WO2012133649A1

WO2012133649A1 - Charge transport material, organic electroluminescence element, light-emitting device, display apparatus, and illumination apparatus

Info

Publication number: WO2012133649A1
Application number: PCT/JP2012/058355
Authority: WO
Inventors: 渡辺　康介; テンカ欧陽
Original assignee: 富士フイルム株式会社
Priority date: 2011-03-31
Filing date: 2012-03-29
Publication date: 2012-10-04
Also published as: JP5906114B2; JP2012216820A

Abstract

A charge transport material, which has a structure indicated by the following formula, and which comprises a compound containing 6-19 monocyclic aromatic rings (the members of the aromatic ring are carbon atoms or nitrogen atoms, and the number of ring members is 6), has a low driving voltage and excellent durability (R¹¹¹-R¹²⁸ indicate hydrogen atoms or substituents thereof. At least one of R¹¹¹-R¹²² is a cyano group. However, not all of three continuous benzene rings will each have a cyano group, and a benzene ring having a cyano group will not be substituted by three or more benzene rings).

Description

Charge transport material, organic electroluminescent element, light emitting device, display device and lighting device

The present invention relates to a charge transport material, an organic electroluminescent element, a light emitting device, a display device, and a lighting device.

Organic electroluminescent elements (hereinafter also referred to as “elements” and “organic EL elements”) are actively researched and developed because they can emit light with high luminance when driven at a low voltage. An organic electroluminescent element has an organic layer between a pair of electrodes, and electrons injected from the cathode and holes injected from the anode recombine in the organic layer, and the generated exciton energy is used for light emission. To do.

In recent years, the use of phosphorescent light-emitting materials has advanced the efficiency of devices. Patent Document 1 discloses the use of a benzonitrile-based charge transport material having a substituent at the ortho position for further improving the light emission efficiency of the device and reducing the driving voltage.

JP 2007-266598 A

As a result of studies by the present inventors, it has been clarified that in the conventional element described in Patent Document 1, the driving voltage is too high and there is a problem in durability. In particular, the devices using comparative compounds 1 to 5 shown in Examples described later, which have been reported so far, all have problems such as excessive driving voltage and low durability. there were.

That is, an object of the present invention is to provide a charge transport material having a low driving voltage and good durability.
Another object of the present invention is to provide an organic electroluminescent device using the charge transport material. Furthermore, another object of the present invention is to provide a light emitting device, a display device, and a lighting device including the organic electroluminescent element of the present invention.

According to the study by the present inventors, the use of a compound having a specific p-terphenyl structure and a larger number of monocyclic aromatic rings than the compound described in Patent Document 1 as a charge transporting material enables low driving. It has been found that an organic electroluminescent device having a good voltage and durability is provided.

That is, the present invention can be achieved by the following means.
[1] A charge transport material having a structure represented by the following general formula (1) and comprising a compound containing 6 to 19 monocyclic benzene rings.
General formula (1)

(In the general formula (1), R ¹¹¹ to R ¹²⁸ each represent a hydrogen atom or a substituent. At least one of R ¹¹¹ to R ¹²² is a cyano group, provided that each of the three consecutive benzene rings has a cyano group. The benzene ring having a cyano group is not substituted with three or more benzene rings.
[2] The charge transport material according to [1], wherein one or two of R ¹¹¹ to R ¹²⁸ in the general formula (1) are cyano groups.
[3] The charge transport material according to [1] or [2], wherein the compound having the structure represented by the general formula (1) has a molecular weight of 500 to 1,000.
[4] a substrate;
A pair of electrodes disposed on the substrate, including an anode and a cathode;
An organic layer disposed between the electrodes,
An organic electroluminescence device, wherein the organic layer contains a phosphorescent material and the charge transport material according to any one of [1] to [3].
[5] The organic layer has a light emitting layer containing the phosphorescent material, and the light emitting layer contains a compound having a structure represented by the general formula (1). Organic electroluminescent element.
[6] The light emitting layer includes a partial structure represented by the partial structure represented by the following general formula (3-A) as the compound having the structure represented by the general formula (1). The organic electroluminescent element as described in [5].

(In the general formula (3-A), R ²³⁰ and R ²³¹ are each independently substituted with a hydrogen atom or an aryl group (however, an alkyl group, a halogen atom, a cyano group, or an aryl group may be substituted. And at least one of R ²³⁰ and R ²³¹ represents an aryl group, and one or two of R ²¹¹ to R ²¹⁸ represent a cyano group, provided that not to have each a cyano group three consecutive benzene rings, among .R ²¹¹ ~ R ²¹⁸ does not benzene ring is substituted with three or more benzene rings having cyano group, a cyano group In the case of two, there is no two cyano groups in one benzene ring.)
[7] The light emitting layer contains a compound having a partial structure represented by the following partial structure group (1A) as a compound having a structure represented by the general formula (1) [5] Or the organic electroluminescent element as described in [6].

[8] The organic layer has a light emitting layer containing the phosphorescent material and another organic layer,
Any one of [5] to [7], wherein the other organic layer disposed between the light emitting layer and the cathode contains a compound having a structure represented by the general formula (1). The organic electroluminescent element according to one item.
[9] The partial structure represented by the following partial structure group (1A) as the compound having the structure represented by the general formula (1) as the other organic layer disposed between the light emitting layer and the cathode The organic electroluminescent element as described in [8], comprising a compound having

[10] The compound having a partial structure represented by the partial structure group (1A) is a chain structure in which three or more benzene rings are not substituted on one benzene ring [9] The organic electroluminescent element of description.
[11] The compound having the structure represented by the general formula (1) is represented by any one of the partial structure groups (1A-1), (1A-2), (1A-3), and (1A-7). The organic electroluminescent element as described in [9] or [10], comprising a compound having a partial structure.
[12] The light emitting layer contains at least one compound represented by the general formula (1), and
[11] The organic electroluminescent device as described in [11], wherein the other organic layer disposed between the light emitting layer and the cathode contains at least one compound represented by the general formula (1).
[13] The organic electroluminescent element as described in any one of [8] to [12], wherein an iridium (Ir) complex is used as the phosphorescent material in the light emitting layer.
[14] In any one of [8] to [12], an iridium (Ir) complex represented by the following general formula (E-1) is used for the phosphorescent material as the phosphorescent material. The organic electroluminescent element as described.
Formula (E-1)

In general formula (E-1), Z ¹ and Z ² each independently represents a carbon atom or a nitrogen atom. A ₁ represents an atomic group that forms a 5- or 6-membered heterocycle with Z ¹ and a nitrogen atom. B ₁ represents an atomic group that forms a 5- or 6-membered ring with Z ² and a carbon atom. Z ¹ and Z ² each independently represents a carbon atom or a nitrogen atom. (XY) represents a monoanionic bidentate ligand. n _E1 represents an integer of 1 to 3.
[15] A light-emitting device, a display device, or a lighting device comprising the organic electroluminescent element according to any one of [8] to [14].

According to the present invention, it is possible to provide a charge transport material having a low driving voltage and good durability.

It is the schematic which shows an example of a structure of the organic electroluminescent element which concerns on this invention. It is the schematic which shows an example of the light-emitting device which concerns on this invention. It is the schematic which shows an example of the illuminating device which concerns on this invention. ¹ is a ¹ H-NMR spectrum diagram of a compound 2-11 of the present invention. FIG. ^{1 is} a ¹ H-NMR spectrum of a compound (7-13) of the present invention.

Hereinafter, the contents of the present invention will be described in detail. The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

[Charge transport material]
The charge transport material of the present invention has a structure represented by the following general formula (1), and has 6 to 19 monocyclic aromatic rings (the aromatic ring is a carbon atom or a nitrogen atom) , Having a ring member of 6) (hereinafter, also referred to as a compound represented by the general formula (1)).
General formula (1)

Although the charge transport material of the present invention has such a structure, it is not bound by any theory, but by introducing an electron withdrawing group, the electron affinity is increased and a low driving voltage of the device can be achieved. Estimated. Further, by having such a configuration, the durability of the element is improved, although it is not limited to any theory. Therefore, the organic electroluminescent element using the charge transport material of the present invention is excellent in driving voltage and durability.

The charge transport material represented by the general formula (1) can be preferably used for organic electronic elements such as electrophotography, organic transistors, organic photoelectric conversion elements (for energy conversion, sensor applications, etc.), and organic electroluminescence elements. The organic electroluminescence device is particularly preferably used.
The charge transport material of the present invention can also be used for a thin film containing the compound represented by the general formula (1). The thin film can be formed using the composition by a dry film forming method such as a vapor deposition method or a sputtering method, or a wet film forming method such as a transfer method or a printing method. The thickness of the thin film may be any thickness depending on the application, but is preferably 0.1 nm to 1 mm, more preferably 0.5 nm to 1 μm, still more preferably 1 nm to 200 nm, and particularly preferably 1 nm to 100 nm. is there.

Hereinafter, the preferable range of the charge transport material comprising the compound represented by the general formula (1) will be described.
In the present invention, the hydrogen atom in the description of the general formula (1) includes an isotope (deuterium atom and the like), and the atoms constituting the substituent further include the isotope.
In the present invention, when referred to as “substituent”, the substituent may be substituted. For example, the term “alkyl group” in the present invention includes an alkyl group substituted with a fluorine atom (for example, trifluoromethyl group) and an alkyl group substituted with an aryl group (for example, triphenylmethyl group). When the term “alkyl group having 1 to 6 carbon atoms” is used, it means that all groups including substituted ones have 1 to 6 carbon atoms.

The charge transport material of the present invention relates to a structure represented by the general formula (1).

(In the general formula (1), R ¹¹¹ to R ¹²⁸ represent a hydrogen atom or a substituent. At least one of R ¹¹¹ to R ¹²² is a cyano group.)

Examples of the substituent include a cyano group, an alkyl group having 1 to 10 carbon atoms, a halogen atom, and an aryl group having 6 to 30 carbon atoms.
As the alkyl group, a methyl group, an ethyl group, an isopropyl group, an n-propyl group, a t-butyl group, a s-butyl group, and an n-butyl group are preferable, and a methyl group, an ethyl group, an isopropyl group, and a t-butyl group are preferable. More preferred are a methyl group and a t-butyl group, and a methyl group is particularly preferred.
As the halogen atom, a fluorine atom is preferable.
The aryl group having 6 to 30 carbon atoms is preferably an aryl group that is unsubstituted or substituted with a cyano group, and as a further condition, a chain aryl group (one benzene ring is substituted with 3 or more benzene rings). More preferred).
The substituent is preferably a cyano group, an alkyl group or an aryl group, more preferably a cyano group or an aryl group.

In the case where the compound represented by the general formula (1) is further used in an organic layer of an organic electroluminescent element, a more preferable structure varies depending on which functional layer of the organic layer is used. A more preferable structure of the compound represented by the general formula (1) will be described later in the description of the organic electroluminescence device of the present invention.

The T ₁ energy in the film state of the compound represented by the general formula (1) is preferably 56 kcal / mol or more and 80 kcal / mol or less, more preferably 57 kcal / mol or more and 70 kcal / mol or less, More preferably, it is 58 kcal / mol or more and 66 kcal / mol or less. In particular, when a phosphorescent light emitting material is used as the light emitting material, the T ₁ energy is preferably in the above range.

The T ₁ energy can be determined from the short wavelength end of a phosphorescence emission spectrum of a thin film of material. For example, a material is deposited on a cleaned quartz glass substrate to a thickness of about 50 nm by vacuum deposition, and the phosphorescence emission spectrum of the thin film is measured at F-7000 Hitachi Spectrofluorimeter (Hitachi High Technologies) under liquid nitrogen temperature. Use to measure. T ₁ energy can be obtained by converting the rising wavelength on the short wavelength side of the obtained emission spectrum into energy units.

In the charge transport material of the present invention, the molecular weight of the compound represented by the general formula (1) is preferably 1000 or less, more preferably 500 to 1000, and particularly preferably 600 to 900. . By setting the molecular weight within this range, a material having good film quality and excellent sublimation purification / deposition suitability can be obtained. In particular, the molecular weight of the compound represented by the general formula (1) is preferably 600 to 1000 from the viewpoint of deposition suitability.

The glass transition temperature (Tg) of the compound represented by the general formula (1) is 80 ° C. or higher and 400 ° C. or lower (from the viewpoint of stably operating the organic electroluminescence device against heat generated during high temperature driving or driving the device) Or not detected), more preferably 100 ° C. or higher and 400 ° C. or lower (or not detected), and even more preferably 110 ° C. or higher and 400 ° C. or lower (or not detected).

When the purity of the compound represented by the general formula (1) is low, impurities work as charge transport traps or promote the deterioration of the device. Therefore, the purity of the compound represented by the general formula (1) is high. The more preferable. The purity can be measured by, for example, high performance liquid chromatography (HPLC), and the area ratio of the compound represented by the general formula (1) when detected with a light absorption intensity of 254 nm is preferably 99.00% or more, and more It is preferably 99.50% or more, particularly preferably 99.90% or more, and most preferably 99.9% or more.

As known for the carbazole-based material described in WO2008 / 117889, a material in which part or all of the hydrogen atoms of the compound represented by the general formula (1) are substituted with deuterium atoms is also preferably charged. It can be used as a transport material.

Specific examples of the compound represented by the general formula (1) are shown below, but the present invention is not limited thereto. However, the compound represented by the general formula (1) may belong to two or more of the following general formulas (1A-1) to (1A-20).

The compound represented by the general formula (1) can be synthesized by combining the method described in JP-A-2007-266598 and other known reactions.
After synthesis, it is preferable to purify by sublimation purification after purification by column chromatography, recrystallization or the like. By sublimation purification, not only can organic impurities be separated, but inorganic salts and residual solvents can be effectively removed.

[Organic electroluminescence device]
The organic electroluminescent element of the present invention has a substrate, a pair of electrodes including an anode and a cathode disposed on the substrate, and an organic layer disposed between the electrodes, and the organic layer emits phosphorescence. It contains the material and the charge transport material of the present invention, that is, the compound represented by the general formula (1).

(In the general formula (1), R ¹¹¹ to R ¹²⁸ each represent a hydrogen atom or a substituent. At least one of R ¹¹¹ to R ¹²² is a cyano group, provided that each of the three consecutive benzene rings has a cyano group. The benzene ring having a cyano group is not substituted with three or more benzene rings.

The structure of the organic electroluminescent element of the present invention is not particularly limited. In FIG. 1, an example of a structure of the organic electroluminescent element of this invention is shown. 1 has an organic layer on a substrate 2 between a pair of electrodes (anode 3 and cathode 9).
The element configuration, the substrate, the cathode, and the anode of the organic electroluminescence element are described in detail in, for example, Japanese Patent Application Laid-Open No. 2008-270736, and the matters described in the publication can be applied to the present invention.
Hereinafter, the preferable aspect of the organic electroluminescent element of this invention is demonstrated in detail in order of a board | substrate, an electrode, an organic layer, a protective layer, a sealing container, a drive method, an emission peak wavelength, and a use.

<Board>
The organic electroluminescent element of the present invention has a substrate.
The substrate used in the present invention is preferably a substrate that does not scatter or attenuate light emitted from the organic layer. In the case of an organic material, it is preferable that it is excellent in heat resistance, dimensional stability, solvent resistance, electrical insulation, and workability.

<Electrode>
The organic electroluminescent element of the present invention is disposed on the substrate and has a pair of electrodes including an anode and a cathode.
In view of the properties of the light-emitting element, at least one of the pair of electrodes, the anode and the cathode, is preferably transparent or translucent.

(anode)
The anode usually only needs to have a function as an electrode for supplying holes to the organic layer, and there is no particular limitation on the shape, structure, size, etc., depending on the use and purpose of the light-emitting element, It can select suitably from well-known electrode materials. As described above, the anode is usually provided as a transparent anode.

(cathode)
The cathode usually has a function as an electrode for injecting electrons into the organic layer, and there is no particular limitation on the shape, structure, size, etc., and it is known depending on the use and purpose of the light-emitting element. The electrode material can be selected as appropriate.

<Organic layer>
The organic electroluminescent element of the present invention has an organic layer disposed between the electrodes, and the organic layer includes a phosphorescent material and a compound represented by the general formula (1).
There is no restriction | limiting in particular in the said organic layer, Although it can select suitably according to the use and objective of an organic electroluminescent element, It is preferable to form on the said transparent electrode or the said semi-transparent electrode. In this case, the organic layer is formed on the entire surface or one surface of the transparent electrode or the semitransparent electrode.
There is no restriction | limiting in particular about the shape of a organic layer, a magnitude | size, thickness, etc., According to the objective, it can select suitably.
Hereinafter, in the organic electroluminescent element of the present invention, the configuration of the organic layer, the method for forming the organic layer, preferred embodiments of the layers constituting the organic layer, and materials used for the layers will be described in order.

(Organic layer structure)
In the organic electroluminescent element of the present invention, the organic layer preferably includes a charge transport layer.
The charge transport layer is a layer in which charge transfer occurs when a voltage is applied to the organic electroluminescent element.
Specific examples include a hole injection layer, a hole transport layer, an electron block layer, a light emitting layer, a hole block layer, an electron transport layer, and an electron injection layer. A hole injection layer, a hole transport layer, an electron blocking layer, or a light emitting layer is preferable. If the charge transport layer formed by the coating method is a hole injection layer, a hole transport layer, an electron blocking layer, or a light emitting layer, it is possible to manufacture an organic electroluminescent element with low cost and high efficiency. The charge transport layer is more preferably a hole injection layer, a hole transport layer, or an electron block layer.
The organic electroluminescent element of the present invention preferably has a light emitting layer containing the phosphorescent material and another organic layer, and the light emitting layer contains the compound represented by the general formula (1). Furthermore, in the organic electroluminescent element of the present invention, it is more preferable that the organic layer has a light emitting layer containing the phosphorescent material and another organic layer. However, in the organic electroluminescent element of the present invention, even when the organic layer has a light emitting layer and other organic layers, the layers do not necessarily have to be clearly distinguished.

In the organic electroluminescent element of the present invention, the organic layer contains a phosphorescent material and a compound represented by the general formula (1). At this time, there is no particular limitation on the place where the phosphorescent material and the compound represented by the general formula (1) are included. In this invention, it is more preferable that the said organic layer has the light emitting layer containing the said phosphorescence-emitting material, and another organic layer, and the said light emitting layer contains the compound represented by the said General formula (1). At this time, it is preferable that the compound represented by the general formula (1) is used as a host material of the light emitting layer (hereinafter also referred to as a host compound).

In the present invention, the compound represented by the general formula (1) is not limited in its application, and may be contained in any layer in the organic layer between the cathode and the anode of the organic electroluminescence device. . The introduction layer of the compound represented by the general formula (1) is preferably contained in one or more of the light emitting layer, the layer between the light emitting layer and the cathode, and the layer between the light emitting layer and the anode. , Light-emitting layer, hole injection layer, hole transport layer, electron transport layer, electron injection layer, exciton block layer, charge block layer (hole block layer, electron block layer, etc.) More preferably, it is contained in any one of the light emitting layer, exciton blocking layer, charge blocking layer, electron transporting layer, and electron injection layer, and contained in either the light emitting layer or the hole blocking layer. More particularly preferred.
In the present invention, the compound represented by the general formula (1) is added to the light emitting layer, the organic layer adjacent to the light emitting layer between the light emitting layer and the cathode (the cathode side layer adjacent to the light emitting layer), and the light emitting layer side. It is preferably contained in any of the electron injection layers adjacent to the cathode, more preferably contained in any of the light emitting layer and the cathode side layer adjacent to the light emitting layer, and contained in the light emitting layer. Further preferred. Further, the compound represented by the general formula (1) may be contained in both the light emitting layer and the cathode side layer adjacent to the light emitting layer.

<< When the compound represented by the general formula (1) is contained in the light emitting layer as a host material of the light emitting layer >>
When the compound represented by the general formula (1) is contained in the light emitting layer as a host material of the light emitting layer, the compound represented by the general formula (1) is 0.1 to 99 mass with respect to the total mass of the light emitting layer. %, Preferably 1 to 97% by mass, more preferably 10 to 96% by mass.

When the compound represented by the general formula (1) is used as the host material of the light emitting layer, the LUMO level is preferably in the range of −1.90 eV or more and less than −1.20 eV from the viewpoint of lowering the voltage and light emission efficiency. More preferably, the range is from −1.80 eV to less than −1.30 eV, and even more preferably from −1.70 eV to less than −1.40 eV. This is because the electron injection property from the electron transport layer to the light emitting layer is improved and the driving voltage is lowered.
The specific LUMO level (lowest orbital energy) of the compound represented by the general formula (1) described in this specification is B3LYP / 6-31G (d) // B3LYP / 6-31G (d ) Is the value obtained by performing quantum chemical calculations at the level.
Even with the same electron-withdrawing group, the degree of increasing the LUMO level varies depending on the substitution position. As the tendency, R ¹¹¹ and R ¹¹⁸ in the general formula (2) have the largest influence, followed by R ¹¹⁴ , R ¹¹⁵ , R ¹²¹ , R ¹²² , then R ¹¹³ , R ¹¹⁶ and R ¹²⁰ , and then R ¹¹⁷ and R ¹¹⁹ and then R ¹¹² , and R ¹²³ and R ¹²⁴ to R ¹²⁸ have the least influence, but they are not always in this order.
In this case, the LUMO level described above includes that the light emitting layer includes a partial structure represented by the following general formula (1A) as a compound having the structure represented by the general formula (1) as a host material of the light emitting layer. It is more preferable from the viewpoint of realizing a range of -1.90 eV or more and less than -1.20 eV.

First, an embodiment in which the compound having the structure represented by the general formula (1) is a partial structure represented by the general formula (1A) will be described.

On the other hand, among the partial structures represented by the general formula (1), partial structures represented by the following general formulas (1A-1) to (1A-20), which are more preferable partial structures, are shown below. The invention is not limited to the following specific examples. As the LUMO level of the representative partial structure of the specific examples below, the partial structure represented by the following general formula (1A-1) is −1.51 eV, and the following general formula (1A-2), The partial structure represented by (1A-3) is -1.58 eV, the partial structure represented by the following general formula (1A-5) is -1.56 eV, and the following general formula (1A-6) The partial structure represented is −1.54 eV, and the partial structure represented by the following general formula (1A-7) is −1.76 eV.
The partial structure represented by the following general formula (1A-11) is −1.87 eV, the partial structure represented by the following general formula (1A-12) is −1.85 eV, and the following general formula (1A- The partial structure represented by 13) is -1.73 eV, the partial structure represented by the following general formula (1A-14) is -1.75 eV, and is represented by the following general formula (1A-17) The partial structure is -1.91 eV, the partial structure represented by the following general formula (1A-18) is -1.79 eV, and the partial structure represented by the following general formula (1A-19) is -1. The partial structure represented by the following general formula (1A-20) is -2.01 eV.

When the compound represented by the general formula (1) is used as the host material of the light emitting layer, the maximum light emission wavelength (hereinafter also referred to as emission peak wavelength) of the light emitting material is preferably 400 to 700 nm, and 470 to 650 nm. Is more preferably 490 to 620 nm, and most preferably 500 to 610 nm.

<< When the compound represented by General formula (1) is contained in layers other than a light emitting layer >>
The organic layer includes a light emitting layer containing the phosphorescent material and another organic layer, and the other organic layer disposed between the light emitting layer and the cathode is represented by the general formula (1). It is also preferable to contain a compound having a structure. Among them, the organic layer has an electron transport layer or a hole blocking layer (more preferably, a hole blocking layer), and the electron transport layer or the hole blocking layer is represented by the general formula (1). It is more preferable to contain. When the compound represented by the general formula (1) is contained in a layer other than the light emitting layer, it is preferably contained in an amount of 70 to 100% by mass, based on the total mass of the layer other than the light emitting layer, and 80 to 100% by mass. % Is more preferable.

When the compound of the present invention is used in the electron transport layer, from the viewpoint of lowering the voltage, the LUMO level is preferably in the range of −2.10 eV or more and less than −1.50 eV, preferably −2.00 eV or more and less than −1.55 eV. Is more preferable, and a range of −1.90 eV or more and less than −1.60 eV is even more preferable. This is because the electron injecting property from the cathode to the electron transporting layer is improved and the electron injecting property to the light emitting layer is improved.
In this case, the other organic layer disposed between the light emitting layer and the cathode includes a partial structure represented by the general formula (1A) as a compound having a structure represented by the general formula (1). Is preferable from the viewpoint of realizing the above-mentioned LUMO level of −2.10 eV or more and less than −1.50 eV.

Among the partial structures represented by the general formula (4-A), in the present invention, another organic layer disposed between the light emitting layer and the cathode is represented by the general formula (1). Although it is more preferable to contain a compound having a partial structure represented by the following partial structure group A ′ as a structural compound, the present invention is not limited to the following specific examples.

On the other hand, in this invention, the other organic layer arrange | positioned between the said light emitting layer and the said cathode is represented by the said partial structure group (1A) as a compound of the structure represented by the said General formula (1). It is also preferable to contain a compound having a partial structure.

These organic layers may be provided in a plurality of layers, and when a plurality of layers are provided, they may be formed of the same material or different materials for each layer.

(Formation method of organic layer)
In the organic electroluminescence device of the present invention, each organic layer is formed by a dry film forming method such as a vapor deposition method or a sputtering method, a wet film forming method such as a transfer method, a printing method, a spin coating method, or a bar coating method (solution coating method). Any of these can be suitably formed.
In the organic electroluminescent element of the present invention, the organic layer disposed between the pair of electrodes includes at least one layer formed by vapor deposition of a composition containing the compound represented by the general formula (1). Is preferred.

(Light emitting layer)
The light emitting layer receives holes from the anode, hole injection layer or hole transport layer and receives electrons from the cathode, electron injection layer or electron transport layer when an electric field is applied, and provides a field for recombination of holes and electrons. And a layer having a function of emitting light. However, the light emitting layer in the present invention is not necessarily limited to light emission by such a mechanism. The light emitting layer in the organic electroluminescent element of the present invention preferably contains at least one phosphorescent material.

The light emitting layer in the organic electroluminescent device of the present invention may be composed only of the light emitting material, or may be a mixed layer of a host material and the light emitting material. The kind of the light emitting material may be one kind or two kinds or more. The host material is preferably a charge transport material. The host material may be one kind or two or more kinds, and examples thereof include a configuration in which an electron transporting host material and a hole transporting host material are mixed. Furthermore, the light emitting layer may include a material that does not have charge transporting properties and does not emit light.

Further, the light emitting layer may be a single layer or a multilayer of two or more layers, and each layer may contain the same light emitting material or host material, or each layer may contain a different material. When there are a plurality of light emitting layers, each of the light emitting layers may emit light with different emission colors.

The thickness of the light emitting layer is not particularly limited, but is usually preferably 2 nm to 500 nm, and more preferably 3 nm to 200 nm, and more preferably 5 nm to 100 nm from the viewpoint of external quantum efficiency. More preferably.

In the organic electroluminescent element of the present invention, it is preferable that the light emitting layer contains a compound represented by the general formula (1), and the host material of the light emitting layer is represented by the general formula (1). It is a more preferable embodiment to use a compound. Here, in this specification, the host material is a compound mainly responsible for charge injection and transport in the light emitting layer, and is a compound that itself does not substantially emit light. Here, “substantially does not emit light” means that the amount of light emitted from the compound that does not substantially emit light is preferably 5% or less, more preferably 3% or less of the total amount of light emitted from the entire device. Preferably it says 1% or less.
Hereinafter, as the material of the light emitting layer, the host material other than the light emitting material and the compound represented by the general formula (1) will be described in order. In addition, the compound represented by the said General formula (1) may be used other than the said light emitting layer in the organic electroluminescent element of this invention.

(Luminescent material)
As the light emitting material in the present invention, any of phosphorescent light emitting materials, fluorescent light emitting materials and the like can be used.
The light emitting layer in the present invention can contain two or more kinds of light emitting materials in order to improve the color purity and broaden the light emission wavelength region. At least one of the light emitting materials is preferably a phosphorescent light emitting material.
In the present invention, in addition to at least one phosphorescent light-emitting material contained in the light-emitting layer, a fluorescent light-emitting material or a phosphorescent light-emitting material different from the phosphorescent light-emitting material contained in the light-emitting layer can be used as the light-emitting material.
Details of these fluorescent materials and phosphorescent materials are described in, for example, paragraph numbers [0100] to [0164] of JP-A-2008-270736 and paragraph numbers [0088] to [0090] of JP-A-2007-266458. The matters described in these publications can be applied to the present invention.

Examples of phosphorescent light-emitting materials that can be used in the present invention include US Pat. / 19373A2, JP-A No. 2001-247859, JP-A No. 2002-302671, JP-A No. 2002-117978, JP-A No. 2003-133074, JP-A No. 2002-1235076, JP-A No. 2003-123684, JP-A No. 2002-170684, EP No. 121157, JP-A No. 2002 -226495, JP 2002-234894, JP 2001-247859, JP 2001-298470, JP 2002-1736 4, JP2002-203678, JP2002-203679, JP2004-357679, JP2006-256999, JP2007-19462, JP2007-84635, JP2007-96259, WO07 / 095118, WO10 / 111175, WO10 / 027583, WO10 / 028151, and the like, and phosphorescent compounds described in patent documents such as WO10 / 028151 are mentioned. Among them, more preferable luminescent materials include iridium (Ir) complexes, platinum (Pt) complexes, Cu complexes, and Re complexes. , W complexes, Rh complexes, Ru complexes, Pd complexes, Os complexes, Eu complexes, Tb complexes, Gd complexes, Dy complexes, and Ce complexes. Particularly preferred is an iridium (Ir) complex, a platinum (Pt) complex, or a Re complex. Among them, at least one coordination mode of a metal-carbon bond, a metal-nitrogen bond, a metal-oxygen bond, or a metal-sulfur bond is used. An iridium (Ir) complex, a platinum (Pt) complex, or a Re complex is preferable. Furthermore, iridium (Ir) complex and platinum (Pt) complex are particularly preferable, and iridium (Ir) complex is most preferable from the viewpoint of luminous efficiency, driving durability, chromaticity and the like.

As the phosphorescent material contained in the light emitting layer in the present invention, it is preferable to use an iridium (Ir) complex represented by the following general formula (E-1) or the following platinum (Pt) complex.

The general formula (E-1) will be described.

In general formula (E-1), Z ¹ and Z ² each independently represents a carbon atom or a nitrogen atom. A ₁ represents an atomic group that forms a 5- or 6-membered heterocycle with Z ¹ and a nitrogen atom. B ₁ represents an atomic group that forms a 5- or 6-membered ring with Z ² and a carbon atom. Z ¹ and Z ² each independently represents a carbon atom or a nitrogen atom. (XY) represents a monoanionic bidentate ligand. n _E1 represents an integer of 1 to 3.

Z ¹ and Z ² are preferably carbon atoms. n _E1 is preferably 2 or 3, in which case there are two or three ligands containing Z ¹ , Z ² , A ₁ , B _1, which are the same as each other May be different.

Examples of the 5- or 6-membered heterocycle containing A ₁ , Z ¹ and a nitrogen atom include a pyridine ring, pyrimidine ring, pyrazine ring, triazine ring, imidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole Ring, thiadiazole ring and the like. The 5- or 6-membered heterocycle formed by A ₁ , Z ¹ and a nitrogen atom may have a substituent.

Examples of the 5- or 6-membered ring formed by B ₁ , Z ² and a carbon atom include a benzene ring, a pyridine ring, a pyrimidine ring, a pyrazine ring, a pyridazine ring, a triazine ring, an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring, Examples include a triazole ring, an oxadiazole ring, a thiadiazole ring, a thiophene ring, a furan ring, and a pyrrole ring. The 5- or 6-membered ring formed by B ₁ , Z ² and a carbon atom may have a substituent.

The following substituent group A is mentioned as said substituent. The substituents may be linked to form a ring. Examples of the ring formed include an unsaturated 4- to 7-membered ring, a benzene ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, an imidazole ring, Examples thereof include an oxazole ring, a thiazole ring, a pyrazole ring, a thiophene ring, and a furan ring. These formed rings may have a substituent, and may further form a ring via a substituent on the formed ring. Further, a 5- or 6-membered heterocyclic substituent formed by A ₁ , Z ¹ and a nitrogen atom, and a 5- or 6-membered ring substituent formed by B ₁ , Z ² and a carbon atom, They may be linked to form a condensed ring similar to that described above. A ring may be further formed through a substituent on the formed ring.

<< Substituent group A >>
An alkyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms, such as methyl, ethyl, isopropyl, t-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), alkenyl groups (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as vinyl , Allyl, 2-butenyl, 3-pentenyl, etc.), alkynyl group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms such as propargyl , 3-pentynyl, etc.), aryl groups (preferably having 6 to 30 carbon atoms, more preferably 6 to 0, particularly preferably 6 to 12 carbon atoms, such as phenyl, p-methylphenyl, naphthyl, anthranyl, etc.), amino group (preferably 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms). Particularly preferably 0 to 10 carbon atoms, such as amino, methylamino, dimethylamino, diethylamino, dibenzylamino, diphenylamino, ditolylamino, etc.), an alkoxy group (preferably having 1 to 30 carbon atoms, Preferably it has 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms, and examples thereof include methoxy, ethoxy, butoxy, 2-ethylhexyloxy, etc.), an aryloxy group (preferably having 6 to 30 carbon atoms, More preferably, it has 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms. And a heterocyclic oxy group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms). For example, pyridyloxy, pyrazyloxy, pyrimidyloxy, quinolyloxy, etc.), an acyl group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 2 to 12 carbon atoms). , Benzoyl, formyl, pivaloyl, etc.), an alkoxycarbonyl group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 12 carbon atoms such as methoxycarbonyl, ethoxy Carbonyl, etc.), an aryloxycarbonyl group (preferably having a carbon number) The number of carbon atoms is 7 to 30, more preferably 7 to 20, and particularly preferably 7 to 12, and examples thereof include phenyloxycarbonyl. ), An acyloxy group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as acetoxy, benzoyloxy, etc.), an acylamino group (preferably 2-30 carbon atoms, more preferably 2-20 carbon atoms, particularly preferably 2-10 carbon atoms, and examples thereof include acetylamino, benzoylamino and the like, and alkoxycarbonylamino groups (preferably having 2-2 carbon atoms). 30, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonylamino, etc.), an aryloxycarbonylamino group (preferably having 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, particularly preferably 7 to 12 carbon atoms, for example phenyloxycarbonyl And sulfonylamino groups (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfonylamino and benzenesulfonylamino). ), A sulfamoyl group (preferably having 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms, particularly preferably 0 to 12 carbon atoms, such as sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenyl Sulfamoyl, etc.), carbamoyl groups (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as carbamoyl, methylcarbamoyl, diethylcarbamoyl, Phenylcarbamoyl etc.), alkylthio group ( Preferably, it has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio, ethylthio, etc.), an arylthio group (preferably 6 to 30 carbon atoms). More preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio, etc.), a heterocyclic thio group (preferably 1 to 30 carbon atoms, more preferably 1 to carbon atoms). 20, particularly preferably 1 to 12 carbon atoms, such as pyridylthio, 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio and the like, and a sulfonyl group (preferably having a carbon number of 1 to 30, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include mesyl and tosyl). Rufinyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include methanesulfinyl and benzenesulfinyl. ), A ureido group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as ureido, methylureido, phenylureido, etc.), phosphoric acid An amide group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as diethyl phosphoric acid amide and phenyl phosphoric acid amide), a hydroxy group , Mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group ( An aromatic heterocyclic group is also included, preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms. Is, for example, a nitrogen atom, oxygen atom, sulfur atom, phosphorus atom, silicon atom, selenium atom, tellurium atom, specifically pyridyl, pyrazinyl, pyrimidyl, pyridazinyl, pyrrolyl, pyrazolyl, triazolyl, imidazolyl, oxazolyl, thiazolyl, And isoxazolyl, isothiazolyl, quinolyl, furyl, thienyl, selenophenyl, tellurophenyl, piperidyl, piperidino, morpholino, pyrrolidyl, pyrrolidino, benzoxazolyl, benzoimidazolyl, benzothiazolyl, carbazolyl group, azepinyl group, silolyl group and the like. A silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably 3 to 24 carbon atoms, and examples thereof include trimethylsilyl and triphenylsilyl). A aryloxy group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably 3 to 24 carbon atoms, such as trimethylsilyloxy, triphenylsilyloxy, etc.), phosphoryl group (for example, A diphenylphosphoryl group, a dimethylphosphoryl group, etc.). These substituents may be further substituted, and examples of the further substituent include a group selected from the substituent group A described above. Moreover, the substituent substituted by the substituent may be further substituted, and examples of the further substituent include a group selected from the substituent group A described above. Moreover, the substituent substituted by the substituent substituted by the substituent may be further substituted, and examples of the further substituent include a group selected from the substituent group A described above.

As the ligand represented by (XY), there are various known ligands used in conventionally known metal complexes. For example, “Photochemistry and Photophysics of Coordination Compounds” Springer-Verlag H. Yersin, published in 1987, mention may be made of nitrogen-containing heteroaryl ligands, diketone ligands, etc., and the following general formulas (l-1) to (l-39) are preferred, and general formulas (l-1), (l -4), (1-15), (1-16), (1-17), (1-18), (1-19), (1-22), (1-25), (1-28) ), (L-29), (l-36), and (l-39) are more preferred. However, the present invention is not limited to these.

* Represents a coordination position to iridium (Ir) in the general formula (E-1). Rx, Ry and Rz each independently represents a hydrogen atom or a substituent. Examples of the substituent include a substituent selected from the substituent group A. Rx and Rz are preferably each independently an alkyl group, a perfluoroalkyl group, or an aryl group. Ry is preferably any one of a hydrogen atom, an alkyl group, a perfluoroalkyl group, a fluorine atom, a cyano group, and an aryl group. A plurality of Rx and Ry existing in one ligand may be the same or different.
Ry may be bonded to each other to form a ring. Rx are not bonded to each other.

Complexes having these ligands can be synthesized in the same manner as in known synthesis examples by using corresponding ligand precursors.

A preferred embodiment of the iridium (Ir) complex represented by the general formula (E-1) is an iridium (Ir) complex represented by the following general formula (E-2).

Formula (E-2)

In general formula (E-2), A ^E1 to A ^E8 each independently represents a nitrogen atom or C—R ^E. R ^E represents a hydrogen atom or a substituent. As the substituent, those exemplified as the substituent group A can be applied. R ^E may be connected to each other to form a ring. Examples of the ring formed include the same ring as the condensed ring described in the general formula (E-1). (X-Y) and n _E2 is (X-Y) in Formula (E1) have the same meanings as and n _E1, preferred ranges are also the same. When n _E2 is 2 or 3, there are two or three ligands containing A ^E1 to A ^E8, and these ligands may be the same or different.

A more preferred form of the compound represented by the general formula (E-2) is a compound represented by the following general formula (E-3).

In the general formula (E-3), R ^T1 , R ^T2 , R ^T3 , R ^T4 , R ^T5 , R ^T6, and R ^T7 have the same meaning as R ^E. A represents CR ″ ″ or a nitrogen atom, and R ″ ″ has the same ^meaning as RE. R ^T1 to R ^T7 and R ″ ″ may be bonded to any two adjacent to each other to form a condensed 4- to 7-membered ring. A fused 4- to 7-membered ring may further have a substituent represented by the substituent group A. (XY) and n _E3 have the same _{meanings as} (XY) and n _E1 in formula (E-1), and the preferred ranges are also the same. When n _E3 is 2 or 3, there are two or three ligands including R ^T1 , R ^T2 , R ^T3 , R ^T4 , R ^T5 , R ^T6 , R ^T7 and A. The ligands may be the same as or different from each other.

The preferable range of A and R ^T1 to R ^T7 varies depending on the emission color required according to the application. In the following, description will be given by dividing into three regions of blue to light blue, green to yellow, yellow orange to red as target emission colors. However, it is not limited to these descriptions.

In order to obtain a yellow-orange to red emission color, a compound represented by the following general formula (E-4), general formula (E-5) or general formula (E-6) is preferable.

General formula (E-4)

R ^T1 to R ^T4 , R ^T7 , A (CR ″ ″ or a nitrogen atom), (XY) and n _E4 in the general formula (E-4) are R ^T1 to R ^T1 in the general formula (E-3). It is synonymous with R ^T4 , R ^T7 , A, (XY) and n _E3 . R ₁ ′ to R ₄ ′ have the same meaning as R ^E.
R ^T1 to R ^T4 , R ^T7 , R ₁ ′ to R ₄ ′ and R ″ ″ may be bonded to each other to form a condensed 4- to 7-membered ring. The 7-membered ring is cycloalkene, cyclocarbadiene, aryl, or heteroaryl, and the fused 4- to 7-membered ring may further have a substituent represented by Substituent Group A.
When n _E4 is 2 or 3, there are two or three ligands including R ^T1 to R ^T4 , R ^T7 , A and R ₁ ′ to R ₄ ′. They may be the same or different.

R ₁ ′ to R ₄ ′ are preferably a hydrogen atom, a fluorine atom, an alkyl group, or an aryl group. Further, it is preferable that A represents CR ″ ″, and 0 to 3 of R ^T1 to R ^T4 , R ^T7 and R ″ ″ are an alkyl group or a phenyl group, and the rest are all hydrogen atoms.

Preferred specific examples of the compound represented by the general formula (E-4) are listed below, but are not limited thereto.

General formula (E-5)

R ^T2 to R ^T6 , A (CR ″ ″ or nitrogen atom), (XY) and n _E5 in the general formula (E-5) are R ^T2 to R ^T6 in the general formula (E-3), Synonymous with A, (XY) and n _E3 . R ₅ ′ to R ₈ ′ have the same meanings as R ₁ ′ to R ₄ ′ in formula (E-4). R ^T2 to R ^T6 , R ₅ ′ to R ₈ ′, and R ″ ″ may be bonded to each other to form a condensed 4- to 7-membered ring. The ring is a cycloalkene, cyclocarbadiene, aryl or heteroaryl, and the condensed 4- to 7-membered ring may further have a substituent represented by the substituent group A.
When n _E5 is 2 or 3, there are two or three ligands containing R ^T2 to R ^T6 , A and R ₅ ′ to R ₈ ′. It can be different.
The preferred range for R ₅ ′ to R ₈ ′ is the same as the preferred range for R ₁ ′ to R ₄ ′ in formula (E-4). A represents CR ″ ″, and among R ^T2 to R ^T6 , R ″ ″, and R ₅ ′ to R ₈ ′, 0 to 3 are alkyl groups or phenyl groups, and the rest are all hydrogen atoms. Is preferred.

Preferred specific examples of the compound represented by formula (E-5) are listed below, but are not limited thereto.

General formula (E-6)

R ^T1 to R ^T5 , A (CR ″ ″ or nitrogen atom), (XY) and n _E6 in the general formula (E-6) are R ^T1 to R ^T5 in the general formula (E-3), Synonymous with A, (XY) and n _E3 . R ₉ ′ to R ₁₂ ′ have the same meanings as R ₁ ′ to R ₄ ′ in formula (E-4). R ^T1 to R ^T5 , R ₉ ′ to R ₁₂ ′, and R ″ ″ may be bonded to each other to form a condensed 4- to 7-membered ring. The ring is a cycloalkene, cyclocarbadiene, aryl or heteroaryl, and the condensed 4- to 7-membered ring may further have a substituent represented by the substituent group A.
When n _E6 is 2 or 3, there are two or three ligands containing R ^T1 to R ^T5 , A and R ₉ ′ to R ₁₂ ′. It can be different.
The preferred range for R ₉ ′ to R ₁₂ ′ is the same as the preferred range for R ₁ ′ to R ₄ ′ in formula (E-4). A represents CR ″ ″, and among R ^T1 to R ^T5 , R ″ ″, and R ₉ ′ to R ₁₂ ′, 0 to 3 are alkyl groups or phenyl groups, and the rest are all hydrogen atoms. Is preferred.

Preferred specific examples of the compound represented by formula (E-6) are listed below, but are not limited thereto.

In order to obtain a green to yellow emission color, a compound represented by the following general formula (E-7) is preferable.

General formula (E-7)

In the general formula (E-7), R ^T1 , R ^T2 , R ^T3 , R ^T4 , R ^T5 , R ^T6 , R ^T7 , R ″ ″, (XY) and n _E3 are represented by the general formula (E− It is synonymous with R ^T1 , R ^T2 , R ^T3 , R ^T4 , R ^T5 , R ^T6 , R ^T7 , R ″ ″, (XY) and n _{E3 in 3} ). R ^T1 to R ^T7 and R ″ ″ may be bonded to any two adjacent to each other to form a condensed 4- to 7-membered ring. A fused 4- to 7-membered ring may further have a substituent represented by the substituent group A.
When n _E7 is 2 or 3, there are two or three ligands including R ^T1 , R ^T2 , R ^T3 , R ^T4 , R ^T5 , R ^T6 , R ^T7 and R ″ ″. However, the ligands may be the same or different from each other.

R ^T1 , R ^T2 , R ^T3 , R ^T4 , R ^T5 , R ^T6 , R ^T7 , R ″ ″ may be a hydrogen atom, a fluorine atom, an alkyl group, an aryl group, a heteroaryl group, or a cyano group preferable.

n _E7 is preferably 3, and the general formula (E-7) is preferably a compound represented by the general formula (E-7-1).

Formula (E-7-1)

In the general formula (E-7-1), R ^T1 , R ^T2 , R ^T3 , R ^T4 , R ^T5 , R ^T6 , R ^T7 , R ″ ″ are R ^T1 in the general formula (E-7), R ^T2 , R ^T3 , R ^T4 , R ^T5 , R ^T6 , R ^T7 , R ″ ″ have the same meanings and preferred ranges. R ^T8 to R ^T15 are synonymous with R ^T1 , R ^T2 , R ^T3 , R ^T4 , R ^T5 , R ^T6 , R ^T7 , R ″ ″ and the preferred ranges are also the same, but R ^T1 , R ^T2 , A phenylpyridine ligand containing R ^T3 , R ^T4 , R ^T5 , R ^T6 , R ^T7 , R ″ ″ and a phenylpyridine ligand containing R ^T8 to R ^T15 are different from each other.

In order to obtain an emission color close to green among green to yellow emission colors, R ^T1 , R ^T2 , R ^T3 , R ^T4 , R ^T5 , R ^T6 , R ^T7 , R ″ ″ are hydrogen atoms, A fluorine atom, an alkyl group, and a cyano group are more preferable, and 1 to 3 of R ^T1 , R ^T5 , R ^T4 , and R ″ ″ are more preferably an alkyl group. R ^T8 to R ^T11 are more preferably a hydrogen atom or an alkyl group. R ^T12 to R ^T15 are more preferably a hydrogen atom, an alkyl group, a cyano group, or an aryl group. The substitution position of the alkyl group, cyano group or aryl group is preferably R ^T13 or R ^T14 . The aryl group may further have a substituent, and may form a condensed ring through the substituent.

In order to obtain an emission color close to yellow among green to yellow emission colors, R ^T1 , R ^T2 , R ^T3 , R ^T4 , R ^T5 , R ^T6 , R ^T7 , R ″ ″ are hydrogen atoms, It is more preferably an alkyl group, and more preferably 1 to 3 of R ^T1 , R ^T5 , R ^T4 and R ″ ″ are alkyl groups. It is more preferable that at least one of R ^T8 to R ^T11 is an aryl group, and it is more preferable that any one of R ^T9 and R ^T10 is an aryl group and the remaining is a hydrogen atom or an alkyl group. The aryl group may further have a substituent, and may form a condensed ring through the substituent.

The general formula (E-7-1) preferably has a partial structure represented by the general formula (E-7-2) in the general formula (E-7-1). By having the general formula (E-7-2), effects such as low voltage and high durability may be noticeable depending on the combination with the host material.

General formula (E-7-2)

In general formula (E-7-2), X represents —O—, —S—, —NR ^T24 —, —CR ^T25 R ^T26 —, —SiR ^T27 R ^T28 —, and any one of R ^T16 to R ^T28 One is bonded to part of the general formula (E-7-1) through a single bond or a substituent.

In general formula (E-7-2), any one of R ^T16 to R ^T28 is preferably bonded to a part of general formula (E-7-1) via a single bond or an aryl group, When it is desired to obtain a light emission color close to, it is more preferable to bond with R ^T13 or R ^T14 , and further preferable to bond with R ^T13 . When it is desired to obtain a light emission color close to yellow, it is more preferable to bond with R ^T9 or R ^T10 .
X is preferably —O—, —S—, —NR ^T24 —, —CR ^T25 R ^T26 —, and more preferably —O—, —S—.
When X is —O— or —S—, it is preferably bonded to a part of formula (E-7-1) through a single bond at the position of R ^T16 , and X is —NR ^T24 — In this case, it is preferable to bond to a part of the general formula (E-7-1) through a single bond at the position of R ^T18 or R ^T24 , and when X is —CR ^T25 R ^T26 —, R ^T17 It is preferable to bond to a part of the general formula (E-7-1) through a single bond at the position.

Preferred specific examples of the compound represented by formula (E-7) are listed below, but are not limited thereto.

In order to obtain a blue to light blue luminescent color, a compound represented by the following general formula (E-8) or general formula (E-9) is preferable.

General formula (E-8)

In general formula (E-8), R ^T1 , R ^T2 , R ^T3 , R ^T4 , R ^T5 , R ^T6 , R ^T7 , A (CR ″ ″ or nitrogen atom), (XY), n _E8 Is synonymous with R ^T1 , R ^T2 , R ^T3 , R ^T4 , R ^T5 , R ^T6 , R ^T7 , A, (XY), and n _E3 in the general formula (E-3).

In general formula (E-8), R ^T1 and R ^T5 to R ^T7 are more preferably a hydrogen atom, an alkyl group, or an aryl group. R ^T2 to R ^T4 are preferably a hydrogen atom, a fluorine atom, or a cyano group. In A, R ″ ″ of CR ″ ″ is preferably a fluorine atom or a cyano group, or a nitrogen atom. n _E8 is preferably 2 or 3. (XY) has the same meaning as (XY) in formula (E-1), and the preferred range is also the same.

Preferred specific examples of the compound represented by formula (E-8) are listed below, but are not limited thereto.

General formula (E-9)

In the general formula (E-9), R ^T29 to R ^T34 , (XY), and n _E8 have the same _meanings as R ^T1 to R ^T6 (XY) and n _{E3 in the} general formula (E-3). . R ^T35 represents a substituent, and examples of the substituent include the substituent group B. R ^T29 to R ^T35 may combine any two adjacent to each other to form a condensed 4- to 7-membered ring, and the fused 4- to 7-membered ring is a cycloalkene, cyclocarbadiene, aryl or heteroaryl The condensed 4- to 7-membered ring may further have a substituent represented by the substituent group A.
When n _E7 is 2 or 3, there are two or three ligands including R ^T1 , R ^T2 , R ^T3 , R ^T4 , R ^T5 , R ^T6 , R ^T7 and R ″ ″. However, the ligands may be the same or different from each other.

R ^T29 to R ^T34 are preferably a hydrogen atom, an alkyl group, an aryl group, or a cyano group. R ^T35 is preferably an alkyl group or an aryl group. R ^T35 is preferably linked to R ^T29 to form a ring, and R ^T35 and R ^T29 are more preferably bonded via an aryl group, resulting in the formation of a nitrogen-containing 6-membered ring. In R ^{T35, the} aryl group linked to R ^T29 may further have a substituent, and is more preferably substituted with an alkyl group from the viewpoint of durability.

Preferred specific examples of the compound represented by formula (E-9) are listed below, but are not limited thereto.

Preferred specific examples other than the above of the compound represented by the general formula (E-1) are listed below, but are not limited thereto.

The compounds exemplified as the compound represented by the general formula (E-1) can be synthesized by the method described in JP2009-99783A, various methods described in US Pat. No. 7,279,232 and the like. After synthesis, it is preferable to purify by sublimation purification after purification by column chromatography, recrystallization or the like. By sublimation purification, not only can organic impurities be separated, but inorganic salts and residual solvents can be effectively removed.

The compound represented by the general formula (E-1) is preferably contained in the light emitting layer, but its use is not limited, and may be further contained in any layer in the organic layer. .

The compound represented by the general formula (E-1) in the light emitting layer is generally contained in the light emitting layer in an amount of 0.1% by mass to 50% by mass with respect to the total mass of the compound forming the light emitting layer. From the viewpoint of durability and external quantum efficiency, the content is preferably 0.2% by mass to 50% by mass, more preferably 0.3% by mass to 40% by mass, and more preferably 0.4% by mass to 30%. More preferably, it is contained in an amount of 0.5% by mass to 20% by mass.

A compound represented by the general formula (1), a partial structure represented by the general formula (3-A), a partial structure group (1A), and any one of the general formulas (E-1) to (E-9) It is particularly preferable in the present invention to use the compounds represented in combination in the light emitting layer.

Specific examples of the platinum (Pt) complex include compounds described in [0143] to [0152], [0157] to [0158], and [0162] to [0168] of JP-A No. 2005-310733, Compounds described in [0065] to [0083] of 2006-256999, compounds described in [0065] to [0090] of JP-A-2006-93542, and [0063] to [0063] of JP-A-2007-73491 Compounds described in [0071], compounds described in [0079] to [0083] of JP-A-2007-324309, compounds described in [0065] to [0090] of JP-A-2006-93542, JP-A Compounds described in [0055] to [0071] of 2007-96255, [0043] of JP-A-2006-313796 [0046] and the like.

The platinum (Pt) complex that can be used as the phosphorescent material is preferably a platinum (Pt) complex represented by the following general formula (C-1).

(In the formula, Q ¹ , Q ² , Q ³ and Q ⁴ each independently represent a ligand coordinated to platinum (Pt). L ¹ , L ² and L ³ are each independently a single bond or a divalent group. Represents a linking group.)

The general formula (C-1) will be described. Q ¹ , Q ² , Q ³ and Q ⁴ each independently represent a ligand coordinated to platinum (Pt). At this time, the bond between Q ¹ , Q ² , Q ³ and Q ⁴ and platinum (Pt) may be any of a covalent bond, an ionic bond, a coordinate bond, and the like. As an atom couple | bonded with platinum (Pt) in Q < ¹ >, Q < ² >, Q < ³ > and Q < ⁴ >, a carbon atom, a nitrogen atom, an oxygen atom, a sulfur atom, and a phosphorus atom are preferable, Q < ¹ >, Q < ² >, Q < ³ > Of the atoms bonded to platinum (Pt) in Q ⁴ , at least one is preferably a carbon atom, more preferably two are carbon atoms, two are carbon atoms, and two are nitrogen atoms. Is particularly preferred.
Q ¹ , Q ² , Q ^3, and Q ⁴ bonded to platinum (Pt) by a carbon atom may be an anionic ligand or a neutral ligand, and the anionic ligand is a vinyl group. Ligand, aromatic hydrocarbon ring ligand (eg benzene ligand, naphthalene ligand, anthracene ligand, phenanthrene ligand, etc.), heterocyclic ligand (eg furan ligand, thiophene coordination) Pyridine ligand, pyrazine ligand, pyrimidine ligand, pyridazine ligand, triazine ligand, thiazole ligand, oxazole ligand, pyrrole ligand, imidazole ligand, pyrazole coordination Child, a triazole ligand, and a condensed ring containing them (for example, quinoline ligand, benzothiazole ligand, etc.). A carbene ligand is mentioned as a neutral ligand.

The groups represented by Q ¹ , Q ² , Q ³ and Q ⁴ may have a substituent, and as the substituent, those exemplified as the substituent group A can be appropriately applied. Moreover, substituents may be connected to each other (when Q ³ and Q ⁴ are connected, a platinum (Pt) complex of a cyclic tetradentate ligand is formed).

The group represented by Q ¹ , Q ² , Q ³ and Q ⁴ is preferably an aromatic hydrocarbon ring ligand bonded to platinum (Pt) by a carbon atom, and an aromatic bonded to platinum (Pt) by a carbon atom. Heterocyclic heterocyclic ligands, nitrogen-containing aromatic heterocyclic ligands bonded to platinum (Pt) with nitrogen atoms, acyloxy ligands, alkyloxy ligands, aryloxy ligands, heteroaryloxy ligands A silyloxy ligand, more preferably an aromatic hydrocarbon ring ligand bonded to platinum (Pt) at a carbon atom, an aromatic heterocyclic ligand bonded to platinum (Pt) at a carbon atom, nitrogen Nitrogen-containing aromatic heterocyclic ligands, acyloxy ligands, and aryloxy ligands bonded to platinum (Pt) with atoms, more preferably aromatic hydrocarbon rings bonded to platinum (Pt) with carbon atoms Ligand, carbon atom platinum (Pt) An aromatic heterocyclic ligand bonded to the nitrogen atom, a nitrogen-containing aromatic heterocyclic ligand bonded to platinum (Pt) with a nitrogen atom, and an acyloxy ligand.

L ¹ , L ² and L ³ represent a single bond or a divalent linking group. Divalent linking groups represented by L ¹ , L ² and L ³ include alkylene groups (methylene, ethylene, propylene, etc.), arylene groups (phenylene, naphthalenediyl), heteroarylene groups (pyridinediyl, thiophenediyl, etc.) ), Imino group (—NR—) (eg phenylimino group), oxy group (—O—), thio group (—S—), phosphinidene group (—PR—) (eg phenylphosphinidene group), silylene group (—SiRR′—) (dimethylsilylene group, diphenylsilylene group, etc.), or a combination thereof. Here, R and R ′ each independently include an alkyl group, an aryl group, and the like. These linking groups may further have a substituent.
From the viewpoint of stability and emission quantum yield of the complex, preferably a single bond as L ^1, L ² and L ^3, an alkylene group, an arylene group, heteroarylene group, an imino group, an oxy group, a thio group, be a silylene group More preferably a single bond, an alkylene group, an arylene group or an imino group, still more preferably a single bond, an alkylene group or an arylene group, still more preferably a single bond, a methylene group or a phenylene group, still more preferably. Single bond, disubstituted methylene group, more preferably single bond, dimethylmethylene group, diethylmethylene group, diisobutylmethylene group, dibenzylmethylene group, ethylmethylmethylene group, methylpropylmethylene group, isobutylmethylmethylene group, diphenyl Methylene group, methylphenylmethylene group, cyclohexanediyl group, cyclope An tandiyl group, a fluorenediyl group, and a fluoromethylmethylene group.
L ¹ is particularly preferably a dimethylmethylene group, a diphenylmethylene group, or a cyclohexanediyl group, and most preferably a dimethylmethylene group.
L ² and L ³ are most preferably a single bond.

Of the platinum (Pt) complexes represented by the general formula (C-1), a platinum (Pt) complex represented by the following general formula (C-2) is more preferable.

(In the formula, L ²¹ represents a single bond or a divalent linking group. A ²¹ and A ²² each independently represents a carbon atom or a nitrogen atom. Z ²¹ and Z ²² each independently represent a nitrogen-containing aromatic heterocyclic ring. Z ²³ and Z ²⁴ each independently represents a benzene ring or an aromatic heterocycle.

The general formula (C-2) will be described. L ²¹ has the same meaning as L ^{1 in} formula (C-1), and the preferred range is also the same.

A ²¹ and A ²² each independently represent a carbon atom or a nitrogen atom. Of A ^21, A ^22, Preferably, at least one is a carbon atom, it A ^21, A ²² are both carbon atoms are preferred from the standpoint of emission quantum yield stability aspects and complexes of the complex .

Z ²¹ and Z ²² each independently represent a nitrogen-containing aromatic heterocycle. Examples of the nitrogen-containing aromatic heterocycle represented by Z ²¹ and Z ²² include a pyridine ring, pyrimidine ring, pyrazine ring, triazine ring, imidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, Examples include thiadiazole rings. From the viewpoints of complex stability, emission wavelength control and emission quantum yield, the ring represented by Z ²¹ and Z ²² is preferably a pyridine ring, a pyrazine ring, an imidazole ring or a pyrazole ring, more preferably a pyridine ring. , An imidazole ring and a pyrazole ring, more preferably a pyridine ring and a pyrazole ring, and particularly preferably a pyridine ring.

Z ²³ and Z ²⁴ each independently represent a benzene ring or an aromatic heterocycle. Examples of the nitrogen-containing aromatic heterocycle represented by Z ²³ and Z ²⁴ include pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, triazine ring, imidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadi Examples include an azole ring, a thiadiazole ring, a thiophene ring, and a furan ring. From the viewpoint of stability of the complex, emission wavelength control and emission quantum yield, the ring represented by Z ²³ and Z ²⁴ is preferably a benzene ring, a pyridine ring, a pyrazine ring, an imidazole ring, a pyrazole ring, or a thiophene ring. More preferred are a benzene ring, a pyridine ring and a pyrazole ring, and still more preferred are a benzene ring and a pyridine ring.

Of the platinum (Pt) complexes represented by the general formula (C-2), one of the more preferred embodiments is a platinum (Pt) complex represented by the following general formula (C-4).

(In the general formula (C-4), A ⁴⁰¹ to A ⁴¹⁴ each independently represents C—R or a nitrogen atom. R represents a hydrogen atom or a substituent. L ⁴¹ represents a single bond or a divalent linking group. To express.)

The general formula (C-4) will be described.
A ⁴⁰¹ to A ⁴¹⁴ each independently represents C—R or a nitrogen atom. R represents a hydrogen atom or a substituent.
As the substituent represented by R, those exemplified as the substituent group A can be applied.
A ⁴⁰¹ to A ⁴⁰⁶ are preferably C—R, and Rs may be connected to each other to form a ring. When A ⁴⁰¹ to A ⁴⁰⁶ are C—R, R in A ⁴⁰² and A ⁴⁰⁵ is preferably a hydrogen atom, an alkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a fluorine atom, or a cyano group. More preferred are a hydrogen atom, an amino group, an alkoxy group, an aryloxy group and a fluorine atom, and particularly preferred are a hydrogen atom and a fluorine atom. R in A ⁴⁰¹ , A ⁴⁰³ , A ⁴⁰⁴ and A ⁴⁰⁶ is preferably a hydrogen atom, an alkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a fluorine atom or a cyano group, more preferably a hydrogen atom or amino Group, an alkoxy group, an aryloxy group and a fluorine atom, and particularly preferably a hydrogen atom.
L ⁴¹ has the same meaning as L ^{1 in} formula (C-1), and the preferred range is also the same.

As A ⁴⁰⁷ to A ⁴¹⁴ , in each of A ⁴⁰⁷ to A ⁴¹⁰ and A ⁴¹¹ to A ⁴¹⁴ , the number of N (nitrogen atoms) is preferably 0 to 2, and more preferably 0 to 1. In the case of shifting the emission wavelength to the short wavelength side, either A ⁴⁰⁸ or A ⁴¹² is preferably a nitrogen atom, and more preferably both A ⁴⁰⁸ and A ⁴¹² are nitrogen atoms.

Of the platinum (Pt) complexes represented by the general formula (C-2), one of the more preferred embodiments is a platinum (Pt) complex represented by the following general formula (C-5).

(In the general formula (C-5), A ⁵⁰¹ to A ⁵¹² each independently represents C—R or a nitrogen atom, R represents a hydrogen atom or a substituent, and L ⁵¹ represents a single bond or a divalent linkage. Represents a group.)

The general formula (C-5) will be described. A ⁵⁰¹ to A ⁵⁰⁶ and L ⁵¹ have the same ^{meanings as} A ⁴⁰¹ to A ⁴⁰⁶ and L ⁴¹ in formula (C-4), and preferred ranges thereof are also the same.

A ⁵⁰⁷ , A ⁵⁰⁸ and A ⁵⁰⁹ and A ⁵¹⁰ , A ⁵¹¹ and A ⁵¹² and each independently represent C—R or a nitrogen atom. R represents a hydrogen atom or a substituent. As the substituent represented by R, those exemplified as the substituent group A can be applied.

Among the platinum (Pt) complexes represented by the general formula (C-1), another more preferable embodiment is a platinum (Pt) complex represented by the following general formula (C-6).

(In the formula, L ⁶¹ represents a single bond or a divalent linking group. A ⁶¹ independently represents a carbon atom or a nitrogen atom. Z ⁶¹ and Z ⁶² each independently represent a nitrogen-containing aromatic heterocycle. Z ⁶³ independently represents a benzene ring or an aromatic heterocycle, and Y is an anionic acyclic ligand bonded to platinum (Pt).

The general formula (C-6) will be described. L ⁶¹ has the same meaning as L ^{1 in} formula (C-1), and the preferred range is also the same.

A ⁶¹ represents a carbon atom or a nitrogen atom. In view of the stability of the complex and the light emission quantum yield of the complex, A ⁶¹ is preferably a carbon atom.

Z ⁶¹ and Z ⁶² are synonymous with Z ²¹ and Z ²² in the general formula (C-2), respectively, and preferred ranges thereof are also the same. Z ⁶³ has the same meaning as Z ²³ in formula (C-2), and the preferred range is also the same.

Y is an anionic acyclic ligand that binds to platinum (Pt). An acyclic ligand is one in which atoms bonded to platinum (Pt) do not form a ring in the state of a ligand. As an atom couple | bonded with platinum (Pt) in Y, a carbon atom, a nitrogen atom, an oxygen atom, and a sulfur atom are preferable, a nitrogen atom and an oxygen atom are more preferable, and an oxygen atom is the most preferable.
A vinyl ligand is mentioned as Y couple | bonded with platinum (Pt) by a carbon atom. Examples of Y bonded to platinum (Pt) with a nitrogen atom include an amino ligand and an imino ligand. Examples of Y bonded to platinum (Pt) with an oxygen atom include an alkoxy ligand, an aryloxy ligand, a heteroaryloxy ligand, an acyloxy ligand, a silyloxy ligand, a carboxyl ligand, and a phosphate group. Examples thereof include ligands and sulfonic acid ligands. Examples of Y bonded to platinum (Pt) with a sulfur atom include alkyl mercapto ligands, aryl mercapto ligands, heteroaryl mercapto ligands, and thiocarboxylic acid ligands.
The ligand represented by Y may have a substituent, and those listed as the substituent group A can be appropriately applied as the substituent. Moreover, substituents may be connected to each other.

The ligand represented by Y is preferably a ligand bonded to platinum (Pt) with an oxygen atom, and more preferably an acyloxy ligand, an alkyloxy ligand, an aryloxy ligand, a heteroaryloxy A ligand and a silyloxy ligand are preferable, and an acyloxy ligand is more preferable.

Of the platinum (Pt) complexes represented by the general formula (C-6), one of the more preferred embodiments is a platinum (Pt) complex represented by the following general formula (C-7).

(Wherein A ⁷⁰¹ to A ⁷¹⁰ each independently represents C—R or a nitrogen atom, R represents a hydrogen atom or a substituent, L ⁷¹ represents a single bond or a divalent linking group, Y represents (It is an anionic acyclic ligand that binds to platinum (Pt).)

The general formula (C-7) will be described. L ⁷¹ has the same meaning as L ^{61 in} formula (C-6), and the preferred range is also the same. A ⁷⁰¹ to A ⁷¹⁰ have the same ^{meanings as} A ⁴⁰¹ to A ⁴¹⁰ in formula (C-4), and the preferred ranges are also the same. Y has the same meaning as Y in formula (C-6), and the preferred range is also the same.

Specific examples of the platinum (Pt) complex represented by the general formula (C-1) include [0143] to [0152], [0157] to [0158], and [0162] to JP-A-2005-310733. Compounds described in [0168], compounds described in JP-A-2006-256999, [0065]-[0083], compounds described in JP-A-2006-93542, [0065]-[0090], JP-A The compounds described in [0063] to [0071] of 2007-73491, the compounds described in [0079] to [0083] of JP 2007-324309, and [0065] to [0065] of JP 2006-93542 A Compounds described in [0090], compounds described in [0055] to [0071] of JP-A-2007-96255, JP-A-2006-31379 No. [0043] - [0046] can be mentioned publications, other include platinum (Pt) complex exemplified below.

The platinum (Pt) complex compound represented by the general formula (C-1) is described in, for example, Journal of Organic Chemistry 53,786, (1988), G.A. R. Newkome et al. ), Page 789, method described in left column 53 to right column 7, line 790, method described in left column 18 to 38, method 790, method described in right column 19 to 30 and The combination, Chemische Berichte 113, 2749 (1980), H.C. Lexy et al.), Page 2752, lines 26 to 35, and the like.
For example, a ligand or a dissociated product thereof and a metal compound are mixed with a solvent (for example, a halogen solvent, an alcohol solvent, an ether solvent, an ester solvent, a ketone solvent, a nitrile solvent, an amide solvent, a sulfone solvent, In the presence of a sulfoxide solvent, water, etc., or in the absence of a solvent, in the presence of a base (inorganic and organic bases such as sodium methoxide, t-butoxypotassium, triethylamine, potassium carbonate, etc.) Or in the absence of a base, at room temperature or below, or by heating (in addition to normal heating, a method of heating with a microwave is also effective).

The content of the compound represented by formula (C-1) in the light emitting layer of the present invention is preferably 1 to 30% by mass, more preferably 3 to 25% by mass in the light emitting layer. More preferably, it is 20 mass%.

The type of the fluorescent material is not particularly limited. For example, benzoxazole, benzimidazole, benzothiazole, styrylbenzene, polyphenyl, diphenylbutadiene, tetraphenylbutadiene, naphthalimide, coumarin, pyran, perinone, oxa Diazole, aldazine, pyralidine, cyclopentadiene, bisstyrylanthracene, quinacridone, pyrrolopyridine, thiadiazolopyridine, cyclopentadiene, styrylamine, condensed polycyclic aromatic compounds (anthracene, phenanthroline, pyrene, fluoranthene, perylene, rubrene, or Pentacene, etc.), metal complexes of 8-quinolinol, various metal complexes represented by pyromethene complexes and rare earth complexes, polythiophene, polyphenylene, polyphenyle Polymeric compounds such as vinylene, organic silane, and may be derivatives of these.

The thickness of the light emitting layer is not particularly limited, but is usually preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm, and more preferably 10 nm to 100 nm, from the viewpoint of external quantum efficiency. More preferably.

The light emitting layer in the organic electroluminescent element of the present invention may be composed only of a light emitting material, or may be a mixed layer of a host material and a light emitting material. The kind of the light emitting material may be one kind or two or more kinds. The host material is preferably a charge transport material. The host material may be one kind or two or more kinds, and examples thereof include a configuration in which an electron transporting host material and a hole transporting host material are mixed. Furthermore, the light emitting layer may contain a material that does not have charge transporting properties and does not emit light.
Further, the light emitting layer may be a single layer or a multilayer of two or more layers, and each layer may contain the same light emitting material or host material, or each layer may contain a different material. When there are a plurality of light emitting layers, each of the light emitting layers may emit light with different emission colors.

(Host material)
The host material is a compound mainly responsible for charge injection and transport in the light emitting layer, and itself is a compound that does not substantially emit light. Here, “substantially does not emit light” means that the amount of light emitted from the compound that does not substantially emit light is preferably 5% or less, more preferably 3% or less of the total amount of light emitted from the entire device. Preferably it says 1% or less.
As the host material, a compound represented by the general formula (1) can be used.

Examples of other host materials that can be used in the organic electroluminescence device of the present invention include the following compounds.
Pyrrole, indole, carbazole, azaindole, azacarbazole, triazole, oxazole, oxadiazole, pyrazole, imidazole, thiophene, benzothiophene, dibenzothiophene, furan, benzofuran, dibenzofuran, polyarylalkane, pyrazoline, pyrazolone, phenylenediamine, aryl Amines, amino-substituted chalcones, styrylanthracenes, fluorenones, hydrazones, stilbenes, silazanes, aromatic tertiary amine compounds, styrylamine compounds, porphyrin compounds, condensed aromatic hydrocarbon compounds (fluorene, naphthalene, phenanthrene, triphenylene, etc.) , Polysilane compound, poly (N-vinylcarbazole), aniline copolymer, thiophene oligomer, polythiophene Conductive polymer oligomer, organic silane, carbon film, pyridine, pyrimidine, triazine, imidazole, pyrazole, triazole, oxazole, oxadiazol, fluorenone, anthraquinodimethane, anthrone, diphenylquinone, thiopyrandi Oxides, carbodiimides, fluorenylidenemethane, distyrylpyrazine, fluorine-substituted aromatic compounds, heterocyclic tetracarboxylic anhydrides such as naphthaleneperylene, metal complexes of phthalocyanines and 8-quinolinol derivatives, metal phthalocyanines, benzoxazoles, Examples thereof include various metal complexes represented by metal complexes having benzothiazol as a ligand and derivatives thereof (which may have a substituent or a condensed ring).
Of these, carbazole, dibenzothiophene, dibenzofuran, arylamine, fused aromatic hydrocarbon compounds, and metal complexes are particularly preferable.

The host material that can be used in combination in the light emitting layer of the organic electroluminescent device of the present invention may be a hole transporting host material or an electron transporting host material.

In the light emitting layer, the triplet lowest excitation energy (T ₁ energy) in the film state of the host material is preferably higher than the T ₁ energy of the phosphorescent light emitting material in terms of color purity, light emission efficiency, and driving durability. It is preferable T ₁ is greater 0.1eV higher than the T ₁ of the phosphorescent material of the host material, more preferably at least 0.2eV higher, and further preferably more than 0.3eV large.
T ₁ of the a film state of the host material is a large T ₁ is obtained from the phosphorescent material to the host material for thereby quench T ₁ is less than the light emission of the phosphorescent material. Even if the T _{1 of} the host material is larger than the phosphorescent light emitting material, if the difference in T ₁ between the two is small, the reverse energy transfer from the phosphorescent light emitting material to the host material occurs in part, resulting in a decrease in efficiency and durability. Cause. Therefore, there is a demand for a host material having a sufficiently large T ₁ and high chemical stability and carrier injection / transport properties.

In addition, the content of the host compound in the light emitting layer in the organic electroluminescent device of the present invention is not particularly limited, but is 15 mass with respect to the total compound mass forming the light emitting layer from the viewpoint of light emission efficiency and driving voltage. % Or more and 95% by mass or less is preferable. When the light emitting layer contains a plurality of types of host compounds including the compound represented by the general formula (1), the compound represented by the general formula (1) is 50% by mass or more and 99% by mass or less in all the host compounds. It is preferable.

(Other layers)
The organic electroluminescent element of the present invention may have other layers other than the light emitting layer.
Other organic layers other than the light emitting layer that the organic layer may have include a hole injection layer, a hole transport layer, a block layer (hole block layer, exciton block layer, electron block layer, etc.), Examples thereof include an electron transport layer. Examples of the specific layer configuration include the following, but the present invention is not limited to these configurations.
Anode / hole transport layer / light emitting layer / electron transport layer / cathode,
Anode / hole transport layer / light emitting layer / block layer / electron transport layer / cathode,
Anode / hole transport layer / light emitting layer / block layer / electron transport layer / electron injection layer / cathode,
Anode / hole injection layer / hole transport layer / light emitting layer / block layer / electron transport layer / cathode,
Anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode,
Anode / hole injection layer / hole transport layer / light emitting layer / block layer / electron transport layer / electron injection layer / cathode,
Anode / hole injection layer / hole transport layer / block layer / light emitting layer / block layer / electron transport layer / electron injection layer / cathode.
The organic electroluminescent element of the present invention preferably includes (A) at least one organic layer preferably disposed between the anode and the light emitting layer. Examples of the organic layer (A) preferably disposed between the anode and the light emitting layer include a hole injection layer, a hole transport layer, and an electron block layer from the anode side.
The organic electroluminescent element of the present invention preferably includes (B) at least one organic layer preferably disposed between the cathode and the light emitting layer. Examples of the organic layer (B) preferably disposed between the cathode and the light emitting layer include an electron injection layer, an electron transport layer, and a hole blocking layer from the cathode side.
Specifically, an example of a preferred embodiment of the organic electroluminescent element of the present invention is the embodiment described in FIG. 1, and as the organic layer, a hole injection layer 4, a hole transport layer 5, In this embodiment, the light emitting layer 6, the hole blocking layer 7, and the electron transport layer 8 are laminated in this order.
Hereinafter, other layers other than the light emitting layer which may be included in the organic electroluminescent element of the present invention will be described.

(A) Organic layer preferably disposed between the anode and the light emitting layer First, (A) the organic layer preferably disposed between the anode and the light emitting layer will be described.

(A-1) Hole injection layer, hole transport layer The hole injection layer and the hole transport layer are layers having a function of receiving holes from the anode or the anode side and transporting them to the cathode side.
For the hole injection layer and the hole transport layer, the matters described in paragraph numbers [0165] to [0167] of JP-A-2008-270736 can be applied to the present invention. Among these, the material preferably used for the hole injection layer and the hole transport layer will be described.

The organic electroluminescent element of the present invention preferably contains the following compound in the organic layer between the light emitting layer and the anode, and more preferably in the hole injection layer.
Specifically, a compound having the following structure is preferable.

The organic electroluminescent element of the present invention preferably contains at least one compound represented by the following general formula (M-1) in the organic layer between the light emitting layer and the anode, and the hole transport layer contains It is more preferable to contain.

In general formula (M-1), Ar ₁ and Ar ₂ are each independently one or more selected from alkyl, aryl, heteroaryl, arylamino, alkylamino, morpholino, thiomorpholino, N, O, and S It represents a 5- or 6-membered heterocycloalkyl or cycloalkyl containing a hetero atom, and may further have a substituent Z. Ar ₁ and Ar ₂ may be bonded to each other by a single bond, alkylene, or alkenylene (with or without a condensed ring) to form a condensed 5- to 9-membered ring.
Ar ₃ represents alkyl, aryl, heteroaryl, or arylamino, and may further have a substituent Z.
Z is independently a halogen atom, -R ", -OR", -N (R ") ₂ , -SR", -C (O) R ", -C (O) OR", -C (O) _{N (R ") 2, -CN} , -NO 2, -SO 2, -SOR", - SO 2 R ", or -SO ₃ R" represents, R "are each independently a hydrogen atom, an alkyl group, A perhaloalkyl group, an alkenyl group, an alkynyl group, a heteroalkyl group, an aryl group or a heteroaryl group is represented.
p is an integer of 1 to 4, and when p is 2 or more, Ar ₁ and Ar ₂ may be the same or different.

Another preferred embodiment of the compound represented by the general formula (M-1) is a case represented by the following general formula (M-3).

In the general formula (M-3), R ^S1 to R ^S5 are each independently an alkyl group, cycloalkyl group, alkenyl group, alkynyl group, —CN, perfluoroalkyl group, trifluorovinyl group, —CO ₂ R, —C (O) R, —NR ₂ , —NO ₂ , —OR, a halogen atom, an aryl group or a heteroaryl group, which may further have a substituent Z. Each R independently represents a hydrogen atom, an alkyl group, a perhaloalkyl group, an alkenyl group, an alkynyl group, a heteroalkyl group, an aryl group or a heteroaryl group. When a plurality of R ^S1 to R ^S5 are present, they may be bonded to each other to form a ring, and may further have a substituent Z.
a represents an integer of 0 to 4, and when a plurality of R ^S1 are present, they may be the same or different and may be bonded to each other to form a ring. b to e each independently represent an integer of 0 to 5, and when there are a plurality of R ^S2 to R ^S5 , respectively, they may be the same or different, and any two may be bonded to form a ring. Good.
q is an integer of 1 to 5, and when q is 2 or more, a plurality of R ^S1 may be the same or different, and may be bonded to each other to form a ring.

The alkyl group may have a substituent, may be saturated or unsaturated, and examples of the group that may be substituted include the above-described substituent Z. The alkyl group represented by R ^S1 to R ^S5 is preferably an alkyl group having 1 to 8 carbon atoms in total, more preferably an alkyl group having 1 to 6 carbon atoms in total, such as a methyl group or an ethyl group. , I-propyl group, cyclohexyl group, t-butyl group and the like.
The cycloalkyl group may have a substituent, may be saturated or unsaturated, and examples of the group that may be substituted include the above-described substituent Z. The cycloalkyl group represented by R ^S1 to R ^S5 is preferably a cycloalkyl group having 4 to 7 ring members, more preferably a cycloalkyl group having 5 to 6 carbon atoms in total, such as a cyclopentyl group or cyclohexyl group. Groups and the like.
The alkenyl group represented by R ^S1 to R ^S5 preferably has 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 2 to 10 carbon atoms. For example, vinyl, allyl, 1-propenyl, Examples include 1-isopropenyl, 1-butenyl, 2-butenyl, 3-pentenyl and the like.
The alkynyl group represented by R ^S1 to R ^S5 preferably has 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 2 to 10 carbon atoms. For example, ethynyl, propargyl, 1-propynyl , 3-pentynyl and the like.

^Examples of the perfluoroalkyl group represented by R ^S1 to R ^S5 include those in which all the hydrogen atoms of the aforementioned alkyl group are replaced with fluorine atoms.

The aryl group represented by R ^S1 to R ^S5 is preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, such as a phenyl group, a tolyl group, a biphenyl group, and a terphenyl group.

The heteroaryl group represented by R ^S1 to R ^S5 is preferably a heteroaryl group having 5 to 8 carbon atoms, more preferably a 5- or 6-membered substituted or unsubstituted heteroaryl group, For example, pyridyl group, pyrazinyl group, pyridazinyl group, pyrimidinyl group, triazinyl group, quinolinyl group, isoquinolinyl group, quinazolinyl group, cinnolinyl group, phthalazinyl group, quinoxalinyl group, pyrrolyl group, indolyl group, furyl group, benzofuryl group, thienyl group, Benzothienyl, pyrazolyl, imidazolyl, benzimidazolyl, triazolyl, oxazolyl, benzoxazolyl, thiazolyl, benzothiazolyl, isothiazolyl, benzisothiazolyl, thiadiazolyl, isoxazolyl, benzisoxa Examples include zolyl group, pyrrolidinyl group, piperidinyl group, piperazinyl group, imidazolidinyl group, thiazolinyl group, sulfolanyl group, carbazolyl group, dibenzofuryl group, dibenzothienyl group, pyridoindolyl group and the like. Preferred examples include pyridyl group, pyrimidinyl group, imidazolyl group, and thienyl group, and more preferred are pyridyl group and pyrimidinyl group.

R ^S1 to R ^S5 are preferably a hydrogen atom, an alkyl group, a cyano group, a trifluoromethyl group, a perfluoroalkyl group, a dialkylamino group, a fluoro group, an aryl group, or a heteroaryl group, and more preferably a hydrogen atom, an alkyl group Group, cyano group, trifluoromethyl group, fluoro group and aryl group, more preferably a hydrogen atom, an alkyl group and an aryl group. As the substituent Z, an alkyl group, an alkoxy group, a fluoro group, a cyano group, and a dialkylamino group are preferable, and a hydrogen atom and an alkyl group are more preferable.

Any two of R ^S1 to R ^S5 may be bonded to each other to form a condensed 4- to 7-membered ring, and the condensed 4- to 7-membered ring is cycloalkyl, aryl, or heteroaryl; The 7-membered ring may further have a substituent Z. The definition and preferred range of cycloalkyl, aryl, and heteroaryl formed are the same as the cycloalkyl group, aryl group, and heteroaryl group defined by R ^S1 to R ^S5 .

When the compound represented by the general formula (M-1) is used in the hole transport layer, the compound represented by the general formula (M-1) is preferably contained in an amount of 50 to 100% by mass, The content is preferably 100% by mass, and particularly preferably 95 to 100% by mass.
In addition, when the compound represented by the general formula (M-1) is used in a plurality of organic layers, it is preferable that each layer contains the above-mentioned range.

The compound represented by the general formula (M-1) may contain only one kind in any organic layer, and the compound represented by the plurality of general formulas (M-1) You may contain in combination.

The thickness of the hole transport layer containing the compound represented by the general formula (M-1) is preferably 1 nm to 500 nm, more preferably 3 nm to 200 nm, and more preferably 5 nm to 100 nm. Further preferred. The hole transport layer is preferably provided in contact with the light emitting layer.
The hole transport layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.

The lowest excited triplet (T ₁ ) energy in the film state of the compound represented by the general formula (M-1) is preferably 2.52 eV (58 kcal / mol) or more and 3.47 eV (80 kcal / mol) or less. EV (57 kcal / mol) or more and 3.25 eV (75 kcal / mol) or less, more preferably 2.52 eV (58 kcal / mol) or more and 3.04 eV (70 kcal / mol) or less.

The hydrogen atom constituting the general formula (M-1) includes hydrogen isotopes (such as deuterium atoms). In this case, all hydrogen atoms in the compound may be replaced with hydrogen isotopes, or a mixture in which a part is a compound containing hydrogen isotopes may be used.

The compound represented by the general formula (M-1) can be synthesized by combining various known synthesis methods. Most commonly, carbazole compounds are synthesized by dehydroaromatization after the Athercorp rearrangement reaction of a condensate of an aryl hydrazine and a cyclohexane derivative (LF Tieze, by Th. Eicher, translated by Takano, Ogasawara, Precision organic synthesis, page 339 (published by Nankodo). Regarding the coupling reaction of the obtained carbazole compound and halogenated aryl compound using a palladium catalyst, Tetrahedron Letters 39: 617 (1998), 39: 2367 (1998) and 40: 6393 (1999) and the like. The reaction temperature and reaction time are not particularly limited, and the conditions described in the above literature can be applied.

The compound represented by the general formula (M-1) of the present invention is preferably formed into a thin layer by a vacuum deposition process, but a wet process such as solution coating can also be suitably used. The molecular weight of the compound is preferably 2000 or less, more preferably 1200 or less, and particularly preferably 800 or less from the viewpoints of deposition suitability and solubility. Also, from the viewpoint of vapor deposition suitability, if the molecular weight is too small, the vapor pressure becomes small, the change from the gas phase to the solid phase does not occur, and it is difficult to form an organic layer. Particularly preferred.

As the hole transport material, among the compounds represented by the general formula (M-1), a compound having the following structure is preferable.

The hole injection layer preferably contains an electron accepting dopant. By containing an electron-accepting dopant in the hole injection layer, hole injection properties are improved, driving voltage is lowered, and efficiency is improved. The electron-accepting dopant may be any organic material or inorganic material as long as it can extract electrons from the doped material and generate radical cations. For example, tetracyanoquinodimethane ( TCNQ), tetrafluorotetracyanoquinodimethane (F ₄ -TCNQ), molybdenum oxide and the like.

The electron-accepting dopant in the hole injection layer is preferably contained in an amount of 0.01% by mass to 50% by mass, and preferably 0.1% by mass to 40% by mass with respect to the total mass of the compound forming the hole injection layer. %, More preferably 0.2% by mass to 30% by mass.

(A-2) Electron Blocking Layer The electron blocking layer is a layer having a function of preventing electrons transported from the cathode side to the light emitting layer from passing through to the anode side. In the present invention, an electron blocking layer can be provided as an organic layer adjacent to the light emitting layer on the anode side.
As an example of the organic compound constituting the electron blocking layer, for example, those mentioned as the hole transport material described above can be applied.
The thickness of the electron blocking layer is preferably 1 nm to 500 nm, more preferably 3 nm to 100 nm, and even more preferably 5 nm to 50 nm.
The electron blocking layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.
The material used for the electron blocking layer is preferably higher than the T ₁ energy of the phosphorescent material in terms of color purity, luminous efficiency, and driving durability. It is preferable T ₁ is greater than 0.1eV than T ₁ of the phosphorescent material in the film state of the material used for the electron blocking layer, it is more preferably at least 0.2eV higher, and further preferably more than 0.3eV large.

(B) Organic layer preferably disposed between the cathode and the light emitting layer Next, the (B) organic layer preferably disposed between the cathode and the light emitting layer will be described.

(B-1) Electron Injection Layer, Electron Transport Layer The electron injection layer and the electron transport layer are layers having a function of receiving electrons from the cathode or the cathode side and transporting them to the anode side. The electron injection material and the electron transport material used for these layers may be a low molecular compound or a high molecular compound.
As the electron transport material, the compound represented by the general formula (1) can be used, and a preferable embodiment thereof is a case where the compound represented by the general formula (1) is contained in a layer other than the light emitting layer. As explained. Other electron transport materials include pyridine derivatives, quinoline derivatives, pyrimidine derivatives, pyrazine derivatives, phthalazine derivatives, phenanthroline derivatives, triazine derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, fluorenone derivatives, anthraquinodimethane. Derivatives, anthrone derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, aromatic ring tetracarboxylic anhydrides such as naphthalene and perylene, phthalocyanine derivatives, 8-quinolinol derivatives Represented by metal complexes, metal phthalocyanines, various metal complexes represented by metal complexes with benzoxazole and benzothiazole ligands, and siloles Organosilane derivatives, a layer containing such is preferable.

The thicknesses of the electron injection layer and the electron transport layer are each preferably 500 nm or less from the viewpoint of lowering the driving voltage.
The thickness of the electron transport layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and even more preferably 10 nm to 100 nm. The thickness of the electron injection layer is preferably from 0.1 nm to 200 nm, more preferably from 0.2 nm to 100 nm, and even more preferably from 0.5 nm to 50 nm.
The electron injection layer and the electron transport layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.

The electron injection layer preferably contains an electron donating dopant. By including an electron donating dopant in the electron injection layer, the electron injection property is improved, the driving voltage is lowered, and the efficiency is improved. The electron donating dopant may be any organic material or inorganic material as long as it can give electrons to the doped material and generate radical anions. For example, tetrathiafulvalene (TTF) And dithiaimidazole compounds such as tetrathianaphthacene (TTT) and bis- [1,3 diethyl-2-methyl-1,2-dihydrobenzimidazolyl], lithium, cesium and the like.

The electron donating dopant in the electron injection layer is preferably contained in an amount of 0.01% by mass to 50% by mass, and 0.1% by mass to 40% by mass with respect to the total mass of the compound forming the electron injection layer. More preferably, the content is 0.5 to 30% by mass.

(B-2) Hole blocking layer The hole blocking layer is a layer having a function of preventing holes transported from the anode side to the light emitting layer from passing through to the cathode side. In the present invention, a hole blocking layer can be provided as an organic layer adjacent to the light emitting layer on the cathode side.
The T ₁ energy in the film state of the organic compound constituting the hole blocking layer is higher than the T ₁ energy of the light emitting material in order to prevent energy transfer of excitons generated in the light emitting layer and not to reduce the light emission efficiency. It is preferable.
As an example of the organic compound constituting the hole blocking layer, the compound represented by the general formula (1) can be used.
Examples of other organic compounds constituting the hole blocking layer other than the compound represented by the general formula (1) include aluminum (III) bis (2-methyl-8-quinolinato) 4-phenylphenolate ( Aluminum complexes such as aluminum (III) bis (2-methyl-8-quinolinato) 4-phenylphenolate (abbreviated as Balq)), triazole derivatives, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline ( And phenanthroline derivatives such as 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (abbreviated as BCP)) and the compounds of the present invention. In the present invention, the hole blocking layer is not limited to the function of actually blocking holes, and the exciton of the light emitting layer may not diffuse into the electron transport layer, or may have a function of blocking energy transfer quenching. . The compound of the present invention can also be preferably applied as a hole blocking layer.
The thickness of the hole blocking layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and even more preferably 10 nm to 100 nm.
The hole blocking layer may have a single layer structure made of one or more of the materials described above, or may have a multilayer structure made of a plurality of layers having the same composition or different compositions.
The material used for the hole blocking layer is preferably higher than the T ₁ energy of the phosphorescent light emitting material in terms of color purity, light emission efficiency, and driving durability. Holes T ₁ of the at film state of the material used in the blocking layer is preferably greater 0.1eV higher than the T ₁ of the phosphorescent material, more preferably at least 0.2eV higher, and further preferably more than 0.3eV greater .

(B-3) Material particularly preferably used for the organic layer preferably disposed between the cathode and the light emitting layer The organic electroluminescent element of the present invention is preferably disposed between the (B) cathode and the light emitting layer. As a material that is particularly preferably used for the material of the organic layer, a compound represented by the general formula (1) and a compound represented by the following general formula (O-1) can be given.
Hereinafter, the compound represented by the general formula (O-1) will be described.

The organic electroluminescent device of the present invention preferably includes at least one organic layer between the light emitting layer and the cathode, and the organic layer contains at least one compound represented by the following general formula (O-1). It is preferable from the viewpoint of device efficiency and driving voltage. The general formula (O-1) will be described below.

(In the general formula (O1), R ^O1 represents an alkyl group, an aryl group, or each independently .A ^O1 ~ A ^O4 representing the heteroaryl group, the C-R ^A or .R ^A representing the nitrogen atom Represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group, and a plurality of R ^A may be the same or different, L ^O1 represents a divalent to hexavalent linking group comprising an aryl ring or a heteroaryl ring; N ^O1 represents an integer of 2 to 6.)

R ^O1 represents an alkyl group (preferably having 1 to 8 carbon atoms), an aryl group (preferably having 6 to 30 carbon atoms), or a heteroaryl group (preferably having 4 to 12 carbon atoms). It may have a substituent selected from group A. R ^O1 is preferably an aryl group or a heteroaryl group, more preferably an aryl group. A preferable substituent when the aryl group of R ^O1 has a substituent includes an alkyl group, an aryl group or a cyano group, more preferably an alkyl group or an aryl group, and still more preferably an aryl group. When the aryl group of R ^O1 has a plurality of substituents, the plurality of substituents may be bonded to each other to form a 5- or 6-membered ring. The aryl group of R ^O1 is preferably a phenyl group which may have a substituent selected from the substituent group A, more preferably a phenyl group which may be substituted with an alkyl group or an aryl group, More preferred is an unsubstituted phenyl group or 2-phenylphenyl group.

A ^O1 to A ^O4 each independently represent C—R ^A or a nitrogen atom. Of A ^O1 to A ^O4 , 0 to 2 are preferably nitrogen atoms, more preferably 0 or 1 is a nitrogen atom. Or all of A ^O1 ~ A ^O4 is C-R ^A, or A ^O1 be a nitrogen atom, is preferably A ^O2 ~ A ^O4 is C-R ^A, A ^O1 be a nitrogen atom, A ^O2 ~ More preferably, A ^O4 is C—R ^A , A ^O1 is a nitrogen atom, A ^O2 to A ^O4 are C—R ^A , and R ^A is all hydrogen atoms.

R ^A represents a hydrogen atom, an alkyl group (preferably having a carbon number of 1 to 8), an aryl group (preferably having a carbon number of 6 to 30), or a heteroaryl group (preferably having a carbon number of 4 to 12). It may have a substituent selected from the substituent group A. The plurality of R ^A may be the same or different. R ^A is preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom.

L ^O1 represents a divalent to hexavalent linking group consisting of an aryl ring (preferably having 6 to 30 carbon atoms) or a heteroaryl ring (preferably having 4 to 12 carbon atoms). L ^O1 is preferably an arylene group, heteroarylene group, aryltriyl group, or heteroaryltriyl group, more preferably a phenylene group, a biphenylene group, or a benzenetriyl group, still more preferably a biphenylene group, Or it is a benzenetriyl group. L ^O1 may have a substituent selected from the aforementioned substituent group A, and the alkyl group, aryl group, or cyano group is preferred as the substituent when it has a substituent. Specific examples of L ^O1 include the following.

n ^O1 represents an integer of 2 to 6, preferably an integer of 2 to 4, more preferably 2 or 3. n ^O1 is most preferably 3 in terms of device efficiency, and most preferably 2 in terms of device durability.
The compound represented by the general formula (O-1) is more preferably a compound represented by the following general formula (O-2).

(In the general formula (O-2), R ^O1 represents an alkyl group, an aryl group, or a heteroaryl group. R ^O2 to R ^O4 each independently represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group. A ^O1 to A ^O4 each independently represent C—R ^A or a nitrogen atom, R ^A represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group, and a plurality of R ^A are the same or different. May be.)

R ^O1 and A ^O1 ~ A ^O4, the general formula (O1) in the same meaning as R ^O1 and A ^O1 ~ A ^O4 of, also the same preferable ranges thereof.
R ⁰² to R ⁰⁴ are each independently a hydrogen atom, an alkyl group (preferably having 1 to 8 carbon atoms), an aryl group (preferably having 6 to 30 carbon atoms), or a heteroaryl group (preferably having 4 to 12 carbon atoms). These may have a substituent selected from the aforementioned substituent group A. R ⁰² to R ⁰⁴ are preferably a hydrogen atom, an alkyl group, or an aryl group, more preferably a hydrogen atom or an aryl group, and most preferably a hydrogen atom.

The compound represented by the general formula (O-1) has a glass transition temperature (Tg) of 100 ° C. from the viewpoint of stable operation at high temperature storage, stable operation against high temperature driving, and heat generation during driving. It is preferably from ˜300 ° C., more preferably from 120 ° C. to 300 ° C., further preferably from 120 ° C. to 300 ° C., and still more preferably from 140 ° C. to 300 ° C.

Specific examples of the compound represented by the general formula (O-1) are shown below, but the present invention is not limited thereto.

The compound represented by the general formula (O-1) can be synthesized by the method described in JP-A No. 2001-335776. After synthesis, purification by column chromatography, recrystallization, reprecipitation, etc., followed by purification by sublimation is preferred. Not only can organic impurities be separated by sublimation purification, but inorganic salts, residual solvents, moisture, and the like can be effectively removed.

In the organic electroluminescent device of the present invention, the compound represented by the general formula (O-1) is preferably contained in the organic layer between the light emitting layer and the cathode, but the cathode side layer adjacent to the light emitting layer is used. It is more preferable that it is contained.
The compound represented by the general formula (O-1) is preferably contained in an amount of 70 to 100% by mass, and more preferably 85 to 100% by mass with respect to the total mass of the organic layer to be added.

<Protective layer>
In the present invention, the entire organic electroluminescent element may be protected by a protective layer.
As for the protective layer, the matters described in JP-A-2008-270736, paragraphs [0169] to [0170] can be applied to the present invention. The material for the protective layer may be inorganic or organic.

<Sealing container>
The organic electroluminescent element of the present invention may be sealed entirely using a sealing container.
Regarding the sealing container, the matters described in paragraph [0171] of JP-A-2008-270736 can be applied to the present invention.

(Driving method)
The organic electroluminescence device of the present invention emits light by applying a direct current (which may include an alternating current component as necessary) voltage (usually 2 to 15 volts) or a direct current between the anode and the cathode. Obtainable.
The driving method of the organic electroluminescence device of the present invention is described in JP-A-2-148687, JP-A-6-301355, JP-A-5-290080, JP-A-7-134558, JP-A-8-234585, and JP-A-8-2441047. The driving methods described in each publication, Japanese Patent No. 2784615, US Pat. Nos. 5,828,429 and 6,023,308 can be applied.

The external quantum efficiency of the organic electroluminescent element of the present invention is preferably 7% or more, more preferably 10% or more, and further preferably 12% or more. The value of the external quantum efficiency should be the maximum value of the external quantum efficiency when the device is driven at 20 ° C., or the value of the external quantum efficiency in the vicinity of 300 to 400 cd / m ² when the device is driven at 20 ° C. Can do.

The internal quantum efficiency of the organic electroluminescence device of the present invention is preferably 30% or more, more preferably 50% or more, and further preferably 70% or more. The internal quantum efficiency of the device is calculated by dividing the external quantum efficiency by the light extraction efficiency. In a normal organic EL element, the light extraction efficiency is about 20%. However, the shape of the substrate, the shape of the electrode, the thickness of the organic layer, the thickness of the inorganic layer, the refractive index of the organic layer, the refractive index of the inorganic layer, etc. By devising it, it is possible to increase the light extraction efficiency to 20% or more.

<Peak emission wavelength>
The organic electroluminescent element of the present invention has no limitation on the emission peak wavelength. For example, among the three primary colors of light, it may be used for red light emission, green light emission, or blue light emission. Among them, the organic electroluminescence device of the present invention preferably has an emission peak wavelength of 500 to 700 nm from the viewpoint of the lowest excited triplet (T ₁ ) energy of the compound represented by the general formula (1).
Specifically, in the organic electroluminescent device of the present invention, when the compound represented by the general formula (1) is used as the host material of the light emitting layer, the emission peak wavelength is preferably 500 to 700 nm. It is more preferably from ˜650 nm, particularly preferably from 520 to 550 nm.
On the other hand, in the organic electroluminescence device of the present invention, when the compound represented by the general formula (1) is used as a charge transport material for the hole blocking layer, the emission peak wavelength is preferably 400 to 700 nm, It is more preferably from ˜650 nm, particularly preferably from 500 to 650 nm.

<Use of the organic electroluminescent device of the present invention>
The organic electroluminescent element of the present invention can be suitably used for a display element, a display, a backlight, an electrophotography, an illumination light source, a recording light source, an exposure light source, a reading light source, a sign, a signboard, an interior, or optical communication. In particular, it is preferably used for a device that is driven in a region where light emission luminance is high, such as a light emitting device, a lighting device, and a display device.

[Light emitting device]
The light emitting device of the present invention includes the organic electroluminescent element of the present invention.
Next, the light emitting device of the present invention will be described with reference to FIG.
The light emitting device of the present invention uses the organic electroluminescent element.
FIG. 2 is a cross-sectional view schematically showing an example of the light emitting device of the present invention. The light-emitting device 20 of FIG. 2 is comprised by the board | substrate (support substrate) 2, the organic electroluminescent element 10, the sealing container 16, etc. FIG.

The organic electroluminescent device 10 is configured by sequentially laminating an anode (first electrode) 3, an organic layer 11, and a cathode (second electrode) 9 on a substrate 2. A protective layer 12 is laminated on the cathode 9, and a sealing container 16 is provided on the protective layer 12 with an adhesive layer 14 interposed therebetween. In addition, a part of each

electrode

3 and 9, a partition, an insulating layer, etc. are abbreviate | omitted.
Here, as the adhesive layer 14, a photocurable adhesive such as an epoxy resin or a thermosetting adhesive can be used, and for example, a thermosetting adhesive sheet can also be used.

The use of the light-emitting device of the present invention is not particularly limited, and for example, it can be a display device such as a television, a personal computer, a mobile phone, and electronic paper in addition to a lighting device.

[Lighting device]
The illuminating device of this invention is characterized by including the organic electroluminescent element of this invention.
Next, the illumination device of the present invention will be described with reference to FIG.
FIG. 3 is a cross-sectional view schematically showing an example of the illumination device of the present invention. As shown in FIG. 3, the illumination device 40 of the present invention includes the organic EL element 10 and the light scattering member 30 described above. More specifically, the lighting device 40 is configured such that the substrate 2 of the organic EL element 10 and the light scattering member 30 are in contact with each other.
The light scattering member 30 is not particularly limited as long as it can scatter light. In FIG. 3, the light scattering member 30 is a member in which fine particles 32 are dispersed on a transparent substrate 31. As the transparent substrate 31, for example, a glass substrate can be preferably cited. As the fine particles 32, transparent resin fine particles can be preferably exemplified. As the glass substrate and the transparent resin fine particles, known ones can be used. In such an illuminating device 40, when light emitted from the organic electroluminescent element 10 is incident on the light incident surface 30A of the scattering member 30, the incident light is scattered by the light scattering member 30, and the scattered light is emitted from the light emitting surface 30B. It is emitted as illumination light.

[Display device]
The display device of the present invention includes the organic electroluminescent element of the present invention.
Examples of the display device of the present invention include a display device such as a television, a personal computer, a mobile phone, and electronic paper.

The present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

1. Synthesis Example The compound represented by the general formula (1) can be synthesized by combining known reactions.
(Synthesis Example 1)
Synthesis of compound (2-11)

To a 100 ml three-necked flask, 7.44 g of potassium triphosphate, 0.61 g of compound b, 20 ml of tetrahydrofuran and 10 ml of distilled water were added and stirred at room temperature. Next, 0.23 g of S-Phos, 2 g of compound a, and 0.13 g of Pd ₂ (dba) ₃ were added and heated to reflux for 7 hours. After the reaction, 20 ml of toluene was added, and the precipitate was filtered and washed with methanol. The obtained solid was dispersed in methanol, heated to reflux for 1 hour, filtered, washed with methanol, and dried to obtain 1.34 g of a gray solid. This was purified by sublimation to obtain compound (2-11). The obtained compound was identified by ¹ H-NMR at 400 MHz.

The ¹ H-NMR spectrum of the compound (2-11) is shown in FIG.
Details of ¹ H-NMR data of Compound 2-11 read from FIG. 4 are shown below.

Compounds (1-1), (1-3), (1-5), (1-7), (2-1), (3-2) according to the following scheme in the same manner as for compound (2-11) , (3-11), (7-10), (7-11), (7-13), (9-12), (10-3), and (10-6) were synthesized.

Details of ¹ H-NMR data of the obtained compound (1-5) are shown below.
Compound (1-5) ¹ H-NMR (CDCl ₃ ) [ppm]; 8.092 (1H, s), 8.051 (1H, s), 7.933 (1H, s), 7.903 (2H , s), 7.866 (1H, s), 7.831 (1H, s), 7.76-7.62 (11H, m), 7.55-7.44 (6H, m)

Details of ¹ H-NMR data of the obtained compound (2-1) are shown below.
¹ H-NMR (CDCl ₃ ) [ppm]; 8.50 (1H, s), 8.26 (1H, d), 8.19 (1H, s), 8.06 (2H, s), 8. 04 (1H, s), 7.94-7.88 (9H, m), 7.767 (1H, s), 7.73-7.58 (7H, m), 7.53-7.47 ( 4H, m), 7.43-7.38 (2H, m)

FIG. 5 shows the ¹ H-NMR spectrum of the compound (7-13).

The compounds synthesized as described above and used in the examples are shown below together with the comparative compounds used in the examples.

2. Element fabrication / evaluation All materials used for element fabrication were purified by sublimation, and it was confirmed by high performance liquid chromatography (Tosoh TSKgel ODS-100Z) that the purity (254 nm absorption intensity area ratio) was 99.1% or more. .

Example 1
A glass substrate having a thickness of 0.5 mm and a 2.5 cm square ITO film (manufactured by Geomat Co., Ltd., surface resistance 10 Ω / □) is placed in a cleaning container, subjected to ultrasonic cleaning in 2-propanol, and then subjected to UV-ozone treatment for 30 minutes. Went. The following organic layers were sequentially deposited on the transparent anode (ITO film) by vacuum deposition.
First layer: Compound (A) below: Film thickness 10 nm
Second layer: HTL-1: film thickness 25 nm
Third layer: Compound (1-1) and GD-1 (mass ratio 90:10): film thickness 40 nm
Fourth layer: ETL-1: film thickness 40 nm
On top of this, 0.1 nm of lithium fluoride and 100 nm of metallic aluminum were vapor-deposited in this order to form a cathode.
This laminated body is put in a glove box substituted with nitrogen gas without being exposed to the atmosphere, and sealed with a glass sealing can and an ultraviolet curable adhesive (XNR5516HV, manufactured by Nagase Ciba Co., Ltd.). The device 1 was obtained.

(Examples 2 to 11, Comparative Examples 1 to 5)
In the preparation of the element 1, the compound (1-1) in the third layer was replaced with the compound represented by the general formula (1) shown in the following Table 1 and the above-mentioned comparative compounds (1) to (5). In the same manner as in the element 1, elements of the examples and comparative examples were obtained.

(Examples 15 to 25, Comparative Examples 6 to 10)
In the preparation of the element 1, both the compound (1-1) of the third layer and the ETL-1 of the fourth layer were converted into a compound represented by the general formula (1) shown in Table 1 below and the above-mentioned comparative compound (1 To Elements 15 to 25 and Comparative Elements 6 to 10 were obtained in the same manner as Element 1, except that the compound was replaced with Comparative Compound (5).

Table 1 below shows the results of evaluating these elements from the viewpoint of efficiency, durability, and driving voltage by the following method.

(Drive voltage)
Each element is caused to emit light by applying a DC voltage so that the luminance becomes 1000 cd / m ² . The applied voltage at this time was used as an index for driving voltage evaluation. Table 1 below shows the case where the driving voltage is less than 6V, ◯, the case where it is 6V or more and less than 7V, ◯, the case where it is 7V or more and less than 8V, and the case where it is 8V or more.

(External quantum efficiency)
Using a source measure unit 2400 manufactured by Toyo Technica, a DC voltage was applied to each element to emit light, and the luminance was measured using a luminance meter BM-8 manufactured by Topcon Corporation. The emission spectrum and emission peak wavelength were measured using a spectrum analyzer PMA-11 manufactured by Hamamatsu Photonics. Based on these, the external quantum efficiency with a luminance of around 1000 cd / m ² was calculated by the luminance conversion method.
Table 1 below shows the case where the external quantum efficiency is 15% or more: ◎: 10% or more and less than 15%; ◯, 8% or more and less than 10%; It was shown to.

(durability)
Each element, luminance at room temperature (20 ° C.) to continue applying to emit light a DC voltage to be 5000 cd / m ^2, luminance is used as an index of durability time taken until 4000 cd / m ² . Table 1 below shows ◎ when 700 hours or more, ◯ when 500 hours or more and less than 700 hours, Δ when 300 hours or more and less than 500 hours, and × when less than 300 hours.

(Examples 12 to 14, Comparative Examples 6 to 10)
In the preparation of device 1, device 9 was obtained by substituting the compounds described below. Further, the third layer compound (1-1) was the same as the device 9 except that the compound represented by the general formula (1) shown in Table 2 below and the above-mentioned comparative compounds (1) to (5) were replaced. Thus, elements of the examples and comparative examples were obtained.

(Examples 15 to 24, Comparative Examples 11 to 15)
In the preparation of the element 11, the element 15 was obtained by replacing the compound (ETL-1) in the fourth layer with the compound (1-3) of the present invention. In addition, each example was performed in the same manner as in the element 1 except that the compound (1-3) in the fourth layer was replaced with the compound represented by the general formula (1) shown in Table 3 below and the above-described comparative compound (5). And the element of the comparative example was obtained.

From Tables 1 to 3, it was found that an organic electroluminescence device having a low driving voltage and excellent durability can be obtained by using the charge transport material of the present invention.
Moreover, it turned out that the organic electroluminescent element using the charge transport material of the present invention tends to have high efficiency.
Note that the emission peak wavelengths of the organic electroluminescent devices prepared in Examples 1 to 24 were 510 to 530 nm.

In the case of a light-emitting device, a display device, and a lighting device, it is necessary to emit light with high brightness instantaneously through a high current density in each pixel portion, and the light-emitting element of the present invention is designed to increase the light emission efficiency in such a case. Therefore, it can be used advantageously.
In addition, the element of the present invention is excellent in durability and is suitable for a light emitting device, a display device, and a lighting device.

DESCRIPTION OF SYMBOLS 2 ... Substrate 3 ... Anode 4 ... Hole injection layer 5 ... Hole transport layer 6 ... Light emitting layer 7 ... Hole block layer 8 ... Electron transport layer 9 ...・ Cathode 10: Organic electroluminescent device (organic EL device)
DESCRIPTION OF SYMBOLS 11 ... Organic layer 12 ... Protective layer 14 ... Adhesive layer 16 ... Sealing container 20 ... Light-emitting device 30 ... Light scattering member 30A ... Light incident surface 30B ... Light Output surface 31 ... Transparent substrate 32 ... Fine particle 40 ... Illumination device

Claims

A charge transport material comprising a compound having a structure represented by the following general formula (1) and containing 6 to 19 monocyclic benzene rings.
General formula (1)

(In the general formula (1), R 111 to R 128 each represent a hydrogen atom or a substituent. At least one of R 111 to R 122 is a cyano group, provided that each of the three consecutive benzene rings has a cyano group. The benzene ring having a cyano group is not substituted with three or more benzene rings.
2. The charge transport material according to claim 1, wherein one or two of R 111 to R 128 in the general formula (1) are cyano groups.
3. The charge transport material according to claim 1, wherein the compound having the structure represented by the general formula (1) has a molecular weight of 500 to 1,000.
A substrate,
A pair of electrodes disposed on the substrate, including an anode and a cathode;
An organic layer disposed between the electrodes,
An organic electroluminescent device, wherein the organic layer contains a phosphorescent material and the charge transport material according to any one of claims 1 to 3.
5. The organic electric field according to claim 4, wherein the organic layer has a light emitting layer containing the phosphorescent light emitting material, and the light emitting layer contains a compound having a structure represented by the general formula (1). Light emitting element.
6. The light emitting layer includes a partial structure represented by a partial structure represented by the following general formula (3-A) as a compound having a structure represented by the general formula (1). The organic electroluminescent element of description.

(In the general formula (3-A), R 230 and R 231 are each independently substituted with a hydrogen atom or an aryl group (however, an alkyl group, a halogen atom, a cyano group, or an aryl group may be substituted. And at least one of R 230 and R 231 represents an aryl group, and one or two of R 211 to R 218 represent a cyano group, provided that not to have each a cyano group three consecutive benzene rings, among .R 211 ~ R 218 does not benzene ring is substituted with three or more benzene rings having cyano group, a cyano group In the case of two, there is no two cyano groups in one benzene ring.)
The light emitting layer contains a compound having a partial structure represented by the following partial structure group (1A) as a compound having a structure represented by the general formula (1). The organic electroluminescent element as described.
The organic layer has a light emitting layer containing the phosphorescent material and other organic layers,
The other organic layer disposed between the light emitting layer and the cathode contains a compound having a structure represented by the general formula (1). The organic electroluminescent element of description.
The compound which the other organic layer arrange | positioned between the said light emitting layer and the said cathode has the partial structure represented by the following partial structure group (1A) as a compound of the structure represented by the said General formula (1) The organic electroluminescent element according to claim 8, comprising:
The compound having a partial structure represented by the partial structure group (1A) is a chain structure in which one or more benzene rings are not substituted on one benzene ring. Organic electroluminescent device.
As the compound having the structure represented by the general formula (1), the partial structure represented by any one of the partial structure groups (1A-1), (1A-2), (1A-3), and (1A-7) The organic electroluminescent element according to claim 9 or 10, wherein the organic electroluminescent element comprises a compound having the following.
Containing at least one compound represented by the general formula (1) in the light emitting layer, and
The organic electroluminescent element according to claim 11, wherein the other organic layer arranged between the light emitting layer and the cathode contains at least one compound represented by the general formula (1).
13. The organic electroluminescent element according to claim 8, wherein an iridium (Ir) complex is used as the phosphorescent material in the light emitting layer.
The organic electroluminescence according to any one of claims 8 to 12, wherein an iridium (Ir) complex represented by the following general formula (E-1) is used as the phosphorescent material in the light emitting layer. element.
Formula (E-1)

In general formula (E-1), Z 1 and Z 2 each independently represents a carbon atom or a nitrogen atom. A 1 represents an atomic group that forms a 5- or 6-membered heterocycle with Z 1 and a nitrogen atom. B 1 represents an atomic group that forms a 5- or 6-membered ring with Z 2 and a carbon atom. Z 1 and Z 2 each independently represents a carbon atom or a nitrogen atom. (XY) represents a monoanionic bidentate ligand. n E1 represents an integer of 1 to 3.
A light-emitting device, display device, or illumination device comprising the organic electroluminescent element according to any one of claims 8 to 14.