JPWO2008153088A1 - Organic electroluminescence element and element material - Google Patents

Abstract

An object of the present invention is to produce a phosphorescent organic electroluminescence device capable of realizing an emission peak due to electroluminescence in a deep blue region of 440 nm or less, which is important for completing a full color display. is there. An object of the present invention is an organic electroluminescence element in which a light emitting layer or a plurality of organic compound thin layers including a light emitting layer is formed between a pair of electrodes, and has a phosphorescent electroluminescence emission peak having a wavelength of 440 nm or less. Further, it has a phosphorescent electroluminescence emission peak maximum in a deep blue region of 440 nm or less, and the emission color is the International Illumination Commission (CIE) color system and the y coordinate is less than 0.180. This is solved by an organic electroluminescence device.

Description

  The present invention relates to an organic electroluminescence device (electroluminescence device) having a phosphorescent electroluminescence emission peak with a wavelength of 440 nm or less, a novel electroluminescence device capable of completing a full color display, and a device material for the organic electroluminescence device. The organic electroluminescence device of the present invention is considered to be a device that is useful for realizing completion of a full-color display, for example.

In recent years, attention has been focused on application to display devices for high-performance flat color displays as applications of organic electroluminescence elements, but fluorescent materials that utilize light emission from excited singlets of luminescent molecules are mainly used as luminescent materials. In order to achieve higher efficiency, phosphorescent materials that use light emitted from excited triplets have been actively developed. However, in phosphorescent organic electroluminescence elements, it is important to create an element that realizes an emission peak due to electroluminescence in a deep blue region of 440 nm or less, which is important for completing a full-color display, and in a deep blue region of 440 nm or less. It is said that it is very difficult to create an element having a phosphorescent electroluminescence emission peak maximum and an emission color of the International Lighting Commission (CIE) color system with a y coordinate of less than 0.180. (For example, refer nonpatent literature 1).
Abstracts of “2006 Organic EL Symposium”, 7 pages (Polymer Society of Japan)

  An object of the present invention is to provide a phosphorescent organic electroluminescence device capable of realizing a light emission peak due to electroluminescence in a deep blue region of 440 nm or less, which is important for completing a full color display, and further 440 nm. An object of the present invention is to produce an element having a phosphorescent electroluminescence emission peak maximum in the following deep blue region and having an emission color of less than 0.180 in the CIE (International Commission on Illumination) color system.

  An object of the present invention is an organic electroluminescence element in which a light emitting layer or a plurality of organic compound thin layers including a light emitting layer is formed between a pair of electrodes, and has a phosphorescent electroluminescence emission peak having a wavelength of 440 nm or less. It is solved by the featured organic electroluminescent device.

  Accordingly, the first aspect of the present invention is an organic electroluminescence device in which a light emitting layer or a plurality of organic compound thin layers including a light emitting layer is formed between a pair of electrodes, and has a phosphorescent electroluminescence emission peak having a wavelength of 440 nm or less. It has an organic electroluminescent element characterized by having.

  The second aspect of the present invention has a phosphorescent electroluminescence emission peak maximum in a deep blue region of 440 nm or less, an emission color is an International Illumination Commission (CIE) color system, and a y coordinate is less than 0.180. The present invention relates to an organic electroluminescence element.

  The third aspect of the present invention relates to an organic electroluminescence device comprising one or more kinds of germanium compounds in a light emitting layer.

  In the fourth aspect of the present invention, the germanium compound has the general formula (1):

(In formula, L is 0-2 and k is an integer of 0-3.
R ^{1 to} R ⁶ may be the same or different and are an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, an aryl group, a heteroaryl group, an alkoxy group, or an aryloxy group. In these groups, any hydrogen atom is a halogen atom, alkyl group, cycloalkyl group, alkenyl group, aryl group, aralkyl group, alkoxy group, aryloxy group, alkyl mercapto group, aryl mercapto group or organosilyl group. It may be replaced with.
Further, R ^{1 to} R ⁶ may be bonded to each other to form a ring, and the bonding group that connects the rings is a single bond, an ether bond, a thioether bond, an alkylene group, an oxaalkylene group, or a thiaalkylene. It is a group.
X is an alkyl group, cycloalkyl group, alkenyl group, aryl group, aralkyl group, alkoxy group, aryloxy group, alkyl mercapto group, aryl mercapto group or amino group having a substituent. )
It is related with the organic electroluminescent element which is a germanium compound shown by these.

  In the fifth aspect of the present invention, the germanium compound has the general formula (1a):

(In the formula, k, X and R ^{1 to} R ⁶ are as defined above.)
It is related with the organic electroluminescent element which is a germanium compound shown by these.

  In the sixth aspect of the present invention, the germanium compound has the following formula (2):

(In the formula, l is an integer of 0 to 2, m is an integer of 1 to 3, n is an integer of 1 to 3, and k is as defined above. Ar may be the same or different, and aryl. These groups are groups or heteroaryl groups in which any hydrogen atom is a halogen atom, alkyl group, cycloalkyl group, alkenyl group, aryl group, aralkyl group, alkoxy group, aryloxy group, alkyl mercapto group, aryl It may be substituted with a mercapto group or an organosilyl group, and different Ars may be substituted with the same Ge atom, but in this case, the total number of different Ar groups is equal to m. Ar may be bonded via a single bond, an ether bond, a thioether bond, an alkylene group, an oxaalkylene group or a thiaalkylene group, and R is an alkyl group, Black alkyl group, an alkenyl group, an aralkyl group, .X an alkoxy group or an aryloxy group is a germanium compound represented by the same meanings as defined above.), An organic electroluminescent device.

  In the seventh aspect of the present invention, the germanium compound is (2a):

(Wherein, k, m, n, X, Ar and R are as defined above.)
It is related with the organic electroluminescent element which is a germanium compound shown by these.

  In the eighth aspect of the present invention, the germanium compound has the general formula (2b):

(Wherein, k, X and Ar are as defined above.)
It is related with the organic electroluminescent element which is a germanium compound shown by these.

In the ninth invention, the germanium compound has the formulas (1c) to (1g):

It is related with the organic electroluminescent element which is at least 1 sort (s) of compounds selected from the compound group shown by these.

  The tenth aspect of the present invention relates to an organic electroluminescence device in which the light emitting layer contains a plurality of types of germanium compounds.

  In an eleventh aspect of the present invention, the light emitting layer has a single type or a plurality of types having different substituent configurations:

(In the formula, L represents a nitrogen-containing heterocyclic carbene ligand. Y represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or a heterocyclic group. Or a plurality of hydrogen atoms may be substituted with halogen atoms, alkyl groups, cycloalkyl groups, alkenyl groups, aryl groups, aralkyl groups, alkoxy groups, aryloxy groups, dialkylamino groups, carboalkyl groups or carboaryl groups. Also, multiple hydrogen atoms on the carbon atom of Y are substituted with an alkyl group, alkenyl group, aryl group, aralkyl group, alkoxy group, aryloxy group, dialkylamino group, carboalkyl group or carboaryl group. And the adjacent groups may be bonded to form a ring.) Direct and Russia on the luminescence element.

  The twelfth aspect of the present invention includes a hole transport layer, wherein the hole transport layer is a single type or a plurality of types having different substituent structures:

(Wherein Z is a single or plural alkyl group, cycloalkyl group, aryl group, aralkyl group or heterocyclic group. Note that one or plural hydrogen atoms on the carbon atom of Z are a halogen atom, An alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a dialkylamino group, a carboalkyl group, a carboaryl group, or an organosilyl group. The present invention relates to an organic electroluminescence device containing a compound.

  According to the first, third, and fourth aspects of the present invention, an organic electroluminescence element (electroluminescence element) having a phosphorescent electroluminescence emission peak with a wavelength of 440 nm or less and an element material for the organic electroluminescence element are obtained. The organic electroluminescence device of the present invention is considered to be a device that is useful for realizing completion of a full-color display, for example.

  According to the second and sixth aspects of the present invention, a phosphorescent electroluminescence emission peak has a maximum in a deep blue region having a wavelength of 440 nm or less, which is important for completing a full color display, and the emission color is a CIE (International Commission on Illumination) table. It is possible to realize an organic electroluminescence element having a color system with a y coordinate of less than 0.180.

2 is an EL spectrum of the organic electroluminescence device of Example 1. 2 is an EL spectrum (enlarged) of the organic electroluminescence element of Example 1. Examples 1, 2 and 8 are the structures of the organic electroluminescence elements, 1 is a glass substrate, 2 is an ITO transparent electrode, 3 is a hole transport layer, 4 is a light emitting layer, 5 is a hole block layer, and 6 is an electron transport layer. , 7 are aluminum electrodes. 2 is an EL spectrum of the organic electroluminescence device of Example 2. 10 is an EL spectrum of the organic electroluminescence device of Example 8.

  The organic electroluminescence device of the present invention is an organic electroluminescence device in which a light emitting layer or a plurality of organic compound thin layers including a light emitting layer is formed between a pair of electrodes, and has a phosphorescent electroluminescence emission peak having a wavelength of 440 nm or less. It is characterized by having.

  The germanium compound contained in this organic electroluminescence device has the general formula (1):

(In formula, L is 0-2, Preferably it is 1 or 2, and k is an integer of 0-3.
R ^{1 to} R ⁶ may be the same or different and are an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, an aryl group, a heteroaryl group, an alkoxy group, or an aryloxy group. In these groups, any hydrogen atom is a halogen atom, alkyl group, cycloalkyl group, alkenyl group, aryl group, aralkyl group, alkoxy group, aryloxy group, alkyl mercapto group, aryl mercapto group or organosilyl group. It may be replaced with.
Further, R ^{1 to} R ⁶ may be bonded to each other to form a ring, and the bonding group that connects the rings is a single bond, an ether bond, a thioether bond, an alkylene group, an oxaalkylene group, or a thiaalkylene. It is a group.
X is an alkyl group, cycloalkyl group, alkenyl group, aryl group, aralkyl group, alkoxy group, aryloxy group, alkyl mercapto group, aryl mercapto group or amino group having a substituent. )
It is a germanium compound shown by these.

  Preferably, general formula (1a):

(In the formula, k, X and R ^{1 to} R ⁶ are as defined above.)
An organic electroluminescence device, more preferably a general formula (1b)

(In the formula, k and X are as defined above, Ar ¹ and Ar ² may be the same or different, and are an aryl group or a heteroaryl group. The aryl group is an arbitrary hydrogen atom. May be substituted with a halogen atom, alkyl group, cycloalkyl group, alkenyl group, aryl group, aralkyl group, alkoxy group, aryloxy group, alkyl mercapto group or aryl mercapto group.
Further, Ar ¹ and Ar ² may be bonded to each other to form a ring, and the bonding group that connects the ring is an ether group, a thioether group, an alkylene group, an oxaalkylene group, or a thiaalkylene group. . )
The germanium compound shown by is used. In addition, you may use these germanium compounds individually or in mixture of 2 or more types.

  In the general formula (1), L is 0 to 2, preferably 1 or 2, and k is an integer of 0 to 3. When L is 1, the compound of the general formula (1a) is obtained.

R ^{1 to} R ⁶ may be the same or different and are an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, an aryl group, a heteroaryl group, an alkoxy group, or an aryloxy group.

  As said alkyl group, a C1-C20, especially C1-C12 alkyl group is preferable, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, Nonyl group, decyl group, undecyl group, dodecyl group, etc. are mentioned. These substituents include isomers thereof.

  The cycloalkyl group is preferably a cycloalkyl group having 5 to 8 carbon atoms, and examples thereof include a cyclopentyl group, a cyclohexyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group.

  The alkenyl group is preferably an alkenyl group having 2 to 20 carbon atoms, particularly 2 to 12 carbon atoms, such as vinyl group, propenyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, A decenyl group, an undecenyl group, a dodecenyl group, etc. are mentioned. These substituents include isomers thereof.

  The aralkyl group is preferably an aralkyl group having 7 to 20 carbon atoms, and examples thereof include a benzyl group, a naphthylmethyl group, an indenylmethyl group, and a biphenylmethyl group.

  The aryl group is preferably an aryl group having 6 to 12 carbon atoms, such as a phenyl group, a tolyl group (and its isomer), a xylyl group (and its isomer), a naphthyl group (and its isomer), and dimethyl. A naphthyl group (and its isomer) and the like.

  The heteroaryl preferably has 4 to 10 carbon atoms, and includes a furyl group, a thiophenyl group, a pyrrolyl group, an imidazolyl group, an oxazolyl group, a pyridyl group, a thiazolyl group, an indolyl group, a quinolyl group, an isoquinolyl group, a quinazolyl group, and a quinoxalyl group. Groups and the like.

  The alkoxy group is preferably an alkoxy group having 1 to 10 carbon atoms, such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentanoxy group, a hexanoxy group, a heptanoxy group, an octanoxy group, a nonanoxy group, and a decanoxy group. Can be mentioned. These substituents include isomers thereof.

  The aryloxy group is preferably an aryloxy group having 6 to 14 carbon atoms, and examples thereof include a phenoxy group, a triloxy group, a xylyloxy group, a naphthoxy group, and a dimethylnaphthoxy group. These substituents include isomers thereof.

In addition, in R ^{1 to} R ⁶ represented by the general formula (1), any hydrogen atom is a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, or an alkyl group. It may be substituted with a mercapto group, an aryl mercapto group or an organosilyl group.

  As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned, for example.

An alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxy group and an aryloxy group have the same meanings as those described for R ^{1 to} R ⁶ .

  The alkyl mercapto group is preferably an alkyl mercapto group having 1 to 6 carbon atoms, and examples thereof include a methyl mercapto group, an ethyl mercapto group, a propyl mercapto group, a butyl mercapto group, a pentyl mercapto group, and a hexyl mercapto group. These substituents include isomers thereof.

  The aryl mercapto group is preferably an aryl mercapto group having 6 to 14 carbon atoms, and examples thereof include a phenyl mercapto group, a tolyl mercapto group, a xylyl mercapto group, and a naphthyl mercapto group. These substituents include isomers thereof.

  The organosilyl group is preferably an organosilyl group having 3 to 18 carbon atoms, for example, trimethylsilyl group, dimethylethylsilyl group, triethylsilyl group, tripropylsilyl group, tributylsilyl group, butyldimethylsilyl group, phenyldimethylsilyl group. Group and naphthyldimethylsilyl group. These substituents include isomers thereof.

R ^{1 to} R ⁶ may be bonded to each other to form a ring, and the bonding group that connects the rings is a single bond (a state in which R ^{1 to} R ⁶ are directly bonded), ether Bond (directly R ^{1 to} R ⁶ are bonded via oxygen), thioether bond (direct R ^{1 to} R ⁶ bonded via sulfur), alkylene group, oxaalkylene group or thiaalkylene It is a group.

  As said alkylene group, a C1-C4 alkylene group is preferable, For example, a methylene group, ethylene group, a propylene group, and a butylene group are mentioned.

  The oxaalkylene group is preferably an oxaalkylene group having 1 to 5 carbon atoms, an oxamethylene group, an oxapropylene group, an oxabutylene group, an oxapentamethylene group, an oxahexamethylene group, a dioxamethylene group, a dioxapropylene group, Examples include a dioxabutylene group, a dioxapentamethylene group, and a dioxahexamethylene group. These substituents include isomers thereof.

  The thiaalkylene group is preferably a thiaalkylene group having 1 to 5 carbon atoms, a thiamethylene group, a thiapropylene group, a thiabutylene group, a thiapentamethylene group, a thiahexamethylene group, a dithiamethylene group, a dithiapropylene group, a dithiabutylene group, a dithiaethylene group. Examples include a thiapentamethylene group and a dithiahexamethylene group. These substituents include isomers thereof.

X is an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, an alkyl mercapto group, an aryl mercapto group, or an amino group having a substituent. , An alkenyl group, an aryl group, an aralkyl group, an alkoxy group and an aryloxy group have the same meanings as those described for R ^{1 to} R ⁶ .

  The alkyl mercapto group is preferably an alkyl mercapto group having 1 to 6 carbon atoms, and examples thereof include a methyl mercapto group, an ethyl mercapto group, a propyl mercapto group, a butyl mercapto group, a pentyl mercapto group, and a hexyl mercapto group. These substituents include isomers thereof.

  The aryl mercapto group is preferably an aryl mercapto group having 6 to 14 carbon atoms, and examples thereof include a phenyl mercapto group, a tolyl mercapto group, a xylyl mercapto group, and a naphthyl mercapto group. These substituents include isomers thereof.

  The substituted amino group is preferably a substituted amino group having 1 to 14 carbon atoms, for example, methylamino group, ethylamino group, propylamino group, butylamino group, dimethylamino group, diethylamino group, dipropylamino group. Group, phenylamino group, tolylamino group, xylylamino group, naphthylamino group, phenylmethylamino group, phenylethylamino group, diphenylamino group, ditolylamino group, and dixylylamino group. These substituents include isomers thereof.

When R ^{1 to} R ⁶ are all aryl groups or heteroaryl groups, the compound is represented by the general formula (1b). In the general formula (1b), Ar ¹ and Ar ² are the same or They may be different and are aryl groups or heteroaryl groups. In the aryl group, any hydrogen atom is substituted with a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, an alkyl mercapto group or an aryl mercapto group. May be. Further, Ar ¹ and Ar ² may be bonded to each other to form a ring, and the bonding group that connects the ring is an ether group, a thioether group, an alkylene group, an oxaalkylene group, or a thiaalkylene group. . These are synonymous with the groups listed for R ^{1 to} R ⁶ .

  Specific examples of the germanium compound of the present invention include, for example, general formulas (1c) to (1g).

The germanium compound shown by is used suitably. It is desirable that a plurality of these germanium compounds are contained in the light emitting layer.

The germanium compound of the present invention is a compound obtained, for example, by introducing a substituent corresponding to the position of a halogen atom using a halogenated germanium compound as a starting material (see, for example, Non-Patent Document 2).
Nihon Chemical Journal, Vol.84, 1963, p.272

  Next, a preferable organic electroluminescence device of the present invention is an organic electroluminescence device in which a light emitting layer or a plurality of organic compound thin layers including a light emitting layer is formed between a pair of electrodes, and a phosphor layer in a deep blue region of 440 nm or less. It has a photoelectroluminescence emission peak maximum and is characterized in that the emission color is (International Commission on Illumination (CIE) color system and the y coordinate is less than 0.180.

  The element has a single light emitting layer or a plurality of types of general formulas (2) having different substituent structures:

(Wherein, l is an integer of 0 to 2, m is an integer of 1 to 3, n is an integer of 1 to 3, and k is an integer of 0 to 3. Ar is an aryl group or a heteroaryl group, The hydrogen atoms may be the same or different, and any hydrogen atom may be a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, an alkyl mercapto group, an aryl mercapto group, or a substituent. It may be substituted with an amino group or an organosilyl group, and different Ars may be substituted with the same Ge atom, but in this case, the total number of different Ar groups is equal to m. Ar may be bonded via a single bond, an ether bond, a thioether bond, an alkylene group, an oxaalkylene group or a thiaalkylene group. A cycloalkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, an alkoxy group, or an aryloxy group, where X is an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, an alkyl mercapto group. Or an aryl mercapto group).

  When Ar is an aryl group, those having 6 to 14 carbon atoms are preferred, and examples thereof include a phenyl group, a naphthyl group, a phenanthryl group, and an anthracenyl group.

  The Ar is preferably a heteroaryl group having 4 to 10 carbon atoms, such as furyl, thiophenyl, pyrrolyl, imidazolyl, oxazolyl, pyridyl, thiazolyl, indolyl, quinolyl, isoquinolyl, quinazolyl. Group, quinoxalyl group and the like.

  Arbitrary hydrogen atom of the above aryl group or heteroaryl group is a halogen atom, alkyl group, cycloalkyl group, alkenyl group, aryl group, aralkyl group, alkoxy group, aryloxy group, alkyl mercapto group, aryl mercapto group, substituent May be substituted with an amino group or an organosilyl group having a hydrogen atom, and adjacent Ar may be directly bonded via an ether bond or a thioether bond, or an alkylene group, an oxaalkylene group or a thiaalkylene group.

  Amino having the halogen atom, the alkyl group, the cycloalkyl group, the alkenyl group, the aryl group, the aralkyl group, the alkoxy group, the aryloxy group, the alkyl mercapto group, the aryl mercapto group, the substituent The group, the organosilyl group, the alkylene group, the oxaalkylene group, and the thiaalkylene group are as defined above.

  The alkyl group, cycloalkyl group, alkenyl group, aryl group, aralkyl group, alkoxy group, aryloxy group, alkyl mercapto group and aryl mercapto group, and the alkylene group, oxaalkylene group and thiaalkylene group connecting adjacent Ar are Further, the hydrogen atom bonded to the carbon atom is a halogen atom, alkyl group, alkenyl group, aryl group, alkoxy group, aryloxy group, alkyl mercapto group, aryl mercapto group, nitro group, cyano group or dialkylamino group And the like may be further substituted. Examples of these substituents are the same as those defined as the substituent for Ar.

  R is an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, an alkoxy group, or an aryloxy group. These are the same as those defined as the substituent for Ar.

  X is as defined above.

  The organic germanium compound represented by the formula (1) or (2) contained in the organic electroluminescence device of the present invention is represented by the formula (6), (7) or (8) according to the description of Non-Patent Document 1, for example. It can synthesize | combine by making the organometallic compound and organic germanium chloride (Formula (5)) react (for example, refer nonpatent literature 2).

(Wherein j is an integer of 0 to 3. Ar is as defined above.)

(Wherein Ar is as defined above, M is Li or MgY, where Y is chlorine, bromine or iodine.)

(Wherein R is as defined above, M is Li or MgY, where Y is chlorine, bromine or iodine.)

(Wherein X is as defined above, 1 is an integer of 2 to 3, k is an integer of 0 to 3, M is Li or MgY, where Y is as defined above.)

  Preferred examples of the compound include the compounds (1c) to (1g) described above.

  The organic electroluminescence device of the present invention is an organic electroluminescence device in which a light emitting layer or a plurality of organic compound thin layers including a light emitting layer is formed between a pair of electrodes, and has a phosphorescent electroluminescence emission peak having a wavelength of 440 nm or less. Preferably, it has a phosphorescent electroluminescence emission peak maximum in a deep blue region of 440 nm or less, the emission color is the International Illumination Commission (CIE) color system, and the y coordinate is 0. More preferably, the organic electroluminescence device includes one or a plurality of germanium compounds in the light emitting layer.

  The organic electroluminescent device of the present invention is an organic electroluminescent device having a single-layer or multi-layer organic compound layer between a pair of electrodes, and the light-emitting layer is a compound represented by the formula (1) or (2). Among them, a single type or a plurality of types having different substituent structures are contained.

  The organic compound layer is a light emitting layer, an electron injection layer, or a hole transport layer, and one or a plurality of germanium compounds represented by the formula (1), or the compound and the compound group represented by the formula (2) are In addition to the light emitting layer, it may be contained in the electron injection layer and the hole transport layer.

  The addition amount of the germanium compound represented by the formula (1) or (2) to the light emitting layer and other organic compound layers is preferably 2 to 98% by mass.

  The organic electroluminescence device of the present invention can be used in combination with a light emitting material, other doping materials, a hole injection material and an electron injection material. Furthermore, each of the hole injection layer, the light emitting layer, and the electron injection layer may be formed with a layer configuration of two or more layers. In that case, in the case of a hole injection layer, the layer that injects holes from the electrode is a hole injection layer, and the layer that receives holes from the hole injection layer and transports holes to the light emitting layer is a hole transport layer. Call. Similarly, in the case of an electron injection layer, a layer that injects electrons from an electrode is referred to as an electron injection layer, and a layer that receives electrons from the electron injection layer and transports electrons to a light emitting layer is referred to as an electron transport layer. Each of these layers is selected and used depending on factors such as the energy level of the material, heat resistance, adhesion with the organic compound layer or the metal electrode.

  As a material used for the light emitting layer together with the germanium compound represented by the general formula (1) or (2), in order to obtain phosphorescence, various iridium and platinum having a phosphorescent photoluminescence peak at a wavelength of 440 nm or less. It is essential to add a phosphorescent complex dye having a central metal such as gold, osmium and ruthenium. Examples of these include complexes as shown in known literature (see, for example, Patent Document 1, Non-Patent Documents 3 and 4).

International Publication WO2006-80515 Pamphlet Abstracts of “2006 Organic EL Symposium”, 7 pages (Polymer Society of Japan) Inorganic Chemistry, 44, 7992 (2005)

  Of these, the compound group represented by the following formula described in Patent Document 1 is preferably used.

(In the formula, L represents a nitrogen-containing heterocyclic carbene ligand. Y represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or a heterocyclic group. Or a plurality of hydrogen atoms may be substituted with halogen atoms, alkyl groups, cycloalkyl groups, alkenyl groups, aryl groups, aralkyl groups, alkoxy groups, aryloxy groups, dialkylamino groups, carboalkyl groups, or carboaryl groups. Also, a plurality of hydrogen atoms on the carbon atom of Y are substituted with an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a dialkylamino group, a carboalkyl group or a carboaryl group. When adjacent to each other, adjacent groups may be bonded to form a ring.)

  In addition to these, as the light emitting material or host material that can be added to the light emitting layer, various carbazole derivatives, condensed polycyclic aromatics (anthracene, naphthalene, phenanthrene, pyrene, tetracene, pentacene, coronene, chrysene, fluorescein, perylene, rubrene, and their Derivatives, etc.), phthaloperylene, naphthaloperylene, perinone, phthaloperinone, naphthaloperinone, diphenylbutadiene, tetraphenylbutadiene, coumarin, oxadiazole, aldazine, bisbenzoxazoline, bisstyryl, pyrazine, cyclopentadiene, quinoline metal complex, aminoquinoline metal complex, Benzoquinoline metal complex, quinolyl acetylene metal complex, quinoxaly acetylene metal complex, quinazolyl acetylene metal complex, imine, diphenylethylene, Sulfonyl anthracene, diaminocarbazole, pyran, thiopyran, polymethine, merocyanine, imidazole chelated oxinoid compounds, quinacridone, rubrene, stilbene derivatives and fluorescent dyes.

  Among known hole injection materials that can be used in the organic electroluminescence device of the present invention, more effective hole injection materials are aromatic tertiary amine derivatives or phthalocyanine derivatives.

  Examples of the aromatic tertiary amine derivatives include triphenylamine, tolylamine, tolyldiphenylamine, N, N′-diphenyl-N, N ′-(3-methylphenyl) -1,1′-biphenyl-4, 4′-diamine (hereinafter referred to as TPD), N, N, N ′, N ′-(4-methylphenyl) -1,1′-phenyl-4,4′-diamine, N, N, N ′, N ′-(4-methylphenyl) -1,1′-biphenyl-4,4′-diamine, N, N′-diphenyl-N, N′-dinaphthyl-1,1′-biphenyl-4,4′- Diamine, N, N ′-(methylphenyl) -N, N ′-(4-n-butylphenyl) -phenanthrene-9,10-diamine, 1,1-bis [4- (di-4-tolylamino) phenyl ] Cyclohexane etc. or this It is a oligomer or polymer having an aromatic tertiary amine skeletons, though not particularly limited thereto.

Examples of the phthalocyanine (Pc) derivative include H ₂ Pc, CuPc, CoPc, NiPc, ZnPc, PdPc, FePc, MnPc, ClAlPc, ClGaPc, ClInPc, ClSnPc, Cl ₂ SiPc, (HO) AlPc, (HO) GaPc. , Phthalocyanine derivatives or naphthalocyanine derivatives such as VOPc, TiOPc, MoOPc, and GaPc-O-GaPc, but are not limited thereto.

  A specific embodiment of the triphenylene derivative is represented by the following formula.

  In the formula, Z is a single or plural alkyl group, cycloalkyl group, aryl group, aralkyl group or heterocyclic group. Note that one or more hydrogen atoms on the carbon atom of Z are a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a dialkylamino group, a carboalkyl group, It may be substituted with a carboaryl group or an organosilyl group. Examples of these substituents are the same as those defined as the substituent for Ar.

  In the organic electroluminescence device of the present invention, a more effective known electron injection material is a metal complex compound or a nitrogen-containing five-membered ring derivative.

Examples of the metal complex compound include 8-hydroxyquinolinate lithium, bis (8-hydroxyquinolinato) zinc, bis (8-hydroxyquinolinato) copper, bis (8-hydroxyquinolinato) manganese, and tris. (8-hydroxyquinolinato) aluminum (hereinafter referred to as Alq ₃ ), tris (2-methyl-8-hydroxyquinolinato) aluminum, tris (8-hydroxyquinolinato) gallium, bis (10-hydroxy) Benzo [h] quinolinato) beryllium, bis (10-hydroxybenzo [h] quinolinato) zinc, bis (2-methyl-8-quinolinato) chlorogallium, bis (2-methyl-8-quinolinato) (o-cresolate) gallium Bis (2-methyl-8-quinolinato) (1-naphtholate) Examples thereof include, but are not limited to, aluminum and bis (2-methyl-8-quinolinato) (2-naphtholate) gallium.

  As the nitrogen-containing five-membered ring derivative, for example, an oxazole, thiazole, oxadiazole, thiadiazole or triazole derivative is preferable. Specifically, 2,5-bis (1-phenyl) -1,3,4-oxazole and dimethyl POPOP (where POPOP is 1,4-bis (5-phenyloxazol-2-yl) benzene). ), 2,5-bis (1-phenyl) -1,3,4-thiazole, 2,5-bis (1-phenyl) -1,3,4-oxadiazole, 2- (4′-tert- Butylphenyl) -5- (4 "-biphenyl) -1,3,4-oxadiazole, 2,5-bis (1-naphthyl) -1,3,4-oxadiazole, 1,4-bis [ 2- (5-phenyloxadiazolyl)] benzene, 1,4-bis [2- (5-phenyloxadiazolyl) -4-tert-butylbenzene], 2- (4′-tert-butylphenyl)- 5- (4 ″ -biphenyl) -1,3,4 Thiadiazole, 2,5-bis (1-naphthyl) -1,3,4-thiadiazole, 1,4-bis [2- (5-phenylthiadiazolyl)] benzene, 2- (4′-tert-butylphenyl) ) -5- (4 ″ -biphenyl) -1,3,4-triazole, 3- (4-biphenylyl) -4-phenyl-5-tert-butylphenyl-1,2,4-triazole, 2,5 Examples include -bis (1-naphthyl) -1,3,4-triazole and 1,4-bis [2- (5-phenyltriazolyl)] benzene, but are not limited thereto.

  In the organic electroluminescence device of the present invention, an inorganic compound layer may be provided between the light emitting layer and the electrode in order to improve the charge injection property.

Examples of the inorganic compound layer include fluorides and oxides of alkali metals or alkaline earth metals such as LiF, Li ₂ O, RaO, SrO, BaF ₂ and SrF ₂ .

  As the conductive material used for the anode of the organic electroluminescence device of the present invention, a material having a work function larger than 4 eV is suitable. For example, carbon atom, aluminum, vanadium, iron, cobalt, nickel, tungsten, silver , Gold, platinum, palladium and their alloys, ITO (material in which indium oxide is added 5-10% tin oxide) substrate, metal oxides such as tin oxide and indium oxide used for NESA substrate, polythiophene, polypyrrole, etc. The organic conductive resin can be used.

  As the conductive material used for the cathode, those having a work function smaller than 4 eV are suitable. For example, magnesium, calcium, tin, lead, titanium, yttrium, lithium, ruthenium, manganese, aluminum, and alloys thereof Is used. Here, examples of the alloy include magnesium / silver, magnesium / indium, and lithium / aluminum. The ratio of the alloy is not particularly limited and is controlled by the temperature of the vapor deposition source, the atmosphere, the degree of vacuum, and the like.

  Note that the anode and the cathode may be formed of a layer structure of two or more layers if necessary.

  As for the organic electroluminescent element of this invention, it is desirable for at least one surface to be transparent in the light emission wavelength range of an element, and it is desirable that a board | substrate is also transparent.

  The transparent electrode is obtained by using the conductive material described above and setting so as to ensure a predetermined translucency by a method such as vapor deposition or sputtering.

  The electrode on the light emitting surface preferably has a light transmittance of 10% or more.

  The substrate is not particularly limited as long as it has mechanical and thermal strength and has transparency, and examples thereof include a glass substrate and a transparent resin film.

  Examples of the transparent resin film include polyethylene, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polypropylene, polystyrene, polymethyl methacrylate, polyvinyl chloride, polyvinyl alcohol, polyvinyl butyral, nylon, poly Ether ether ketone, polysulfone, polyether sulfone, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, polyvinyl fluoride, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polychlorotri Fluoroethylene, polyvinylidene fluoride, polyester, polycarbonate, polyurethane, polyimide, polyetherimide, polyimide and polypropylene Ren, and the like.

  In order to improve stability to temperature, humidity, atmosphere, etc., the organic electroluminescent device of the present invention may be provided with a protective layer on the surface of the device or protect the entire device with silicon oil or resin, for example. it can.

  In addition, the formation of each layer of the organic electroluminescence element employs, for example, either a dry film formation method such as vacuum deposition, sputtering, plasma or ion plating, or a wet film formation method such as spin coating, dipping or flow coating. can do. The film thickness is not particularly limited, but the film thickness is preferably in the range of 5 nm to 10 μm, more preferably 10 nm to 0.2 μm.

  In the case of the wet film forming method, the thin film can be prepared by dissolving or dispersing the compound represented by the formula (1) on each layer in a solvent such as ethanol, chloroform, tetrahydrofuran, or dioxane.

As the dry film forming method, vacuum vapor deposition is preferable, and using the vacuum vapor deposition apparatus, the degree of vacuum is 2 × 10 ⁻³ Pa or less, the substrate temperature is set to room temperature, and the above formula (1) or A thin film can be prepared by heating an organic germanium compound having an aromatic substituent represented by (1a), (2) or (2a) and evaporating the material. At this time, in order to control the temperature of the vapor deposition source, a thermocouple or a non-contact infrared thermometer brought into contact with the vapor deposition cell is preferably used. A vapor deposition film thickness meter is preferably used to control the vapor deposition amount.

  As a vapor deposition film thickness meter, a quartz crystal unit installed opposite to a vapor deposition source is used, and the weight of the vapor deposition film adhering to the surface of the quartz crystal unit is measured from a change in the oscillation frequency of the crystal unit. From the above, the type in which the film thickness is obtained in real time is preferably used.

  Co-evaporation of the compound represented by the general formula (1) or (2) and the light-emitting material or other host material can be performed by using an evaporation source for each and controlling the temperature independently.

  Here, any organic thin film layer is made of polystyrene, polycarbonate, polyacrylate, polyester, polyamide, polyurethane, polysulfone, polymethyl methacrylate, polymethyl acrylate, cellulose, etc. for improving film formability and preventing pinholes in the film. Insulating resin or copolymer thereof, photoconductive resin such as poly-N-vinylcarbazole or polysilane, resin such as conductive resin such as polythiophene or polypyrrole, or antioxidant, ultraviolet absorber or plasticizer Additives can be used.

  The organic electroluminescent element of the present invention is, for example, a flat light emitter such as a wall-mounted television or a flat panel display of a mobile phone, a backlight of a copying machine, a printer or a liquid crystal display, a light source such as an instrument, a display board, or a marker lamp Available to:

  EXAMPLES The present invention will be specifically described below with reference to examples, but the scope of the present invention is not limited to these examples. Note that the chromaticity coordinates were obtained according to JIS standard Z8701. Further, the efficiency of the current related to light emission of this element was obtained by the following formula 1.

(Formula 1)
Current efficiency = (luminescence brightness per unit area) / (current density per unit area)

Example 1 (phosphorescent complex (Au (IPr) (4F-PE) [(4-fluorophenylethynyl) [1,3-bis (2,6-diisopropylphenyl) imidazol-2-ylidene] gold]) (complex 1 ) Preparation of organic electroluminescent device containing organic light emitting layer as guest)
Using a glass with an indium tin oxide (hereinafter abbreviated as ITO) film manufactured by ECH as a transparent electrode substrate, a vacuum of 2 × 10 ⁻³ Pa or less is formed on the substrate using a vacuum deposition apparatus (manufactured by ULVAC Kiko). The hole transport layer 3 made of (1,1-bis [4- (di-4-tolylamino) phenyl] cyclohexane (hereinafter abbreviated as TPAC) is formed to a thickness of 40 nm, 2-methyl-1,4-bis (tri Phosphorescent complex (Au (IPr) (4F-PE) [((mass)) in a host material composed of (phenylgermyl) benzene (10% by mass) and 1,3-bis (triphenylgermyl) benzene (90% by mass). The light-emitting layer 4 containing 5.0% by weight of 4-fluorophenylethynyl) [1,3-bis (2,6-diisopropylphenyl) imidazol-2-ylidene] gold] (gold complex 1) has a thickness of 30 nm, 3- The hole blocking layer 5 made of 4-biphenylyl) -4-phenyl-5-tertiarybutylphenyl-1,2,4-triazole is 30 nm, and the electron transport layer 6 made of lithium fluoride (hereinafter abbreviated as LiF) is 0. An organic electroluminescence device was manufactured by sequentially vacuum depositing aluminum (Al) at a thickness of 0.5 nm and an electrode 7 of 100 nm (FIG. 1).

  The vacuum deposition was performed by charging the raw material in a crucible placed opposite to the substrate and heating the raw material together with the crucible.

When the ITO electrode 2 of the device is used as a positive electrode and the Al electrode 7 is used as a negative electrode and the voltage between the electrodes is increased, the device starts to emit light from the vicinity of +7 V, and is clearly visibly visible at +23 V at 472 cd / m ² . Emitted light. The current efficiency for light emission of this element was 1.57 cd / A at + 23V.

Example 2 (Organic Light-Emitting Layer Using Phosphorescent Complex (Ir (dpbic) ₃ [Tris (N, N′-diphenylbenzimidazoline-2-ylidene) iridium] (Complex 2): Complex described in Non-Patent Document 1)] Of organic electroluminescence device
Using a glass with ITO coating as a transparent electrode substrate, using a vacuum deposition apparatus (manufactured by ULVAC Kiko), a hole transport layer 3 made of TPAC is formed on the same substrate with a vacuum degree of 2 × 10 ⁻³ Pa or less. Phosphorescence in a host material composed of 40 nm, 2-methyl-1,4-bis (triphenylgermyl) benzene (10% by mass) and 1,3-bis (triphenylgermyl) benzene (90% by mass) A hole blocking layer comprising a light emitting layer 4 containing 5.0% by mass of complex (Ir (dpbic) ₃ [tris (N, N′-diphenylbenzimidazoline-2-ylidene) iridium] (complex 2) having a thickness of 30 nm and TAZ. 5 is 30 nm, an electron transport layer 6 made of lithium fluoride (hereinafter abbreviated as LiF) is 0.5 nm, and aluminum (Al) is deposited as an electrode 100 nm in order by vacuum vapor deposition. The Minessensu device was fabricated (Fig. 1).

  The vacuum deposition was performed by charging the raw material in a crucible placed opposite to the substrate and heating the raw material together with the crucible.

When the ITO electrode 2 of the device is used as a positive electrode and the Al electrode 7 is used as a negative electrode and the voltage between the electrodes is increased, the device starts to emit light that is clearly visible to the naked eye from around +9 V, and at 466 cd / m ² at +27 V. Emitted light. The current efficiency for light emission of this device was 1.47 cd / A at + 21V.

Example 3 (Synthesis of 2-methyl-1,4-bis (triphenylgermyl) benzene)
In a 25 ml Schlenk tube, 203 μl (1.5 mmol) of 2,5-dibromotoluene and 12 ml of tetrahydrofuran were mixed in an argon atmosphere, and the solution was cooled to −78 ° C. with dry ice (solid oxygen dioxide) -ethanol and t-butyllithium. Of pentane (f = 1.48) was added dropwise. After the dropwise addition, the reaction solution was stirred for 1 hour while maintaining the reaction temperature at -78 ° C., and 1.12 g (3.3 mmol) of triphenyl germanium chloride was added. The mixture was stirred for 10 minutes while maintaining at -78 ° C, and then reacted at 0 ° C for 2 hours in an ice bath. After completion of the reaction, a suspension obtained by adding 40 ml of water and 80 ml of methylene chloride to the reaction solution was filtered. The obtained filtrate was washed with 20 ml of water twice and 20 ml of ethanol twice, and then dried under reduced pressure to give 2-methyl-1,4-bis (triphenylgermyl) benzene as a white solid. 86 g was obtained (82% yield).

Example 4 (Synthesis of 2,5-dimethyl-1,4-bis (triphenylgermyl) benzene)
A solution prepared by mixing 396 mg (1.5 mmol) of 1,4-dibromo-2,5-dimethylbenzene and 12 ml of tetrahydrofuran in a 25 ml Schlenk tube under an argon atmosphere was cooled to -78 ° C. with dry ice (solid oxygen dioxide) -ethanol. Then, 5.1 ml (7.5 mmol) of a pentane solution of t-butyllithium (f = 1.48) was added dropwise. After the dropwise addition, the solution was stirred for 1 hour while maintaining the reaction temperature at -78 ° C., and 1.12 g (3.3 mmol) of triphenyl germanium chloride was added. The mixture was stirred for 10 minutes while maintaining at -78 ° C, and then reacted at 0 ° C for 2 hours in an ice bath. After completion of the reaction, a suspension obtained by adding 40 ml of water and 40 ml of methylene chloride to the reaction solution was filtered. The obtained filtrate was washed with 20 ml of water twice and 20 ml of ethanol twice, and then dried under reduced pressure to give 2,5-dimethyl-1,4-bis (triphenylgermyl) benzene as a white solid. 0.85 g was obtained (yield 79%).

Example 5 (Synthesis of 2,5-dimethyl-1,4-bis (triphenylgermyl) benzene)
A colorless transparent solution prepared by mixing 350 mg (1.2 mmol) of 1,4-dibromo-2,5-diethylbenzene and 8.5 ml of tetrahydrofuran in a 25 ml Schlenk tube under an argon atmosphere is added with dry ice (solid oxygen dioxide) -ethanol to -78. The mixture was cooled to 0 ° C., and 3.5 ml (6.0 mmol) of a pentane solution (f = 1.7) of t-butyllithium was added dropwise. After the dropwise addition, the solution was stirred for 1 hour while maintaining the reaction temperature at -78 ° C, and then 896 mg (2.6 mmol) of triphenyl germanium chloride was added. The mixture was stirred for 10 minutes while maintaining at -78 ° C, and then stirred at 0 ° C for 2 hours in an ice bath. After completion of the reaction, 40 ml of water and 80 ml of methylene chloride were added to the reaction solution for liquid separation, and the aqueous layer was extracted twice with 20 ml of methylene chloride. The resulting organic layers were combined and dried over 1.2 g of magnesium sulfate. After filtration, methylene chloride was distilled off from the filtrate under reduced pressure, and the resulting residue was washed with 20 ml of warm ethanol and 15 ml of warm hexane and dried under reduced pressure to give 2,5-dimethyl-1,4-bis (tri Phenylgermyl) benzene (0.88 g) was obtained (yield 99%).

Example 6 (Synthesis of 2,5-diethyl-1,4-bis (triphenylgermyl) benzene)
A solution obtained by mixing 350 mg (1.2 mmol) of 1,4-dibromo-2,5-diethylbenzene and 8.5 ml of tetrahydrofuran in a 25 ml Schlenk tube under an argon atmosphere was brought to -78 ° C. with dry ice (solid oxygen dioxide) -ethanol. After cooling, 3.5 ml (6.0 mmol) of a pentane solution of t-butyllithium (f = 1.7) was added dropwise. After the dropwise addition, the solution was stirred for 1 hour while maintaining the reaction temperature at -78 ° C, and then 896 mg (2.6 mmol) of triphenyl germanium chloride was added. The mixture was stirred for 10 minutes while maintaining at -78 ° C, and then stirred at 0 ° C for 2 hours in an ice bath. After completion of the reaction, 40 ml of water and 80 ml of methylene chloride were added to the reaction solution for liquid separation, and the aqueous layer was extracted twice with 20 ml of methylene chloride. The organic layers obtained were combined and dried over 1.2 g of anhydrous magnesium sulfate. After filtration, methylene chloride was distilled off from the filtrate under reduced pressure, and the resulting residue was washed with 20 ml of warm ethanol and 15 ml of warm hexane and dried under reduced pressure to give 2,5-dimethyl-1,4-bis (triphenyl) as a white solid. 0.88 g of (germyl) benzene was obtained (99% yield).

Example 7 (Synthesis of 1,3-bis (triphenylgermyl) benzene)
A solution obtained by mixing 495 mg (1.5 mmol) of 1,3-diiodobenzene and 10 ml of diethyl ether in a 20 ml Schlenk tube under an argon atmosphere was cooled to −78 ° C. with dry ice (solid oxygen dioxide) -ethanol, and n- 2.8 ml (4.5 mmol) of butyllithium in hexane (f = 1.59) was added dropwise. After the dropwise addition, the solution was stirred for 1 hour while maintaining the reaction temperature at -78 ° C., and 1.12 g (3.3 mmol) of triphenyl germanium chloride was added. The mixture was stirred for 15 minutes while maintaining at -78 ° C, and then reacted at 0 ° C for 1 hour in an ice bath. After completion of the reaction, 40 ml of water and 80 ml of methylene chloride were added to the reaction solution for liquid separation, and the aqueous layer was extracted twice with 20 ml of methylene chloride. The organic layers obtained were combined and dried over 1.2 g of anhydrous magnesium sulfate. After filtration, methylene chloride was distilled off from the filtrate under reduced pressure, and the resulting residue was purified by silica gel column chromatography (developing solvent; hexane) to obtain 0.61 g of 1,3-bis (triphenylgermanium) benzene as a white solid. (Yield 59%) was obtained.

Reference Example 1 (Synthesis of 1,4-bis (triphenylgermyl) benzene)
A solution obtained by mixing 236 mg (1.0 mmol) of 1,4-dibromobenzene and 8 ml of tetrahydrofuran in a 20 ml Schlenk tube under an argon atmosphere was cooled to −78 ° C. with dry ice (solid oxygen dioxide) -ethanol, and t-butyllithium. 2.9 ml (5.0 mmol) of a pentane solution (f = 1.7) was added dropwise. After the dropwise addition, the suspension was stirred for 1 hour while maintaining the reaction temperature at -78 ° C, and then 747 mg (2.2 mmol) of triphenyl germanium chloride was added. The mixture was stirred for 5 minutes while maintaining at -78 ° C, and then reacted at 0 ° C for 2 hours in an ice bath. After completion of the reaction, 40 ml of water and 40 ml of methylene chloride were added to the reaction solution for liquid separation, and the suspended methylene chloride layer was filtered. The obtained filtrate was washed with water 20 ml × 2 times, hexane 20 ml × 2 times, ethanol 20 ml × 2 times, and then dried under reduced pressure, and 1,4-bis (triphenylgermanium) benzene as a white solid was added in an amount of 0. 56 g was obtained (82% yield).

Reference Example 2 (phosphorescent complex (Au (IPr) (4F-PE) [(4-fluorophenylethynyl) [1,3-bis (2,6-diisopropylphenyl) imidazol-2-ylidene] gold]) (gold complex 1) Synthesis)
In a 25 ml Schlenk tube under an argon atmosphere, 0.166 g of 1,3-bis (2,6-diisopropylphenyl) imidazolium chloride (IPrH ⁺ Cl ⁻ ; 0.39 mmol), 67 mg of tert-butoxy potassium (85% by mass product; 0.51 mmol) and 6.0 ml of tetrahydrofuran were added, and the mixture was stirred at room temperature for 20 minutes. Tetrahydrofuran was distilled off under reduced pressure, 6.0 ml of toluene was added, and the mixture was reacted at 70 ° C. for 5 minutes. The reaction mixture was filtered, and the filtrate was added dropwise to another 25 ml Schlenk tube to which 174 mg (0.30 mmol) of 4-fluorophenylethynyl (triphenylphosphine) gold and 6.0 ml of toluene were added. After the dropwise addition, the reaction mixture was reacted at 70 ° C. for 2.5 hours. After cooling the reaction mixture to room temperature, toluene was distilled off under reduced pressure, and the resulting white solid was recrystallized with an n-hexane-diethyl ether-methylene chloride system to obtain 10.187 g of a gold complex as a white solid. (Yield 88%).

Example 8 (Preparation of pure blue phosphorescent organic electroluminescence device)
Using glass with an indium tin oxide (hereinafter abbreviated as ITO) film manufactured by ECH as a transparent electrode substrate, and using a vacuum deposition apparatus manufactured by ULVAC KIKKO, on the same substrate at a vacuum of 2 × 10 ⁻³ Pa or less. A hole transport layer 3 composed of 2- (4′-trimethylsilylphenyl) triphenylene is formed in a film having a thickness of 40 nm and host 2-methyl-1,4-bis (triphenylgermyl) benzene (hereinafter abbreviated as Me-p-BTPGB). As a guest phosphorescent complex (Au (IPr) (4F-PE) [(4-fluorophenylethynyl) [1,3-bis (2,6-diisopropylphenyl) imidazol-2-ylidene] gold]) IPr) (abbreviated as 4F-PE)) is 30 nm thick, and the light-emitting layer 4 containing 5.0% by weight of 3- (4-biphenylyl) -4-phenyl-5-tert-butyl The hole blocking layer 5 made of phenyl-1,2,4-triazole (sublimation purified product, hereinafter abbreviated as TAZ) is 30 nm, the electron transport layer 6 made of lithium fluoride (hereinafter abbreviated as LiF) is 0.5 nm, and the electrode 7 As a result, aluminum (hereinafter abbreviated as “Al”) was vacuum-deposited sequentially at 100 nm to produce an electroluminescent device.

  The vacuum deposition was performed by charging the raw material in a crucible placed opposite to the substrate and heating the raw material together with the crucible.

When the ITO electrode 2 of the element is used as a positive electrode and the Al electrode 7 is used as a negative electrode to increase the voltage between the electrodes, the element starts to emit blue light that is clearly visible to the naked eye from around +14 V, and 3.9 cd / second at +23 V. Light was emitted at m ² .

  The current efficiency was 0.017 cd / A at + 20V.

  The emission color of this element was measured using a spectrophotometer manufactured by JASCO. From the spectrum obtained at an interelectrode voltage of +19 V, it was confirmed that the values of chromaticity coordinates were x = 0.172 and y = 0.157. The EL spectrum of the organic electroluminescence element is shown in FIG. 1, and it can be seen that the phosphorescent electroluminescence emission peak has a maximum in the deep blue region near 425 nm.

Preparation of organic electroluminescence device containing SIC0009 as hole transport layer Using glass with ITO coating manufactured by Etch Sea as a transparent electrode substrate and using a vacuum deposition device manufactured by ULVAC Kiko, 2 × 10 ⁻³ Pa or less on the same substrate The hole transport layer 3 made of 2- (4′-trimethylsilylphenyl) triphenylene is 30 nm thick, and the guest (Au (IPr) (4F-PE)) is 5 in the host (Me-p-BTPGB). Electroluminescent device by sequentially vacuum depositing light emitting layer 4 containing 0.0 mass% with a thickness of 30 nm, hole blocking layer 5 made of TAZ 30 nm, electron transport layer 6 made of LiF 0.5 nm, and electrode 7 Al 100 nm. Was made.

  The vacuum deposition was performed by charging the raw material in a crucible placed opposite to the substrate and heating the raw material together with the crucible.

When the ITO electrode 2 of the device is used as a positive electrode and the Al electrode 7 is used as a negative electrode and the voltage between the electrodes is increased, the device starts to emit blue light that is clearly visible to the naked eye from around + 12V, and is 7.4 cd / s at + 25V. Light was emitted at m ² .

  The current efficiency was 0.026 cd / A at + 22V.

  The emission color of this element was measured using a spectrophotometer manufactured by JASCO. From the spectrum obtained at the voltage between the electrodes +18 V, it was confirmed that the values of the chromaticity coordinates were x = 0.176 and y = 0.175. Further, the EL spectrum of the organic electroluminescence element is shown in FIG. 5, and it can be seen that the phosphorescent electroluminescence emission peak maximum is in the deep blue region near 424 nm.

Reference Example 3 (Synthesis of 1,4-bis (triphenylgermyl) benzene)
A colorless transparent solution in which 236 mg (1.0 mmol) of 1,4-dibromobenzene and 8 ml of tetrahydrofuran were mixed in a 20 ml Schlenk tube thoroughly dried and purged with argon under an argon atmosphere with dry ice (solid oxygen dioxide) -ethanol. After cooling to −78 ° C., 2.9 ml (5.0 mmol) of a pentane solution of t-butyllithium (f = 1.7) was added dropwise. After dropping, the reaction suspension turned yellow was stirred for 1 hour while maintaining the reaction temperature at −78 ° C., and 747 mg (2.2 mmol) of triphenyl germanium chloride was added. The mixture was stirred for 5 minutes while maintaining at -78 ° C, and then stirred at 0 ° C for 2 hours in an ice bath. After completion of the reaction, 40 ml of water and 40 ml of methylene chloride were added to the reaction solution for liquid separation, and the suspended methylene chloride layer was subjected to suction filtration. The obtained filtrate was washed with water 20 ml × 2 times, hexane 20 ml × 2 times, ethanol 20 ml × 2 times, and then dried under reduced pressure to obtain 1,4-bis (triphenylgermanium) benzene as a white solid. (Yield 0.56 g, 82% yield).

Reference Example 4 (Synthesis of phosphorescent complex (Au (IPr) (4F-PE) [(4-fluorophenylethynyl) [1,3-bis (2,6-diisopropylphenyl) imidazol-2-ylidene] gold])
Under an argon atmosphere, a 25 ml Schlenk tube was charged with 1,3-bis (2,6-diisopropylphenyl) imidazolium chloride (IPrH + Cl-; 0.166 g, 0.39 mmol), tert-butoxy potassium (85% by mass, 67 mg, 0 mg). 0.51 mmol) and tetrahydrofuran (6.0 ml) were added, and the mixture was stirred at room temperature for 20 minutes. Tetrahydrofuran was distilled off under reduced pressure, toluene (6.0 ml) was added, and the mixture was stirred at 70 ° C. for 5 min. The reaction mixture was filtered and the filtrate was added dropwise to another 25 ml Schlenk tube to which 4-fluorophenylethynyl (triphenylphosphine) gold (174 mg, 0.30 mmol) and 6.0 ml of toluene were added. After the addition, the reaction mixture was heated at 70 ° C. for 2.5 hours. After cooling the reaction mixture to room temperature, toluene was distilled off under reduced pressure, and the resulting white solid was recrystallized with n-hexane / diethyl ether / methylene chloride to obtain 0.187 g of the desired product as a white solid. (Yield 88%).

  The present invention has an organic electroluminescence device (electroluminescence device) having a phosphorescent electroluminescence emission peak with a wavelength of 440 nm or less, and further has a phosphorescent electroluminescence emission peak maximum in a deep blue region of 440 nm or less, and the emission color is CIE ( International Lighting Commission) The present invention relates to an element having a color coordinate system having a y coordinate of less than 0.180 and an element material for the organic electroluminescence element. The organic electroluminescence device of the present invention is considered to be a device that is useful for realizing the completion of a full-color display, for example.

Claims (12)

  An organic electroluminescence element in which a light emitting layer or a plurality of organic compound thin layers including a light emitting layer is formed between a pair of electrodes, and has a phosphorescent electroluminescence emission peak having a wavelength of 440 nm or less. element.   The organic electroluminescence according to claim 1, which has a phosphorescence electroluminescence emission peak maximum in a deep blue region of 440 nm or less, an emission color is an International Commission on Illumination (CIE) color system, and a y coordinate is less than 0.180. element.   The organic electroluminescent element of Claim 1 or 2 which contains a 1 or multiple types of germanium compound in a light emitting layer. The germanium compound has the general formula (1):

(In formula, L is 0-2 and k is an integer of 0-3.
R ^{1 to} R ⁶ may be the same or different and are an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, an aryl group, a heteroaryl group, an alkoxy group, or an aryloxy group. In these groups, any hydrogen atom is a halogen atom, alkyl group, cycloalkyl group, alkenyl group, aryl group, aralkyl group, alkoxy group, aryloxy group, alkyl mercapto group, aryl mercapto group or organosilyl group. It may be replaced with.
Further, R ^{1 to} R ⁶ may be bonded to each other to form a ring, and the bonding group that connects the rings is a single bond, an ether bond, a thioether bond, an alkylene group, an oxaalkylene group, or a thiaalkylene. It is a group.
X is an alkyl group, cycloalkyl group, alkenyl group, aryl group, aralkyl group, alkoxy group, aryloxy group, alkyl mercapto group, aryl mercapto group or amino group having a substituent. )
The organic electroluminescent element of Claim 3 which is a germanium compound shown by these. The germanium compound has the general formula (1a):

(Wherein k, X and R ^{1 to} R ⁶ have the same meanings as in claim 4).
The organic electroluminescent element of Claim 4 which is a germanium compound shown by these. The germanium compound has the following formula (2):

(In the formula, l is an integer of 0 to 2, m is an integer of 1 to 3, n is an integer of 1 to 3, and k is as defined above. Ar may be the same or different, and aryl. A group or a heteroaryl group, in which any hydrogen atom is a halogen atom, alkyl group, cycloalkyl group, alkenyl group, aryl group, aralkyl group, alkoxy group, aryloxy group alkyl mercapto group, aryl mercapto group It may be substituted with a group or an organosilyl group, and different Ars may be substituted with the same Ge atom, in which case the sum of the number of different Ar groups is equal to m. May be bonded via a single bond, an ether bond, a thioether bond, an alkylene group, an oxaalkylene group or a thiaalkylene group, and R is an alkyl group, Roarukiru group, an alkenyl group, an aralkyl group, .X an alkoxy group or an aryloxy group is a germanium compound represented by the same as in the claim 4.), According to claim 4 organic electroluminescent device according. The germanium compound is (2a):

(Wherein k, m, n, X, Ar and R have the same meanings as in claim 6).
The organic electroluminescent element of Claim 6 which is a germanium compound shown by these. The germanium compound has the general formula (2b):

(In the formula, k, X and Ar have the same meanings as in claim 7.)
The organic electroluminescent element of Claim 7 which is a germanium compound shown by these. The germanium compound has the formulas (1c) to (1g):

The organic electroluminescence device according to claim 8, which is at least one compound selected from the group of compounds represented by:   The organic electroluminescent element of any one of Claims 3-9 in which a light emitting layer contains multiple types of germanium compounds. Multiple types of light emitting layers having a single or different substituent structure:

(In the formula, L represents a nitrogen-containing heterocyclic carbene ligand. Y represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or a heterocyclic group. Or a plurality of hydrogen atoms may be substituted with halogen atoms, alkyl groups, cycloalkyl groups, alkenyl groups, aryl groups, aralkyl groups, alkoxy groups, aryloxy groups, dialkylamino groups, carboalkyl groups, or carboaryl groups. Also, a plurality of hydrogen atoms on the carbon atom of Y are substituted with an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a dialkylamino group, a carboalkyl group or a carboaryl group. And the adjacent groups may be bonded to form a ring). The organic electroluminescence device according to any one. Including the hole transport layer, the hole transport layer is a single type or a plurality of types having different substituent configurations:

(Wherein Z is a single or plural alkyl group, cycloalkyl group, aryl group, aralkyl group or heterocyclic group. Note that one or plural hydrogen atoms on the carbon atom of Z are a halogen atom, An alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a dialkylamino group, a carboalkyl group, a carboaryl group, or an organosilyl group. The organic electroluminescent element of any one of Claims 1-11 containing the compound which becomes.

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