JP2012222249A - Light-emitting element, light-emitting device, authentication device, and electronic appliance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting element with high efficiency and long life emitting light in a near-infrared region, and provide a light-emitting device, an authentication device, and an electronic appliance including the light-emitting element.SOLUTION: A light-emitting element includes a light-emitting layer provided between an anode and a cathode, and an electron transport layer provided between the cathode and the light-emitting layer and in contact with the light-emitting layer. The light-emitting layer contains a compound represented by the following formula (1) as a light-emitting material. The electron transport layer contains a compound having an azaindolizine skeleton and an anthracene skeleton in a molecule, as an electron transport property material.

Description

  The present invention relates to a light emitting element, a light emitting device, an authentication device, and an electronic device.

  An organic electroluminescence element (so-called organic EL element) is a light emitting element having a structure in which at least one light emitting organic layer is interposed between an anode and a cathode. In such a light emitting device, by applying an electric field between the cathode and the anode, electrons are injected into the light emitting layer from the cathode side and holes are injected from the anode side, and electrons and holes are injected into the light emitting layer. Recombination generates excitons, and when the excitons return to the ground state, the energy is emitted as light.

As such a light emitting element, one emitting light in a long wavelength region exceeding 700 nm is known (for example, see Patent Documents 1 and 2).
For example, in the light-emitting element described in Patent Documents 1 and 2, light emission is achieved by using a material in which an amine as an electron donor and a nitrile group as an electron acceptor are used as functional groups in the molecule as a dopant in the light-emitting layer. The wavelength is increased.
However, conventionally, it has not been possible to realize a highly efficient and long-life device that emits light in the near infrared region.
In addition, a highly efficient and long-life light emitting element that emits light in the near infrared region is desired to be realized as a light source for biometric authentication that authenticates an individual using biometric information such as veins and fingerprints.

JP 2000-091973 A JP 2001-110570 A

  An object of the present invention is to provide a high-efficiency and long-life light-emitting element that emits light in the near-infrared region, a light-emitting device including the light-emitting element, an authentication device, and an electronic apparatus.

Such an object is achieved by the present invention described below.
The light emitting device of the present invention comprises an anode,
A cathode,
A light emitting layer that is provided between the anode and the cathode, and emits light when energized between the anode and the cathode;
An electron transport layer provided between and in contact with the light emitting layer between the cathode and the light emitting layer, and having an electron transporting property;
The light emitting layer includes a compound represented by the following formula (1) as a light emitting material,
The electron transport layer includes a compound having an azaindolizine skeleton and an anthracene skeleton in the molecule as an electron transport material.

According to the light emitting element configured as described above, since the compound represented by the formula (1) is used as the light emitting material, it is possible to obtain light emission in a wavelength region (near infrared region) of 700 nm or more.
In addition, since a compound having an azaindolizine skeleton and an anthracene skeleton in the molecule is used as the electron transport material of the electron transport layer adjacent to the light emitting layer, it is possible to efficiently transport electrons from the electron transport layer to the light emitting layer. Can do. Therefore, the light emission efficiency of the light emitting element can be improved.

In addition, since the electron transport from the electron transport layer to the light emitting layer can be efficiently performed, the driving voltage of the light emitting element can be lowered, and accordingly, the life of the light emitting element can be extended.
Furthermore, since a compound having an azaindolizine skeleton and an anthracene skeleton in a molecule is excellent in stability (resistance) against electrons and holes, the life of the light-emitting element can also be extended in this respect.

In the light emitting device of the present invention, the electron transporting material preferably has one or two azaindolizine skeletons and anthracene skeletons in one molecule.
Thereby, the electron transport property and the electron injection property of the electron transport layer can be made excellent.
In the light-emitting element of the present invention, it is preferable that the light-emitting layer includes a host material that holds the light-emitting material.
Accordingly, the host material can recombine holes and electrons to generate excitons, and the energy of the excitons can be transferred to the light emitting material to excite the light emitting material. Therefore, the light emission efficiency of the light emitting element can be increased.

In the light emitting device of the present invention, the host material preferably includes an acene-based material.
Thereby, electrons can be efficiently transferred from the anthracene skeleton portion of the electron transporting material in the electron transporting layer to the acene-based material in the light emitting layer.
In the light emitting device of the present invention, the acene material is preferably an anthracene material.
Thereby, electrons can be efficiently delivered from the anthracene skeleton portion of the electron transport material in the electron transport layer to the anthracene material in the light emitting layer.

In the light emitting device of the present invention, the acene material is preferably a tetracene material.
Thereby, electrons can be efficiently delivered from the anthracene skeleton portion of the electron transporting material in the electron transporting layer to the tetracene-based material in the light emitting layer.
In the light emitting device of the present invention, the acene-based material is preferably composed of carbon atoms and hydrogen atoms.
Thereby, it is possible to prevent unintended interaction between the host material and the light emitting material. Therefore, the light emission efficiency of the light emitting element can be increased. In addition, the resistance of the host material to potential and holes can be increased. Therefore, the lifetime of the light emitting element can be extended.

In the light emitting device of the present invention, the host material preferably includes a quinolinolato metal complex.
Accordingly, the quinolinolato-based metal complex can recombine holes and electrons to generate excitons, and can excite the light emitting material by transferring the energy of the excitons to the light emitting material. Further, by utilizing the low carrier mobility of the quinolinolato-based metal complex, the balance between electrons and holes in the light-emitting layer can be adjusted, so that the lifetime of the light-emitting element can be extended.

The light-emitting device of the present invention includes the light-emitting element of the present invention.
Such a light emitting device can emit light in the near infrared region. Further, since the light-emitting element with high efficiency and long life is provided, the reliability is excellent.
The authentication apparatus of the present invention includes the light emitting element of the present invention.
Such an authentication apparatus can perform biometric authentication using near infrared light. Further, since the light-emitting element with high efficiency and long life is provided, the reliability is excellent.
The electronic device of the present invention includes the light emitting element of the present invention.
Since such an electronic device includes a light-emitting element with high efficiency and a long lifetime, it has excellent reliability.

It is a figure which shows typically the longitudinal cross-section of the light emitting element which concerns on embodiment of this invention. It is a longitudinal cross-sectional view which shows embodiment of the display apparatus to which the light-emitting device of this invention is applied. It is a figure which shows embodiment of the authentication apparatus of this invention. 1 is a perspective view showing a configuration of a mobile (or notebook) personal computer to which an electronic apparatus of the present invention is applied. It is a figure which shows the emission spectrum of the light emitting element in the Example (Examples 1 and 2) of this invention, and a comparative example (Comparative Examples 1 and 2). It is a figure for demonstrating the lifetime in the Example (Examples 1-3) and comparative example (comparative example 1) of this invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a light-emitting element, a light-emitting device, an authentication device, and an electronic device of the invention will be described with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view schematically showing a light emitting device according to an embodiment of the present invention. In the following description, for convenience of explanation, the upper side in FIG.
A light-emitting element (electroluminescence element) 1 shown in FIG. 1 includes an anode 3, a hole injection layer 4, a hole transport layer 5, a light-emitting layer 6, an electron transport layer 7, an electron injection layer 8, and a cathode 9 stacked in this order. It has been made. That is, in the light emitting element 1, the hole injection layer 4, the hole transport layer 5, the light emitting layer 6, the electron transport layer 7, and the electron injection layer 8 are arranged between the anode 3 and the cathode 9 from the anode 3 side to the cathode 9 side. And the laminated body 14 laminated | stacked in this order is inserted.

The entire light emitting element 1 is provided on the substrate 2 and is sealed with a sealing member 10.
In such a light emitting device 1, by applying a driving voltage to the anode 3 and the cathode 9, electrons are supplied (injected) from the cathode 9 side to the light emitting layer 6. Holes are supplied (injected) from the side. In the light emitting layer 6, holes and electrons are recombined, and excitons (excitons) are generated by the energy released upon the recombination, and energy (fluorescence or phosphorescence) is generated when the excitons return to the ground state. Is emitted (emitted). Thereby, the light emitting element 1 emits light.
In particular, the light emitting element 1 emits light in the near infrared region by using a platinum complex compound as a light emitting material of the light emitting layer 6 as described later. In the present specification, the “near infrared region” refers to a wavelength region of 700 nm to 1500 nm.

The substrate 2 supports the anode 3. Since the light-emitting element 1 of the present embodiment is configured to extract light from the substrate 2 side (bottom emission type), the substrate 2 and the anode 3 are substantially transparent (colorless transparent, colored transparent, or translucent), respectively. Has been.
Examples of the constituent material of the substrate 2 include resin materials such as polyethylene terephthalate, polyethylene naphthalate, polypropylene, cycloolefin polymer, polyamide, polyethersulfone, polymethyl methacrylate, polycarbonate, and polyarylate, quartz glass, and soda glass. Such glass materials can be used, and one or more of these can be used in combination.
Although the average thickness of such a board | substrate 2 is not specifically limited, It is preferable that it is about 0.1-30 mm, and it is more preferable that it is about 0.1-10 mm.

In the case where the light emitting element 1 is configured to extract light from the side opposite to the substrate 2 (top emission type), the substrate 2 can be either a transparent substrate or an opaque substrate.
Examples of the opaque substrate include a substrate made of a ceramic material such as alumina, an oxide film (insulating film) formed on the surface of a metal substrate such as stainless steel, and a substrate made of a resin material. It is done.
In such a light-emitting element 1, the distance between the anode 3 and the cathode 9 (that is, the average thickness of the laminate 14) is preferably 100 to 500 nm, and more preferably 100 to 300 nm. 100 to 250 nm is more preferable. Thereby, the drive voltage of the light emitting element 1 can be set within a practical range easily and reliably.

Hereinafter, each part which comprises the light emitting element 1 is demonstrated sequentially.
[anode]
The anode 3 is an electrode that injects holes into the hole transport layer 5 through a hole injection layer 4 described later. As a constituent material of the anode 3, it is preferable to use a material having a large work function and excellent conductivity.

Examples of the constituent material of the anode 3 include oxides such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), In ₃ O ₃ , SnO ₂ , Sb-containing SnO ₂ , and Al-containing ZnO, Au, Pt, and Ag. Cu, alloys containing these, and the like can be used, and one or more of these can be used in combination.
In particular, the anode 3 is preferably made of ITO. ITO is a material having transparency, a large work function, and excellent conductivity. Thereby, holes can be efficiently injected from the anode 3 into the hole injection layer 4.

Further, the surface of the anode 3 on the hole injection layer 4 side (the upper surface in FIG. 1) is preferably subjected to plasma treatment. Thereby, the chemical and mechanical stability of the joint surface between the anode 3 and the hole injection layer 4 can be enhanced. As a result, the hole injection property from the anode 3 to the hole injection layer 4 can be improved. Such plasma treatment will be described in detail in the description of the method for manufacturing the light emitting element 1 described later.
The average thickness of the anode 3 is not particularly limited, but is preferably about 10 to 200 nm, and more preferably about 50 to 150 nm.

[cathode]
On the other hand, the cathode 9 is an electrode that injects electrons into the electron transport layer 7 through an electron injection layer 8 described later. As a constituent material of the cathode 9, it is preferable to use a material having a small work function.
Examples of the constituent material of the cathode 9 include Li, Mg, Ca, Sr, La, Ce, Er, Eu, Sc, Y, Yb, Ag, Cu, Al, Cs, Rb, and alloys containing these. These can be used alone or in combination of two or more thereof (for example, as a laminate of a plurality of layers, a mixed layer of a plurality of types, or the like).

In particular, when an alloy is used as the constituent material of the cathode 9, it is preferable to use an alloy containing a stable metal element such as Ag, Al, or Cu, specifically, an alloy such as MgAg, AlLi, or CuLi. By using such an alloy as the constituent material of the cathode 9, the electron injection efficiency and stability of the cathode 9 can be improved.
Although the average thickness of such a cathode 9 is not specifically limited, It is preferable that it is about 100-10000 nm, and it is more preferable that it is about 100-500 nm.
In addition, since the light emitting element 1 of this embodiment is a bottom emission type, the light transmittance of the cathode 9 is not particularly required. In the case of the top emission type, since it is necessary to transmit light from the cathode 9 side, the average thickness of the cathode 9 is preferably about 1 to 50 nm.

[Hole injection layer]
The hole injection layer 4 has a function of improving the hole injection efficiency from the anode 3 (that is, has a hole injection property).
Thus, by providing the hole injection layer 4 between the anode 3 and the hole transport layer 5 described later, the hole property from the anode 3 is improved, and as a result, the light emission efficiency of the light emitting element 1 is increased. Can do.

The hole injection layer 4 includes a material having a hole injection property (that is, a hole injection material).
The hole injecting material contained in the hole injecting layer 4 is not particularly limited. For example, copper phthalocyanine, 4,4 ′, 4 ″ -tris (N, N-phenyl-3-methylphenylamino) ) Triphenylamine (m-MTDATA), N, N′-bis- (4-diphenylamino-phenyl) -N, N′-diphenyl-biphenyl-4-4′-diamine, tetra-P-biphenylylbenzidine, etc. Is mentioned.

Among them, as the hole injecting material contained in the hole injecting layer 4, it is preferable to use an amine-based material from the viewpoint of excellent hole injecting property and hole transporting property, and a diaminobenzene derivative, a benzidine derivative (benzidine) It is more preferable to use a triamine-based compound or a tetraamine-based compound having both a “diaminobenzene” unit and a “benzidine” unit in the molecule.
The average thickness of the hole injection layer 4 is not particularly limited, but is preferably about 5 to 90 nm, and more preferably about 10 to 70 nm.
The hole injection layer 4 may be omitted depending on the constituent materials of the anode 3 and the hole transport layer 5.

(Hole transport layer)
The hole transport layer 5 has a function of transporting holes injected from the anode 3 through the hole injection layer 4 to the light emitting layer 6 (that is, has a hole transport property).
The hole transport layer 5 includes a material having a hole transport property (that is, a hole transport material).

  As the hole transporting material contained in the hole transporting layer 5, various p-type polymer materials and various p-type low molecular materials can be used alone or in combination. For example, N, N′— Di (1-naphthyl) -N, N′-diphenyl-1,1′-diphenyl-4,4′-diamine (NPD), N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1'-diphenyl-4,4'-diamine (TPD), tetraarylbenzidine derivatives such as tetra-P-biphenylylbenzidine, tetraaryldiaminofluorene compounds or derivatives thereof (amine compounds), etc. One or more of these can be used in combination.

Among them, the hole transport material contained in the hole transport layer 5 is preferably an amine-based material from the viewpoint of excellent hole injection property and hole transport property, and a benzidine derivative (a material having a benzidine skeleton). Is more preferable.
The average thickness of the hole transport layer 5 is not particularly limited, but is preferably about 5 to 90 nm, and more preferably about 10 to 70 nm.

(Light emitting layer)
The light emitting layer 6 emits light when energized between the anode 3 and the cathode 9 described above.
Such a light emitting layer 6 includes a light emitting material.
In particular, the light emitting layer 6 includes a compound represented by the following formula (1) (hereinafter, also simply referred to as “platinum complex compound”) as a light emitting material.

The light emitting layer 6 containing such a platinum complex compound (specifically, Pt (II) Tetrahenyl tetrabenzo porphrin: Pt (TPTBP)) can obtain light emission in a wavelength region (near infrared region) of 700 nm or more. .
In addition, the light emitting layer 6 may contain light emitting materials (various fluorescent materials, various phosphorescent materials) other than the above-described light emitting materials.

  As the constituent material of the light emitting layer 6, in addition to the light emitting material as described above, a host material to which this light emitting material is added (supported) as a guest material (dopant) is used. This host material recombines holes and electrons to generate excitons and to transfer the exciton energy to the luminescent material (Felster movement or Dexter movement) to excite the luminescent material. Have. Therefore, the light emission efficiency of the light emitting element 1 can be increased. Such a host material can be used by, for example, doping a host material with a light-emitting material that is a guest material as a dopant.

Such a host material is not particularly limited as long as it exhibits the functions described above with respect to the light emitting material to be used. Examples thereof include a distyrylarylene derivative and a compound represented by the following formula (7). Naphthacene derivatives, anthracene derivatives such as 2-t-butyl-9,10-di (2-naphthyl) anthracene (TBADN), perylene derivatives, distyrylbenzene derivatives, distyrylamine derivatives, bis (2-methyl-8-quinolinolato) ) (P-phenylphenolato) aluminum (BAlq), quinolinolato metal complexes such as tris (8-quinolinolato) aluminum complex (Alq ₃ ), triarylamine derivatives such as triphenylamine tetramers, oxadiazole derivatives , Rubrene and its derivatives, silole derivatives, dicarbazo Derivatives, oligothiophene derivatives, benzopyran derivatives, triazole derivatives, benzoxazole derivatives, benzothiazole derivatives, quinoline derivatives, 4,4′-bis (2,2′-diphenylvinyl) biphenyl (DPVBi), 3-phenyl-4- And carbazole derivatives such as (1′-naphthyl) -5-phenylcarbazole and 4,4′-N, N′-dicarbazolebiphenyl (CBP), and the like. One of these may be used alone, or two or more may be used. It can also be used in combination.
Among these, it is preferable to use an acene-based material as the host material. When the host material of the light-emitting layer 6 includes an acene-based material, electrons are efficiently transferred from the anthracene skeleton portion of the electron-transporting material in the electron-transport layer 7 to the acene-based material in the light-emitting layer 6. be able to.

  The acene-based material has little unintentional interaction with the light emitting material as described above. In addition, when an acene-based material (particularly an anthracene-based material or a tetracene-based material) is used as the host material, energy transfer from the host material to the light-emitting material can be efficiently performed. This is because (a) it is possible to generate a singlet excited state of the luminescent material by energy transfer from the triplet excited state of the acene-based material, and (b) a π electron cloud of the acene-based material and an electron cloud of the luminescent material. And (c) the overlap between the fluorescence spectrum of the acene-based material and the absorption spectrum of the light-emitting material is increased.

Therefore, when an acene-based material is used as the host material, the light emission efficiency of the light-emitting element 1 can be increased.
Acene-based materials are excellent in resistance to electrons and holes. Acene-based materials are also excellent in thermal stability. Therefore, the life of the light emitting element 1 can be extended. In addition, since the acene-based material is excellent in thermal stability, the host material can be prevented from being decomposed by heat at the time of film formation when the light emitting layer is formed using the vapor phase film formation method. Therefore, a light emitting layer having excellent film quality can be formed. As a result, the light emission efficiency of the light emitting element 1 can be increased and the life can be extended.

Furthermore, since the acene-based material itself does not easily emit light, the host material can be prevented from adversely affecting the emission spectrum of the light-emitting element 1.
Such an acene-based material is not particularly limited as long as it has an acene skeleton and exhibits the effects described above. For example, naphthalene derivatives, anthracene derivatives, naphthacene derivatives (tetracene derivatives), pentacene Derivatives, hexacene derivatives, heptacene derivatives and the like can be mentioned, and one or more of these can be used in combination, but anthracene derivatives (anthracene-based materials) or tetracene derivatives (tetracene-based materials) are preferably used. .

Thereby, electrons can be efficiently delivered from the anthracene skeleton portion of the electron transport material in the electron transport layer 7 to the anthracene material or tetracene material in the light emitting layer 6.
The tetracene-based material is not particularly limited as long as it has at least one tetracene skeleton in one molecule and can function as a host material as described above. For example, the following formula IRH The compound represented by -1 is preferably used, the compound represented by the following formula IRH-2 is more preferably used, and the compound represented by the following IRH-3 is more preferably used.

[In the formula IRH-1, n represents a natural number of 1 to 12, R represents a substituent or a functional group, and each independently represents a hydrogen atom, an alkyl group, or an aryl optionally having a substituent. Group represents an arylamino group. Moreover, R < ₁ > -R < ₄ > shows the aryl group and arylamino group which may have a hydrogen atom, an alkyl group, and a substituent each independently in said Formula IRH-2 and IRH-3. R _{1 to} R ₄ may be the same as or different from each other. ]

The tetracene-based material is preferably composed of carbon atoms and hydrogen atoms. Thereby, it is possible to prevent unintended interaction between the host material and the light emitting material. Therefore, the light emission efficiency of the light emitting element 1 can be increased. In addition, the resistance of the host material to potential and holes can be increased. Therefore, the lifetime of the light emitting element 1 can be extended.
Specifically, as the tetracene-based material, for example, compounds represented by the following formulas H1-1 to H1-11 and compounds represented by the following formulas H1-12 to H1-27 are preferably used.

  The anthracene-based material is not particularly limited as long as it has at least one anthracene skeleton in one molecule and can exhibit the function as the host material as described above. It is preferable to use a compound represented by the formula IRH-4 or a derivative thereof, and it is more preferable to use a compound represented by the following formulas IRH5 to IRH-8.

［前記式ＩＲＨ−４中、ｎは、１〜１０の自然数を示し、Ｒは、それぞれ独立に、水素原子、アルキル基、置換基を有していてもよいアリール基、アリールアミノ基を示す。また、前記式ＩＲＨ−５〜ＩＲＨ−８中、Ｒ_１、Ｒ_２は、それぞれ独立に、水素原子、アルキル基、置換基を有していてもよいアリール基、アリールアミノ基を示す。また、Ｒ_１、Ｒ_２は、互いに同じであっても異なっていてもよい。］

[In Formula IRH-4, n represents a natural number of 1 to 10, and R independently represents a hydrogen atom, an alkyl group, an aryl group which may have a substituent, or an arylamino group. Moreover, R < ₁ >, R < ₂ > shows the aryl group and arylamino group which may have a hydrogen atom, an alkyl group, and a substituent each independently in said Formula IRH-5-IRH-8. R ₁ and R ₂ may be the same as or different from each other. ]

The anthracene-based material is preferably composed of carbon atoms and hydrogen atoms. Thereby, it is possible to prevent unintended interaction between the host material and the light emitting material. Therefore, the light emission efficiency of the light emitting element 1 can be increased. In addition, the resistance of the host material to potential and holes can be increased. Therefore, the lifetime of the light emitting element 1 can be extended.
Specifically, examples of the anthracene-based material include compounds represented by the following formulas H2-1 to H2-16, compounds represented by the following formulas H2-21 to H2-40, and formulas H2-51 to H2-70. It is preferable to use a compound represented by:

The content (doping amount) of the light emitting material in the light emitting layer 6 including such a light emitting material and the host material is preferably 0.01 to 10 wt%, and more preferably 0.1 to 5 wt%. . Luminous efficiency can be optimized by setting the content of the light emitting material within such a range.
Moreover, although the average thickness of the light emitting layer 6 is not specifically limited, It is preferable that it is about 1-60 nm, and it is more preferable that it is about 3-50 nm.

(Electron transport layer)
The electron transport layer 7 has a function of transporting electrons injected from the cathode 9 through the electron injection layer 8 to the light emitting layer 6.
The electron transport layer 7 includes an electron transport material. In particular, the electron transport layer 7 includes a compound having an azaindolizine skeleton and an anthracene skeleton in the molecule (hereinafter, also simply referred to as “azaindolizine compound”) as an electron transporting material.
In this way, since a compound having an azaindolizine skeleton and an anthracene skeleton in the molecule is used as the electron transport material of the electron transport layer 7 adjacent to the light emitting layer 6, electrons are transferred from the electron transport layer 7 to the light emitting layer 6. It can be transported efficiently. Therefore, the light emission efficiency of the light emitting element 1 can be improved.

In addition, since the electron transport from the electron transport layer 7 to the light emitting layer 6 can be efficiently performed, the driving voltage of the light emitting element 1 can be lowered, and accordingly, the life of the light emitting element 1 is extended. be able to.
Furthermore, since a compound having an azaindolizine skeleton and an anthracene skeleton in a molecule is excellent in stability (resistance) against electrons and holes, the life of the light-emitting element 1 can also be extended in this respect.

The electron transporting material (azaindolizine compound) used for the electron transporting layer 7 preferably has one or two azaindolizine skeletons and anthracene skeletons contained in one molecule. Thereby, the electron transport property and the electron injection property of the electron transport layer 7 can be made excellent.
Specifically, examples of the azaindolizine compound used for the electron transport layer 7 include compounds represented by the following formulas ELT-A1 to ELT-A24, and formulas ELT-B1 to ELT-B12. It is preferable to use such a compound and the compounds represented by the following ELT-C1 to ELT-C20.

Such an azaindolizine compound is excellent in electron transport property and electron injection property. Therefore, the light emission efficiency of the light emitting element 1 can be improved.
The reason why the electron transport property and electron injection property of the azaindolizine compound is excellent is considered as follows.
In the azaindolizine-based compound having an azaindolizine skeleton and an anthracene skeleton in the molecule as described above, the entire molecule is connected by a π-conjugated system, and therefore the electron cloud spreads over the entire molecule.

  The azaindolizine skeleton portion of the azaindolizine compound has a function of accepting electrons and a function of sending the received electrons to the anthracene skeleton portion. On the other hand, the portion of the anthracene skeleton of the azaindolizine compound has a function of accepting electrons from the portion of the azaindolizine skeleton and a layer adjacent to the anode 3 side of the electron transport layer 7, that is, a light emitting layer. 6 is provided.

  Specifically, the azaindolizine skeleton portion of the azaindolizine compound has two nitrogen atoms, and one of the nitrogen atoms (on the side close to the anthracene skeleton portion) has an sp2 hybrid orbital. The nitrogen atom on the other side (the side far from the anthracene skeleton portion) has an sp3 hybrid orbital. Nitrogen atom having sp2 hybrid orbital constitutes part of the conjugated system of azaindolizine compound molecule, and has higher electronegativity than carbon atom, and has higher strength to attract electrons. Function as. On the other hand, a nitrogen atom having an sp3 hybrid orbital is not a normal conjugated system, but has an unshared electron pair, so that the electron functions as a part that sends electrons toward the conjugated system of the molecule of the azaindolizine compound. .

  On the other hand, since the anthracene skeleton portion of the azaindolizine compound is electrically neutral, electrons can be easily accepted from the azaindolizine skeleton portion. In addition, since the anthracene skeleton portion of the azaindolizine compound has a large orbital overlap with the constituent material of the light emitting layer 6, particularly the host material (acene material), electrons are easily received by the host material of the light emitting layer 6. Can pass.

In addition, since the azaindolizine-based compound is excellent in the electron transporting property and the electron injecting property as described above, the driving voltage of the light emitting element 1 can be lowered as a result.
The azaindolizine skeleton portion is stable even when a nitrogen atom having an sp2 hybrid orbital is reduced, and is stable even if a nitrogen atom having an sp3 hybrid orbital is oxidized. Therefore, such an azaindolizine compound has high stability against electrons and holes. As a result, the lifetime of the light emitting element 1 can be extended.

In addition, when the electron transport layer 7 is used in combination of two or more of the electron transport materials as described above, the electron transport layer 7 may be composed of a mixed material in which two or more electron transport materials are mixed, or different. You may be comprised by laminating | stacking the some layer comprised with the electron transport material.
Although the average thickness of the electron carrying layer 7 is not specifically limited, It is preferable that it is about 0.5-100 nm, and it is more preferable that it is about 1-50 nm.

(Electron injection layer)
The electron injection layer 8 has a function of improving the electron injection efficiency from the cathode 9.
Examples of the constituent material (electron injectable material) of the electron injection layer 8 include various inorganic insulating materials and various inorganic semiconductor materials.
Examples of such inorganic insulating materials include alkali metal chalcogenides (oxides, sulfides, selenides, tellurides), alkaline earth metal chalcogenides, alkali metal halides, and alkaline earth metal halides. Of these, one or two or more of these can be used in combination. By forming the electron injection layer 8 using these as main materials, the electron injection property can be further improved. In particular, alkali metal compounds (alkali metal chalcogenides, alkali metal halides, and the like) have a very low work function, and the light-emitting element 1 can be obtained with high luminance by forming the electron injection layer 8 using the work function. Become.

Examples of the alkali metal chalcogenide include Li ₂ O, LiO, Na ₂ S, Na ₂ Se, and NaO.
Examples of the alkaline earth metal chalcogenide include CaO, BaO, SrO, BeO, BaS, MgO, and CaSe.
Examples of the alkali metal halide include CsF, LiF, NaF, KF, LiCl, KCl, and NaCl.
Examples of the alkaline earth metal halide include CaF ₂ , BaF ₂ , SrF ₂ , MgF ₂ , and BeF ₂ .

In addition, as the inorganic semiconductor material, for example, an oxide including at least one element of Li, Na, Ba, Ca, Sr, Yb, Al, Ga, In, Cd, Mg, Si, Ta, Sb, and Zn , Nitrides, oxynitrides, and the like, and one or more of these can be used in combination.
The average thickness of the electron injection layer 8 is not particularly limited, but is preferably about 0.1 to 1000 nm, more preferably about 0.2 to 100 nm, and about 0.2 to 50 nm. Further preferred.
The electron injection layer 8 may be omitted depending on the constituent materials and thicknesses of the cathode 9 and the electron transport layer 7.

(Sealing member)
The sealing member 10 is provided so as to cover the anode 3, the laminate 14, and the cathode 9, and has a function of hermetically sealing them and blocking oxygen and moisture. By providing the sealing member 10, effects such as improvement of the reliability of the light emitting element 1 and prevention of deterioration / deterioration (improvement of durability) can be obtained.
Examples of the constituent material of the sealing member 10 include Al, Au, Cr, Nb, Ta, Ti, alloys containing these, silicon oxide, various resin materials, and the like. In addition, when using the material which has electroconductivity as a constituent material of the sealing member 10, in order to prevent a short circuit, between the sealing member 10 and the anode 3, the laminated body 14, and the cathode 9 is required. Accordingly, an insulating film is preferably provided.

Further, the sealing member 10 may be formed in a flat plate shape so as to face the substrate 2 and be sealed with a sealing material such as a thermosetting resin.
According to the light emitting device 1 configured as described above, a platinum complex compound is used as the light emitting material of the light emitting layer 6, and an azaindolizine compound is used as the electron transporting material of the electron transport layer 7. In addition to enabling light emission in the infrared region, high efficiency and long life can be achieved.
The above light emitting element 1 can be manufactured as follows, for example.

[1] First, the substrate 2 is prepared, and the anode 3 is formed on the substrate 2.
The anode 3 is, for example, a chemical vapor deposition method (CVD) such as plasma CVD or thermal CVD, a dry plating method such as vacuum deposition, a wet plating method such as electrolytic plating, a thermal spraying method, a sol-gel method, a MOD method, or a metal foil. It can be formed by using, for example, bonding.
[2] Next, the hole injection layer 4 is formed on the anode 3.
The hole injection layer 4 is preferably formed by, for example, a vapor phase process using a CVD method, a dry plating method such as vacuum deposition or sputtering, or the like.

For example, the hole injection layer 4 may be dried (desolvent or solvent-free) after supplying a material for forming a hole injection layer obtained by dissolving a hole injection material in a solvent or dispersing in a dispersion medium onto the anode 3. It can also be formed by dedispersing medium).
As a method for supplying the hole injection layer forming material, for example, various coating methods such as a spin coating method, a roll coating method, and an ink jet printing method can be used. By using such a coating method, the hole injection layer 4 can be formed relatively easily.

Examples of the solvent or dispersion medium used for the preparation of the hole injection layer forming material include various inorganic solvents, various organic solvents, or mixed solvents containing these.
The drying can be performed, for example, by standing in an atmospheric pressure or a reduced pressure atmosphere, heat treatment, or blowing an inert gas.
Prior to this step, the upper surface of the anode 3 may be subjected to oxygen plasma treatment. Thereby, it is possible to impart lyophilicity to the upper surface of the anode 3, remove (clean) organic substances adhering to the upper surface of the anode 3, adjust the work function near the upper surface of the anode 3, and the like. .
Here, the oxygen plasma treatment conditions include, for example, a plasma power of about 100 to 800 W, an oxygen gas flow rate of about 50 to 100 mL / min, a conveyance speed of the member to be treated (anode 3) of about 0.5 to 10 mm / sec, and a substrate. The temperature of 2 is preferably about 70 to 90 ° C.

[3] Next, the hole transport layer 5 is formed on the hole injection layer 4.
The hole transport layer 5 is preferably formed by a vapor phase process using, for example, a CVD method, a dry plating method such as vacuum evaporation or sputtering.
In addition, a hole transport layer forming material obtained by dissolving a hole transport material in a solvent or dispersing in a dispersion medium is supplied onto the hole injection layer 4 and then dried (desolvent or dedispersion medium). Can also be formed.

[4] Next, the light emitting layer 6 is formed on the hole transport layer 5.
The light emitting layer 6 can be formed, for example, by a vapor phase process using a dry plating method such as vacuum deposition.
[5] Next, the electron transport layer 7 is formed on the light emitting layer 6.
The electron transport layer 7 is preferably formed, for example, by a vapor phase process using a dry plating method such as vacuum deposition.
For example, the electron transport layer 7 is dried (desolvent or dedispersed) after supplying an electron transport layer forming material obtained by dissolving an electron transport material in a solvent or dispersing in a dispersion medium onto the light emitting layer 6. It can also be formed by the medium.

[6] Next, the electron injection layer 8 is formed on the electron transport layer 7.
In the case where an inorganic material is used as the constituent material of the electron injection layer 8, the electron injection layer 8 is formed by, for example, a vapor phase process using a CVD method, a dry plating method such as vacuum deposition or sputtering, or the application and baking of inorganic fine particle ink. Etc. can be used.
[7] Next, the cathode 9 is formed on the electron injection layer 8.
The cathode 9 can be formed by using, for example, a vacuum deposition method, a sputtering method, bonding of metal foil, application and firing of metal fine particle ink, or the like.
The light emitting element 1 is obtained through the steps as described above.
Finally, the sealing member 10 is covered so as to cover the obtained light emitting element 1 and bonded to the substrate 2.

(Light emitting device)
Next, an embodiment of the light emitting device of the present invention will be described.
FIG. 2 is a longitudinal sectional view showing an embodiment of a display device to which the light emitting device of the present invention is applied.
A display device 100 shown in FIG. 2 includes a substrate 21, a plurality of light emitting elements 1A, and a plurality of driving transistors 24 for driving the respective light emitting elements 1A. Here, the display device 100 is a display panel having a top emission structure.

A plurality of driving transistors 24 are provided on the substrate 21, and a planarizing layer 22 made of an insulating material is formed so as to cover these driving transistors 24.
Each driving transistor 24 includes a semiconductor layer 241 made of silicon, a gate insulating layer 242 formed on the semiconductor layer 241, a gate electrode 243 formed on the gate insulating layer 242, a source electrode 244, and a drain electrode. H.245.

On the planarization layer, the light emitting element 1A is provided corresponding to each driving transistor 24.
In the light emitting element 1 </ b> A, a reflective film 32, a corrosion preventing film 33, an anode 3, a stacked body (organic EL light emitting unit) 14, a cathode 13, and a cathode cover 34 are stacked in this order on a planarizing layer 22. In the present embodiment, the anode 3 of each light emitting element 1 </ b> A constitutes a pixel electrode and is electrically connected to the drain electrode 245 of each driving transistor 24 by a conductive portion (wiring) 27. Moreover, the cathode 13 of each light emitting element 1A is a common electrode.

2A emits light in the near infrared region.
A partition wall 31 is provided between the adjacent light emitting elements 1A. Further, an epoxy layer 35 made of an epoxy resin is formed on these light emitting elements 1A so as to cover them.
A sealing substrate 20 is provided on the epoxy layer 35 so as to cover them.
The display device 100 as described above can be used as a near infrared display for military use, for example.
According to such a display device 100, light emission in the near infrared region is possible. In addition, since the light-emitting element 1A having high efficiency and long life is provided, the reliability is excellent.

(Authentication device)
Next, an embodiment of the authentication device of the present invention will be described.
FIG. 3 is a diagram showing an embodiment of the authentication device of the present invention.
An authentication apparatus 1000 shown in FIG. 3 is a biometric authentication apparatus that authenticates an individual using biometric information of the biometric F (fingertip in this embodiment).

The authentication apparatus 1000 includes a light source 100B, a cover glass 1001, a microlens array 1002, a light receiving element group 1003, a light emitting element driving unit 1006, a light receiving element driving unit 1004, and a control unit 1005.
The light source 100 </ b> B includes a plurality of the light emitting elements 1 described above, and irradiates near-infrared light toward the living body F that is an imaging target. For example, the plurality of light emitting elements 1 of the light source 100 </ b> B are arranged along the outer periphery of the cover glass 1001.
The cover glass 1001 is a part where the living body F is in contact with or close to.
The microlens array 1002 is provided on the side opposite to the side of the cover glass 1001 where the living body F is in contact with or close to. The microlens array 1002 includes a plurality of microlenses arranged in a matrix.

  The light receiving element group 1003 is provided on the side opposite to the cover glass 1001 with respect to the microlens array 1002. The light receiving element group 1003 includes a plurality of light receiving elements provided in a matrix corresponding to the plurality of microlenses of the microlens array 1002. As each light receiving element of the light receiving element group 1003, for example, a CCD (Charge Coupled Device), a CMOS, or the like can be used.

The light emitting element driving unit 1006 is a driving circuit that drives the light source 100B.
The light receiving element driving unit 1004 is a drive circuit that drives the light receiving element group 1003.
The control unit 1005 is, for example, an MPU, and has a function of controlling driving of the light emitting element driving unit 1006 and the light receiving element driving unit 1004.
In addition, the control unit 1005 has a function of performing authentication of the living body F by comparing the light reception result of the light receiving element group 1003 with biometric authentication information stored in advance.

For example, the control unit 1005 generates an image pattern (for example, a vein pattern) related to the living body F based on the light reception result of the light receiving element group 1003. Then, the control unit 1005 compares the image pattern with an image pattern stored in advance as biometric authentication information, and performs authentication (for example, vein authentication) of the biometric F based on the comparison result.
According to such an authentication apparatus 1000, biometric authentication can be performed using near infrared light. Further, since the light-emitting element 1 having high efficiency and long life is provided, the reliability is excellent.
Such an authentication apparatus 1000 can be incorporated into various electronic devices.

(Electronics)
FIG. 4 is a perspective view showing a configuration of a mobile (or notebook) personal computer to which the electronic apparatus of the present invention is applied.
In this figure, a personal computer 1100 includes a main body 1104 provided with a keyboard 1102 and a display unit 1106 provided with a display. The display unit 1106 is rotatable with respect to the main body 1104 via a hinge structure. It is supported by.
In the personal computer 1100, the main body 1104 is provided with the authentication device 1000 described above.

According to such a personal computer 1100, since the light-emitting element 1 with high efficiency and long life is provided, the reliability is excellent.
In addition to the personal computer (mobile personal computer) shown in FIG. 4, the electronic apparatus of the present invention may be, for example, a mobile phone, a digital still camera, a television, a video camera, a viewfinder type, or a monitor direct view type video tape. Recorder, laptop personal computer, car navigation system, pager, electronic organizer (including communication function), electronic dictionary, calculator, electronic game device, word processor, workstation, video phone, security TV monitor, electronic binoculars, POS Terminals, devices equipped with a touch panel (for example, cash dispensers of financial institutions, automatic ticket vending machines), medical devices (for example, electronic thermometers, blood pressure monitors, blood glucose meters, pulse measuring devices, pulse measuring devices, electrocardiographic display devices, ultrasonic diagnostics) Device, endoscope display device), fish finder Various measuring instruments, gauges (e.g., gages for vehicles, aircraft, and ships), a flight simulator, various monitors, and a projection display such as a projector.
As described above, the light-emitting element, the light-emitting device, the authentication device, and the electronic device of the present invention have been described based on the illustrated embodiments, but the present invention is not limited to these.
For example, the light emitting element and the light emitting device of the present invention may be used as a light source for illumination.

Next, specific examples of the present invention will be described.
1. Production of Host Material (Anthracene Material) (Synthesis Example C1) Synthesis of Compound Represented by Formula H2-34

Synthesis (C1-1)
Commercially available 2-naphthaleneboronic acid (2.1 g) and 9,10-dibromoanthracene (5 g) were dissolved in 50 ml of dimethoxyethane and heated to 80 ° C. Thereto, 50 ml of distilled water and 10 g of sodium carbonate were added. Further, 0.4 g of tetrakistriphenylphosphine palladium (0) was added thereto.
After 3 hours, toluene was extracted with a separatory funnel and purified with silica gel (SiO ₂ 500 g).
As a result, 3 g of pale yellowish white crystals (9-bromo-10-naphthalen-2-yl-anthracene) were obtained.

Synthesis (C1-2)
Under Ar, 10.5 g of commercially available 2-naphthaleneboronic acid and 17.5 g of 1,4-dibrobenzene were dissolved in 250 ml of dimethoxyethane and heated to 80 ° C. in a 500 ml flask. Thereto, 250 ml of distilled water and 30 g of sodium carbonate were added. Further, 2 g of tetrakistriphenylphosphine palladium (0) was added thereto.
After 3 hours, toluene was extracted with a separatory funnel and purified with silica gel (SiO ₂ 500 g).
This obtained 10 g of white crystals (2- (4-bromophenyl) -naphthalene).

Synthesis (C1-3)
Under Ar, in a 1 liter flask, 10 g of 2- (4-bromophenyl) -naphthalene obtained in synthesis (C1-2) and 500 ml of dehydrated tetrahydrofuran were added, and a 1.6 M n-BuLi / hexane solution at −60 ° C. 22 ml was added dropwise over 30 minutes. After 30 minutes, 7 g of triisopropyl borate was added. After dropping, the reaction was allowed to proceed overnight at the expected temperature. After the reaction, 100 ml of water was added dropwise, and then extracted with 2 liters of toluene and separated. The organic layer was concentrated, recrystallized, filtered and dried to obtain 5 g of a white phenylboronic acid derivative.

Synthesis (C1-4)
Under Ar, a 500 ml flask was charged with 3 g of 9-bromo-10-naphthalen-2-yl-anthracene obtained by synthesis (C1-1) and 3 g of boronic acid obtained by synthesis (C1-3). Dissolved in dimethoxyethane and heated to 80 ° C. Thereto, 250 ml of distilled water and 10 g of sodium carbonate were added. Further, 0.5 g of tetrakistriphenylphosphine palladium (0) was added thereto.
After 3 hours, toluene was extracted with a separatory funnel and purified by silica gel chromatography.
As a result, 3 g of a pale yellowish white solid (compound represented by the formula H2-34) was obtained.

  (Synthesis Example C2) Synthesis of compound represented by formula H2-61

Synthesis (C2-1)
Under Ar, 5 g of Biantron and 150 ml of dry diethyl ether were placed in a 300 ml flask. 5.5 ml of a commercially available phenyl lithium reagent (19% butyl ether solution) was added thereto and stirred at room temperature for 3 hours. Thereafter, 10 ml of water was added, and the mixture was transferred to a separatory funnel, and the target product was extracted with toluene, dried, and separated and purified on silica gel (SiO ₂ 500 g).
As a result, 5 g of a white target product (10, 10′-diphenyl-10H, 10′H- [9,9 ′] bianthracenylidene-10, 10′-diol) was obtained.

Synthesis (C2-2)
5 g of the diol obtained in synthesis (C2-1) and 300 ml of acetic acid were placed in a 500 ml flask. A solution prepared by dissolving 5 g of tin (II) chloride (anhydrous) in 5 g of hydrochloric acid (35%) was added and stirred for 30 minutes. Then, it moved to the separating funnel, added toluene, liquid-separated and washed with distilled water, and dried. The obtained solid was purified by silica gel (SiO ₂ 500 g) to obtain 5.5 g of a yellow white solid (compound represented by the formula H2-61).

  (Synthesis Example C3) Compound represented by Formula H2-66

Synthesis (C3-1)
Commercially available phenylboronic acid (2.2 g) and 9,10-dibromoanthracene (6 g) were dissolved in 100 ml of dimethoxyethane and heated to 80 ° C. Thereto, 50 ml of distilled water and 10 g of sodium carbonate were added. Further, 0.5 g of tetrakistriphenylphosphine palladium (0) was added thereto.
After 3 hours, toluene was extracted with a separatory funnel and purified with silica gel (SiO ₂ 500 g).
As a result, 4 g of yellowish white crystals (9-bromo-10-phenyl-anthracene) were obtained.

Synthesis (C3-2)
Under Ar, in a 500 ml flask, 4 g of 9-bromo-10-phenyl-anthracene obtained by synthesis (C3-1) and 0.8 g of commercially available phenylenediboronic acid were dissolved in 200 ml of dimethoxyethane, and 80 ° C. Heated. Thereto, 250 ml of distilled water and 10 g of sodium carbonate were added. Further, 0.5 g of tetrakistriphenylphosphine palladium (0) was added thereto.
After 3 hours, toluene was extracted with a separatory funnel and purified using silica gel chromatography.
As a result, 2 g of a pale yellowish white solid (compound represented by the formula H2-66) was obtained.

2. Production of Electron Transport Material (Azaindolizine Compound) (Synthesis Example D1) Synthesis of Compound Represented by Formula ETL-A3

Synthesis (D1-1)
Commercially available 2-naphthaleneboronic acid (2.1 g) and 9,10-dibromoanthracene (5 g) were dissolved in 50 ml of dimethoxyethane and heated to 80 ° C. Thereto, 50 ml of distilled water and 10 g of sodium carbonate were added. Further, 0.4 g of tetrakistriphenylphosphine palladium (0) was added thereto.
After 3 hours, toluene was extracted with a separatory funnel and purified with silica gel (SiO ₂ 500 g).
As a result, 3 g of pale yellowish white crystals (9-bromo-10-naphthalen-2-yl-anthracene) were obtained.

Synthesis (D1-2)
Under Ar, in a 1-liter flask, 3 g of 9-bromo-10-naphthalen-2-yl-anthracene obtained in Synthesis (D1-1) and 500 ml of dehydrated tetrahydrofuran were placed, and 1.6M n-BuLi was added at -60 ° C. / 6 ml of hexane solution was added dropwise over 10 minutes. After 30 minutes, 1.5 g of triisopropyl borate was added. After dropping, the reaction was allowed to proceed for 3 hours at the expected temperature. After the reaction, 50 mL of distilled water was added dropwise, and then extracted and separated with 1 liter of toluene. The organic layer was concentrated, recrystallized, filtered and dried to obtain 2 g of a white target product (boronic acid form).

Synthesis (D1-3)
Under Ar, 3.4 g of 2-aminopyridine was weighed into a 300 ml flask, and 40 ml of ethanol and 40 ml of acetone were added and dissolved therein. 4-bromophenacyl bromide 10g was added there, and it was made to heat and reflux. After 3 hours, heating was discontinued and cooled to room temperature. After removing the solvent under reduced pressure, it was dissolved by heating in 1 liter of methanol, and after removing insoluble impurities by filtration, the concentrated and precipitated product was collected.
As a result, 8 g of a target white solid (2- (4-bromophenyl) -imidazo [1,2-a] pyridine) was obtained.

Synthesis (D1-4)
Under Ar, in a 500 ml flask, 2 g of the boronic acid compound obtained by synthesis (D1-2) and 1.7 g of the imidazopyridine derivative obtained by synthesis (D1-3) were dissolved in 200 ml of dimethoxyethane. Heated to ° C. Thereto, 250 ml of distilled water and 10 g of sodium carbonate were added. Further, 0.5 g of tetrakistriphenylphosphine palladium (0) was added thereto.
After 3 hours, toluene was extracted with a separatory funnel and purified with silica gel (SiO ₂ 500 g).
As a result, 2 g of a white solid (compound represented by the formula ETL-A3) was obtained.

3. Production of light emitting device (Example 1)
<1> First, a transparent glass substrate having an average thickness of 0.5 mm was prepared. Next, an ITO electrode (anode) having an average thickness of 100 nm was formed on the substrate by sputtering.
And after immersing a board | substrate in order of acetone and 2-propanol and ultrasonically cleaning, oxygen plasma treatment and argon plasma treatment were performed. Each of these plasma treatments was performed at a plasma power of 100 W, a gas flow rate of 20 sccm, and a treatment time of 5 seconds with the substrate heated to 70 to 90 ° C.

<2> Next, an amine-based hole transporting material (tetrakis-p-biphenylyl-benzidine) was deposited on the ITO electrode by a vacuum deposition method to form a hole transporting layer having an average thickness of 50 nm.
<3> Next, the constituent material of the light emitting layer was vapor-deposited on the hole transport layer by a vacuum vapor deposition method to form a light emitting layer having an average thickness of 25 nm. As a constituent material of the light emitting layer, a compound (Pt (TPTBP)) represented by the above formula (1) was used as a light emitting material (guest material), and tris (8-quinolinolato) aluminum (Alq ₃ ) was used as a host material. . Further, the content (dope concentration) of the light emitting material (dopant) in the light emitting layer was 4.0 wt%.

<4> Next, a compound represented by the formula ETL-A3 (azaindolizine compound) was formed on the light emitting layer by a vacuum deposition method to form an electron transport layer having an average thickness of 80 nm.
<5> Next, on the electron transport layer, lithium fluoride (LiF) was formed by a vacuum deposition method to form an electron injection layer having an average thickness of 1 nm.
<6> Next, Al was formed into a film by the vacuum evaporation method on the electron injection layer. Thereby, a cathode having an average thickness of 100 nm made of Al was formed.
<7> Next, a glass protective cover (sealing member) was placed over the formed layers, and fixed and sealed with an epoxy resin.
The light emitting device was manufactured through the above steps.

(Example 2)
A light emitting device was produced in the same manner as in Example 1 except that the compound represented by the formula H2-34 (anthracene material) was used as the host material of the light emitting layer.
(Example 3)
A light emitting device was manufactured in the same manner as in Example 1 except that the compound represented by the formula H2-61 (anthracene material) was used as the host material of the light emitting layer.

Example 4
A light emitting device was manufactured in the same manner as in Example 1 except that the compound represented by the formula H2-66 (anthracene material) was used as the host material of the light emitting layer.
(Example 5)
A light emitting device was manufactured in the same manner as in Example 1 except that the average thickness of the light emitting layer was 45 nm and the average thickness of the electron transport layer was 60 nm.

(Example 6)
A light emitting device was manufactured in the same manner as in Example 1 except that the average thickness of the light emitting layer was 15 nm and the average thickness of the electron transport layer was 90 nm.
(Example 7)
A light emitting device was produced in the same manner as in Example 1 except that the electron transport layer was formed by stacking Alq ₃ and the compound represented by the formula ETL-A3 in this order by vacuum deposition.
Here, in the electron transport layer, the average thickness of the layer composed of Alq ₃ was 20 nm, and the average thickness of the layer composed of the compound represented by the formula ETL-A3 was 60 nm.

(Comparative Example 1)
A light emitting device was produced in the same manner as in Example 1 except that 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was used as the electron transporting material for the electron transport layer.
(Comparative Example 2)
The compound represented by the formula H2-34 (anthracene material) is used as the host material of the light emitting layer, and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (as the electron transporting material of the electron transport layer) A light emitting device was manufactured in the same manner as in Example 1 except that BCP) was used.

(Comparative Example 3)
The compound represented by the formula H2-61 (anthracene material) is used as the host material of the light emitting layer, and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (as the electron transporting material of the electron transport layer) A light emitting device was manufactured in the same manner as in Example 1 except that BCP) was used.

(Comparative Example 4)
The compound represented by the formula H2-66 (anthracene material) is used as the host material of the light emitting layer, and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline ( A light emitting device was manufactured in the same manner as in Example 1 except that BCP) was used.

(Comparative Example 5)
2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) is used as the electron transport material of the electron transport layer, the average thickness of the light emitting layer is 45 nm, and the average thickness of the electron transport layer is A light emitting device was manufactured in the same manner as in Example 1 except that the thickness was 60 nm.

(Comparative Example 6)
2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) is used as the electron transporting material of the electron transport layer, the average thickness of the light emitting layer is 15 nm, and the average thickness of the electron transport layer is A light emitting device was manufactured in the same manner as in Example 1 except that the thickness was 90 nm.

(Comparative Example 7)
A light emitting device was manufactured in the same manner as in Example 1 except that the electron transport layer was formed by laminating Alq ₃ and BCP in this order by vacuum deposition.
Here, in the electron transport layer, the average thickness of the layer composed of Alq ₃ was 20 nm, and the average thickness of the layer composed of BCP was 60 nm.
(Comparative Example 8)
A light emitting device was manufactured in the same manner as in Example 1 except that Alq ₃ was used as the electron transporting material of the electron transporting layer.

4). Evaluation About each Example and each comparative example, using a constant current power source (KEITLEY2400 manufactured by Toyo Corporation), a constant current of 100 mA / cm ² was passed through the light emitting element, and the emission peak wavelength and emission power at that time were spectrally radiated. It measured using the luminance meter (CS-2000 by Konica Minolta Sensing Co., Ltd.).

The voltage value (drive voltage) at that time was also measured.
Furthermore, the time (LT80) during which the luminance was 80% of the initial luminance was measured.
These measurement results are shown in Table 1. In addition, the emission spectrum of the light emitting element in Examples 1 and 2 and Comparative Examples 1 and 2 is shown in FIG. 5, and the lifetime in Examples 1-3 and Comparative Example 1 is shown in FIG.

As is clear from Table 1, the light emitting elements of the respective examples emit light in the near infrared region, and higher light emission power is obtained as compared with the light emitting elements of the comparative examples. Moreover, the light emitting element of each Example can suppress a drive voltage compared with the light emitting element of each comparative example. For these reasons, the light emitting elements of the respective examples have excellent luminous efficiency.
Moreover, the light emitting element of each Example has a long lifetime compared with the light emitting element of each comparative example.

  DESCRIPTION OF SYMBOLS 1, 1A ... Light emitting element 2 ... Substrate 3 ... Anode 4 ... Hole injection layer 5 ... Hole transport layer 6 ... Light emitting layer 7 ... Electron transport layer 8 ... Electron injection layer 9 ... Cathode DESCRIPTION OF SYMBOLS 10 ... Sealing member 13 ... Cathode 14 ... Laminated body 100 ... Display apparatus 20 ... Sealing substrate 21 ... Substrate 22 ... Planarization layer 24 ... Driving transistor 241 ... Semiconductor layer 242 ... Gate insulating layer 243 …… Gate electrode 244 …… Source electrode 245 …… Drain electrode 27 …… Wiring 31 …… Partition wall 32 …… Reflection film 33 …… Corrosion prevention film 34 …… Cathode cover 35 …… Epoxy layer 100B …… Light source 1000 …… Authentication device 1001 …… Cover glass 1002 …… Microlens array 1003 …… Light receiving element group 1004 …… Light receiving element driving unit 1005 …… Control unit 10 06 …… Light emitting element driving unit 1100 …… Personal computer 1102 …… Keyboard 1104 …… Main body 1106 …… Display unit F …… Biological body

Claims (11)

The anode,
A cathode,
A light emitting layer that is provided between the anode and the cathode, and emits light when energized between the anode and the cathode;
An electron transport layer provided between and in contact with the light emitting layer between the cathode and the light emitting layer, and having an electron transporting property;
The light emitting layer includes a compound represented by the following formula (1) as a light emitting material,
The light-emitting element, wherein the electron transport layer includes a compound having an azaindolizine skeleton and an anthracene skeleton in the molecule as an electron transport material.

  2. The light-emitting element according to claim 1, wherein the electron transporting material has one or two azaindolizine skeletons and anthracene skeletons in one molecule.   The light-emitting element according to claim 1, wherein the light-emitting layer includes a host material that holds the light-emitting material.   The light-emitting element according to claim 3, wherein the host material includes an acene-based material.   The light emitting device according to claim 4, wherein the acene material is an anthracene material.   The light-emitting element according to claim 4, wherein the acene-based material is a tetracene-based material.   The light-emitting element according to claim 4, wherein the acene-based material is composed of carbon atoms and hydrogen atoms.   The light-emitting element according to claim 3, wherein the host material includes a quinolinolato metal complex.   A light-emitting device comprising the light-emitting element according to claim 1.   An authentication apparatus comprising the light emitting device according to claim 1.   An electronic apparatus comprising the light emitting element according to claim 1.

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