JP2006257168A - Material for organic electroluminescent element, and organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a material for an organic electroluminescent element, having ultraviolet organic electroluminescent ability of ≤400 nm, and also having a good carrier transport property. <P>SOLUTION: The material for organic electroluminescent element contains at least one kind of a compound selected from the compounds represented by general formulas (1) to (7) (wherein, Sp is a spirobifluorene having a substituent such as a 1-8C alkyl group and a halogen). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an organic electroluminescent element material and an organic electroluminescent element using a spirobifluorene compound. In particular, the present invention relates to a material for an organic electroluminescence device having an ultraviolet organic electroluminescence ability having a maximum wavelength of 400 nm or less, and an organic electroluminescence device using the same and emitting ultraviolet light having a high emission efficiency and a maximum wavelength of 400 nm or less.

  Spirofluorene compounds have a unique steric structure. First, pi-stacking with adjacent compounds is hindered, and exciton interaction is reduced, resulting in a reduction in luminous efficiency. Second, It is known as a material for an organic electroluminescence device having characteristics such as that crystallization is hindered and thin film stability is increased (for example, see Patent Document 1). However, these materials are intended to provide a spirobifluorene compound having a conjugated system as a material for an organic electroluminescence device in order to emit visible light. In order to emit ultraviolet light instead of visible light emission, it is necessary to prevent the conjugated system from spreading. However, a spirobifluorene compound having only a bond with an alkylene chain having no phenyl group or the like has carrier transportability. There is a problem that the luminous efficiency is greatly reduced.

  Further, spirobifluorene compounds bonded to anthracene are known (for example, see Patent Document 2). However, this compound is also intended to provide a material for an organic electroluminescent element that emits visible light by widening the conjugation.

  On the other hand, a photochromic element that uses light emitted from an electroluminescent element as excitation light has been proposed (see, for example, Patent Document 3). When the excitation light is visible light, the color of the excitation light and the color of the photochromic element are mixed, making it difficult to perform a vivid display. For this reason, there is a need for an electroluminescent device having ultraviolet light emission instead of the visible light emission conventionally required for materials for organic electroluminescent devices. Examples of the organic compound used in the organic electroluminescence device having ultraviolet emission include, for example, linearly linked polyphenyl such as p-quarterphenyl, silane polymer, phenylene vinylene polymer, 4,4′- Bis (9-carbazoyl) biphenyl is known (see, for example, Patent Documents 4 to 6 and Non-Patent Documents 1 and 2). However, there has been no organic electroluminescent element material having an ultraviolet organic electroluminescent ability having a maximum wavelength of 400 nm or less, and having good carrier transportability and thin film stability.

Japanese Patent Application Laid-Open No. 07-278537 JP 2002-121547 A JP 2004-264424 A Japanese Patent Laid-Open No. 3-152897 Japanese Patent Laid-Open No. 2001-167585 Japanese Patent Application Laid-Open No. 07-278537 “Journal of Applied Physics” 2000, No. 88, p. 2892 “Applied Physics Letters” 2001, No. 79, p. 2282

  An object of the present invention is to provide an organic electroluminescent element material having an ultraviolet organic electroluminescent ability having a maximum wavelength of 400 nm or less and having a good carrier transportability.

The present inventors have found that a specific compound satisfies these objectives by synthesizing various spirobifluorene compounds and measuring their organic electroluminescent ability and thermal stability in the ultraviolet region. It came to be completed.
That is, the present invention relates to the general formulas (1) to (7).

（ここで、Ｓｐは次式

(Where Sp is

で示される官能基を表し、但し、Ｘ₁〜Ｘ₄はそれぞれ独立して炭素原子数１〜８のアルキル基または、ハロゲン原子または、シアノ基を表し、一般式（１）〜（７）の有するベンゼン環又はナフタレン環が有する水素原子は、炭素原子数１〜８のアルキル基で置換されていても良い。）
から選ばれる少なくとも一種の化合物を含有する有機電界発光素子用材料を提供する。

In which X _{1 to} X ₄ each independently represents an alkyl group having 1 to 8 carbon atoms, a halogen atom, or a cyano group, and represented by the general formulas (1) to (7) The hydrogen atom that the benzene ring or naphthalene ring has may be substituted with an alkyl group having 1 to 8 carbon atoms. )
The material for organic electroluminescent elements containing at least 1 type of compound chosen from is provided.

  The material for an organic electroluminescent element of the present invention is useful as a material for an organic electroluminescent element that emits ultraviolet light. In addition, an organic electroluminescent element that emits ultraviolet light can provide a photochromic display element having memory properties in combination with a photochromic material that absorbs and colors ultraviolet light.

Hereinafter, the invention will be described in detail.
(Compounds represented by the general formulas (1) to (7))
The organic electroluminescent element material of the present invention contains at least one compound selected from the compounds represented by formulas (1) to (7) (hereinafter referred to as compound (1) to compound (7)). To do. These compounds have a structure in which 1 to 3 groups Sp (hereinafter referred to as Sp) substituted on a benzene ring or naphthalene ring are substituted. In order to emit ultraviolet light and not visible light, it preferably has no conjugated structure with the group to which the substituent Sp is bonded. However, bonding with only a group having an alicyclic structure instead of a benzene ring or naphthalene ring results in poor carrier transportability and lowers luminous efficiency.
It has been found that a structure in which a plurality of Sps are substituted on a benzene ring or a naphthalene ring is preferable to a structure in which a plurality of aromatic rings are substituted on Sp in order to have ultraviolet emission ability and good luminous efficiency. Any compound in which Sp is substituted by 1 on the benzene ring or naphthalene ring has an organic electroluminescence ability with a maximum emission wavelength of 400 nm or less.

  Furthermore, when two or three Sps are substituted on the benzene ring, substitution to the meta position results in a structure in which conjugation is unlikely to occur (for example, compound (2), compound (3)), which is more preferable. I also found that.

  Moreover, when Sp substitutes for the naphthalene ring, both the α-substituted product and the β-substituted product have an organic electroluminescent ability with a maximum emission wavelength of 400 nm or less, but the β-substituted product is more preferable. This is preferable because it has a maximum emission wavelength at a low wavelength. In addition, when Sp 2 is substituted on the naphthalene ring, a spirobifluorene compound (for example, compound (6), compound (7)) which is a β-substituted compound is preferable.

  The following formula (8) disubstituted at the α-position of the naphthalene ring

（式中、Ｓｐは、一般式（１）におけるＳｐと同じ意味を有する。）で表される化合物（以下、化合物（８）と言う。）は、共役が広がり、図９に示すように最大発光波長が４１４ｎｍになってしまう。

(In the formula, Sp has the same meaning as Sp in the general formula (1).) The compound represented by the following (hereinafter referred to as the compound (8)) has a wide conjugation and has a maximum as shown in FIG. The emission wavelength is 414 nm.

  Hydrogen contained in the benzene ring and naphthalene ring of the compounds (1) to (7) may be substituted with an alkyl group having 1 to 8 carbon atoms, but a methyl group or a branched alkyl group is preferred. Examples of the branched alkyl group include an isobutyl group and a tert-butyl group. These groups are considered to have an effect of suppressing the association between spirobifluorenes.

The substituent of X _{1 to} X ₄ that Sp has is hydrogen, an alkyl group having 1 to 8 carbon atoms, a halogen atom, or a cyano group, preferably an alkyl group having 1 to 4 carbon atoms, and the halogen atom is And a fluorine atom is preferred.

(Synthesis Method of Compounds (1) to (3))
Compounds (1) to (3) are described in, for example, “Chemistry of Materials” 2002, No. 14, p. The compound can be produced by the following synthesis route using a known and conventional method described in 463.

（式中、Ｒ’は炭素原子数１〜８のアルキル基を表し、Ｘ１〜Ｘ４はそれぞれ独立してハロゲン原子、シアノ基、又は炭素原子数１〜８のアルキル基を表し、Ｙはハロゲン原子を表し、ｎは１〜３の整数を表し、ｍは０〜５の整数を表す。）

(In the formula, R ′ represents an alkyl group having 1 to 8 carbon atoms, X1 to X4 each independently represents a halogen atom, a cyano group, or an alkyl group having 1 to 8 carbon atoms, and Y represents a halogen atom. N represents an integer of 1 to 3, and m represents an integer of 0 to 5.)

  Specifically, the spirobifluorene derivative having a boronic acid group and an aryl halide can be easily obtained by heating and stirring under a palladium catalyst. As the aryl halide, for example, iodide and bromide (Y in the above reaction formula respectively correspond to an iodine atom and a bromine atom) are preferably used. If necessary, chloride (in the above reaction formula) Y corresponds to a chlorine atom). For example, when obtaining the compound (2), 1,3-diiodobenzene is used as the aryl halide, and when obtaining the compound (3), 1,3,5- Use of triiodobenzene can be mentioned as a preferred embodiment.

  The compound (3) is, for example, “Journal of the American Chemical Society” 2003, No. 125, p. The compound can be synthesized by the following synthesis route using a known and commonly used technique described in 12430.

（式中、Ｒは水素原子または炭素原子数１〜８のアルキル基を表し、Ｘ₁〜Ｘ₄は式（１）中におけるＸ₁〜Ｘ₄と同じ意味を表す。）本合成ルートを用いた化合物（３）（Ｒ：水素原子、Ｘ１〜Ｘ４：水素原子の場合）の合成方法をより詳細に下記に示す。

Use (wherein, R represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, X ₁ to X ₄ have the same meanings as X ₁ to X ₄ in the formula (1).) The present synthetic route The synthesis method of Compound (3) (R: hydrogen atom, X1 to X4: hydrogen atom) is shown in more detail below.

  Specifically, for example, “Journal of the Organic Chemistry” 2002, No. 67, p. A spirobifluorene compound having an acetyl group is obtained by the method described in 4924, and this is mixed with an ethanol / toluene mixed solvent in the presence of silicon tetrachloride under an inert gas atmosphere such as nitrogen, argon, helium, etc. It can be obtained by heating and stirring at reflux temperature.

(Synthesis Method of Compounds (4) to (7))
Compounds (4) to (7) are described in, for example, “Chemistry of Materials” 2002, No. 14, p. The compound can be produced by the following synthesis route using a known and conventional method described in 463.

（式中、Ｒ”は炭素原子数１〜８のアルキル基を表し、Ｘ１〜Ｘ４はそれぞれ独立してハロゲン原子、シアノ基、又は炭素原子数１〜８のアルキル基を表し、Ｙはハロゲン原子を表し、ｎは１〜２の整数を表し、ｍは０〜６の整数を表す。）

(Wherein R ″ represents an alkyl group having 1 to 8 carbon atoms, X1 to X4 each independently represents a halogen atom, a cyano group, or an alkyl group having 1 to 8 carbon atoms, and Y represents a halogen atom. N represents an integer of 1 to 2, and m represents an integer of 0 to 6.)

  Specifically, it can be easily obtained by heating and stirring a spirobifluorene derivative having halogen and a naphthalene derivative having a boronic acid group under a palladium catalyst. As the halogen atom, an iodine atom or a bromine atom is preferably used, but chlorine is also used if necessary. For example, when obtaining a compound (4), it is preferable to make it react using 2-bromo-9,9'-spirobifluorene and 2-naphthalene boronic acid. Moreover, when obtaining a compound (5), it is preferable to make it react using 2-bromo-9,9'-spirobifluorene and 1-naphthalene boronic acid.

(Ultraviolet organic electroluminescence characteristics and thermal characteristics of compounds (1) to (7))
Compounds (1) to (7) have an ultraviolet organic electroluminescence ability with a maximum wavelength of 400 nm or less. The maximum organic electroluminescence wavelength is preferably 380 nm or less, and more preferably 370 nm or less.
X _{1 to} X ₄ in the general formulas (1) to (7) are hydrogen atom, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, tert-butyl group, octyl group, fluorine Atoms are preferred, and hydrogen atoms are most preferred in view of the manufacturing process and thermal stability. Although the hydrogen atom which the benzene ring or naphthalene ring which general formula (1)-(7) has may be substituted by the C1-C8 alkyl group, when a manufacturing process and thermal stability are considered, Unsubstituted products are preferred.

(Glass transition temperature of compounds (1) to (7))
Since the compounds (1) to (7) have a unique steric structure derived from a spirobifluorene group, they exhibit a high glass transition temperature, and as a result, have high thin film stability. The compound (2) which is the Sp disubstituted compound has a glass transition temperature higher than that of the monosubstituted compound (1), and the compound (3) which is the Sp trisubstituted compound has a glass transition higher than that of the disubstituted compound (2). The temperature is high. Compounds (4) and (5) in which the ring to which the Sp group is bonded are naphthalene have a glass transition temperature higher than that of the compound (1) in which the ring to which the Sp group is bonded is benzene. Sp disubstituted naphthalene is preferable because the thermal stability is further improved. Therefore, from the viewpoint of thermal stability, the compounds (2), (3), (4), (5), (6) and (7) are preferable, and the compounds (3), (6) and (7) are more preferable. Particularly preferred.

(Materials for organic electroluminescent elements)
The organic electroluminescent element material containing the spirobifluorene compound of the present invention can be provided by dissolving the compounds (1) to (7) in an appropriate organic solvent in the film formation by the coating method. Furthermore, it can also be provided in combination with a suitable organic solvent and binder resin.
Examples of the organic solvent include toluene, xylene, cyclohexanone, chlorobenzene, o-dichlorobenzene, tetralin, 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane, butyl carbitol and the like. These organic solvents can be used alone or in combination.
The binder resin can be selected from a wide range of binder resins such as polyvinyl carbazole resin, polycarbonate resin, polyester resin, polyarylate resin, polystyrene resin, acrylic resin, methacrylic resin, butyral resin, polyvinyl acetal resin, diallyl phthalate. Resins, phenol resins, epoxy resins, silicone resins, polysulfone resins, urea resins and the like can be mentioned, but are not limited thereto. Moreover, you may mix these 1 type, or 2 or more types as a single or copolymer polymer.

(UV organic electroluminescence device)
The organic electroluminescent element which has the organic electroluminescent element material of this invention between the opposing anode and cathode can be provided. A hole transport layer is formed on the anode by a method such as vapor deposition or spin coating, the organic electroluminescence device material of the present invention is vapor deposited or spin coated on the hole transport layer as a light emitting layer, and an electron is formed on the light emitting layer. An organic electroluminescent element can be manufactured by forming a transport layer and further forming a buffer layer on the electron transport layer. However, these element structures are very basic element structures, and the structure of the organic light emitting element using the organic electroluminescent element material of the present invention is not limited thereto. 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 at the interface between the electrode and the organic layer, and the hole transport layer is composed of two layers having different ionization potentials. Various layer configurations such as providing a hole injection layer and providing a hole block layer between the light emitting layer and the electron transport layer can be employed. In addition, it is preferable that the organic electroluminescent element of these structures is supported by the substrate. The substrate is not particularly limited, and those conventionally used in conventional organic electroluminescent elements, for example, those made of glass, transparent plastic, quartz and the like can be used. From the viewpoint of efficiently extracting light emitted from the organic light emitting layer, it is preferable to form at least one of the anode and the cathode with a transparent or translucent material. Note that a protective layer or a sealing layer can be provided on the prepared element for the purpose of preventing contact with oxygen or moisture. Examples of protective layers include diamond thin films, inorganic material films such as metal oxides and metal nitrides, polymer films such as fluororesins, polyparaxylene, polyethylene, silicone resins, and polystyrene resins, and photocurable resins. Can be mentioned. Further, it is possible to cover glass, a gas impermeable film, a metal, etc., and to package the element itself with an appropriate sealing resin.

(Anode material)
As the anode material, one having a work function as large as possible is preferable. For example, simple metals such as gold, platinum, nickel, palladium, cobalt, selenium, vanadium or alloys thereof, tin oxide, zinc oxide, indium tin oxide (ITO) A metal oxide such as zinc indium oxide 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.

(Hole transport layer material)
The hole transport layer material has the ability to transport holes, has a hole injection effect from the anode, an excellent hole injection effect for the light emitting layer or the light emitting material, and an electron transport layer for excitons generated in the light emitting layer Or the compound which prevents the movement to an electron injection material and was excellent in the thin film formation capability is preferable. Specifically, phthalocyanine derivatives, naphthalocyanine derivatives, porphyrin derivatives, oxazole, oxadiazole, triazole, imidazole, imidazolone, imidazolethione, pyrazoline, pyrazolone, tetrahydroimidazole, oxazole, oxadiazole, hydrazone, acylhydrazone, polyaryl Examples include alkane, stilbene, butadiene, benzidine type triphenylamine, styrylamine type triphenylamine, diamine type triphenylamine, and derivatives thereof, and polymer materials such as polyvinyl carbazole, polysilane, and conductive polymer. However, it is not limited to these.

Among these hole transport layer materials, more effective hole transport layer materials are aromatic tertiary amine derivatives or phthalocyanine derivatives. Specific examples of the aromatic tertiary amine derivative include triphenylamine, tolylamine, tolyldiphenylamine, N, N′-diphenyl-N, N ′-(3-methylphenyl) -1,1′-biphenyl-4, 4′-diamine, N, N, N ′, N ′-(4-methylphenyl) -1,1′-phenyl-4,4′-diamine, N, N, N ′, N ′-(4-methyl Phenyl) -1,1′-biphenyl-4,4′-diamine, N, N′-diphenyl-N, N′-dinaphthyl-1,1′-biphenyl-4,4′-diamine, N, N′- (Methylphenyl) -N, N ′-(4-n-butylphenyl) -phenanthrene-9,10-diamine, N, N-bis (4-di-4-tolylaminophenyl) -4-phenyl-cyclohexane, etc. Or oligomers having these aromatic tertiary amine skeletons Or is a polymer, but is not limited thereto. Specific examples of phthalocyanine (Pc) derivatives are H ₂ Pc, CuPc, CoPc, NiPc, ZnPc, PdPc, FePc, MnPc, ClAlPc, ClGaPc, ClInPc, ClSnPc, Cl ₂ SiPc, (HO) AlPc, (HO) GaPc, Although it is a phthalocyanine derivative and a naphthalocyanine derivative such as VOPc, TiOPc, MoOPc, and GaPc-O-GaPc, it is not limited thereto.

(Electron transport layer material)
The electron transport layer material has the ability to transport electrons, has an electron injection effect from the cathode, an excellent electron injection effect for the light emitting layer or the light emitting material, and a hole transport layer for excitons generated in the light emitting layer The compound which prevents the movement to and is excellent in thin film forming ability is preferable. Specifically, fluorenone, anthraquinodimethane, diphenoquinone, thiopyran dioxide, oxazole, oxadiazole, triazole, imidazole, perylenetetracarboxylic acid, quinoxaline, fluorenylidenemethane, anthraquinodimethane, anthrone, etc. However, it is not limited to these.

  Among these electron transport layer materials, a more effective electron transport material is a metal complex compound or a nitrogen-containing ring derivative. Specific examples of the metal complex compound include 8-hydroxyquinolinate lithium, bis (8-hydroxyquinolinato) zinc, bis (8-hydroxyquinolinato) copper, bis (8-hydroxyquinolinato) manganese, tris ( 8-hydroxyquinolinato) aluminum, tris (2-methyl-8-hydroxyquinolinato) aluminum, tris (8-hydroxyquinolinato) gallium, bis (10-hydroxybenzo [h] quinolinato) beryllium, bis ( 10-hydroxybenzo [h] quinolinato) zinc, bis (2-methyl-8-quinolinato) chlorogallium, bis (2-methyl-8-quinolinato) (o-cresolate) gallium, bis (2-methyl-8-quinolinato) ) (1-Naphtholate) aluminum, bis (2-methyl-8-) Norinato) (2-naphtholato) gallium and the like, but not limited thereto.

  As the nitrogen-containing ring derivative, an aromatic heterocyclic compound containing one or more hetero atoms in the molecule is preferably used. As a specific compound of the nitrogen-containing ring derivative, a compound having an azole skeleton which is a 5-membered ring is preferable. The compound having an azole skeleton is a compound having two or more atoms other than carbon atoms and hydrogen atoms in the basic skeleton, and may be a single ring or a condensed ring. The nitrogen-containing derivative preferably has two or more atoms selected from N, O and S atoms, more preferably has at least one N atom in the skeleton, and more preferably N atoms. In the skeleton. In addition, the heteroatom may be in a condensed position or a non-condensed position. Nitrogen-containing derivatives containing two or more heteroatoms include, for example, pyrazole, imidazole, pyrazine, pyrimidine, indazole, purine, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, perimidine, phenanthroline, pyrroloimidazole, pyrrolotriazole, pyrazoloro Imidazole, pyrazolotriazole, pyrazolopyrimidine, pyrazolotriazine, imidazoimidazole, imidazopyridazine, imidazopyridine, imidazopyrazine, triazolopyridine, benzimidazole, naphthimidazole, benzoxazole, naphthoxazole, benzothiazole, naphthothiazole, benzotriazole , Tetrazaindene, triazine and the like are preferable. Among these, as the electron transporting host material, a compound having a condensed azole skeleton such as imidazopyridazine, imidazopyridine, imidazopyrazine, benzimidazole, naphthimidazole, or a compound having a triazine skeleton is more preferable, and more preferable. Imidazopyridine.

(Inorganic compound layer material)
The organic electroluminescent element of the present invention may have an inorganic compound layer between at least one electrode and the organic thin film layer. Preferred inorganic compounds for use in the inorganic compound layer include alkali metal oxides, alkaline earth oxides, rare earth oxides, alkali metal halides, alkaline earth halides, rare earth halides, SiO _x , AlO _x , SiN. _{X, SiON, AlON, GeO X} , LiO X, LiON, TiO X, TiON, TaO X, TaON, TaN X, C and various oxides, nitrides, and oxide nitrides. In particular, as a component of the layer in contact with the anode, SiO _x , AlO _x , SiN _x , SiON, AlON, GeO _x , and C are preferable to form a stable injection interface layer. In particular, LiF, MgF ₂ , CaF ₂ , MgF ₂ , and NaF are preferred as the components of the layer in contact with the cathode.

(Cathode material)
The cathode material preferably has a small work function, and can be used as a single metal or a plurality of alloys such as lithium, sodium, potassium, cesium, calcium, magnesium, aluminum, indium, silver, lead, tin, and chromium. A metal oxide such as indium tin oxide (ITO) can also be used. Further, the cathode may have a single layer structure or a multilayer structure.

(Ultraviolet organic electroluminescent layer forming method)
In the organic light emitting device of the present invention, the layer containing the organic electroluminescent device material of the present invention generally forms a thin film by a vacuum deposition method when the organic electroluminescent device material of the present invention is a compound, When the organic electroluminescent element material of the present invention is provided in a form dissolved in an organic solvent, a thin film is formed by a coating method.

(Photochromic display element)
A photochromic device can be produced using the ultraviolet organic electroluminescent device of the present invention as an excitation light source. Photochromic display without coloring in the background can be performed due to excitation by ultraviolet light emission. This photochromic display element incorporates a photochromic layer inside or outside the ultraviolet organic electroluminescent element. As a preferred embodiment, a layer of the ultraviolet organic electroluminescent element material of the present invention is formed between a substrate having two electrodes, at least one of which is a transparent substrate having a transparent electrode, and the transparent substrate side of the transparent substrate Has a photochromic layer on the opposite side (that is, outside the ultraviolet organic electroluminescent device), a photochromic layer on the transparent electrode (that is, inside the ultraviolet organic electroluminescent device), or a transparent substrate An embodiment having a photochromic layer between the transparent electrode and the transparent electrode (that is, inside the ultraviolet organic electroluminescent element) can be mentioned.

  The photochromic layer may be in contact with the transparent electrode surface or the transparent substrate surface, or may not be in contact therewith.

  If a photochromic material in which a decoloring reaction due to heat is suppressed is used as the photochromic material, memory property is generated in the photochromic layer. Therefore, the ultraviolet organic electroluminescence device can hold the display if it is driven for a short period until the photochromic layer is colored, and can be held for a long time with less energy by being driven by applying a pulse voltage every certain time. .

  Note that the memory property cannot be generally defined depending on the element configuration, but generally, it can be driven by applying a voltage of 5 V or higher at 25 ° C., and then stopping the voltage application and holding the display for 1 minute or longer. Point to.

  On the other hand, when erasing an image written on the photochromic layer, light of a wavelength corresponding to the absorption of the photochromic material may be irradiated. Specifically, visible light, typically sunlight, fluorescent lamps, etc. What is necessary is just to irradiate room light for a certain time. In addition, a front light used for a spotlight or a liquid crystal display can also be used.

  As the photochromic material used for the photochromic layer, a photochromic material that is colored by being excited by light emitted from the ultraviolet organic electroluminescent element is used. As photochromic materials, the Chemical Society of Japan, “Chemistry of Organic Photochromism” (Quarterly Review of Chemical Chemistry, No. 28, 1996, published by Academic Publishing Center), “Chemical Reviews”, 2000 No. 100, p. 1685-1890, and specific examples thereof include stilbene derivatives, spiropyrans, spirooxazines, diarylethenes, fulgides, cyclophanes, chalcone derivatives, and the like, or mixtures thereof. It is done.

  Of these, spirooxazines, diarylethenes and fulgides are preferred because the photochromic material has high repetitive stability during color development and decoloration due to light and is difficult to cause a decoloration reaction due to heat. Furthermore, from the viewpoint of display characteristics, a material that is excited by light having a maximum emission wavelength of 400 nm or less of the ultraviolet organic electroluminescent device and develops a color from a colorless or light color state is particularly preferable. As these materials, “Chemical Reviews”, 2000, No. 100, p. 1685-1716, and the like, and can be appropriately selected from these.

  Specific examples of diarylethenes include 1,2-bis (2,4-dimethyl-3-thienyl) perfluorocyclopentane, 2,3-bis (2,4,5-trimethyl-3-thienyl) -anhydrous Maleic acid, 2- (1,2-dimethyl-3-indolyl) -3- (2,4,5-trimethyl-3-thienyl) maleic anhydride, 2,3-bis (1,2-dimethyl-3- Indolyl) maleic anhydride, 2,3-bis (1,2-dimethyl-5-methoxy-3-indolyl) maleic anhydride, 2- (1,2-dimethyl-3-indolyl) -3- (2,4 -Dimethyl-5-cyano-3-thienyl) maleic anhydride, 1- (1,2-dimethyl-methoxy-3-indolyl) -2- (2,4-dimethyl-5-cyano-3-thienyl) perfluoro Cyclopentane, 1 2- bis (2-hexyl-3-thienyl) perfluoro cyclopentane dithieno (thiophene) derivatives, and the like.

  In order to form a photochromic layer on the transparent electrode surface of the transparent substrate having a transparent electrode on one side, the photochromic composition is applied or printed on the surface of the transparent electrode and then dried or formed, or The photochromic material is deposited on the transparent electrode surface. Especially, it is preferable to form by the application | coating or printing method from the surface of productivity.

  Examples of the solvent used in the coating or printing method include aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as dichloromethane, chloroform and 1,1,2-trichloroethane, methanol, ethanol and the like. Alcohols, ketones such as cyclohexanone, 1,2-dimethoxyethane, tetrahydrofuran, ethers such as diethylene glycol dimethyl ether, carbonates such as ethylene carbonate and propylene carbonate, esters such as methyl formate and ethyl acetate, acetonitrile, benzonitrile Nitriles such as dimethylformamide, dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, and other aprotic polar solvents can be used. These solvents may be used alone or in combination.

  In addition, a polymer material such as polystyrene, poly (meth) methyl acrylate, polyvinyl acetate, polyvinyl chloride, polyvinyl carbazole, and nylon may be added to the photochromic composition as a binder resin or a dispersion resin. A compound having an active energy ray polymerizable functional group such as a (meth) acryloyl group and a maleimide group can also be added. Moreover, you may add an oligomer and the well-known and usual various additives used for an ink and a coating within the range which does not inhibit the coloring characteristic and aging stability of a photochromic material.

  In order to obtain a high color development state, the photochromic layer preferably contains 10% by mass or more of the photochromic material. Therefore, the binder resin and the dispersion resin are preferably added as appropriate within this range. The photochromic material in the photochromic layer is more preferably contained in an amount of 50% by mass or more.

  When the film thickness of the photochromic layer is such that the absorbance at the time of color development of the photochromic material is 1 or more, a clear display can be obtained. Since the absorption coefficient at the time of color development of the photochromic material varies depending on the photochromic material, the film thickness cannot be specified unconditionally, but usually, when the film thickness of the photochromic layer after drying is in the range of 10 nm to 100 μm, a clear display is obtained. Can be obtained. The photochromic composition is used by appropriately adjusting the non-volatile content concentration so that the film thickness after drying is in the range of 10 nm to 100 μm.

  Examples of the method for applying or printing the photochromic layer on the surface of the electrode include, for example, coating methods such as die coating, (micro) gravure coating, spin coating, applicator method, ink jet printing, planographic printing, gravure printing, screen printing, and the like. The known and commonly used coating methods and printing methods can be applied. There is no restriction | limiting in the method of drying a coating film, For example, what is necessary is just to dry using a hotplate, oven, an infrared furnace, etc.

On the other hand, when a photochromic layer is formed by vapor deposition, it is formed by vacuum vapor deposition from tungsten, molybdenum boat, ceramic crucible, or Knudsen cell under a vacuum higher than 10 ⁻³ Pa using a general-purpose vacuum vapor deposition apparatus. can do. The film thickness may be the same as in the above printing or coating method.

  Hereinafter, the present invention will be described more specifically with reference to examples. In the following examples, “%” is based on mass unless otherwise specified.

<Synthesis Example 1>
(Compound (3); method for producing 1,3,5-tris (9,9′-spirobifluoren-2-yl) benzene)
Mg (0.63 g, 26.8 mmol) was added to a 100 mL three-necked flask and vacuum dried while heating for 30 minutes. Next, 1 mL of 2-bromobiphenyl (4.3 mL, 25 mmol) dissolved in 10 mL of THF (Tetrahydrofuran) was first added under an argon stream to induce the reaction. The reaction solution was refluxed for 3 hours. At this time, Mg completely disappeared and the reaction system turned brown. To this reaction system, fluorenone (5 g, 27.5 mmol) dissolved in 45 mL of THF was added dropwise over 30 minutes, and then refluxed for 17 hours. The reaction system was returned to room temperature, 35-40 mL of an ice-cooled saturated ammonium chloride aqueous solution was added thereto, and the mixture was allowed to stand for 2 hours. The resulting precipitate was filtered off, washed with ether, and dried in vacuo for 1 hour. 50 mL of acetic acid was added to the dried solid and boiled with stirring to completely dissolve the solid, to which 5-6 drops of concentrated hydrochloric acid were added. The solid produced by this operation was separated and recrystallized from a mixed solvent of ethanol / chloroform (volume ratio 1/1) to obtain a flake white solid (compound represented by the chemical formula (a)) (7 .20 g, 91% yield).

（ａ）

(A)

A compound represented by the chemical formula (a) (3.16 g, 10 mmol), aluminum trichloride (AlCl ₃ ) (4.5 g), and carbon disulfide (CS ₂ ) (30 mL) were added to a 100 mL three-necked flask in this order, and ice water Stirring while cooling in a bath, a solution of acetyl chloride (1 mL, 12 mmol) in carbon disulfide (CS ₂ ) (5 mL) was added dropwise over 40 minutes. After dropping, the mixture was stirred for 20 minutes while being cooled in an ice-water bath, then returned to room temperature, stirred for 40 minutes, and refluxed for another 2 hours. The reaction mixture was quenched with a mixture of 2N hydrochloric acid (50 mL) and water (100 mL), extracted with ethyl acetate, and then the organic layer was washed with water, aqueous sodium hydrogen carbonate solution and 30% brine, magnesium sulfate. And dried to obtain a slightly yellow solid. The obtained solid was purified using column chromatography (carrier: silica gel, developing solvent: hexane / ethyl acetate = 10/1), recrystallized from a mixed solvent of chloroform / toluene (1/2), and the target compound ( Compound represented by chemical formula (b)) was obtained (1.8 g, yield 50%).

（ｂ）

(B)

Under a stream of argon, a compound represented by the chemical formula (b) (358 mg, 1.00 mmol), toluene (30 mL) and silicon tetrachloride (SiCl ₄ ) (4.5 mL, 40 mmol) were added to a 100 mL three-necked flask. Ethanol (9 mL, 160 mmol) was added dropwise over time, and then stirred at room temperature for 4 days. Ice water was poured into the reaction solution to stop the reaction, and the precipitated resinous solid was sufficiently washed with water and separated by filtration. The obtained solid was sufficiently washed with chloroform and dichloromethane, and vacuum dried at room temperature to obtain 350 mg of the desired compound (3) as a light yellow powdery solid. Purification was performed by sublimation because the product was insoluble in organic solvents (95 mg after sublimation purification, yield 28%).

（３）

(3)

Analytical data for this compound was as follows:
FTIR-470 plus manufactured by JASCO was used, IR measurement was performed by the KBr tablet method, LA400 manufactured by JEOL Ltd. was used, ¹ H NMR measurement was performed using deuterated chloroform as a measurement solvent, and the compound was confirmed.

Elemental analysis (%): Calcd. _{for C 81 H 48: C,} 95.26; H, 4.74. Found: C, 95.16; H, 4.74.
Differential scanning calorimetry (DSC) measurement: About 5 mg of the compound represented by the chemical formula (3) was weighed as a sample and heated to 550 ° C. in a differential scanning calorimeter (differential scanning calorimeter DSC7 manufactured by PerkinElmer). The melting point (Tm) was 498 ° C. Then, after cooling to room temperature at a rate of 150 ° C./min, the thermal characteristics were subsequently measured at a rate of temperature increase of 10 ° C./min. The glass transition point (Tg) was 237 ° C. In addition, no melting point was observed during the heating process after melting.

Absorption spectrum: Using a vacuum deposition apparatus, a deposited film (amorphous film) having a thickness of 40 nm was formed, and this was measured using a UV-VIS-NIR spectrum photometer UV-3150 manufactured by Shimadzu Corporation. It was shown in 1.

Fluorescence spectrum: Using a vacuum deposition apparatus, a 40 nm thick deposited film (amorphous film) was formed. S300 Single Photon Photomultiplier Detection System) was used to measure the fluorescence spectrum using excitation light with a wavelength of 311 nm. As shown in FIG. 1, it has an emission peak at 392 nm.

<Synthesis Example 2>
(Compound (2); 1,3-bis (9,9′-spirobifluoren-2-yl) benzene production method)
Magnesium (0.3 g, 12 mmol) was added to a 100 mL three-necked flask and vacuum dried while heating for 30 minutes. Next, 5 mL of ethanol was added under an argon stream, and 2-bromobiphenyl (2.4 mL, 4 mmol) was slowly added dropwise thereto (firstly adding 1 mL to induce the reaction, about 10 minutes) Later, the rest was added dropwise over 30 minutes) and then refluxed for 3 hours (magnesium disappeared completely and the reaction system turned brown). 2-Bromofluorenone (1.3 g, 5 mmol) dissolved in 60 mL of ethanol / ether (volume ratio 2/1) mixed solvent was dropped into this reaction system over 30 minutes (a white solid was added when half the amount was added). Production), and refluxed for 17 hours after completion of dropping. The reaction system was returned to room temperature, 20 mL of ice-cooled saturated ammonium chloride (NH ₄ Cl) was added thereto, and the mixture was allowed to stand for 2 hours, and the produced precipitate was separated by filtration. The obtained solid was washed with ether and vacuum dried for 1 hour, and then 25 mL of acetic acid was added to completely dissolve the solid, and 5 to 6 drops of concentrated hydrochloric acid was added thereto for reprecipitation. The solid thus obtained was separated and recrystallized from a mixed solvent of ethanol / chloroform (1: 1) to obtain a flake white solid (compound represented by the chemical formula (c)) (7.20 g, Yield 65%).

（ｃ）

(C)

A compound represented by the chemical formula (c) (0.40 g, 1 mmol) and THF (4 mL) were added to a 100 mL three-necked flask under an argon stream, and the mixture was cooled to −78 ° C. 159M n-butyllithium (n-BULi) (0.75 mL, 1.2 mol) was added dropwise thereto, and then boronic acid (B (OMe) ₃ ) (0.18 mL, 1.5 mmol) was added dropwise to room temperature. Refluxed overnight. The reaction is stopped by adding 2N hydrochloric acid, and after extraction with ethanol, the organic layer is washed with 30% brine, dried over magnesium sulfate, concentrated, and then the target product 2-spirobifluoreneboronic acid (represented by chemical formula (d)). Compound) was obtained as a white solid (0.13 g, 36% yield).

（ｄ）

(D)

In a 100 mL three-necked flask under an argon stream, tetrakistriphenylphosphine palladium (Pd (PPh ₃ ) ₄ ) (0.064 mmol, 74 mg), 1,3-diiodobenzene (0.8 mmol, 264 mg), benzene / carbonic acid Aqueous sodium solution (2M) / ethanol (volume ratio 4/2/1) (350 mL) and the compound represented by the chemical formula (d) (2.4 mmol, 880 mg) were added in this order, and the mixture was stirred at 90 ° C. for 20 hours. The reaction was quenched with a saturated aqueous solution of ammonium chloride (NH ₄ Cl), extracted with dichloromethane, the organic layer was washed with 30% brine, dried over magnesium sulfate, and concentrated. The obtained solid was purified using column chromatography (carrier: silica gel, developing solvent: hexane / dichloromethane = 2/1), recrystallized from a chloroform / ethanol mixed solvent, and the target compound (2) was converted into a white powder. Obtained (306 mg, 53% yield).

（２）
得られた化合物（２）の分析データは以下の通りであった。
ＪＡＳＣＯ社製 ＦＴＩＲ−４７０ ｐｌｕｓを使用し、ＫＢｒ錠剤法によってＩＲ測定し、日本電子株式会社製 ＬＡ４００を使用し、重クロロホルムを測定溶媒に用いて¹Ｈ ＮＭＲ測定して化合物の確認を行った。
元素分析（％）：Ｃａｌｃｄ． ｆｏｒ Ｃ₅₆Ｈ₃₄・０．８Ｈ₂Ｏ： Ｃ， ９３．２５； Ｈ， ４．９７． Ｆｏｕｎｄ： Ｃ， ９３．０９； Ｈ， ４．７９．

(2)
The analytical data of the obtained compound (2) were as follows.
FTIR-470 plus manufactured by JASCO was used, IR measurement was performed by the KBr tablet method, LA400 manufactured by JEOL Ltd. was used, ¹ H NMR measurement was performed using deuterated chloroform as a measurement solvent, and the compound was confirmed.
Elemental analysis (%): Calcd. for C ₅₆ H ₃₄ · 0.8H ₂ O: C, 93.25; H, 4.97. Found: C, 93.09; H, 4.79.

Differential scanning calorimetry (DSC): About 1 mg of the compound (A) is weighed as a sample, and once melted in a differential scanning calorimeter (DSC822 manufactured by METTTLER TOLEDO), it is allowed to reach room temperature at a rate of 30 ° C./min. When cooled, the sample did not crystallize and became amorphous glass. Subsequently, the thermal characteristics were measured at a temperature elevation rate of 10 ° C./min with reference to aluminum.
The glass transition point (Tg) was 183 ° C., the crystallization temperature (Tc) was 264 ° C., and the melting point (Tm) was 356 ° C.

Absorption spectrum: A 40 nm thick deposited film (amorphous film) was formed using a vacuum deposition apparatus, and this was measured using a UV-VIS-NIR spectrum photometer UV-3150 manufactured by Shimadzu Corporation. It was shown to.

Fluorescence spectrum: Using a vacuum deposition apparatus, a 40 nm thick deposited film (amorphous film) was formed. S300 Single Photon Photomultiplier Detection System) was used to measure the fluorescence spectrum using excitation light with a wavelength of 311 nm. As shown in FIG. 2, it has an emission peak at 369 nm.

<Synthesis Example 3>
(Production method of compound (5); 1- (9,9′-spirobifluoren-2-yl) naphthalene))
In a 100 mL three-necked flask under an argon stream, tetrakistriphenylphosphine palladium (Pd (PPh ₃ ) ₄ ) (0.064 mmol, 74 mg), a compound represented by the chemical formula (c) (1 mmol, 395 mg), benzene / carbonic acid Aqueous sodium solution (2M) / ethanol (volume ratio 4/2/1) (350 mL) and 1-naphthalene boronic acid (1.2 mmol, 206 mg) were added in this order, and the mixture was stirred at 90 ° C. for 20 hours. did. The reaction was quenched with a saturated aqueous solution of ammonium chloride (NH ₄ Cl), extracted with dichloromethane, the organic layer was washed with 30% brine, dried over magnesium sulfate, and concentrated. The obtained solid was purified using column chromatography (carrier: silica gel, developing solvent: hexane / dichloromethane = 2/1), recrystallized from a chloroform / ethanol mixed solvent, and the target compound (5) was converted into a white powder. Obtained (255 mg, 56%).

（５）

(5)

Analytical data for this compound was as follows:
FTIR-470 plus manufactured by JASCO was used, IR measurement was performed by the KBr tablet method, LA400 manufactured by JEOL Ltd. was used, ¹ H NMR measurement was performed using deuterated chloroform as a measurement solvent, and the compound was confirmed.
Elemental analysis (%): calcd. for C ₃₅ H ₂₂ : C, 94.99; H, 5.01. Found: C, 94.72; H, 5.07.

Differential scanning calorimetry (DSC): About 1 mg of the compound (5) is weighed as a sample, and once melted in a differential scanning calorimeter (DSC822 manufactured by METTTLER TOLEDO), it is cooled to room temperature at a rate of 50 ° C./min. Although cooled, the sample did not crystallize and became amorphous glassy. Subsequently, the thermal characteristics were measured at a heating rate of 5 ° C./min with reference to aluminum. The glass transition point (Tg) was 99 ° C. and the melting point (Tm) was 240 ° C.

Absorption spectrum: A 40 nm thick deposited film (amorphous film) was formed using a vacuum deposition apparatus, and this was measured using a UV-VIS-NIR spectrum photometer UV-3150 manufactured by Shimadzu Corporation. It was shown to.

Fluorescence spectrum: Using a vacuum deposition apparatus, a 40 nm thick deposited film (amorphous film) was formed. S300 Single Photon Photomultiplier Detection System) was used to measure the fluorescence spectrum using excitation light with a wavelength of 311 nm. As shown in FIG. 3, it has an emission peak at 399 nm.

<Synthesis Example 4>
(Production method of compound (4); 2- (9,9′-spirobifluoren-2-yl) naphthalene))
In a 100 mL three-necked flask under an argon stream, tetrakistriphenylphosphine palladium (Pd (PPh ₃ ) ₄ ) (0.064 mmol, 74 mg), a compound represented by the chemical formula (c) (1 mmol, 395 mg), benzene / carbonic acid Aqueous sodium solution (2M) / ethanol (volume ratio 4/2/1) (350 mL) and 2-naphthalene boronic acid (1.2 mmol, 206 mg) were added in this order, and the mixture was stirred at 90 ° C. for 20 hours. did. The reaction was quenched with a saturated aqueous solution of ammonium chloride (NH ₄ Cl), extracted with dichloromethane, the organic layer was washed with 30% brine, dried over magnesium sulfate, and concentrated. The obtained solid was purified using column chromatography (carrier: silica gel, developing solvent: hexane / dichloromethane = 2/1), recrystallized from a chloroform / ethanol mixed solvent, and then the desired compound (4) was white powder. (286 mg, 63%).

（４）

(4)

Analytical data for this compound was as follows:
FTIR-470 plus manufactured by JASCO was used, IR measurement was performed by the KBr tablet method, LA400 manufactured by JEOL Ltd. was used, ¹ H NMR measurement was performed using deuterated chloroform as a measurement solvent, and the compound was confirmed.

Elemental analysis (%): calcd. for C ₃₅ H ₂₂ .0.3H ₂ O: C, 93.84; H, 5.08. Found: C, 93.74; H, 5.01.

Differential scanning calorimetry (DSC): About 1 mg of the compound (4) as a sample is weighed and once melted in a differential scanning calorimeter (DSC822 manufactured by METTTLER TOLEDO), and then brought to room temperature at a rate of 50 ° C./min. Although cooled, the sample did not crystallize and became amorphous glassy. Subsequently, the thermal characteristics were measured at a heating rate of 5 ° C./min with reference to aluminum. The glass transition point (Tg) was 103 ° C. and the melting point (Tm) was 174 ° C.

Absorption spectrum: A 40 nm thick deposited film (amorphous film) was formed using a vacuum deposition apparatus, and this was measured using a UV-VIS-NIR spectrum photometer UV-3150 manufactured by Shimadzu Corporation. It was shown to.

Fluorescence spectrum: Using a vacuum deposition apparatus, a 40 nm thick deposited film (amorphous film) was formed. S300 Single Photon Photomultiplier Detection System) was used to measure the fluorescence spectrum using excitation light with a wavelength of 311 nm. As shown in FIG. 4, it has an emission peak at 399 nm.

<Synthesis Example 5>
(Method for producing compound (8); 1,4-bis (9,9′-spirobifluoren-2-yl) naphthalene))
Under a stream of argon, tetrakistriphenylphosphine palladium (Pd (PPh3) 4) (0.064 mmol, 74 mg), 1,4-dibromonaphthalene (1,4-Dibromonaphthalene) (0.8 mmol, 100 mg) was added to a 100 mL three-necked flask. ), A benzene / sodium carbonate aqueous solution (2M) / ethanol (volume ratio 4/2/1) (350 mL), and a compound represented by the chemical formula (d) (2.4 mmol, 880 mg) were added in this order, Stir with. The reaction was quenched with a saturated aqueous solution of ammonium chloride (NH ₄ Cl), extracted with dichloromethane, the organic layer was washed with 30% brine, dried over magnesium sulfate, and concentrated. The obtained solid was purified using column chromatography (carrier: silica gel, developing solvent: hexane / dichloromethane = 2/1), recrystallized from a chloroform / ethanol mixed solvent, and the target compound (8) was converted into a white powder. Obtained (244 mg, 42% yield).

（８）

(8)

Analytical data for this compound was as follows:
FTIR-470 plus manufactured by JASCO was used, IR measurement was performed by the KBr tablet method, LA400 manufactured by JEOL Ltd. was used, ¹ H NMR measurement was performed using deuterated chloroform as a measurement solvent, and the compound was confirmed.

Elemental analysis (%): Anal. calcd. for C ₆₀ H ₃₆ · 0.7 H ₂ O: C, 93.64; H, 4.90. Found: C, 93.45; H, 4.87.

<Example 1>

(Organic electroluminescent device using compound (3) in the light emitting layer)
As shown in FIG. 10, after the ITO electrode 1 was formed on the glass substrate, copper phthalocyanine (CuPc) was vacuum deposited on the ITO electrode 1 to form a hole transport layer 2 having a thickness of 15 nm. Subsequently, the compound (3) was vapor-deposited on the hole transport layer 2 as an organic electroluminescent element material to form a 50 nm light-emitting layer 3. Thereafter, 2- (4-Biphenylyl) -5- (p-tert-butylphenyl) -1,3,4-oxadiazole (PBD) was deposited on the light emitting layer 3 to form an electron transport layer 4 having a thickness of 20 nm. An organic electroluminescent device was manufactured by forming LiF 1 nm as a buffer layer and Al 80 nm as a cathode 5 on the electron transport layer 4 by vapor deposition. Seals 6 and 7 were provided at both ends of the organic electroluminescent element.

The organic electroluminescence spectrum of the obtained organic electroluminescence device is shown in FIG. From FIG. 5, the organic electroluminescence device having a light emitting layer using the compound (3) as a material for an organic electroluminescence device emits light in an ultraviolet region having a maximum emission wavelength of 368 nm and a maximum emission wavelength λ _max of 400 nm or less. It turns out that it is an element.

<Example 2>
(Organic electroluminescent device using compound (2) in the light emitting layer)
An organic electroluminescent element was produced in the same manner as in Example 1 except that the compound (2) was used for the light emitting layer.
The organic electroluminescence spectrum of the obtained organic electroluminescence device is shown in FIG.

From FIG. 6, the organic electroluminescence device having the light emitting layer using the compound (2) as a material for the organic electroluminescence device emits light in the ultraviolet region having a maximum emission wavelength of 366 nm and a maximum emission wavelength λ _max of 400 nm or less. It turns out that it is an element.

<Example 3>
(Organic electroluminescent device using compound (5) in the light emitting layer)
An organic electroluminescent element was produced in the same manner as in Example 1 except that the compound (5) was used for the light emitting layer.

The organic electroluminescence spectrum of the produced organic electroluminescence device is shown in FIG.
From FIG. 7, the organic electroluminescence device having a light emitting layer using the compound (5) as a material for an organic electroluminescence device emits light in the ultraviolet region having a maximum emission wavelength of 377 nm and a maximum emission wavelength λ _max of 400 nm or less. It turns out that it is an element.

<Example 4>
(Organic electroluminescent device using compound (4) in the light emitting layer)
An organic electroluminescent element was produced in the same manner as in Example 1 except that the compound (4) was used for the light emitting layer.

The organic electroluminescence spectrum of the obtained organic electroluminescence device is shown in FIG.
From FIG. 8, the organic electroluminescence device having a light emitting layer using the compound (4) as a material for an organic electroluminescence device emits light in the ultraviolet region having a maximum emission wavelength of 361 nm and a maximum emission wavelength λ _max of 400 nm or less. It turns out that it is an element.

<Comparative Example 1>
(Organic electroluminescent device using compound (8) in light emitting layer)
An organic electroluminescent element was produced in the same manner as in Example 1 except that the compound (8) was used for the light emitting layer.

FIG. 9 shows an organic electroluminescence spectrum of the organic electroluminescence device thus produced.
From FIG. 9, it can be seen that the organic electroluminescence device having the light emitting layer using the compound (8) as the material for the organic electroluminescence device has a maximum emission wavelength of 414 nm and no maximum emission wavelength λ _{max in} the ultraviolet region of 400 nm or less.

<Example 5> Example of photochromic element As a photochromic material, 2- (1,2-dimethylindol-3-yl) -2- (2-methyl-1-benzothiophen-3-yl) hexafluorocyclopentene (15 mg) ) And polystyrene (50 mg) having a Mn (number average molecular weight) of 100,000 as a binder are dissolved in toluene (1 mL), and the toluene solution is applied to a glass substrate having a vertical and horizontal length of 20 mm using an applicator. To a thickness of 1 μm to form a photochromic layer made of 2- (1,2-dimethylindol-3-yl) -2- (2-methyl-1-benzothiophen-3-yl) hexafluorocyclopentene did. The photochromic layer was pressure-bonded to the supporting glass substrate side of the organic electroluminescent element obtained in Example 1 to obtain a photochromic display element. FIG. 11 is a cross-sectional view of a photochromic display element, and 8 is a photochromic layer. Other configurations are the same as those in FIG.

  The photochromic display element was applied with a 7V DC voltage for 1 minute using the ITO electrode as an anode, and then the voltage application was stopped. The photochromic layer was colored in blue, and when the sharp cut filter Y-48 was superimposed on the glass substrate on the photochromic layer side, the colored state was maintained for 10 minutes or more under room light.

<Example 6>
2- (1,2-5-methoxydimethylindol-3-yl) -2- (2-methyl-1-benzothiophen-3-yl) hexafluorocyclopentene (15 mg) as photochromic material and Mn as binder Was dissolved in toluene (1 mL), and the toluene solution was applied to a thickness of 1 μm on a glass substrate having a length and width of 20 mm using an applicator, and 2- A photochromic layer made of (1,2-dimethylindol-3-yl) -2- (2-methyl-1-benzothiophen-3-yl) hexafluorocyclopentene was formed. The photochromic layer was pressure-bonded to the supporting glass substrate side of the organic electroluminescent element obtained in Example 1 to obtain a photochromic display element.

  The photochromic display element was applied with a 7V DC voltage with the ITO electrode as the anode for 1 minute, and then the application was stopped. The photochromic layer was colored in blue, and when the sharp cut filter Y-48 was superimposed on the glass substrate on the photochromic layer side, the colored state was maintained for 10 minutes or more under room light.

  The compound of the present invention is useful as a material for an ultraviolet organic electroluminescence device. In addition, the organic electroluminescence device according to the present invention can provide a photochromic display device having a memory property in combination with a photochromic material that absorbs ultraviolet rays and develops color.

It is the absorption spectrum and fluorescence spectrum of the compound (3) synthesize | combined in the synthesis example 1. FIG. It is an absorption spectrum and a fluorescence spectrum of the compound (2) synthesized in Synthesis Example 2. It is the absorption spectrum and fluorescence spectrum of the compound (5) synthesize | combined in the synthesis example 3. FIG. It is the absorption spectrum and fluorescence spectrum of the compound (4) synthesize | combined in the synthesis example 4. It is an organic electroluminescent spectrum of the organic electroluminescent element produced by Example 1 (compound (3)). It is an organic electroluminescent spectrum of the organic electroluminescent element produced by Example 2 (compound (2)). It is an organic electroluminescent spectrum of the organic electroluminescent element produced by Example 3 (compound (5)). It is an organic electroluminescent spectrum of the organic electroluminescent element produced with Example 4 (compound (4)). It is an organic electroluminescent spectrum of the organic electroluminescent element produced by the comparative example 1 (compound (8)). It is sectional drawing which shows an example of the organic electroluminescent element of this invention. It is sectional drawing which shows an example of the photochromic display element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrode 2 Hole transport layer 3 Light emitting layer (comprising the compound of this invention)
4 Electron transport layer 5 Electrode 6 Seal 7 Seal 8 Photochromic layer

Claims (5)

General formula (1)-(7)

(In each formula, Sp is

Represents. However, X < ₁ > -X < ₄ > represents a C1-C8 alkyl group, a halogen atom, or a cyano group each independently, and has the benzene ring or naphthalene ring which General formula (1)-(7) has. The hydrogen atom may be substituted with an alkyl group having 1 to 8 carbon atoms. )
An organic electroluminescent element material containing at least one compound selected from the group consisting of: General formula (2)

(However, Sp means the same structure as in the general formula (1), and the hydrogen atom of the benzene ring may be substituted with an alkyl group having 1 to 8 carbon atoms.)
Or general formula (3)

(However, Sp means the same structure as in the general formula (1), and the hydrogen atom of the benzene ring may be substituted with an alkyl group having 1 to 8 carbon atoms.)
The material for organic electroluminescent elements according to claim 1 represented by: General formula (4)

(However, Sp means the same structure as in the general formula (1), and the hydrogen atom of the naphthalene ring may be substituted with an alkyl group having 1 to 8 carbon atoms).
General formula (6)

(However, Sp means the same structure as in the general formula (1), and the hydrogen atom of the naphthalene ring may be substituted with an alkyl group having 1 to 8 carbon atoms.)
Or general formula (7)

(However, Sp means the same structure as in the general formula (1), and the hydrogen atom of the naphthalene ring may be substituted with an alkyl group having 1 to 8 carbon atoms.)
The material for organic electroluminescent elements according to claim 1 represented by: The organic electroluminescent element which has a light emitting layer which has the material for organic electroluminescent elements of Claim 1 between the anode and cathode which oppose, a hole transport layer, and an electron carrying layer. The photochromic display element which uses the light which the organic electroluminescent element of Claim 4 light-emits as excitation light.

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