JP5574563B2 - Fluorene compound, organic electroluminescence device and display device using the same - Google Patents

Description

  The present invention relates to a novel fluorene compound, an organic electroluminescent element using the same, and a display device.

  An organic electroluminescent element is an element in which a thin film containing a fluorescent organic compound or a phosphorescent organic compound is sandwiched between an anode and a cathode. By injecting electrons and holes from each electrode, excitons of a fluorescent organic compound or a phosphorescent organic compound are generated, and when this returns to the ground state, the organic electroluminescent device emits light.

  Many studies have been made on organic electroluminescent devices. Recently, organic electroluminescent devices using an oligofluorene compound disclosed in Patent Document 1 as a luminescent material have been proposed. Since Patent Document 1 describes that a light-emitting device using the oligofluorene compound has high efficiency, unlike a polymer, the usefulness of an oligofluorene compound having a single molecular weight is being recognized. However, there is no practical level of oligofluorene compound having both high efficiency and high durability, and a host material or a light-emitting material that can be expected to have higher luminance and longer life has been desired.

Further, known oligofluorene compound is a fluorene 2-position adjacent the 2-position is a structure linked by a single bond, triplet excitation energy level (hereinafter, referred to as T ₁ .T ₁ is a phosphorescent spectrum The energy level calculated from the light emitting end on the short wavelength side) is a small value. Therefore, the oligofluorene compound could not be used for applications where a high triplet excitation energy level is essential, such as a host of a green phosphorescent light emitting device.

U.S. Pat. No. 7,057,009

  An object of the present invention is to provide a novel fluorene compound. Another object of the present invention is to provide an organic electroluminescent device having both high efficiency and high durability. Furthermore, another object of the present invention is to provide an organic electroluminescent device that is easy to manufacture and can be produced by a relatively inexpensive coating method.

  The fluorene compound of the present invention is represented by the following general formula [I].

（＊は、結合手を表す。）
を表す。
Ｒ₁₄は、Ｒ₁₆乃至Ｒ₁₈及びＲ₂₂乃至Ｒ₂₄のいずれか１つと連結する結合手、水素原子又は下記に示される置換基

（＊は、結合手を表す。）
を表す。
Ｒ₁₅は、Ｒ₁₆乃至Ｒ₁₈及びＲ₂₂乃至Ｒ₂₄のいずれか１つと連結する結合手、水素原子又は下記に示される置換基

（＊は、結合手を表す。）
を表す。
尚、Ｒ₁₃乃至Ｒ₁₅のうちいずれか１つが結合手である。
Ｒ₁₆は、Ｒ₇乃至Ｒ₉及びＲ₁₃乃至Ｒ₁₅のいずれか１つと連結する結合手、水素原子又は下記に示される置換基

（＊は、結合手を表す。）
を表す。
Ｒ₁₇は、Ｒ₇乃至Ｒ₉及びＲ₁₃乃至Ｒ₁₅のいずれか１つと連結する結合手、水素原子又は下記に示される置換基

（＊は、結合手を表す。）
を表す。
Ｒ₁₈は、Ｒ ₈ 、Ｒ ₉ 、Ｒ ₁₄ 及びＲ₁₅のいずれか１つと連結する結合手、水素原子又は下記に示される置換基

（＊は、結合手を表す。）
を表す。
尚、Ｒ₁₆乃至Ｒ₁₈のうちいずれか１つが結合手である。
Ｒ₂₂は、Ｒ₁₃乃至Ｒ₁₅のいずれか１つと連結する結合手、水素原子又はアルキル基を表す。ただし、Ｒ₂₃が結合手である場合、Ｒ₂₂は、水素原子を表す。
Ｒ₂₃は、Ｒ₁₃乃至Ｒ₁₅のいずれか１つと連結する結合手、水素原子又はアルキル基を表す。ただし、Ｒ₂₄又はＲ₂₂が結合手である場合、Ｒ₂₃は、水素原子を表す。
Ｒ₂₄は、Ｒ₁₄あるいはＲ₁₅と連結する結合手、水素原子又はアルキル基を表す。ただし、Ｒ₂₃が結合手である場合、Ｒ₂₄は、水素原子を表す。
尚、Ｒ₂₂乃至Ｒ₂₄のうちいずれか１つが結合手である。
Ｒ₁₀乃至Ｒ₁₂及びＲ₁₉乃至Ｒ₂₁は、それぞれ水素原子又はアルキル基を表す。） (In the formula [I], n represents an integer of 1 to 20.)
R _{1 to} R ₆ each represents an alkyl group.
R ₇ represents a bond, a hydrogen atom or an alkyl group linking the R ₁₆ or R _17. However, when R ₈ is a bond, R ₇ represents a hydrogen atom.
R ₈ represents any one connected to bond, hydrogen atom or an alkyl group of R ₁₆ to R _18. However, when R ₇ or R ₉ is a bond, R ₈ represents a hydrogen atom.
R ₉ represents any one connected to bond, hydrogen atom or an alkyl group of R ₁₆ to R _18. However, when R ₈ is a bond, R ₉ represents a hydrogen atom.
Any one of R _{7 to} R ₉ is a bond.
R ₁₃ is a bond connected to R ₁₆ , R ₁₇ , R ₂₂ or R ₂₃ , a hydrogen atom, or a substituent shown below.

(* Represents a bond.)
Represents.
R ₁₄ represents a bond, a hydrogen atom or a substituent shown below that is linked to any one of R _{16 to} R ₁₈ and R _{22 to} R _24.

(* Represents a bond.)
Represents.
R ₁₅ represents a bond, a hydrogen atom, or a substituent shown below that is linked to any one of R _{16 to} R ₁₈ and R _{22 to} R _24.

(* Represents a bond.)
Represents.
One of R _{13 to} R ₁₅ is a bond.
R ₁₆ represents a bond, a hydrogen atom, or a substituent shown below that is linked to any one of R _{7 to} R ₉ and R _{13 to} R _15.

(* Represents a bond.)
Represents.
R ₁₇ represents a bond, a hydrogen atom, or a substituent shown below , linked to any one of R _{7 to} R ₉ and R _{13 to} R _15.

(* Represents a bond.)
Represents.
R ₁₈ represents a bond, a hydrogen atom, or a substituent shown below , linked to any one of R ₈ , R ₉ , R ₁₄ and R _15.

(* Represents a bond.)
Represents.
Any one of R _{16 to} R ₁₈ is a bond.
R ₂₂ represents a bond, a hydrogen atom or an alkyl group of any one connection of R ₁₃ to R _15. However, when R ₂₃ is a bond, R ₂₂ represents a hydrogen atom.
R ₂₃ represents a bond, a hydrogen atom or an alkyl group of any one connection of R ₁₃ to R _15. However, when R ₂₄ or R ₂₂ is a bond, R ₂₃ represents a hydrogen atom.
R ₂₄ represents a bond, a hydrogen atom or an alkyl group linking the R ₁₄ or R _15. However, if R ₂₃ is a bond, R ₂₄ represents a hydrogen atom.
One of R _{22 to} R ₂₄ is a bond.
R _{10 to} R ₁₂ and R _{19 to} R ₂₁ each represent a hydrogen atom or an alkyl group . )

  According to the present invention, a novel fluorene compound can be provided. In particular, the fluorene compound of the present invention is excellent as a host constituting the light emitting material and the light emitting layer. Moreover, according to this invention, the organic electroluminescent element which combines high efficiency and high durability can be provided.

  Hereinafter, the present invention will be described in detail.

  First, the fluorene compound of the present invention will be described. The fluorene compound of the present invention is represented by the following general formula [I].

In the formula [I], adjacent fluorene rings are connected by a single bond having any of the following combinations of substituents as a bond.
(1) Substituent at position 2 and substituent at position 3 (2) Substituent at position 2 and substituent at position 4 (3) Substituent at position 3 and substituent at position 3 (4) Substituent at position 3 And 4-position substituent (5) 4-position substituent and 4-position substituent

That is, R _{7 to} R ₉ , R _{13 to} R ₁₈ and R _{22 to} R ₂₄ of the fluorene compound of the formula [I] can be a bond for connecting adjacent fluorene rings. A specific combination of substituents serving as bonds will be described later.

  In the formula [I], n represents an integer of 1 to 20. When n is 0, the fluorene compound of the formula [I] is a dimer having two fluorene rings. However, since this dimer has a low molecular weight, its melting point, crystallization temperature or glass transition temperature is low, and when a thin film is formed, the thin film may be thermally unstable. When n is larger than 20, synthesis and purification become difficult, and it may be difficult to obtain a material with high purity.

  In the case where n is 1, combinations of substituents that can serve as bonds for connecting adjacent fluorene rings are shown in the following table.

  When n is 1, two single bonds for connecting adjacent fluorene rings are formed. At this time, the first single bond is formed with a combination of one set of substituents selected from the first group as a bond. The second single bond is formed with a combination of one set of substituents selected from the second group as a bond.

  When n is 2 or more, combinations of substituents that can be a bond for connecting adjacent fluorene rings are shown in the following table.

  When n is 2 or more, n + 1 single bonds for connecting adjacent fluorene rings are formed. At this time, the first single bond is formed with a combination of one set of substituents selected from the first group as a bond. The second to n-th single bonds are each formed using a combination of one set of substituents selected from the second group as a bond. Furthermore, the (n + 1) th single bond is formed using a combination of one substituent selected from the third group as a bond.

  n is preferably an integer of 2 to 15.

In the formula [I], R _{1 to} R ₆ each represents a substituent selected from an alkyl group, a fluorinated alkyl group, a substituted or unsubstituted aralkyl group, and a substituted or unsubstituted aryl group.

Examples of the alkyl group represented by R _{1 to} R ₆ include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, secondary butyl group, tertiary butyl group, pentyl group, isopentyl group, hexyl. Group, cyclopropyl group, cyclopentyl group, cyclohexyl group and the like.

Examples of the fluorinated alkyl group represented by R _{1 to} R ₆ include a trifluoromethyl group and a pentafluoroethyl group.

Examples of the aralkyl group represented by R _{1 to} R ₆ include a benzyl group, a phenethyl group, a naphthylmethyl group, and a naphthylethyl group.

Examples of the aryl group represented by R _{1 to} R ₆ include a phenyl group, a biphenyl group, and a terphenyl group.

  As the substituents that the aralkyl group and aryl group may have, alkyl groups such as methyl group, ethyl group and n-propyl group, fluorinated alkyl groups such as trifluoromethyl group and pentafluoroethyl group, benzyl group, Aralkyl groups such as phenethyl group, aryl groups such as phenyl group, biphenyl group, terphenyl group, thienyl group, pyrrolyl group, pyridyl group, bipyridyl group, heterocyclic groups such as oxazolyl group, oxadiazolyl group, thiazolyl group, thiadiazolyl group, Condensed polycyclic aromatic groups such as naphthyl group and phenanthryl group, condensed polycyclic heterocyclic groups such as quinolyl group, carbazolyl group, acridinyl group and phenanthryl group, aryloxy groups such as phenoxyl group and naphthoxyl group, dimethylamino group, Diethylamino group, diphenylamino group, ditolylamino group, di Nisolylamino group, fluorenylphenylamino group, difluorenylamino group, substituted amino group such as naphthylphenylamino group, dinaphthylamino group, substituted boryl group such as diphenylboryl group, dimesitylboryl group, trimethylsilyl group, triphenylsilyl group And substituted silyl groups such as trimethylgermyl group and triphenylgermyl group, halogen atoms such as fluorine, chlorine, bromine and iodine, and deuterium.

In the formula [I], a substituent that is not a bond among R _{7 to} R ₂₄ represents an alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted condensed polycyclic aromatic group, or an arylamino group, respectively. .

Examples of the alkyl group represented by R _{7 to} R ₂₄ include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, secondary butyl, tertiary butyl, pentyl, hexyl, cyclo A propyl group, a cyclopentyl group, a cyclohexyl group, etc. are mentioned.

Examples of the aryl group represented by R _{7 to} R ₂₄ include a phenyl group, a biphenyl group, and a terphenyl group.

Examples of the condensed polycyclic aromatic group represented by R _{7 to} R ₂₄ include a naphthyl group, a phenanthryl group, a tolyl group, a xylyl group, a methylnaphthyl group, an anthryl group, a fluorenyl group, and a bifluorenyl group.

Examples of the arylamino group represented by R _{7 to} R ₂₄ include a diphenylamino group, a ditolylamino group, a dianisolylamino group, a fluorenylphenylamino group, a difluorenylamino group, a naphthylphenylamino group, a dinaphthylamino group, and the like. Is mentioned.

  Examples of the substituent that the aryl group and the condensed polycyclic aromatic group may have include an alkyl group such as a methyl group, an ethyl group, an n-propyl group, a tertiary butyl group, and an isopentyl group, a trifluoromethyl group, and a penta group. Fluorinated alkyl groups such as fluoroethyl group, aralkyl groups such as benzyl group and phenethyl group, aryl groups such as phenyl group, biphenyl group and terphenyl group, thienyl group, pyrrolyl group, pyrrolyl group, pyridyl group, bipyridyl group, oxazolyl group, oxadiazolyl Group, heterocyclic ring such as thiazolyl group, thiadiazolyl group, condensed polycyclic aromatic group such as naphthyl group, phenanthryl group, condensed polycyclic heterocyclic group such as quinolyl group, carbazolyl group, acridinyl group, phenanthryl group, phenoxyl group Aryloxy group such as naphthoxyl group, dimethylamino group, diethylamino group, diphth Substituted amino groups such as nylamino group, ditolylamino group, dianisolylamino group, fluorenylphenylamino group, difluorenylamino group, naphthylphenylamino group, dinaphthylamino group, etc., substituted boryl such as diphenylboryl group, dimesitylboryl group, etc. Groups, substituted silyl groups such as trimethylsilyl group and triphenylsilyl group, substituted germyl groups such as trimethylgermyl group and triphenylgermyl group, halogen atoms such as fluorine, chlorine, bromine and iodine, deuterium and the like.

Of R _{7 to} R ₂₄ , adjacent substituents may be bonded to form a ring structure. Specific examples of the ring structure include a cyclopentene ring, a cyclopentadiene ring, an acenaphthylene ring, a condensed ring containing a 5-membered ring such as an acanthrene ring, a cyclohexadiene ring, a cyclohexene ring, a benzene ring, a naphthalene ring, and a phenanthrene. Ring, fluorene ring, fluoranthene ring, triphenylene ring, chrysene ring, condensed ring containing 6-membered ring such as phenalene ring, seven-membered ring such as cycloheptene ring, eight-membered ring such as cyclooctene ring, etc. .

  The fluorene compound of the present invention can be obtained by a generally known synthesis method. For example, the Suzuki Coupling method using a palladium catalyst (for example, Chem. Rev., 95, 2457, 1995) can be used. Further, the Yamamoto method using a nickel catalyst (for example, Bull. Chem. Soc. Jpn. 51, 2091, 1978) can be used.

  The fluorene compound of the present invention has the following characteristics.

  (A) Since the deposited film exhibits a high amorphous property, a fluorene compound that does not cause whitening (crystallization, aggregation, etc.) of the film even when stored for a long period of time or heated is obtained.

  (B) Since it exhibits excellent solubility in various solvents, a fluorene compound having high adaptability to a coating method (Wet process) can be obtained.

  (C) Since the fluorene ring itself is bipolar, a fluorene compound having a high carrier transport capacity for both holes and electrons can be obtained.

(D) Compared with the case where the fluorene ring is connected at the 2-position and the 2-position, the conjugated length does not extend even when the fluorene ring is connected, so that a fluorene compound having a high triplet excitation energy (T ₁ ) can be obtained. In particular, a fluorene compound having T ₁ (2.5 eV or more) higher than T _{1 of} the green phosphorescent material is preferable.

  Next, representative examples of the fluorene compound of the present invention are shown below, but the present invention is not limited to these.

  Next, the organic electroluminescent element of the present invention will be described in detail.

  The organic electroluminescent element of the present invention comprises an anode, a cathode, and a layer made of an organic compound sandwiched between the anode and the cathode.

  Hereinafter, the organic electroluminescent element of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an example of an embodiment of the organic electroluminescent device of the present invention, where (a) shows the first embodiment, (b) shows the second embodiment, and (c) shows the first embodiment. Three embodiments are shown.

  The organic electroluminescent device 1 in FIG. 1A has a laminate in which a metal electrode 10, an electron injection / transport layer 11, a light emitting layer 12, a hole injection / transport layer 13, and a transparent electrode 14 are stacked in this order. It is provided on the transparent substrate 15.

  In the organic electroluminescent device 1 of FIG. 1A, the obtained device exhibits electrical rectification. When an electric field is applied so that the metal electrode 10 serves as a cathode and the transparent electrode 14 serves as an anode, electrons are injected from the metal electrode 11 and holes are injected from the transparent electrode 14 into the light emitting layer 12. The injected holes and electrons recombine in the light emitting layer 12 to generate excitons of the light emitting material, and the organic electroluminescence device 1 emits light when the excitons return to the ground state. At this time, since the hole injection / transport layer 13 also serves as an electron blocking layer, the recombination efficiency of holes and electrons at the interface between the light emitting layer 12 and the hole injection / transport layer 13 is increased. Luminous efficiency is improved.

  In the organic electroluminescent element 2 of FIG. 1B, an interlayer 16 is provided between the light emitting layer 12 and the hole injection / transport layer 13 in the organic electroluminescent element 1 of FIG. By providing the interlayer layer 16, electrons can be blocked more effectively, and the diffusion ions oozing out from the transparent electrode 14 and the hole injection / transport layer 13 can be blocked. Thereby, the luminous efficiency of the element is improved and the durability is also improved.

  In the organic electroluminescent element 3 in FIG. 1C, a laminate in which the metal electrode 11, the multifunctional light emitting layer 17, and the transparent electrode 14 are laminated in this order from the top is provided on the transparent substrate 15. The organic electroluminescent element of the present invention may have only one layer made of an organic compound sandwiched between electrodes, as shown in the organic electroluminescent element 3 in FIG. However, in this embodiment, the host or guest constituting the multifunctional light emitting layer 17 must be a multifunctional material having either high carrier injection ability or high carrier transport ability. Therefore, in the case of the element configuration shown in the organic electroluminescent element 3 of FIG. 1C, the multifunctional light emitting layer 17 is preferably a layer formed by mixing the fluorene compound of the present invention and another organic compound. is there.

  However, FIGS. 1A to 1C are just basic device configurations, and the configuration of the organic electroluminescent device of the present invention is not limited to these. For example, an insulating layer is provided at the interface between the electrode and the organic layer, an adhesive layer or an interference layer is provided, and the hole injection / transport layer or the electron injection / transport layer is composed of two layers having different ionization potentials or energy band gaps. A simple layer structure can be taken.

  The organic electroluminescent element of the present invention is characterized in that at least one kind of the fluorene compound of the present invention is contained in a layer made of an organic compound. Here, the layer made of an organic compound specifically refers to the electron injection / transport layer 11, the light emitting layer 12, the hole injection / transport layer, the interlayer layer 16, and the multiple layers shown in FIGS. This refers to the functional light emitting layer 17. The light emitting layer 12 or the multifunctional light emitting layer 17 is preferable.

  By the way, although the light emitting layer 12 and the multifunctional light emitting layer 17 may be comprised only with the fluorene compound of this invention, Preferably, it is comprised from a host and a guest. When the light emitting layer 12 and the multifunctional light emitting layer 17 are comprised from a host and a guest, the fluorene compound of this invention is used as a host. A guest included in the light emitting layer 12 or the multifunctional light emitting layer 17 together with the host is a fluorescent light emitting material or a phosphorescent light emitting material.

  As the fluorescent light-emitting material or phosphorescent light-emitting material that is a guest, specifically, 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 derivatives thereof, pyrrolopyridine and derivatives thereof, thiadiazolopyridine and derivatives thereof Derivatives, cyclopentadiene and derivatives thereof, 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, rare earth complexes, transition metals Examples include various metal complexes represented by complexes, polymer compounds such as polythiophene, polyphenylene, and polyphenylene vinylene, organic silanes, and derivatives thereof. 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.

  The organic electroluminescent element of the present invention preferably uses phosphorescence from a phosphorescent material from the viewpoint of efficiency (external quantum efficiency).

  The phosphorescent light emitting material is preferably a transition metal complex. When the transition metal complex is used as a phosphorescent light emitting material, the central metal of the complex is not particularly limited, but is preferably iridium, platinum, rhenium, or ruthenium, more preferably iridium or platinum, and particularly preferably. Iridium. Here, as the transition metal complex, specifically, ortho-metalated complexes disclosed in the documents listed below can be used.

1. Akio Yamamoto, “Organic Metals Fundamentals and Applications”, p. 150 and p. 232, Shukubosha (1982)
2. H. Yersin, “Photochemistry and Photophysics and Photophysics of Coordination Compound”, pages 71-77 and pages 135-146, Spring. (1987)
3. (Japan) Japan Society for the Promotion of Science "Organic Materials for Information Science, 142nd Committee", Group C (Organic Electroics), 9th meeting, materials 25-32 (2005)

  In addition to the above, those disclosed in patent documents such as US Pat. No. 6,303,231, US Pat. No. 6,097,147, WO00 / 57676, WO00 / 70655, WO01 / 08230, WO01 / 39234 pamphlet, WO01 / 41512 pamphlet, WO02 / 02714 pamphlet, WO02 / 15645 pamphlet, Japanese Patent Application No. 2001-247859, Japanese Patent Application No. 2000-33561, Japanese Patent Application No. 2001-189539, and Japanese Patent Application No. 2001-248165. No., Japanese Patent Application No. 2001-33684, Japanese Patent Application No. 2001-239281, Japanese Patent Application No. 2001-219909, European Patent No. 1211,257, Japanese Patent Application Laid-Open No. 2002-226495, Japanese Patent Application Laid-Open No. 2002-234. No. 94, JP-A No. 2001-247859, JP-A No. 2001-298470, JP-A No. 2002-173684, JP-A No. 2002-203678, JP-A No. 2002-203679, and the like. A phosphorescent light emitting material can be preferably used.

  Also disclosed in non-patent literature, for example, Nature, 395, 151 (1998), Applied Physics Letters, 75, 4 (1999). Polymer Preprints, 41, 770 (2000), Journal of American Chemical Society, 123, 4304 (2001), Applied Physics. Phosphorescent light-emitting materials described in Letters (Applied Physics Letters), vol. 79, p. 2082 (1999) can also be used suitably.

  Furthermore, in addition to the fluorene compound of the present invention and the fluorescent or phosphorescent light emitting material, it is more preferable that the third organic compound is contained in the light emitting layer 12 or the multifunctional light emitting layer 17.

  Examples of the third organic compound include known charge transport materials. Specifically, it can be appropriately selected from the constituent material of the hole injection / transport layer 13 and the constituent material of the electron injection / transport layer 11 described later. The content of the third organic compound is preferably 1% by weight or more and 50% by weight or less, more preferably 5% by weight, based on the total weight of the constituent materials of the light emitting layer 12 or the multifunctional light emitting layer 17. Above 30% by weight. When it is less than 1% by weight, the effect of the added organic compound is not exhibited. That is, if a hole transporting compound is used, a desired hole transporting ability cannot be obtained, and if it is an electron transporting compound, a desired electron transporting ability cannot be obtained. On the other hand, when it is larger than 50% by weight, the characteristics of the added organic compound are superior, and the characteristics (film stability, high efficiency, high durability, etc.) of the fluorene compound of the present invention may be greatly affected.

  Next, other constituent members constituting the organic electroluminescent element of the present invention will be described.

  The constituent material of the interlayer layer 16 is not particularly limited as long as it is a wide gap, has a charge transport ability, and is excellent in film quality stability (electrical, chemical or thermal stability). For example, PVK (polyvinyl carbazole) etc. are mentioned.

  The constituent material of the hole injection / transport layer 13 is not particularly limited, but can be selected from hole transport materials that can be used as the third organic compound in the organic electroluminescence device of the present invention. Specifically, triarylamine derivatives, phenylenediamine derivatives, triazole derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives, pyrazolone derivatives, oxazole derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, phthalocyanine derivatives, porphyrin derivatives, poly (Vinyl carbazole), poly (silylene), poly (thiophene) and the like.

  The constituent material of the electron injecting / transporting layer 11 is not particularly limited, and can be selected from electron transporting materials that can be used as the third organic compound in the organic electroluminescence device of the present invention. Specifically, oxadiazole derivatives, oxazole derivatives, thiazole derivatives, thiadiazole derivatives, pyrazine derivatives, triazole derivatives, triazine derivatives, perylene derivatives, quinoline derivatives, quinoxaline derivatives, fluorenone derivatives, anthrone derivatives, phenanthroline derivatives, quinolinol aluminum complexes, etc. And organic compounds such as organometallic complexes. Other metals such as lithium, sodium, potassium, cesium, calcium, magnesium, aluminum, indium, silver, lead, tin, chromium, metal fluorides such as lithium fluoride, or metal carbonates such as cesium carbonate You may use individually and may be used in mixture with the said organic compound.

  The constituent material of the anode should have a work function as large as possible. For example, a metal simple substance such as gold, silver, platinum, nickel, palladium, cobalt, selenium, vanadium, or a combination thereof, a metal oxide such as tin oxide, zinc oxide, indium tin oxide (ITO), indium zinc oxide, etc. Can be used. In addition, conductive polymers such as polyaniline, polypyrrole, polythiophene, and polyphenylene sulfide can also be used. These electrode materials may be used alone or in combination of two or more. Moreover, the anode may be composed of a single layer or a plurality of layers.

  On the other hand, the constituent material of the cathode is preferably a material having a small work function. For example, a single metal such as lithium, sodium, potassium, cesium, calcium, magnesium, aluminum, indium, silver, lead, tin, chromium, an alloy in which a plurality of these metals are combined, or a salt thereof can be used. A metal oxide such as indium tin oxide (ITO) can also be used. Moreover, the cathode may be composed of a single layer or a plurality of layers.

  The substrate used in the organic electroluminescence device of the present invention is not particularly limited, but an opaque substrate such as a metal substrate or a ceramic substrate, or a transparent substrate such as glass, quartz, or a plastic sheet is used. . It is also possible to control the color light by using a color filter film, a fluorescent color conversion filter film, a dielectric reflection film or the like on the substrate.

The organic electroluminescent element of the present invention is preferably finally covered with a protective layer. As a material for the protective layer, any material may be used as long as it has a function of preventing materials 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 , nitrides such as SiN _x and SiO _x N _y , polyethylene, polypropylene, polymethyl methacrylate Polyimide, polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, a copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, and a monomer mixture containing tetrafluoroethylene and at least one comonomer. A copolymer obtained by polymerization and a fluorine-containing copolymer having a cyclic structure in the copolymer main chain; Coalescence, 1% by weight of the water absorbing water absorption material, water absorption of 0.1% or less of moisture-proof material, and the like.

  In the organic electroluminescence device of the present invention, each layer constituting the device including the layer containing the fluorene compound of the present invention is generally formed into a thin film by a vacuum deposition method or a solution coating method. Specific examples of the solution coating method include a spin coating method, a slit coater method, a printing method, an ink jet method, and a spray method.

  A specific method of forming the hole injection / transport layer 13 and the light emitting layer 12 by a coating method (Wet process) in the organic electroluminescent device of FIG. First, a hole injection / transport layer 13 (PEDOT / PSS film) is formed by dropping a solution made of polyethylene dioxythiophene / polystyrene sulfonate (PEDOT / PSS) or the like onto the ITO substrate to form a film. Form. Next, a coating ink comprising the fluorene compound of the present invention, a fluorescent or phosphorescent light emitting material, and a solvent (possibly a third organic compound) is dropped onto the PEDOT / PSS film to form a film. Thus, the light emitting layer 12 is formed.

  Thus, the layer containing the fluorene compound of the present invention can be formed between the anode and the cathode by a vacuum deposition method or a solution coating method. Here, among the fluorene compounds of the present invention, a compound having a molecular weight exceeding 2000 tends to increase the sublimation temperature of the compound itself, so that the solution coating method is preferred.

  In particular, when a film is formed by a coating method, the film can be formed in combination with an appropriate binder resin.

  The binder resin can be selected from a wide range of binder resins. For example, polyvinyl carbazole resin, polycarbonate resin, polyester resin, polyarylate resin, polystyrene resin, acrylic resin, methacrylic resin, butyral resin, polyvinyl acetal resin, diallyl phthalate resin, phenol resin, epoxy resin, silicone resin, polysulfone resin, urea resin, etc. However, it is not limited to these. These binder resins may be homopolymers or copolymer polymers. Furthermore, these binder resins may be used alone or in combination of two or more.

  There is no particular limitation on the method for forming the protective layer. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy (MBE), 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 film thickness of the layer containing the fluorene compound of the present invention is less than 10 μm, preferably 0.5 μm or less, and more preferably 0.01 μm or more and 0.5 μm or less.

  Next, the ink composition of the present invention will be described.

  The ink composition of the present invention contains at least one fluorene compound of the present invention. By using the ink composition of the present invention, it is possible to produce a layer made of an organic compound constituting an organic electroluminescent element, in particular, the light emitting layer 12 or the multifunctional light emitting layer 17 by a coating method, which is relatively inexpensive. Large-area devices can be easily manufactured. In particular, a fluorene compound having a molecular weight of 2000 or more tends to increase the sublimation temperature of the compound, and is therefore preferably used as an ink composition by dissolving in a suitable solvent.

  Examples of the solvent used in the ink composition of the present invention include toluene, xylene, mesitylene, dioxane, tetralin, methylnaphthalene, tetrahydrofuran, diglyme and the like.

  In the ink composition of the present invention, the content of the solute composed of the fluorene compound of the present invention is preferably 0.05% by weight or more and 20% by weight or less, more preferably, relative to the entire ink composition. It is 0.1 wt% or more and 10 wt% or less. When the content of the solute is less than 0.05% by weight, the concentration of the solute (solid content in the ink) becomes extremely small, and the film quality stability may be impaired when the film is formed. Further, when the content of the solute is larger than 20% by weight, there is a concern that the solute is precipitated from the ink or the film becomes thick when the film is formed.

  The organic electroluminescence device of the present invention can be applied to products that require energy saving and high luminance. Application examples include a display device, a light source of a printer, an illumination device, a backlight of a liquid crystal display device, and the like.

  Examples of the display device include a flat panel display that is energy-saving, highly visible, and lightweight.

  Moreover, as a light source of a printer, the laser light source part of the laser beam printer currently widely used can be replaced with the organic electroluminescent element of the present invention, for example. As a replacement method, for example, a method of arranging an organic electroluminescent element that can be independently addressed on the array can be mentioned. Even when the laser light source portion is replaced with the organic electroluminescent element of the present invention, image formation is not different from conventional methods by performing desired exposure on the photosensitive drum. Here, by using the organic electroluminescent element of the present invention, the volume of the apparatus can be greatly reduced.

  With respect to the illumination device and the backlight, an energy saving effect can be expected by using the organic electroluminescent element of the present invention.

  Next, a display device using the organic electroluminescent element of the present invention will be described. Hereinafter, the display device of the present invention will be described in detail with reference to the drawings, taking an active matrix system as an example.

  FIG. 2 is a diagram schematically illustrating a configuration example of a display device including the organic electroluminescence element of the present invention and a driving unit, which is an embodiment of the display device. 2 includes a scanning signal driver 21, an information signal driver 22, and a current supply source 23, which are connected to a gate selection line G, an information signal line I, and a current supply line C, respectively. A pixel circuit 24 is disposed at the intersection of the gate selection line G and the information signal line I. The scanning signal driver 21 sequentially selects the gate selection lines G1, G2, G3... Gn, and in synchronization therewith, any one of the information signal lines I1, I2, I3. The voltage is applied to the pixel circuit 24 via these.

Next, the operation of the pixel will be described. FIG. 3 is a circuit diagram showing a circuit constituting one pixel arranged in the display device of FIG. In the pixel circuit 30 of FIG. 3, when a selection signal is applied to the gate selection line Gi, the first thin film transistor (TFT1) 31 is turned on, the image signal Ii is supplied to the capacitor (C _add ) 32, The gate voltage of the second thin film transistor (TFT2) 33 is determined. A current is supplied to the organic electroluminescent element 34 from the current supply line Ci according to the gate voltage of the second thin film transistor (TFT2) (33). Here, the gate potential of the second thin film transistor (TFT2) 33 is held in the capacitor ( _Cadd ) 32 until the first thin film transistor (TFT1) 31 is next selected for scanning. Therefore, current continues to flow through the organic electroluminescent element 34 until the next scanning is performed. As a result, the organic electroluminescent element 34 can always emit light during one frame period.

  FIG. 4 is a schematic diagram showing an example of a cross-sectional structure of a TFT substrate used in the display device of FIG. Details of the structure will be described below while showing an example of the manufacturing process of the TFT substrate. When the display device 40 of FIG. 4 is manufactured, a moisture-proof film 42 for protecting a member (TFT or organic layer) formed on the top is first coated on a substrate 41 such as glass. As a material constituting the moisture-proof film 42, silicon oxide or a composite of silicon oxide and silicon nitride is used. Next, a gate electrode 43 is formed by patterning into a predetermined circuit shape by depositing a metal such as Cr by sputtering. Subsequently, silicon oxide or the like is formed by plasma CVD or catalytic chemical vapor deposition (cat-CVD) or the like, and patterned to form the gate insulating film 44. Next, a silicon film is formed by a plasma CVD method or the like (in some cases, annealed at a temperature of 290 ° C. or higher), and a semiconductor layer 45 is formed by patterning according to a circuit shape.

  Further, a drain electrode 46 and a source electrode 47 are provided on the semiconductor film 45 to produce a TFT element 48, thereby forming a circuit as shown in FIG. Next, an insulating film 49 is formed on the TFT element 48. Next, a contact hole (through hole) 50 is formed so that the anode 51 for the organic electroluminescence element made of metal and the source electrode 47 are connected.

  The display device 40 can be obtained by sequentially laminating a multilayer or single layer organic layer 52 and a cathode 53 on the anode 51. At this time, a first protective layer 54 and a second protective layer 55 may be provided in order to prevent deterioration of the organic electroluminescent element. By driving the display device using the fluorene compound of the present invention, stable display can be achieved with good image quality and long-time display.

  Note that the display device is not particularly limited to a switching element, and can be easily applied to a single crystal silicon substrate, an MIM element, an a-Si type, or the like.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

  Example 1 <Exemplary Compound No. Synthesis of 14>

  The following reagents and solvents were charged into a 200 ml three-necked flask.

Compound A-1: 0.5 g (0.58 mmol)
Pinacol borane compound (Compound A-2): 0.55 g (1.27 mmol)
Toluene: 40ml
Ethanol: 10ml

  Next, while stirring the reaction solution at room temperature under a nitrogen atmosphere, 10 ml of a saturated aqueous sodium carbonate solution was added, and then 0.13 g (0.12 mmol) of tetrakis (triphenylphosphine) palladium (0) was added. Next, the reaction solution was stirred at room temperature for 30 minutes, and then stirred for 18 hours while refluxing the reaction solution. After completion of the reaction, the organic layer was extracted with chloroform and dried, and then the solvent was distilled off under reduced pressure to obtain a crude product. Next, this crude product was purified by silica gel column chromatography (developing solvent: hexane-chloroform mixed solvent), whereby Exemplified Compound No. 14 (compound A-3) was obtained as a white solid (0.25 g, yield 35.2%).

The obtained Exemplified Compound No. For 14, Journal of the American Chemical Society , was calculated for T ₁ in compliance with the method described in 125,15310 (2003). First, this Exemplified Compound No. 14 was dissolved in toluene to prepare a toluene solution of 10 ⁻⁴ mol / l to 10 ⁻³ mol / l. About this toluene solution, the phosphorescence spectrum in 77K was measured using the spectrofluorimeter F-4500 (made by Hitachi High-Technologies). After obtaining the wavelength λ of the light emitting end on the short wavelength side of the phosphorescence spectrum obtained by this measurement, T ₁ (eV) was calculated by the following equation.

T ₁ (eV) = 1240 / λ

  The results are shown in Table 3.

  Example 2 <Exemplary Compound No. Synthesis of 17>

  The following reagents and solvents were charged into a 200 ml three-necked flask.

Compound B-1: 0.5 g (0.78 mmol)
Pinacol borane compound (Compound B-2): 1.18 g (2.73 mmol)
Toluene: 40ml
Ethanol: 10ml

  Next, while stirring the reaction solution at room temperature under a nitrogen atmosphere, 10 ml of a saturated aqueous sodium carbonate solution was added, and then 0.18 g (0.16 mmol) of tetrakis (triphenylphosphine) palladium (0) was added. Next, the reaction solution was stirred at room temperature for 30 minutes, and then stirred for 18 hours while the reaction solution was refluxed. After completion of the reaction, the organic layer was extracted with chloroform and dried, and then the solvent was distilled off under reduced pressure to obtain a crude product. Next, this crude product was purified by silica gel column chromatography (developing solvent: hexane-chloroform mixed solvent), whereby Exemplified Compound No. Obtained 0.22 g (yield 23.2%) of 17 (Compound B-3) as a white solid.

The obtained Exemplified Compound No. For 17, the phosphorescence spectrum was measured in the same manner as in Example 1, was calculated T ₁ from the obtained phosphorescence spectrum. The results are shown in Table 3.

  Example 3 <Exemplary Compound No. Synthesis of 18>

  The following reagents and solvents were charged into a 200 ml three-necked flask.

Compound C-1: 0.5 g (0.70 mmol)
Pinacol borane compound (Compound C-2): 1.36 g (3.15 mmol)
Toluene: 80ml
Ethanol: 20ml

  Next, 20 ml of a saturated aqueous sodium carbonate solution was added while stirring the reaction solution at room temperature under a nitrogen atmosphere, and then 0.24 g (0.21 mmol) of tetrakis (triphenylphosphine) palladium (0) was added. Next, the reaction solution was stirred at room temperature for 30 minutes, and then stirred for 18 hours while refluxing the reaction solution. After completion of the reaction, the organic layer was extracted with chloroform and dried, and then the solvent was distilled off under reduced pressure to obtain a crude product. By purifying the crude product by silica gel column chromatography (developing solvent: hexane-chloroform mixed solvent), Exemplified Compound No. 0.45 g (yield 42.1%) of 18 (Compound C-3) was obtained as a white solid.

The obtained Exemplified Compound No. For 18, the phosphorescence spectrum was measured in the same manner as in Example 1, was calculated T ₁ from the obtained phosphorescence spectrum. The results are shown in Table 3.

  Example 4 <Exemplary Compound No. Synthesis of 21>

  The following reagents and solvents were charged into a 200 ml three-necked flask.

Compound D-1: 2.0 g (2.2 mmol)
Pinacol borane compound (Compound D-2): 0.3 g (1.1 mmol)
Toluene: 80ml
Ethanol: 20ml

  Next, while stirring the reaction solution at room temperature under a nitrogen atmosphere, 20 ml of a saturated sodium carbonate aqueous solution was added, and then 0.25 g (0.22 mmol) of tetrakis (triphenylphosphine) palladium (0) was added. . Next, the reaction solution was stirred at room temperature for 30 minutes, and then stirred for 18 hours while refluxing the reaction solution. After completion of the reaction, the organic layer was extracted with chloroform and dried, and then the solvent was distilled off under reduced pressure to obtain a crude product. By purifying the crude product by silica gel column chromatography (developing solvent: hexane-chloroform mixed solvent), Exemplified Compound No. Thus, 0.33 g (yield 14.9%) of 21 (Compound D-3) was obtained as a white solid.

The obtained Exemplified Compound No. For 21, the phosphorescence spectrum was measured in the same manner as in Example 1, was calculated T ₁ from the obtained phosphorescence spectrum. The results are shown in Table 3.

[Comparative Example 1]
Comparative compound No. shown below. 1 2FL was measured for phosphorescence spectrum by the same method as in Example 1, and T ₁ was calculated from the obtained phosphorescence spectrum. The results are shown in Table 3.

[Comparative Example 2]
Comparative compound No. shown below. For 4FL, which was 2, the phosphorescence spectrum was measured in the same manner as in Example 1, and T ₁ was calculated from the obtained phosphorescence spectrum. The results are shown in Table 3. 4FL is oligofluorene described in JP-A-2003-055275.

[Comparative Example 3]
Comparative compound No. shown below. 3 9FL was measured for phosphorescence spectrum in the same manner as in Example 1, and T ₁ was calculated from the obtained phosphorescence spectrum. The results are shown in Table 3. 9FL is oligofluorene described in JP-A-2003-055275.

[Comparative Example 4]
Comparative compound No. shown below. Phosphorescence spectrum of poly (9,9-dioctyl) fluorene (PFL, manufactured by American Dye Source Inc., Mw = 80000), which is 4, was measured in the same manner as in Example 1. And calculating the T ₁ from phosphorescence spectrum obtained by the measurement. The results are shown in Table 3.

As shown in Table 3, T ₁ of 2FL that are linked by a single bond and a 2-position substituent and 2-position substituent as bond is 2.48 eV, as compared to the fluorene compound of the present invention It was a low value. It was also found that T ₁ tends to decrease as fluorene to be linked increases.

[Example 5]
An organic electroluminescent element having the structure shown in FIG.

  On the glass substrate (transparent substrate 15), indium tin oxide (ITO) was formed by sputtering to form the transparent electrode 14. At this time, the film thickness of the transparent electrode 14 was 120 nm. This was ultrasonically washed successively with acetone and isopropyl alcohol (IPA), then boiled and washed with IPA and then dried. Further, UV / ozone cleaning was performed. The substrate treated as described above was used as a transparent conductive support substrate.

  Next, on this transparent conductive support substrate, Vitron PAl-4083 (manufactured by Starck) was formed by spin coating to form a hole injection / transport layer 13. At this time, the thickness of the hole injection / transport layer 13 was set to 50 nm.

  Next, a chloroform solution of polyvinyl carbazole (PVK, manufactured by Aldrich) was prepared. Next, this solution was dropped on the hole injection / transport layer 13 in a nitrogen atmosphere and spin-coated at a rotational speed of 2000 for 2 minutes. Next, the interlayer layer 16 was formed by drying in a drier set to 200 ° C. At this time, the thickness of the interlayer layer 16 was 200 mm.

Next, Exemplified Compound No. which is a host. 14 and an Ir complex (Ir (Cyppy) ₃ ) shown below as a guest were dissolved in toluene to prepare a 1 wt% toluene solution. At this time, the weight mixing ratio of the host and the guest was 98: 2. Ir (Cyppy) ₃ is an Ir complex obtained according to the synthesis method described in JP-A-2002-359079, has an emission peak wavelength of 524 nm, and T ₁ is 2.50 eV.

  Next, the toluene solution was dropped on the interlayer layer 16 to form a light emitting layer 12 by spin coating. At this time, the thickness of the light emitting layer 12 was set to 60 nm.

Next, calcium was deposited by vacuum deposition to form a metal layer film to be the electron injection / transport layer 11. At this time, the thickness of the electron injecting / transporting layer 11 was 1 nm, the degree of vacuum during vapor deposition was 1.0 × 10 ⁻⁴ Pa, and the film formation rate was 0.1 nm / sec.

Next, aluminum was formed into a film by a vacuum evaporation method, and the metal electrode 10 was formed. At this time, the film thickness of the metal electrode 10 was 150 nm, the degree of vacuum during vapor deposition was 1.0 × 10 ⁻⁴ Pa, and the film formation rate was 1.0 nm / sec or more and 1.2 nm / sec or less.

  Next, a protective glass plate was placed under a nitrogen atmosphere and sealed with an acrylic resin adhesive. An organic electroluminescent element was obtained as described above.

For the obtained device, when an ITO electrode (transparent electrode 14) was used as a positive electrode and an Al electrode (metal electrode 10) was used as a negative electrode and a DC voltage of 8 V was applied, a current flowed through the device. The current density at this time was 30 mA / cm ² , and green light emission with a luminance of 7000 cd / m ² was observed. In this device, the current efficiency was 30 cd / A, the peak of the emission spectrum was 524 nm, and the CIE chromaticity coordinates were (x, y) = (0.31, 0.64).

Furthermore, when the luminance durability test was performed under the condition of an initial luminance of 1000 cd / m ² , the luminance half time (time until the luminance was reduced to 500 cd / m ² ) was 60 hours.

[Example 6]
In Example 5, the host of the light-emitting layer 12 was designated as Exemplified Compound No. In place of Example Compound No. 14 A device was fabricated in the same manner as in Example 5 except that the number was 17. The obtained device was evaluated in the same manner as in Example 5. The results are shown in Table 4.

[Example 7]
In Example 5, the host of the light-emitting layer 12 was designated as Exemplified Compound No. In place of Example Compound No. 14 A device was produced in the same manner as in Example 5 except that the number was 18. The obtained device was evaluated in the same manner as in Example 5. The results are shown in Table 4.

[Example 8]
In Example 5, the host of the light-emitting layer 12 was designated as Exemplified Compound No. In place of Example Compound No. 14 A device was fabricated in the same manner as in Example 5 except that the number was 21. The obtained device was evaluated in the same manner as in Example 5. The results are shown in Table 4.

[Comparative Example 5]
In Example 5, the host of the light-emitting layer 12 was designated as Exemplified Compound No. In place of Comparative Compound No. 14 A device was fabricated in the same manner as in Example 5 except that 1 (2FL) was used. The obtained device was evaluated in the same manner as in Example 5. The results are shown in Table 4.

[Comparative Example 6]
In Example 5, the host of the light-emitting layer 12 was designated as Exemplified Compound No. In place of Comparative Compound No. 14 A device was fabricated in the same manner as in Example 5 except that 2 (4FL) was used. The obtained device was evaluated in the same manner as in Example 5. The results are shown in Table 4.

[Comparative Example 7]
In Example 5, the host of the light-emitting layer 12 was designated as Exemplified Compound No. In place of Comparative Compound No. 14 A device was fabricated in the same manner as in Example 5 except that 3 (9FL) was used. The obtained device was evaluated in the same manner as in Example 5. The results are shown in Table 4.

[Comparative Example 8]
In Example 5, the host of the light-emitting layer 12 was designated as Exemplified Compound No. In place of Comparative Compound No. 14 A device was fabricated in the same manner as in Example 5 except that 4 (PFL) was used. The obtained device was evaluated in the same manner as in Example 5. The results are shown in Table 4.

Table 4 shows that when the fluorene compound of the present invention is used as a host of the light emitting layer, the obtained organic electroluminescent element has both high efficiency and high durability. On the other hand, Comparative Compound No. When 1 to 4 were used as the host of the light emitting layer, it was shown that the obtained organic electroluminescent device was not highly efficient and low in durability. This is because a host material smaller than T ₁ (2.50 eV) of Ir (Cyppy) ₃ that is a guest is used, so that a phenomenon in which triplet excitation energy flows into the host side (back energy transfer phenomenon) occurred. Conceivable.

[Example 9]
In Example 5, Exemplified Compound No. 14 was prepared in the same manner as in Example 5, except that a 1 wt% toluene solution of 14 was prepared and this toluene solution was dropped on the interlayer layer 16 to form a light emitting layer 12 by spin coating. did. The obtained device was evaluated in the same manner as in Example 5. In the luminance durability experiment, the initial luminance was set to 200 cd / m ² . The results are shown in Table 5.

[Example 10]
In Example 5, Exemplified Compound No. 17 was prepared in the same manner as in Example 5 except that a 1 wt% toluene solution was prepared, and this toluene solution was dropped on the interlayer layer 16 to form a light emitting layer 12 by spin coating. did. The obtained device was evaluated in the same manner as in Example 5. In the luminance durability experiment, the initial luminance was set to 200 cd / m ² . The results are shown in Table 5.

[Example 11]
In Example 5, Exemplified Compound No. 18 was prepared in the same manner as in Example 5 except that a 1 wt% toluene solution was prepared and this toluene solution was dropped on the interlayer layer 16 to form a light emitting layer 12 by spin coating. did. The obtained device was evaluated in the same manner as in Example 5. In the luminance durability experiment, the initial luminance was set to 200 cd / m ² . The results are shown in Table 5.

[Example 12]
In Example 5, Exemplified Compound No. A device was fabricated in the same manner as in Example 5 except that a 1 wt% toluene solution of No. 21 was prepared, and this toluene solution was dropped on the interlayer layer 16 to form the light emitting layer 12 by spin coating. did. The obtained device was evaluated in the same manner as in Example 5. In the luminance durability experiment, the initial luminance was set to 200 cd / m ² . The results are shown in Table 5.

[Example 13]
An organic electroluminescent element having the structure shown in FIG.

  A compound represented by the following formula (bis (difluorenylamino) -2,7-fluorene, hereinafter abbreviated as BDFF) is vacuum-deposited on a transparent conductive support substrate treated in the same manner as in Example 5. The hole injection / transport layer 13 was formed by film formation. At this time, the thickness of the hole injection / transport layer 13 was set to 30 nm.

Next, Exemplified Compound No. which is a host by vacuum deposition is used. 14 and an Ir complex (Ir (ppy) ₃ ) represented by the following formula, which is a guest, are co-deposited so that the deposition rate ratio is [host]: [guest] = 5 nm / sec: 0.1 nm / sec. Thus, the light emitting layer 12 was formed. At this time, the thickness of the light emitting layer 12 was set to 50 nm, and the degree of vacuum at the time of vapor deposition was set to 1.0 × 10 ⁻⁴ Pa.

  Next, the electron injection / transport layer 11 was formed by vapor-depositing BCP (basocupline, a product obtained by sublimation purification from Aldrich) by vacuum deposition. At this time, the thickness of the electron injection / transport layer 11 was set to 25 nm.

Next, a vapor deposition material (lithium concentration: 1 atomic%) composed of aluminum and lithium was deposited on the electron injection / transport layer 11 by a vacuum deposition method to form a metal layer film (aluminum-lithium film). At this time, the thickness of the aluminum-lithium film was set to 50 nm, the degree of vacuum at the time of vapor deposition was set to 1.0 × 10 ⁻⁴ Pa, and the film formation rate was set to 1.0 nm / sec or more and 1.2 nm / sec or less. Next, aluminum was deposited by a vacuum deposition method to form a metal layer film (aluminum film). At this time, the film thickness of the aluminum film was 150 nm, the degree of vacuum during vapor deposition was 1.0 × 10 ⁻⁴ Pa, and the film formation rate was 1.0 nm / sec or more and 1.2 nm / sec or less. Here, the aluminum-lithium film and the aluminum film function as the metal electrode 10. Finally, an organic electroluminescent element was obtained by sealing in the same manner as in Example 5.

About the obtained element, when an ITO electrode (transparent electrode 14) was a positive electrode and an Al electrode (metal electrode 10) was a negative electrode and a DC voltage of 6 V was applied, a current flowed through the element. The current density at this time was 30 mA / cm ² , and green light emission with a luminance of 11050 cd / m ² was observed. In this device, the current efficiency was 40 cd / A, the peak of the emission spectrum was 515 nm, and the CIE chromaticity coordinates were (x, y) = (0.32, 0.63). Furthermore, when the luminance durability test was performed with an initial luminance of 1000 cd / m ² , the luminance half time (time until the luminance was reduced to 500 cd / m ² ) was 140 hours.

[Example 14]
In Example 13, the host of the light-emitting layer 12 was treated with Exemplified Compound No. In place of Example Compound No. 14 A device was fabricated in the same manner as in Example 13 except that the number was 17. The obtained device was evaluated in the same manner as in Example 13. The results are shown in Table 6.

[Example 15]
An organic electroluminescent element having the structure shown in FIG.

  On the transparent conductive support substrate treated in the same manner as in Example 5, Vitron PAl-4083 (manufactured by Starck) was formed by spin coating to form the hole injection / transport layer 13. At this time, the thickness of the hole injection / transport layer 13 was set to 50 nm.

Next, Exemplified Compound No. which is a host. 14 and an Ir complex (Ir (C ₈ -piq) ₃ ) shown below as a guest were dissolved in toluene to prepare a 1 wt% toluene solution. At this time, the weight concentration ratio between the host and the guest was 98: 2. Ir (C ₈ -piq) ₃ is an Ir complex having an emission peak at 618 nm.

  Next, this light emitting layer 12 was formed by dripping this toluene solution on the hole injection / transport layer 13, and forming into a film by a spin coat method. At this time, the thickness of the light emitting layer 12 was set to 60 nm.

Next, a metal layer film to be the electron injection / transport layer 11 was formed by depositing calcium on the light emitting layer 12 by vacuum deposition. At this time, the thickness of the electron injecting / transporting layer 11 was 1 nm, the degree of vacuum during vapor deposition was 1.0 × 10 ⁻⁴ Pa, and the film formation rate was 0.1 nm / sec.

Next, the metal electrode 10 was formed by depositing aluminum on the electron injection / transport layer 11 by a vacuum deposition method. At this time, the film thickness of the metal electrode 10 was 150 nm, the degree of vacuum during vapor deposition was 1.0 × 10 ⁻⁴ Pa, and the film formation rate was 1.0 nm / sec or more and 1.2 nm / sec or less.

  Finally, sealing was performed in the same manner as in Example 5. The organic electroluminescent element was obtained by the above.

With respect to the obtained element, when a direct current voltage of 5.5 V was applied with the ITO electrode (transparent electrode 14) as the positive electrode and the Al electrode (metal electrode 10) as the negative electrode, a current flowed through the element. At this time, the current density was 30 mA / cm ² , and red light emission with a luminance of 1550 cd / m ² was observed. In this device, the current efficiency was 7.5 cd / A, the peak of the emission spectrum was 618 nm, and the CIE chromaticity coordinates were (x, y) = (0.67, 0.32). Furthermore, when the luminance durability test was performed with the initial luminance set at 500 cd / m ² , the luminance half time (the time required for the luminance to become half of 250 cd / m ² ) was 250 hours.

[Example 16]
In Example 15, the host of the light-emitting layer 12 was treated with Exemplified Compound No. In place of Example Compound No. 14 A device was fabricated in the same manner as in Example 15 except that the number was 17. The obtained device was evaluated in the same manner as in Example 15. The results are shown in Table 6.

[Example 17]
In Example 15, the host of the light-emitting layer 12 was treated with Exemplified Compound No. In place of Example Compound No. 14 A device was fabricated in the same manner as in Example 15 except that the number was 18. The obtained device was evaluated in the same manner as in Example 15. The results are shown in Table 6.

[Example 18]
In Example 15, the host of the light-emitting layer 12 was treated with Exemplified Compound No. In place of Example Compound No. 14 A device was fabricated in the same manner as in Example 15 except that the number was 21. The obtained device was evaluated in the same manner as in Example 15. The results are shown in Table 6.

[Example 19]
In Example 15, the host of the light-emitting layer 12 was treated with Exemplified Compound No. In place of Example Compound No. 14 A device was fabricated in the same manner as in Example 15 except that a mixture of 14 and BDFF which is a hole transporting compound (weight concentration ratio: 4/1) was used. The obtained device was evaluated in the same manner as in Example 15. The results are shown in Table 6.

[Example 20]
An organic electroluminescent element having the structure shown in FIG.

  First, a glass substrate was processed in the same manner as in Example 5 to obtain a transparent conductive support substrate.

  Next, the following compounds were dissolved in toluene to prepare a 1 wt% toluene solution.

Ir complex _{(Ir (C 8 -piq) 3} ): 0.4 parts by weight Exemplified Compound No. 21: 19.6 parts by weight PFB (poly (9,9-dioctylfluorene-2,7-diyl-co-bis-N, N '-(4-butylphenyl) -bis-) is a hole transport compound shown below. N, N′-phenyl-1,4-phenylenediamine): 50 parts by weight

    PBD (2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole), which is an electron transport compound shown below: 30 parts by weight

  In addition, PFB refine | purified and used the commercial item (Mw = 100000) by Sands. PBD was obtained by sublimation purification using a commercial product manufactured by Aldrich.

  Next, this toluene solution was dropped on a transparent conductive support substrate, and a light emitting layer 12 was formed by forming a film by spin coating. At this time, the thickness of the light emitting layer 12 was set to 60 nm.

Next, a first metal layer film was formed by depositing a deposition material (lithium concentration of 1 atomic%) made of aluminum and lithium on the light emitting layer 12 by a vacuum deposition method. At this time, the thickness of the first metal layer film is 50 nm, the degree of vacuum at the time of vapor deposition is 1.0 × 10 ⁻⁴ Pa, and the film formation rate is 1.0 nm / sec or more and 1.2 nm / sec or less. did. Next, a second metal layer film was formed by depositing aluminum by a vacuum deposition method. At this time, the thickness of the second metal layer film is 150 nm, the degree of vacuum at the time of vapor deposition is 1.0 × 10 ⁻⁴ Pa, and the film formation rate is 1.0 nm / sec or more and 1.2 nm / sec or less. did. The first metal layer film and the second metal layer film function as the metal electrode 10.

  Finally, sealing was performed in the same manner as in Example 5. The organic electroluminescent element was obtained by the above.

About the obtained element, when an ITO electrode (transparent electrode 14) was a positive electrode and an Al electrode (metal electrode 10) was a negative electrode and a DC voltage of 6 V was applied, a current flowed through the element. The current density at this time was 30 mA / cm ² , and red light emission with a luminance of 1000 cd / m ² was observed. In this device, the current efficiency was 4 cd / A, the peak of the emission spectrum was 623 nm, and the CIE chromaticity coordinates were (x, y) = (0.68, 0.32). Furthermore, when the luminance durability test was performed with the initial luminance set at 500 cd / m ² , the luminance half time (the time required for the luminance to become half of 250 cd / m ² ) was 5 hours.

It is sectional drawing which shows the example of embodiment in the organic electroluminescent element of this invention, (a) is sectional drawing which shows 1st embodiment, (b) is sectional drawing which shows 2nd embodiment. (C) is sectional drawing which shows 3rd embodiment. It is a figure which shows typically the structural example of the display apparatus provided with the organic electroluminescent element and drive means of this invention which are one form of a display apparatus. FIG. 3 is a circuit diagram showing a circuit constituting one pixel arranged in the display device of FIG. 2. It is a schematic diagram which shows an example of the cross-sectional structure of the TFT substrate used with the display apparatus of FIG.

Explanation of symbols

1, 2, 3 Organic electroluminescent device 10 Metal electrode 11 Electron injection / transport layer 12 Light emitting layer 13 Hole injection / transport layer 14 Transparent electrode 15 Transparent substrate 16 Interlayer layer 17 Multifunctional light emitting layer 20, 40 Display device 21 Scan signal Driver 22 Information signal driver 23 Current supply source 24, 30 Pixel circuit 31 First thin film transistor (TFT1)
32 condenser (C _add )
33 Second thin film transistor (TFT2)
41 Substrate 42 Moisture-proof layer 43 Gate electrode 44 Gate insulating film 45 Semiconductor film 46 Drain electrode 47 Source electrode 48 TFT element 49 Insulating film 50 Contact hole (through hole)
51 Anode 52 Organic Layer 53 Cathode 54 First Protective Layer 55 Second Protective Layer

Claims (12)

A fluorene compound represented by the following general formula [I]:

(In the formula [I], n represents an integer of 1 to 20.)
R _{1 to} R ₆ each represents an alkyl group.
R ₇ represents a bond, a hydrogen atom or an alkyl group linking the R ₁₆ or R _17. However, when R ₈ is a bond, R ₇ represents a hydrogen atom.
R ₈ represents any one connected to bond, hydrogen atom or an alkyl group of R ₁₆ to R _18. However, when R ₇ or R ₉ is a bond, R ₈ represents a hydrogen atom.
R ₉ represents any one connected to bond, hydrogen atom or an alkyl group of R ₁₆ to R _18. However, when R ₈ is a bond, R ₉ represents a hydrogen atom.
Any one of R _{7 to} R ₉ is a bond.
R ₁₃ is a bond connected to R ₁₆ , R ₁₇ , R ₂₂ or R ₂₃ , a hydrogen atom, or a substituent shown below.

(* Represents a bond.)
Represents.
R ₁₄ represents a bond, a hydrogen atom or a substituent shown below that is linked to any one of R _{16 to} R ₁₈ and R _{22 to} R _24.

(* Represents a bond.)
Represents.
R ₁₅ represents a bond, a hydrogen atom, or a substituent shown below that is linked to any one of R _{16 to} R ₁₈ and R _{22 to} R _24.

(* Represents a bond.)
Represents.
One of R _{13 to} R ₁₅ is a bond.
R ₁₆ represents a bond, a hydrogen atom, or a substituent shown below that is linked to any one of R _{7 to} R ₉ and R _{13 to} R _15.

(* Represents a bond.)
Represents.
R ₁₇ represents a bond, a hydrogen atom, or a substituent shown below , linked to any one of R _{7 to} R ₉ and R _{13 to} R _15.

(* Represents a bond.)
Represents.
R ₁₈ represents a bond, a hydrogen atom, or a substituent shown below , linked to any one of R ₈ , R ₉ , R ₁₄ and R _15.

(* Represents a bond.)
Represents.
Any one of R _{16 to} R ₁₈ is a bond.
R ₂₂ represents a bond, a hydrogen atom or an alkyl group of any one connection of R ₁₃ to R _15. However, when R ₂₃ is a bond, R ₂₂ represents a hydrogen atom.
R ₂₃ represents a bond, a hydrogen atom or an alkyl group of any one connection of R ₁₃ to R _15. However, when R ₂₄ or R ₂₂ is a bond, R ₂₃ represents a hydrogen atom.
R ₂₄ represents a bond, a hydrogen atom or an alkyl group linking the R ₁₄ or R _15. However, if R ₂₃ is a bond, R ₂₄ represents a hydrogen atom.
One of R _{22 to} R ₂₄ is a bond.
R _{10 to} R ₁₂ and R _{19 to} R ₂₁ each represent a hydrogen atom or an alkyl group . ) The alkyl group is a propyl group, isopropyl group, butyl group, isobutyl group, secondary butyl group, tertiary butyl group, butyl group, pentyl group, isopentyl group, hexyl group, cyclopropyl group, cyclopentyl group or cyclohexyl group. The fluorene compound according to claim 1, wherein the fluorene compound is a substituent selected from: The fluorene compound according to claim 1 or 2 , wherein the triplet excitation energy level obtained from the emission end of the phosphorescence spectrum is 2.5 eV or more. The fluorene compound according to any one of claims 1 to 3 , wherein n is 1. Wherein R ₁ to R ₆ is a substituent each selected from methyl, ethyl and isopentyl group,
R ₇ is a hydrogen atom or a bond linked to R ₁₇ ;
R ₈ is a hydrogen atom or a bond linked to R ₁₇ or R ₁₈ ;
R ₉ is a hydrogen atom or a bond linked to R ₁₆ , R ₁₇ or R ₁₈ ;
R ₁₃ is a hydrogen atom, a substituent shown below

(* Represents a bond.)
Or a bond linked to R ₂₂ or R ₂₃ ,
R ₁₄ is a hydrogen atom, a substituent shown below

(* Represents a bond.)
Or a bond linked to R ₂₂ , R ₂₃ or R ₂₄ ,
R ₁₅ is a hydrogen atom group or a bond linked to R ₂₂ , R ₂₃ or R ₂₄ ;
R ₁₆ is a hydrogen atom or a bond linked to R ₉ ;
R ₁₇ is a hydrogen atom, a substituent shown below

(* Represents a bond.)
Or a bond linked to R ₇ ,
R ₁₈ is a hydrogen atom, a substituent shown below

(* Represents a bond.)
Or a bond linked to R ₈ or R ₉ ,
R ₂₂ is a hydrogen atom or a bond linked to R ₁₃ , R ₁₄ or R ₁₅ ;
R ₂₃ is a hydrogen atom or a bond linked to R ₁₃ , R ₁₄ or R ₁₅ ;
R ₂₄ is a hydrogen atom, a tertiary butyl group, or a bond linked to R ₁₄ or R ₁₅ ;
Wherein R ₁₀ to R ₁₂ are each hydrogen atom,
The fluorene compound according to claim 4 , wherein each of R _{19 to} R ₂₁ is a hydrogen atom or a tertiary butyl group. The fluorene compound according to any one of claims 1 to 3, wherein n is an integer of 2 to 15. R _{1 to} R ₆ are each a substituent selected from a methyl group, an ethyl group, an isopentyl group, and an n-hexyl group;
Wherein R ₇ is hydrogen atom or a tertiary butyl group,
R ₈ is a hydrogen atom or a bond linked to R ₁₈ ;
R ₉ is a hydrogen atom or a bond linked to R ₁₈ ;
R ₁₃ is a hydrogen atom , a substituent shown below

(* Represents a bond.)
Or a bond linked to R ₁₆ , R ₁₇ , R ₂₂ or R ₂₃ ,
R ₁₄ is a hydrogen atom , a substituent shown below

(* Represents a bond.)
Or a bond linking to R ₁₇ , R ₁₈ , R ₂₃ or R ₂₄ ,
R ₁₅ is a hydrogen atom or a bond linked to R ₁₈ ;
R ₁₆ is a hydrogen atom or a bond linked to R ₁₃ ;
R ₁₇ is a hydrogen atom , a substituent shown below

(* Represents a bond.)
Or a bond linked to R ₁₃ or R ₁₄ ,
R ₁₈ is a hydrogen atom , a substituent shown below

(* Represents a bond.)
Or a bond linked to R ₈ , R ₉ , R ₁₄ or R ₁₅ ,
R ₂₂ is a hydrogen atom or a bond linked to R ₁₃ , R ₁₄ or R ₁₅ ;
R ₂₃ is a hydrogen atom or a bond linked to R ₁₃ , R ₁₄ or R ₁₅ ;
R ₂₄ is a hydrogen atom, a tertiary butyl group, or a bond linked to R ₁₄ or R ₁₅ ;
Wherein R ₁₀ to R ₁₂ are each hydrogen atom or a tertiary butyl group,
Wherein R ₁₉ to R _21, characterized in that each a hydrogen atom or a tertiary butyl group, a fluorene compound according to claim 6. And characterized in that any of the compounds shown below, fluorene compound according to any one of claims 1 to 7.

An anode and a cathode;
A layer made of an organic compound sandwiched between the anode and the cathode,
An organic electroluminescent device comprising at least one kind of the fluorene compound according to any one of claims 1 to 8 in at least one layer of the organic compound. The organic electroluminescent device according to claim 9 , wherein the fluorene compound is contained in a light emitting layer. An ink composition comprising at least one fluorene compound according to any one of claims 1 to 8 . A display device using the organic electroluminescent element according to claim 9 .

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