JP2005276788A - Organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent element with excellent luminescence properties, element drive durability, and preservation stability. <P>SOLUTION: The organic electroluminescent element has at least an organic layer including luminescent layer between a pair of electrodes. The organic electroluminescent element includes at least one of chemical compounds expressed by the following general formula 1 in the organic layer. In the formula, RR<SB>11</SB>represents substituent which may be same or different from each other and m represents an integer from 0 to 4. R<SB>12</SB>represents vinylene or arylene base which may be same or different from each other and n represents an integer equal to or larger than 1. <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.

  Research and development on various display elements are active today, and organic electroluminescence (EL) elements (sometimes referred to as light-emitting elements, EL elements, or light-emitting elements of the present invention) have low voltage and high luminance. Since it can emit light, it is attracting attention as a promising display element.

  Since the aromatic fused ring compound used in the EL device has high charge transport performance and chemical stability, it is known that a device using the aromatic fused compound is advantageous in terms of light emission characteristics and device durability.

However, these aromatic condensed compounds generally have a low T ₁ (minimum triplet excitation energy level). For this reason, if these are used in phosphorescent organic electroluminescence devices, the triplet state of the luminescent material is deactivated, and the luminous efficiency is remarkably lowered. For this reason, an aromatic hydrocarbon compound applicable to a phosphorescent organic electroluminescence device has been demanded.

Non-Patent Document 1 discloses a compound (cyclophane derivative) included in the present invention, but there is no description or suggestion of using the compound for an organic electroluminescence device.
Journal of American Chemical Society, 115, 3511-3518 (1993)

  An object of the present invention is to provide an organic electroluminescent device having good light emission characteristics, device driving durability, and storage stability.

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 at least one compound represented by the following general formula (1) is contained in the organic layer. Organic electroluminescent element to contain.
(In the formula, R ¹¹ represents a substituent which may be the same or different, and m represents an integer of 0 to 4. R ¹² represents a vinylene or arylene group which may be the same or different, and n represents Represents an integer of 1 or more.)

［２］前記一般式（１）で表される化合物が、下記一般式（２）で表される化合物である請求項1に記載の有機電界発光素子。
（式中、Ｒ²¹は互いに同じでも異なっていてもよい置換基を表し、ｐは０から４の整数を表す。Ｒ²²、Ｒ²³、Ｒ²⁴は互いに同じでも異なっていてもビニレンもしくはアリーレン基を表す。）

[2] The organic electroluminescence device according to claim 1, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (2).
(In the formula, R ²¹ represents a substituent which may be the same or different, and p represents an integer of 0 to 4. R ²² , R ²³ and R ²⁴ may be vinylene or arylene groups which may be the same or different. Represents.)

［３］前記一般式（２）において、Ｒ²²、Ｒ²³、Ｒ²⁴が置換もしくは無置換のフェニレン基である［２］に記載の有機電界発光素子。
［４］前記一般式（２）で表される化合物が、下記一般式（３）で表される請求項２又は３に記載の有機電界発光素子。
（式中、Ｒ³¹、Ｒ³²、Ｒ³³、Ｒ³⁴は互いに同じでも異なっていてよい置換基を表し、ｑ、ｒ、ｓ、ｔはそれぞれ独立に０から４までの整数を表す。）

[3] The organic electroluminescence device according to [2], wherein in the general formula (2), R ²² , R ²³ and R ²⁴ are substituted or unsubstituted phenylene groups.
[4] The organic electroluminescent element according to claim 2 or 3, wherein the compound represented by the general formula (2) is represented by the following general formula (3).
(In the formula, R ³¹ , R ³² , R ³³ and R ³⁴ represent the same or different substituents, and q, r, s and t each independently represent an integer of 0 to 4.)

［５］前記一般式（１）乃至一般式（３）で表される化合物を前記発光層に少なくとも１種含有する［１］〜［４］のいずれか一に記載の有機電界発光素子。
［６］前記発光層にさらにりん光発光材料を含有する［５］に記載の有機電界発光素子。

[5] The organic electroluminescent element according to any one of [1] to [4], wherein the light emitting layer contains at least one compound represented by the general formula (1) to the general formula (3).
[6] The organic electroluminescent element according to [5], wherein the light emitting layer further contains a phosphorescent material.

  According to the present invention, an organic electroluminescent device having excellent light emission characteristics, device driving durability, and storage stability can be obtained. The light emitting device of the present invention is excellent in light emitting characteristics, durability and storage stability.

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 at least one compound represented by the following general formula (1) is contained in the organic layer. The present invention relates to an organic electroluminescent device containing
(In the formula, R ¹¹ represents a substituent which may be the same or different, and m represents an integer of 0 to 4. R ¹² represents a vinylene or arylene group which may be the same or different, and n represents Represents an integer of 1 or more.)

The general formula (1) will be described in detail. In general formula (1), R ¹¹ represents a substituent which may be the same as or different from each other. The following substituent A is mentioned as a substituent.

(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 it is C7-30, More preferably, it is C7-20, Most preferably, it is C7-12, for example, phenyloxycarbonyl etc. are mentioned. ), An acyloxy group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms such as acetoxy and benzoyloxy), an acylamino group (preferably 2-30 carbon atoms, more preferably 2-20 carbon atoms, particularly preferably 2-10 carbon atoms, and examples thereof include acetylamino, benzoylamino, and the like, and an alkoxycarbonylamino group (preferably having 2-2 carbon atoms). 30, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonylamino, etc.), aryloxycarbonylamino group (preferably 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonyl And sulfonylamino groups (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, such as methanesulfonylamino and benzenesulfonylamino). ), A sulfamoyl group (preferably having 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms, particularly preferably 0 to 12 carbon atoms, such as sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenyl Sulfamoyl, etc.), a carbamoyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as carbamoyl, methylcarbamoyl, diethylcarbamoyl, Phenylcarbamoyl etc.), alkylthio group ( Preferably, it has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include methylthio, ethylthio and the like, and an arylthio group (preferably 6 to 30 carbon atoms). , More preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio, and the like, a heteroarylthio group (preferably 1 to 30 carbon atoms, more preferably 1 to carbon atoms). 20, particularly preferably 1 to 12 carbon atoms, such as pyridylthio, 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio and the like, and a sulfonyl group (preferably having a carbon number). 1-30, More preferably, it is C1-C20, Most preferably, it is C1-C12, for example, mesyl, tosyl, etc. are mentioned. ), A sulfinyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfinyl, benzenesulfinyl, etc.), a ureido group (preferably Has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include ureido, methylureido, phenylureido and the like, and a phosphoric acid amide group (preferably carbon). 1 to 30, 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 (Eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nito Group, hydroxamic acid 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 a nitrogen atom, an oxygen atom, Sulfur atom, specifically, for example, imidazolyl, pyridyl, quinolyl, furyl, thienyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, carbazolyl group, azepinyl group, etc.), silyl group (preferably carbon 3 to 40, more preferably 3 to 30 carbon atoms, particularly preferably 3 to 24 carbon atoms, and examples thereof include trimethylsilyl and triphenylsilyl).

R ¹¹ is preferably an alkyl group, an aryl group, or a heteroaryl group, more preferably an aryl group or a heteroaryl group, and most preferably a phenyl group.

  m represents an integer of 0 to 4, preferably 0 to 2, and more preferably 0 or 1.

R ¹² represents a vinylene or arylene group which may be the same or different from each other. R ¹² is preferably an arylene group, more preferably an orthophenylene group, a metaphenylene group, or a paraphenylene group, and still more preferably an orthophenylene group or a paraphenylene group.

R ¹² may further have a substituent, and examples of the substituent are the same as those in the case of R ¹¹ , and the preferred range is also the same.

  n represents an integer of 1 or more. n is preferably 2 or more and 5 or less, more preferably 2 or more and 4 or less, and even more preferably 3.

  Next, general formula (2) will be described.

（式中、Ｒ²¹は互いに同じでも異なっていてもよい置換基を表し、ｐは０から４の整数を表す。Ｒ²²、Ｒ²³、Ｒ²⁴は互いに同じでも異なっていてもよく、ビニレンもしくはアリーレン基を表す。）

(In the formula, R ²¹ represents a substituent which may be the same as or different from each other, and p represents an integer of 0 to 4. R ²² , R ²³ and R ²⁴ may be the same as or different from each other, vinylene or Represents an arylene group.)

In the general formula (2), R ²¹ represents a substituent which may be the same as or different from each other. Examples of the substituent are the same as those for R ¹¹ , and the preferred ranges are also the same.

  p represents an integer of 0 to 4, preferably 0 to 2, and more preferably 0 or 1.

R ²² , R ²³ and R ²⁴ may be the same or different and each represents a vinylene or arylene group. R ²² , R ²³ , and R ²⁴ are preferably arylene groups, more preferably orthophenylene groups, metaphenylene groups, and paraphenylene groups, R ²² and R ²⁴ are orthophenylene groups, and R ²³ is a paraphenylene group. Most preferred.

R ²² , R ²³ and R ²⁴ may have a substituent, and examples of the substituent are the same as those for R ¹¹ . R ²² , R ²³ , and R ²⁴ may preferably have an alkyl group, an aryl group, a heteroaryl group, or a substituent that combines with each other to form an aromatic ring, and more preferably an aryl group, a hetero group An aryl group is a substituent that is bonded to each other to form an aromatic ring, and most preferably a phenyl group is a substituent that is bonded to each other to form an aromatic ring.

  Next, general formula (3) will be described.

（式中、Ｒ³¹、Ｒ³²、Ｒ³³、Ｒ³⁴は互いに同じでも異なっていてよい置換基を表し、ｑ、ｒ、ｓ、ｔはそれぞれ独立に０から４までの整数を表す。）

(In the formula, R ³¹ , R ³² , R ³³ and R ³⁴ represent the same or different substituents, and q, r, s and t each independently represent an integer of 0 to 4.)

R ³¹ , R ³² , R ³³ and R ³⁴ represent the same or different substituents. Examples of the substituent are the same as those for R ¹¹ , and the preferred ranges are also the same.

  q, r, s, and t each independently represent an integer of 0 to 4, preferably 0 to 2, and more preferably 0 or 1.

  The compound represented by the general formula (1), the general formula (2) or the general formula (3) may be a low molecular compound, and an oligomer compound or a polymer compound (weight average molecular weight (polystyrene conversion) is preferable. 1000 to 5000000, more preferably 2000 to 1000000, and still more preferably 3000 to 100,000. In the case of the polymer compound, the structure represented by the general formula (1), the general formula (2), or the general formula (3) may be included in the polymer main chain, or may be included in the polymer side chain. Also good. In the case of a polymer compound, it may be a homopolymer compound or a copolymer. The compound represented by general formula (1), general formula (2) or general formula (3) is preferably a low molecular compound.

  Although the example of a compound represented by General formula (1), General formula (2) or General formula (3) below is shown, this invention is not limited to these.

  A method for producing the compound represented by the general formula (1), the general formula (2) or the general formula (3) will be described. The compound represented by the general formula (1), the general formula (2), or the general formula (3) can be synthesized by, for example, the method described in Non-Patent Document 1.

  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 represented by the general formula (1), the general formula (2), or the general formula (3), 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 represented by the general formula (1), the general formula (2), or the general formula (3) and the organic layer to be contained are not particularly limited. It is preferably contained in the light emitting layer, more preferably contained in the light emitting layer, and further preferably contained in the light emitting layer as a host material.

In the light emitting device of the present invention, the organic layer preferably contains a compound represented by the general formula (1), the general formula (2), or the general formula (3) as a main component. When the compound represented by the general formula (1), the general formula (2), or the general formula (3) is included in the hole transport layer, the general formula (1), the general formula (2), or the general formula (3) The content of the compound represented is 100% of the total layer mass of the hole transport material,
It is preferably 20% by mass or more and 100% by mass or less,
More preferably 50% by mass or more and 100% by mass or less,
More preferably, it is 70 mass% or more and 100 mass% or less.
On the other hand, when the compound represented by general formula (1), general formula (2) or general formula (3) is contained in the light emitting layer, general formula (1), general formula (2) or general formula (3) The content of the compound represented by the formula is as follows:
It is preferably 20% by mass or more and 100% by mass or less,
More preferably, it is 50 mass% or more and 99 mass% or less,
More preferably, it is 70 mass% or more and 95 mass% or less.

  The light-emitting material contained in the light-emitting element of the present invention may be a fluorescent compound or a phosphorescent compound. 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 derivatives thereof, Coumarin and derivatives thereof, condensed aromatic compounds, perinone and derivatives thereof, oxadiazole and derivatives thereof, oxazine and derivatives thereof, aldazine and derivatives thereof, pyraridine and derivatives thereof, cyclopentadiene and derivatives thereof, bisstyrylanthracene and derivatives thereof, Quinacridone and its derivatives, pyrrolopyridine and its derivatives, thiadiazolopyridine and its derivatives, cyclopentadiene and its derivatives, styrylamine and Derivatives thereof, diketopyrrolopyrrole and derivatives thereof, aromatic dimethylidin compounds, metal complexes of 8-quinolinol and derivatives thereof, metal complexes of pyromethene and derivatives thereof, various metal complexes represented by rare earth complexes, transition metal complexes, and the like, polythiophene , Polymer compounds such as polyphenylene and polyphenylene vinylene, organic silanes and derivatives thereof, compounds represented by general formula (1), general formula (2), or general formula (3). The light-emitting material is preferably a condensed aromatic compound, a quinacridone derivative, a diketopyrrolopyrrole derivative, a metal complex of a pyromethene derivative, a rare earth complex, or a transition metal complex, and more preferably a condensed aromatic compound or a transition metal complex.

  In the light emitting device of the present invention, the light emitting material is preferably a phosphorescent light emitting compound from the viewpoint of luminous efficiency. The phosphorescent compound is particularly preferably a transition metal complex. 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 foundation and application of organometallics” written by Akio Yamamoto, pages 150 and 232, Houhuabosha (1982) and H.H. Yersin's “Photochemistry and Photophysics of Coordination Compound”, pages 71 to 77 and pages 135 to 146, Springer-Verlag (1987), etc.

  The phosphorescent material preferably has a phosphorescence 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 light-emitting 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. / 15645 A1, Japanese Patent Application Laid-Open 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. 2001-239684, Japanese Patent Application No. 2001-239281, Japanese Patent Application No. 2001-219909, EP 12112257, JP 2002-226495, JP 2002-234894, JP 2001-247659, JP 2001-298470, JP 2002-173684, JP 2002-203678, JP 2002-203 679 et al., Nature, 395, 151 (1998), Applied Physics Letters, 75, 4 (1999), Polymer Preprints, 41, 770 (2000), Journal of American Chemical. Those described in non-patent literature such as Society, 123, 4304 (2001), Applied Physics Letters, 79, 2082 (1999) can be suitably used.

  The formation method of the organic layer of the light emitting device containing the compound represented by the general formula (1), the general formula (2), or the general formula (3) is not particularly limited, but resistance heating evaporation, electron beam , Sputtering, molecular lamination method, coating method, ink jet method, printing method and the like are used, and resistance heating vapor deposition, coating method, and transfer method are preferable in terms of characteristics and production.

  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 fluorides or oxides thereof, 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 thereof. The cathode can take not only a single layer structure of the compound and the mixture but also a laminated structure including 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 the cathode is preferably low, and is preferably several hundred Ω / □ or less.

  The material of the light emitting layer is a function capable of injecting 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. For example, benzoxazole, benzimidazole, benzothiazole, Styrylbenzene, polyphenyl, diphenylbutadiene, tetraphenylbutadiene, naphthalimide, coumarin, perylene, perinone, oxadiazole, aldazine, pyralidine, cyclopentadiene, bisstyrylanthracene, quinacridone, pyrrolopyridine, thiadiazolopyridine, cyclopentadiene, Styrylamine, aromatic dimethyl Lidin compounds, various metal complexes represented by 8-quinolinol metal complexes and rare earth complexes, polymer compounds such as polythiophene, polyphenylene, and polyphenylene vinylene, organic silanes, iridium trisphenylpyridine complexes, and transitions represented by platinum porphyrin complexes Examples thereof include metal complexes and derivatives thereof.

At least one of the materials of the light emitting layer is preferably 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 represented by general formula (1), general formula (2), or general formula (3), and derivatives thereof. The film thicknesses of the hole injection layer and the hole transport layer are not particularly limited, but are usually preferably in the range of 1 nm to 5 μm, more preferably 5 nm to 1 μm, and still more preferably 10 nm to 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 ring tetracarboxylic acid anhydride, metal complexes of phthalocyanine, 8-quinolinol, metal phthalocyanines, metal complexes having benzoxazole and benzothiazole as ligands, organic silanes, general formula (1), general Examples thereof include compounds represented by formula (2) or general formula (3), and derivatives thereof. Although the film thickness of an electron injection layer and an electron carrying layer is not specifically limited, The thing of the range of 1 nm-5 micrometers is preferable normally, 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 and TiO ₂ , metal fluorides such as MgF ₂ , LiF, AlF ₃ , and 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.

  Specific examples of the present invention will be described below, but the embodiments of the present invention are not limited thereto.

(Example 1)
The cleaned ITO substrate is put into a vapor deposition apparatus, and copper phthalocyanine is first deposited as a hole injection material 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, compound (1-2) and compound a were co-deposited at a ratio of 20: 1 (weight ratio) to a thickness of 30 nm, on which Balq was deposited 10 nm, and further Alq 3 was deposited 40 nm. 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 6.1%.
Further, when the element durability of this element is evaluated at an initial luminance of 2000 cd / m ² and a constant current value, the luminance half time is about 1500 hours.

(Example 2)
Using the compound (1-11) and the compound b instead of the compound (1-2), the device was evaluated in the same manner as in Example 1. As a result, green light emission with a chromaticity value (0.26, 0.63) was obtained, and the external quantum efficiency of the device was 7.1%.
When the element durability of this element is evaluated at an initial luminance of 2000 cd / m ² and a constant current value, the luminance half time is about 1800 hours.

(Comparative Example 1)
The device C was evaluated in the same manner as in Example 1 except that the compound CBP was used instead of the compound (1-2). As a result, green light emission with a chromaticity value (0.27, 0.65) was obtained, and the external quantum efficiency of the device was 5.0%.
When the element durability of this element is evaluated at an initial luminance of 2000 cd / m ² and a constant current value, the luminance half time is about 800 hours.

(Example 3)
The cleaned ITO substrate is put into a vapor deposition apparatus, and copper phthalocyanine is first deposited as a hole injection material to a thickness of 10 nm, and α-NPD (N, N′-diphenyl-N, N′-di (α -Naphthyl) -benzidine) was evaporated to 40 nm. On top of this, compound (1-7) and compound c were co-evaporated to a thickness of 40 nm at a ratio of 50: 1 (weight ratio), and Alq3 was evaporated thereon to a thickness of 20 nm. 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. The EL device thus produced was caused to emit light in the same manner as in Example 1, and the luminance and emission wavelength were measured.
As a result, orange light emission with chromaticity (0.42, 0.54) was obtained, and the external quantum efficiency of the device was 1.6%.
When the element durability of this element is evaluated at an initial luminance of 2000 cd / m ² and a constant current value, the luminance half-life is about 2000 hours.

Similarly, a high-efficiency light-emitting element can be manufactured using a compound represented by another general formula (1), general formula (2), or general formula (3).

Claims (6)

An organic electroluminescence 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 represents a substituent which may be the same or different, and m represents an integer of 0 to 4. R ¹² represents a vinylene or arylene group which may be the same or different, and n represents Represents an integer of 1 or more.)

2. The organic electroluminescence device according to claim 1, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (2).
(In the formula, R ²¹ represents a substituent which may be the same or different, and p represents an integer of 0 to 4. R ²² , R ²³ and R ²⁴ may be vinylene or arylene groups which may be the same or different. Represents.)

The organic electroluminescent element according to claim 2, wherein, in the general formula (2), R ²² , R ²³ , and R ²⁴ are substituted or unsubstituted phenylene groups. The organic electroluminescent element according to claim 2 or 3, wherein the compound represented by the general formula (2) is represented by the following general formula (3).
(In the formula, R ³¹ , R ³² , R ³³ and R ³⁴ represent the same or different substituents, and q, r, s and t each independently represents an integer of 0 to 4.)

  The organic electroluminescent element as described in any one of Claims 1-4 which contains at least 1 type of the compound represented by the said General formula (1) thru | or General formula (3) in the said light emitting layer. The organic electroluminescent element according to claim 5, further comprising a phosphorescent material in the light emitting layer.