic EL device of the present invention, the phosphorescent layer 40 preferably contains the material for an organic EL device of the present invention, and is preferably used as a host material for the light-emitting layer.

The triplet energy of the material for an organic EL device of the present invention is sufficiently large, so that the triplet energy of the phosphorescent dopant material can be efficiently used even if a blue phosphorescent dopant material is used. The ground is enclosed in the luminescent layer. Furthermore, it can be used not only for the blue light-emitting layer but also for the light-emitting layer of longer wavelength light (green to red, etc.).

Moreover, since the material for an organic EL device of the present invention is excellent in charge injection balance, it is possible to achieve high efficiency and low voltage drive of the organic EL device. Further, the material for an organic EL device of the present invention has an effect of increasing the life of the organic EL device by improving the charge balance.

The phosphorescent layer contains a phosphorescent material (phosphorescent dopant). As the phosphorescent dopant, a metal complex is exemplified, and a compound having a metal atom and a ligand selected from the group consisting of Ir, Pt, Os, Au, Cu, Re, and Ru is preferable. The ligand preferably has an ortho metal bond.

In order to increase the phosphorescence quantum yield and further improve the external quantum efficiency of the light-emitting element, the phosphorescent dopant is preferably a compound containing a metal atom selected from the group consisting of Ir, Os, and Pt, and is preferably a ruthenium complex. A metal complex such as a ruthenium complex or a platinum complex compound, more preferably a ruthenium complex and a platinum complex, is preferably an orthometalated ruthenium complex. The dopants may be used singly or in combination of two or more.

The concentration of the phosphorescent dopant in the phosphorescent layer is not particularly limited, but is preferably 0.1 to 30% by mass, and more preferably 0.1 to 20% by mass.

Further, it is also preferred to use the material for an organic EL device of the present invention in a layer adjacent to the phosphorescent layer 40. For example, when a layer containing the material of the present invention (anode side adjacent layer) is formed between the hole transport region 30 of the element of FIG. 1 and the phosphorescent layer 40, the layer functions as an electron barrier layer or as a function The function of the exciton blocking layer.

On the other hand, when a layer (cathode side adjacent layer) containing the material for an organic EL device of the present invention is formed between the phosphorescent layer 40 and the electron transporting region 50, the layer functions as a hole barrier layer or As a function of the exciton blocking layer.

In addition, the barrier layer (blocking layer) means a layer having a function of a moving barrier of a carrier or a diffusion barrier of an exciton. There are the following cases: mainly to prevent the electron self-luminous layer from leaking to the hole The organic layer of the transfer region is defined as an electron barrier layer, and the organic layer for preventing leakage of the hole from the light-emitting layer to the electron transport region is defined as a hole barrier layer. Further, there is a case where an organic layer is defined as an exciton blocking layer (triplet barrier layer) for preventing the triplet excitons generated in the light-emitting layer from having a triplet energy lower than that of the light-emitting layer The peripheral layer of the order spreads.

Further, the material for an organic EL device of the present invention can be used for a layer adjacent to the phosphorescent layer 40, and can be further used for another organic thin film layer bonded to a layer adjacent thereto.

The material for an organic EL device of the present invention can also be preferably used for an electron transport layer in the electron transporting region 50.

Further, in the case where two or more light-emitting layers are formed, the material for an organic EL device of the present invention can be preferably used for a spacer layer formed between the light-emitting layers.

Fig. 2 is a schematic view showing a layer configuration of another embodiment of the organic EL device of the present invention.

The organic EL element 2 is an example in which a mixed organic EL element having a phosphorescent layer and a fluorescent layer is laminated.

The organic EL element 2 has the same configuration as the above-described organic EL element 1 except that the spacer layer 42 and the fluorescent layer 44 are formed between the phosphorescent layer 40 and the electron transporting region 50. In the configuration in which the phosphorescent layer 40 and the fluorescent layer 44 are laminated, in order to prevent the excitons formed in the phosphorescent layer 40 from diffusing into the fluorescent layer 44, the phosphor layer 44 and the phosphorescent layer 40 are formed. The case of the spacer layer 42 is provided. Since the material for the organic EL device of the present invention has a large triplet energy, the layer of the material for an organic EL device of the present invention can function as a spacer layer.

In the organic EL element 2, for example, by using the phosphorescent layer 40 as a yellow light-emitting layer and the fluorescent layer 44 as a blue light-emitting layer, a white light-emitting organic EL device is obtained. Further, in the present embodiment, the phosphorescent layer 40 and the fluorescent layer 44 are formed layer by layer. However, the present invention is not limited thereto, and may be formed in two or more layers, and may be appropriately set depending on the use such as illumination or a display device. Further, in the case of using a white light-emitting element and a color filter to form a full-color light-emitting device, from the viewpoint of color rendering properties, it is preferable that a light-emitting region composed of one or more light-emitting layers is preferably It contains red, green, blue (RGB), and red, green, blue, yellow (RGBY) and other wavelength regions of the light.

In addition to the above-described embodiments, the organic EL device of the present invention may have various known configurations. Further, the light emission of the light-emitting layer can be extracted from the anode side, the cathode side, or both sides.

The organic EL device of the present invention is also preferably an interface region between the cathode and the organic thin film layer, and has at least one of an electron donating dopant and an organic metal complex.

According to such a configuration, improvement in luminance of the light emitted from the organic EL element or long life is achieved.

The electron-donating dopant may be at least one selected from the group consisting of an alkali metal, an alkali metal compound, an alkaline earth metal, an alkaline earth metal compound, a rare earth metal, and a rare earth metal compound.

The organic metal complex compound may be at least one selected from the group consisting of an alkali metal-containing organometallic complex, an alkaline earth metal-containing organometallic complex, and a rare earth metal-containing organometallic complex.

Examples of the alkali metal include lithium (Li) (work function: 2.93 eV), sodium (Na) (work function: 2.36 eV), potassium (K) (work function: 2.28 eV), and ruthenium (Rb) (work function). : 2.16 eV), 铯 (Cs) (work function: 1.95 eV), etc., preferably a work function of 2.9 eV or less. Among these, K, Rb, and Cs are preferable, and Rb or Cs is further preferable, and Cs is most preferable.

Examples of the alkaline earth metal include calcium (Ca) (work function: 2.9 eV), krypton (Sr) (work function: 2.0 eV or more and 2.5 eV or less), and barium (Ba) (work function: 2.52 eV), etc. The best work function is 2.9 eV or less.

Examples of the rare earth metal include cerium (Sc), cerium (Y), cerium (Ce), cerium (Tb), and ytterbium (Yb), and a work function of 2.9 eV or less is particularly preferable.

Among the above metals, a preferred metal has a particularly high reducing ability, and a relatively small amount is added to the electron injecting region, whereby the light-emitting luminance or the long life of the organic EL element can be improved.

Examples of the alkali metal compound include alkali metal oxides such as lithium oxide (Li ₂ O), cesium oxide (Cs ₂ O), and potassium oxide (K ₂ O), and lithium fluoride (LiF) and sodium fluoride (NaF). An alkali metal halide such as cesium fluoride (CsF) or potassium fluoride (KF) is preferably lithium fluoride (LiF), lithium oxide (Li ₂ O) or sodium fluoride (NaF).

Examples of the alkaline earth metal compound include barium oxide (BaO), strontium oxide (SrO), calcium oxide (CaO), and barium strontium citrate (Ba _x Sr _1-x O) (0<x<1) Barium strontium sulphate (Ba _x Ca _1-x O) (0 < x < 1), etc., preferably BaO, SrO, CaO.

Examples of the rare earth metal compound include yttrium fluoride (YbF ₃ ), yttrium fluoride (ScF ₃ ), cerium oxide (ScO ₃ ), yttrium oxide (Y ₂ O ₃ ), cerium oxide (Ce ₂ O ₃ ), and fluorine. GbF ₃ , TbF ₃ , etc., preferably YbF ₃ , ScF ₃ , TbF ₃ .

As described above, the organic metal complex is not particularly limited as long as it contains at least one of an alkali metal ion, an alkaline earth metal ion, and a rare earth metal ion as a metal ion. Further, the ligand is preferably quinolol, benzoquinolol, acridinol, phenanthridinol, hydroxyphenyl Oxazole, hydroxyphenylthiazole, hydroxydiaryl Diazole, hydroxydiarylthiadiazole, hydroxyphenylpyridine, hydroxyphenylbenzimidazole, hydroxybenzotriazole, hydroxyfluoroborane, bipyridine, morpholine, phthalocyanine, porphyrin, cyclopentadiene And β-diketones, methylimines, and the like, but are not limited thereto.

The addition form of the electron donating dopant and the organometallic complex is preferably formed into a layered or island shape in the interface region. As a method of forming, it is preferable to use a resistance heating deposition method to vaporize at least one of an electron-donating dopant and an organic metal complex while simultaneously forming a light-emitting material forming an interface region or The electron injecting material, that is, the organic material, is vapor-deposited, and at least one of the electron-donating dopant and the organic metal complex is dispersed in the organic substance. The dispersion concentration is usually organic in terms of molar ratio: electron donating dopant and/or organometallic complex = 100:1 to 1:100, preferably 5:1 to 1:5.

When at least one of the electron donating dopant and the organic metal complex is formed into a layered shape, the luminescent material or the electron injecting material of the organic layer as the interface is formed into a layer shape, and then resistance heating is used alone. Evaporation method for electron donating dopants and organometallic complexes At least one of the vapor deposition is preferably formed to have a thickness of the layer of 0.1 nm or more and 15 nm or less.

When at least one of the electron-donating dopant and the organic metal complex is formed into an island shape, the luminescent material or the electron injecting material of the organic layer as the interface is formed into an island shape, and then resistance heating is used alone. The vapor deposition method vapor-deposits at least one of the electron donating dopant and the organic metal complex, and is preferably formed to have a thickness of the island of 0.05 nm or more and 1 nm or less.

Moreover, the ratio of the main component of the organic EL device of the present invention to at least one of the electron-donating dopant and the organic metal complex is preferably a molar ratio of the main component: electron-donating The impurity and/or organometallic complex = 5:1 to 1:5, and more preferably 2:1 to 1:2.

In the organic EL device of the present invention, the configuration other than the layer of the material for an organic EL device of the present invention is not particularly limited, and a known material or the like can be used. Hereinafter, the layer of the element of one embodiment will be briefly described. However, the material applied to the organic EL element of the present invention is not limited to the following.

[substrate]

As the substrate, a glass plate, a polymer plate, or the like can be used.

Examples of the glass plate include soda lime glass, bismuth- and bismuth-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium boric acid glass, and quartz. Further, examples of the polymer sheet include polycarbonate, acrylic acid, polyethylene terephthalate, polyether oxime, and polyfluorene.

[anode]

The anode is made of, for example, a conductive material, preferably a conductive material having a work function of more than 4 eV.

Examples of the conductive material include carbon, aluminum, vanadium, iron, cobalt, nickel, tungsten, silver, gold, platinum, palladium, etc., and the like, and tin oxide and oxygen used in the ITO substrate and the NESA substrate. An oxidized metal such as indium oxide, or an organic conductive resin such as polythiophene or polypyrrole.

The anode may be formed by a layer of two or more layers as needed.

[cathode]

The cathode is made of, for example, a conductive material, preferably a conductive material having a work function of less than 4 eV.

Examples of the conductive material include magnesium, calcium, tin, lead, titanium, lanthanum, lithium, lanthanum, manganese, aluminum, lithium fluoride, and the like, but are not limited thereto.

In addition, examples of the alloy include magnesium/silver, magnesium/indium, and lithium/aluminum as representative examples, but are not limited thereto. The ratio of the alloy is controlled according to the temperature, environment, degree of vacuum, etc. of the vapor deposition source, and an appropriate ratio is selected.

The cathode may be formed by a layer of two or more layers, and the cathode may be formed by forming a thin film by a method such as vapor deposition or sputtering.

In the case where light emitted from the light-emitting layer is extracted from the cathode, the transmittance of the light emission to the cathode is preferably more than 10%.

Further, the sheet resistance as the cathode is preferably several hundred Ω/□ or less, and the film thickness is usually from 10 nm to 1 μm, preferably from 50 to 200 nm.

[Light Emitting Layer]

In the case where a phosphorescent layer is formed of a material other than the material of the organic EL device layer of the present invention, a known material can be used as the material of the phosphorescent layer. Specifically, it is sufficient to refer to Japanese Patent Application No. 2005-517938 and the like.

The organic EL device of the present invention may have a fluorescent layer as in the element shown in FIG. As the fluorescing layer, a known material can be used.

The luminescent layer can be made into a double body (also known as a body, co-host). Specifically, in the light-emitting layer, the carrier balance in the light-emitting layer can be adjusted by combining the main body of the electron transport property and the body of the hole transport property.

Also, a double dopant can be produced. In the light-emitting layer, each dopant is caused to emit light by adding two or more dopant materials having a high quantum yield. For example, there is a case where a yellow light-emitting layer is realized by co-evaporating a host with a red dopant and a green dopant.

The light-emitting layer may be a single layer or a laminated structure. When the light-emitting layer is laminated, the recombination region can be concentrated on the light-emitting layer interface by accumulating electrons and holes in the interface of the light-emitting layer. Thereby, the quantum efficiency is improved.

[hole injection layer and hole transmission layer]

The hole injection and transport layer helps to inject holes into the light-emitting layer and transmit them to the layer of the light-emitting region, and the mobility of the holes is large, and the ionization energy is usually less than 5.6 eV.

As a material for the hole injection and transport layer, it is preferable to transfer the hole to the material of the light-emitting layer with a lower electric field strength, and further, the mobility of the hole is, for example, when an electric field of 10 ⁴ to 10 ⁶ V/cm is applied. Preferably, it is at least 10 ^-4 cm ² /V. s.

Specific examples of the material for the hole injection and transport layer include a triazole derivative (refer to the specification of U.S. Patent No. 3,112,197, etc.), An oxadiazole derivative (refer to the specification of U.S. Patent No. 3,189,447, etc.), an imidazole derivative (refer to Japanese Patent Publication No. Sho 37-16096, etc.), a polyarylalkane derivative (refer to the specification of U.S. Patent No. 3,615,402, U.S. Patent No. 3,820,989) Japanese Patent No. 3,542,544, Japanese Patent Publication No. Sho 45-555, Japanese Patent Publication No. 51-10983, Japanese Patent Laid-Open No. 51-93224, Japanese Patent Laid-Open No. 55-17105, and Japanese Patent Laid-Open Japanese Patent Publication No. Sho 55-108667, JP-A-55-156953, JP-A-55-156656, JP-A-56-36656, etc., pyrazoline derivatives and pyrazolone derivatives ( U.S. Patent No. 3,180,729, U.S. Patent No. 4,278,746, Japanese Patent Laid-Open No. Hei 55-88064, Japanese Patent Laid-Open No. 55-88065, Japanese Patent Laid-Open No. SHO-49-105537, and Japanese Patent Laid-Open No. 55 Japanese Unexamined Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. -74546, etc.), benzene A diamine derivative (refer to the specification of U.S. Patent No. 3,615,404, Japanese Patent Publication No. 51-10105, Japanese Patent Publication No. Sho 46-3712, Japanese Patent Publication No. Sho 47-25336, Japanese Patent Publication No. Sho 54-119925, etc.) And arylamine derivatives (refer to the specification of U.S. Patent No. 3,567,450, U.S. Patent No. 3,240,597, U.S. Patent No. 3,658,520, U.S. Patent No. 4,232,103, U.S. Patent No. 4,175,961, U.S. Patent No. 4,012,376, Japanese Patent Publication No. Sho 49-35702, Japanese Patent Publication No. Sho 39-27577, Japanese Laid-Open Patent Publication No. 55-144250, Japanese Patent Laid-Open No. Hei 56-119132, Japanese Patent Laid-Open No. 56-22437, and Patent No. 1,110,518, etc.), an amine-substituted chalcone derivative (refer to the specification of U.S. Patent No. 3,526,501, etc.), An azole derivative (expressed in the specification of the U.S. Patent No. 3,257,203, etc.), a styrene-based hydrazine derivative (refer to JP-A-56-46234, etc.), an anthrone derivative (refer to Japanese Patent Laid-Open No. 54-110837)公报 公报 等 ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( Japanese Patent Publication No. Sho 55-46760, JP-A-57-11350, JP-A-57-148749, JP-A No. 2-311591, etc., and anthracene derivatives (see Japanese Patent Laid-Open No. 61-210363) Japanese Laid-Open Patent Publication No. 61-228451, Japanese Patent Laid-Open No. 61-14642, Japanese Patent Laid-Open No. 61-72255, Japanese Patent Laid-Open No. 62-47646, and Japanese Patent Laid-Open No. 62- Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. Japanese Patent Publication No. 174749, JP-A-60-175052, etc., decazane derivatives (U.S. Patent No. 4,950) Japanese Patent Laid-Open No. Hei No. 2-204996, and an aniline copolymer (Japanese Patent Laid-Open No. Hei 2-282263).

Further, an inorganic compound such as p-type Si or p-type SiC can also be used as a hole injecting material.

The material of the hole injection and transport layer can be made of a crosslinked type material as a crosslinked type. The hole is injected into the transport layer, and for example, by heat, light, etc., Chem. Mater. 2008, 20, 413-422, Chem. Mater. 2011, 23 (3), 658-681, WO2008108430, WO2009102027, WO2009123269, WO2010016555, WO2010018813 The crosslinked material is passed through an insoluble layer.

[Electronic injection layer and electron transport layer]

The electron injection and transport layer facilitates electron injection into the light-emitting layer, is transmitted to the layer of the light-emitting region, and is a layer having a large electron mobility.

It is known that an organic EL element reflects light emitted by an electrode (for example, a cathode), and thus interferes with light emitted directly from the anode and light emitted by reflection by an electrode. In order to utilize the interference effect efficiently, the electron injection and transport layers are appropriately selected in a film thickness of several nm to several μm, but in particular, when the film thickness is thick, in order to avoid voltage rise, 10 ⁴ to 10 ⁶ V/cm is applied. In the electric field, the electron mobility is preferably at least 10 ^-5 cm ² /Vs or more.

As the electron transporting material used in the electron injecting and transporting layer, an aromatic heterocyclic compound containing one or more hetero atoms in the molecule can be preferably used, and a nitrogen-containing ring derivative is particularly preferable. Further, the nitrogen-containing ring derivative is preferably an aromatic ring having a nitrogen-containing 6-membered ring or a 5-membered ring skeleton, or a condensed aromatic ring compound having a nitrogen-containing 6-membered ring or a 5-membered ring skeleton, and examples thereof include The skeleton contains a pyridine ring, a pyrimidine ring, and three a compound such as a ring, a benzimidazole ring, a phenanthroline ring, or a quinazoline ring.

Further, an organic layer having semiconductivity may be formed by doping (n) of a donor material or doping (p) of an acceptor material. A representative example of N doping is in which an electron transporting material is doped with a metal such as Li or Cs, and a representative example of P doping is doped with a F4TCNQ (2, 3, 5, 6- in a hole transporting material). Receptor materials such as Tetrafluoro-7, 7, 8, 8-tetracyanoquinodimethane) (for example, refer to Japanese Patent No. 3695714).

The formation of each layer of the organic EL device of the present invention can be carried out by a dry film formation method such as vacuum deposition, sputtering, plasma or ion plating, or a wet film formation method such as spin coating, dipping or flow coating. Know the method.

The film thickness of each layer is not particularly limited, but it must be set to an appropriate film thickness. If the film thickness is too thick, in order to obtain a constant light output, a large applied voltage is necessary and the efficiency is deteriorated. When the film thickness is too small, pinholes or the like are generated, and sufficient light emission luminance cannot be obtained even if an electric field is applied. The film thickness is usually in the range of 5 nm to 10 μm, and more preferably in the range of 10 nm to 0.2 μm.

Example Synthesis Example 1 [Synthesis of Compound A]

(1) Synthesis of intermediate A

Intermediate A was synthesized by the following procedure.

Under argon, carbazole 16.7 g (100 mmol), 3,5-dibromopyridine 23.7 g (100 mmol), copper iodide 19.0 g (100 mmol), trans 1,2-cyclohexanediamine 11.4 g (100 mmol), tripotassium phosphate 42.4 g (200 mmol) added to dehydrated 1,4-two The mixture was heated under reflux for 96 hours in 200 ml of alkane. To the residue obtained by concentrating the reaction solution under reduced pressure, 500 ml of toluene was added, and the mixture was heated to 120 ° C, and the insoluble matter was separated by filtration. The residue obtained by concentrating the filtrate under reduced pressure using a hydrazine column chromatography (hexane/toluene = 4/1 (volume ratio)) was purified to obtain a white solid intermediate A6.8 g (yield twenty one%).

(2) Synthesis of Compound A

Compound A was synthesized by the following procedure.

Intermediate B4.08 g (10 mmol), intermediate A3.23 g (10 mmol), Pd ₂ (dba) ₃ (three (two) synthesized under the argon atmosphere by the method described in EP1972619 Tris (dibenzylideneacetone dipalladium)) 0.18 g (0.2 mmol), tris-tert-butyl tetrafluoroborate (t-Bu ₃ P-HBF ₄ ) 0.23 g (0.8 mmol), three Sodium butoxide (t-BuONa) 1.35 g (14 mmol) was added to 40 ml of dehydrated xylene, and stirred under reflux for 24 hours. To the residue obtained by concentrating the reaction solution under reduced pressure, 400 ml of toluene was added, and the mixture was heated to 120 ° C, and the insoluble matter was separated by filtration. The residue obtained by concentrating the filtrate under reduced pressure using a hydrazine column chromatography (hexane/ethyl acetate = 3/1 (volume ratio)) was purified to obtain a compound A2.9 g of a white solid. Rate 45%).

The results of the FD-MS analysis were identified as Compound A with respect to a molecular weight of 650 (calculated value) of m/e = 650 (measured value).

Synthesis Example 2 [Synthesis of Compound B]

(1) Synthesis of intermediate C

Intermediate C was synthesized by the following procedure.

Under argon, carbazole 16.7 g (100 mmol), 2,6-dibromopyridine 23.7 g (100 mmol), copper iodide 19.0 g (100 mmol), trans 1,2-cyclohexanediamine 11.4 g (100 mmol), tripotassium phosphate 42.4 g (200 mmol) added to dehydrated 1,4-two The mixture was heated under reflux for 72 hours in 200 ml of alkane. To the residue obtained by concentrating the reaction solution under reduced pressure, 500 ml of toluene was added, and the mixture was heated to 120 ° C, and the insoluble matter was separated by filtration. The residue obtained by concentrating the filtrate under reduced pressure using a hydrazine column chromatography (hexane/toluene = 4/1 (volume ratio)) was purified to obtain a white solid intermediate C 9.7 g (yield 30%).

(2) Synthesis of Compound B

Compound B was synthesized by the following procedure.

Intermediate B4.08 g (10 mmol), intermediate C3.23 g (10 mmol), Pd ₂ (dba) ₃ 0.18 g (0.2 mmol) and tris-trifluorotetrafluoroborate under argon atmosphere 0.23 g (0.8 mmol) and 1.35 g of sodium tert-butoxide (14 mmol) were added to 40 ml of dehydrated xylene, and the mixture was stirred under reflux for 24 hours. To the residue obtained by concentrating the reaction solution under reduced pressure, 400 ml of toluene was added, and the mixture was heated to 120 ° C, and the insoluble matter was separated by filtration. The residue obtained by concentrating the filtrate under reduced pressure using a hydrazine column chromatography (hexane/toluene = 2/1 (volume ratio)) was purified to obtain a compound B 3.6 g (yield 55) as a white solid. %).

The results of the FD-MS analysis were identified as Compound B with respect to a molecular weight of 650 (calculated value) of m/e = 650 (measured value).

Synthesis Example 3 [Synthesis of Compound C]

(1) Synthesis of intermediate D

Add 2-nitroiodobenzene 12.4 g (49.8 mmol), 2-bromophenylboronic acid 10 g (49.8 mmol), 2 M sodium carbonate aqueous solution 75 ml, toluene 70 ml, 1,2-two under argon atmosphere 70 ml of methoxyethane (DME), and then 1.14 g (1 mmol) of tetrakis(triphenylphosphine)palladium was added, and the mixture was stirred under reflux for 24 hours. After adding 1000 ml of toluene and 200 ml of water, the organic phase was separated and concentrated under reduced pressure. The residue obtained was purified by a silica gel column chromatography (hexane / toluene = 4 / 1 (volume ratio)) to obtain a white solid D12.9 g (yield: 93%).

(2) Synthesis of intermediate E

Under an argon atmosphere, an intermediate D12.9 g (46.4 mmol), triphenylphosphine 30.5 g (116 mmol), and o-dichlorobenzene 100 ml were added, and the mixture was stirred under reflux for 12 hours. The reaction liquid was directly purified by adding to a silica gel column chromatography (hexane/toluene=4/1 (volume ratio)) to obtain an intermediate E4.3 g (yield 38%) as a white solid.

(3) Synthesis of intermediate F

Under an argon atmosphere, add 23.2 g (80.8 mmol) of N-phenylcarbazole-3-borate, intermediate E19.9 g (80.8 mmol), 2 M sodium carbonate aqueous solution 120 ml, 1,2-dimethoxy 400 ml of ethane (DME), then 1.9 g (1.64 mmol) of tetrakis(triphenylphosphine)palladium was added, and the mixture was stirred under reflux for 12 hours. After adding 1000 ml of toluene and 200 ml of water, the organic phase was separated and concentrated under reduced pressure. Using a silicone column chromatography (hexane/toluene = 4/1 (volume ratio)) The slag was purified, and n-hexane was added to precipitate a solid, whereby a white solid intermediate F25.4 g (yield: 77%) was obtained.

(4) Synthesis of Compound C

Intermediate F4.08 g (10 mmol), intermediate A3.23 g (10 mmol), Pd ₂ (dba) ₃ 0.18 g (0.2 mmol) and tris-trifluorotetrafluoroborate under argon atmosphere 0.23 g (0.8 mmol) and 1.35 g of sodium tert-butoxide (14 mmol) were added to 40 ml of dehydrated xylene, and the mixture was stirred under reflux for 24 hours. To the residue obtained by concentrating the reaction solution under reduced pressure, 400 ml of toluene was added, and the mixture was heated to 120 ° C, and the insoluble matter was separated by filtration. The residue obtained by concentrating the filtrate under reduced pressure using a hydrazine column chromatography (hexane/ethyl acetate = 4/1 (volume ratio)) was purified to obtain a compound C3.6 g of a white solid. Rate 55%).

The results of the FD-MS analysis were identified as Compound C with respect to a molecular weight of 650 (calculated value) of m/e = 650 (measured value).

Synthesis Example 4 [Synthesis of Compound D]

Intermediate F4.08 g (10 mmol), intermediate C3.23 g (10 mmol), Pd ₂ (dba) ₃ 0.18 g (0.2 mmol) and tris-trifluorotetrafluoroborate under argon atmosphere 0.23 g (0.8 mmol) and a third grade sodium butoxide 1.35 g (14 mmol) were added to 40 ml of anhydrous xylene, and the mixture was stirred under reflux for 24 hours. To the residue obtained by concentrating the reaction solution under reduced pressure, 400 ml of toluene was added, and the mixture was heated to 120 ° C, and the insoluble matter was separated by filtration. The residue obtained by concentrating the filtrate under reduced pressure using a hexane-purified column chromatography (hexane/ethyl acetate = 3/1 (volume ratio) was purified to obtain a white solid compound D2.5 g (yield 38%).

The results of the FD-MS analysis were identified as Compound D with respect to a molecular weight of 650 (calculated value) of m/e = 650 (measured value).

Evaluation Example 1 [Measurement of free potential (Ip)]

The free potential (Ip) of the compounds A to D was measured under a atmosphere using a photoelectron spectroscopic device (manufactured by Riken Keiki Co., Ltd.: AC-3). Specifically, the compounds A to D were irradiated with light, and the amount of electrons generated by charge separation at this time was measured and calculated. The measurement results of the free potentials of the compounds A to D are shown in Table 1.

Further, the measurement results of the free potentials of the following compounds H-1 and H-2 are shown in Table 1.

As shown in Table 1, the compound of the present invention diffuses the distribution of HOMO by linking the carbazole ring, and exists in The separation of the LUMO of the ring becomes large, so the value of Ip becomes small.

Specifically, the electron cloud distributions of HOMO and LUMO of compounds A, B, compounds H-1 and H-2 calculated by using Gaussian 98 (manufactured by Gaussian) at the B3LYP/6-31G*opt level are shown in the figure. 3~6. 3 and 4, the following are known about the compounds A and B.

. The two carbazole rings (Cz) are linked by a pyridine ring as a nitrogen-containing six-membered ring, and the π-conjugated system is cleaved by a nitrogen-containing six-membered ring, so that π electrons are not diffused to the entire Cz-Az-Cz. Thereby, there is a higher T1 energy level.

. The distribution of HOMO is diffused onto Cz-Cz by bonding to one of the carbazole rings (Cz) of the pyridine ring and further bonding another carbazole ring (Cz). Thereby, the hole injection property is improved.

. HOMO is distributed on Cz-Cz, and LUMO is distributed on the nitrogen-containing six-membered ring, and HOMO is separated from LUMO. Thereby, the charge injection property is improved.

As can be seen from the above, the balance between the injection side and the electron side of the compounds A and B is excellent, and the voltage of the element can be reduced and the efficiency can be improved.

On the other hand, as shown in Fig. 5, the compound H-1 has a large degree of overlap between HOMO and LUMO. Therefore, the charge injectability is lowered as compared with the compounds A and B. It is understood that the actual Ip measurement value is also larger than the compound of the present invention, and the compound H-1 and H-2 also represent a larger value, and the charge injection barrier is larger.

Example 1

(1) Production of organic EL elements

A 25 mm × 75 mm × 1.1 mm glass substrate (made by Geomatec) with an ITO transparent electrode was subjected to ultrasonic cleaning for 5 minutes in isopropyl alcohol, and further, UV (Ultraviolet) ozone was applied for 30 minutes. Wash.

The glass substrate with the transparent electrode thus washed is mounted on the vacuum evaporation device In the substrate holder, first, the following compound I was vapor-deposited to a thickness of 20 nm so as to cover the transparent electrode on the surface on which the transparent electrode line was formed on the glass substrate to form a hole injection layer. Then, on the hole injection layer, the following compound II was vapor-deposited at a thickness of 60 nm to form a hole transport layer.

On the hole transport layer, the compound A obtained in Synthesis Example 1 as a phosphorescent host compound and the following compound D-1 as a phosphorescent material were co-deposited at a thickness of 50 nm to form a phosphorescent layer. The concentration of the compound A in the phosphorescent layer was 80% by mass, and the concentration of the compound D-1 was 20% by mass.

Then, on the phosphorescent layer, the following compound H-3 was deposited at a thickness of 10 nm to form an electron transport layer 1. Further, on the electron transport layer 1, the following compound III was deposited at a thickness of 10 nm to form an electron transport layer 2, and then a layer of LiF having a thickness of 1 nm and a thickness of 80 nm were sequentially deposited on the electron transport layer 2. Metal Al forms a cathode. Further, LiF as an electron injecting electrode was formed at a rate of 1 □/min.

(2) Evaluation of luminescence properties of organic EL elements

The produced organic EL element was driven to emit light by a DC current, and the luminance and current density were measured to determine the voltage at a current density of 1 mA/cm ² and the luminous efficiency (external quantum efficiency). The evaluation results of these luminescent properties are shown in Table 2.

Example 2

An organic EL device was produced in the same manner as in Example 1 except that the compound A was used instead of the compound H-3 as the compound of the electron-transporting layer 1, and the luminescent properties were evaluated. The results are shown in Table 2.

Further, a luminance of 70% of the initial luminance of 3,000 cd/m ^{2 was} obtained (the luminance was reduced to 70% of the initial luminance). The results of the 70% brightness life are shown in Table 3.

Example 3

An organic EL device was produced and evaluated in the same manner as in Example 1 except that the compound B was used instead of the compound A as the light-emitting layer host compound. The results are shown in Table 2.

Example 4

An organic EL device was produced and evaluated in the same manner as in Example 1 except that the compound B was used as the compound of the electron-transporting layer 1 and the compound B was used instead of the compound H-3. . Further, the luminance 70% life was evaluated in the same manner as in the second embodiment. The results are shown in Tables 2 and 3.

Example 5

An organic EL device was produced and evaluated in the same manner as in Example 1 except that the compound C was used instead of the compound A as the light-emitting layer host compound. The results are shown in Table 2.

Example 6

An organic EL device was produced and evaluated in the same manner as in Example 1 except that the compound C was used as the compound of the electron-transporting layer 1 and the compound C was used instead of the compound H-3. . The results are shown in Table 2.

Example 7

An organic EL device was produced in the same manner as in Example 1 except that the compound H-4 was used as the compound of the electron-transporting layer 1 as the compound of the electron-emitting layer 1 and the compound A was used instead of the compound H-3. Conduct an evaluation. The results are shown in Table 2.

Example 8

An organic EL device was produced in the same manner as in Example 1 except that the compound H-4 was used as the compound of the electron-transporting layer 1 as the compound of the electron-emitting layer 1 and the compound B was used instead of the compound H-3. Conduct an evaluation. The results are shown in Table 2.

Example 9

As the light-emitting layer host compound, compound H-4 is used instead of compound A as an electron transfer. An organic EL device was produced and evaluated in the same manner as in Example 1 except that the compound of the layer 1 was used instead of the compound H-3. The results are shown in Table 2.

Comparative example 1

An organic EL device was produced in the same manner as in Example 1 except that the compound H-1 was used as the compound of the electron-transporting layer 1 as the compound of the electron-emitting layer 1 and the compound H-1 was used instead of the compound H-3. And evaluate. Further, the luminance 70% life was evaluated in the same manner as in the second embodiment. The results are shown in Tables 2 and 3.

Comparative example 2

An organic EL device was produced in the same manner as in Example 1 except that the compound H-2 was used as the compound of the electron-transporting layer 1 as the compound of the electron-emitting layer 1 and the compound H-2 was used instead of the compound H-3. And evaluate. Further, the luminance 70% life was evaluated in the same manner as in the second embodiment. The results are shown in Tables 2 and 3.

Comparative example 3

An organic EL device was produced in the same manner as in Example 1 except that the compound H-4 was used as the compound of the electron-transporting layer 1 as the compound of the electron-emitting layer 1 and the compound H-1 was used instead of the compound H-3. And evaluate. The results are shown in Table 2.

Comparative example 4

An organic EL device was produced in the same manner as in Example 1 except that the compound H-4 was used as the compound of the electron-transporting layer 1 as the compound of the electron-emitting layer 1 and the compound H-2 was used instead of the compound H-3. And evaluate. The results are shown in Table 2.

The elements of Examples 1 to 9 were more efficient than the elements of Comparative Examples 1 to 4 by the improvement of charge balance. Further, since the elements of Examples 1 to 9 have improved hole injectability and electron injectability, they are further reduced in voltage. In particular, when the compound of the present invention is used as a host material in the light-emitting layer, the effect of increasing the life of the charge balance is large.

[Industrial availability]

The compound of the present invention can be used as a material for an organic EL device. The organic EL device of the present invention can be used for a planar light-emitting body such as a flat panel display of a wall-mounted television, a backlight of a photocopier, a printer, a backlight of a liquid crystal display, a light source such as a gauge, a display panel, an indicator lamp, or the like.

Several embodiments and/or embodiments of the invention have been described in detail above. It is to be understood that various modifications may be made in the embodiments and/or embodiments of the embodiments described herein without departing from the invention. Accordingly, such various modifications are intended to be included within the scope of the present invention.

The contents of the documents described in the present specification and the Japanese application specification which is the basis of the priority of the Paris Convention of the present application are hereby incorporated by reference.

Claims (17)

A compound represented by the following formula (A): In (in Formula _{(A), Y 1 ~ Y} 5 each independently represent a carbon CR _1, a nitrogen atom, or Cz bonding of atoms, Y ₁ ~ Y ₅ in the at least one nitrogen atom; in R ₁ is present In the case of plural cases, a plurality of R _{1 's} may be the same or different from each other; m is an integer of 1 to 3, and when m is 2 or more, a plurality of Cz may be the same or different from each other; Y ₁₁ to Y ₁₄ respectively independently carbon atom CR _2, a nitrogen atom, or A key knot, Y ₁₅ ~ Y ₁₈ each independently CR ₂ or a nitrogen atom; to when R ₂ is present case plural, the plural R ₂ s each may be the same Y ₂₁ ~Y ₂₄ are independently CR ₃ , a nitrogen atom, or a carbon atom bonded to A, and Y ₂₅ ~Y ₂₈ are independently CR ₃ or a nitrogen atom; respectively, there are a plurality of R ₃ In the case, a plurality of R _{3 's} may be the same or different from each other; R ₁ to R ₃ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, substituted or unsubstituted. a cycloalkyl group having 3 to 20 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms, substituted Or unsubstituted ring carbon 6 to 18 aromatic hydrocarbon ring groups, substituted or unsubstituted aryloxy groups having 6 to 18 ring carbon atoms, substituted or unsubstituted aromatic heterocyclic groups having 5 to 18 ring atoms; a substituted or unsubstituted amino group, a substituted or unsubstituted fluorenyl group, a fluoro group, or a cyano group; and Ar is a substituted or unsubstituted aromatic hydrocarbon ring group having 6 to 18 carbon atoms; Or a substituted or unsubstituted aromatic heterocyclic group having 5 to 18 ring atoms; A is a single bond, a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, substituted or unsubstituted An aromatic hydrocarbon ring group having 6 to 18 carbon atoms or a substituted or unsubstituted aromatic heterocyclic group having 5 to 18 ring atoms; wherein, when A is a single bond, Y ₁₁ Any one of Y Y ₁₄ is directly bonded to any one of Y ₂₁ to Y ₂₄ ; and Cz is a nitrogen-containing polycyclic group represented by any one of the following formulas (1) to (5); (In the formulae (1) to (5), X ₁ to X ₈ are each independently CR _a or a nitrogen atom, and Z is a single bond, an oxygen atom, a sulfur atom, -S(=O)-, -S (= O) ₂ -, -Si(R _c R _d )-, -C(R _e R _f )-, or -N(R _g )-, R _a ~R _g are each independently the same group as R ₁ , when the presence of a plurality of in case of R _a, plural R _a may be identical or different from each other; the position shown in Cz * nitrogen-containing Y ₁ ~ Y ₅ of the six-membered rings bonded)). The compound of claim 1, wherein at least one of Y ₂ and Y ₄ is a nitrogen atom. The compound of claim 1, wherein at least one of Y ₁ and Y ₅ is a nitrogen atom. The compound of claim 1, wherein only one of Y ₁ to Y ₅ is a nitrogen atom. The compound of any one of claims 1 to 4, wherein Z is a single bond. The compound of any one of claims 1 to 4, wherein Cz is a nitrogen-containing polycyclic group represented by the formula (1). The compound of any one of claims 1 to 4, wherein Cz is a nitrogen-containing polycyclic group represented by the formula (4). The compound of any one of claims 1 to 4, wherein A is a single bond. The compound of any one of claims 1 to 4, wherein Y ₂ or Y ₄ is a carbon atom bonded to Cz. A material for an organic electroluminescent device, which comprises the compound of any one of claims 1 to 9. An organic electroluminescence device having an organic thin film layer including one or more layers of a light-emitting layer between a cathode and an anode, wherein at least one of the organic thin film layers contains a material for an organic electroluminescence device according to claim 10 of the patent application. The organic electroluminescent device of claim 11, wherein the luminescent layer contains the material for the organic electroluminescent device. The organic electroluminescent device of claim 11 or 12, wherein the luminescent layer comprises a phosphorescent material. The organic electroluminescent device of claim 13, wherein the phosphorescent material is an ortho-metalated complex of a metal atom selected from the group consisting of iridium (Ir), osmium (Os), and platinum (Pt). An organic electroluminescent device according to claim 11, wherein the cathode and the luminescence There is an organic thin film layer between the layers, and the organic thin film layer contains the material for the organic electroluminescence element. The organic electroluminescent device of claim 15, wherein the organic thin film layer is an electron transport layer. An organic electroluminescent device according to claim 11, wherein an organic thin film layer is provided between the anode and the light-emitting layer, and the organic thin film layer contains the material for the organic electroluminescent device.