JP2005306864A - Organic electroluminescent device and silicon compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent device having good light emission characteristics, crystal driving durability and preservation stability. <P>SOLUTION: The organic electroluminescent device has at least one layer of organic layers including light-emitting layers between a pair of electrodes and contains at least one species of compounds expressed by general formula (1) in the organic layer. In the formula, R<SP>11</SP>and R<SP>12</SP>independently expresses each an aryl or a heteroaryl, when R<SP>11</SP>and R<SP>12</SP>are a phenyl, R<SP>11</SP>and R<SP>12</SP>do not have an N-containing heterocyclic group as a substituent on them; Ar<SP>11</SP>and Ar<SP>12</SP>independently express each a group expressed by general formula (2). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an organic electroluminescent element capable of emitting light by converting electric energy into light.

  Today, research and development on various display elements are active, and among them, an organic electroluminescence (EL) element (hereinafter, sometimes referred to as an EL element, a light emitting element, or a light emitting element of the present invention) has high luminance at a low voltage. Therefore, it is attracting attention as a promising display element.

In order to improve device durability, Patent Document 1 proposes specific silane compounds and light-emitting devices containing these, and (4-25), (4-26), (4-27) are proposed in the Patent Document. (4-28) is disclosed, but further improvement in durability has been demanded for elements using these.
JP 2000-351966 A

  An object of the present invention is to provide an organic electroluminescence device having good light emission characteristics, device driving durability, and storage stability, and a compound that makes it possible to realize such a device.

This object has been achieved by the following means.
(1) An organic electroluminescent device having at least one organic layer including a light emitting layer between a pair of electrodes, wherein the organic layer contains at least one compound represented by the following general formula (1) Electroluminescent device.

(In the formula, R ¹¹ and R ¹² each independently represents an aryl group or a heteroaryl group. When R ¹¹ and R ¹² are phenyl groups, nitrogen-containing heterocycles are substituted on R ¹¹ and R ¹² as substituents. (Ar ¹¹ and Ar ¹² each independently represent a group represented by the general formula (2).)

(In the formula, Ar ²¹ represents an arylene group or a heteroarylene group, R ²¹ , R ²² , R ²³ , and R ²⁴ each independently represents a substituent or a hydrogen atom. L ² represents a substituted or unsubstituted o-arylene. , Vinylene, -NR- (R represents a substituent), -O-, or -S-, and m represents 0 or 1.)
(2) The organic electroluminescent device according to claim 1, wherein, in the general formula (1), R ¹¹ and R ¹² are an unsubstituted aryl group or an unsubstituted heteroaryl group.
(3) The organic electroluminescent element as described in (1) or (2), wherein m is 0 in the general formula (2).
(4) The organic electroluminescent element according to item (1) or (2), wherein in general formula (2), m is 1 and L ² is substituted or unsubstituted o-arylene or vinylene.
(5) The organic electroluminescence according to item (1), wherein the compound represented by the general formula (1) is a compound represented by the following general formula (3) or general formula (4) element.

（式中、Ｒ^３１、Ｒ^３２、Ｒ^３３、Ｒ^３４、Ｒ^３５、Ｒ^３６、Ｒ^４１、Ｒ^４２、Ｒ^４３、Ｒ^４４、Ｒ^４５、Ｒ^４６はそれぞれ独立にアルキル基、アリール基、互いに結合して芳香環を形成する基を表す。ａ、ｂ、ｇ、ｈはそれぞれ独立に０から４の整数を表す。ｃ、ｄはそれぞれ独立に０から８の整数を表す。ｉ、ｊはそれぞれ独立に０から２の整数を表す。ｅ、ｆ、ｋ、ｌはそれぞれ独立に０〜５の整数を表す。）
（６）一般式（３）または一般式（４）で表される化合物。

(In the formula, R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ , R ³⁶ , R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ are each independently an alkyl group, an aryl group, A, b, g and h each independently represents an integer of 0 to 4, c and d each independently represents an integer of 0 to 8; Each independently represents an integer of 0 to 2. e, f, k, l each independently represents an integer of 0 to 5)
(6) The compound represented by general formula (3) or general formula (4).

(In the formula, R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ , R ³⁶ , R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ are each independently an alkyl group, an aryl group, A, b, g and h each independently represents an integer of 0 to 4, c and d each independently represents an integer of 0 to 8; Each independently represents an integer of 0 to 2. e, f, k, l each independently represents an integer of 0 to 5)

  The light emitting device of the present invention is excellent in light emitting characteristics and durability.

  A preferred embodiment of the present invention is an organic electroluminescent device having at least one organic layer including a light emitting layer between a pair of electrodes, wherein the compound represented by the following general formula (1) is contained in the organic layer. It is an organic electroluminescent element containing at least one kind.

（式中、Ｒ^１１、Ｒ^１２は互いに独立にアリール基、ヘテロアリール基を表すが、Ｒ^１１、Ｒ^１２がフェニル基である場合、Ｒ^１１、Ｒ^１２上に置換基として含窒素へテロ環基を有することはない。Ａｒ^１１、Ａｒ^１２は互いに独立に一般式（２）で表される基を表す。）

（式中、Ａｒ^２１はアリーレン基またはヘテロアリーレン基を表し、Ｒ^２１、Ｒ^２２、Ｒ^２３、Ｒ^２４はそれぞれ独立に置換基または水素原子を表す。Ｌ^２は置換もしくは無置換のｏ−アリーレン、ビニレン、−ＮＲ−（Ｒは置換基を表す）、−Ｏ−、または−Ｓ−を表し、ｍは０または１を表す。）

(In the formula, R ¹¹ and R ¹² each independently represents an aryl group or a heteroaryl group. When R ¹¹ and R ¹² are phenyl groups, nitrogen-containing heterocycles are substituted on R ¹¹ and R ¹² as substituents. (Ar ¹¹ and Ar ¹² each independently represent a group represented by the general formula (2).)

(In the formula, Ar ²¹ represents an arylene group or a heteroarylene group, R ²¹ , R ²² , R ²³ , and R ²⁴ each independently represents a substituent or a hydrogen atom. L ² represents a substituted or unsubstituted o-arylene. , Vinylene, -NR- (R represents a substituent), -O-, or -S-, and m represents 0 or 1.)

The general formula (1) will be described. R ¹¹ and R ¹² represent an aryl group or a heteroaryl group. R ¹¹ and R ¹² are preferably monocyclic, bicyclic, and tricyclic aryl groups or heteroaryl groups, more preferably phenyl groups, naphthyl groups, pyridyl groups, and carbazolyl groups, and most preferably phenyl groups. is there. R ¹¹ and R ¹² may have a substituent. When R ¹¹ and R ¹² are phenyl groups, they do not have a nitrogen-containing heterocyclic group as a substituent on R ¹¹ and R ¹² . Preferred examples of the substituent include the following substituent A.

(Substituent 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, iso-propyl, tert-butyl, n-octyl, n- Decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, For example, 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, For example, propargyl, 3-pentynyl, etc.), aryl groups (preferably having 6 to 30 carbon atoms, more preferably A prime number of 6 to 20, particularly preferably a carbon number of 6 to 12, such as phenyl, p-methylphenyl, naphthyl, anthranyl, etc., an amino group (preferably a carbon number of 0 to 30, more preferably a carbon number). 0 to 20, particularly preferably 0 to 10 carbon atoms, such as amino, methylamino, dimethylamino, diethylamino, dibenzylamino, diphenylamino, ditolylamino, etc.), an alkoxy group (preferably 1 to 1 carbon atoms). 30, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms, and examples thereof include methoxy, ethoxy, butoxy, 2-ethylhexyloxy and the like, and aryloxy groups (preferably 6 carbon atoms). -30, more preferably 6-20 carbons, particularly preferably 6-12 carbons, Phenyloxy, 1-naphthyloxy, 2-naphthyloxy, etc.), heteroaryloxy 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.), acyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, Acetyl, 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, Ethoxycarbonyl, etc.), aryloxycarbonyl group

(Preferably 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonyl), acyloxy group (preferably 2 to 30 carbon atoms). More preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as acetoxy and benzoyloxy), acylamino groups (preferably 2 to 30 carbon atoms, more preferably 2 carbon atoms). To 20, particularly preferably 2 to 10 carbon atoms, such as acetylamino, benzoylamino, etc.), an alkoxycarbonylamino group (preferably 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, especially Preferably, it has 2 to 12 carbon atoms, and examples thereof include methoxycarbonylamino and the like. Rubonylamino group (preferably having 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonylamino), sulfonylamino group (preferably C1-C30, More preferably, it is C1-C20, Most preferably, it is C1-C12, for example, methanesulfonylamino, benzenesulfonylamino, etc. are mentioned), sulfamoyl groups (preferably C0-C0). 30, more preferably 0 to 20 carbon atoms, particularly preferably 12 to 12 carbon atoms, such as sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenylsulfamoyl, etc.), carbamoyl group (preferably 1-30 carbon atoms, more preferably 1-20 carbon atoms, particularly preferably charcoal 1 to 12, for example, carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl, etc.), alkylthio group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably carbon number). 1 to 12, for example, methylthio, ethylthio, etc.), arylthio groups (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio A heteroarylthio group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms such as pyridylthio, 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio and the like. A phonyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include mesyl and tosyl. ), Sulfinyl group

(Preferably 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfinyl, benzenesulfinyl, etc.), ureido group (preferably 1 carbon atom) To 30, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as ureido, methylureido, phenylureido, etc.), phosphoric acid amide groups (preferably 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), hydroxy group, mercapto group, halogen atom (for example, fluorine atom) , Chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxam Group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include nitrogen atom, oxygen atom, sulfur atom, Specifically, examples include imidazolyl, pyridyl, quinolyl, furyl, thienyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, carbazolyl group, azepinyl group, etc., 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.

As the substituent that R ¹¹ and R ¹² have, an alkyl group and an aryl group are preferable, an aryl group is more preferable, and a phenyl group is more preferable, but R ¹¹ and R ¹² most preferably have no substituent.

Ar ¹¹ and Ar ¹² represent a group represented by the general formula (2), and may be the same as or different from each other.

Next, the group represented by the general formula (2) will be described.
Ar ²¹ represents an arylene group or a heteroarylene group. Ar ²¹ is preferably a phenylene group, a biphenylene group, a naphthylene group, an anthranylene group, or a pyridylene group, more preferably a phenylene group or a biphenylene group, and still more preferably a p-phenylene group.

Ar ²¹ may further have a substituent, and examples of the substituent are the same as the substituent A in R ¹¹ and R ¹² described above, and preferred examples are also the same, but Ar ²¹ has a substituent. Most preferably not.

R ²¹ , R ²² , R ²³ and R ²⁴ represent a substituent or a hydrogen atom. Examples of the substituent are the same as the substituent A in R ¹¹ and R ¹² , and are preferably an alkyl group, an aryl group, a heteroaryl group, and a group that is bonded to form an aromatic ring. A group that forms a ring is more preferable, and a group that combines to form an aromatic ring is more preferable.

L ² represents substituted or unsubstituted o-arylene, vinylene, —NR—, —O—, or —S—. R in —NR— represents a substituent, which is the same as the example of the substituent A.

L ² is preferably substituted or unsubstituted o-arylene, vinylene, and —NR—, more preferably unsubstituted o-arylene and vinylene, and still more preferably unsubstituted o-phenylene.

m represents 0 or 1, and is preferably 0. When m = 0, it means that the carbon atoms to which R ²² and R ²³ are bonded are connected to each other.

  Specific examples of the compound of the present invention are shown below, but the present invention is not limited thereto.

Another preferred embodiment of the present invention is a compound represented by formula (3) or formula (4).

(In the formula, R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ , R ³⁶ , R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ are each independently an alkyl group, an aryl group, A, b, g and h each independently represents an integer of 0 to 4, c and d each independently represents an integer of 0 to 8; Each independently represents an integer of 0 to 2. e, f, k, l each independently represents an integer of 0 to 5)

The general formula (3) will be described. In the general formula (3), R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ , and R ³⁶ each independently represent an alkyl group, an aryl group, or a group that is bonded to each other to form an aromatic ring. R ³¹ , R ³² , R ³³ , R ³⁴ , and R ³⁵ are preferably aryl groups, more preferably phenyl groups, naphthyl groups, and biphenyl groups, and even more preferably phenyl groups.

  a and b each independently represent an integer of 0 to 4, preferably 0 to 2, more preferably 0 or 1, and most preferably 0.

  c and d each independently represents an integer of 0 to 8, preferably 0 to 6, more preferably 0 to 4, and most preferably 0. e and f represent an integer of 0 to 5, preferably 0 to 3, more preferably 0 or 1, and most preferably 0.

Next, general formula (4) will be described. In the general formula (4), R ⁴¹ , R ⁴² , R ⁴⁵ , and R ⁴⁶ each independently represent an alkyl group, an aryl group, or a group that combines with each other to form an aromatic group, and preferred examples include the R ³¹ , R ^32. , R ³³ , R ³⁴ , R ³⁵ , R ³⁶ are the same.

R ⁴³ and R ⁴⁴ each independently represents an alkyl group, an aryl group, or a group that is bonded to each other to form an aromatic ring. Examples of the substituent are the same as R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ , and R ^36, and are preferably an aryl group or a group that is bonded to each other to form an aromatic ring or a heteroaromatic ring. More preferably, they are bonded to each other to form an aromatic ring, and most preferably bonded to each other to form a benzene ring.

  g and h each independently represent an integer of 0 to 4, preferably 0 to 2, more preferably 0 or 1, and most preferably 0. i and j each independently represents an integer of 0 to 2, preferably 1 or 2, and most preferably 2. k and l represent an integer of 0 to 5, preferably 0 to 3, more preferably 0 or 1, and most preferably 0.

  Specific compound examples of the compound represented by the general formula (3) include (1-1) and (1-2) among the above specific compound examples, and are represented by the general formula (4). Specific examples of the compound include (2-1), (2-3), (2-5), (2-6), (2-7), (2-9), (2-10), and the like. However, the present invention is not limited to these.

  A method for producing the compound of the present invention will be described. The compound represented by the general formula (3) or the general formula (4) can be synthesized, for example, according to the following scheme.

(In the formula, X and Y represent a halogen atom, and R ¹ , R ² , R ³ , and R ⁴ each independently represent an alkyl group, an aryl group, or a group that combines with each other to form an aromatic ring. A, b Represents an integer of 0 to 4, and c and d represent an integer of 0 to 5.)

  The intermediate A in the scheme can be synthesized by utilizing various known carbon-silicon bond forming reactions, and the method is not particularly limited. For example, The Chemistry of Organic Silicon Compound, Part 1 (The Chemistry of Organic Silicon compounds, part 1) (John Wiley & Sons) It can synthesize | combine using the method described in P.655-761.

  The compound represented by the general formula (3) or the general formula (4) can be synthesized from the intermediate A using various known carbon-nitrogen bond forming reactions, and the method is not particularly limited.・ Journal of American Chemical Society, 118, 7215 (1996) or Journal of American Chemical Society, 118, 7217 (1996) A method of synthesis using a method using a palladium catalyst is preferred.

The palladium catalyst is not particularly limited, and examples thereof include palladium tetrakistriphenylphosphine, palladium carbon, palladium acetate, palladium dichloride (dppf) (dppf: 1,1′-bisdiphenylphosphinoferrocene) and the like. A ligand such as triphenylphosphine or P (t-Bu) ₃ may be added simultaneously.

  In this reaction, it is preferable to use a base. Although the kind of base to be used is not particularly limited, examples thereof include sodium carbonate, sodium acetate, potassium carbonate, rubidium carbonate, triethylamine, sodium t-butoxy, potassium t-butoxy and the like. The amount of the base to be used is not particularly limited, but is preferably 0.1 to 20 equivalents, particularly preferably 1 to 10 equivalents with respect to carbazole or a derivative thereof, iminostilbene or a derivative thereof.

  In this reaction, it is preferable to use a solvent. Although the solvent to be used is not particularly limited, for example, ethanol, water, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dimethylformamide, toluene, tetrahydrofuran, xylene, mesitylene, and a mixed solvent thereof can be used.

  Although the reaction temperature at the time of synthesize | combining the compound of this invention does not have limitation in particular, Preferably it is 20-220 degreeC, Preferably it is 20-180 degreeC, More preferably, it is 20-160 degreeC.

  The compound represented by the general formula (1), the general formula (3), or the general formula (4) (hereinafter, also referred to as the compound of the present invention) may be a low molecular compound, or an oligomer compound or a polymer compound. (The weight average molecular weight (in terms of polystyrene) is preferably 1000 to 5000000, more preferably 2000 to 1000000, and still more preferably 3000 to 100,000). In the case of a polymer compound, a structure represented by the general formula (1), the general formula (2), the general formula (3), or the general formula (4) may be included in the polymer main chain. It may be included in the chain. In the case of a polymer compound, it may be a homopolymer compound or a copolymer. The compound of the present invention is preferably a low molecular compound.

  The light emitting device of the present invention will be described. The light emitting device of the present invention is not particularly limited as long as it is a device using the compound of the present invention, such as a system, a driving method, and a usage form. An organic EL (electroluminescence) element can be mentioned as a typical light emitting element.

  In the light emitting device of the present invention, the action of the compound of the present invention and the layer to be contained are not particularly limited, but are preferably contained in the hole transport layer or the light emitting layer, more preferably contained in the light emitting layer. More preferably, it is contained as a host material in the layer.

In the light-emitting device of the present invention, the organic layer preferably contains the compound of the present invention as a main component. When the compound of this invention is contained in a positive hole transport layer, it is preferable to use the compound of this invention individually or in multiple, Furthermore, you may mix other compounds other than this invention.
On the other hand, when the compound of the present invention is contained in the light emitting layer, the ratio of the compound of the present invention to the light emitting material is preferably 0.01% by mass or more and 20% by mass or less of the light emitting material with respect to the total mass of the layer. The content is more preferably 0.1% by mass or more and 15% by mass or less, and further preferably 0.5% by mass or more and 10% by mass or less.

The light-emitting material contained in the light-emitting element of the present invention may be either a fluorescent compound that emits light from singlet excitons or a phosphorescent compound that emits light from triplet excitons. For example, benzoxazole and derivatives thereof, benzimidazole and derivatives thereof, benzothiazole and derivatives thereof, styrylbenzene and derivatives thereof, polyphenyl and derivatives thereof, diphenylbutadiene and derivatives thereof, tetraphenylbutadiene and derivatives thereof , Naphthalimide and their derivatives, coumarin and their derivatives, condensed aromatic compounds, perinones and their derivatives, oxadiazole and their derivatives, oxazine and their derivatives, aldazine and their derivatives, pyralidine and their derivatives , Cyclopentadiene and their derivatives, bisstyrylanthracene and their derivatives, quinacridone and their derivatives, pyrrolopyridine And their derivatives, thiadiazolopyridine and their derivatives, cyclopentadiene and their derivatives, styrylamine and their derivatives, diketopyrrolopyrrole and their derivatives, aromatic dimethylidin and their compounds, 8-quinolinol and their Metal complexes of pyroxene derivatives, metal complexes of pyromethene and their derivatives, various metal complexes represented by rare earth complexes, transition metal complexes, polymer compounds such as polythiophene, polyphenylene, polyphenylene vinylene, organic silanes and their derivatives, etc. It is done. The light-emitting material is preferably a condensed aromatic compound, quinacridone and derivatives thereof, diketopyrrolopyrrole and derivatives thereof, metal complexes of pyromethene and derivatives thereof, rare earth complexes, transition metal complexes, more preferably condensed aromatic compounds , A transition metal complex.

  In the case of a phosphorescent compound that emits light from triplet excitons, a transition metal complex is particularly preferable. The central metal of the transition metal complex is not particularly limited, but is preferably iridium, platinum, rhenium, or ruthenium, more preferably iridium or platinum, and particularly preferably iridium. Of the transition metal complexes, orthometalated complexes are very preferred. The orthometalated complex is “A basic and application of organometallics” written by Akio Yamamoto, pages 150 and 232, Hankabo (1982), H. Yersin, “Photochemistry and Photophysics and Photophysics of Coordination Compound”, 71-77 and 135-146, published by Springer-Verlag, Inc. (1987) It is a general term for a group of compounds.

  The phosphorescent material preferably has a phosphorescent quantum yield of 70% or higher at 20 ° C. or higher, more preferably 80% or higher, and still more preferably 85% or higher.

  Examples of the phosphorescent material include US 6303231 B1, US 6097147, WO 00/57676, WO 00/70655, WO 01/08230, WO 01/39234 A2, WO 01/41512 A1, WO 02/02714 A2, and WO 02 /. Japanese Patent Application No. 15645 A1, Japanese Patent Application No. 2001-247859, Japanese Patent Application No. 2000-33561, Japanese Patent Application No. 2001-189539, Japanese Patent Application No. 2001-248165, Japanese Patent Application No. 2001-339684, Japanese Patent Application No. 2001-239281, Japanese Patent Application No. 2001-219909, 2002-226495, JP 2002-234894, JP 2001-247659, JP 2001-298470, JP 2002-173675, JP 2002-203678, JP 2002-2036 79 and other publications and specifications, Nature, 395, 151 (1998), Applied Physics Letters, 75, 4 (1999), Polymer Preprints (Polymer Preprints), 41, 770 (2000), Journal of American Chemical Society, 123, 4304 (2001), Applied Physics Letters (Appli) Physics Letters), 79, 2082 (1999) and the like can be suitably used.

  The method for forming the organic layer of the light-emitting device containing the compound of the present invention is not particularly limited, but methods such as resistance heating vapor deposition, electron beam, sputtering, molecular lamination method, coating method, inkjet method, printing method, etc. In view of characteristics and production, resistance heating vapor deposition, coating method, and transfer method are preferable.

  The light-emitting element of the present invention is an element in which at least one organic compound film including a light-emitting layer is formed between a pair of electrodes of an anode and a cathode. In addition to the light-emitting layer, a hole injection layer, a hole transport layer, an electron injection layer, An electron transport layer, a protective layer, and the like may be included, and each of these layers may have other functions. Various materials can be used for forming each layer.

  The substrate used in the light-emitting device of the present invention is not particularly limited, but inorganic materials such as zirconia-stabilized yttrium and glass, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyethylene, polycarbonate, and polyethersulfone. High molecular weight materials such as polyarylate, allyl diglycol carbonate, polyimide, polycycloolefin, norbornene resin, poly (chlorotrifluoroethylene), Teflon (registered trademark), polytetrafluoroethylene-polyethylene copolymer good.

  The anode supplies holes to a hole injection layer, a hole transport layer, a light emitting layer, and the like, and a metal, an alloy, a metal oxide, an electrically conductive compound, or a mixture thereof can be used. Is a material having a work function of 4 eV or more. Specific examples include conductive metal oxides such as tin oxide, zinc oxide, indium oxide and indium tin oxide (ITO), metals such as gold, silver, chromium and nickel, and these metals and conductive metal oxides. Inorganic conductive materials such as copper iodide and copper sulfide, organic conductive materials such as polyaniline, polythiophene, and polypyrrole, and laminates of these with ITO, preferably conductive metals It is an oxide, and ITO is particularly preferable from the viewpoint of productivity, high conductivity, transparency, and the like. Although the film thickness of the anode can be appropriately selected depending on the material, it is usually preferably in the range of 10 nm to 5 μm, more preferably 50 nm to 1 μm, still more preferably 100 nm to 500 nm.

  As the anode, a layer formed on a soda-lime glass, non-alkali glass, a transparent resin substrate or the like is usually used. When glass is used, it is preferable to use non-alkali glass as the material in order to reduce ions eluted from the glass. Moreover, when using soda-lime glass, it is preferable to use what gave barrier coatings, such as a silica. The thickness of the substrate is not particularly limited as long as it is sufficient to maintain the mechanical strength, but when glass is used, a thickness of 0.2 mm or more, preferably 0.7 mm or more is usually used.

Various methods are used for producing the anode depending on the material. For example, in the case of ITO, an electron beam method, a sputtering method, a resistance heating vapor deposition method, a chemical reaction method (sol-gel method, etc.), a coating of a dispersion of indium tin oxide, etc. A film is formed by this method.
The anode can be subjected to cleaning or other treatments to lower the drive voltage of the element or increase the light emission efficiency. For example, in the case of ITO, UV-ozone treatment, plasma treatment, etc. are effective.

  The cathode supplies electrons to the electron injection layer, the electron transport layer, the light emitting layer, etc., and the adhesion, ionization potential, stability, etc., between the negative electrode and the adjacent layer such as the electron injection layer, electron transport layer, light emitting layer, etc. Selected in consideration of As a material for the cathode, a metal, an alloy, a metal halide, a metal oxide, an electrically conductive compound, or a mixture thereof can be used. Specific examples include an alkali metal (for example, Li, Na, K, etc.) and its fluoride. Or oxides, alkaline earth metals (eg Mg, Ca, etc.) and their fluorides or oxides, gold, silver, lead, aluminum, sodium-potassium alloys or their mixed metals, lithium-aluminum alloys or their mixtures Examples thereof include metals, magnesium-silver alloys or mixed metals thereof, rare earth metals such as indium and ytterbium, preferably materials having a work function of 4 eV or less, more preferably aluminum, lithium-aluminum alloys or mixed metals thereof. , Magnesium-silver alloys or mixed metals thereofThe cathode can take not only a single layer structure of the compound and the mixture but also a laminated structure containing the compound and the mixture. For example, a laminated structure of aluminum / lithium fluoride and aluminum / lithium oxide is preferable. The film thickness of the cathode can be appropriately selected depending on the material, but is usually preferably in the range of 10 nm to 5 μm, more preferably 50 nm to 1 μm, still more preferably 100 nm to 1 μm.

For production of the cathode, methods such as an electron beam method, a sputtering method, a resistance heating vapor deposition method, and a coating method are used, and a metal can be vapor-deposited alone or two or more components can be vapor-deposited simultaneously. Furthermore, a plurality of metals can be vapor-deposited simultaneously to form an alloy electrode, or a previously prepared alloy may be vapor-deposited.
The sheet resistance of the anode and cathode is preferably low, and is preferably several hundred Ω / □ or less.

The material of the light emitting layer is a function that can inject holes from the anode or hole injection layer, hole transport layer and cathode or electron injection layer, electron transport layer when an electric field is applied, Any material can be used as long as it can form a layer having a function of transferring injected charges and a function of emitting light by providing a recombination field of holes and electrons, such as benzoxazole, benzimidazole, and benzothiazole. , Styrylbenzene, polyphenyl, diphenylbutadiene, tetraphenylbutadiene, naphthalimide, coumarin, perylene, perinone, oxadiazole, aldazine, pyralidine, cyclopentadiene, bisstyrylanthracene, quinacridone, pyrrolopyridine, thiadiazolopyridine, cyclopentadiene , Styrylamine, Represented by aromatic dimethylidin compounds, various metal complexes represented by 8-quinolinol metal complexes and rare earth complexes, polymer compounds such as polythiophene, polyphenylene, polyphenylene vinylene, organic silanes, iridium trisphenylpyridine complexes, and platinum porphyrin complexes Transition metal complexes and derivatives thereof. At least one of the materials of the light emitting layer is a phosphorescent material. Although the film thickness of a light emitting layer is not specifically limited, Usually, the thing of the range of 1 nm-5 micrometers is preferable, More preferably, it is 5 nm-1 micrometer, More preferably, it is 10 nm-500 nm.
The method for forming the light emitting layer is not particularly limited, but resistance heating vapor deposition, electron beam, sputtering, molecular lamination method, coating method (spin coating method, casting method, dip coating method, etc.), inkjet method, printing method , LB method, transfer method and the like are used, preferably resistance heating vapor deposition and coating method.

  The light emitting layer may be formed of a single compound or a plurality of compounds. Further, the light emitting layer may be one or plural, and each layer may emit light with different emission colors, for example, white light may be emitted. White light may be emitted from a single light emitting layer. When there are a plurality of light emitting layers, each light emitting layer may be formed of a single material or a plurality of compounds.

The light emitting layer of the organic electroluminescent element of the present invention may have at least one laminated structure. The number of stacked layers is preferably 2 or more and 50 or less, more preferably 4 or more and 30 or less, and still more preferably 6 or more and 20 or less.

The thickness of each layer constituting the stack is not particularly limited, but is preferably 0.2 nm or more and 20 nm or less, more preferably 0.4 nm or more and 15 nm or less, further preferably 0.5 nm or more and 10 nm or less, and more preferably 1 nm or more and 5 nm or less. Particularly preferred.

  The light emitting layer of the organic electroluminescent element of the present invention may have a plurality of domain structures. The light emitting layer may have another domain structure. The diameter of each domain is preferably from 0.2 nm to 10 nm, more preferably from 0.3 nm to 5 nm, still more preferably from 0.5 nm to 3 nm, and particularly preferably from 0.7 nm to 2 nm.

  The material of the hole injection layer and the hole transport layer may be any one having a function of injecting holes from the anode, a function of transporting holes, or a function of blocking electrons injected from the cathode. Good. Specific examples include carbazole, triazole, oxazole, oxadiazole, imidazole, polyarylalkane, pyrazoline, pyrazolone, phenylenediamine, arylamine, amino-substituted chalcone, styrylanthracene, fluorenone, hydrazone, stilbene, silazane, aromatic group Tertiary amine compounds, styrylamine compounds, aromatic dimethylidin compounds, porphyrin compounds, polysilane compounds, poly (N-vinylcarbazole), aniline copolymers, thiophene oligomers, conductive polymer oligomers such as polythiophene, organic Examples include silane derivatives, carbon films, compounds of the present invention, and derivatives thereof. The thicknesses of the hole injection layer and the hole transport layer are not particularly limited, but those in the range of usually 1 nm to 5 μm are preferable,

More preferably, it is 5 nm-1 micrometer, More preferably, it is 10 nm-500 nm. The hole injection layer and the hole transport layer may have a single-layer structure composed of one or more of the materials described above, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.
As a method for forming the hole injection layer and the hole transport layer, a vacuum deposition method, an LB method, a method in which the hole injection / transport material is dissolved or dispersed in a solvent (a spin coating method, a casting method, a dip coating method). Etc.), an inkjet method, a printing method, and a transfer method are used. In the case of the coating method, it can be dissolved or dispersed together with the resin component. Examples of the resin component include polyvinyl chloride, polycarbonate, polystyrene, polymethyl methacrylate, polybutyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, and poly (N -Vinyl carbazole), hydrocarbon resin, ketone resin, phenoxy resin, polyamide, ethyl cellulose, vinyl acetate, ABS resin, polyurethane, melamine resin, unsaturated polyester resin, alkyd resin, epoxy resin, silicone resin, and the like.

  The material for the electron injection layer and the electron transport layer may be any material having any one of a function of injecting electrons from the cathode, a function of transporting electrons, and a function of blocking holes injected from the anode. Specific examples include fragrances such as triazole, oxazole, oxadiazole, imidazole, fluorenone, anthraquinodimethane, anthrone, diphenylquinone, thiopyrandioxide, carbodiimide, fluorenylidenemethane, distyrylpyrazine, naphthalene, and perylene. Various metal complexes represented by cyclic tetracarboxylic acid anhydrides, metal complexes of phthalocyanine, 8-quinolinol, metal phthalocyanines, metal complexes having benzoxazole and benzothiazole as ligands, organic silanes, compounds of the present invention, and Examples thereof include derivatives thereof. The thicknesses of the electron injection layer and the electron transport layer are not particularly limited, but those in the range of usually 1 nm to 5 μm are preferable,

More preferably, it is 5 nm-1 micrometer, More preferably, it is 10 nm-500 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.
As a method for forming the electron injection layer and the electron transport layer, a vacuum deposition method, an LB method, a method in which the electron injection / transport material is dissolved or dispersed in a solvent (a spin coating method, a casting method, a dip coating method, etc.), An ink jet method, a printing method, a transfer method, or the like is used. In the case of the coating method, it can be dissolved or dispersed together with the resin component. As the resin component, for example, those exemplified in the case of the hole injection transport layer can be applied.

As a material for the protective layer, any material may be used as long as it has a function of preventing substances that promote device deterioration such as moisture and oxygen from entering the device. Specific examples thereof include metals such as In, Sn, Pb, Au, Cu, Ag, Al, Ti, and Ni, MgO, SiO, SiO ₂ , Al ₂ O ₃ , GeO, NiO, CaO, BaO, and Fe ₂ O. ₃ , metal oxides such as Y ₂ O ₃ , TiO ₂ , metal fluorides such as MgF ₂ , LiF, AlF ₃ , CaF ₂ , SiN _x , SiO _x N _y Such as nitride, polyethylene, polypropylene, polymethyl methacrylate, polyimide, polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, tetrafluoroethylene And a copolymer obtained by copolymerizing a monomer mixture containing at least one comonomer, a fluorine-containing copolymer having a cyclic structure in the copolymer main chain, a water-absorbing substance having a water absorption of 1% or more, a water absorption of 0 .1% or less of moisture-proof substances and the like.

  There is no particular limitation on the method for forming the protective layer. For example, vacuum deposition, sputtering, reactive sputtering, MBE (molecular beam epitaxy), cluster ion beam, ion plating, plasma polymerization (high frequency excitation ions) Plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method, printing method, and transfer method can be applied.

The light-emitting element of the present invention can improve the light extraction efficiency by various known devices. For example, by processing the substrate surface shape (for example, forming a fine concavo-convex pattern), controlling the refractive index of the substrate / ITO layer / organic layer, controlling the film thickness of the substrate / ITO layer / organic layer, etc. It is possible to improve light extraction efficiency and external quantum efficiency.

  The light-emitting element of the present invention may be a so-called top emission type in which light emission is extracted from the anode side.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to this.

Example 1
Synthesis of Compound A-1 Under a nitrogen stream, 20 g of 1,4-dibromobenzene and 100 ml of dehydrated diethyl ether were ice-cooled, and 55 ml of a 1.6 mol / l normal butyl lithium / hexane solution was added dropwise over 20 minutes. After completion of the dropwise addition, the ice bath was removed, the temperature was raised to room temperature, and the mixture was further stirred. After 30 minutes, the mixture was ice-cooled again, and 10.7 g of dichlorodiphenylsilane was added dropwise over 30 minutes. After completion of the addition, the temperature was raised to room temperature and stirring was continued. Three hours later, 90 ml of a 1.0 mol / l hydrochloric acid aqueous solution was added dropwise, and after completion of the dropwise addition, 200 ml of chloroform and 100 ml of water were further added. The organic layer obtained by liquid separation was washed with water, dried over magnesium sulfate and filtered, and then the solvent was distilled off under reduced pressure. The obtained white solid was recrystallized from a chloroform / methanol mixed solvent to obtain 15.0 g (yield 71%) of Compound A-1.

Example 2
Synthesis of Exemplary Compound (1-1) 2.6 g of Compound A-1 synthesized in Example 1 under a nitrogen stream, 1.8 g of carbazole, 0.08 g of palladium acetate, 4.1 g of rubidium carbonate, tris-t-butyl 0.24 g of phosphine and 50 ml of xylene were heated to reflux and stirred for 3 hours. The progress of the reaction was monitored by TLC (thin layer chromatography), and after confirming the disappearance of Compound A, 50 ml of chloroform and 50 ml of water were added to the reaction mixture, followed by liquid separation. The obtained organic layer was dried over magnesium sulfate and filtered, and then the solvent was distilled off under reduced pressure. The obtained solid was purified by column chromatography (hexane / chloroform), and then recrystallized from a mixed solvent of hexane / chloroform to obtain 2.6 g (yield 75%) of Exemplary Compound 1-1. The melting point of compound (1-1) was 274 ° C.

Example 3
Synthesis of Compound B Compound B is described as Exemplified Compound (1-1) in JP-A No. 2001-97953 and could be synthesized by the method described in this document.

Example 4
Synthesis of Exemplary Compound (2-1) Under a nitrogen stream, 5.0 g of Compound A-1 synthesized in Example 1, 5.4 g of Compound B synthesized in Example 2, 0.11 g of palladium diacetate, Tris-t- 0.31 g of butylphosphine, 3.9 g of t-butoxy sodium and 100 ml of xylene were heated to reflux and stirred for 3 hours. The progress of the reaction was monitored by TLC (Thin Layer Chromatography), and after confirming the disappearance of Compound A, 100 ml of chloroform and 100 ml of water were added to the reaction mixture for liquid separation. The obtained organic layer was dried over magnesium sulfate and filtered, and then the solvent was distilled off under reduced pressure. The obtained solid was purified by column chromatography (hexane / chloroform) and then recrystallized from a mixed solvent of hexane / chloroform to obtain 4.8 g (yield 58%) of Exemplary Compound (2-1). The melting point of the compound (2-1) was 364 ° C.

Example 5
Evaluation of Reversibility of Oxidation Wave by CV (Cyclic Voltammetry) This example was performed to evaluate the stability of the compound of the present invention in an EL device.
When the EL element is driven, it can be considered that the organic compound material in the element is constantly oxidized or reduced by charge injection and transport of holes or electrons. Therefore, it is effective to measure the CV of the organic compound material as one method for evaluating the stability of the organic compound material when the element is driven.

  That is, if the oxidation wave or reduction wave obtained by the CV method is reversible, the organic compound material is stable against oxidation or reduction, and further changes in the oxidation wave or reduction wave from the initial waveform when the sweep is repeated. Is small, it can be judged that the material is more stable against oxidation or reduction.

  This time, in order to evaluate the oxidation stability of the material in particular, the reversibility evaluation of the oxidation wave under the following CV measurement conditions and the waveform change from the first sweep by repeated sweep were measured.

CV measurement and measurement conditions Support electrolyte: ⁿ Bu ₄ N · PF ₆ (0.1 M)
Working electrode: Pt
Counter electrode: Pt
Reference electrode: SCE
Sweep speed: 100 mV / s
Measuring range: 0 to +1.6 V vs. SCE
1.0 mM with Benzene-acetonitrile (1: 1) mixed solvent as sample solution
Prepare the solution. After preparation, the solution was filtered through a membrane filter and subjected to Ar bubbling and then measured.
The results are shown in the table below.

  As described above, it was found that the compound (1-1) of the present invention had better oxidation wave reversibility by the CV method and smaller waveform change due to repeated sweeps than the compound of the comparative example. This result shows that the oxidation stability of the compound of the present invention is high, that is, suggests that an EL device prepared using this compound exhibits excellent driving durability.

Example 6
The cleaned ITO substrate is put in a vapor deposition apparatus, and copper phthalocyanine is first deposited as a hole injection layer to a thickness of 10 nm, and α-NPD (N, N′-diphenyl-N, N′-di (α -Naphthyl) -benzidine) was evaporated 30 nm. On top of this, exemplary compound (1-1) and Ir (ppy) ₃ were co-deposited in a ratio of 9: 1 (weight ratio) to a thickness of 30 nm, and BAlq was deposited thereon to 10 nm, followed by 40 nm of Alq3. . A patterned mask (a mask with a light emission area of 4 mm x 5 mm) is placed on the organic thin film, lithium fluoride is deposited in a thickness of about 1 nm in a deposition apparatus, and aluminum is deposited on the film in a thickness of about 200 nm to produce a device. did. Using a source measure unit 2400 type manufactured by Toyo Technica, applying a constant DC voltage to the EL element to emit light, using a luminance meter BM-8 from Topcon and a spectrum analyzer PMA-11 from Hamamatsu Photonics. Measured.
As a result, green light emission with a chromaticity value (0.27, 0.62) was obtained, and the external quantum efficiency of the device was 7.5%. When the durability evaluation of this element is performed at an initial luminance of 2000 cd / m ² and a constant current value, the luminance half time is about 800 hours.

Example 7
The device was evaluated in the same manner as in Example 6 using Compound (2-1) instead of NPD and CBP instead of Compound (1-1).
As a result, green light emission with a chromaticity value (0.26, 0.61) was obtained, and the external quantum efficiency of the device was 7.2%. When the durability evaluation of this element is performed at an initial luminance of 2000 cd / m ² and a constant current value, the luminance half time is about 700 hours.

Comparative Example 1
An element was prepared and evaluated in the same manner as in Example 6 using CBP instead of the compound (1-1).
As a result, green light emission of chromaticity (0.27, 0.62) was obtained, and the external quantum efficiency of the device was 6.0%. When the durability evaluation of this element is performed with an initial luminance of 2000 cd / m ² and a constant current value, the luminance half time is about 400 hours.

Comparative Example 2
An element was prepared and evaluated in the same manner as in Example 6 using Compound C described in Patent Document 1 instead of Compound (1-1). As a result, green light emission of chromaticity (0.27, 0.62) was obtained, and the external quantum efficiency of the device was 5.0%. When the durability evaluation of this element is performed at an initial luminance of 2000 cd / m ² and a constant current value, the luminance half time is about 200 hours.
Similarly, a high-efficiency light-emitting element can be produced using other compounds of the present invention.

Claims (6)

An organic electroluminescent device having at least one organic layer including a light emitting layer between a pair of electrodes, wherein the organic layer includes at least one compound represented by the following general formula (1). .

(In the formula, R ¹¹ and R ¹² each independently represents an aryl group or a heteroaryl group. When R ¹¹ and R ¹² are phenyl groups, nitrogen-containing heterocycles are substituted on R ¹¹ and R ¹² as substituents. (Ar ¹¹ and Ar ¹² each independently represent a group represented by the general formula (2).)

(In the formula, Ar ²¹ represents an arylene group or a heteroarylene group, R ²¹ , R ²² , R ²³ , and R ²⁴ each independently represent a substituent or a hydrogen atom. L ² represents a substituted or unsubstituted o- Arylene, vinylene, -NR- (R represents a substituent), -O-, or -S-, and m represents 0 or 1.) The organic electroluminescent device according to claim 1, wherein, in the general formula (1), R ¹¹ and R ¹² are an unsubstituted aryl group or an unsubstituted heteroaryl group.   The organic electroluminescent element according to claim 1, wherein m is 0 in the general formula (2). In general formula (2), m is 1 and the organic electroluminescence device according to claim 1 or 2 L ² is a substituted or unsubstituted o- arylene or vinylene. The organic electroluminescent device according to claim 1, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (3) or the general formula (4).

(In the formula, R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ , R ³⁶ , R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ are each independently an alkyl group, an aryl group, A, b, g and h each independently represents an integer of 0 to 4, c and d each independently represents an integer of 0 to 8; Each independently represents an integer of 0 to 2. e, f, k, l each independently represents an integer of 0 to 5) The compound represented by General formula (3) or General formula (4).

(In the formula, R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ , R ³⁶ , R ⁴¹ , R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ are each independently an alkyl group, an aryl group, A, b, g and h each independently represents an integer of 0 to 4, c and d each independently represents an integer of 0 to 8; Each independently represents an integer of 0 to 2. e, f, k, l each independently represents an integer of 0 to 5)