JP2006049716A - Organic electroluminescence element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescence element having a good luminous characteristic. <P>SOLUTION: The organic electroluminescence element is the one which has at least one organic layer between a pair of electrodes, and contains at least one kind of compound containing the structure represented by a general formula (1) as its partial structure. In the formula, each of R<SP>11</SP>and R<SP>12</SP>represents an alkyl group, an aryl group, a heteroaryl group, or a halogen atom; m1 represents the integer of 1 to 5; and further, m2 represents the integer of 0 to 9. m1+m2 is not smaller than 2. R<SP>11</SP>and R<SP>12</SP>may be identical with each other or different from each other. When m1 is not smaller than 2, a plurality of R<SP>11</SP>s may be identical with each other or different from each other. When m2 is not smaller than 2, a plurality of R<SP>12</SP>s may be identical with each other or different from each other. However, at least two of R<SP>11</SP>s and R<SP>12</SP>s whose summed number is m1+m2 must be fluorine atoms. <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. Among them, organic electroluminescence (EL) elements are attracting attention as promising display elements because they can emit light with high luminance at a low voltage.

  In the organic EL device, currently important technical issues are improvement of luminous efficiency and device durability. In order to improve the luminous efficiency and durability of the device, various aromatic condensed hydrocarbon materials have been proposed as suitable means. For example, Patent Document 1 discloses diphenylanthracene derivatives and EL devices using these. Patent Document 2 discloses a material having a rubrene skeleton and an EL element.

Although it has been found that the materials disclosed in the above patent documents and the devices using them are excellent in luminous efficiency, further improvement of these characteristics has been demanded.
Moreover, in the above aromatic fused ring hydrocarbon material, generally, as the π-conjugated system expands, the material is easily subjected to air oxidation. For this reason, there is a concern that the material deteriorates during handling at the time of creating an EL element, and the light emission characteristics of the element deteriorate.
JP-A-8-12600 Japanese Patent Laid-Open No. 10-289786

  An object of the present invention is to provide an organic electroluminescent device having good light emission characteristics.

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, and containing at least one compound including a structure represented by the following general formula (1) as a partial structure. An organic electroluminescent device characterized by that.

(Wherein R ¹¹ and R ¹² represent an alkyl group, an aryl group, a heteroaryl group, or a halogen atom, m1 represents an integer of 1 to 5, m2 represents an integer of 0 to 9, and m1 + m2 represents 2) R ¹¹ and R ¹² may be the same or different from each other, and when m1 is 2 or more, the plurality of R ¹¹ may be the same or different, and when m2 is 2 or more, the plurality of R ¹² are (It may be the same or different from each other, provided that at least two of m1 + m2 R ¹¹ and R ¹² are fluorine atoms.)
<2> The organic electroluminescent element as described in <1>, wherein the structure represented by the general formula (1) is represented by the following general formula (2).

(Wherein, R ² represents an alkyl group, an aryl group, a heteroaryl group, or a halogen atom,, n1 is .n1 one of R ² represents an integer of 2 to 5 may be the same as or different from each other, n1 pieces And at least two of R ^{2 in} the formula are fluorine atoms.)
<3> The organic electroluminescent element as described in <1>, wherein the structure represented by the general formula (1) is represented by the following general formula (3).

(Wherein, R ³ represents an alkyl group, an aryl group, a heteroaryl group, or a halogen atom,, p1 is .p1 amino R ³ represents an integer of 2 to 5 may be the same as or different from each other, p1 pieces At least two of R ^{3 in} the formula are fluorine atoms.)
<4> The organic electroluminescent element as described in <1>, wherein the compound containing the structure represented by the general formula (1) as a partial structure is represented by the general formula (4).

(In the formula, R ⁴¹ and R ⁴² represent an alkyl group, an aryl group, a heteroaryl group, or a halogen atom, and q 1 and q 2 each independently represent an integer of 2 to 5, but q 1 R ⁴¹ At least two, and at least two of q2 R ⁴² are fluorine atoms, R ⁴³ and R ^{44 each} represents an alkyl group, an aryl group, a heteroaryl group, or a halogen atom, and q3 and q4 are independent of each other. Represents an integer of 0 to 8.)
<5> The organic electroluminescent element as described in <1>, wherein the compound containing the structure represented by the general formula (1) as a partial structure is represented by the following general formula (5).

^{(Wherein, R 51,} and ^{R 52} is an alkyl group, an aryl group, a heteroaryl group, or a halogen atom,, r1, and r2 in independently of one another represent an integer of from 2 to 5, r1 amino ^{R 51} At least two and at least two of the r2 R ⁵² are fluorine atoms, R ⁵³ represents an alkyl group, an aryl group, a heteroaryl group, or a halogen atom, and r3 represents an integer of 0 to 10. r3 represents If 2 or more, r3 one R ⁵³ may be the same or different from each other.)

  The light emitting device of the present invention is excellent in light emission characteristics, device driving durability, and storage stability.

  One 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, the compound including a structure represented by the following general formula (1) as a partial structure It is an organic electroluminescent element containing at least one kind.

(Wherein R ¹¹ and R ¹² represent an alkyl group, an aryl group, a heteroaryl group, or a halogen atom, m1 represents an integer of 1 to 5, m2 represents an integer of 0 to 9, and m1 + m2 represents 2) R ¹¹ and R ¹² may be the same or different from each other, and when m1 is 2 or more, the plurality of R ¹¹ may be the same or different, and when m2 is 2 or more, the plurality of R ¹² are (It may be the same or different from each other, provided that at least two of m1 + m2 R ¹¹ and R ¹² are fluorine atoms.)

  The general formula (1) will be described.

In the formula, R ¹¹ and R ¹² represent an alkyl group, an aryl group, a heteroaryl group, or a halogen atom.

R ¹¹ and R ¹² may be the same as or different from each other. Further, when there are a plurality of R ¹¹ and R ¹² , R ¹¹ and R ¹² may be the same or different from each other. At least two of the plurality of R ¹¹ and R ¹² are fluorine atoms. Preferably R ^11, and three or more than five fluorine atoms of ^{R 12,} more preferably from 4 or 5 a fluorine atom of R ^{11, R 12,} of R ^{11, R 12} Most preferably, 5 of them are fluorine atoms.

When R ¹¹ or R ¹² is a substituent other than a fluorine atom, an alkyl group, an aryl group, or a heteroaryl group is preferable, an aryl group is more preferable, and a phenyl group is more preferable. Also, two R ¹² may form a ring structure.

  m1 represents an integer of 1 to 5. m1 is preferably an integer of 3 to 5, more preferably 4, 5, and most preferably 5.

  m2 represents an integer of 0 to 9. However, m1 + m2 is 2 or more. m2 is preferably an integer of 1 to 7, more preferably an integer of 1 to 4, and even more preferably 1 or 2.

  The structure represented by the general formula (1) is preferably represented by the general formula (2). Next, general formula (2) will be described.

(Wherein, R ² represents an alkyl group, an aryl group, a heteroaryl group, or a halogen atom,, n1 is .n1 one of R ² represents an integer of 2 to 5 may be the same as or different from each other, n1 pieces At least two of R ^{2 in} the formula are fluorine atoms.)

In the formula, R ² represents an alkyl group, an aryl group, a heteroaryl group, or a halogen atom.

n1 pieces of R ² may be the same as or different from each other, at least two of these is a fluorine atom. Preferably less five three or more of R ² is a fluorine atom, more preferably four or 5 of R ² is a fluorine atom, that five of the R ¹ is a fluorine atom is most preferable.

When R ² is a substituent other than a fluorine atom, an alkyl group, an aryl group, or a heteroaryl group is preferable, an aryl group is more preferable, and a phenyl group is more preferable.

  n1 represents an integer of 2 to 5, preferably 3 to 5, more preferably 4, 5, and most preferably 5.

  Moreover, it is preferable that the structure represented by General formula (1) is a structure represented by General formula (3).

(Wherein, R ³ represents an alkyl group, an aryl group, a heteroaryl group, or a halogen atom,, p1 is .p1 amino R ³ represents an integer of 2 to 5 may be the same as or different from each other, p1 pieces At least two of R ^{3 in} the formula are fluorine atoms.)

The general formula (3) will be described. In the formula, R ³ represents an alkyl group, an aryl group, a heteroaryl group, or a halogen atom.

The p1 R ³ groups may be the same as or different from each other, and at least two of these are fluorine atoms. Preferably less five three or more of R ³ is a fluorine atom, still more preferably 4 or 5 a fluorine atom of R ^3, be five of R ¹ is a fluorine atom is most preferable.

When R ³ is a substituent other than a fluorine atom, an alkyl group, an aryl group, or a heteroaryl group is preferable, an aryl group is more preferable, and a phenyl group is more preferable.

  p1 represents an integer of 2 to 5, preferably 3 to 5, more preferably 4, 5, and most preferably 5.

  The compound containing the structure represented by the general formula (1) as a partial structure is preferably represented by the general formula (4).

(In the formula, R ⁴¹ and R ⁴² represent an alkyl group, an aryl group, a heteroaryl group, or a halogen atom, and q 1 and q 2 each independently represent an integer of 2 to 5, but q 1 R ⁴¹ At least two, and at least two of q2 R ⁴² are fluorine atoms, R ⁴³ and R ^{44 each} represents an alkyl group, an aryl group, a heteroaryl group, or a halogen atom, and q3 and q4 are independent of each other. Represents an integer of 0 to 8.)

The general formula (4) will be described.
R ⁴¹ , R ⁴² , R ⁴³ , and R ⁴⁴ represent an alkyl group, an aryl group, a heteroaryl group, or a halogen atom.

R ⁴¹ and R ⁴² may be the same or different from each other, but at least two of q1 R ^{41 s} , and at least two of q2 R ^{42 s} are fluorine atoms. It is preferable that 3 or more and 5 or less of R ⁴¹ are fluorine atoms, and further 3 or more and 5 or less of R ⁴² are fluorine atoms, 4 or 5 of R ⁴¹ is a fluorine atom, and 4 of R ⁴² It is more preferable that one or five of them are fluorine atoms, and it is most preferable that five of R ⁴¹ are fluorine atoms and five of R ⁴² are fluorine atoms.

When R ⁴¹ and R ⁴² are a substituent other than a fluorine atom, an alkyl group, an aryl group, or a heteroaryl group is preferable, an aryl group is more preferable, and a phenyl group is more preferable.

R ⁴³ and R ⁴⁴ are preferably an alkyl group, an aryl group, or a heteroaryl group, more preferably an aryl group, and still more preferably a phenyl group.

  q1 and q2 each independently represent an integer of 2 to 5, preferably 3 to 5, more preferably 4, or 5, and most preferably 5.

  q3 and q4 represent an integer of 0 to 8, preferably 0 to 5, more preferably 0 to 3, more preferably 0 or 1, and most preferably 0.

  Moreover, it is preferable that the compound containing the structure represented by General formula (1) as a partial structure is represented by General formula (5).

^{(Wherein, R 51,} and ^{R 52} is an alkyl group, an aryl group, a heteroaryl group, or a halogen atom,, r1, and r2 in independently of one another represent an integer of from 2 to 5, r1 amino ^{R 51} At least two and at least two of the r2 R ⁵² are fluorine atoms, R ⁵³ represents an alkyl group, an aryl group, a heteroaryl group, or a halogen atom, and r3 represents an integer of 0 to 10. r3 represents If 2 or more, r3 one R ⁵³ may be the same or different from each other.)

  The general formula (5) will be described.

R ⁵¹ , R ⁵² , and R ⁵³ represent an alkyl group, an aryl group, a heteroaryl group, or a halogen atom.

R ^51, and ^{R 52} may be the same as or different from each other, at least two r1 amino ^{R 51,} at least two further r2 amino ^{R 52} is a fluorine atom. It is preferable that 3 or more and 5 or less of R ⁵¹ are fluorine atoms, and further 3 or more and 5 or less of R ⁵² are fluorine atoms, 4 or 5 of R ⁵¹ is a fluorine atom, and 4 of R ⁵² More preferably, one or five is a fluorine atom, most preferably five of R ⁵¹ are fluorine atoms, and most preferably five of R ⁵² are fluorine atoms.

When R ⁵¹ and R ⁵² are substituents other than a fluorine atom, an alkyl group, an aryl group, or a heteroaryl group is preferable, an aryl group is more preferable, and a phenyl group is more preferable.

R ⁵³ is preferably an alkyl group, an aryl group, or a heteroaryl group, more preferably an aryl group, and still more preferably a phenyl group. When R ⁵³ is 2 or more, the plurality of R ⁵³ may be the same as or different from each other.

  r1 and r2 each independently represents an integer of 2 to 5, preferably 3 to 5, more preferably 4, or 5, and most preferably 5.

  r3 represents an integer of 0 to 10, preferably 0 to 6, more preferably 0 to 4, more preferably 0 or 2, and most preferably 0.

  A compound containing a structure represented by general formula (1), general formula (2), or general formula (3) as a partial structure, or a compound represented by general formula (4) or general formula (5) is low. A molecular compound may be sufficient, and it is an oligomer compound and a polymer compound (The weight average molecular weight (polystyrene conversion) becomes like this. Preferably it is 1000-5 million, More preferably, it is 2000-1 million, More preferably, it is 3000-100000). Also good. In the case of a 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 of the present invention is preferably a low molecular compound.

  In the present invention, the “partial structure” means, for example, a structure in which at least one or two or more hydrogen atoms are removed from the structure and the structure is present as a partial structure in the compound.

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

  Next, the organic electroluminescence (EL) element of the present invention will be described. The light-emitting element of the present invention is not particularly limited as long as it is an element that uses a compound having the structure represented by the general formula (1) as a partial structure, such as a system, a driving method, and a usage form.

  In the light-emitting element of the present invention, a compound containing a structure represented by the general formula (1), the general formula (2), or the general formula (3) as a partial structure, or the general formula (4) or the general formula (5). It is sufficient that the compound represented by the formula is contained in at least one of the organic layers of the light emitting element, but is preferably contained in the light emitting layer or the electron transport layer, and is contained in the light emitting layer as a light emitting material or a host material. More preferably. When the light-emitting element of the present invention contains phosphorescence, the compound is preferably used as a host material and / or an electron transport material.

A compound containing a structure represented by general formula (1), general formula (2), or general formula (3) as a partial structure, or a compound represented by general formula (4) or general formula (5) emits light. When it is contained in the layer as a light emitting material, it is preferably 0.1% by mass or more and 100% by mass or less, more preferably 0.5% by mass or more and 50% by mass or less in the light emitting layer. More preferably, it is 10 mass% or less.
In addition, a compound containing a structure represented by general formula (1), general formula (2), or general formula (3) as a partial structure, or a compound represented by general formula (4) or general formula (5) Is contained as a host material in the light emitting layer, it is preferably 10% by mass to 99% by mass in the light emitting layer, more preferably 30% by mass to 99% by mass, and more preferably 50% by mass to 97% by mass. More preferably, it is at most mass%.

  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, or transfer method is 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 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 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 and polyphenylene vinylene, organic silanes, iridium trisphenylpyridine complexes, and platinum porphyrin complexes Transition metal complexes and derivatives thereof.

  The light emitting material contained in the light emitting device of the present invention may be either a fluorescent light emitting compound or a phosphorescent light emitting 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 their derivatives, coumarin and their derivatives, condensed aromatic compounds, perinone 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 Examples include metal complexes of these derivatives, pyromethene and metal complexes of those derivatives, various metal complexes represented by rare earth complexes, transition metal complexes, polymer compounds such as polythiophene, polyphenylene, polyphenylene vinylene, organic silanes, and derivatives thereof. It is done. The light-emitting material is preferably a condensed aromatic compound, quinacridone and a derivative thereof, diketopyrrolopyrrole and a derivative thereof, a metal complex, a rare earth complex, or a transition metal complex of pyromethene and a derivative thereof, and more preferably a condensed aromatic compound. Compound or transition metal complex.

  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 formation method of the light emitting layer is not particularly limited. For example, resistance heating vapor deposition, electron beam, sputtering, molecular lamination method, coating method (spin coating method, casting method, dip coating method, etc.), inkjet method, Methods such as printing, LB, and transfer are used, and resistance heating vapor deposition or coating is preferred.

  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. Especially 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 thereof include silane derivatives, carbon films, compounds of the present invention, 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, for example, 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 method). Coating method, etc.), ink-jet method, printing method, and transfer method. 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 or benzothiazole as ligands, organic silanes, compounds of the present invention, and Examples thereof include 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, for example, 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 inkjet 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 also 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) (Ion plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method, printing method, transfer method can be applied.

  The light emitting device of the present invention can improve the light extraction efficiency by various known methods. 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.

  Hereinafter, the present invention will be described in more detail based on examples.

Reference example 1
Measurement of Relative Fluorescence Quantum Yield Relative fluorescence quantum yield of Exemplified Compound (2-1) in the solution was measured in order to evaluate the performance of the material used for the device of the present invention. In general, a material having a high fluorescence quantum yield gives high external quantum efficiency when used as a light emitting material in an EL device.
Measurement was performed in degassed dichloroethane under an argon atmosphere, and rhodamine 101 was used as a standard. Similarly, rubrene was also measured as a comparative example.
Furthermore, after the measurement was completed for any of the samples, the fluorescence quantum yield was measured again after releasing the air and leaving it for 2 hours. The deterioration of the material due to air oxidation can be observed as a decrease in relative fluorescence quantum yield. That is, the stability of each compound against air oxidation can be evaluated by comparing the relative quantum yields before and after air release. The results are shown in the table below.

From the results in the above table, it is clear that the compound of the present invention has a higher fluorescence quantum yield than rubrene, which is a comparative compound.
Further, focusing on the relative quantum yield after air release, in the case of rubrene, the relative quantum efficiency after air release is markedly decreased, but in the case of compound (2-1), the relative fluorescence after air release is relatively low. The decrease in quantum yield is greatly reduced. From this, it is clear that the oxidation stability of the compound of the present invention is greatly improved.

  From the above results, it is suggested that the EL device of the present invention containing the above compound exhibits high external quantum efficiency. Furthermore, since the above compound used as a light emitting material is highly stable against air oxidation, the light emitting device of the present invention is deteriorated in device performance due to reduction of material deterioration during handling at the time of device fabrication, and variation in performance between devices. Can be suppressed.

Example 1
Preparation of Light-Emitting Element The cleaned ITO substrate is put into a vapor deposition apparatus, and first, copper phthalocyanine is deposited as a hole injection layer to a thickness of 10 nm, and α-NPD (N, N′-diphenyl-N, N ′) is used as a hole transport material thereon. -Di ([alpha] -naphthyl) -benzidine) was evaporated to 50 nm. On top of this, the exemplified compound (1-2) and the following compound a were co-deposited in a 50: 1 ratio (mass ratio) to a thickness of 40 nm, and the following compound b was deposited thereon by 30 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 vapor deposition device at about 1 nm, and aluminum is deposited on the film to a thickness of about 200 nm to produce a device. did. Using a source measure unit model 2400 made by Toyo Technica, applying a DC constant 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, red light emission having a chromaticity value (0.60, 0.39) was obtained, and the external quantum efficiency of the device was 2.5%.

Comparative Example 1
A device was prepared in the same manner as in Example 1 using the compound c described in JP-A-8-12600 instead of the exemplified compound (1-2). As a result, red light emission having a chromaticity value (0.58, 0.40) was obtained, and the external quantum efficiency of the device was 1.1%.

  In addition, as in Example 1, a high-efficiency light-emitting element could be produced using other compounds of the present invention.

Claims (5)

An organic electroluminescence device having at least one organic layer between a pair of electrodes, the organic electroluminescence device comprising at least one compound containing a structure represented by the following general formula (1) as a partial structure: Light emitting element.

(Wherein R ¹¹ and R ¹² represent an alkyl group, an aryl group, a heteroaryl group, or a halogen atom, m1 represents an integer of 1 to 5, m2 represents an integer of 0 to 9, and m1 + m2 represents 2) R ¹¹ and R ¹² may be the same or different from each other, and when m1 is 2 or more, the plurality of R ¹¹ may be the same or different, and when m2 is 2 or more, the plurality of R ¹² are (It may be the same or different from each other, provided that at least two of m1 + m2 R ¹¹ and R ¹² are fluorine atoms.) The organic electroluminescent element according to claim 1, wherein the structure represented by the general formula (1) is represented by the following general formula (2).

(Wherein, R ² represents an alkyl group, an aryl group, a heteroaryl group, or a halogen atom,, n1 is .n1 one of R ² represents an integer of 2 to 5 may be the same as or different from each other, n1 pieces At least two of R ^{2 in} the formula are fluorine atoms.) The organic electroluminescent element according to claim 1, wherein the structure represented by the general formula (1) is represented by the following general formula (3).

(Wherein, R ³ represents an alkyl group, an aryl group, a heteroaryl group, or a halogen atom,, p1 is .p1 amino R ³ represents an integer of 2 to 5 may be the same as or different from each other, p1 pieces At least two of R ^{3 in} the formula are fluorine atoms.) The organic electroluminescent element according to claim 1, wherein the compound containing the structure represented by the general formula (1) as a partial structure is represented by the following general formula (4).

(In the formula, R ⁴¹ and R ⁴² represent an alkyl group, an aryl group, a heteroaryl group, or a halogen atom, and q 1 and q 2 each independently represent an integer of 2 to 5, but q 1 R ⁴¹ At least two, and at least two of q2 R ⁴² are fluorine atoms, R ⁴³ and R ^{44 each} represents an alkyl group, an aryl group, a heteroaryl group, or a halogen atom, and q3 and q4 are independent of each other. Represents an integer of 0 to 8.) The organic electroluminescence device according to claim 1, wherein the compound containing the structure represented by the general formula (1) as a partial structure is represented by the following general formula (5).

^{(Wherein, R 51,} and ^{R 52} is an alkyl group, an aryl group, a heteroaryl group, or a halogen atom,, r1, and r2 in independently of one another represent an integer of from 2 to 5, r1 amino ^{R 51} At least two and at least two of the r2 R ⁵² are fluorine atoms, R ⁵³ represents an alkyl group, an aryl group, a heteroaryl group, or a halogen atom, and r3 represents an integer of 0 to 10. r3 represents If 2 or more, r3 one R ⁵³ may be the same or different from each other.)