JP2012204793A - Organic electroluminescent element and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescent element and a display device in which current density dependence of chromaticity and an increase in driving voltage can be suppressed.SOLUTION: The organic electroluminescent element comprises an organic layer 14 between an anode 13 and a cathode 15. The organic layer 14 is composed of a hole supply layer 14A, a light-emitting layer 14B, and an electron supply layer 14C. The electron supply layer 14C contains a nitrogen-containing heterocyclic compound having an electron mobility of 1.0×10cm/Vs or more. By using the compound having high electron mobility in the electron supply layer 14C, a carrier balance between holes and electrons in each light-emitting layer is adjusted.

Description

  The present invention relates to an organic electroluminescent element that emits light using an organic electroluminescence (EL) phenomenon and a display device.

  White organic electroluminescent elements can be used for lighting and full-color display devices using color filters, etc., and the manufacturing process is easier compared to white elements produced by RGB coating, so active development is underway. It has been broken.

  When this white organic electroluminescent element is used in a full color display device, the red, green and blue light emitting layers constituting the light emitting layer of the white organic electroluminescent element have high color purity and emit light uniformly. It is demanded to make it. Thus, for example, Patent Document 1 discloses an organic electroluminescence device that can stably obtain blue light emission by using a compound having hole injection / transport properties and / or electron injection / transport properties as a host compound in a blue light-emitting layer. It has been applied to full-color display devices.

JP 2006-140434 A

  However, in conventional organic electroluminescent devices such as the organic electroluminescent device listed in Patent Document 1, the carrier balance in the light emitting layer of each color changes due to the change in current density, and the chromaticity change due to the exciton distribution change occurs. There was a problem that happened. For high-efficiency RGB light emission in a full-color display device, it is necessary to reduce the chromaticity change, that is, to adjust the carrier balance. The carrier balance can be adjusted, for example, by adjusting the film thickness of the light emitting layer. However, since the film thickness is 1 nm to 2 nm, which is equivalent to the molecular size of the compound constituting the light emitting layer, the control is possible. It was extremely difficult and an adjustment method other than the adjustment of the film thickness was required.

  Moreover, since an organic electroluminescent element has a diode characteristic, a current density changes with respect to a change in voltage. Further, the driving voltage of the organic electroluminescent element changes with time due to the increase of the resistance component in the organic electroluminescent element, and usually rises by 0.2V to 1V. Therefore, it is necessary to use a constant current driving circuit dedicated to the organic electroluminescence element in the active driving panel. Further, in order to use a cheaper constant voltage driving circuit, it is necessary to suppress a voltage increase due to driving to less than 0.1 V, more preferably to less than 0.05 V in order to obtain a constant current supply.

  The present invention has been made in view of such problems, and an object thereof is to use an organic electroluminescent element capable of suppressing the current density dependency of chromaticity and suppressing an increase in driving voltage, and the same. It is to provide a display device.

An organic electroluminescent device according to the present invention is an organic electroluminescent device comprising an organic layer having a plurality of light emitting layers exhibiting different emission colors between an anode and a cathode, wherein the light emitting layer contains at least an anthracene derivative. An electron supply layer made of a host material of at least species and containing a nitrogen-containing heterocyclic compound between the cathode and the light emitting layer and having an electron mobility of 1.0 × 10 ⁻⁴ cm ² / Vs or more It is what has.

  A display device according to the present invention includes a plurality of the organic electroluminescent elements provided on a substrate.

In the organic electroluminescent element of the present invention and the display device including the same, an electron supply layer including a nitrogen-containing heterocyclic compound is provided on a plurality of light-emitting layers having different emission colors including at least one anthracene derivative. In addition, since the electron mobility of the electron supply layer is 1.0 × 10 ⁻⁴ cm ² / Vs or more, the carrier balance of holes and electrons in each light emitting layer is adjusted.

The organic electroluminescent element of the present invention and the display device including the organic electroluminescent element include an organic layer having a plurality of light emitting layers exhibiting different emission colors between the anode and the cathode, and the light emitting layer includes at least two anthracene derivatives. The above host material is contained, and a nitrogen-containing heterocyclic compound is included between the cathode and the light emitting layer, and the electron mobility is 1.0 × 10 ⁻⁴ cm ² / Vs or more. Since the electron supply layer made of a high compound is provided, the carrier balance of holes and electrons in each light emitting layer is adjusted. Thereby, the change of exciton distribution is suppressed and the chromaticity change by the change of a current density is suppressed. Moreover, since excitons recombine only in the light emitting layer by adjusting the carrier balance, excitation of layers other than the light emitting layer can be suppressed. Thereby, generation | occurrence | production of the deterioration factor in an organic layer is reduced, and the raise of a drive voltage is suppressed.

It is sectional drawing of the organic electroluminescent element which concerns on the 1st Embodiment of this invention. It is a figure showing the structure of the display apparatus provided with the organic electroluminescent element shown in FIG. FIG. 3 is a diagram illustrating an example of a pixel drive circuit illustrated in FIG. 2. FIG. 3 is a diagram illustrating an example of a cross-sectional configuration of the display device illustrated in FIG. 2. It is an example of sectional drawing of the organic electroluminescent element which concerns on the 2nd Embodiment of this invention. It is another example of sectional drawing of the said organic electroluminescent element. It is sectional drawing of the organic electroluminescent element which concerns on the 3rd Embodiment of this invention. It is a top view showing schematic structure of the module containing the display apparatus of the said embodiment. It is a perspective view showing the external appearance of the application example 1 of the display apparatus of the said embodiment. (A) is a perspective view showing the external appearance seen from the front side of the application example 2, (B) is a perspective view showing the external appearance seen from the back side. 12 is a perspective view illustrating an appearance of application example 3. FIG. 14 is a perspective view illustrating an appearance of application example 4. FIG. (A) is a front view of the application example 5 in an open state, (B) is a side view thereof, (C) is a front view in a closed state, (D) is a left side view, and (E) is a right side view, (F) is a top view and (G) is a bottom view.

Embodiments of the present invention will be described in detail in the following order with reference to the drawings.
1. First Embodiment (Organic electroluminescence device in which a single organic layer including a hole supply layer, a light emitting layer and two electron supply layers is sandwiched between an anode and a cathode)
1-1 (organic electroluminescence device)
1-2 (display device)
2. Second Embodiment (Organic electroluminescence device having an organic layer including an electron supply layer consisting of three layers)
3. Third Embodiment (Organic electroluminescence device having an organic layer of tandem structure)

(First embodiment)
(Organic electroluminescence device)
FIG. 1 shows a cross-sectional configuration of an organic electroluminescent element 11 according to a first embodiment of the present invention. The organic electroluminescent element 11 has a structure in which an anode 13, an organic layer 14, and a cathode 15 are laminated on a substrate 12 in this order. Of these layers, the organic layer 14 includes, for example, a hole supply layer 14A (a hole injection layer 14a and a hole transport layer 14b), a light emitting layer 14B, and an electron supply layer 14C (a first layer 14c and a second layer 14d) in order from the anode 13 side. ).

  This organic electroluminescent element 11 emits light generated when holes injected from the anode 13 and electrons injected from the cathode 15 recombine in the light emitting layer 14B on the side opposite to the substrate 12 (cathode 15). This is an organic electroluminescence device of a top emission method (top emission method) that extracts light from the side).

  The substrate 12 is a support on which the organic electroluminescent elements 11 are arranged and formed on one main surface side. The material constituting the substrate 12 may be a known material, for example, quartz, glass, metal foil, or a resin film or sheet. Of these, quartz and glass are preferable. In the case of resin, methacrylic resins represented by polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene naphthalate ( Polyesters such as PBN) or polycarbonate resins. However, in order to suppress water permeability and gas permeability, a laminated structure or surface treatment is required.

The anode 13 preferably has a high work function from the vacuum level of the electrode material in order to inject holes efficiently. Specifically, for example, chromium (Cr), gold (Au), an alloy of tin oxide (SnO ₂ ) and antimony (Sb), an alloy of zinc oxide (ZnO) and aluminum (Al), a silver (Ag) alloy Alternatively, oxides of these metals and alloys can be used alone or in a mixed state.

  Further, the anode 13 may have a laminated structure of a first layer having excellent light reflectivity and a second layer having a light transmittance and a large work function provided thereon. Here, it is preferable to use an alloy mainly containing Al as the first layer. As the subcomponent, an element having a work function relatively smaller than that of Al as the main component is used. As such a minor component, it is preferable to use a lanthanoid series element. The work function of the lanthanoid series elements is not large, but inclusion of these elements improves the stability of the anode and improves the hole injection property of the anode. In addition to lanthanoid series elements, elements such as silicon (Si) and copper (Cu) may be used as subcomponents.

  The content of subcomponents in the Al alloy layer constituting the first layer is, for example, about 10 wt% or less in total in the case of neodymium (Nd), nickel (Ni), titanium (Ti) or the like that stabilizes Al. It is preferable. Thereby, the Al alloy layer can be stably maintained in the manufacturing process of the organic electroluminescent element while maintaining the reflectance in the Al alloy layer as the first layer. Further, processing accuracy and chemical stability can be obtained. Furthermore, the conductivity of the anode 13 and the adhesion to the substrate 12 are also improved. Since the metal such as Nd has a small work function, an amine-based material generally used for the hole supply layer 14A described later has a large hole injection barrier. In that case, a layer in which an acceptor material such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (F4-TCNQ) is mixed with an amine material, By forming a p-doped layer such as oxythiophene-polystyrene sulfonic acid (PEDOT-PSS) at the interface of the anode 13, the hole injection barrier can be reduced, and an increase in driving voltage can be suppressed. In addition, by using an azatriphenylene derivative described later, it is possible to stabilize the element while suppressing an increase in driving voltage.

  For the second layer, an oxide of Al alloy, an oxide of molybdenum (Mo), an oxide of zirconium (Zr), an oxide of Cr, and an oxide of tantalum (Ta) can be used. For example, in the case where the second layer is an Al alloy oxide layer (including a natural oxide film) containing a lanthanoid series element as a subcomponent, the lanthanoid series element oxide contains this because it has a high light transmittance. The light transmittance of the second layer is improved. Thereby, the reflectance at the surface of the first layer is kept high. Moreover, the electron injection characteristic of the anode 13 is improved by using a transparent conductive layer such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide) for the second layer. In addition, since ITO and IZO have a large work function, it is possible to improve the carrier injection efficiency and improve the adhesion between the anode 13 and the substrate 12 by using the ITO and IZO on the side in contact with the substrate 12, that is, the first layer. it can.

  When the driving method of the display device configured using the organic electroluminescent element 11 is an active matrix method, the anode 13 is patterned for each pixel and is a driving thin film transistor (illustrated) provided on the substrate 12. No connection). In this case, a partition 16 (see FIG. 4) is provided on the anode 13, and the surface of the anode 13 of each pixel is exposed from the opening of the partition 16.

  The hole supply layer 14A (the hole injection layer 14a and the hole transport layer 14b) is a buffer layer for increasing the efficiency of hole injection into the light emitting layer 14B and preventing leakage. The film thickness of the hole supply layer 14A depends on the overall structure of the device, particularly the relationship with the electron supply layer 14C described later, but is preferably 5 nm to 300 nm, for example, and more preferably 10 nm to 200 nm.

  The constituent material of the hole supply layer 14A may be appropriately selected in relation to the electrode and the material of the adjacent layer. For example, benzine, styrylamine, triphenylamine, porphyrin, triphenylene, azatriphenylene, tetracyanoquinodimethane. , Triazole, imidazole, oxadiazole, polyarylalkane, phenylenediamine, arylamine, oxazole, anthracene, fluorenone, hydrazone, stilbene or their derivatives, or polysilane compounds, vinylcarbazole compounds, thiophene compounds or aniline compounds Heterocyclic conjugated monomers, oligomers or polymers such as compounds can be used.

  Further, specific materials for the hole supply layer 14A include α-naphthylphenylphenylenediamine, porphyrin, metal tetraphenylporphyrin, metal naphthalocyanine, hexacyanoazatriphenylene, 7,7,8,8-tetracyanoquino. Dimethane (TCNQ), F4-TCNQ, tetracyano 4,4,4-tris (3-methylphenylphenylamino) triphenylamine, N, N, N ′, N′-tetrakis (p-tolyl) p-phenylenediamine , N, N, N ′, N′-tetraphenyl-4,4′-diaminobiphenyl, N-phenylcarbazole, 4-di-p-tolylaminostilbene, poly (paraphenylene vinylene), poly (thiophene vinylene), And poly (2,2′-thienylpyrrole).

  However, by using the compounds represented by the following formulas (2) to (5), holes supplied from the hole supply layer 14A to the light emitting layer 14B with respect to the electron supply from the electron supply layer 14C described later to the light emitting layer 14B. Supply is optimized.

（Ｒ１〜Ｒ６は各々独立して、水素原子、ハロゲン原子、ヒドロキシル基、アミノ基、アリールアミノ基、炭素数２０以下のカルボニル基、炭素数２０以下のカルボニルエステル基、炭素数２０以下のアルキル基、炭素数２０以下のアルケニル基、炭素数２０以下のアルコキシル基、炭素数３０以下のアリール基、炭素数３０以下の複素環基、ニトリル基、シアノ基、ニトロ基、またはシリル基から選ばれる置換基あるいはそれらの誘導体である。隣接するＲ１〜Ｒ６は互いに結合して環状構造を形成してもよい。Ｘ１〜Ｘ６は各々独立して、炭素原子または窒素原子である。）

(R1 to R6 are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, an arylamino group, a carbonyl group having 20 or less carbon atoms, a carbonyl ester group having 20 or less carbon atoms, or an alkyl group having 20 or less carbon atoms. A substituent selected from an alkenyl group having 20 or less carbon atoms, an alkoxyl group having 20 or less carbon atoms, an aryl group having 30 or less carbon atoms, a heterocyclic group having 30 or less carbon atoms, a nitrile group, a cyano group, a nitro group, or a silyl group And adjacent R1 to R6 may be bonded to each other to form a cyclic structure. X1 to X6 are each independently a carbon atom or a nitrogen atom.)

  Note that the azatriphenylene derivative represented by the above formula (2) is preferably used for the hole injection layer 14a because X is replaced by a nitrogen atom to increase the nitrogen content in the compound.

（Ａ０〜Ａ２は、各々独立して、水素原子、ハロゲン原子、ヒドロキシル基、アルデヒド基、カルボニル基、カルボニルエステル基、アルキル基、アルケニル基、環状アルキル基、アルコキシ基、アリール基、アミノ基、複素環基、シアノ基、ニトリル基、ニトロ基、あるいはシリル基によって置換された炭素数６〜３０の芳香族炭化水素基である。）

(A0 to A2 are each independently a hydrogen atom, halogen atom, hydroxyl group, aldehyde group, carbonyl group, carbonyl ester group, alkyl group, alkenyl group, cyclic alkyl group, alkoxy group, aryl group, amino group, complex, (It is an aromatic hydrocarbon group having 6 to 30 carbon atoms substituted by a cyclic group, a cyano group, a nitrile group, a nitro group, or a silyl group.)

（Ａ３〜Ａ６は、各々独立して、水素原子、ハロゲン原子、ヒドロキシル基、アルデヒド基、カルボニル基、カルボニルエステル基、アルキル基、アルケニル基、環状アルキル基、アルコキシ基、アリール基、アミノ基、複素環基、シアノ基、ニトリル基、ニトロ基、あるいはシリル基によって置換された炭素数６〜２０の芳香族炭化水素基である。Ａ３およびＡ４、Ａ５およびＡ６は各々連結基を介して結合していてもよい。ＹはＮとの結合部位以外の環炭素に、各々独立して水素原子、ハロゲン原子、ヒドロキシル基、アルデヒド基、カルボニル基、カルボニルエステル基、アルキル基、アルケニル基、環状アルキル基、アルコキシ基、アリール基、アミノ基、複素環基、シアノ基、ニトリル基、ニトロ基、またはシリル基によって置換されたベンゼン、ナフタレン、アントラセン、フェナントレン、ナフタセン、フルオランテンまたはペリレンからなる２価の芳香族炭化水素基である。ｍは１以上の整数である。）

(A3 to A6 are each independently a hydrogen atom, halogen atom, hydroxyl group, aldehyde group, carbonyl group, carbonyl ester group, alkyl group, alkenyl group, cyclic alkyl group, alkoxy group, aryl group, amino group, An aromatic hydrocarbon group having 6 to 20 carbon atoms substituted by a cyclic group, a cyano group, a nitrile group, a nitro group, or a silyl group, A3 and A4, A5 and A6 are bonded via a linking group. Y may be independently a hydrogen atom, a halogen atom, a hydroxyl group, an aldehyde group, a carbonyl group, a carbonyl ester group, an alkyl group, an alkenyl group, a cyclic alkyl group, or a ring carbon other than the bonding site with N. Substituted by alkoxy group, aryl group, amino group, heterocyclic group, cyano group, nitrile group, nitro group, or silyl group Benzene, naphthalene, anthracene, phenanthrene, naphthacene, a divalent aromatic hydrocarbon radical consisting of fluoranthene or perylene .m is an integer of 1 or more.)

（Ａ７〜Ａ１２は各々独立して水素原子、ハロゲン原子、ヒドロキシル基、アルデヒド基、カルボニル基、カルボニルエステル基、アルキル基、アルケニル基、環状アルキル基、アルコキシ基、アリール基、アミノ基、複素環基、シアノ基、ニトリル基、ニトロ基、あるいはシリル基によって置換された炭素数６〜２０の芳香族炭化水素基である。隣接するＡ７およびＡ８、Ａ９およびＡ１０、Ａ１１およびＡ１２は、各々連結基を介して結合していてもよい。Ｚ１〜Ｚ３はＮとの結合部位以外の環炭素に、各々独立して水素原子、ハロゲン原子、ヒドロキシル基、アルデヒド基、カルボニル基、カルボニルエステル基、アルキル基、アルケニル基、環状アルキル基、アルコキシ基、アリール基、アミノ基、複素環基、シアノ基、ニトリル基、ニトロ基、またはシリル基によって置換されたベンゼン、ナフタレン、アントラセン、フェナントレン、ナフタセン、フルオランテンまたはペリレンからなる２価の芳香族炭化水素基である。ｐ、ｑおよびｒは１以上の整数である。）

(A7 to A12 are each independently hydrogen atom, halogen atom, hydroxyl group, aldehyde group, carbonyl group, carbonyl ester group, alkyl group, alkenyl group, cyclic alkyl group, alkoxy group, aryl group, amino group, heterocyclic group. , An aromatic hydrocarbon group having 6 to 20 carbon atoms substituted by a cyano group, a nitrile group, a nitro group, or a silyl group, and adjacent A7 and A8, A9 and A10, A11 and A12 are each a linking group. Z1 to Z3 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an aldehyde group, a carbonyl group, a carbonyl ester group, an alkyl group, or a ring carbon other than the bonding site with N. Alkenyl group, cyclic alkyl group, alkoxy group, aryl group, amino group, heterocyclic group, cyano group, nitrile group Benzene substituted by a nitro group or a silyl group, naphthalene, anthracene, phenanthrene, naphthacene, a divalent aromatic hydrocarbon radical consisting of fluoranthene or perylene .p, q and r is an integer of 1 or more.)

  Specific examples of the azatriphenylene derivative represented by the formula (2) include compounds such as the following formula (2-1).

  Specific examples of the amine derivative represented by the formula (3) include compounds such as the following formulas (3-1) to (3-9).

  Specific examples of the diamine derivative represented by the formula (4) include compounds such as the following formulas (4-1) to (4-84).

  Specific examples of the triarylamine multimer represented by the formula (5) include compounds such as the following formulas (5-1) to (5-15).

  These compounds may be used in either the hole injection layer 14a or the hole transport layer 14b, but it is preferable to use a compound having a high nitrogen content in the hole injection layer 14a.

  The light emitting layer 14 </ b> B is a region where holes injected from the anode 13 side and electrons injected from the cathode 15 side are recombined when an electric field is applied to the anode 13 and the cathode 15. The light emitting layer 14B is provided with a plurality of light emitting layers (here, three layers) 14r, 14g, and 14b having different emission colors. The light emitting layer 14r is a red light emitting layer, the light emitting layer 14g is a green light emitting layer, and the light emitting layer 14b is a blue light emitting layer. The stacking order of the light emitting layers 14r, 14g, and 14b is appropriately determined from the adjustment of the optical path length according to the carrier transport property of each of the light emitting layers 14r, 14g, and 14b and the emission wavelength of light extraction. Here, for example, a red light emitting layer 11r, a blue light emitting layer 11b, and a green light emitting layer 11g are stacked in this order from the anode 13 side. A light emitting layer separation layer (not shown) may be provided between the red light emitting layer 14r, the green light emitting layer 14g, and the blue light emitting layer 14b. The light emitting layer separation layer is made of, for example, an amine derivative, and the thickness is preferably 0.1 nm to 20 nm, and more preferably 1 to 10 nm. The thickness of the light emitting layer 14B is preferably 3 nm to 30 nm, and more preferably 5 nm to 20 nm, for example, although it depends on the overall structure of the element. Among these, it is preferable to set the film thickness of the light emitting layers 14r, 14g, and 14b of the respective colors as follows. For example, the red light emitting layer 14r is 5 nm to 15 nm, the green light emitting layer 14g is 5 nm to 15 nm, and the blue light emitting layer 14b is 5 nm to 15 nm, but is not limited thereto.

  The material constituting the light emitting layer 14B is a charge injection function (holes can be injected from the anode 13 or the hole supply layer 14A when an electric field is applied, and electrons can be injected from the cathode 15 or the electron supply layer 14C. Function), transport function (function to move injected holes and electrons by the force of electric field), light emission function (function to provide a field for recombination of electrons and holes and connect them to light emission) Is preferred.

  In particular, it is preferable to use a hole transporting material as a host material for the light emitting layer on the anode side of the plurality of light emitting layers 14r, 14g, and 14b. Thereby, the hole injection from the anode 13 is stabilized. Specific examples of such materials include styryl derivatives, anthracene derivatives, naphthacene derivatives, and aromatic amines. In particular, the styryl derivative is preferably a distil derivative, a tristil derivative, a tetrastil derivative, or a styrylamine derivative. Further, an excellent carrier balance can be maintained by using an anthracene derivative, particularly an asymmetric anthracene compound. Furthermore, the aromatic amine is preferably a compound having 2 to 4 nitrogen atoms substituted with an aromatic ring group. Among these, it is particularly preferable to use a polycyclic aromatic hydrocarbon compound having a mother skeleton having 4 to 7 ring members. Examples of the mother skeleton having 4 to 7 ring members include pyrene, benzopyrene, chrysene, naphthacene, benzonaphthacene, dibenzonaphthacene, perylene, and coronene.

  As the hole supply material, a compound represented by the following formula (6) can be used.

（Ｒ９〜Ｒ１６は各々独立して、水素原子、ハロゲン原子、ヒドロキシル基、炭素数１以上２０以下のカルボニル基、炭素数１以上２０以下のカルボニルエステル基、炭素数１以上２０以下アルキル基、炭素数１以上２０以下のアルケニル基、炭素数１以上２０以下のアルコキシル基、シアノ基、ニトロ基、炭素数５以上３０以下のシリル基、炭素数６以上３０以下のアリール基、複素環基または炭素数１以上３０以下のアミノ基、あるいはそれらの誘導体である。）

(R9 to R16 are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a carbonyl group having 1 to 20 carbon atoms, a carbonyl ester group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms, carbon, An alkenyl group having 1 to 20 carbon atoms, an alkoxyl group having 1 to 20 carbon atoms, a cyano group, a nitro group, a silyl group having 5 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, a heterocyclic group, or carbon An amino group having a number in the range of 1 to 30 or a derivative thereof.

  Specific examples of the compound represented by formula (6) include compounds such as the following formula (6-1) to formula (6-4).

  By using the hole transporting material as described above, hole injection from the anode 13 is stabilized. Of these hole transport materials, the ionization potential is particularly preferably less than 5.6 eV.

  The red light emitting layer 14r may use the hole transporting material, and the green light emitting layer 14g may use a fluorescent light emitting material or a phosphorescent light emitting material. As the fluorescent light emitting material (fluorescent host material), for example, an anthracene compound represented by the following formula (7) can be used. Examples of the phosphorescent light emitting material (phosphorescent host material) include carbazole derivatives and indolocarbazole derivatives.

  In the blue light-emitting layer 14b, for example, an anthracene compound is used as a host material, and a blue fluorescent dye guest material is doped therein, thereby generating blue light emission.

  In addition, as a host material which comprises the blue light emitting layer 14b and the green light emitting layer 14g, it is preferable to use the anthracene compound shown in following formula (7) as a host material.

（Ｂ１，Ｂ２は各々独立して、炭素数６以上２０以下の芳香族環基あるいはその誘導体である。Ｒ１〜Ｒ８は各々独立して、水素原子、ハロゲン原子、水酸基、シアノ基、ニトロ基、または炭素数５０以下のカルボニル基を有する基、カルボニルエステル基を有する基、アルキル基、アルケニル基、アルコキシル基あるいはそれらの誘導体、炭素数３０以下のシリル基を有する基、アリール基を有する基、複素環基を有する基、アミノ基を有する基あるいはそれらの誘導体である。）

(B1 and B2 are each independently an aromatic ring group having 6 to 20 carbon atoms or a derivative thereof. R1 to R8 are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, Or a group having a carbonyl group having 50 or less carbon atoms, a group having a carbonyl ester group, an alkyl group, an alkenyl group, an alkoxyl group or a derivative thereof, a group having a silyl group having 30 or less carbon atoms, a group having an aryl group, a complex A group having a cyclic group, a group having an amino group, or a derivative thereof.)

  Examples of the group having an aryl group represented by R1 to R8 in the compound represented by the formula (7) include a phenyl group, 1-naphthyl group, 2-naphthyl group, fluorenyl group, 1-anthryl group, 2-anthryl group, 9-anthryl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthryl group, 1-naphthacenyl group, 2-naphthacenyl group, 9-naphthacenyl group, 1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group, 1-chrycenyl group, 6-chrycenyl group, 2-fluoranthenyl group, 3-fluoranthenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl Group, o-tolyl group, m-tolyl group, p-tolyl group, pt-butylphenyl group and the like.

  The group having a heterocyclic group represented by R1 to R8 is a 5-membered or 6-membered aromatic ring group containing an oxygen atom (O), a nitrogen atom (N), or a sulfur atom (S) as a hetero atom. And a condensed polycyclic aromatic ring group having 2 to 20 carbon atoms. Examples of such heterocyclic groups include thienyl group, furyl group, pyrrolyl group, pyridyl group, quinolyl group, quinoxalyl group, imidazopyridyl group, and benzothiazole group. Typical examples include 1-pyrrolyl group, 2-pyrrolyl group, 3-pyrrolyl group, pyrazinyl group, 2-pyridinyl group, 3-pyridinyl group, 4-pyridinyl group, 1-indolyl group, 2-indolyl group, 3-indolyl group, 4-indolyl group, 5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolyl group, 2-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group, 5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group, 2-furyl group, 3-furyl group, 2-benzofuranyl group, 3-benzofuranyl group, 4-benzofuranyl group, 5-benzofuranyl group, 6-benzofuranyl group, 7-benzofuranyl group, 1-isobenzofuranyl group, 3-isobenzofuranyl group, 4-isobenzofuranyl group, 5-isobefuranyl group Zofuranyl group, 6-isobenzofuranyl group, 7-isobenzofuranyl group, quinolyl group, 3-quinolyl group, 4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group, 8-quinolyl group Group, 1-isoquinolyl group, 3-isoquinolyl group, 4-isoquinolyl group, 5-isoquinolyl group, 6-isoquinolyl group, 7-isoquinolyl group, 8-isoquinolyl group, 2-quinoxalinyl group, 5-quinoxalinyl group, 6-quinoxalinyl Group, 1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, 9-carbazolyl group, 1-phenanthridinyl group, 2-phenanthridinyl group, 3-phenanthridinyl group , 4-phenanthridinyl group, 6-phenanthridinyl group, 7-phenanthridinyl group, 8-phenanthridinyl group, 9 Phenanthridinyl group, 10-phenanthridinyl group, 1-acridinyl group, 2-acridinyl group, 3-acridinyl group, 4-acridinyl group, 9-acridinyl group, and the like.

  The group having an amino group represented by R1 to R8 may be any of an alkylamino group, an arylamino group, an aralkylamino group, and the like. These preferably have an aliphatic hydrocarbon group having 1 to 6 carbon atoms and / or an aromatic ring group having 1 to 4 carbon atoms. Specific examples of such groups include dimethylamino group, diethylamino group, dibutylamino group, diphenylamino group, ditolylamino group, bisbiphenylylamino group, and dinaphthylamino group. In addition, the said substituent may form the condensed ring which consists of two or more substituents, Furthermore, the derivative (s) may be sufficient as it.

  Specific examples of the compound represented by the formula (7) include compounds such as the following formulas (7-1) to (7-64).

  Guest materials include, for example, styrylbenzene dyes, oxazole dyes, perylene dyes, coumarin dyes, laser dyes such as acridine dyes, anthracene derivatives, naphthacene derivatives, pentacene derivatives, chrysene derivatives, diketopyrrolopyrrole Derivatives, polyaromatic hydrocarbon materials such as pyran derivatives or styryl derivatives, pyromethene skeleton compounds or metal complexes, quinacridone derivatives, cyanomethylenepyran derivatives (DCM, DCJTB), benzothiazole compounds, benzimidazole compounds, metal chelates It can be used by appropriately selecting from fluorescent materials such as fluorinated oxinoid compounds. The doping concentration of each of these fluorescent materials is preferably 0.5% or more and 15% or less in terms of film thickness ratio. A known phosphorescent dopant having a desired emission color can also be used. Specific examples include amines having a stilbene structure, aromatic amines, perylene derivatives, coumarin derivatives, borane derivatives, pyran derivatives, iridium complexes, platinum complexes, and rhenium complexes. Of these, phosphorescent dopant materials of iridium complexes, platinum complexes and rhenium complexes are preferably used.

  Here, as the blue light emitting guest material, a compound having an emission peak in a range of about 400 nm to 490 nm is shown. Examples of such compounds include organic substances such as naphthalene derivatives, anthracene derivatives, naphthacene derivatives, styrylamine derivatives, and bis (azinyl) methene boron complexes. Of these, aminonaphthalene derivatives, aminoanthracene derivatives, aminochrysene derivatives, aminopyrene derivatives, styrylamine derivatives, and bis (azinyl) methene boron complexes are preferably used.

  The electron supply layer 14C is for transporting electrons injected from the cathode 15 to the light emitting layer 14B. Here, two layers, a first layer 14c and a second layer 14d are provided. The first layer 14c and the second layer 14d are stacked in this order from the anode 13 side. Although the film thickness of the electron supply layer 14C depends on the overall structure of the element, it is preferably, for example, 10 nm to 200 nm, and more preferably 20 nm to 180 nm.

As a material of the first layer 14c, it is preferable to use an organic material having an excellent electron transport ability. As a result, the light emitting layers 14r, 14g, and 14b that are stacked in multiple layers can emit light at the same time, thereby forming an element with little current density dependency. As such an organic material, specifically, a nitrogen-containing heterocyclic derivative having an electron mobility of 1.0 × 10 ⁻⁴ cm ² / Vs or more can be used. The upper limit of the electron mobility is not particularly limited, but about 1.0 × 10 ⁻³ cm ² / Vs can be obtained by using the following materials. Further, although the electron supply layer 14C is two layers here, it may be a single layer including only the first layer 14c.

  Specifically, it is preferable to use an arylpyridine derivative represented by the following formula (8). Thereby, the electron supply to the light emitting layer 14B is stabilized, and stable driving is compensated for with high efficiency.

（Ａｒ１は核炭素数６〜５０個の芳香族炭化水素基あるいはその誘導体である。Ｘは少なくともピリジニル基を含有する芳香族複素環基あるいはその誘導体である。ｍは１〜５の整数であり、ｎは1〜６の整数である。但し、ｍが２以上の場合にはＡｒ１はそれぞれ同一の基あるいは異なる基でもよい。ｎが２以上の場合にはＸはそれぞれ同一の基あるいは異なる基でもよい。）

(Ar1 is an aromatic hydrocarbon group having 6 to 50 nuclear carbon atoms or a derivative thereof. X is an aromatic heterocyclic group or a derivative thereof containing at least a pyridinyl group. M is an integer of 1 to 5. , N is an integer of 1 to 6. However, when m is 2 or more, Ar1 may be the same group or different groups, and when n is 2 or more, X is the same group or different groups. May be.)

  Specific examples of the arylpyridine derivative represented by the formula (8) include compounds such as the following formulas (8-1) to (8-55).

  By using the arylpyridine derivative having a high electron supply capability as described above, high electron supply efficiency is maintained even at a low driving voltage. Note that the electron supply layer 14C may contain a compound other than the arylpyridine derivative represented by the formula (1). Examples of compounds other than arylpyridine derivatives include alkali metals, alkaline earth metals, rare earth metals and their oxides, composite oxides, fluorides, carbonates, and the like.

  As a material for the second layer 14d, an organic material having an excellent electron transport ability is preferably used, and specifically, a benzimidazole derivative represented by the following formula (9) is preferably used. Thereby, the supply amount of electrons to the light emitting layer 14B is stabilized, and stable driving is compensated for with high efficiency.

（Ａ１およびＡ２は、各々独立して水素原子、炭素数６０個以下のアリール基、炭素数６０個以下の複素環基、炭素数１〜２０個のアルキル基または炭素数１〜２０の個アルコキシ基あるいはそれらの誘導体である。Ｂは２価のパラフェニレン基であり、Ａｒ２は２，６位においてパラフェニレン基に結合されたアントラセンまたはその誘導体である。）

(A1 and A2 are each independently a hydrogen atom, an aryl group having 60 or less carbon atoms, a heterocyclic group having 60 or less carbon atoms, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. Group B or a derivative thereof, B is a divalent paraphenylene group, and Ar2 is anthracene or a derivative thereof bonded to the paraphenylene group at the 2,6-positions.)

  Specific examples of the benzimidazole derivative represented by the formula (9) include compounds such as the following formulas (9-1) to (9-42). HAr corresponds to a benzimidazole skeleton including A1 and A2 in the formula (9), and L corresponds to B in the formula (9). Ar3 corresponds to Ar2 in Formula (9), and binds to B in the order of Ar1 and Ar2.

  The cathode 15 is made of, for example, a material having a thickness of 2 nm to 15 nm, good light transmittance, and a small work function. The cathode 15 may be a single layer, but here has a structure in which, for example, the first layer 15A and the second layer 15B are stacked in this order from the anode 13 side.

The first layer 15A is preferably formed of a material having a small work function and good light transmittance. Specifically, for example, _{Li 2 O, Cs 2 Co 3} , Cs 2 SO 4, MgF, alkali metal oxides such as LiF and CaF _2, alkali metal fluorides, alkaline earth metal oxides, alkaline earth fluorides Is mentioned. The second layer 15B is made of a material having light transmissivity such as a thin MgAg electrode and a Ca electrode and having good conductivity.

  The first layer 15A and the second layer 15B are formed by a technique such as a vacuum deposition method, a sputtering method, or a plasma CVD method. When the driving method of the display device configured using the organic electroluminescent element is an active matrix method, the cathode 15 is insulated from the anode 13 by the partition wall 16 and the organic layer 14 that cover the periphery of the anode 13. In this state, a solid film may be formed on the substrate 12 and used as a common electrode for each pixel.

  The cathode 15 may be a mixed layer containing an organic light emitting material such as an aluminum quinoline complex, a styrylamine derivative, or a phthalocyanine derivative. In this case, a layer having optical transparency such as MgAg may be additionally provided as a third layer (not shown). Needless to say, the cathode 15 is not limited to the laminated structure as described above, and an optimum combination and laminated structure may be taken according to the structure of the device to be manufactured. For example, the cathode 15 of the present embodiment includes an inorganic layer (first layer 15A) that promotes functional separation of each electrode layer, that is, injection of electrons into the organic layer 14, and an inorganic layer (second layer 15B) that controls the electrode. Is a laminated structure in which However, the inorganic layer that promotes electron injection into the organic layer 14 may also serve as the inorganic layer that controls the electrode, and these layers may be configured as a single layer structure. Moreover, it is good also as a laminated structure which formed transparent electrodes, such as ITO, on this single layer structure.

  Further, when the organic electroluminescent element 11 has a cavity structure, it is preferable to use a transflective material for the cathode 15. As a result, emitted light that has been subjected to multiple interference between the light reflecting surface on the anode 13 side and the light reflecting surface on the cathode 15 side is extracted from the cathode 15 side. In this case, the optical distance between the light reflecting surface on the anode 13 side and the light reflecting surface on the cathode 15 side is defined by the wavelength of light to be extracted, and the film thickness of each layer is set so as to satisfy this optical distance. Suppose that it is done. In such a top emission type organic electroluminescence device, it is possible to improve the light extraction efficiency to the outside and control the emission spectrum by positively using this cavity structure.

(Display device)
FIG. 2 shows a configuration of the display device 10 including the organic electroluminescent element 11 (red organic electroluminescent element 11R, green organic electroluminescent element 11G, blue organic electroluminescent element 11B) of the present embodiment. The display device 10 is used as an organic EL television device or the like. For example, a plurality of organic electroluminescent elements 11 are arranged in a matrix as a display region 110 on a substrate 12. Around the display area 110, a signal line driving circuit 120 and a scanning line driving circuit 130, which are drivers for displaying images, are provided. A combination of adjacent organic electroluminescent elements 11 constitutes one pixel.

  A pixel drive circuit 140 is provided in the display area 110. FIG. 3 illustrates an example of the pixel driving circuit 140. The pixel drive circuit 140 is an active drive circuit formed below the anode 13. That is, the pixel drive circuit 140 includes a drive transistor Tr1 and a write transistor Tr2, a capacitor (holding capacitor) Cs between the transistors Tr1 and Tr2, a first power supply line (Vcc), and a second power supply line (GND). ), The organic electroluminescent element 11 (11R, 11G, 11B) connected in series to the driving transistor Tr1. The drive transistor Tr1 and the write transistor Tr2 are configured by a general thin film transistor (TFT), and the configuration may be, for example, an inverted staggered structure (so-called bottom gate type) or a staggered structure (top gate type). There is no particular limitation.

  In the pixel driving circuit 140, a plurality of signal lines 120A are arranged in the column direction, and a plurality of scanning lines 130A are arranged in the row direction. The intersection of each signal line 120A and each scanning line 130A corresponds to one of the organic electroluminescent elements 11 (subpixel). Each signal line 120A is connected to the signal line drive circuit 120, and an image signal is supplied from the signal line drive circuit 120 to the source electrode of the write transistor Tr2 via the signal line 120A. Each scanning line 130A is connected to the scanning line driving circuit 130, and a scanning signal is sequentially supplied from the scanning line driving circuit 130 to the gate electrode of the writing transistor Tr2 via the scanning line 130A.

FIG. 4 illustrates a part of a cross-sectional configuration of the display region 110 illustrated in FIG. Each of the organic electroluminescent elements 11 (11R, 11G, and 11B) has a driving transistor Tr1 and a planarization insulating film (not shown) of the pixel driving circuit 140 between the substrate 12 and the substrate 12 as described above. The anode 13, the partition 16, the organic layer 14 including the light emitting layer 14 </ b> B, and the cathode 15 are stacked in this order. Furthermore, the organic electroluminescent element 11 is covered with a protective layer 20, and further, a sealing layer 20 made of glass or the like is provided on the protective layer 20 with an adhesive layer (not shown) such as a thermosetting resin or an ultraviolet curable resin interposed therebetween. The substrate 30 is sealed by being bonded over the entire surface. The protective layer 20 includes a silicon nitride (typically Si ₃ N ₄ ) film, a silicon oxide (typically SiO ₂ ) film, a silicon nitride oxide (SiNxOy: composition ratio X> Y) film, and an oxynitridation A silicon (SiOxNy: composition ratio X> Y) film, a thin film mainly composed of carbon such as DLC (Diamond like Carbon), a CN (Carbon Nanotube) film, or the like is used. These films preferably have a single layer structure or a stacked structure. In particular, the protective layer 20 made of nitride has a dense film quality and has an extremely high blocking effect against moisture, oxygen, and other impurities that adversely affect the organic electroluminescent element 11.

The protective layer 20 has a thickness of 2 to 3 μm, for example, and may be made of either an insulating material or a conductive material. As the insulating material, an inorganic amorphous insulating material such as amorphous silicon (α-Si), amorphous silicon carbide (α-SiC), amorphous silicon nitride (α-Si _1-x N _x ), amorphous carbon (α -C) is preferred. Such an inorganic amorphous insulating material does not constitute grains, and thus has low water permeability and becomes a good protective film.

  The sealing substrate 30 is located on the cathode 15 side of the organic electroluminescent element 11 and seals the organic electroluminescent element 11 together with an adhesive layer (not shown). The sealing substrate 30 is made of a material such as glass that is transparent to the light generated by the organic electroluminescent element 11. The sealing substrate 30 is provided with, for example, a color filter and a light-shielding film (not shown) as a black matrix, and takes out the light generated in the organic electroluminescent element 11 and each organic electroluminescent element. The external light reflected in the wiring between 11 is absorbed and the contrast is improved.

  The color filter includes a red filter, a green filter, and a blue filter (all not shown), which are arranged in order. Each of the red filter, the green filter, and the blue filter is, for example, rectangular and has no gap. These red filter, green filter and blue filter are each composed of a resin mixed with a pigment, and by selecting the pigment, the light transmittance in the target red, green or blue wavelength region is high, The light transmittance in the wavelength range is adjusted to be low. A corresponding color filter is provided on each of the organic electroluminescent elements 11R, 11G, and 11B.

The light-shielding film is formed of, for example, a black resin film having an optical density of 1 or more mixed with a black colorant, or a thin film filter using thin film interference. Of these, a black resin film is preferable because it can be formed inexpensively and easily. The thin film filter is formed by, for example, laminating one or more thin films made of metal, metal nitride, or metal oxide, and attenuating light by utilizing interference of the thin film. Specific examples of the thin film filter include those in which Cr and chromium oxide (III) (Cr ₂ O ₃ ) are alternately laminated.

  Here, each layer from the anode 13 to the cathode 15 constituting the organic electroluminescent device 11 is formed by vacuum deposition, ion beam (EB), molecular beam epitaxy (MBE), sputtering, OVPD (Organic Vapor Phase). It can be formed by a dry process such as a deposition method.

  Further, in addition to the above methods, the organic layer 14 is applied by a laser transfer method, a spin coating method, a dipping method, a doctor blade method, a discharge coating method, a spray coating method, an ink jet method, an offset printing method, a letterpress printing method. , Intaglio printing method, screen printing method, microgravure coating method and other wet process can be used. Depending on the nature of each organic layer and each member, dry process and wet process can be used together I do not care.

  In the display device 10, a scanning signal is supplied to each pixel from the scanning line driving circuit 130 via the gate electrode of the writing transistor Tr2, and an image signal is held from the signal line driving circuit 120 via the writing transistor Tr2. The capacitance Cs is held. That is, the driving transistor Tr1 is controlled to be turned on / off according to the signal held in the holding capacitor Cs, whereby the driving current Id is injected into the organic electroluminescent element 11, and the holes and electrons are recombined to emit light. Occur. This light is transmitted through the anode 13 and the substrate 12 in the case of bottom emission (bottom emission), and in the case of top emission (top emission), the cathode 15, a color filter (not shown), and the sealing substrate 30. Is taken out through.

  Conventionally used organic electroluminescent elements have a structure in which, for example, a light emitting layer showing red to yellow is formed on the anode side, and a blue light emitting layer is laminated on the cathode side. In the organic electroluminescence device having such a configuration, in order to obtain white light with high color purity, for example, the thickness of the light emitting layer showing red to yellow is reduced (for example, 1 to 2 nm) or the doping concentration is reduced. The method was used. However, as described above, the thickness of the light emitting layer is very thin, and is almost the same as the molecular size used in the light emitting layer, so that it is very difficult to adjust the color purity by controlling the film thickness.

  In addition, as described above, since the organic electroluminescent element has a diode characteristic, the current density changes greatly with respect to a change in voltage. For example, in a constant current driving test, an increase in the resistance component in the organic electroluminescent element causes a drive voltage increase of usually about 0.2 to 1 V in about several hours. When the organic electroluminescence device is driven by a constant voltage driving circuit, this voltage change corresponds to a change of 10 to 50% only with the current deterioration component. Furthermore, since the luminance deterioration component is added to the current deterioration as the driving deterioration of the element, it is difficult to select a low-cost constant voltage driving circuit for driving the organic electroluminescence element, and a higher-cost constant current driving circuit is required. It was necessary to use it.

On the other hand, in this embodiment, the electron mobility is 1.0 × 10 ⁻⁴ cm ² / Vs on the light emitting layer 14B including the light emitting layers 14r, 14b, and 14g of different colors such as red, green, and blue. An electron supply layer 14C using the above nitrogen-containing heterocyclic compound is provided. This makes it possible to adjust the hole and electron carrier balance in each light emitting layer.

  As described above, the organic electroluminescent element 11 and the display device 10 including the organic electroluminescent element 11 according to the present embodiment include a plurality of light emitting layers 14r that contain two or more kinds of host materials including at least an anthracene derivative and exhibit different emission colors. , 14b, and 14g, an electron supply layer containing a nitrogen-containing heterocyclic compound having a high electron mobility is provided on the cathode 15 side. For this reason, the injection efficiency of electrons into each light emitting layer is improved, and the carrier balance is adjusted. As a result, a plurality of light emitting layers of different colors provided in the organic electroluminescent element 11 emit light uniformly, and color purity is improved. In addition, since changes in the exciton distribution are suppressed, changes in chromaticity due to changes in current density can be suppressed. Furthermore, since excitation of layers other than the light emitting layer 14B can be suppressed, generation of deterioration factors in the organic layer 14 is reduced. This makes it possible to select a constant voltage driving circuit with a constant current-voltage characteristic, that is, an increase in driving voltage and a low cost. That is, it is possible to manufacture a display device 10 that is low in cost and highly reliable with little change in chromaticity from low luminance to high luminance.

  Hereinafter, the second embodiment and the third embodiment will be described. The same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

(Second Embodiment)
FIG. 5 illustrates a part of a cross-sectional configuration of the display device 20 including the organic electroluminescent element 21 according to the second embodiment. Similar to the first embodiment, the organic electroluminescent element 21 has a configuration in which an anode 13, an organic layer 24, and a cathode 15 are stacked in this order on a substrate 12. This organic electroluminescent element 21 is different from the first embodiment in that three electron supply layers 24C are laminated.

  Specifically, the third layer 24e, the first layer 24c, and the second layer 24d are stacked in this order from the anode 13 side. The first layer 24c and the second layer 24d have the same configuration and materials as the first layer 14c and the second layer 14d described in the first embodiment.

  As a material for the third layer 24e, it is preferable to use an organic material having an excellent electron transport ability and a high charge balance ability. Thereby, the transport efficiency of electrons to the light emitting layer 14B, in particular, the red light emitting layer 14r and the green light emitting layer 14g can be increased. Specifically, it is preferable to use a dibenzimidazole derivative represented by the following formula (10) as such an organic material.

（Ｙ１〜Ｙ８は、各々独立して炭素数６〜６０個のアリール基、アルケニル基、ピリジル基、キノリル基、炭素数１〜２０個のアルキル基、炭素数１〜２０個のアルコキシ基、炭素数５〜６０個の脂肪族環基または炭素数５〜６０個以下の複素環基あるいはそれらの誘導体である。なお、Ｙ７およびＹ８は連結基を介して環状構造を形成してもよい。）

(Y1 to Y8 are each independently an aryl group having 6 to 60 carbon atoms, alkenyl group, pyridyl group, quinolyl group, alkyl group having 1 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, carbon An aliphatic cyclic group having 5 to 60 carbon atoms, a heterocyclic group having 5 to 60 carbon atoms or a derivative thereof, and Y7 and Y8 may form a cyclic structure via a linking group.

  Specific examples of the dibenzimidazole derivative represented by the formula (10) include compounds such as the following formulas (10-1) to (10-21).

  Although the electron supply layer 24C has three layers here, it may have a two-layer structure including the third layer 24e and the first layer 24c as in the display device 20A shown in FIG.

  In the organic electroluminescent element 21 (display devices 20 and 20A) of the present embodiment, the same material as that of the first layer 14c and the second layer 14d described in the first embodiment is used as the electron supply layer 24C. In addition to the formed first layer 24c and second layer 24d, a third layer 24e containing the dibenzimidazole derivative represented by the above formula (10) is provided between the light emitting layer 24B and the first layer 24c. . That is, the electron supply layer 24C has a three-layer structure in which the third layer 24e, the first layer 24c, and the second layer 24d are sequentially stacked from the anode 13 side. Thereby, the balance of the charge supplied to the light emitting layer 24B can be adjusted better than the organic electroluminescent element 11 of the first embodiment, and both high efficiency and long life can be achieved. Is possible.

(Third embodiment)
FIG. 7A illustrates a cross-sectional configuration of the organic electroluminescent element 31 according to the third embodiment. Similar to the first embodiment, the organic electroluminescent element 31 has a configuration in which an anode 13, an organic layer 34, and a cathode 15 are stacked in this order on a substrate 12. This organic electroluminescent element 21 is different from the first embodiment in that it has a tandem structure in which two organic layers 34 (first organic layer 34-1 and second organic layer 34-2) are stacked. .

  Specifically, for example, the first organic layer 34-1 and the second organic layer 34-2 having the same configuration as that of the organic layer 14 described in the first embodiment include the electron supply layer 17A and the hole. It is sandwiched between charge generation layers 17 having a structure in which an injection layer 17B is laminated.

  The electron supply layer 17A is provided on the anode 13 side and supplies electrons to the light emitting layer 34B1 on the first organic layer 34-1 side. Examples of the material for the electron supply layer 17A include electron donating metals such as alkali metals, alkaline earth metals, and rare earth metals, or compounds thereof. Specifically, for example, Alq3 doped with magnesium (Mg) can be used. Further, the electron supply layer 17A may be a mixed layer in which an organic material is added in addition to the electron donating metal. Organic materials that can be added to the electron supply layer 17A are, for example, the materials of the formulas (8-1) to (8-55) and the second layer 14d shown as the materials of the first layer 14c of the electron supply layer 24C described above. Examples of the formula (9-1) to the formula (9-32) are given.

  The hole injection layer 17B is provided on the cathode 15 side and injects holes into the light emitting layer 34B2 on the second organic layer 34-2 side. Specifically, the hole injection layer 17B extracts electrons from the second organic layer 34-2 side, and supplies electrons to the first organic layer 34-1 side via the electron supply layer 17A. Holes generated by the extraction of electrons are supplied to the light emitting layer 34B2 of the second organic layer 34-2. As the material of the hole injection layer 17B, a compound having a LUMO level greater than 4.5 eV is preferable. Specifically, the compound may be hexanitrile azatriphenylene represented by the above formula (2-1) or the following formula (11). The indicated compounds can be used.

Note that the charge generation layer 17 has an electron injecting property between the electron supply layer 17A and the electron supply layer 34C1 of the first organic layer 34-1, as in the organic electroluminescent element 31A shown in FIG. 7B. An electron injection layer 17C made of a material may be provided. As a material for the electron injection layer 17C, for example, lithium oxide (LiO ₂ ), cesium carbonate (CsCO ₃ ), or a mixture of these oxides and composite oxides can be used. The electron injection layer 17C is not limited to these materials. For example, alkaline earth metals such as calcium (Ca) and barium (Ba), alkali metals such as Li and Cs, indium (In) and Mg are used. A metal having a small work function, or an oxide or composite oxide thereof may be used. Furthermore, a mixture or alloy in which two or more of these oxides and composite oxides are combined to improve safety may be used.

  In the organic electroluminescent elements 31 and 31A of the present embodiment, the organic layer 34 has a tandem structure in which two organic layers 34 (first organic layer 34-1 and second organic layer 34-3) are stacked. In addition to the effect of the first embodiment, the luminous efficiency is further improved.

  Although the case where two organic layers 34 are stacked is shown here, the present invention is not limited to this, and three or more layers may be stacked. Increasing the number of stacked layers can further improve the light emission efficiency. The theoretical luminous efficiency in the case where two organic layers 34 are stacked as in the organic electroluminescent device 21 of the present embodiment has a current efficiency cd / A doubled and three layers without changing lm / W. In the case of lamination, it becomes three times.

(Modules and application examples)
Hereinafter, application examples of the organic EL display device described in the above embodiment will be described. The organic EL display device according to the embodiment described above is a video signal input from the outside or a video signal generated inside, such as a television device, a digital camera, a notebook personal computer, a mobile terminal device such as a mobile phone, or a video camera. The present invention can be applied to display devices of electronic devices in various fields that display as images or videos.

(module)
The display device of the above embodiment is incorporated into various electronic devices such as application examples 1 to 5 described later as a module as shown in FIG. In this module, for example, the protective layer 20 and the sealing substrate 3 “the region 210 exposed from 0” are provided on one side of the substrate 11, and the signal line driving circuit 120 and the scanning line driving circuit 130 are provided in the exposed region 210. The wiring is extended to form an external connection terminal (not shown), which is provided with a flexible printed circuit (FPC) 220 for signal input / output. Also good.

(Application example 1)
FIG. 9 illustrates an appearance of a television device to which the display device of the above embodiment is applied. This television apparatus has, for example, a video display screen unit 300 including a front panel 310 and a filter glass 320, and the video display screen unit 300 is configured by the display device according to the above embodiment.

(Application example 2)
FIG. 10 shows the appearance of a digital camera to which the display device of the above embodiment is applied. The digital camera includes, for example, a flash light emitting unit 410, a display unit 420, a menu switch 430, and a shutter button 440, and the display unit 420 is configured by the display device according to the above embodiment. .

(Application example 3)
FIG. 11 shows the appearance of a notebook personal computer to which the display device of the above embodiment is applied. The notebook personal computer has, for example, a main body 510, a keyboard 520 for inputting characters and the like, and a display unit 530 for displaying an image. The display unit 530 is a display device according to the above embodiment. It is comprised by.

(Application example 4)
FIG. 12 shows the appearance of a video camera to which the display device of the above embodiment is applied. This video camera has, for example, a main body 610, a subject photographing lens 620 provided on the front side surface of the main body 610, a start / stop switch 630 at the time of photographing, and a display 640. Reference numeral 640 denotes the display device according to the above embodiment.

(Application example 5)
FIG. 13 illustrates an appearance of a mobile phone to which the display device of the above embodiment is applied. For example, the mobile phone is obtained by connecting an upper housing 710 and a lower housing 720 with a connecting portion (hinge portion) 730, and includes a display 740, a sub-display 750, a picture light 7630, and a camera 770. Yes. The display 740 or the sub-display 750 is configured by the display device according to the above embodiment.

Example 1
Next, Example 1 of the present invention will be described. Example 1 and Comparative Example 1 correspond to the first embodiment. This organic electroluminescent element 11 resonates between the anode 13 and the cathode 15 with the light emitted when the holes injected from the anode 13 and the electrons injected from the cathode 15 recombine in the light emitting layer 14C. This is a top emission type organic electroluminescence device having a resonator structure that is taken out from the cathode 15 side opposite to the substrate 12. This also applies to Example 2 described later.

First, an Al layer having a thickness of 200 nm is formed as an anode 13 on a substrate 12 made of a glass plate of 30 mm × 30 mm, and then an insulating film (not shown) is formed except for a light emitting region of 2 mm × 2 mm by SiO ₂ vapor deposition. A cell for an organic electroluminescent element masked with () was prepared. Subsequently, on the anode 13, hexanitrile azatriphenylene represented by the formula (2-1) was formed as the hole supply layer 14 a with a deposition rate of 0.2 to 0.4 nm / sec and a film thickness of 10 nm, and then holes were formed. As the transport layer 14b, the compound represented by the formula (12) was formed at a deposition rate of 0.2 to 0.4 nm / sec and a film thickness of 30 nm by a vacuum deposition method.

  Next, as the light emitting layer 14B, a red light emitting layer 14r, a blue light emitting layer 14b, and a green light emitting layer 14g were appropriately laminated according to the charge transporting ability of each light emitting layer. A light emitting layer separation layer was provided between the red light emitting layer 14r and the upper light emitting layer (blue light emitting layer 14b and green light emitting layer 14g). Each film thickness is 10 nm here. Specifically, in the red light emitting layer 14r, for example, a compound represented by the formula (6-1) as a host material and a compound represented by the formula (13) as a guest material are formed so as to have a doping concentration of 1%. The light emitting layer separation layer was formed using the compound represented by the formula (4-42) and had a thickness of 5 nm. Subsequently, in the blue light emitting layer 14b, for example, the compound represented by the formula (7-46) is used as the host material, and the fluorescent material represented by the formula (15) is used as the guest material so that the doping concentration is 5%. Formed. Next, in the green light emitting layer 14g, the compound represented by the formula (7-46) is used as the host material, for example, similarly to the blue light emitting layer 14b, and the compound represented by the formula (16) is doped as the guest material, for example. It was formed to be 5%. Alternatively, the phosphor material shown in the formula (17) is formed on the host material shown in the formula (19) so as to have a doping concentration of 5%, thereby forming the light emitting layer 14B. In addition to the compounds shown in the embodiment, compounds represented by the following formulas (18) to (20) were used as host materials for the red light emitting layer 14r, the blue light emitting layer 14b, and the green light emitting layer 14g.

  Next, the electron supply layer 14C was formed on the light emitting layer 14B using, for example, the compound represented by the formula (8-18) (Examples 1-1 and 1-2). Further, an electron supply layer 14C composed of two layers in which a second layer 14d formed using the compound represented by the formula (9-39) was further laminated on the first layer 14c composed of the formula (8-18) was formed. (Example 1-4). Further, an electron supply layer composed of three layers in which a third layer 24e composed of the formula (10-1), a first layer 24c composed of the formula (8-36), and a second layer 24d composed of the formula (9-10) are laminated. 24C was formed (Example 1-7).

  Subsequently, after forming the organic layer 14, as the first layer 15a of the cathode 15, LiF is formed with a film thickness of about 0.3 nm (deposition rate˜0.01 nm / sec) by vacuum evaporation, and then the second layer 15a. As the layer 15b, MgAg was formed to a thickness of 10 nm by a vacuum deposition method, and the cathode 15 having a two-layer structure was provided. In this case, the surface of the second layer 15b on the organic layer 14 side is the second end surface P2 of the resonator structure. The organic electroluminescent element 11 was produced as described above.

(Example 2)
Example 2 and Comparative Example 2 correspond to the third embodiment in which the organic layer 34 has a tandem structure. First, an Al layer having a thickness of 200 nm is formed as an anode 13 on a substrate 12 made of a glass plate of 30 mm × 30 mm, and then an insulating film (not shown) is formed except for a light emitting region of 2 mm × 2 mm by SiO ₂ vapor deposition. A cell for an organic electroluminescent element masked with () was prepared. Subsequently, on the anode 13, hexanitrile azatriphenylene represented by the formula (2-1) was formed as the hole supply layer 14 a with a deposition rate of 0.2 to 0.4 nm / sec and a film thickness of 10 nm, and then holes were formed. As the transport layer 14b, the compound represented by Formula 10 was formed by a vacuum deposition method with a deposition rate of 0.2 to 0.4 nm / sec and a film thickness of 30 nm.

  Next, a blue light-emitting layer having a thickness of 10 nm was formed as the first light-emitting layer 34B1. Specifically, for example, in a blue light emitting layer, a compound represented by the formula (7-55) is used as a host material, and a compound represented by the formula (15) is used as a guest material. An electron supply layer 34C1 was formed to a thickness of 40 nm on the layer 44B1 using, for example, a compound represented by Formula (8-54).

  After forming the first organic layer 34-1 as described above, the charge generation layer 17 was formed on the electron supply layer 34C1. Specifically, the LiF layer is 0.5 nm thick as the electron injection layer 17C, the Alq3 + Mg (10%) layer is 10 nm thick as the electron supply layer 17A, and the hexonitrile azatriphenylene layer is 10 nm thick as the hole injection layer 17B. Were sequentially deposited.

  Next, after the hole supply layer 34A2 was formed using the same method, a red light emitting layer and a green light emitting layer were laminated in this order as the light emitting layer 34B2. In addition, the light emitting layer separation layer was provided between the red light emitting layer and the blue light emitting layer. Each film thickness is 10 nm here. Specifically, in the red light emitting layer, for example, after forming the compound represented by the formula (6-1) as the host material and the compound represented by the formula (13) as the guest material so as to have a doping concentration of 1%, A light emitting layer separation layer was formed with a thickness of 5 nm using the compound represented by the formula (4-42).

  Subsequently, in the green light emitting layer, for example, the compound shown in the formula (7-55) is used as the host material similarly to the blue light emitting layer 34b, and the compound shown in the formula (16) is used as the guest material. It was formed to have a thickness of 5% and a thickness of 10 nm. Alternatively, the light emitting layer 34B2 was formed by using the compound represented by the formula (19) and the phosphorescent material represented by the formula (17) so as to have a doping concentration of 15% and a thickness of 10 nm. Next, an electron supply layer 34C2 was formed on the light emitting layer 34B2 by using the same method to obtain a second organic layer 34-2.

  Finally, using the same method as in Example 1, LiF was deposited on the organic layer 34-2 as the first layer 15a of the cathode 15 by about 0.3 nm (deposition rate: 0.01 nm / sec) by vacuum evaporation. Then, MgAg was formed as a second layer 15b with a thickness of 10 nm by a vacuum deposition method.

In an organic electroluminescent device manufactured as described above, the voltage (V) at a current density of chromaticity and 10MAcm ^-2 at a current density of 1 mA cm ^-2 and 100MAcm ^-2, were measured current efficiency (cd / A). Further, the driving voltage after 1000 hours of constant current driving at 50 ° C. and 30 mAcm ⁻² was measured, and the difference from the initial voltage was calculated.

  Tables 1 and 2 list materials and film thicknesses used as the light emitting layers 14B, 24B, 34B1, and 34B2 and the electron supply layers 14C, 24C, and 34C of Examples 1 and 2 and Comparative Examples 1 and 2. Tables 3 and 4 list measurement results of Examples 1 and 2 and Comparative Examples 1 and 2.

From Tables 3 and 4, by using a hole transporting host material for one of the light emitting layers 14B (24B, 34B1, 34B2) and using a compound having an electron mobility of 1.0 × 10 ⁻⁴ cm ² / Vs or more. It has been found that chromaticity changes at low and high current densities are reduced. Further, the voltage at a current density of 10 mAcm ⁻² is also kept low, and the luminous efficiency is high. In particular, the change with time of the drive voltage is suppressed. Moreover, the remarkable improvement was seen in Example 1-7 and Example 1-8 which laminated | stacked the dibenzimidazole compound.

  On the other hand, such a result is not obtained in the comparative example. This is because in Comparative Example 1-1, Alq3 having a low electron mobility, which has been conventionally used, was used for the electron supply layer, so that the light emitting region when the electric field was applied remained in the electron supply layer, and the current density was low. This is probably because three-color emission cannot be obtained. Further, it is considered that the chromaticity in Comparative Example 1-2 is that the same host material is used for the light emitting layers of the respective colors, so that the light emitting regions are concentrated in one place, and three-color light emission cannot be obtained. In Comparative Examples 1-3 and 1-4, although an arylpyridine compound having a high mobility was used as the electron transport layer, excitons were concentrated in one place by using no anthracene compound in the light-emitting layer, and three-color light emission was obtained. It is thought that it was not done. Further, since the exciton balance stability during driving cannot be obtained, it is considered that a change in chromaticity, a decrease in light emission efficiency, and an increase in driving voltage occurred. Further, in Comparative Examples 2-1 and 2-2, since Alq3 having a low electron mobility was used, it is considered that a significant increase in driving voltage and a change in chromaticity due to current density dependency occurred.

  The present invention has been described with reference to the first to third embodiments and examples. However, the present invention is not limited to the above-described embodiments and the like, and various modifications can be made.

  For example, the material and thickness of each layer described in the above embodiment and the like, or the film formation method and film formation conditions are not limited, and other materials and thicknesses may be used, or other film formation methods and film formation may be performed. It is good also as film | membrane conditions.

  Moreover, in the said embodiment etc., although the structure of the organic electroluminescent element 11 (21, 31) was specifically mentioned and demonstrated, it is not necessary to provide all the layers, and also provided with another layer. Also good.

  Further, in the above-described embodiments and the like, the case of an active matrix display device has been described, but the present invention can also be applied to a passive matrix display device. Furthermore, the configuration of the pixel driving circuit for active matrix driving is not limited to that described in the above embodiment, and a capacitor or a transistor may be added as necessary. In that case, a necessary driving circuit may be added in addition to the signal line driving circuit 120 and the scanning line driving circuit 130 described above in accordance with the change of the pixel driving circuit.

  In the organic electroluminescent element 11 (21, 31) described in the above embodiment, the color purity of the extracted light is obtained by adopting a resonator structure in which the emitted light is resonated and extracted between the anode 13 and the cathode 15. And the intensity of extracted light near the center wavelength of resonance can be improved. In this case, the reflective end face of the anode 13 on the light emitting layer 14B side is the first end P1 (not shown), the reflective end face of the cathode 15 on the light emitting layer 14B side is the second end P2 (not shown), and the organic layer 14 is In the case of a resonator structure in which the light generated in the light emitting layer 14B is resonated and extracted from the second end portion P2 side as the resonance portion, it is between the first end portion P1 and the second end portion P2 of the resonator. The optical distance L is set so as to satisfy the following formula (1). In practice, the optical distance L is preferably selected so as to be a positive minimum value satisfying the expression (1).

In the above formula (1), L is the optical distance between the first end P1 and the second end P2, and Φ is the phase shift Φ ₁ of the reflected light generated at the first end P1 and the second end. The sum (Φ = Φ ₁ + Φ ₂ ) (rad) of the phase shift Φ ₂ of the reflected light generated at P 2, λ is the peak wavelength of the spectrum of light desired to be extracted from the second end P 2 side, and m is positive when L is positive Each represents an integer. In the formula (1), L and λ may have the same unit. For example, the unit is (nm).

In the organic light emitting device 11, the optical distance L ₁ between the maximum light emission position of the light emitting layer 14B and the first end P1 satisfies the following formula (2), and the maximum light emission position and the second end P2 The optical distance L2 between them is adjusted so as to satisfy the following formula (3). Here, the maximum light emission position refers to a position having the highest light emission intensity in the light emission region. For example, in the case where light is emitted from both the anode 13 side and the cathode 15 side of the light emitting layer 14B, the interface having the larger emission intensity is used.

In the above formula (2), tL ₁ is the optical theoretical distance between the first end P1 and the maximum light emission position, a ₁ is the correction amount based on the light emission distribution in the light emitting layer 14B, and λ is the spectrum of the light to be extracted. , Φ ₁ represents the phase shift (rad) of the reflected light generated at the first end P1, and m ₁ represents 0 or an integer.

In the above formula (3), tL ₂ is the optical theoretical distance between the second end portion P2 and the maximum light emission position 13E, a ₂ is the correction amount based on the light emission distribution in the light emitting layer 14B, and λ is the light to be extracted. The peak wavelength of the spectrum, Φ ₂ represents the phase shift (rad) of the reflected light generated at the second end P2, and m ₂ represents 0 or an integer.

  The above formula (2) indicates that when light directed toward the anode 13 out of the light generated in the light emitting layer 14B is reflected by the first end P1 and returned, the phase of the return light and the phase at the time of light emission Is the same, and is in a relationship of strengthening with the light emitted toward the cathode 15 among the emitted light. Further, when the light traveling toward the cathode 15 out of the light generated in the light emitting layer 14B is reflected and returned by the second end portion P2, the expression (3) indicates the phase of the return light and the phase during light emission. In order to have a strengthening relationship with the light emitted toward the anode 13.

In the organic electroluminescent element 11 of the present embodiment, the electron transport layer 14d is formed thicker than the total film thickness of the hole supply layer 14A, so that m ₁ > m ₂ in the above formulas (2) and (3). It is possible to design as follows. Thereby, the light extraction efficiency can be increased.

The optical theory distance tL ₂ of formula (2) optical theory distance tL ₁ and Equation (3) of, when considering that there is no spread in the light-emitting area, the first end portion P1 or the second end portion P2 This is a theoretical value in which the amount of phase change at the time and the amount of phase change due to progress cancel each other, and the phase of the return light and the phase at the time of light emission are the same. However, since the light emission part is usually wide, correction amounts a ₁ and a ₂ based on the light emission distribution are added in the expressions (2) and (3).

Although the correction amounts a ₁ and a ₂ vary depending on the light emission distribution, the maximum light emission position is on the cathode 15 side of the light emitting layer 14B, and the light emission distribution extends from the maximum light emission position to the anode 13 side, or the maximum light emission position is light emission. When it is on the anode 13 side of the layer 14B and the light emission distribution spreads from the maximum light emission position to the cathode 15 side, it can be obtained, for example, by the following formula (4).

  In the formula (4), b is a value within the range of 2n ≦ b ≦ 6n when the light emission distribution in the light emitting layer 14B extends from the maximum light emission position to the anode 13, and the direction from the maximum light emission position to the cathode 15 Is a value in the range of −6n ≦ b ≦ −2n, s is a physical property value (1 / e attenuation distance) regarding the light emission distribution in the light emitting layer 13C, and n is a peak of the spectrum of light to be extracted. It is an average refractive index between the first end P1 and the second end P2 at the wavelength λ.

  In the case of a top-surface light emitting device configured with a resonator structure in which emitted light is resonated and extracted between the anode 13 and the cathode 15, the cathode 15 preferably has the following configuration. For example, the second cathode 15B is configured using a semi-transmissive reflective material such as Mg—Ag, and the emitted light is resonated between the second cathode 15B and the anode 13. The second cathode 15B is made of, for example, a transparent SiNx compound, and is formed as a sealing electrode for suppressing electrode deterioration.

  Moreover, in the said embodiment etc., as organic electroluminescent element 11 (11R, 11G, 11B) and each color filter, red, green, and blue were shown as an example, However, It is not restricted to this, Yellow or white organic electric field A light emitting element and a color filter may be used. In the case of white, a color filter may not be provided.

  In the above-described embodiments and the like, the top emission organic electroluminescent element 11 (21, 31) has been described. However, the present invention is not limited to this, and an organic layer having at least a light emitting layer between an anode and a cathode. The present invention can be widely applied to organic electroluminescent elements formed by sandwiching. In other words, the cathode, organic layer, and anode are stacked in order from the substrate side, and the electrode located on the substrate side (the lower electrode as the cathode or anode) is made of a transparent material and positioned on the opposite side of the substrate. The electrode (upper electrode as a cathode or anode) is made of a reflective material, so that it can be applied to a bottom emission type (so-called transmission type) organic electroluminescence device in which light is extracted only from the lower electrode side. is there.

  Furthermore, as long as it is an organic electroluminescent element in which an organic layer is sandwiched between a pair of electrodes (anode and cathode) and an electrode between them, other components (for example, an inorganic compound layer or an inorganic component) may be included. I do not care.

  Reference numerals 11, 21, 31, organic electroluminescent elements, 12, substrate, 13, anode, 14, organic layer, 14 A, hole supply layer, 14 B, luminescent layer, 14 C, 24 C, 34 C, electron supply layer, 15, cathode, 16 ... partition wall, 17 ... connection layer, 30 ... protective layer, 40 ... substrate for sealing

Claims (19)

An organic electroluminescent device comprising an organic layer having a plurality of light emitting layers exhibiting different emission colors between an anode and a cathode,
The light emitting layer contains at least two kinds of host materials containing an anthracene derivative;
An organic electroluminescent element comprising an electron supply layer containing a nitrogen-containing heterocyclic compound and an electron mobility of 1.0 × 10 ⁻⁴ cm ² / Vs or more between the cathode and the light emitting layer. The organic electroluminescent element according to claim 1, wherein the nitrogen-containing heterocyclic compound used in the electron supply layer is a compound represented by the formula (1).

(Ar1 is an aromatic hydrocarbon group having 6 to 50 nuclear carbon atoms or a derivative thereof. X is an aromatic heterocyclic group or a derivative thereof containing at least a pyridinyl group. M is an integer of 1 to 5. , N is an integer of 1 to 6. However, when m is 2 or more, Ar1 may be the same group or different groups, and when n is 2 or more, X is the same group or different groups. May be.) The organic material according to claim 2, wherein the electron supply layer includes a first electron supply layer containing a compound represented by the formula (1) and a second electron supply layer containing a compound represented by the formula (2). Electroluminescent device.

(A1 and A2 are each independently a hydrogen atom, an aryl group having 60 or less carbon atoms, a heterocyclic group having 60 or less carbon atoms, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. Group B or a derivative thereof, B is a divalent paraphenylene group, and Ar2 is anthracene or a derivative thereof bonded to the paraphenylene group at the 2,6-positions.)   The organic electroluminescence device according to claim 2, wherein the electron supply layer has a configuration in which the first electron supply layer and the second electron supply layer are stacked in this order from the anode side. The organic material according to claim 2, wherein the electron supply layer has a configuration in which a third electron supply layer containing a compound represented by the formula (3) and a first electron supply layer are stacked in this order from the anode side. Electroluminescent device.

(Y1 to Y8 are each independently an aryl group having 6 to 60 carbon atoms, alkenyl group, pyridyl group, quinolyl group, alkyl group having 1 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, carbon An aliphatic cyclic group having 5 to 60 carbon atoms, a heterocyclic group having 5 to 60 carbon atoms or a derivative thereof, and Y7 and Y8 may form a cyclic structure via a linking group.   The organic electric field according to claim 3, wherein the electron supply layer has a configuration in which the third electron supply layer, the first electron supply layer, and the second electron supply layer are stacked in this order from the anode side. Light emitting element. The organic electroluminescent element according to claim 1, wherein the anthracene derivative is a compound represented by the formula (4).

(R24 to R29 are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, a group having a carbonyl group having 20 or less carbon atoms, a group having a carbonyl ester group, an alkyl group, an alkenyl group, an alkoxyl group. Group or a derivative thereof, a group having a silyl group having 30 or less carbon atoms, a group having an aryl group, a group having a heterocyclic group, a group having an amino group, or a derivative thereof.)   The organic light emitting device according to claim 1, wherein the light emitting layer includes at least a hole transporting material as a host material.   The organic electroluminescence device according to claim 8, wherein the hole transporting material has an ionization potential of less than 5.6 eV.   The organic light emitting device according to claim 1, wherein the light emitting layer includes at least a phosphorescent material as a host material.   The organic electroluminescent element according to claim 10, wherein the phosphorescent material is a carbazole derivative or a quinoline complex derivative.   The organic electroluminescent element according to claim 8, wherein the hole transporting material is a polycyclic aromatic hydrocarbon compound having a mother skeleton of 4 to 7 ring members.   The organic electroluminescence device according to claim 13, wherein a mother skeleton of the polycyclic aromatic hydrocarbon compound is pyrene, benzopyrene, chrysene, naphthacene, benzonaphthacene, dibenzonaphthacene, perylene, or coronene. The organic electroluminescent element according to claim 12, wherein the hole transporting material is a compound represented by Formula (5).

(R1 to R8 are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a carbonyl group having 1 to 20 carbon atoms, a carbonyl ester group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms, carbon An alkenyl group having 1 to 20 carbon atoms, an alkoxyl group having 1 to 20 carbon atoms, a cyano group, a nitro group, a silyl group having 5 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, a heterocyclic group, or carbon An amino group having a number in the range of 1 to 30 or a derivative thereof.   The organic electroluminescence device according to claim 14, wherein the light-emitting layer containing the hole transporting material is a perylene derivative, a diketopyrrolopyrrole derivative, a pyromethene complex, a pyran derivative, or a styryl derivative as a guest material.   The organic electroluminescent element according to claim 1, wherein the plurality of light emitting layers are laminated in order of a red light emitting layer, a blue light emitting layer, and a green light emitting layer from the anode side.   The organic electroluminescence device according to claim 1, which has a tandem structure in which at least two organic layers are stacked via a charge generation layer.   The organic electroluminescence device according to claim 17, wherein the charge generation layer has a structure in which an electron supply layer and a hole injection layer are sequentially stacked from the anode side. Provided with a plurality of organic electroluminescent elements on the substrate,
The organic electroluminescent element is:
An organic electroluminescent device comprising an organic layer having a plurality of light emitting layers exhibiting different emission colors between an anode and a cathode,
The light emitting layer contains at least two kinds of host materials containing an anthracene derivative;
A display device comprising a nitrogen-containing heterocyclic compound and an electron supply layer having an electron mobility of 1.0 × 10 ⁻⁴ cm ² / Vs or more between the cathode and the light emitting layer.

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