JP6809241B2 - Compounds, compounds for light emitting elements, light emitting elements, light emitting devices, light sources, authentication devices and electronic devices - Google Patents

Description

The present invention relates to a benzo-bis-thiazazole compound, a compound for a light emitting element, a light emitting element, a light emitting device, a light source, a certification device, and an electronic device.

An organic electroluminescence device (so-called organic EL device) is a light emitting device having a structure in which at least one luminescent organic layer is interposed between an anode and a cathode. In such a light emitting element, 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 in the light emitting layer. Excitons are generated by recombination, and when these excitons return to the ground state, the energy component is emitted as light.

As such a light emitting element, one that emits light in a long wavelength region exceeding 700 nm is known (see, for example, Patent Documents 1 and 2).

For example, in the light emitting elements described in Patent Documents 1 and 2, a material in which an amine as an electron donor and a nitrile group as an electron acceptor coexist in the molecule as a functional group is used as a dopant of a light emitting layer to emit light. The wavelength is lengthened.

It has also been reported that a benzo-bis-thiadiazole-based compound is used as the light emitting material of the light emitting layer (see, for example, Non-Patent Document 1).

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 a wide wavelength region.

In addition, a highly efficient and long-life light emitting element that emits surface light in the near infrared region includes, for example, a light source for biometric authentication that authenticates an individual using biometric information such as veins and fingerprints, various light emitting devices, and a biosensor. It is desired to realize the light source of the above and as a light source of electronic devices.

JP 2000-091073 Japanese Unexamined Patent Publication No. 2001-11570

Adv. Mater. 2009, 21, 111-116

An object of the present invention is a compound capable of obtaining a highly efficient and long-life light emitting element that emits light in a near infrared region in a wide wavelength region by being included in a light emitting layer included in the light emitting element, a compound for a light emitting element, and a wide wavelength range. An object of the present invention is to provide a highly efficient and long-life light emitting element that emits light in the near infrared region in the region, a light emitting device, a light source, an authentication device, and an electronic device provided with the light emitting element.

Such an object is achieved by the following invention.
The compound of the present invention (benzo-bis-thiadiazole-based compound) is characterized by being represented by the following general formula IRD.

［前記一般式ＩＲＤ中、基Ｘは、芳香族環を含む炭素数１〜２０の置換基であり、基Ｙは、芳香族環を含む炭素数１〜２０の置換基であり、各基Ｚ_１、Ｚ_２は、双方がカルバゾール基、または、一方がカルバゾール基および他方がジフェニルアミン基のうちのいずれかであり、各基Ｒ_１、Ｒ_２は、双方が水素原子、または、一方が水素原子および他方がカルバゾール基もしくはジフェニルアミン基のうちのいずれかである。］

[In the general formula IRD, the group X is a substituent having 1 to 20 carbon atoms including an aromatic ring, and the group Y is a substituent having 1 to 20 carbon atoms including an aromatic ring, and each group Z ₁ and Z ₂ are both carbazole groups, or one is either a carbazole group and the other is a diphenylamine group, and each group R ₁ and R ₂ are both hydrogen atoms or one hydrogen atom. And the other is either a carbazole group or a diphenylamine group. ]

By using the compound represented by the general formula IRD (benzo-bis-thiadiazole-based compound) as a light emitting material contained in the light emitting layer included in the light emitting element, the light emitting element can be specifically in the near infrared region in a wide wavelength region. It is possible to emit light with high efficiency in the emission peak wavelength region of 870 nm or more and 1020 nm or less.

The compound for a light emitting device (benzo-bis-thiadiazole-based compound) of the present invention is characterized by being represented by the following general formula IRD.

［前記一般式ＩＲＤ中、基Ｘは、芳香族環を含む炭素数１〜２０の置換基であり、基Ｙは、芳香族環を含む炭素数１〜２０の置換基であり、各基Ｚ_１、Ｚ_２は、双方がカルバゾール基、または、一方がカルバゾール基および他方がジフェニルアミン基のうちのいずれかであり、各基Ｒ_１、Ｒ_２は、双方が水素原子、または、一方が水素原子および他方がカルバゾール基もしくはジフェニルアミン基のうちのいずれかである。］

[In the general formula IRD, the group X is a substituent having 1 to 20 carbon atoms including an aromatic ring, and the group Y is a substituent having 1 to 20 carbon atoms including an aromatic ring, and each group Z ₁ and Z ₂ are both carbazole groups, or one is either a carbazole group and the other is a diphenylamine group, and each group R ₁ and R ₂ are both hydrogen atoms or one hydrogen atom. And the other is either a carbazole group or a diphenylamine group. ]

By using the compound for a light emitting element (benzo-bis-thiadiazole-based compound) represented by the general formula IRD as a light emitting material contained in the light emitting layer included in the light emitting element, this light emitting element has a near infrared region in a wide wavelength region. Specifically, it is possible to emit light with high efficiency in the emission peak wavelength region of 870 nm or more and 1020 nm or less.

The light emitting device of the present invention includes an anode and
With the cathode
It has a light emitting layer provided between the anode and the cathode and emitting light when energized between the anode and the cathode.
The light emitting layer is characterized by containing a compound represented by the following general formula IRD as a light emitting material.

［前記一般式ＩＲＤ中、基Ｘは、芳香族環を含む炭素数１〜２０の置換基であり、基Ｙは、芳香族環を含む炭素数１〜２０の置換基であり、各基Ｚ_１、Ｚ_２は、双方がカルバゾール基、または、一方がカルバゾール基および他方がジフェニルアミン基のうちのいずれかであり、各基Ｒ_１、Ｒ_２は、双方が水素原子、または、一方が水素原子および他方がカルバゾール基もしくはジフェニルアミン基のうちのいずれかである。］

[In the general formula IRD, the group X is a substituent having 1 to 20 carbon atoms including an aromatic ring, and the group Y is a substituent having 1 to 20 carbon atoms including an aromatic ring, and each group Z ₁ and Z ₂ are both carbazole groups, or one is either a carbazole group and the other is a diphenylamine group, and each group R ₁ and R ₂ are both hydrogen atoms or one hydrogen atom. And the other is either a carbazole group or a diphenylamine group. ]

According to the light emitting device configured in this way, since the compound represented by the general formula IRD (benzo-bis-thiadiazole-based compound) is used as the light emitting material, the near infrared region in a wide wavelength region, specifically, , A light emitting element capable of emitting light with high efficiency in the emission peak wavelength region of 870 nm or more and 1020 nm or less can be obtained.

The light emitting device of the present invention is preferably composed of a compound (tetracene-based material) represented by the following formula IRH1 as a host material for holding the light emitting material.

［前記式ＩＲＨ１中、ｎは、１〜１２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。］

[In the above formula IRH1, n represents a natural number of 1 to 12, and R represents an aryl group and an arylamino group which may independently have a hydrogen atom, an alkyl group and a substituent, respectively. ]

Since a tetracene-based material is used as the host material, energy can be efficiently transferred from the host material to the light emitting material. Therefore, the luminous efficiency of the light emitting element can be made excellent.

Further, since the tetracene-based material is excellent in stability (resistance) to electrons and holes, it is possible to extend the life of the light emitting layer and, by extension, the life of the light emitting element.

The light emitting device of the present invention is preferably composed of a compound (anthracene-based material) represented by the following formula IRH2 as a host material for holding the light emitting material.

［前記式ＩＲＨ２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。］

[In the above formula IRH2, n represents a natural number of 1 to 10, and R represents an aryl group and an arylamino group which may independently have a hydrogen atom, an alkyl group and a substituent, respectively. ]

Since an anthracene-based material is used as the host material, energy can be efficiently transferred from the host material to the luminescent material. Therefore, the luminous efficiency of the light emitting element can be made excellent.

Further, since the anthracene-based material is excellent in stability (resistance) to electrons and holes, it is possible to extend the life of the light emitting layer and, by extension, the life of the light emitting element.

In the light emitting device of the present invention, the host material is preferably composed of carbon atoms and hydrogen atoms.

As a result, it is possible to prevent an undesired interaction between the host material and the light emitting material from occurring. Therefore, the luminous efficiency of the light emitting element can be increased. It can also increase the resistance of the host material to potentials and holes. Therefore, the life of the light emitting element can be extended.

In the light emitting device of the present invention, the content of the light emitting material in the light emitting layer is preferably 0.5 wt% or more and 5.0 wt% or less.

As a result, the balance between the luminous efficiency and the life of the light emitting element can be improved.

The light emitting device of the present invention preferably includes an electron transport layer provided between the light emitting layer and the cathode and composed of a compound having an anthracene skeleton.

As a result, electrons can be efficiently transported and injected into the light emitting layer. As a result, the luminous efficiency of the light emitting element can be improved and the durability can be improved.

In the light emitting device of the present invention, the thickness of the light emitting layer is preferably 10 nm or more and 50 nm or less.

As a result, the life of the light emitting element can be extended while suppressing the driving voltage of the light emitting element.

The light emitting device of the present invention is characterized by including the light emitting element of the present invention.
Such a light emitting device can emit light in the near infrared region. Further, since it is provided with a light emitting element having high efficiency and long life, it is excellent in reliability.

The light source of the present invention is characterized by including the light emitting element of the present invention.
Such a light source can emit light in the near infrared region. Further, since it is provided with a light emitting element having high efficiency and long life, it is excellent in reliability.

The authentication device of the present invention is characterized by including the light emitting element of the present invention.
Such an authentication device can perform biometric authentication using near infrared light. Further, since it is provided with a light emitting element having high efficiency and long life, it is excellent in reliability.

The electronic device of the present invention is characterized by comprising the light emitting element of the present invention.
Such an electronic device is excellent in reliability because it includes a light emitting element having high efficiency and long life.

It is sectional drawing which shows typically the light emitting element which concerns on embodiment of this invention. It is a vertical sectional view which shows the embodiment of the display device to which the light emitting device of this invention is applied. It is a figure which shows the embodiment of the authentication apparatus of this invention. It is a perspective view which shows the structure of the mobile type (or notebook type) personal computer which applied the electronic device of this invention.

Hereinafter, preferred embodiments of the compound of the present invention, a compound for a light emitting element, a light emitting element, a light emitting device, a light source, a certification device, and an electronic device will be described in 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, for convenience of explanation, the upper side in FIG. 1 will be referred to as “upper” and the lower side will be referred to as “lower”.

In the present embodiment, the light emitting element (electroluminescence element) 1 includes an anode 3, a hole injection layer 4, a light emitting layer 5, an electron transport layer 6, an electron injection layer 7, and a cathode 8 as shown in FIG. It is laminated in order. That is, in the light emitting element 1, the hole injection layer 4, the light emitting layer 5, the electron transport layer 6, and the electron injection layer 7 are laminated in this order between the anode 3 and the cathode 8 from the anode 3 side to the cathode 8 side. The laminated body 14 is inserted.

The light emitting element 1 is entirely provided on the substrate 2 and is sealed by the sealing member 9.

Such a light emitting element 1 has an anode 3 and a cathode 8 and a light emitting layer 5 provided between them, and a driving voltage is applied to the anode 3 and the cathode 8 to apply a driving voltage to the anode 3 and the cathode 8. In other words, when the light emitting layer 5 is energized, electrons are supplied (injected) from the cathode 8 side and holes are supplied (injected) from the anode 3 side to the light emitting layer 5, respectively. .. Then, in the light emitting layer 5, holes and electrons are recombined, and excitons (excitons) are generated by the energy released at the time of this recombination, and energy (fluorescence or phosphorescence) is generated when the excitons return to the ground state. Is emitted (light emission). As a result, the light emitting element 1 (light emitting layer 5) emits light.

In particular, the light emitting element 1 is a compound of the present invention (a compound for a light emitting element as a preferable example) as a light emitting material of the light emitting layer 5 as described later, that is, a benzo-bis-thiazol-based compound represented by the general formula IRD described later. By using the above, light is emitted with high efficiency in the near infrared region in a wide wavelength region, specifically, in the emission peak wavelength region of 870 nm or more and 1020 nm or less. In the present specification, the “near infrared region” refers to a wavelength region of 700 nm or more and 1500 nm or less.

The substrate 2 supports the anode 3. Since the light emitting element 1 of the present embodiment has a configuration (bottom emission type) in which light is extracted from the substrate 2 side, the substrate 2 and the anode 3 are substantially transparent (colorless transparent, colored transparent or translucent), respectively. Has been done.

Examples of the constituent material of the substrate 2 include resin materials such as polyethylene terephthalate, polyethylene naphthalate, polypropylene, cycloolefin polymer, polyamide, polyether sulfone, polymethylmethacrylate, polycarbonate, and polyarylate, quartz glass, and soda glass. Examples of glass materials such as the above, and one or a combination of two or more of these can be used.

The average thickness of such a substrate 2 is not particularly limited, but is preferably about 0.1 mm or more and 30 mm or less, and more preferably about 0.1 mm or more and 10 mm or less.

When the light emitting element 1 has a configuration in which light is extracted from the side opposite to the substrate 2 (top emission type), either a transparent substrate or an opaque substrate can be used for the substrate 2.

Examples of the opaque substrate include a substrate made of a ceramic material such as alumina, a metal substrate such as stainless steel having an oxide film (insulating film) formed on the surface, and a substrate made of a resin material. Be done.

Further, in such a light emitting element 1, the distance between the anode 3 and the cathode 8 (that is, the average thickness of the laminated body 14) is preferably 100 nm or more and 500 nm or less, and more preferably 100 nm or more and 300 nm or less. More preferably, it is 100 nm or more and 250 nm or less. As a result, the drive voltage of the light emitting element 1 can be easily and surely within a practical range.

Hereinafter, each part constituting the light emitting element 1 will be described in sequence.
(anode)
The anode 3 is an electrode for injecting holes into the hole injection layer 4. As the 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 ₂ O ₃ , SnO ₂ , Sb-containing SnO ₂ , and Al-containing ZnO, Au, Pt, and Ag. , Cu, alloys containing these, and the like, and one or a combination of two or more of these can be used.

In particular, the anode 3 is preferably made of ITO. ITO is a material having transparency, a large work function, and excellent conductivity. As a result, holes can be efficiently injected from the anode 3 into the hole injection layer 4.

Further, it is preferable that the surface of the anode 3 on the hole injection layer 4 side (upper surface in FIG. 1) is subjected to plasma treatment. This makes it possible to enhance the chemical and mechanical stability of the joint surface between the anode 3 and the hole injection layer 4. As a result, the hole injection property from the anode 3 to the hole injection layer 4 can be improved. The 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 such an anode 3 is not particularly limited, but is preferably about 10 nm or more and 200 nm or less, and more preferably about 50 nm or more and 150 nm or less.

(cathode)
On the other hand, the cathode 8 is an electrode for injecting electrons into the electron transport layer 6 via the electron injection layer 7 described later. As the constituent material of the cathode 8, it is preferable to use a material having a small work function.

Examples of the constituent material of the cathode 8 include Li, Mg, Ca, Sr, La, Ce, Er, Eu, Sc, Y, Yb, Ag, Cu, Al, Cs, Rb, and alloys containing these. , One or two or more of these can be used in combination (for example, as a laminate of a plurality of layers, a mixed layer of a plurality of types, etc.).

In particular, when an alloy is used as the constituent material of the cathode 8, 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 a constituent material of the cathode 8, it is possible to improve the electron injection efficiency and stability of the cathode 8.

The average thickness of such a cathode 8 is not particularly limited, but is preferably about 100 nm or more and 10000 nm or less, and more preferably about 100 nm or more and 500 nm or less.

Since the light emitting element 1 of the present embodiment is a bottom emission type, the cathode 8 is not particularly required to have light transmission. Further, in the case of the top emission type, since it is necessary to transmit light from the cathode 8 side, the average thickness of the cathode 8 is preferably about 1 nm or more and 50 nm or less.

(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). As a result, the luminous efficiency of the light emitting element 1 can be increased. Here, the hole injection layer 4 also has a function of transporting the holes injected from the anode 3 to the light emitting layer 5 (that is, has a hole transporting property). Therefore, the hole injection layer 4 can be said to be a hole transport layer because it has a hole transport property as described above. A hole transport layer made of a material different from that of the hole injection layer 4 (for example, an amine compound such as a benzidine derivative) may be separately provided between the hole injection layer 4 and the light emitting layer 5.

The hole injection layer 4 contains a material having a hole injection property (hole injection material).
The hole-injecting material contained in the hole-injecting layer 4 is not particularly limited, and for example, copper phthalocyanine or 4,4', 4''-tris (N, N-phenyl-3-methylphenylamino). ) Amine-based materials such as triphenylamine (m-MTDATA), N, N'-bis- (4-diphenylamino-phenyl) -N, N'-diphenyl-biphenyl-4-4'-diamine can be 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 and a benzidine derivative (benzidine) are preferable. A material having a skeleton), a triamine compound having both a "diaminobenzene" unit and a "benzidine" unit in the molecule, and a tetraamine compound (specifically, for example, represented by the following formulas HIL-1 to HIL-27). It is more preferable to use a compound as such.

Further, the LUMO of the constituent material of the hole injection layer 4 preferably has a difference of 0.5 eV or more from the LUMO of the host material used for the light emitting layer 5. As a result, it is possible to reduce the escape of electrons from the light emitting layer 5 to the hole injection layer 4 and improve the luminous efficiency.

The HOMO of the constituent material of the hole injection layer 4 is preferably 4.7 eV or more and 5.8 eV or less, and the LUMO of the constituent material of the hole injection layer 4 is 2.2 eV or more and 3.0 eV or less. Is preferable.

The average thickness of such a hole injection layer 4 is not particularly limited, but is preferably about 5 nm or more and 90 nm or less, and more preferably about 10 nm or more and 70 nm or less.

(Light emitting layer)
The light emitting layer 5 emits light by energizing between the anode 3 and the cathode 8 described above.

The light emitting layer 5 is configured to include a light emitting material. In the present invention, the light emitting layer 5 is a benzo-bis-thiadiazole-based compound represented by the following general formula IRD (hereinafter, simply "benzo-bis-thiadiazole-based compound), which is a compound of the present invention (compound for a light emitting element) as a light emitting material. also referred to as compound ") i.e., one benzo - bis - thiadiazole and skeleton, a compound having two or three carbazole skeleton or diphenylamine skeleton (except group Z _1, and the group Z ₂ is a diphenylamine skeleton together) Is configured to include.

［前記一般式ＩＲＤ中、基Ｘは、芳香族環を含む炭素数１〜２０の置換基であり、基Ｙは、芳香族環を含む炭素数１〜２０の置換基であり、各基Ｚ_１、Ｚ_２は、双方がカルバゾール基、または、一方がカルバゾール基および他方がジフェニルアミン基のうちのいずれかであり、各基Ｒ_１、Ｒ_２は、双方が水素原子、または、一方が水素原子および他方がカルバゾール基もしくはジフェニルアミン基のうちのいずれかである。］

[In the general formula IRD, the group X is a substituent having 1 to 20 carbon atoms including an aromatic ring, and the group Y is a substituent having 1 to 20 carbon atoms including an aromatic ring, and each group Z ₁ and Z ₂ are both carbazole groups, or one is either a carbazole group and the other is a diphenylamine group, and each group R ₁ and R ₂ are both hydrogen atoms or one hydrogen atom. And the other is either a carbazole group or a diphenylamine group. ]

In the present invention, in the general formula IRD, each of the groups Z ₁ and Z ₂ is either a carbazole group, or one is a carbazole group and the other is a diphenylamine group. That is, in the combination of the carbazole group and the diphenylamine group, the case where both are diphenylamine groups is excluded. Therefore, the general formula IRD can be represented by the following general formula IRD-A, the following general formula IRD-B, or the benzo-bis-thiadiazole-based compound represented by the following general formula IRD-C.

［前記一般式ＩＲＤ−Ａ中、基Ｘは、芳香族環を含む炭素数１〜２０の置換基であり、基Ｙは、芳香族環を含む炭素数１〜２０の置換基であり、各基Ｒ_１、Ｒ_２は、双方が水素原子、または、一方が水素原子および他方がカルバゾール基もしくはジフェニルアミン基のうちのいずれかである。］

[In the general formula IRD-A, the group X is a substituent having 1 to 20 carbon atoms including an aromatic ring, and the group Y is a substituent having 1 to 20 carbon atoms including an aromatic ring. The groups R ₁ and R ₂ are both hydrogen atoms, or one is a hydrogen atom and the other is a carbazole group or a diphenylamine group. ]

［前記一般式ＩＲＤ−Ｂ中、基Ｘは、芳香族環を含む炭素数１〜２０の置換基であり、基Ｙは、芳香族環を含む炭素数１〜２０の置換基であり、各基Ｒ_１、Ｒ_２は、双方が水素原子、または、一方が水素原子および他方がカルバゾール基もしくはジフェニルアミン基のうちのいずれかである。］

[In the general formula IRD-B, the group X is a substituent having 1 to 20 carbon atoms including an aromatic ring, and the group Y is a substituent having 1 to 20 carbon atoms including an aromatic ring. The groups R ₁ and R ₂ are both hydrogen atoms, or one is a hydrogen atom and the other is a carbazole group or a diphenylamine group. ]

［前記一般式ＩＲＤ−Ｃ中、基Ｘは、芳香族環を含む炭素数１〜２０の置換基であり、基Ｙは、芳香族環を含む炭素数１〜２０の置換基であり、各基Ｒ_１、Ｒ_２は、双方が水素原子、または、一方が水素原子および他方がカルバゾール基もしくはジフェニルアミン基のうちのいずれかである。］

[In the general formula IRD-C, the group X is a substituent having 1 to 20 carbon atoms including an aromatic ring, and the group Y is a substituent having 1 to 20 carbon atoms including an aromatic ring. The groups R ₁ and R ₂ are both hydrogen atoms, or one is a hydrogen atom and the other is a carbazole group or a diphenylamine group. ]

Further, in the general formula IRD (the general formula IRD-A, the general formula IRD-B, the general formula IRD-C), both of the groups R ₁ and R ₂ are hydrogen atoms, or one is a hydrogen atom. And the other is either a carbazole group or a diphenylamine group. That is, in the combination of a hydrogen atom and a carbazole group or a diphenylamine group, both are carbazole groups, both are diphenylamine groups, and one is a carbazole group and the other is a diphenylamine group. Therefore, the general formula IRD-A can be represented by the benzo-bis-thiadiazole-based compounds represented by the following general formulas IRD-AI to the following general formula IRD-AV, and the general formula IRD-B is , The following general formula IRD-BI to the following general formula IRD-B-V can be represented by the benzo-bis-thiadiazole-based compound, and the general formula IRD-C is the following general formula IRD-C-I. It can be represented by a benzo-bis-thiadiazole-based compound represented by the following general formula IRD-C-IV.

［前記一般式ＩＲＤ−Ａ−Ｉ〜前記一般式ＩＲＤ−Ａ−Ｖ中、基Ｘは、芳香族環を含む炭素数１〜２０の置換基であり、基Ｙは、芳香族環を含む炭素数１〜２０の置換基である。］

[In the general formula IRD-AI to the general formula IRD-AV, the group X is a substituent having 1 to 20 carbon atoms including an aromatic ring, and the group Y is a carbon containing an aromatic ring. It is a substituent of the number 1 to 20. ]

［前記一般式ＩＲＤ−Ｂ−Ｉ〜前記一般式ＩＲＤ−Ｂ−Ｖ中、基Ｘは、芳香族環を含む炭素数１〜２０の置換基であり、基Ｙは、芳香族環を含む炭素数１〜２０の置換基である。］

[In the general formula IRD-BI to the general formula IRD-B-V, the group X is a substituent having 1 to 20 carbon atoms including an aromatic ring, and the group Y is a carbon containing an aromatic ring. It is a substituent of the number 1 to 20. ]

［前記一般式ＩＲＤ−Ｃ−Ｉ〜前記一般式ＩＲＤ−Ｃ−IV中、基Ｘは、芳香族環を含む炭素数１〜２０の置換基であり、基Ｙは、芳香族環を含む炭素数１〜２０の置換基である。］

[In the general formula IRD-C-I to the general formula IRD-C-IV, the group X is a substituent having 1 to 20 carbon atoms including an aromatic ring, and the group Y is a carbon containing an aromatic ring. It is a substituent of the number 1 to 20. ]

Further, in the general formula IRD (the general formula IRD-A (-I to V), the general formula IRD-B (-I to V) and the general formula IRD-C (-I to IV)), the group X Is a substituent having 1 to 20 carbon atoms including an aromatic ring, and the aromatic ring is composed of a carbon atom alone, or the aromatic ring is composed of a carbon atom and a sulfur atom. Specific examples thereof include those represented by the following chemical formulas X1 to X5.

Here, in Formula X1~ Formula X5, bond on the left side is the group _{Z 1} in the general formula IRD, Formula IRD-A (-I~V), the formula IRD-B ( -I-V) and the bonder located on the right side connected to the nitrogen atom adjacent to the group X in the general formula IRD-C (-I to IV) is the general formula IRD (the general formula IRD-A). (-I-V), the general formula IRD-B (-I-V) and the general formula IRD-C (-I-IV)) are linked to a carbon atom adjacent to the group X.

Further, in the general formula IRD (the general formula IRD-A (-I to V), the general formula IRD-B (-I to V) and the general formula IRD-C (-I to IV)), the base Y Is a substituent having 1 to 20 carbon atoms including an aromatic ring, but the aromatic ring is composed of a carbon atom alone, the aromatic ring is composed of a carbon atom and a sulfur atom, and the aromatic ring. It is preferable that the ring is composed of a carbon atom and a nitrogen atom, or that the aromatic ring is linked via a nitrogen atom (phenylamine structure). Specifically, for example, the following chemical formula Y1 ~ The one represented by the chemical formula Y11 can be mentioned.

The compounds represented by the general formulas IRD-AI to V, the general formulas IRD-B-I to V, and the general formulas IRD-C-I to IV are configured to include groups X and Y having such a constitution. with things, these compounds, those carbazole group or a diphenylamine group functions as an electron donor linked two or three (except group Z _1, and the group Z ₂ is a diphenylamine skeleton together) , i.e., the dimer or trimer of a combination of a carbazole group and diphenylamine groups functions as an electron donor (except group Z _1, and the group Z ₂ is a diphenylamine skeleton together), via a group X, It has a structure in which one benzo-bis-thiazol skeleton that functions as an electron acceptor is linked with a group Y. By combining such an electron acceptor and an electron donor, the band gap in the compound is narrowed, and the light emitting layer 5 containing this benzo-bis-thiadiazole-based compound as a light emitting dopant in the light emitting material is highly efficient near red. It can be assumed that light emission in the outer region is realized. Further, the light emitting layer 5 containing this benzo-bis-thiadiazole compound as a light emitting dopant in a light emitting material is capable of emitting light in a wide wavelength range in a wavelength range of 700 nm or more (near infrared range), specifically, It is possible to emit light in the emission peak wavelength range of 870 nm or more and 1020 nm or less.

In particular, the group X contains a sulfur atom in the aromatic ring as in the chemical formulas X2 to X4, and the group Y contains a sulfur atom in the aromatic ring as in the chemical formulas Y4 and Y5. When at least one of the compounds is used as a benzo-bis-thiadiazole-based compound, the light emitting layer 5 containing this as a light emitting dopant is capable of emitting light particularly in a long wavelength region, specifically, about 895 nm or more and 1020 nm or less. It is possible to emit light in the emission peak wavelength range of. In addition, such a tendency is more remarkable when the above-mentioned ones are used for both the group X and the group Y.

Further, when a group containing a nitrogen atom as the group Y is used as the benzo-bis-thiadiazole compound as in the chemical formulas Y6 to Y11, the light emitting layer 5 containing this as a light emitting dopant is excellent in light emission. It will be able to emit light with efficiency.

Specific examples of the benzo-bis-thiadiazole-based compound represented by the above formula IRD-AI having each group X and group Y as described above include the chemical formula X1 to the chemical formula X5 of the group X. Examples of the combination of the group Y with the chemical formula Y1 to the chemical formula Y11 include a compound represented by the following formula IRD-A1 to the following formula IRD-A55 or a derivative thereof.

Further, as the benzo-bis-thiazol-based compound represented by the above formula IRD-A-II having each group X and group Y as described above, specifically, the chemical formula X1 to the chemical formula X5 of the group X. And the compound represented by the following formula IRD-A56 to the following formula IRD-A110 or a derivative thereof can be mentioned as a combination of the group Y with the chemical formula Y1 to the chemical formula Y11.

Further, as the benzo-bis-thiadiazole-based compound represented by the above formula IRD-A-III having each group X and group Y as described above, specifically, the chemical formula X1 to the chemical formula X5 of the group X. As a combination of the group Y with the chemical formula Y1 to the chemical formula Y11, a compound represented by the following formula IRD-A111 to the following formula IRD-A165 or a derivative thereof can be mentioned.

Further, as the benzo-bis-thiadiazole-based compound represented by the above formula IRD-A-IV having each group X and group Y as described above, specifically, the chemical formula X1 to the chemical formula X5 of the group X. And the compound represented by the following formula IRD-A166 to the following formula IRD-A220 or a derivative thereof can be mentioned as a combination of the group Y with the chemical formula Y1 to the chemical formula Y11.

Further, as the benzo-bis-thiadiazole-based compound represented by the above formula IRD-AV having each group X and group Y as described above, specifically, the chemical formula X1 to the chemical formula X5 of the group X. As a combination of the group Y with the chemical formula Y1 to the chemical formula Y11, a compound represented by the following formula IRD-A221 to the following formula IRD-A275 or a derivative thereof can be mentioned.

Further, as the benzo-bis-thiadiazole-based compound represented by the above formula IRD-BI having each group X and group Y as described above, specifically, the chemical formula X1 to the chemical formula X5 of the group X. As a combination of the group Y with the chemical formula Y1 to the chemical formula Y11, a compound represented by the following formula IRD-B1 to the following formula IRD-B55 or a derivative thereof can be mentioned.

Further, as the benzo-bis-thiadiazole-based compound represented by the above formula IRD-B-II having each group X and group Y as described above, specifically, the chemical formula X1 to the chemical formula X5 of the group X. And the compound represented by the following formula IRD-B56 to the following formula IRD-B110 or a derivative thereof can be mentioned as a combination of the group Y with the chemical formula Y1 to the chemical formula Y11.

Further, as the benzo-bis-thiadiazole-based compound represented by the above formula IRD-BIII having each group X and group Y as described above, specifically, the chemical formula X1 to the chemical formula X5 of the group X Examples of the combination of the group Y with the chemical formula Y1 to the chemical formula Y11 include a compound represented by the following formula IRD-B111 to the following formula IRD-B165 or a derivative thereof.

Further, as the benzo-bis-thiadiazole-based compound represented by the above formula IRD-B-IV having each group X and group Y as described above, specifically, the chemical formula X1 to the chemical formula X5 of the group X. And the compound represented by the following formula IRD-B166 to the following formula IRD-B220 or a derivative thereof can be mentioned as a combination of the group Y with the chemical formula Y1 to the chemical formula Y11.

Further, as the benzo-bis-thiadiazole-based compound represented by the above formula IRD-BV having each group X and the group Y as described above, specifically, the chemical formula X1 to the chemical formula X5 of the group X. As a combination of the group Y with the chemical formula Y1 to the chemical formula Y11, a compound represented by the following formula IRD-B221 to the following formula IRD-B275 or a derivative thereof can be mentioned.

Further, as the benzo-bis-thiadiazole-based compound represented by the above formula IRD-C-I having each group X and group Y as described above, specifically, the chemical formula X1 to the chemical formula X5 of the group X. As a combination of the group Y with the chemical formula Y1 to the chemical formula Y11, a compound represented by the following formula IRD-C1 to the following formula IRD-C55 or a derivative thereof can be mentioned.

Further, as the benzo-bis-thiadiazole-based compound represented by the above formula IRD-C-II having each group X and group Y as described above, specifically, the chemical formula X1 to the chemical formula X5 of the group X. And the compound represented by the following formula IRD-C56 to the following formula IRD-C110 or a derivative thereof can be mentioned as a combination of the group Y with the chemical formula Y1 to the chemical formula Y11.

Further, as the benzo-bis-thiadiazole-based compound represented by the above formula IRD-C-III having each group X and group Y as described above, specifically, the chemical formula X1 to the chemical formula X5 of the group X. As a combination of the group Y with the chemical formula Y1 to the chemical formula Y11, a compound represented by the following formula IRD-C111 to the following formula IRD-C165 or a derivative thereof can be mentioned.

Further, as the benzo-bis-thiadiazole-based compound represented by the above formula IRD-C-IV having each group X and group Y as described above, specifically, the chemical formula X1 to the chemical formula X5 of the group X. And the compound represented by the following formula IRD-C166 to the following formula IRD-C220 or a derivative thereof can be mentioned as a combination of the group Y with the chemical formula Y1 to the chemical formula Y11.

The light emitting layer 5 may contain a light emitting material (various fluorescent materials, various phosphorescent materials) other than the above-mentioned light emitting material.

Further, in the present embodiment, the light emitting layer 5 is preferably configured to include a host material to which the light emitting material is added (supported) as a guest material (dopant) in addition to the light emitting material as described above. .. This host material has the function of recombining holes and electrons to generate excitons and transferring the energy of the excitons to the light emitting material (Felster movement or Dexter movement) to excite the light emitting material. Have. Therefore, the luminous efficiency of the light emitting element 1 can be improved by forming the light emitting layer 5 so as to contain the host material in addition to the light emitting material (guest material). Such a host material can be used, for example, by doping the host material with a light emitting material which is a guest material as a dopant.

Such a host material is not particularly limited as long as it exhibits the above-mentioned functions with respect to the guest material to be used, but for example, an acene-based material such as a distyrylarylene derivative, a naphthacene derivative, or an anthracene derivative. Kinolinolato such as perylene derivative, distyrylbenzene derivative, distyrylamine derivative, bis (2-methyl-8-quinolinolato) (p-phenylphenolato) aluminum (BAlq), tris (8-quinolinolato) aluminum complex (Alq ₃ ) Triarylamine derivatives such as system metal complexes and tetramers of triphenylamine, oxadiazole derivatives, rubrene and its derivatives, silol derivatives, dicarbazole derivatives, oligothiophene derivatives, benzopyran derivatives, triazole derivatives, benzoxazole derivatives, benzo Thiazol derivative, quinoline derivative, 4,4'-bis (2,2'-diphenylvinyl) biphenyl (DPVBi), 3-phenyl-4- (1'-naphthyl) -5-phenylcarbazole, 4,4'-N , N'-Dicarbazolebiphenyl (CBP) and other carbazole derivatives can be mentioned, and one of them can be used alone or in combination of two or more.

Among these, as the host material, it is preferable to use an acene-based material or a quinolinolato-based metal complex, and it is more preferable to use an acene-based material.

The acene-based material has less unintentional interaction with the guest material as described above. Further, when an acene-based material (particularly anthracene-based material or tetracene-based material) is used as the host material, energy can be efficiently transferred from the host material to the guest material (light emitting material), and therefore, the light emitting element 1 can be subjected to energy transfer. The luminous efficiency can be made excellent. This means that (a) it is possible to generate a singlet excited state of the guest material by energy transfer from the triplet excited state of the ascene material, and (b) the π electron cloud of the asen material and the electron cloud of the guest material. It is considered that this is due to the fact that the overlap with is large.

For this reason, when an acene-based material is used as the host material, the luminous efficiency of the light emitting element 1 can be improved.

In addition, acene-based materials have excellent resistance to electrons and holes. In addition, the acene-based material is also excellent in thermal stability. Therefore, the life of the light emitting layer 5 and thus the light emitting element 1 can be extended. Further, since the acene-based material is excellent in thermal stability, it is possible to prevent decomposition of the host material due to heat during film formation when the light emitting layer is formed by using the vapor phase film forming method. Therefore, a light emitting layer having an excellent film quality can be formed, and as a result, the luminous efficiency of the light emitting element 1 can be improved and the life can be extended in this respect as well.

Further, since the acene-based material itself does not easily emit light, it is possible to prevent the host material 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 above-mentioned effects, and is, for example, a naphthalene derivative, an anthracene derivative, naphthacene derivative (tetracene derivative), or pentacene. Derivatives can be mentioned, and one or a combination of two or more of these can be used, but it is preferable to use an anthracene-based material (anthracene derivative) or a tetracene-based material (tetracene derivative), and a tetracene-based material is used. Is more preferable.

The tetracene-based material is not particularly limited as long as it has at least one tetracene skeleton in one molecule and can exhibit the function as a host material as described above. For example, the following formula IRH1 It is preferable to use the compound represented by.

［前記式ＩＲＨ１中、ｎは、１〜１２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。］

[In the above formula IRH1, n represents a natural number of 1 to 12, and R represents an aryl group and an arylamino group which may independently have a hydrogen atom, an alkyl group and a substituent, respectively. ]

Since the benzo-bis-thiadiazole compound as described above has high polarity (large polarization), when it is used as a light emitting material, it emits light due to the interaction between the molecules of the light emitting material when the concentration in the light emitting layer is high. Concentration quenching, which is a phenomenon of reduced efficiency, is likely to occur.

On the other hand, the tetracene-based material has low polarity (small polarity). Therefore, by using the tetracene-based material as the host material, it is possible to reduce the interaction between the molecules of the light emitting material as described above and reduce the concentration quenching property.

On the other hand, for example, when Alq ₃ having a high polarity (large polarization) is used as the host material, both the host material and the light emitting material have high polarities (large polarization), so that the molecules of the light emitting material interact with each other. The action is likely to occur, and the concentration quenching property becomes high.

Further, the anthracene-based material, which is the same asene-based material as the tetracene-based material, has an effect of reducing the concentration quenching property when used as the host material, but emits light as compared with the case where the tetracene-based material is used as the host material. It is less efficient. This is because when an anthracene-based material is used as the host material, the energy transfer from the host material to the light-emitting material is insufficient, and the electrons injected into the LUMO of the host material have a high probability of penetrating toward the anode side. It is presumed that there is. Considering this point, when comparing the anthracene-based material and the tetracene-based material, the tetracene-based material is particularly preferably used as the host material.

Therefore, by using a tetracene-based material (acene-based material) as the host material, the luminous efficiency of the light emitting element 1 can be increased.

In addition, the tetracene-based material has excellent resistance to electrons and holes. In addition, the tetracene-based material is also excellent in thermal stability. Therefore, the life of the light emitting element 1 can be extended. Further, since the tetracene-based material is excellent in thermal stability, it is possible to prevent decomposition of the host material due to heat during film formation when the light emitting layer is formed by using the vapor phase film forming method. Therefore, a light emitting layer having an excellent film quality can be formed, and as a result, the luminous efficiency of the light emitting element 1 can be improved and the life can be extended in this respect as well.

Further, since the tetracene-based material itself does not easily emit light, it is possible to prevent the host material from adversely affecting the emission spectrum of the light emitting element 1.

The tetracene-based material used as the host material is not particularly limited as long as it is represented by the above formula IRH1 and can exhibit the function as the host material as described above, but the following formula IRH1-A can be used. It is preferable to use the compound represented by this, and it is more preferable to use the compound represented by IRH1-B below.

［前記式ＩＲＨ１−Ａ、ＩＲＨ１−Ｂ中、Ｒ_１〜Ｒ_４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_４は、互いに同じであっても異なっていてもよい。］

[Formula IRH1-A, in _IRH1-B, R 1 ~R ₄ are each independently a hydrogen atom, an alkyl group, an aryl group which may have a substituent group, an arylamino group. Further, R _{1 to} R ₄ may be the same as or different from each other. ]

Further, the tetracene-based material, that is, the host material is preferably composed of a carbon atom and a hydrogen atom. As a result, the polarity of the host material can be lowered, and an undesired interaction between the host material and the light emitting material can be prevented. Therefore, the luminous efficiency of the light emitting element 1 can be increased. It can also increase the resistance of the host material to potentials and holes. Therefore, the life of the light emitting element 1 can be extended.

Specifically, as the tetracene-based material, for example, it is preferable to use a compound represented by the following formulas IRH1-1 to IRH1-27.

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. A compound represented by the formula IRH2 is preferably used, and examples thereof include a compound represented by the following formula IRH2-A, the following formula IRH2-B, the following formula IRH2-C, or the following formula IRH2-D. More specifically, for example, a compound represented by the following formula IRH2-1 to 56 can be mentioned.

The HOMO of the host material used for the light emitting layer 5 is preferably 5.0 eV or more and 5.8 eV or less, and the LUMO of this host material is preferably 2.5 eV or more and 3.6 eV or less.

The content (doping amount) of the light emitting material in the light emitting layer 5 including such a light emitting material and the host material is preferably 0.5 wt% or more and 5.0 wt% or less, and 0.75 wt% or more and 2.0 wt%. % Or less is more preferable, and 1.5 wt% or more and 2.0 wt% or less is further preferable. When the content of the light emitting material is less than the lower limit value, the light emission from the host tends to be stronger depending on the type of the host material, and when the content exceeds the upper limit value, the luminous efficiency is lowered due to the concentration quenching depending on the type of the host material. Since it may show a remarkable tendency, the balance between the luminous efficiency and the life of the light emitting element 1 can be improved by setting the content of the light emitting material within the above range.

The average thickness of the light emitting layer 5 is preferably 10 nm or more and 50 nm or less, and more preferably 25 nm or more and 50 nm or less. If the average thickness of the light emitting layer 5 is less than the lower limit, the recombination in the peripheral layer of the light emitting layer 5 tends to increase depending on the type of the light emitting material, and unnecessary light emission may increase. Further, if the value exceeds the upper limit, the voltage in the light emitting layer 5 tends to gradually increase depending on the type of the light emitting material, which may lead to a decrease in the luminous efficiency of the light emitting layer 5. Therefore, the thickness of the light emitting layer 5 By setting the above range, it is possible to obtain the light emitting element 1 with high efficiency and long life while suppressing the driving voltage of the light emitting element 1.

In the present embodiment, the case where the compound for a light emitting element of the present invention is applied to a light emitting material included in the light emitting layer 5 has been described, but the compound for a light emitting element of the present invention is not limited to this, and the hole injection layer is not limited to this. It may be contained as a hole injection material included in 4 or an electron transport material included in the electron transport layer 6.

(Electronic transport layer)
The electron transport layer 6 has a function of transporting electrons injected from the cathode 8 through the electron injection layer 7 to the light emitting layer 5.

Examples of the constituent material (electron transporting material) of the electron transport layer 6 include a phenanthroline derivative such as 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), and tris (8-quinolinolato) aluminum. Kinolin derivatives such as 8-quinolinol such as (Alq ₃ ) or an organic metal complex having a derivative thereof as a ligand, azindidine derivative, oxadiazole derivative, perylene derivative, pyridine derivative, pyrimidine derivative, quinoxalin derivative, diphenylquinone Examples thereof include derivatives, nitro-substituted fluorene derivatives, acene-based materials such as anthracene-based materials, and one or a combination of two or more of these can be used.

Among these, as the electron transporting material used for the electron transporting layer 6, it is preferable to use a compound having an anthracene skeleton. Further, it is preferable to use a nitrogen-containing compound having a nitrogen atom in the skeleton, such as a phenanthroline derivative and a phenanthroline derivative. From these facts, it is particularly preferable to use an azaindlizine-based compound having both an azaindlizine skeleton and an anthracene skeleton in the molecule (hereinafter, also simply referred to as “azaindridine-based compound”). As a result, electrons can be efficiently transported and injected into the light emitting layer 5. As a result, the luminous efficiency of the light emitting element 1 can be increased.

Further, when the electron transport layer 6 is used in combination of two or more of the above-mentioned electron transport materials, the electron transport layer 6 may be composed of a mixed material in which two or more kinds of electron transport materials are mixed, or different. It may be configured by laminating a plurality of layers composed of an electron transporting material. In the present embodiment, as shown in FIG. 1, the electron transport layer 6 includes a first electron transport layer 6b and a second electron transport layer 6a provided between the first electron transport layer 6b and the light emitting layer 5. ,have.

The compound having an anthracene skeleton used as a constituent material of the first electron transport layer 6b is preferably an azaindlizine-based compound having both an azaindolizine skeleton and an anthracene skeleton in the molecule. Further, the compound having an anthracene skeleton used as a constituent material of the second electron transport layer 6a is preferably an anthracene-based compound having an anthracene skeleton in the molecule and composed of carbon atoms and hydrogen atoms. As a result, electrons can be efficiently transported and injected into the light emitting layer 5, and deterioration of the electron transport layer 6 can be reduced. As a result, the luminous efficiency of the light emitting element 1 can be improved and the life of the light emitting element 1 can be extended.

Here, it is possible to extend the life by reducing the thickness of the first electron transport layer 6b while ensuring the thickness of the electron transport layer 6 required for optical light extraction by the second electron transport layer 6a. it can.

The number of azaindridine skeletons and anthracene skeletons contained in one molecule of the azaindridine-based compound used in the electron transport layer 6 is preferably one or two, respectively. Thereby, the electron transport property and the electron injection property of the electron transport layer 6 can be made excellent.

Specifically, examples of the azaindlizine-based compound used in the electron transport layer 6 include, for example, a compound represented by the following formula ETL1-1 to 24, a compound represented by the following formula ETL1-25-36, and the following. It is preferable to use the compounds represented by the formulas ETL1-37 to 56.

Such an azindolizine-based compound is excellent in electron transportability and electron injection property. Therefore, the luminous efficiency of the light emitting element 1 can be improved.

It is considered that the excellent electron transporting property and electron injecting property of such azaindolizine compounds are due to the following reasons.

In the azaindridine-based compound having the azaindridine skeleton and the anthracene skeleton in the molecule as described above, the entire molecule is connected by a π-conjugated system, so that the electron cloud spreads over the entire molecule.

The azaindlizine skeleton portion of the azaindridine 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 anthracene skeleton portion of the azaindlizine compound has a function of accepting electrons from the azaindlizine skeleton portion and a layer adjacent to the anode 3 side of the electron transport layer 6, that is, a light emitting layer. It has a function of handing over to 5.

More specifically, the part of the azaindrin skeleton of such an azaindrin-based compound has two nitrogen atoms, and one of the nitrogen atoms (the side closer to the part of the anthracene skeleton) has an sp ² hybrid orbital. a nitrogen atom of the other (the side far from the portion of the anthracene skeleton) has a sp ³ hybrid orbital. Nitrogen atoms with sp ² hybrid orbitals form part of the conjugated system of molecules of azidolysin compounds, and accept electrons because they have higher electronegativity and higher electron-attracting strength than carbon atoms. Functions as a part. On the other hand, the nitrogen atom having an sp ³ hybrid orbital is not a normal conjugated system, because it has an unshared electron pair, functions that electrons as part for feeding the electrons toward the conjugated molecules of azaindolizine compounds To do.

On the other hand, since the anthracene skeleton portion of the azaindridine compound is electrically neutral, electrons can be easily accepted from the azaindlizine skeleton portion. Further, since the anthracene skeleton portion of the azaindridine compound has a large orbital overlap with the constituent material of the light emitting layer 5, particularly the host material (tetracene material), electrons are easily received by the host material of the light emitting layer 5. Can be passed.

Further, since such an azindolidin-based compound is excellent in electron transporting property and electron injecting property as described above, as a result, the driving voltage of the light emitting element 1 can be lowered.

Further, the portion of the azaindlizine skeleton is stable even when the nitrogen atom having the sp ² hybrid orbital is reduced, and is stable even when the nitrogen atom having the sp ³ hybrid orbital is oxidized. Therefore, such an azindolizine-based compound has high stability against electrons and holes. As a result, the life of the light emitting element 1 can be extended.

Further, as the anthracene-based compound used for the electron transport layer 6 (when the second electron transport layer 6a is provided, particularly the second electron transport layer 6a), the above-mentioned formula IRH2 mentioned as the host material contained in the light emitting layer 5 described above is used. It may be a compound represented by the above formula, but is preferably a compound represented by the above formula IRH2-A, the above formula IRH2-B, the above formula IRH2-C or the above formula IRH2-D, and more specifically, For example, it is preferably a compound represented by the above formula IRH2-1 to 56.

Further, the HOMO of the constituent material of the electron transport layer 6 (more specifically, the second electron transport layer 6a) preferably has a difference of 0.2 eV or more from the HOMO of the host material used for the light emitting layer 5. As a result, it is possible to reduce holes from escaping from the light emitting layer 5 to the electron transport layer 6 and improve the luminous efficiency.

Further, the HOMO of the constituent material of the second electron transport layer 6a is preferably 5.5 eV or more and 6.0 eV or less, and the LUMO of the constituent material of the second electron transport layer 6a is 2.5 eV or more and 3. It is preferably 0 eV or less.

Further, the HOMO of the constituent material of the first electron transport layer 6b is preferably 5.8 eV or more and 6.5 eV or less, and the LUMO of the constituent material of the first electron transport layer 6b is 2.8 eV or more and 3. It is preferably 5 eV or less.

Further, the thickness of the second electron transport layer 6a is preferably thicker than the thickness of the first electron transport layer 6b. As a result, while suppressing the drive voltage of the light emitting element 1, electrons can be efficiently transported and injected into the light emitting layer 5, and deterioration of the electron transport layer 6 can be reduced.

The specific thickness of the second electron transport layer 6a is preferably 30 nm or more and 150 nm or less, and more preferably 70 nm or more and 90 nm or less. As a result, while suppressing the drive voltage of the light emitting element 1, electrons can be efficiently transported and injected into the light emitting layer 5, and deterioration of the electron transport layer 6 can be reduced.

Further, the thickness of the entire electron transport layer 6 is preferably 55 nm or more and 200 nm or less, and more preferably 70 nm or more and 95 nm or less. As a result, electrons can be efficiently transported and injected into the light emitting layer 5 while suppressing the driving voltage of the light emitting element 1.

The second electron transport layer 6a may be omitted depending on the combination of the constituent materials of the first electron transport layer 6b and the light emitting layer 5.

(Electron injection layer)
The electron injection layer 7 has a function of improving the electron injection efficiency from the cathode 8.

Examples of the constituent material (electron-injectable material) of the electron-injecting layer 7 include various inorganic insulating materials and various inorganic semiconductor materials.

Examples of such an inorganic insulating material include alkali metal chalcogenides (oxides, sulfides, selenes, tellurides), alkaline earth metal chalcogenides, alkali metal halides and alkaline earth metal halides. And one or more of these can be used in combination. By forming the electron injection layer 7 using these as the main materials, the electron injection property can be further improved. In particular, alkali metal compounds (alkali metal chalcogenides, alkali metal halides, etc.) have a very small work function, and by forming the electron injection layer 7 using these, the light emitting element 1 can obtain high brightness. Become.

Examples of the alkali metal chalcogenide include Li ₂ O, LiO, Na ₂ S, Na ₂ Se, Na O and the like.

Examples of the alkaline earth metal chalcogenide include CaO, BaO, SrO, BeO, BaS, MgO, CaSe and the like.

Examples of the alkali metal halide include CsF, LiF, NaF, KF, LiCl, KCl, NaCl and the like.

Examples of the halide of the alkaline earth metal include CaF ₂ , BaF ₂ , SrF ₂ , MgF ₂ , BeF _{2 and the} like.

Further, as the inorganic semiconductor material, for example, an oxide containing at least one element of Li, Na, Ba, Ca, Sr, Yb, Al, Ga, In, Cd, Mg, Si, Ta, Sb and Zn. , Nitride, oxide nitride and the like, and one or more of these can be used in combination.

The average thickness of the electron injection layer 7 is not particularly limited, but is preferably 0.1 nm or more and 1000 nm or less, more preferably 0.2 nm or more and 100 nm or less, and 0.2 nm or more and 50 nm or less. It is more preferable to have it.

The electron injection layer 7 may be omitted depending on the constituent materials and thickness of the cathode 8 and the electron transport layer 6.

(Sealing member)
The sealing member 9 is provided so as to cover the anode 3, the laminate 14, and the cathode 8, and has a function of airtightly sealing them and blocking oxygen and water. By providing the sealing member 9, effects such as improvement of 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 9 include Al, Au, Cr, Nb, Ta, Ti, alloys containing these, silicon oxide, and various resin materials. When a conductive material is used as the constituent material of the sealing member 9, it is necessary between the sealing member 9 and the anode 3, the laminate 14, and the cathode 8 in order to prevent a short circuit. Therefore, it is preferable to provide an insulating film.

Further, the sealing member 9 may be formed into a flat plate shape so as to face the substrate 2 and the space between them may be sealed with a sealing material such as a thermosetting resin.

According to the light emitting device 1 configured as described above, the benzo-bis-thiadiazole-based compound is used as the light emitting material of the light emitting layer 5, and the tetracene-based material is used as the host material of the light emitting layer 5, so that the near infrared region is used. In addition to being able to emit light in the light, it is possible to improve efficiency and extend the service life.

The light emitting device of the present invention is not limited to the configuration of the light emitting element 1 described above, and has an anode 3, a light emitting layer 5, and a cathode 13, and the light emitting layer 5 has a benzo-represented by the general formula IRD as a light emitting material. Any structure may be used as long as it contains a bi-thiazol-based compound. For example, layers other than the anode 3, the light emitting layer 5 and the cathode 13 may be omitted, or any other layer may be omitted. Any number of layers may be added. Specifically, as the light emitting element to which an arbitrary layer is added, for example, even if it has a light emitting layer that emits light in the visible light region or the ultraviolet region in addition to the light emitting layer 5 that emits light in the near infrared region. Good. Further, in this case, the light emitting layer 5 that emits light in the near infrared region and the light emitting layer that emits light in the visible light region or the ultraviolet region may be laminated, or the regions are separated and arranged in parallel. It may be a thing, and further, it may be a combination of these.
The light emitting element 1 as described above can be manufactured, for example, as follows.

[1] First, a substrate 2 is prepared, and an 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 vapor deposition, a wet plating method such as electrolytic plating, a thermal spraying method, a sol-gel method, a MOD method, or a metal leaf. It can be formed by joining the above.

[2] Next, the hole injection layer 4 is formed on the anode 3.
The hole injection layer 4 is preferably formed by a vapor phase process using, for example, a CVD method, a dry plating method such as vacuum deposition or sputtering.

In the hole injection layer 4, for example, a material for forming a hole injection layer formed by dissolving a hole injectable material in a solvent or dispersing it in a dispersion medium is supplied onto the anode 3, and then dried (solvent-free or It can also be formed by (dedispersion medium).

As a method for supplying the material for forming the hole injection layer, for example, various coating methods such as a spin coating method, a roll coating method, and an inkjet 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 preparing the material for forming the hole injection layer include various inorganic solvents, various organic solvents, and mixed solvents containing these.

The drying can be performed by, for example, leaving in an atmospheric pressure or reduced pressure atmosphere, heat treatment, spraying of an inert gas, or the like.

Further, prior to this step, the upper surface of the anode 3 may be subjected to oxygen plasma treatment. Thereby, it is possible to impart liquidity 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 conditions for oxygen plasma treatment include, for example, a plasma power of 100 W or more and 800 W or less, an oxygen gas flow rate of 50 mL / min or more and 100 mL / min or less, and a transport speed of the member to be processed (anode 3) of 0.5 mm / sec or more. It is preferably about 10 mm / sec or less.

[3] Next, the light emitting layer 5 is formed on the hole injection layer 4.
The light emitting layer 5 can be formed by a vapor phase process using, for example, a dry plating method such as vacuum deposition.

[4] Next, an electron transport layer 6 (first electron transport layer 6b and second electron transport layer 6a) is formed on the light emitting layer 5.

The electron transport layer 6 (first electron transport layer 6b and second electron transport layer 6a) is preferably formed by a vapor phase process using, for example, a dry plating method such as vacuum deposition.

In the electron transport layer 6, for example, a material for forming an electron transport layer obtained by dissolving an electron transport material in a solvent or dispersing it in a dispersion medium is supplied onto the light emitting layer 5, and then dried (desolvent or dedispersed). It can also be formed by mediating.

[5] Next, the electron injection layer 7 is formed on the electron transport layer 6.
When an inorganic material is used as the constituent material of the electron injection layer 7, the electron injection layer 7 is subjected to, for example, a vapor phase process using a CVD method, a dry plating method such as vacuum deposition or sputtering, coating and firing of inorganic fine particle ink. Etc. can be formed.

[6] Next, the cathode 8 is formed on the electron injection layer 7.
The cathode 8 can be formed by, for example, a vacuum vapor deposition method, a sputtering method, joining of metal foils, coating and firing of metal fine particle ink, and the like.

The light emitting element 1 is obtained through the above steps.
Finally, the sealing member 9 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 vertical sectional view showing an embodiment of a display device to which the light emitting device of the present invention is applied.

The 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 each light emitting element 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 flattening layer 22 made of an insulating material is formed so as to cover these driving transistors 24.

Each drive 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. It has 245 and.

A light emitting element 1A is provided on the flattening layer corresponding to each driving transistor 24.

In the light emitting element 1A, a reflective film 32, a corrosion prevention film 33, an anode 3, a laminate (organic EL light emitting portion) 14, a cathode 13, and a cathode cover 34 are laminated in this order on the flattening layer 22. In the present embodiment, the anode 3 of each light emitting element 1A constitutes a pixel electrode, and is electrically connected to the drain electrode 245 of each driving transistor 24 by a conductive portion (wiring) 27. Further, the cathode 13 of each light emitting element 1A is a common electrode.

The light emitting element 1A in FIG. 2 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 applications, for example.

According to such a display device 100, it is possible to emit light in the near infrared region. Further, since the light emitting element 1 having high efficiency and long life capable of emitting light in a near infrared region in a wide wavelength region is provided, it is excellent in reliability.

(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.
The authentication device 1000 shown in FIG. 3 is a biometric authentication device that authenticates an individual using the biometric information of the living body F (fingertip in the present embodiment).

The authentication device 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 100B includes a plurality of the above-mentioned light emitting elements 1, and irradiates the living body F, which is the object to be imaged, with light in the near infrared region. For example, the plurality of light emitting elements 1 of the light source 100B are arranged along the outer peripheral portion of the cover glass 1001.
The cover glass 1001 is a portion where the living body F comes into contact with or is in close proximity to the living body F.

The microlens array 1002 is provided on the side opposite to the side where the living body F of the cover glass 1001 comes into contact with or is close to the living body F. The microlens array 1002 is configured by arranging a plurality of microlenses 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 is composed of 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, CCD (Charge Coupled Device), CMOS or the like can be used.

The light emitting element drive unit 1006 is a drive circuit that drives the light source 100B.
The light receiving element drive 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 the drive of the light emitting element driving unit 1006 and the light receiving element driving unit 1004.

Further, the control unit 1005 has a function of authenticating the living body F by comparing the light receiving result of the light receiving element group 1003 with the biometric authentication information stored in advance.

For example, the control unit 1005 generates an image pattern (for example, a vein pattern) relating to the living body F based on the light receiving result of the light receiving element group 1003. Then, the control unit 1005 compares the image pattern with the image pattern stored in advance as biometric authentication information, and authenticates the living body F (for example, vein authentication) based on the comparison result.

According to such an authentication device 1000, biometric authentication can be performed using near infrared light. Further, since the light emitting element 1 having high efficiency and long life capable of emitting light in a near infrared region in a wide wavelength region is provided, it is excellent in reliability.
Such an authentication device 1000 can be incorporated into various electronic devices.

(Electronics)
FIG. 4 is a perspective view showing the configuration of a mobile (or notebook) personal computer to which the electronic device of the present invention is applied.

In this figure, the personal computer 1100 is composed of a main body 1104 including a keyboard 1102 and a display unit 1106 including a display, and the display unit 1106 can rotate with respect to the main body 1104 via a hinge structure. Is supported by.

In the personal computer 1100, the authentication device 1000 described above is provided in the main body 1104.

Such a personal computer 1100 is excellent in reliability because it includes a highly efficient and long-life light emitting element 1 capable of emitting light in a near infrared region in a wide wavelength region.

In addition to the personal computer (mobile personal computer) shown in FIG. 4, the electronic device of the present invention includes, for example, a smartphone, a tablet terminal, a clock, a mobile phone, a digital still camera, a television, a video camera, and a viewfinder type. , Monitor direct-view video tape recorder, laptop personal computer, car navigation device, pager, electronic notebook (including communication function), electronic dictionary, calculator, electronic game equipment, word processor, workstation, videophone, security TV monitors, electronic binoculars, POS terminals, devices equipped with touch panels (eg cash dispensers of financial institutions, automatic ticket vending machines), medical devices (eg electronic thermometers, blood pressure monitors, blood glucose meters, pulse measuring devices, pulse wave measuring devices, hearts) Electronic display device, ultrasonic diagnostic device, display device for endoscope), fish finder, various measuring devices, instruments (for example, instruments for vehicles, aircraft, ships), flight simulators, other various monitors, projectors, etc. It can be applied to the projection type display device and the like.

Further, the electronic device of the present invention has a configuration provided with the above-mentioned light source 100B, for example, a blood oxygen concentration measuring device, a blood glucose level measuring device, a skin diagnostic device, a body fat measuring device, an in-vivo fluorescent substance observer, and a skin. Medical devices (biological sensors) such as cancer diagnostic devices, pupil observation devices, and blood vessel observation devices, infrared scanner devices, and the like can be mentioned as other than the configuration provided with the authentication device 1000.

Although the compound of the present invention, the compound for a light emitting element, the light emitting element, the light emitting device, the light source, the authentication device and the electronic device have been described above based on the illustrated embodiments, the present invention is not limited thereto.
Further, 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.
1-1. Production of Luminescent Material A benzo-bis-thiadiazole-based compound represented by the above formula IRD-A2 was synthesized by the following steps 1 to 5.

[Step 1]

First, 500 g of fuming nitric acid (1.50) was charged into 2 liter corben and cooled to an internal temperature of 3 ° C. Concentrated sulfuric acid (345 ml) was slowly added dropwise thereto at an internal temperature of 10 ° C. or lower. Then, the raw material 4,7-bromo-2,1,3-benzobisthiadiazole (75.0 g, 255 mmol) was slowly added in portions at an internal temperature of 10 ° C. or lower, left at room temperature, and stirred overnight.

Then, the reaction solution was poured into ice water (2.7 L), and the solid was collected by filtration. Toluene (80 mL) was added to the obtained solid for recrystallization. The obtained solid was recrystallized again with toluene (40 mL) to obtain the desired product (yield 26.8 g, yield 31%).

[Step 2]

First, 9- (4-bromophenyl) carbazole (116 g, 360 mmol) and 4-bromodiphenylamine (89.3 g, 360 mmol) were added to xylene (1.7 liters) in 3 liters of corben. The temperature is raised to 105 ° C., tBu ₃ P · HBF ₄ (4.18 g, 14.4 mmol) and Pd ₂ (dba ₃ ) (6.59 g, 7.20 mmol) are added, and then tBuONa (41.6 g) is added. 433 mmol) was added in portions. Then, the temperature was raised to 115 ° C., and the mixture was stirred for 1 hour.

Then, after cooling to room temperature, the reaction solution was added to water (1.8 liters), and the organic layer was separated. The organic layer was washed with water (500 ml), separated, and concentrated under reduced pressure. The obtained crude product (140 g) was purified by silica gel column chromatography (2 kg, development: toluene / heptane = 1/2) to obtain the desired product (yield 61.6 g, yield 35%).

[Step 3]

A bromo compound (product of step 2) (59.2 g, 121 mmol) was dissolved in dehydrated THF (430 mL) in 1 liter corben under an argon gas stream and cooled to −70 ° C. 1.64M n-BuLi in Hexane (80 mL, 131 mmol) was added dropwise thereto at an internal temperature of −65 ° C. or lower, and the mixture was stirred as it was for 30 minutes. Then, tributyltin chloride (39.3 g, 121 mmol) was added dropwise at an internal temperature of −65 ° C. or lower, the temperature was raised to room temperature, and the mixture was stirred overnight.

Then, NaF (8.7 g, 207 mmol) was dissolved in water (660 mL), and the reaction solution was poured into the solution. Toluene (345 mL) was added, and the mixture was stirred for 1 hour, then the organic layer was separated, and the organic layer was washed with water (800 mL × 2). Then, the target product was obtained by performing a concentration operation under reduced pressure (yield 80.4 g, yield 95%).

[Step 4]

First, under Ar gas, dioxane (product of step 1) (7.3 g, 19.0 mmol) and tin (product of step 3) (14.0 g, 20 mmol) were placed in a 500 ml three-necked flask. It was dissolved in (350 ml), Pd (PPh ₃ ) ₄ (1.13 g, 0.975 mmol) was added thereto, the temperature was raised to an internal temperature of 95 ° C., and the mixture was stirred overnight.

Then, after cooling to room temperature, the reaction solution was concentrated under reduced pressure. The obtained solid was washed with toluene, and then recrystallized from 400 ml of toluene to obtain the desired product (yield 4.3 g, yield 32%).

[Step 5]

2-Bromonaphthalene (45.9 g, 110 mmol) was dissolved in dehydrated THF (430 mL) in 1 liter corben under an argon gas stream and cooled to −70 ° C. 1.64M n-BuLi in Hexane (80 mL, 131 mmol) was added dropwise thereto at an internal temperature of −65 ° C. or lower, and the mixture was stirred as it was for 30 minutes. Then, tributyltin chloride (35.7 g, 110 mmol) was added dropwise at an internal temperature of −65 ° C. or lower, the temperature was raised to room temperature, and the mixture was stirred overnight.

Then, NaF (8.7 g, 207 mmol) was dissolved in water (660 mL), and the reaction solution was poured into the solution. Toluene (345 mL) was added, and the mixture was stirred for 1 hour, then the organic layer was separated, and the organic layer was washed with water (800 mL × 2). Then, the target product was obtained by performing a concentration operation under reduced pressure (yield 42.2 g, yield 92%).

[Step 6]

First, dioxane a bromo compound (product of step 4) (14.3 g, 20.1 mmol) and a tin compound (product of step 3) (20.0 g, 48 mmol) in a 500 ml three-necked flask under Ar gas. It was dissolved in (350 ml), Pd (PPh3) 4 (1.13 g, 0.975 mmol) was added thereto, the temperature was raised to an internal temperature of 95 ° C., and the mixture was stirred overnight.

Then, after cooling to room temperature, the reaction solution was concentrated under reduced pressure. The obtained solid was washed with toluene, and then recrystallized from 400 ml of toluene to obtain the desired product (yield 5.0 g, yield 33%).

[Step 7]

First, acetic acid (200 ml) and Fe (10.2 g, 182 mmol) were added to a 300 ml three-necked flask under Ar gas, and the temperature was raised to an internal temperature of 65 ° C. The nitro compound (4.7 g, 6.2 mmol) obtained in step 6 was slowly added thereto in divided portions, the temperature was raised to 80 ° C., and the mixture was stirred as it was for 3 hours.

Then, the reaction solution was cooled to room temperature and then poured into water (300 ml). Then, the solid (including Fe) was filtered. Organic matter was extracted from the solid using THF (300 ml) and concentrated under reduced pressure. Toluene (150 ml) was added to the obtained residue, and the mixture was concentrated again under reduced pressure to obtain the desired product (yield 3.0, 70% yield).

[Step 8]

Under Ar gas, the amine compound (2.0 g, 2.8 mmol) obtained in step 7 was dissolved in dehydrated pyridine (90 ml) in a 300 ml three-necked flask, and N-thionylaniline (0.84 g, 6 mmol) was added. Trimethylsilyl chloride (3.6 g, 33 mmol) was added. Then, the temperature was raised to an internal temperature of 80 ° C., and the mixture was stirred overnight.

The reaction solution was cooled to room temperature and then poured into water (200 ml). The precipitated crystals were filtered out, and the solid was washed with THF to obtain 1.0 g of a solid (crystal).

Purification was performed by silica gel chromatography (silica gel 100 g, developing solvent chlorobenzene).

Finally, purification was carried out by a reprecipitation method using xylene to obtain a target compound represented by the chemical formula IRD-A2 (yield 0.6 g, yield 30%).

1-2. Production of Host Material The tetracene-based host material represented by the formula IRH1-5 and the like and the anthracene-based host material represented by the formula IRH2-30 and the like are described in JP2013-177327 and JP2013-179123, respectively. Was synthesized with reference to the production method of.

2. 2. Manufacture of light emitting element (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 this substrate by a sputtering method.

Then, the substrate was immersed in acetone and 2-propanol in this order, ultrasonically cleaned, and then subjected to oxygen plasma treatment and argon plasma treatment. These plasma treatments were carried out at a plasma power of 100 W, a gas flow rate of 20 sccm, and a treatment time of 5 sec, respectively.

<2> Next, the compound represented by the formula HIL-1 was vapor-deposited on the ITO electrode by a vacuum vapor deposition method to form a hole injection layer (HIL) having an average thickness of 70 nm.

<3> Next, the constituent material of the light emitting layer was vapor-deposited on the hole injection layer by a vacuum vapor deposition method to form a light emitting layer having an average thickness of 25 nm. As the constituent material of the light emitting layer, a compound represented by the formula IRD-A2 (benzo-bis-thiadiazole-based compound) is used as a light emitting material (guest material), and a compound represented by the formula IRH1-5 (tetracene) is used as a host material. System material) was used. Further, the content (doping concentration) of the light emitting material (dopant) in the light emitting layer was set to 2.0 wt%.

<4> Next, the compound represented by ETL1-3 (azaindolizine compound) is formed on the light emitting layer by a vacuum vapor deposition method, and an electron transport layer having an average thickness of 95 nm (first electron transport layer) is formed. ETL1) was formed.

<5> Next, lithium fluoride (LiF) was formed on the electron transport layer by a vacuum vapor deposition method to form an electron injection layer having an average thickness of 1 nm.

<6> Next, Al was formed on the electron injection layer by a vacuum vapor deposition method. As a result, a cathode having an average thickness of 100 nm composed of Al was formed.

<7> Next, a protective cover (sealing member) made of glass was covered so as to cover each of the formed layers, and the mixture was fixed and sealed with an epoxy resin.
A light emitting element was manufactured by the above steps.

(Example 2)
The average thickness of the hole injection layer formed in the step <2> is 90 nm, a compound represented by the formula IRD-A13 is used as the light emitting material (dopant) used in the step <3>, and further, the step <3>. A light emitting device was manufactured in the same manner as in Example 1 described above, except that the average thickness of the electron transport layer formed in 4> was 105 nm.

(Example 3)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-A15 was used as the light emitting material (dopant) used in the step <3>.

(Example 4)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-A22 was used as the light emitting material (dopant) used in the step <3>.

(Example 5)
A light emitting device was manufactured in the same manner as in Example 1 described above, except that the compound represented by the formula IRD-A221 was used as the light emitting material (dopant) used in the step <3>.

(Example 6)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-A232 was used as the light emitting material (dopant) used in the step <3>.

(Example 7)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-A235 was used as the light emitting material (dopant) used in the step <3>.

(Example 8)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-A242 was used as the light emitting material (dopant) used in the step <3>.

(Example 9)
A light emitting device was manufactured in the same manner as in Example 1 described above, except that the compound represented by the formula IRD-B2 was used as the light emitting material (dopant) used in the step <3>.

(Example 10)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-B13 was used as the light emitting material (dopant) used in the step <3>.

(Example 11)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-B15 was used as the light emitting material (dopant) used in the step <3>.

(Example 12)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-B22 was used as the light emitting material (dopant) used in the step <3>.

(Example 13)
A light emitting device was manufactured in the same manner as in Example 1 described above, except that the compound represented by the formula IRD-B166 was used as the light emitting material (dopant) used in the step <3>.

(Example 14)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-B177 was used as the light emitting material (dopant) used in the step <3>.

(Example 15)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-B180 was used as the light emitting material (dopant) used in the step <3>.

(Example 16)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-B187 was used as the light emitting material (dopant) used in the step <3>.

(Example 17)
A light emitting device was manufactured in the same manner as in Example 1 described above, except that the compound represented by the formula IRD-B188 was used as the light emitting material (dopant) used in the step <3>.

(Example 18)
A light emitting device was manufactured in the same manner as in Example 1 described above, except that the compound represented by the formula IRD-B199 was used as the light emitting material (dopant) used in the step <3>.

(Example 19)
A light emitting device was manufactured in the same manner as in Example 1 described above, except that the compound represented by the formula IRD-C2 was used as the light emitting material (dopant) used in the step <3>.

(Example 20)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-C13 was used as the light emitting material (dopant) used in the step <3>.

(Example 21)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-C15 was used as the light emitting material (dopant) used in the step <3>.

(Example 22)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-C22 was used as the light emitting material (dopant) used in the step <3>.

(Example 23)
A light emitting device was manufactured in the same manner as in Example 1 described above, except that the compound represented by the formula IRD-C112 was used as the light emitting material (dopant) used in the step <3>.

(Example 24)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-C123 was used as the light emitting material (dopant) used in the step <3>.

(Example 25)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-C125 was used as the light emitting material (dopant) used in the step <3>.

(Example 26)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-C132 was used as the light emitting material (dopant) used in the step <3>.

(Example 27)
A light emitting device was manufactured in the same manner as in Example 1 described above, except that the compound represented by the formula IRD-C166 was used as the light emitting material (dopant) used in the step <3>.

(Example 28)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-C177 was used as the light emitting material (dopant) used in the step <3>.

(Example 29)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-C180 was used as the light emitting material (dopant) used in the step <3>.

(Example 30)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the formula IRD-C187 was used as the light emitting material (dopant) used in the step <3>.

(Example 31)
In the step <3>, a light emitting device was manufactured in the same manner as in Example 13 described above, except that the content (doping concentration) of the light emitting material (dopant) in the light emitting layer was set to 0.5 wt%.

(Example 32)
In the step <3>, a light emitting device was manufactured in the same manner as in Example 13 described above, except that the content (doping concentration) of the light emitting material (dopant) in the light emitting layer was set to 5.0 wt%.

(Example 33)
A light emitting device was manufactured in the same manner as in Example 13 described above, except that the compound represented by the formula IRH1-2 (tetracene-based material) was used as the host material used in the step <3>.

(Example 34)
A light emitting device was manufactured in the same manner as in Example 13 described above, except that the compound represented by the formula IRH1-13 (tetracene-based material) was used as the host material used in the step <3>.

(Example 35)
A light emitting device was manufactured in the same manner as in Example 13 described above, except that the compound represented by the formula IRH2-30 (anthracene-based material) was used as the host material used in the step <3>.

(Example 36)
A light emitting device was manufactured in the same manner as in Example 13 described above, except that the compound represented by the formula IRH2-47 (anthracene-based material) was used as the host material used in the step <3>.

(Example 37)
A light emitting device was manufactured in the same manner as in Example 13 described above, except that the compound represented by the formula IRH2-52 (anthracene-based material) was used as the host material used in the step <3>.

(Example 38)
A light emitting device was manufactured in the same manner as in Example 13 described above, except that Alq ₃ was used as the host material used in the step <3>.

(Example 39)
The light emitting device is formed in the same manner as in Example 13 described above, except that the average thickness of the light emitting layer formed in the step <3> is 10 nm and the thickness of the electron transport layer formed in the step <4> is 110 nm. Manufactured.

(Example 40)
The light emitting device is formed in the same manner as in Example 13 described above, except that the average thickness of the light emitting layer formed in the step <3> is 50 nm and the thickness of the electron transport layer formed in the step <4> is 70 nm. Manufactured.

(Example 41)
In the step <4>, light is emitted in the same manner as in Example 13 described above, except that a second electron transport layer (ETL2) is further provided between the light emitting layer and the electron transport layer (first electron transport layer). Manufactured the element.

The second electron transport layer was formed by forming a film of the compound represented by IRH2-30 (anthracene compound) on the first electron transport layer by a vacuum vapor deposition method. The thickness of the first electron transport layer was 15 nm, and the thickness of the second electron transport layer was 80 nm.

(Example 42)
A light emitting device was manufactured in the same manner as in Example 41 described above, except that the thickness of the first electron transport layer was 5 nm and the thickness of the second electron transport layer was 90 nm.

(Comparative Example 1)
A light emitting device is manufactured in the same manner as in Example 2 described above, except that the compound represented by the following formula NIR-C1 is used as the light emitting material (dopant) used in the step <3> and Alq ₃ is used as the host material. did.

(Comparative Example 2)
A light emitting device was manufactured in the same manner as in Example 1 described above, except that the compound represented by the following formula NIR-C1 was used as the light emitting material (dopant) used in the step <3>.

(Comparative Example 3)
A light emitting device was manufactured in the same manner as in Example 2 described above, except that the compound represented by the following formula NIR-C2 was used as the light emitting material (dopant) used in the step <3>.

3. 3. Evaluation For each example and each comparative example, a constant current power source (KEYTHLEY2400 manufactured by Toyo Technica Co., Ltd.) was used to pass a constant current of 100 mA / cm ² through the light emitting element, and the emission peak wavelength at that time was measured by a high-speed spectroradiometer (KEITHLEY2400). The measurement was performed using Soma Optical S-9000). In addition, the external quantum efficiency (luminous efficiency) EQE (%) in the wavelength range of 860 nm to 1030 nm was also measured using a thin photodiode power sensor (S132C manufactured by Thorlabs).

Further, a constant current of 100 mA / cm ² was passed through the light emitting element, and the time (LT50) at which the brightness became 50% of the initial brightness was also measured.
The results of these measurements are shown in Table 1.

As is clear from Table 1, the light emitting element of each example emits light in the near infrared region having a wide wavelength region of 870 nm or more and 1020 nm or less, and emits light except for Example 38 as compared with the light emitting element of the comparative example. Excellent balance between efficiency and longevity.

Further, comparing the light emitting elements of Examples 33 to 37 with the light emitting elements of Example 38, the light emitting elements of Examples 33 to 37 have higher external quantum efficiency (luminous efficiency) than the light emitting elements of Example 38. It is high and can reduce the density quenching property.

1 ... light emitting element, 1A ... light emitting element, 2 ... substrate, 3 ... electrode, 4 ... hole injection layer, 5 ... light emitting layer, 6 ... electron transport layer, 6a ... second electron transport layer, 6b ... first electron transport Layers, 7 ... electron injection layer, 8 ... cathode, 9 ... sealing member, 13 ... cathode, 14 ... laminate, 20 ... sealing substrate, 21 ... substrate, 22 ... flattening layer, 24 ... driving transistor, 27 ... Conductive part, 31 ... partition wall, 32 ... reflective film, 33 ... corrosion prevention film, 34 ... cathode cover, 35 ... epoxy layer, 100 ... display device, 100B ... light source, 241 ... semiconductor layer, 242 ... gate insulating layer, 243 ... Gate electrode, 244 ... Source electrode, 245 ... Drain electrode, 1000 ... Authentication device, 1001 ... Cover glass, 1002 ... Microlens array, 1003 ... Light receiving element group, 1004 ... Light receiving element drive unit, 1005 ... Control unit, 1006 ... Light emitting element drive unit, 1100 ... personal computer, 1102 ... keyboard, 1104 ... main body unit, 1106 ... display unit, F ... living body

Claims (13)

A compound characterized by being represented by the following general formula IRD.

[In the general formula IRD, the group X is a substituent having 1 to 20 carbon atoms including an aromatic ring, and the group Y is a substituent having 1 to 20 carbon atoms including an aromatic ring, and each group Z ₁ and Z ₂ are both carbazole groups, or one is either a carbazole group and the other is a diphenylamine group, and each group R ₁ and R ₂ are both hydrogen atoms or one hydrogen atom. And the other is either a carbazole group or a diphenylamine group. ] A compound for a light emitting device, which is represented by the following general formula IRD.

[In the general formula IRD, the group X is a substituent having 1 to 20 carbon atoms including an aromatic ring, and the group Y is a substituent having 1 to 20 carbon atoms including an aromatic ring, and each group Z ₁ and Z ₂ are both carbazole groups, or one is either a carbazole group and the other is a diphenylamine group, and each group R ₁ and R ₂ are both hydrogen atoms or one hydrogen atom. And the other is either a carbazole group or a diphenylamine group. ] With the anode
With the cathode
It has a light emitting layer provided between the anode and the cathode and emitting light when energized between the anode and the cathode.
A light emitting device characterized in that the light emitting layer is composed of a compound represented by the following general formula IRD as a light emitting material.

[In the general formula IRD, the group X is a substituent having 1 to 20 carbon atoms including an aromatic ring, and the group Y is a substituent having 1 to 20 carbon atoms including an aromatic ring, and each group Z ₁ and Z ₂ are both carbazole groups, or one is either a carbazole group and the other is a diphenylamine group, and each group R ₁ and R ₂ are both hydrogen atoms or one hydrogen atom. And the other is either a carbazole group or a diphenylamine group. ] The light emitting device according to claim 3, further comprising a compound represented by the following formula IRH1 as a host material for holding the light emitting material.

[In the above formula IRH1, n represents a natural number of 1 to 12, and R represents an aryl group and an arylamino group which may independently have a hydrogen atom, an alkyl group and a substituent, respectively. ] The light emitting device according to claim 3, further comprising a compound represented by the following formula IRH2 as a host material for holding the light emitting material.

[In the above formula IRH2, n represents a natural number of 1 to 10, and R represents an aryl group and an arylamino group which may independently have a hydrogen atom, an alkyl group and a substituent, respectively. ] The light emitting device according to claim 4 or 5, wherein the host material is composed of a carbon atom and a hydrogen atom. The light emitting device according to any one of claims 3 to 6, wherein the content of the light emitting material in the light emitting layer is 0.5 wt% or more and 5.0 wt% or less. The light emitting device according to any one of claims 3 to 7, further comprising an electron transport layer provided between the light emitting layer and the cathode and comprising a compound having an anthracene skeleton. The light emitting device according to any one of claims 3 to 8, wherein the thickness of the light emitting layer is 10 nm or more and 50 nm or less. A light emitting device including the light emitting element according to any one of claims 3 to 9. A light source comprising the light emitting element according to any one of claims 3 to 9. An authentication device comprising the light emitting element according to any one of claims 3 to 9. An electronic device comprising the light emitting element according to any one of claims 3 to 9.

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