JP6370030B2 - Compound for organic electroluminescence device and organic electroluminescence device using the same - Google Patents

Description

  The present invention relates to a compound for an organic electroluminescent device and an organic electroluminescent device using the same.

  Organic electroluminescence devices have been actively studied for practical use in next-generation thin flat displays and lighting. Conventionally, organic electroluminescent elements have been expected to have lower power consumption than thin flat displays such as liquid crystals. However, it is difficult to say that the characteristics can be fully exploited at present. Improvements are being actively studied toward lower power consumption. In the development of organic electroluminescent lighting, low power consumption is strongly demanded.

  An electroluminescent element used in a display device such as an organic electroluminescent display includes, for example, an organic layer such as a luminescent layer containing a luminescent organic material between a hole injection electrode (anode) and an electron injection electrode (cathode). Is. By applying an electric field from the electrode to the light emitting layer, the light emitting organic material is excited and emits light.

  The light emission principle of this organic electroluminescence device is generally considered as follows. In other words, first, holes injected from the anode and electrons injected from the cathode are recombined in the light emitting layer, thereby generating excitons of the light emitting organic material. Then, when the exciton is deactivated, energy is released as a light (fluorescence, phosphorescence) component. This is believed to cause light emission.

  As one of the methods for suppressing the driving voltage of such an organic electroluminescent device and improving the light emission efficiency, a hole transport layer, which is different from the light emitting layer, is provided between the anode and the light emitting layer and between the cathode and the light emitting layer. And a method of providing an electron transport layer. Thereby, holes and electrons can be smoothly injected from the anode and the cathode into the light emitting layer. Currently, a hole injection layer and an electron injection layer are inserted between the anode and the hole transport layer, and the cathode and the electron transport layer, respectively, in order to achieve further lower power consumption, higher efficiency light emission, and longer life. This structure has become mainstream.

  Various aromatic amine derivatives are known as materials for the hole injecting and transporting layer. As a compound having dibenzo [b, e] [1,4] dioxin in the central skeleton of the diamine structure, Patent Document 1 The compound of -2 is mentioned.

Japanese Patent No. 4976292 International Publication No. 2005/075451

  However, when a compound having dibenzo [b, e] [1,4] dioxin in the central skeleton of these diamine structures is used as a constituent material, the driving voltage of the organic electroluminescence device cannot be sufficiently reduced. The power consumption cannot be sufficiently suppressed.

  The present invention has been made in view of the above circumstances, and when used as a constituent material of an organic electroluminescent element, an organic electric field capable of sufficiently reducing a driving voltage and suppressing power consumption. It aims at providing the compound for light emitting elements, and the organic electroluminescent element using this compound.

  As a result of intensive studies, the present inventors have found that the above problem can be solved by using a compound represented by the following general formula (1) as a material for an organic electroluminescence device. Since the compound represented by the following general formula (1) of the present invention exhibits high hole transport characteristics, when used as a constituent material of an organic electroluminescence device, the driving voltage can be greatly reduced. In addition, since the compound represented by the following general formula (1) exhibits high hole injection characteristics from the anode, when it is used as a hole injection layer of an organic electroluminescence device, a higher driving voltage reduction effect can be obtained. Show.

  The compound for organic electroluminescent elements of the present invention is represented by the following general formula (1).

[Wherein R ₁ represents a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. An alkoxy group which may have, an aryloxy group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a plurality of R ₁ bonded together. The resulting divalent group is shown. a is an integer of 0 to 4, and b is an integer of 1 to 3. At least one of Ar _{1 to} Ar ₄ is represented by the following general formula (2) or (3).

(In the formula, R ₂ and R ₃ are each independently selected from the same groups as R ₁ in the general formula (1). L ₁ is an aromatic group that may have a single bond or a substituent. A divalent group containing a hydrocarbon skeleton is represented, c is an integer of 0 to 4, and d is an integer of 0 to 3.)

(In the formula, R ₄ and R ₅ are each independently selected from the same group as R ₁ in the above general formula (1). L ₂ is the same group as L ₁ in the above general formula (2). E is an integer of 0-6, and f is an integer of 0-3.) In General Formula (1), Ar _{1 to} Ar ₄ that are not General Formula (2) are respectively Independently, an aryl group which may have a substituent or an aromatic heterocyclic group which may have a substituent is shown. ]

  According to such a compound for an organic electroluminescent element, when used as a constituent material of the organic electroluminescent element, the driving voltage of the organic electroluminescent element can be sufficiently reduced, and power consumption can be suppressed. The reason why such an effect can be obtained by the compound for organic electroluminescence device of the present invention is not necessarily clear, but the present inventors consider as follows.

  A compound having a dibenzo [b, e] [1,4] dioxin skeleton or a benzodibenzo [b, e] [1,4] dioxin skeleton at the end of the diamine structure of the present invention has a dibenzo [B, e] [1, 4] Compared with a compound having dioxin, since it exhibits high hole transport properties, when used as a hole injection layer, a hole transport layer and a light emitting layer material of an organic electroluminescence device, It is possible to reduce the driving voltage.

  Moreover, when the compound for organic electroluminescent elements of the present invention is used as a hole injection layer material, it exhibits a particularly high voltage reduction effect and can form a highly uniform light emitting surface. That is, the compound for organic electroluminescence device of the present invention has a strong interaction with the anode and exhibits a high hole injection characteristic and a driving voltage to form a uniform thin film with high adhesion to the anode. It is considered possible. The compound for an organic electroluminescence device of the present invention has a dibenzo [b, e] [1,4] dioxin skeleton or benzodibenzo [b, e] [1,1 having a high polarity and a large steric hindrance at the terminal portion of the diamine structure. 4] It has a dioxin skeleton. We believe that a uniform thin film with high adhesion to the anode can be formed by suppressing the crystallization associated with the interaction between the polar group having an oxygen atom at the end and the anode and the intermolecular interaction due to steric hindrance. . Since the dibenzo [b, e] [1,4] dioxin skeleton or the benzodibenzo [b, e] [1,4] dioxin skeleton is provided not at the central part of the diamine structure but at the terminal part, the above effect can be obtained. I believe.

  Further, the compound represented by the general formula (1) having two or more substituents represented by the general formula (2) or (3) is represented by the general formula (2) or (3). The voltage lowering effect is higher than that of a compound having one substituent. We believe that a higher voltage-lowering effect can be obtained because of the high hole transport characteristics and the high number of polar groups that interact with the anode, and the high hole injection characteristics due to improved adhesion to the anode.

  Further, the present invention is an organic electroluminescent device comprising one or more organic layers between two electrodes arranged to face each other, and at least one of the organic layers is the above-mentioned organic electric field. Provided is an organic electroluminescent device comprising a compound for a light emitting device. According to this organic electroluminescent element, since the organic electroluminescent element compound of the present invention is included, the driving voltage can be sufficiently suppressed.

  According to the present invention, when used as a constituent material of an organic electroluminescence device, the driving voltage can be sufficiently lowered and the power consumption can be suppressed, and the compound for organic electroluminescence device and this compound are used. An organic electroluminescent element can be provided.

It is a schematic cross section which shows the organic electroluminescent element which concerns on 1st Embodiment. It is a schematic cross section which shows the organic electroluminescent element which concerns on 2nd Embodiment. It is a figure which shows the infrared absorption spectrum of the compound (11) of the synthesis example 1. 1 is a diagram showing a ¹ HNMR spectrum of a compound (11) of Synthesis Example 1. FIG. It is a figure which shows the ¹³ CNMR spectrum of the compound (11) of the synthesis example 1. It is a figure which shows the infrared absorption spectrum of the compound (12) of the synthesis example 2. ¹ is a diagram showing a ¹ HNMR spectrum of a compound (12) of Synthesis Example 2. FIG. It is a figure which shows the ¹³ CNMR spectrum of the compound (12) of the synthesis example 2. It is a figure which shows the infrared absorption spectrum of the compound (13) of the synthesis example 3. It shows The ¹ HNMR spectrum of the compound of Synthesis Example 3 (13). It is a figure which shows the ¹³ CNMR spectrum of the compound (13) of the synthesis example 3. It is a figure which shows the infrared absorption spectrum of the compound (14) of the synthesis example 4. It shows The ¹ HNMR spectrum of the compound of Synthesis Example 4 (14). It is a figure which shows the ¹³ CNMR spectrum of the compound (14) of the synthesis example 4.

  Less than. The preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

(Compound for organic electroluminescence device)
The compound for organic electroluminescent elements according to a preferred embodiment of the present invention is a diamine compound having a specific substituent represented by the general formula (1).

In the general formula (1), _{R n} groups (n = 1 to 5) may be an alkyl group which may have a substituent. The alkyl group moiety may be linear or branched, and the carbon number thereof is preferably 1 to 12, more preferably 1 to 6, and still more preferably 1 to 4. Suitable alkyl groups include methyl, ethyl, propyl, and butyl groups, with methyl being particularly preferred. These alkyl groups may be further substituted with a substituent such as a methoxy group or an ethoxy group, but an alkyl group having no substituent is also suitable.

The R _n group (n = 1 to 5) in the general formula (1) may also be an aryl group which may have a substituent. Specific examples of the aryl group moiety include a phenyl group, a biphenylyl group, a terphenylyl group, a naphthyl group, a phenanthryl group, an anthranyl group, a pyrenyl group, and a fluorenyl group. In more detail, the following chemical formula (i-1) The substituent represented by-(i-19) is mentioned. These groups may be further substituted with a substituent such as a methyl group, an ethyl group, a methoxy group, or a cyclohexyl group.

The R _n group (n = 1 to 5) in the general formula (1) may also be an aralkyl group which may have a substituent. Specific examples of the aralkyl group moiety include a benzyl group and a naphthylmethyl group. These groups may be further substituted with a substituent such as a methyl group, an ethyl group, a methoxy group, or a cyclohexyl group.

The R _n group (n = 1 to 5) in the general formula (1) may also be an alkoxy group which may have a substituent. Specific examples of the alkoxy group moiety include a methoxy group, an ethoxy group, a propyloxy group, and a tert-butoxy group. These groups may be further substituted with a substituent such as a methoxy group or an ethoxy group, but an alkoxy group having no substituent is also suitable.

The R _n group (n = 1 to 5) in the general formula (1) may also be an aryloxy group which may have a substituent. Specific examples of the aryloxy group moiety include a phenoxy group and a naphthyloxy group. These groups may be further substituted with a substituent such as a methyl group, an ethyl group, a methoxy group, or a cyclohexyl group.

The R _n group (n = 1 to 5) in the general formula (1) may also be an aromatic heterocyclic group which may have a substituent. Specific examples of the aromatic heterocyclic group moiety include a pyridyl group, a pyrimidinyl group, a triazinyl group, a furanyl group, a thienyl group, and an indolyl group. More specifically, the following chemical formulas (ii-1) to (ii) Group represented by -16). These groups may be further substituted with a substituent such as a methyl group, an ethyl group, a methoxy group, a cyclohexyl group, or a pyridyl group.

The R _n group (n = 1 to 5) in the general formula (1) may also be a divalent group formed by bonding a plurality of R _n to each other. That is, a plurality of R ₁ may be bonded to each other to form a divalent group, and the same applies to R _{2 to} R ₇ . Specific examples thereof include groups represented by the following chemical formulas (iii-1) to (iii-3). These groups may be further substituted with a substituent such as a methyl group, an ethyl group, a methoxy group, a cyclohexyl group, a phenyl group, a biphenylyl group, or a naphthyl group.

The R _n groups of the general formula (1) (n = 1~5) , a hydrogen atom, an optionally substituted aryl group, or a divalent to R _n which there are a plurality occurs bonded to each other And a divalent group formed by bonding a plurality of R _n represented by the chemical formula (iii-1) to each other is more preferable. preferable. Among R _n groups (n = 1 to 5), R ₁ , R ₃ and R ₅ are preferably a hydrogen atom or an aryl group which may have a substituent, and have a hydrogen atom or a substituent. An optionally substituted phenyl group is more preferred. R ₂ and R ₄ are preferably a hydrogen atom, an aryl group which may have a substituent, or a divalent group formed by bonding a plurality of R _n to each other. A phenyl group which may have or a divalent group formed by bonding a plurality of R _n (n = 2, 4) represented by the chemical formula (iii-1) to each other is more preferable.

In General Formula (1), L ₁ and L ₂ may each independently be a divalent group including an aromatic hydrocarbon skeleton that may have a substituent. Specific examples of the divalent group containing an aromatic hydrocarbon skeleton include a phenylene group, a biphenylene group, a naphthylene group, an anthrylene group, a pyrenylene group, a phenanthrenylene group, and a fluorenylene group. Examples include groups represented by the following chemical formulas (iv-1) to (iv-23) (the two bonds in these groups are each bonded to the nitrogen atom of the amino group in the general formula (1)). It may be bonded to the dibenzo [b, e] dioxin ring in the general formula (2) or the benzodibenzo [b, e] dioxin ring in the general formula (3). The same applies to the groups having the above.) These groups may be further substituted with a substituent such as a methyl group, an ethyl group, a methoxy group, a cyclohexyl group, or a phenyl group.

L ₁ and L _{2 in} the general formula (1) are each independently preferably a single bond or a divalent group containing an aromatic hydrocarbon skeleton, such as a single bond, a phenylene group, a biphenylene group, a naphthylene group, a pyrenylene group, A fluorenylene group is more preferable, and a single bond and a phenylene group are more preferable.

In General Formula (1), Ar _{1 to} Ar ₄ which are not General Formula (2) are each independently an aryl group which may have a substituent or an aromatic heterocycle which may have a substituent. A cyclic group is preferable, and an aryl group which may have a substituent is more preferable.

In General Formula (1), at least one of Ar _{1 to} Ar ₄ represents a group represented by General Formula (2) or (3), but two or more of Ar _{1 to} Ar ₄ are represented by General Formula ( It is preferable that it is group represented by 2) or (3).

  The compound represented by the general formula (1) of the present embodiment is preferably b = 2 in the general formula (1).

  The compound represented by the general formula (1) of the present embodiment is a material for an organic electroluminescence device, a hole injection material for an organic electroluminescence device, a hole transport material for an organic electroluminescence device, or a light emitting layer for an organic electroluminescence device. A material is preferred.

  The organic electroluminescent element of this embodiment is an organic electroluminescent element comprising one or more organic layers between two electrodes arranged opposite to each other, and at least one of the organic layers is a main layer. It is preferable that the compound represented by the general formula (1) of the embodiment is contained alone or as a component of the mixture. Furthermore, in the organic electroluminescent element of this embodiment, it is preferable that the compound represented by the general formula (1) of this embodiment is contained in the hole injection layer, the hole transport layer, or the light emitting layer.

(Specific examples of compounds for organic electroluminescence devices)
As a suitable example of the compound for organic electroluminescent elements of this embodiment, following formula (I-1)-(I-18), (II-1)-(II-18), (III-1)-( III-11), (IV-1) to (IV-12), (V-1) to (V-18), (VI-1) to (VI-18), (VII-1) to (VII-) 12) and a compound represented by (VIII-1).

(Method for producing compound for organic electroluminescence device)
The manufacturing method of the compound for organic electroluminescent elements of this embodiment is demonstrated taking the following compound (G), (K), (P) as an example.

  The following compound (G) can be produced as follows.

Compound (C) is obtained by reacting the following compounds (A) and (B) in the presence of potassium carbonate. Compound (C) is reduced using tin chloride to obtain compound (D). Next, Ar ₁ -X is allowed to act on compound (D) in the presence of a palladium catalyst to obtain compound (E). Finally, compound (G) is obtained by reacting compound (E) with compound (F) in the presence of a palladium catalyst.

[Wherein, R ₁ , R ₂ , R ₃ , Ar ₁ are each independently the same group as R ₁ , R ₂ , R ₃ , Ar ₁ in the general formulas (1), (2), (3) B, c and d are selected from among b, c and d in the general formulas (1), (2) and (3). X represents a leaving group (for example, bromine atom, iodine atom, trifluoromethanesulfonyloxy group, etc.). ]

  The following compound (K) can be produced as follows.

  Compound (K) is obtained by reacting the following compounds (H) and (I) in the presence of copper iodide. Next, compound (K) is obtained by allowing compound (E) to act on compound (K) in the presence of a palladium catalyst.

(In the formula, R ₁ , R ₂ , R ₃ , Ar ₁ , Ar ₂ , Ar ₃ are each independently R ₁ , R ₂ , R ₃ , (Selected from the same group as Ar ₁ , Ar ₂ , Ar _3, and b, c, d are selected from b, c, d in the general formulas (1), (2), (3)).

  The following compound (P) can be produced as follows.

The following compound (D) is brominated to obtain compound (L). Compound (N) is obtained by reacting compound (L) and (M) in the presence of a palladium catalyst. Next, Ar ₁ —NH ₂ is allowed to act on Compound (N) in the presence of a palladium catalyst to obtain Compound (O). Finally, compound (P) is obtained by reacting compound (O) with (J) in the presence of a palladium catalyst.

(In the formula, R ₁ , R ₂ , R ₃ , Ar ₁ , Ar ₂ , Ar ₃ are each independently R ₁ , R ₂ , R ₃ , (Selected from the same group as Ar ₁ , Ar ₂ , Ar _3, and b, c, d are selected from b, c, d in the general formulas (1), (2), (3)).

(Organic electroluminescence device)
FIG. 1 is a schematic cross-sectional view showing a first embodiment of an organic electroluminescent element according to the present invention. An organic electroluminescent element 200 shown in FIG. 1 includes a hole injection layer 14, a hole transport layer 11, a light emitting layer 10, and two electrodes (first electrode 1 and second electrode 2) arranged to face each other. In addition, the electron injection / transport layer 13 is held. The hole injection layer 14, the hole transport layer 11, the light emitting layer 10, and the electron injection transport layer 13 are all organic layers, and are stacked in this order from the first electrode 1 side. The electron injecting and transporting layer 13 can be an inorganic layer (metal layer, metal compound layer, etc.).

  FIG. 2 is a schematic cross-sectional view showing a second embodiment of the organic electroluminescent element according to the present invention. The organic electroluminescent element 100 shown in FIG. 2 has a structure in which a light emitting layer 10 is held by two electrodes (first electrode 1 and second electrode 2) arranged to face each other (hereinafter referred to as “the first electrode 1 and second electrode 2”). The same).

  In the first and second embodiments, the first electrode 1 is formed on the substrate 4, but the stacking order from the substrate 4 side may be reversed. That is, in the case of the organic electroluminescence device of the second embodiment, from the substrate 4 side, the second electrode 2, the electron injection transport layer 13, the light emitting layer 10, the hole transport layer 11, the hole injection layer 14, and the first electrode. They may be laminated in the order of 1.

  Moreover, the compound for organic electroluminescent elements of this embodiment may be contained in any of the layers described above, but is desirably contained in the hole injection layer, the hole transport layer, and the light emitting layer.

  In the above-described embodiment, the first electrode 1 and the second electrode 2 function as a hole injection electrode (anode) and an electron injection electrode (cathode), respectively. Then, holes are injected from the second electrode 2 and electrons are injected from the second electrode 2. Based on these recombination, the compound for an organic electroluminescent element in the light emitting layer emits light.

  Moreover, all suitable thickness of the light emitting layer 10, the electron injection transport layer 13, the hole injection layer 14, and the hole transport layer 11 is 1-200 nm.

(substrate)
The substrate 4 can be used without particular limitation as long as it is provided in a conventional organic electroluminescence device, and is an amorphous substrate such as glass or quartz, Si, GaAs, ZnSe, ZnS, GaP. A crystal substrate such as InP or a metal substrate such as Mo, Al, Pt, Ir, Au, Pd, or SUS can be used. Further, a thin film made of a crystalline or amorphous ceramic, metal, organic substance or the like formed on a predetermined substrate may be used.

  When the substrate 4 side is the light extraction side, it is preferable to use a transparent substrate such as glass or quartz as the substrate 4, and it is particularly preferable to use an inexpensive glass transparent substrate. The transparent substrate may be provided with a color filter film, a color conversion film containing a fluorescent material, a dielectric reflection film, or the like for adjusting the emission color.

(First electrode)
The first electrode 1 functions as a hole injection electrode (anode). Therefore, the material of the first electrode 1 can be used without particular limitation as long as the material of the conventional organic electroluminescent element is provided, but the first electrode 1 can be used efficiently and uniformly. A material capable of applying an electric field to is preferable.

  Further, when the substrate 4 side is the light extraction side, the transmittance at a wavelength of 400 nm to 700 nm, which is the emission wavelength region of the organic electroluminescent element, in particular, the transmittance of the first electrode 1 at the wavelength of each RGB color is 50%. Preferably, it is 80% or more, more preferably 90% or more. When the transmittance of the first electrode 1 is less than 50%, the light emission from the light emitting layer 10 is attenuated, and the luminance necessary for image display cannot be obtained.

The 1st electrode 1 with high light transmittance can be comprised using the transparent conductive film comprised with various oxides. As such a material, indium oxide (In ₂ O ₃ ), tin oxide (SnO ₂ ), zinc oxide (ZnO), tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), and the like are preferable. It is particularly preferable in that a thin film having a uniform in-plane specific resistance can be easily obtained.

  The film thickness of the first electrode 1 is preferably determined in consideration of the above-described light transmittance. For example, when using an oxide transparent electrode, the film thickness is preferably 10 to 500 nm, more preferably 30 to 300 nm. When the film thickness of the first electrode 1 exceeds 500 nm, the light transmittance becomes insufficient, and the first electrode 1 may peel off from the substrate 4 in some cases. Moreover, although the light transmittance improves as the film thickness decreases, when the film thickness is less than 10 nm, the resistivity tends to increase and the drive voltage of the organic electroluminescent element tends to increase.

(Second electrode)
The second electrode 2 functions as an electron injection electrode (cathode). The material of the second electrode 2 can be used without particular limitation as long as it is provided in a conventional organic electroluminescent element, and examples thereof include metal materials, organometallic complexes, and metal compounds. In order to efficiently and reliably inject electrons into the light emitting layer 10, it is preferable to use a material having a relatively low work function, and it may be transparent.

  Specific examples of the metal material constituting the second electrode 2 include alkali metals such as Li, Na, K or Cs, alkaline earth metals such as Mg, Ca, Sr or Ba, or Al (aluminum). . Alternatively, a metal having properties similar to those of an alkali metal or alkaline earth metal such as La, Ce, Sn, Zn, or Zr can be used. Furthermore, oxides or halides of the above metal materials can also be used. Further, it may be a mixture or alloy containing the above materials, and a plurality of these may be laminated.

  The film thickness of the second electrode 2 only needs to be such that electrons can be uniformly injected, and may be 0.1 nm or more.

  An auxiliary electrode may be provided on the second electrode 2. Thereby, the electron injection efficiency to the light emitting layer 10 etc. can be improved, and the penetration | invasion of the water | moisture content or the organic solvent to the light emitting layer 10 or the electron injection layer 13 can be prevented. As a material for the auxiliary electrode, a general metal can be used because there is no restriction on work function and charge injection capability. However, it is desirable to use a metal having high conductivity and easy handling. In particular, when the second electrode 2 includes an organic material, it is desirable to select appropriately according to the type and adhesion of the organic material.

  Examples of the material used for the auxiliary electrode include Al, Ag, In, Ti, Cu, Au, Mo, W, Pt, Pd, and Ni. Among them, by using a low-resistance metal such as Al and Ag. Electron injection efficiency can be further increased. Further, by using a metal compound such as TiN, higher sealing properties can be obtained. These materials may be used alone or in combination of two or more. Moreover, when using 2 or more types of metals, you may use as an alloy. Such an auxiliary electrode can be formed by, for example, a vacuum deposition method or the like.

(Hole injection layer)
As a material for the hole injection layer 14, it is preferable to use the above-described compound for organic electroluminescence device of the present embodiment, that is, the compound (1). An organic electroluminescent device including the hole injection layer 14 containing such a material can sufficiently suppress a driving voltage and reduce power consumption as compared with a conventional organic electroluminescent device.

  The hole injection layer 14 may use the compound (1) alone as a constituent material, contains the compound (1) as a main component material, and is further used as a material for a conventional hole injection layer. You may contain 1 type, or 2 or more types. Examples of such materials include arylamine derivatives, phthalocyanines, polyaniline / organic acids, polythiophene / polymer acids, and the like. Further, the hole injection layer 14 may be heat-treated at a temperature higher than the glass transition temperature of the constituent material.

  The hole injection layer 14 may have a laminated structure of the compound (1) and another material.

(Hall transport layer)
As a material for the hole transport layer 11, it is preferable to use the above-described compound for organic electroluminescence device of the present invention, that is, the compound (1). An organic electroluminescent device including the hole transport layer 11 containing such a material can sufficiently suppress a driving voltage and reduce power consumption as compared with a conventional organic electroluminescent device.

  The hole transport layer 11 may use the compound (1) alone as a constituent material, contains the compound (1) as a main component material, and is further used as a material for a conventional hole transport layer. You may contain 1 type, or 2 or more types. Examples of such materials include arylamine derivatives, triphenyldiamine derivatives, pyrazoline derivatives, stilbene derivatives, and the like as hole transporting low molecular weight materials. Also, hole transporting polymer materials include polyvinyl carbazole (PVK), polyethylenedioxythiophene (PEDOT), polyethylenedioxythiophene / polystyrene sulfonic acid copolymer (PEDOT / PSS), polyaniline / polystyrene sulfonic acid copolymer. (Pani / PSS) and the like.

  The hole transport layer 11 may have a laminated structure of the compound (1) and another material.

  The hole injection layer and the hole transport layer may be formed as a hole injection transport layer using the same material.

(Light emitting layer)
As a material for the light emitting layer 10, it is preferable to use the above-described compound for organic electroluminescence device of the present invention, that is, the compound (1). An organic electroluminescent element including the light emitting layer 10 containing such a material can sufficiently suppress a driving voltage and can reduce power consumption as compared with a conventional organic electroluminescent element.

  The light emitting layer 10 may contain the compound (1) alone as a constituent material, contains the compound (1), and further contains one or more kinds of materials used as the material of the conventional light emitting layer. You may do it. Such a material is not particularly limited as long as it is an organic compound that generates excitons by recombination of electrons and holes, and emits light when the excitons release energy and return to the ground state. For example, organometallic complex compounds such as aluminum complexes, beryllium complexes, zinc complexes, iridium complexes, or rare earth metal complexes, anthracene, naphthacene, benzofluoranthene, naphthofluoranthene, styrylamine, or tetraaryl Diamine or derivatives thereof, low molecular organic compounds such as perylene, quinacdrine, coumarin, DCM or DCJTB, or π-conjugated polymers such as polyacetylene derivatives, polyphenylene vinylene derivatives, polyfluorene derivatives or polythiophene derivatives, High molecular organic compounds such as non-π-conjugated side chain polymers or main chain polymers such as dye compounds, polystyrene derivatives, polysilane derivatives, polyacrylate derivatives or polymethacrylate derivatives be able to.

  The light emitting layer 10 may have a laminated structure of the compound (1) and another material.

(Electron injection transport layer)
The material of the electron injection / transport layer 13 is not particularly limited as long as it is provided in a conventional organic electroluminescence device, and any electron transport material, low molecular material or polymer material, can be used. Can also be used. Examples of the electron transporting low molecular weight material include oxadiazole derivatives, imidazopyridine derivatives, anthraquinodimethane and its derivatives, benzoquinone and its derivatives, naphthoquinone and its derivatives, anthraquinone and its derivatives, tetracyanoanthraquinodimethane and Examples thereof include fluorene and derivatives thereof, diphenyldicyanoethylene and derivatives thereof, phenanthroline and derivatives thereof, and metal complexes having these compounds as ligands. Examples of the electron transporting polymer material include polyquinoxaline and polyquinoline. As the material for the electron injecting and transporting layer 13, one kind may be used alone, or two or more kinds may be used in combination.

  The organic electroluminescence device according to this embodiment can be produced by a known method except that the hole injection layer 14, the hole transport layer 11 and the light emitting layer 10 contain the compound for organic electroluminescence device of the present invention. As a method for forming each organic layer including the hole transport layer 14, the hole transport layer 11, and the light emitting layer 10, a vacuum vapor deposition method, an ionization vapor deposition method, a coating method, or the like, depending on the material constituting the organic layer. And can be selected as appropriate.

  Specific examples of the coating method include a method in which a material used for the organic layer is dissolved in an organic solvent, and then applied by a conventionally known method such as a spin coating method, and the solvent is removed from the coating solution by vacuum drying or the like. It is done. Examples of the solvent used in this coating method include aromatic hydrocarbon solvents such as toluene.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  Hereinafter, the contents of the present invention will be described more specifically with reference to examples and comparative examples. In addition, this invention is not limited to the following Example.

<Synthesis Example 1>
The following compound (11) was synthesized by the following method. The reaction formula is shown below.

(Synthesis of 2-nitrodibenzo [b, e] [1,4] dioxin (1-1))
Under an argon stream, 3.30 g (30.0 mmol) of catechol, 4.77 g (30.0 mmol) of 3,4-difluoronitrobenzene, and 8.29 g (60.0 mmol) of potassium carbonate were added to 35 ml of dehydrated toluene and dehydrated N, N′— The suspension was suspended in a mixed solution of 140 ml of dimethylformamide and stirred at 100 ° C. for 20 hours. The reaction solution was cooled to room temperature and then added to 300 ml of water, and the precipitated solid was filtered and washed with methanol. The obtained solid was dried under reduced pressure to obtain the desired 2-nitrodibenzo [b, e] [1,4] dioxin (1-1) yellow powder (yield 4.28 g, yield 62%).

(Synthesis of 2-aminodibenzo [b, e] [1,4] dioxin (1-2))
2.28 g (18.7 mmol) of 2-nitrodibenzo [b, e] [1,4] dioxin (1-1) synthesized by the above reaction was dissolved in 100 ml of tetrahydrofuran. Next, 50 ml of concentrated hydrochloric acid containing 16.92 g (75.0 mmol) of tin chloride dihydrate was slowly added and stirred at room temperature for 3 hours. The precipitated solid was filtered and suspended in 200 ml of an aqueous sodium hydroxide solution, and the organic matter was extracted with chloroform. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography, and the desired 2-aminodibenzo [b, e] [1,4] dioxin (1-2) white powder (yield 2.94 g, 79%) Got.

(Synthesis of 2- (4-biphenylylamino) dibenzo [b, e] [1,4] dioxin (1-3))
2.94 g (14.8 mmol) of 2-aminodibenzo [b, e] [1,4] dioxin (1-2) synthesized by the above reaction under an argon stream, 3.50 g (15.0 mmol) of 4-bromobiphenyl ), 0.092 g (0.10 mmol) of tris (dibenzylideneacetone) dipalladium (0) and 2.16 g (22.5 mmol) of sodium tert-butoxide were suspended in 110 ml of dehydrated toluene. Next, 0.20 ml of a toluene solution containing 0.20 mmol of tri (tert-butyl) phosphine was added, and the mixture was stirred at 100 ° C. for 22 hours. After cooling to room temperature, 100 ml of water was added to the reaction solution and extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography and recrystallized from dichloromethane-methanol to obtain the desired 2- (4-biphenylylamino) dibenzo [b, e] [1,4] dioxin (1-3). Of white powder (yield 4.37 g, yield 85%).

(Synthesis of Compound (11))
1.93 g (5.5 mmol) of 2- (4-biphenylylamino) dibenzo [b, e] [1,4] dioxin (1-3) synthesized by the above reaction under an argon stream, 4,4′- Dibromobiphenyl 0.78 g (2.5 mmol), tris (dibenzylideneacetone) dipalladium (0) 0.046 g (0.05 mmol), sodium tert-butoxide 0.72 g (7.5 mmol) were suspended in dehydrated toluene 120 ml. I let you. Next, 0.12 ml of a toluene solution containing 0.12 mmol of tri (tert-butyl) phosphine was added, and the mixture was stirred at 100 ° C. for 20 hours. After cooling to room temperature, 100 ml of water was added to the reaction solution and extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The resulting crude product was purified by column chromatography and recrystallized from dichloromethane-methanol to obtain the target compound (11) as a white powder (yield 2.00 g, yield 96%). Furthermore, sublimation purification was performed to obtain a product having a purity of 99.9% (purity confirmed by high performance liquid chromatography (HPLC)).

When the obtained compound was subjected to mass spectrometry, a peak was confirmed at m / z = 853 (M ⁺ ). Moreover, when this compound was analyzed using the infrared absorption spectroscopy (IR) method, IR spectrum shown in FIG. 3 was obtained. Furthermore, it was analyzed using the compound ¹ H- nuclear magnetic resonance ⁽¹ H-NMR) method, ¹ H-NMR spectrum shown in Figure 4 is ^obtained, 13 C-nuclear magnetic resonance ⁽¹ H-NMR) When analyzed by the method, the ¹³ C-NMR spectrum shown in FIG. 5 was obtained. Thus, it was confirmed that the compound obtained in Synthesis Example 1 was the compound (11).

<Synthesis Example 2>
The following compound (12) was synthesized by the following method. The reaction formula is shown below.

(Synthesis of N, N-bis (4-biphenylyl) -4′-bromobiphenyl-4-yl-amine (1-4))
Under an argon stream, 3.21 g (10.0 mmol) of bis (4-biphenylyl) amine, 3.77 g (10.5 mmol) of 4-bromo-4′-iodobiphenyl, 0.29 g (1.5 mmol) of copper iodide, 0.27 g (1.5 mmol) of 1,10-phenanthroline and 1.68 g (15.0 mmol) of potassium tert-butoxide were suspended in 200 ml of dehydrated toluene and stirred at 100 ° C. for 48 hours. After cooling to room temperature, 200 ml of water was added to the reaction solution and extracted with chloroform. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography and recrystallized from dichloromethane-methanol to obtain the desired N, N-bis (4-biphenylyl) -4′-bromobiphenyl-4-yl-amine (1-4 ) White powder (yield 4.92 g, yield 82%).

(Synthesis of Compound (12))
1.50 g (2.5 mmol) of N, N-bis (4-biphenylyl) -4′-bromobiphenyl-4-yl-amine (1-4) synthesized by the above reaction under an argon stream, 2- (4 -Biphenylylamino) dibenzo [b, e] [1,4] dioxin (1-3) 0.92 g (2.6 mmol), tris (dibenzylideneacetone) dipalladium (0) 0.046 g (0.05 mmol) Sodium tert-butoxide (0.36 g, 3.7 mmol) was suspended in 180 ml of dehydrated toluene. Next, 0.12 ml of a toluene solution containing 0.12 mmol of tri (tert-butyl) phosphine was added, and the mixture was stirred at 100 ° C. for 46 hours. After cooling to room temperature, 150 ml of water was added to the reaction solution, and the mixture was extracted with chloroform. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography and recrystallized from dichloromethane-methanol to obtain the target compound (12) as a white powder (yield 2.03 g, yield 100%). Further, purification by sublimation was performed to obtain a product having a purity of 97.9% (purity confirmed by high performance liquid chromatography (HPLC)).

In addition, when the obtained compound was subjected to mass spectrometry, a peak was confirmed at m / z = 823 (M ⁺ ). Moreover, when this compound was analyzed using the infrared absorption spectroscopy (IR) method, IR spectrum shown in FIG. 6 was obtained. Furthermore, it was analyzed using the compound ¹ H- nuclear magnetic resonance ⁽¹ H-NMR) method, ¹ H-NMR spectrum shown in Figure 7 is ^obtained, 13 C-nuclear magnetic resonance ⁽¹ H-NMR) When analyzed by the method, the ¹³ C-NMR spectrum shown in FIG. 8 was obtained. Thus, it was confirmed that the compound obtained in Synthesis Example 2 was the compound (12).

<Synthesis Example 3>
The following compound (13) was synthesized by the following method. The reaction formula is shown below.

(Synthesis of Compound (1-5))
Under an argon stream, 2.81 g (30.0 mmol) of 2,3-dihydroxynaphthalene, 4.77 g (30.0 mmol) of 3,4-difluoronitrobenzene, and 8.29 g (60.0 mmol) of potassium carbonate were dehydrated with 30 ml of dehydrated toluene. The suspension was suspended in a mixed solution of 130 ml of N, N′-dimethylformamide and stirred at 100 ° C. for 18 hours. The reaction solution was cooled to room temperature and then added to 400 ml of water, and the precipitated solid was filtered and washed with methanol. The obtained solid was dried under reduced pressure to obtain a yellow powder (yield: 7.12 g, yield: 85%) of the target compound (1-5).

(Synthesis of Compound (1-6))
5.59 g (20.0 mmol) of the compound (1-5) synthesized by the above reaction was dissolved in 400 ml of tetrahydrofuran. Next, 50 ml of concentrated hydrochloric acid containing 18.05 g (80.0 mmol) of tin chloride dihydrate was slowly added, and the mixture was stirred for 3 hours with heating under reflux. After cooling the reaction solution, the precipitated solid was filtered and suspended in 200 ml of an aqueous sodium hydroxide solution, and the organic matter was extracted with chloroform. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography to obtain a brown powder (yield 4.20 g, 84% yield) of the target compound (1-6).

(Synthesis of Compound (1-7))
Dehydrated compound (1-6) 3.04 g (12.2 mmol), bromobenzene 1.88 g (12.0 mmol) and sodium tert-butoxide 1.38 g (14.4 mmol) synthesized by the above reaction under an argon stream. It was suspended in 200 ml of 1,4-dioxane. Next, 0.011 g (0.10 mmol) of palladium acetate, 0.07 g (0.15 mmol) of 2-dicyclohexylphosphino-2 ′, 4 ′, 6′-triisopropylbiphenyl (X-Phos), 10 μl of water 1 2,4-dioxane solution was added and stirred at 100 ° C. for 65 hours. The reaction solution was cooled to room temperature and concentrated under reduced pressure. 100 ml of methanol was added and filtered, and the resulting crude product was purified by column chromatography and recrystallized from dichloromethane / methanol to give a white powder of the desired compound (1-7) (yield 3.23 g, yield 83). %).

(Synthesis of Compound (13))
1.71 g (5.3 mmol) of the compound (1-7) synthesized by the above reaction under an argon stream, 0.78 g (2.5 mmol) of 4,4′-diiodobiphenyl, tris (dibenzylideneacetone) dipalladium (0) 0.046 g (0.05 mmol) and sodium tert-butoxide 1.20 g (12.5 mmol) were suspended in dehydrated toluene 120 ml. Next, 0.12 ml of a toluene solution containing 0.12 mmol of tri (tert-butyl) phosphine was added, and the mixture was stirred at 100 ° C. for 47 hours. The reaction solution was cooled to room temperature and concentrated under reduced pressure. 100 ml of methanol was added and filtered, and the resulting crude product was purified by column chromatography and then recrystallized from dichloromethane-methanol and toluene to give the desired compound (13) as a white powder (yield 1.84 g, yield 75). %). Further, purification by sublimation was performed to obtain a product having a purity of 99.0% (confirmed by high performance liquid chromatography (HPLC)).

In addition, when the obtained compound was subjected to mass spectrometry, a peak was confirmed at m / z = 801 (M ⁺ ). Moreover, when this compound was analyzed using the infrared absorption spectroscopy (IR) method, IR spectrum shown in FIG. 9 was obtained. Furthermore, Analysis of this compound ¹ H- using nuclear magnetic resonance ⁽¹ H-NMR) method, ¹ H-NMR spectrum shown in Figure 10 is ^obtained, 13 C-nuclear magnetic resonance ⁽¹ H-NMR) When analyzed by the method, the ¹³ C-NMR spectrum shown in FIG. 11 was obtained. Thus, it was confirmed that the compound obtained in Synthesis Example 3 was the compound (13).

<Synthesis Example 4>
The following compound (14) was synthesized by the following method. The reaction formula is shown below.

(Synthesis of N, N- (4-biphenylyl) phenyl-4′-bromobiphenyl-4-yl-amine (1-8))
Under an argon stream, (4-biphenylyl) phenylamine 2.45 g (10.0 mmol), 4-bromo-4′-iodobiphenyl 3.95 g (11.0 mmol), copper iodide 0.29 g (1.5 mmol), 0.27 g (1.5 mmol) of 1,10-phenanthroline and 1.68 g (15.0 mmol) of potassium tert-butoxide were suspended in 200 ml of dehydrated toluene and stirred at 100 ° C. for 113 hours. After cooling to room temperature, 200 ml of water was added to the reaction solution and extracted with toluene. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The obtained crude product was purified by column chromatography and recrystallized from dichloromethane / methanol to obtain the desired N, N- (4-biphenylyl) phenyl-4′-bromobiphenyl-4-yl-amine (1-8). ) White powder (yield 4.21 g, yield 88%).

(Synthesis of Compound (14))
1.48 g (3.1 mmol) of N, N- (4-biphenylyl) phenyl-4′-bromobiphenyl-4-yl-amine (1-8) synthesized by the above reaction under an argon stream, compound (1- 7) 0.98 g (3.0 mmol) and sodium tert-butoxide 0.35 g (3.6 mmol) were suspended in 150 ml of dehydrated 1,4-dioxane. Next, 0.007 g (0.03 mmol) of palladium acetate, 0.043 g (0.09 mmol) of 2-dicyclohexylphosphino-2 ′, 4 ′, 6′-triisopropylbiphenyl (X-Phos), 3 μl of water 1 2,4-dioxane solution was added and stirred at 100 ° C. for 20 hours. The reaction solution was cooled to room temperature and concentrated under reduced pressure. 100 ml of methanol was added and filtered, and the resulting crude product was purified by column chromatography and then recrystallized from dichloromethane / methanol to give the desired compound (14) as a white powder (yield 1.79 g, 83%). Got. Further, purification by sublimation was performed to obtain a product having a purity of 99.5% (confirmed by high performance liquid chromatography (HPLC)).

In addition, when the obtained compound was subjected to mass spectrometry, a peak was confirmed at m / z = 721 (M ⁺ ). Moreover, when this compound was analyzed using the infrared absorption spectroscopy (IR) method, IR spectrum shown in FIG. 12 was obtained. Furthermore, it was analyzed using the compound ¹ H- nuclear magnetic resonance ⁽¹ H-NMR) method, ¹ H-NMR spectrum shown in Figure 13 is ^obtained, 13 C-nuclear magnetic resonance ⁽¹ H-NMR) When analyzed by the method, the ¹³ C-NMR spectrum shown in FIG. 14 was obtained. Thus, it was confirmed that the compound obtained in Synthesis Example 4 was the compound (14).

<Example 1>
An ITO transparent electrode having a thickness of 100 nm was formed on a glass substrate by RF sputtering and patterned. This glass substrate with an ITO transparent electrode was subjected to ultrasonic cleaning using a neutral detergent, acetone and ethanol, and then pulled up from boiling ethanol and dried. After the surface of the transparent electrode was washed with UV / O _3, it was fixed to a substrate holder of a vacuum deposition apparatus, and the inside of the tank was depressurized to 1 × 10 ⁻⁴ Pa or less.

  Next, while maintaining the reduced pressure state, the compound (11) was deposited at a deposition rate of 0.1 nm / sec to a thickness of 30 nm to form a hole injection layer.

  Next, N, N, N ′, N′-tetrakis (3-biphenylyl) -1,1′-biphenyl-4,4′-diamine (21) having the following structure was deposited while maintaining the reduced pressure state. Vapor deposition was performed at a thickness of 80 nm at 0.1 nm / sec to form a hole transport layer.

  Further, while maintaining the reduced pressure state, the compound (22) having the following structure and the compound (23) having the following structure as a dopant were mixed at a mass ratio of 97: 3 and the overall deposition rate was 0.1 nm / It was vapor-deposited to 40 nm thickness as sec, and it was set as the light emitting layer.

Further, while maintaining the reduced pressure state, the compound (22) was successively deposited to a thickness of 20 nm at a deposition rate of 0.1 nm / sec, and Alq ₃ was successively deposited to a thickness of 10 nm at a deposition rate of 0.1 nm / sec. An injection transport layer was obtained.

  Next, LiF is deposited at a deposition rate of 0.1 nm / sec to a thickness of 0.5 nm, used as an electron injection electrode, Al is deposited as a protective electrode to a thickness of 100 nm, and finally glass sealed to organic electroluminescence. An element was obtained. The sublimation purification of the compound (11) can be performed at any stage as long as it is before vapor deposition.

When a direct current was applied to the organic electroluminescence device, blue-green light emission was confirmed. The light emission characteristics at a current density of 10 mA / cm ² are shown in Table 1.

<Example 2>
An ITO transparent electrode having a thickness of 100 nm was formed on a glass substrate by RF sputtering and patterned. This glass substrate with an ITO transparent electrode was subjected to ultrasonic cleaning using a neutral detergent, acetone and ethanol, and then pulled up from boiling ethanol and dried. After the surface of the transparent electrode was washed with UV / O _3, it was fixed to a substrate holder of a vacuum deposition apparatus, and the inside of the tank was depressurized to 1 × 10 ⁻⁴ Pa or less.

  Next, N, N′-diphenyl-N, N′-bis {4- [N- (4-methylphenyl) -N-phenylamino] phenyl} -1, having the following structure, while maintaining the reduced pressure state, 1′-biphenyl-4,4′-diamine (24) was deposited to a thickness of 30 nm at a deposition rate of 0.1 nm / sec to form a hole injection layer.

  Next, while maintaining the reduced pressure state, the compound (11) was deposited to a thickness of 80 nm at a deposition rate of 0.1 nm / sec to form a hole transport layer.

  Furthermore, while maintaining the reduced pressure state, the compound (22) and the compound (23) as a dopant were vapor-deposited to a thickness of 40 nm at a mass ratio of 97: 3 with an overall vapor deposition rate of 0.1 nm / sec. A light emitting layer was obtained.

Further, while maintaining the reduced pressure state, the compound (22) was successively deposited to a thickness of 20 nm at a deposition rate of 0.1 nm / sec, and Alq ₃ was successively deposited to a thickness of 10 nm at a deposition rate of 0.1 nm / sec. An injection transport layer was obtained.

  Next, LiF is deposited at a deposition rate of 0.1 nm / sec to a thickness of 0.5 nm, used as an electron injection electrode, Al is deposited as a protective electrode to a thickness of 100 nm, and finally glass sealed to organic electroluminescence. An element was obtained. The sublimation purification of the compound (11) can be performed at any stage as long as it is before vapor deposition.

When a direct current was applied to the organic electroluminescence device, blue-green light emission was confirmed. The light emission characteristics at a current density of 10 mA / cm ² are shown in Table 1.

<Example 3>
An ITO transparent electrode having a thickness of 100 nm was formed on a glass substrate by RF sputtering and patterned. This glass substrate with an ITO transparent electrode was subjected to ultrasonic cleaning using a neutral detergent, acetone and ethanol, and then pulled up from boiling ethanol and dried. After the surface of the transparent electrode was washed with UV / O _3, it was fixed to a substrate holder of a vacuum deposition apparatus, and the inside of the tank was depressurized to 1 × 10 ⁻⁴ Pa or less.

  Next, while maintaining the reduced pressure state, the compound (11) was deposited at a deposition rate of 0.1 nm / sec to a thickness of 1100 nm to form a hole injecting and transporting layer.

  Furthermore, while maintaining the reduced pressure state, the compound (22) and the compound (23) as a dopant were vapor-deposited to a thickness of 40 nm at a mass ratio of 97: 3 with an overall vapor deposition rate of 0.1 nm / sec. A light emitting layer was obtained.

Further, while maintaining the reduced pressure state, the compound (22) was successively deposited to a thickness of 20 nm at a deposition rate of 0.1 nm / sec, and Alq ₃ was successively deposited to a thickness of 10 nm at a deposition rate of 0.1 nm / sec. An injection transport layer was obtained.

  Next, LiF is deposited at a deposition rate of 0.1 nm / sec to a thickness of 0.5 nm, used as an electron injection electrode, Al is deposited as a protective electrode to a thickness of 100 nm, and finally glass sealed to organic electroluminescence. An element was obtained. The sublimation purification of the compound (11) can be performed at any stage as long as it is before vapor deposition.

When a direct current was applied to the organic electroluminescence device, blue-green light emission was confirmed. The light emission characteristics at a current density of 10 mA / cm ² are shown in Table 1.

<Example 4>
An ITO transparent electrode having a thickness of 100 nm was formed on a glass substrate by RF sputtering and patterned. This glass substrate with an ITO transparent electrode was subjected to ultrasonic cleaning using a neutral detergent, acetone and ethanol, and then pulled up from boiling ethanol and dried. After the surface of the transparent electrode was washed with UV / O _3, it was fixed to a substrate holder of a vacuum deposition apparatus, and the inside of the tank was depressurized to 1 × 10 ⁻⁴ Pa or less.

  Next, while maintaining the reduced pressure state, the compound (11) was deposited at a deposition rate of 0.1 nm / sec to a thickness of 1100 nm to form a hole injecting and transporting layer.

  Further, while maintaining the reduced pressure state, the compound (11), the compound (22), and the compound (23) as a dopant were mixed at a mass ratio of 80: 20: 3, and the overall deposition rate was 0.1 nm / sec. As a light emitting layer.

Further, while maintaining the reduced pressure state, the compound (22) was successively deposited to a thickness of 20 nm at a deposition rate of 0.1 nm / sec, and Alq ₃ was successively deposited to a thickness of 10 nm at a deposition rate of 0.1 nm / sec. An injection transport layer was obtained.

  Next, LiF is deposited at a deposition rate of 0.1 nm / sec to a thickness of 0.5 nm, used as an electron injection electrode, Al is deposited as a protective electrode to a thickness of 100 nm, and finally glass sealed to organic electroluminescence. An element was obtained. The sublimation purification of the compound (11) can be performed at any stage as long as it is before vapor deposition.

When a direct current was applied to the organic electroluminescence device, blue-green light emission was confirmed. The light emission characteristics at a current density of 10 mA / cm ² are shown in Table 1.

<Example 5>
An organic electroluminescent element was produced in the same manner as in Example 1 except that the compound (12) was used in place of the compound (11) in Example 1. When a direct current was applied to the organic electroluminescence device, blue-green light emission was confirmed. The light emission characteristics at a current density of 10 mA / cm ² are shown in Table 1.

<Example 6>
An organic electroluminescent element was produced in the same manner as in Example 2 except that the compound (12) was used in place of the compound (11) in Example 2. When a direct current was applied to the organic electroluminescence device, blue-green light emission was confirmed. The light emission characteristics at a current density of 10 mA / cm ² are shown in Table 1.

<Example 7>
An organic electroluminescent element was produced in the same manner as in Example 3, except that the compound (12) was used in place of the compound (11) in Example 3. When a direct current was applied to the organic electroluminescence device, blue-green light emission was confirmed. The light emission characteristics at a current density of 10 mA / cm ² are shown in Table 1.

<Example 8>
An organic electroluminescent element was produced in the same manner as in Example 1 except that the compound (13) was used in place of the compound (11) in Example 1. When a direct current was applied to the organic electroluminescence device, blue-green light emission was confirmed. The light emission characteristics at a current density of 10 mA / cm ² are shown in Table 1.

<Example 9>
An organic electroluminescent device was produced in the same manner as in Example 2 except that the compound (13) was used instead of the compound (11) in Example 2. When a direct current was applied to the organic electroluminescence device, blue-green light emission was confirmed. The light emission characteristics at a current density of 10 mA / cm ² are shown in Table 1.

<Example 10>
An organic electroluminescent element was produced in the same manner as in Example 3, except that the compound (13) was used instead of the compound (11) in Example 3. When a direct current was applied to the organic electroluminescence device, blue-green light emission was confirmed. The light emission characteristics at a current density of 10 mA / cm ² are shown in Table 1.

<Example 11>
An organic electroluminescent device was produced in the same manner as in Example 1 except that the compound (14) was used instead of the compound (11) in Example 1. When a direct current was applied to the organic electroluminescence device, blue-green light emission was confirmed. The light emission characteristics at a current density of 10 mA / cm ² are shown in Table 1.

<Example 12>
An organic electroluminescent device was produced in the same manner as in Example 2 except that the compound (14) was used instead of the compound (11) in Example 2. When a direct current was applied to the organic electroluminescence device, blue-green light emission was confirmed. The light emission characteristics at a current density of 10 mA / cm ² are shown in Table 1.

<Example 13>
An organic electroluminescent element was produced in the same manner as in Example 3 except that the compound (14) was used in place of the compound (11) in Example 3. When a direct current was applied to the organic electroluminescence device, blue-green light emission was confirmed. The light emission characteristics at a current density of 10 mA / cm ² are shown in Table 1.

<Comparative Example 1>
An organic electroluminescent element was produced in the same manner as in Example 1 except that the compound (24) was used in place of the compound (11) in Example 1. When a direct current was applied to the organic electroluminescence device, blue-green light emission was confirmed. The light emission characteristics at a current density of 10 mA / cm ² are shown in Table 1.

<Comparative example 2>
Except for using 2,7-bis (N, N-diphenylamino) dibenzo [b, e] [1,4] dioxin (25) having the following structure in place of the compound (11) of Example 3. In the same manner as in Example 3, an organic electroluminescent element was produced. When a direct current was applied to the organic electroluminescence device, blue-green light emission was confirmed. The light emission characteristics at a current density of 10 mA / cm ² are shown in Table 1.

  The organic electroluminescent element in which the compound (11), (12), (13), or (14) is contained in the organic layer according to Examples 1 to 13 and Comparative Examples 1 to 2 is the compound (21) or the compound (24). ), Compared with the organic electroluminescence device containing the compound (25), it was shown that the driving voltage can be sufficiently reduced and the power consumption can be suppressed.

<Example 14>
When the organic electroluminescent element produced in Example 1 was stored at 85 ° C. and the light emission state after 300 hours was confirmed, it showed blue-green uniform light emission, and no change was seen in the uniformity of the light emitting surface before and after heating. It was.

<Example 15>
When the organic electroluminescent element produced in Example 5 was stored at 85 ° C. and the light emission state after 300 hours was confirmed, it showed blue-green uniform light emission, and no change was seen in the uniformity of the light emitting surface before and after heating. It was.

<Example 16>
When the organic electroluminescent element produced in Example 8 was stored at 85 ° C. and the light emitting state after 300 hours was confirmed, it showed blue-green uniform light emission, and no change was seen in the uniformity of the light emitting surface before and after heating. It was.

<Example 17>
When the organic electroluminescent element produced in Example 11 was stored at 85 ° C. and the light emission state after 300 hours was confirmed, it showed blue-green uniform light emission, and no change was seen in the uniformity of the light emitting surface before and after heating. It was.

<Comparative Example 3>
An organic electroluminescent element was produced in the same manner as in Example 1 except that the compound (21) was used instead of the compound (11) in Example 1. When this organic electroluminescent element was stored at 85 ° C. and the light emitting state after 300 hours was confirmed, a non-uniform light emitting surface was observed.

<Comparative example 4>
When the organic electroluminescent element produced in Comparative Example 1 was stored at 85 ° C. and the light emitting state after 300 hours was confirmed, a non-uniform light emitting surface was observed.

<Comparative Example 5>
When the organic electroluminescent element produced in Comparative Example 2 was stored at 85 ° C. and the light emitting state after 300 hours was confirmed, a non-uniform light emitting surface was observed.

  According to Examples 14 to 17 and Comparative Examples 3 to 5, compound (11), (12), (13) or (14) is compared with compound (21), compound (24) or compound (25), In order to form a uniform thin film with high adhesion to the anode and maintain a stable and uniform light-emitting surface even when stored at high temperatures, holes are injected into the compound (11), (12), (13) or (14). Compared with the organic electroluminescent element containing the compound (21), the compound (24), and the compound (25), the organic electroluminescent element included in the layer 14 can sufficiently reduce the driving voltage and suppresses power consumption. It was shown to be possible.

  As described above in detail, the organic electroluminescent element compound of the present invention can sufficiently reduce the driving voltage of the organic electroluminescent element by containing it in the organic thin film layer, and has low power consumption. An organic electroluminescent element can be realized.

DESCRIPTION OF SYMBOLS 1 ... 1st electrode, 2 ... 2nd electrode, 4 ... Substrate, 10 ... Light emitting layer, 11 ... Hole transport layer, 13 ... Electron injection transport layer, 14 * ... Hole injection layer, 100... Organic electroluminescence device according to the first embodiment, 200... Organic electroluminescence device according to the second embodiment, P.

Claims (3)

A compound represented by the following general formula (1).
[Wherein R ₁ represents a hydrogen atom . a = 4 and b = 2 . At least one of Ar _{1 to} Ar ₄ is represented by the following general formula (2) or (3).
(In the formula, R ₂ and R ₃ represent a hydrogen atom. L ₁ represents a single bond . C = 4 and d = 3. )
(In the formula, R ₄ and R ₅ are hydrogen. L ₂ is a single bond . E = 6 and f = 3. ) In the general formula (1), Ar _{1 to} Ar ₄ Among them, those not represented by the general formula (2) or (3) each independently represent a phenyl group or a biphenylyl group . ] The compound according to claim 1, wherein two of Ar _{1 to} Ar ₄ are groups represented by the general formula (2) or (3). 3. An organic electroluminescent device comprising at least a light emitting layer sandwiched between a pair of electrodes consisting of an anode and a cathode, comprising the compound according to claim 1 or 2.