JP6573442B2 - Organic electroluminescence device and electronic device - Google Patents

Description

  The present invention relates to an organic electroluminescence element and an electronic apparatus.

When a voltage is applied to an organic electroluminescence element (hereinafter sometimes referred to as an organic EL element), holes from the anode and electrons from the cathode are injected into the light emitting layer. Then, in the light emitting layer, the injected holes and electrons are recombined to form excitons. At this time, singlet excitons and triplet excitons are generated at a ratio of 25%: 75% according to the statistical rule of electron spin. When classified according to the light emission principle, the fluorescence type uses light emitted from singlet excitons, and therefore the internal quantum efficiency of the organic EL element is said to be limited to 25%. On the other hand, in the phosphorescent type, since light emission by triplet excitons is used, it is known that the internal quantum efficiency can be increased to 100% when intersystem crossing is efficiently performed from singlet excitons.
In recent years, fluorescent organic EL devices have been developed for long-life technology and are being applied to full-color displays such as mobile phones and televisions.

Against this background, highly efficient fluorescent organic EL elements using delayed fluorescence have been proposed and developed. For example, an organic EL element using a TTF (triplet-triplet fusion) mechanism, which is one of delayed fluorescence mechanisms, has been proposed. The TTF mechanism uses a phenomenon in which singlet excitons are generated by collision of two triplet excitons.
If delayed fluorescence due to this TTF mechanism is used, it is considered that the internal quantum efficiency can be theoretically increased to 40% even in fluorescence type light emission. However, it still has a problem of higher efficiency than phosphorescent light emission. Therefore, in order to further improve the internal quantum efficiency, a method using another delayed fluorescence mechanism has been studied.

For example, a TADF (Thermally Activated Delayed Fluorescence, heat activated delayed fluorescence) mechanism can be mentioned. This TADF mechanism uses the phenomenon that reverse intersystem crossing from triplet excitons to singlet excitons occurs when a material with a small energy difference (ΔST) between singlet levels and triplet levels is used. To do. For example, Non-Patent Document 1 discloses an organic EL element using the TADF mechanism.
Non-Patent Document 1 describes (4s, 6s) -2,4,5,6-tetra (9H-carbazol-9-yl) isophthalonitrile (4CzIPN) as a TADF light emitting material. Non-Patent Document 1 discloses a light emitting layer containing 4CzIPN and mCBP, and a 9,9 ′, 9 ″ -triphenyl-9H, 9′H, 9 ″ H-3 adjacent to the anode side of the light emitting layer. , 3 ′: 6 ′, 3 ″ -tercarbazole (TrisPCz), and an organic EL device including a hole transport layer. In the organic EL device described in Non-Patent Document 1, triplet excitons are described. TrisPCz having a large triplet energy is used for the hole transport layer adjacent to the anode side of the light emitting layer.In Non-Patent Document 1, the doping concentration of the light emitting layer, that is, 4CzIPN By changing the concentration from 3% by weight to 15% by weight, an attempt is made to extend the life of the organic EL element.

Hajime Nakanotani et al., Scientific Reports 3, doi: 10.1038 / srep02127, July 3, 2013

  However, the organic EL element is required to reduce the driving voltage.

  The objective of this invention is providing the organic electroluminescent element which can reduce a drive voltage, suppressing the fall of luminous efficiency. Another object of the present invention is to provide an electronic apparatus provided with the organic electroluminescence element.

The organic electroluminescence device according to one embodiment of the present invention is
The anode,
A cathode,
A first organic layer provided between the anode and the cathode;
A second organic layer provided between the cathode and the first organic layer and adjacent to the first organic layer,
The first organic layer contains a first material,
The second organic layer contains the second material at a concentration of 12% by mass or more,
The second material is a thermally activated delayed fluorescent material;
The ionization potential IP _B of the first material and the ionization potential IP _T of the thermally activated delayed fluorescent material satisfy the relationship of the following formula (Equation 1).

IP _B > IP _T (1)

In addition, the organic electroluminescence element according to one embodiment of the present invention is
The anode,
A cathode,
A first organic layer provided between the anode and the cathode;
A second organic layer provided between the cathode and the first organic layer and adjacent to the first organic layer,
The first organic layer contains a first material,
The second organic layer contains a light emitting material having a partial structure represented by the following general formula (1) and a partial structure represented by the following general formula (2) in one molecule,
The emission maximum peak wavelength of the light emitting material is 510 nm or more,
The ionization potential IP _B of the first material and the ionization potential IP _E of the light emitting material satisfy the relationship of the following mathematical formula (Formula 2).

IP _B > IP _E (Expression 2)

(In the general formula (1), CN is a cyano group, and n is an integer of 1 or more.
Z _{1 to} Z ₆ are each independently a nitrogen atom, a carbon atom bonded to CN, or a carbon atom bonded to another atom in the molecule of the light emitting material.
The 6-membered ring structure represented by the general formula (1) may construct a ring structure at an arbitrary position. )

(In the general formula (2), F and G each independently represent a ring structure.
m is 0 or 1.
When m is 1, Y ₁ represents a single bond, an oxygen atom, a sulfur atom, a selenium atom, a carbon atom, a silicon atom, or a germanium atom. )

  ADVANTAGE OF THE INVENTION According to this invention, the organic electroluminescent element which can reduce a drive voltage can be provided, suppressing the fall of luminous efficiency.

It is a figure which shows schematic structure of an example of the organic electroluminescent element which concerns on one Embodiment of this invention. It is the schematic of the apparatus which measures transient PL. It is a figure which shows an example of the attenuation curve of transient PL. It is a figure which shows the relationship between the energy level of the material contained in the light emitting layer, and energy transfer. It is a figure which shows schematic structure of an example of the organic electroluminescent element which concerns on the modification of one Embodiment of this invention.

  Hereinafter, embodiments of the organic EL device of the present invention will be described.

[First embodiment]
(Element structure of organic EL element)
The configuration of the organic EL element according to the first embodiment of the present invention will be described.
The organic EL element includes an organic layer between both an anode and a cathode. This organic layer has one or more layers composed of an organic compound. The organic layer may further contain an inorganic compound. The organic EL element of this embodiment includes at least a first organic layer and a second organic layer as organic layers. The second organic layer is provided between the first organic layer and the cathode and is adjacent to the first organic layer. The first organic layer is provided between the second organic layer and the anode and is adjacent to the second organic layer. In the organic EL element of the present embodiment, the second organic layer is a light emitting layer. Therefore, the organic layer may be composed of, for example, a first organic layer (barrier layer) and a second organic layer (light emitting layer), or a layer employed in an organic EL element, for example, a positive layer. A hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, a hole barrier layer, an electron barrier layer, and the like may be included.

In FIG. 1, schematic structure of an example of the organic EL element in this embodiment is shown.
The organic EL element 1 includes a translucent substrate 2, an anode 3, a cathode 4, and an organic layer 10 disposed between the anode 3 and the cathode 4.
The organic layer 10 includes a first organic layer 5, a second organic layer 6 adjacent to the first organic layer 5, and hole injection provided between the first organic layer 5 and the anode 3. A transport layer 7 and an electron injection / transport layer 8 provided between the second organic layer 6 and the cathode 4.
The hole injection / transport layer 7 means at least one of a hole injection layer and a hole transport layer. The electron injection / transport layer 8 means at least one of an electron injection layer and an electron transport layer. Here, when it has a positive hole injection layer and a positive hole transport layer, it is preferable that the positive hole injection layer is provided in the anode 3 side. Moreover, when it has an electron injection layer and an electron carrying layer, it is preferable that the electron injection layer is provided in the cathode 4 side. Further, each of the hole injection layer, the hole transport layer, the electron transport layer, and the electron injection layer may be composed of a single layer, or a plurality of layers may be laminated.
In the present embodiment, the electron transport layer refers to an organic layer having the highest electron mobility among the organic layers in the electron transport region existing between the light emitting layer and the cathode. When the electron transport region is composed of one layer, the layer is an electron transport layer. In addition, an electron barrier layer that does not necessarily have a high electron mobility may be provided between the light emitting layer and the electron transporting layer in order to prevent diffusion of excitation energy generated in the light emitting layer. Therefore, the organic layer adjacent to the light emitting layer does not necessarily correspond to the electron transport layer.

(Light emitting layer)
The second organic layer 6 of the organic EL element 1 according to the present embodiment contains a second material. The second organic layer 6 contains the second material at a concentration of 12% by mass or more. Furthermore, the concentration of the second material in the second organic layer 6 is preferably 16% by mass or more, and more preferably 24% by mass or more. The second material according to this embodiment is a thermally activated delayed fluorescent material.
The second organic layer 6 may contain a third material in addition to the thermally activated delayed fluorescent material. The third material is a compound having a structure different from that of the thermally activated delayed fluorescent material. The thermally activated delayed fluorescent material according to the present embodiment is a compound that hardly causes concentration quenching as described later. The second organic layer 6 may contain a matrix material for the purpose of inhibiting a change in wavelength due to exciplex formation.

-Thermally active delayed fluorescent material In this embodiment, the thermally active delayed fluorescent material contained in the second organic layer 6 is not particularly limited as long as it is a compound that can emit light by the TADF mechanism.
In this embodiment, the thermally activated delayed fluorescent material contained in the second organic layer 6 is represented by the partial structure represented by the following general formula (1) and the following general formula (2) in one molecule. It preferably has a partial structure.

In the general formula (1), CN is a cyano group.
n is an integer of 1 or more. n is preferably an integer of 1 or more and 5 or less, and more preferably an integer of 2 or more and 4 or less.
Z _{1 to} Z ₆ are each independently a nitrogen atom, a carbon atom bonded to CN, or a carbon atom bonded to another atom in the molecule of the thermally activated delayed fluorescent material. For example, when Z ₁ is a carbon atom bonded to CN among Z _{1 to} Z ₆ , at least one of the remaining five (Z _{2 to} Z ₆ ) is in the molecule of the thermally activated delayed fluorescent material. It becomes a carbon atom bonded to another atom in. The other atom may be an atom constituting a partial structure represented by the following general formula (2), or an atom constituting a linking group or a substituent interposed between the partial structure.
Z _{1 to} Z ₆ are preferably carbon atoms bonded to CN or carbon atoms bonded to other atoms in the molecule of the thermally activated delayed fluorescent material. The thermally activated delayed fluorescent material according to the present embodiment may have a 6-membered ring composed of Z _{1 to} Z ₆ as a partial structure, and the 6-membered ring is further condensed with a ring. You may have a condensed ring as a partial structure.
The 6-membered ring structure represented by the general formula (1) may construct a ring structure at an arbitrary position.

In the general formula (2), F and G each independently represent a ring structure.
m is 0 or 1.
When m is 1, Y ₁ represents a single bond, an oxygen atom, a sulfur atom, a selenium atom, a carbon atom, a silicon atom, or a germanium atom.

  When m is 0 in the general formula (2), the general formula (2) is represented by the following general formula (70).

  The ring structure F and the ring structure G in the general formula (70) are synonymous with the ring structure F and the ring structure G in the general formula (2).

  In the general formula (2), when m is 1, the general formula (2) is represented by any one of the following general formulas (71) to (77).

  The ring structure F and the ring structure G in the general formulas (71) to (77) are synonymous with the ring structure F and the ring structure G in the general formula (2).

  In the present embodiment, the ring structure F and the ring structure G are preferably a 5-membered ring or a 6-membered ring, and the 5-membered ring or 6-membered ring is preferably an unsaturated ring, More preferably, it is a member ring.

  In the present embodiment, the general formula (2) is preferably represented by at least one of the following general formula (3) and the following general formula (4).

In the general formula (4), E represents a ring structure represented by the following general formula (5) or a ring structure represented by the following general formula (6), and this ring structure E represents an adjacent ring structure. And condensed at any position.
c is an integer of 1 or more and 4 or less. When c is an integer of 2 or more and 4 or less, the plurality of ring structures E may be the same as or different from each other. Therefore, for example, when c is 2, the ring structure E may have two ring structures represented by the following general formula (5) or two ring structures represented by the following general formula (6). A combination of one ring structure represented by the following general formula (5) and one ring structure represented by the following general formula (6) may be used.

In the general formula (6), Z ₇ represents a carbon atom, a nitrogen atom, a sulfur atom, or an oxygen atom.
By holding the compounds of the general formula (1) and the general formula (2) in one molecule at the same time, it is possible to design ΔST effectively small.

  The thermally activated delayed fluorescent material according to this embodiment preferably has a structure represented by the following general formula (3a) in its molecule.

In the general formula (3a), R _{1 to} R ₉ are each independently a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted ring atom number of 5 to 30. Heterocyclic group, substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms, substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms Substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, substituted or unsubstituted alkylamino group having 2 to 30 carbon atoms, substituted or unsubstituted Substituted arylamino group having 6 to 60 carbon atoms, substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms Group, or a single bond to bond to other partial structures in the molecule of the thermal activation delayed fluorescent material.
However, at least one of R _{1 to} R ₉ is the single bond.
In the general formula (3a), at least one of the combinations of substituents selected from R _{1 to} R ₉ may be bonded to each other to form a ring structure. In the case of constructing this ring structure, that is, in the general formula (3a), among the 6-membered ring carbon atoms or 5-membered ring nitrogen atoms to which R _{1 to} R ₉ are respectively bonded, Substituents selected from R _{1 to} R ₈ and R ₉ bonded to a 5-membered ring nitrogen atom can form a ring structure. Specifically, in the general formula (3a), R ₁ and R ₂ , R ₂ and R ₃ , R ₃ and R ₄ , R ₄ and R ₅ , R ₅ and R ₆ , R ₆ and R ₇ , R Among the combinations of substituents consisting of ₇ and R ₈ , R ₈ and R ₉ , R ₁ and R ₉ , at least one set may be bonded to each other to construct a ring structure.
In the present embodiment, the ring structure constructed by bonding substituents to each other is preferably a condensed ring. For example, when the ring structure is constructed in the general formula (3a), it is preferable that a condensed 6-membered ring structure is constructed.
It is also preferable that the thermally activated delayed fluorescent material according to the present embodiment has a structure represented by the following general formula (4a) in the molecule.

In the general formula (4a), R _{11 to} R ₁₉ are each independently synonymous with R _{1 to} R ₉ in the general formula (3a).
However, at least one of R _{11 to} R ₁₉ is a single bond that binds to another partial structure in the molecule of the thermally activated delayed fluorescent material.
In the general formula (4a), at least one of the combinations of substituents selected from R _{11 to} R ₁₉ may be bonded to each other to form a ring structure.
In the general formula (4a), E represents a ring structure represented by the following general formula (5a) or a ring structure represented by the following general formula (6a), and this ring structure E is an adjacent ring structure. And condensed at any position.
c is the number of the ring structure E, and is an integer of 1 or more and 4 or less. When c is an integer of 2 or more and 4 or less, the plurality of ring structures E may be the same as or different from each other. Therefore, for example, when c is 2, the ring structure E may have two ring structures represented by the following general formula (5a) or two ring structures represented by the following general formula (6a). A combination of one ring structure represented by the following general formula (5a) and one ring structure represented by the following general formula (6a) may be used.

In the general formula (5a), R ₂₀ and R ₂₁ are each independently synonymous with R _{1 to} R ₉ , and R ₂₀ and R ₂₁ may be bonded to each other to form a ring structure. .
In the general formula (6a), Z ₈ represents CR ₂₂ R ₂₃ , NR ₂₄ , a sulfur atom, or an oxygen atom, and R _{22 to} R ₂₄ are independently the same as R _{1 to} R _9. .
In the general formula (4a), at least one of the combinations of substituents selected from R _{11 to} R ₂₄ may be bonded to each other to form a ring structure.

  The thermally activated delayed fluorescent material according to the present embodiment is preferably a compound represented by the following general formula (20).

In the general formula (20), A is represented by the general formula (1). However, in the general formula (1), CN is a cyano group, n is an integer of 1 or more, and Z _{1 to} Z ₆ are each independently a nitrogen atom, a carbon atom bonded to CN, a carbon atom bonded to R, a carbon atom bonded to L, or a carbon atom bonded to D, and each of Z _{1 to} Z ₆ Among them, there is at least one carbon atom bonded to CN, and at least one carbon atom bonded to L or D.
Each R is independently a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted carbon; An alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms, a substituted or unsubstituted carbon atom having 1 to 30 carbon atoms An alkoxy group, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkylamino group having 2 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 60 ring carbon atoms An amino group, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms.

In the general formula (20), D is represented by the general formula (2), provided that the ring structure F and the ring structure G in the general formula (2) may be unsubstituted or have a substituent. Well, m is 0 or 1, and when m is 1, Y ₁ is a single bond, oxygen atom, sulfur atom, selenium atom, carbonyl group, carbonyl group, CR ₂₁ R ₂₂ , SiR ₂₃ R _24. or an _{GeR 25 R 26, R 21 ~R} 26 are the same as defined above R. In the general formula (2), when m is 1, the general formula (2) is represented by any one of the general formulas (71) to (74) and the following general formulas (78) to (81). Is done.

In the general formula (20),
(I) When L is interposed between A and D L is a single bond, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 14 ring carbon atoms, a substituted or unsubstituted ring formation heterocyclic group having the number of atoms of _{5~14, CR 81 R 82, NR} 83, O, S, SiR 84 R 85, CR 86 R 87 -CR 88 R 89, CR 90 = CR 91, NR 92, N = CR 93 A substituted or unsubstituted aliphatic hydrocarbon ring group, or a substituted or unsubstituted aliphatic heterocyclic group,
R _{81 to} R ₉₃ are each independently synonymous with R.
In the general formula (20),
(Ii) when L is located at the end in the molecule of the thermally activated delayed fluorescent material,
L is synonymous with R.

In the general formula (20),
f is an integer of 1 or more,
e and g are each independently an integer of 0 or more.
When there are a plurality of A, the plurality of A may be the same as or different from each other.
When there are a plurality of D, the plurality of D may be the same as or different from each other.
When there are a plurality of L, the plurality of L may be the same as or different from each other.

  The general formula (20) is represented by the following general formulas (201) to (220), for example.

  In the general formula (20), in the repeating unit enclosed in parentheses having the repeating number f, D may be bonded to A via L, or via L to D. A may be bonded. For example, you may branch like the following general formula (221)-(228).

The thermally activated delayed fluorescent material according to the present embodiment is not limited to the compounds represented by the general formulas (201) to (228).
For the purpose of keeping ΔST of one molecule small, it is preferable that L is not a condensed aromatic ring in terms of molecular design, but a condensed aromatic ring is also employed as long as thermally active delayed fluorescence can be obtained. Can do. Moreover, since the molecular design which arrange | positions A and D correctly in 1 molecule is needed, it is preferable that the thermally activated delayed fluorescence material which concerns on this embodiment is a low molecular material. Therefore, the molecular weight is preferably 5000 or less, and more preferably 3000 or less. The second material according to the present embodiment includes the partial structures of the general formula (1) and the general formula (2). As a result, the organic EL element including the second material emits thermally activated delayed fluorescence. Can do.

  The thermally activated delayed fluorescent material according to this embodiment is preferably represented by the following general formula (2A).

In the general formula (2A), k is an integer of 0 or more, m is an integer of 1 or more, and n is an integer of 1 or more.
L _A is a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 30 ring carbon atoms.
CN is a cyano group.
D ₁ and D ₂ are each independently represented by the general formula (2), provided that the ring structure F and the ring structure G in the general formula (2) may be unsubstituted or have a substituent. Well, m is 0 or 1, and when m is 1, Y ₁ is a single bond, oxygen atom, sulfur atom, selenium atom, carbonyl group, carbonyl group, CR ₂₁ R ₂₂ , SiR ₂₃ R _24. or an _{GeR 25 R 26, R 21 ~R} 26 are the same as defined above R. When m is 1, in the general formula (2), when m is 1, the general formula (2) is expressed by the general formulas (71) to (74) and the general formulas (78) to (78). 81).
D ₁ and D ₂ may be the same or different. When m is 2 or more, the plurality of D ₁ may be the same as or different from each other. When k is 2 or more, the plurality of D ₂ may be the same as or different from each other.

In this embodiment, L _A is preferably a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 14 ring carbon atoms. Examples of the aromatic hydrocarbon ring having 6 to 14 ring carbon atoms include benzene, naphthalene, fluorene, and phenanthrene. More preferably, it is an aromatic hydrocarbon ring having 6 to 10 ring carbon atoms.

In the present embodiment, in the general formula (2A), L the D ₁ or the D ₂ is coupled to the first carbon atom of which are building an aromatic hydrocarbon ring represented by _A, the first The CN is preferably bonded to the second carbon atom adjacent to the carbon atom. For example, the compounds according to the present embodiment, as the partial structure represented by the following general formula (1a), wherein D is attached to the first carbon atom C _1, the first next to the carbon atoms C ₁ it is preferable that the second cyano group to the carbon atom C ₂ is bonded. D in the following general formula (1a) has the same meaning as D ₁ or D ₂ . In the following general formula (1a), a wavy line portion represents a bond with another structure or atom.

And D ₁ or D ₂ having a skeleton such as formula (3) or the general formula (4), bonded to the aromatic hydrocarbon ring is a cyano group represented by adjacent said L _A As a result, the value of ΔST of the compound can be reduced.

In the present embodiment, m is preferably an integer of 2 or more. If the said D ₁ of the 2 or more aromatic hydrocarbon ring represented by L _A is attached, a plurality of D ₁ may be a different structure may be the same structure.

-3rd material It is preferable that the 3rd material which concerns on this embodiment has a triplet level larger than the thermally activated delayed fluorescence material which concerns on this embodiment. Suitable compounds as the third material include aromatic hydrocarbon derivatives, heterocyclic derivatives, arylamine derivatives, porphyrin compounds, various metal complexes, phosphorus compounds, polymer compounds, and the like. Specific examples suitable as the third material include the following compounds.
Examples of the aromatic hydrocarbon derivative include compounds having a high triplet level such as benzene, naphthalene, phenanthrene, triphenylene, and fluorene.
Heterocyclic derivatives include pyrrole derivatives, indole derivatives, carbazole derivatives, furan derivatives, benzofuran derivatives, dibenzofuran derivatives, thiophene derivatives, benzothiophene derivatives, dibenzothiophene derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, benzs. Examples include imidazole derivatives, imidazopyridine derivatives, and indolizine derivatives.
Examples of porphyrin compounds include compounds such as phthalocyanine derivatives.
Examples of the various metal complexes include metal complexes of quinolinol derivatives, metal complexes having metal phthalocyanine, benzoxazole or benzothiazole as a ligand.
Examples of the phosphorus compound include compounds such as phosphine oxide.
Examples of the polymer compound include poly (N-vinylcarbazole) derivatives, aniline copolymers, thiophene oligomers, conductive polymer oligomers such as polythiophene, polythiophene derivatives, polyphenylene derivatives, polyphenylene vinylene derivatives, polyfluorene derivatives, and the like. .

Further, as the third material according to the present embodiment, in addition to the above materials, for example, the following fluorescent light emitting material can be used. In this case, it is preferable that the third material according to the present embodiment has a singlet level smaller than that of the thermally activated delayed fluorescent material according to the present embodiment.
An aromatic amine derivative or the like can be used as the green fluorescent material. Specifically, N- (9,10-diphenyl-2-anthryl) -N, 9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N- [9,10-bis (1,1 '-Biphenyl-2-yl) -2-anthryl] -N, 9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N- (9,10-diphenyl-2-anthryl) -N, N ', N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N- [9,10-bis (1,1'-biphenyl-2-yl) -2-anthryl] -N, N' , N′-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), N- [9,10-bis (1,1′-biphenyl-2-yl)]-N- [4- (9H-carbazole) -9-yl) phenyl ] -N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N, N, 9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), and the like.
Tetracene derivatives, diamine derivatives, and the like can be used as red fluorescent materials. Specifically, N, N, N ′, N′-tetrakis (4-methylphenyl) tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N, N, N ′, And N′-tetrakis (4-methylphenyl) acenaphtho [1,2-a] fluoranthene-3,10-diamine (abbreviation: p-mPhAFD).

  The third material may be the same compound as the first material.

  As the third material, various compounds may be used alone or in combination of two or more.

(First organic layer)
The first organic layer 5 of the organic EL element 1 according to the present embodiment contains a first material. Although it does not specifically limit as a 1st material contained in the 1st organic layer 5, It is preferable that they are compounds other than an amine compound. For example, a carbazole derivative, a dibenzofuran derivative, and a dibenzothiophene derivative can be used as the first material, but the first material is not limited to these derivatives.

  In the present embodiment, the first material is a compound containing at least one of a partial structure represented by the following general formula (21) and a partial structure represented by the following general formula (22) in one molecule. Preferably there is.

In the general formula (21),
Y _{21 to} Y ₂₆ are each independently a nitrogen atom or a carbon atom bonded to another atom in the molecule of the first material,
However, at least one of Y _{21 to} Y ₂₆ is a carbon atom bonded to another atom in the molecule of the first material,
In the general formula (22),
Y _{31 to} Y ₃₈ are each independently a nitrogen atom or a carbon atom bonded to another atom in the molecule of the first material,
However, at least one of Y _{31 to} Y ₃₈ is a carbon atom bonded to another atom in the molecule of the first material,
X ₂ is a nitrogen atom, an oxygen atom, or a sulfur atom.

In the general formula (22), at least two of Y _{31 to} Y ₃₈ are carbon atoms bonded to other atoms in the molecule of the first material, and a ring structure including the carbon atoms is constructed. It is also preferable.
For example, the partial structure represented by the general formula (22) includes partial structures represented by the following general formulas (221), (222), (223), (224), (225), and (226). It is preferably any one selected from the group.

In the general formulas (221) to (226),
X ₂ is a nitrogen atom, an oxygen atom, or a sulfur atom,
Y _{31 to} Y ₃₈ are each independently a nitrogen atom or a carbon atom bonded to another atom in the molecule of the first material,
X ₇ is a nitrogen atom, an oxygen atom, a sulfur atom, or a carbon atom,
Y _{71 to} Y ₇₄ are each independently a nitrogen atom or a carbon atom bonded to another atom in the molecule of the first material.
In the present embodiment, the first material preferably has a partial structure represented by the general formula (223) among the general formulas (221) to (226).

In this embodiment, the partial structure represented by the general formula (21) is at least selected from the group consisting of a group represented by the following general formula (23) and a group represented by the following general formula (24). It is preferable that any group is contained in the first material.
As represented by the following general formula (23) and the following general formula (24), the fact that the bonding sites are located at the meta positions can keep the energy gap T _77K (M1) at 77 [K] high. Therefore, it is preferable as the first material.

In the general formula (23) and the general formula (24),
Y ₂₁ , Y ₂₂ , Y ₂₄ and Y ₂₆ are each independently a nitrogen atom or CR ₃₁ ;
R ₃₁ is a hydrogen atom or a substituent, and when R ₃₁ is a substituent, the substituent is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, a substituted or unsubstituted ring A heterocyclic group having 5 to 30 atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted carbon number 3 to 30 Selected from the group consisting of a cycloalkyl group, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted silyl group, a substituted germanium group, a substituted phosphine oxide group, a halogen atom, a cyano group, a nitro group, and a carboxy group. Provided that the substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms in R ₃₁ is preferably a non-condensed ring.
In the said General formula (23) and the said General formula (24), a wavy line part represents the coupling | bond part with the other atom or other structure in the molecule | numerator of said 1st material.

In the present embodiment, in the general formula (23), Y ₂₁ , Y ₂₂ , Y ₂₄ and Y ₂₆ are preferably independently CR ₃₁ , and a plurality of R ₃₁ may be the same. May be different.
In the present embodiment, in the general formula (24), Y ₂₂ , Y ₂₄ and Y ₂₆ are preferably independently CR ₃₁ , and a plurality of R ₃₁ are the same or different. May be.

In the present embodiment, the substituted germanium group is preferably represented by -Ge (R ₁₀₁ ) ₃ . R ₁₀₁ is each independently a substituent. Substituent R ₁₀₁ is preferably a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms. The plurality of R ₁₀₁ may be the same as or different from each other.

  In this embodiment, the partial structure represented by the general formula (22) includes a group represented by the following general formula (25), a group represented by the following general formula (26), and the following general formula (27). And at least any one selected from the group consisting of a group represented by the following general formula (28), a group represented by the following general formula (29), and a group represented by the following general formula (20a) It is preferable to be contained in the first material as such a group.

In the general formulas (25) to (29) and (20a),
Y ₃₁ , Y ₃₂ , Y ₃₃ , Y ₃₄ , Y ₃₅ , Y ₃₆ , Y ₃₇ , and Y ₃₈ are each independently a nitrogen atom or CR ₃₂ ;
R ₃₂ is a hydrogen atom or a substituent, and when R ₃₂ is a substituent, the substituent is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, a substituted or unsubstituted ring. A heterocyclic group having 5 to 30 atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted carbon number 3 to 30 Selected from the group consisting of a cycloalkyl group, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted silyl group, a substituted germanium group, a substituted phosphine oxide group, a halogen atom, a cyano group, a nitro group, and a carboxy group. Provided that the substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms in R ₃₂ is preferably a non-condensed ring,
In the general formulas (25) and (26), X ₂ is a nitrogen atom,
In the general formulas (27) to (29) and (20a), X ₂ is NR ₃₃ , an oxygen atom or a sulfur atom,
R ₃₃ is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted carbon group having 1 to 30 carbon atoms. Alkyl group, substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, substituted silyl A substituent selected from the group consisting of a group, a substituted germanium group, a substituted phosphine oxide group, a fluorine atom, a cyano group, a nitro group, and a carboxy group, provided that the number of substituted or unsubstituted ring carbons in R ₃₃ The 6-30 aromatic hydrocarbon group is preferably a non-condensed ring.
In the general formulas (25) to (29) and (20a), the wavy line portion represents a bonding point with another atom or another structure in the molecule of the first material.

In the present embodiment, in the general formula (25), Y _{31 to} Y ₃₈ are preferably each independently CR _{32. In the} general formula (26) and the general formula (27), Y ₃₁ to Y ₃₈ Y ₃₅ , Y ₃₇ and Y ₃₈ are preferably each independently CR _{32. In the} general formula (28), Y ₃₁ , Y ₃₂ , Y ₃₄ , Y ₃₅ , Y ₃₇ and Y ₃₈ are each Independently, it is preferably CR ₃₂ , and in the general formula (29), Y _{32 to} Y ₃₈ are each independently preferably CR ₃₂ , and in the general formula (20a), Y _{32 to} Y Each of ₃₇ is preferably independently CR ₃₂ , and the plurality of R ₃₂ may be the same or different.

In the present embodiment, the first material also preferably includes a group represented by the following general formula (20A).
It is preferable for the first material to be located as represented by the following general formula (20A) because the energy gap T _77K at 77 [K] can be kept high.

In the general formula (20A),
Y ₂₁ , Y ₂₂ , Y ₂₄ and Y ₂₆ are each independently a nitrogen atom or CR ₃₁ ;
Y ₃₁ , Y ₃₂ and Y _{34 to} Y ₃₈ are each independently a nitrogen atom, CR ₃₂ , or a carbon atom bonded to another atom in the molecule of the first material;
R ₃₁ and R ₃₂ are each independently a hydrogen atom or a substituent, and when R ₃₁ and R ₃₂ are a substituent, the substituent is a substituted or unsubstituted aromatic group having 6 to 30 ring carbon atoms. A hydrocarbon group, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, Substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, substituted silyl group, substituted germanium group, substituted phosphine oxide group, fluorine atom, cyano group, nitro group , and a substituent selected from the group consisting of a carboxy group, provided that the R ₃₁ and the R substituted or unsubstituted in the ₃₂ ring carbon 6-3 Aromatic hydrocarbon group is preferably a non-fused rings,
X ₂ is NR ₃₃ , an oxygen atom, or a sulfur atom,
R ₃₃ is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted carbon group having 1 to 30 carbon atoms. Alkyl group, substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, substituted silyl A substituent selected from the group consisting of a group, a substituted germanium group, a substituted phosphine oxide group, a fluorine atom, a cyano group, a nitro group, and a carboxy group, provided that the number of substituted or unsubstituted ring carbons in R ₃₃ The 6-30 aromatic hydrocarbon group is preferably a non-condensed ring,
Y ₂₂ and Y ₃₄ may be cross-linked via an oxygen atom, a sulfur atom, or CR ₅₁ R ₅₂ ,
Y ₂₄ and Y ₃₂ may be cross-linked via an oxygen atom, a sulfur atom, or CR ₅₃ R ₅₄ ,
R _{51 to} R ₅₄ are each independently synonymous with the substituent in the case where R ₃₃ is a substituent.
In the general formula (20A), a wavy line portion represents a bonding site with another atom or another structure in the molecule of the first material.

For example, in the general formula _(20A), and _{Y 22} and _{Y 34} is an oxygen atom, if that is crosslinked through a sulfur atom or a _CR 51 _{R 52,} represented by the following general formula (20A-1).

However, in the general formula _{(20A-1), Z 21} represents an oxygen atom, a sulfur atom, or a _CR 51 _{R 52.} In the general formula (20A-1), X ₂ , Y ₂₁ , Y ₂₄ , Y ₂₆ , Y ₃₁ , Y ₃₂ , and Y _{35 to} Y ₃₈ are X ₂ , Y ₂₁ , and Y in the general formula (20A), respectively. _{Y 24, Y 26, Y 31} , Y 32, the same meaning as Y 35 _{to Y 38.}

  In this embodiment, it is preferable that the partial structure represented by the general formula (223) is included in the first material as a group represented by the following general formula (223A).

In the general formula (223A), Y ₃₃ , Y ₃₄ , Y ₃₅ , Y ₃₇ , Y ₃₈ , Y ₇₁ , Y ₇₂ , and Y ₇₄ are each independently a nitrogen atom or CR ₂₂₁ , and R ₂₂₁ is the same meaning as _{R 32} in the general formula (25).
X ₂ is NR ₂₂₂ , an oxygen atom, or a sulfur atom,
X ₇ is NR ₂₂₃ , an oxygen atom, a sulfur atom, or CR ₂₂₄ R ₂₂₅ , and R _{222 to} R ₂₂₅ are each independently synonymous with R ₃₃ in the general formula (27).
X ₂ and X ₇ are preferably oxygen atoms. Y ₃₃ , Y ₃₄ , Y ₃₅ , Y ₃₇ , Y ₃₈ , Y ₇₁ , Y ₇₂ , and Y ₇₄ are preferably CR ₂₂₁ .

In the present embodiment, the first material preferably includes a group represented by the following general formula (20B).
Positioning the bonding site as represented by the following general formula (20B) is preferable as the first material because the energy gap T _77K at 77 [K] can be kept high.

In the general formula (20B),
Y ₂₁ , Y ₂₂ , Y ₂₄ and Y ₂₆ are each independently a nitrogen atom or CR ₃₁ ;
Y ₃₁ , Y ₃₂ , Y ₃₄ , Y ₃₅ , Y ₃₇ and Y ₃₈ are each independently a nitrogen atom or CR ₃₂ ;
Y _{41 to} Y ₄₅ , Y ₄₇ and Y ₄₈ are each independently a nitrogen atom, CR ₃₄ , or a carbon atom bonded to another atom in the molecule of the first material;
R ₃₁ , R ₃₂ , and R ₃₄ are each independently a hydrogen atom or a substituent, and when R ₃₁ , R _32, and R ₃₄ are substituents, the substituent is a substituted or unsubstituted ring-forming carbon number. 6-30 aromatic hydrocarbon groups, substituted or unsubstituted heterocyclic groups having 5 to 30 ring atoms, substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted 1 to 3 carbon atoms 30 fluoroalkyl groups, substituted or unsubstituted cycloalkyl groups having 3 to 30 carbon atoms, substituted or unsubstituted aralkyl groups having 7 to 30 carbon atoms, substituted silyl groups, substituted germanium groups, substituted phosphine oxide groups, fluorine atoms , is a substituent selected from the group consisting of cyano group, a nitro group and a carboxy group, wherein the substituent at the _{R 31,} wherein _{R 32,} wherein _{R 34} or Aromatic hydrocarbon group-substituted ring-forming having 6 to 30 carbon atoms is preferably a non-fused rings,
X ₂ is NR ₃₃ , an oxygen atom, or a sulfur atom,
X ₃ is NR ₃₅ , an oxygen atom, or a sulfur atom,
R ₃₃ and R ₃₅ are each independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, substituted or unsubstituted A substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted carbon number 7 to 7 30 substituents selected from the group consisting of an aralkyl group, a substituted silyl group, a substituted germanium group, a substituted phosphine oxide group, a fluorine atom, a cyano group, a nitro group, and a carboxy group, provided that R ₃₃ and R The substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms in ₃₅ is preferably a non-condensed ring,
Y ₂₂ and Y ₃₄ may be cross-linked via an oxygen atom, a sulfur atom, or CR ₅₁ R ₅₂ ,
Y ₂₄ and Y ₃₂ may be cross-linked via an oxygen atom, a sulfur atom, or CR ₅₃ R ₅₄ ,
R _{51 to} R ₅₄ are each independently synonymous with the substituent in the case where R ₃₃ and R ₃₅ are substituents.
In the general formula (20B), a wavy line portion represents a bonding site with another atom or another structure in the molecule of the first material.

For example, in the general formula _(20B), and _{Y 22} and _{Y 34} is an oxygen atom, if that is crosslinked through a sulfur atom or a _CR 51 _{R 52,} represented by the following formula (20B-1).

However, in the general formula _{(20B-1), Z 22} represents an oxygen atom, a sulfur atom, or a _CR 51 _{R 52.} In the general formula (20B-1), X ₂ , X ₃ , Y ₂₁ , Y ₂₄ , Y ₂₆ , Y ₃₁ , Y ₃₂ , Y ₃₅ , Y ₃₇ , Y ₃₈ , Y _{41 to} Y ₄₅ , Y ₄₇ and Y _{47 48} represents X ₂ , X ₃ , Y ₂₁ , Y ₂₄ , Y ₂₆ , Y ₃₁ , Y ₃₂ , Y ₃₅ , Y ₃₇ , Y ₃₈ , Y _{41 to} Y ₄₅ , Y _{47 in the} general formula (20B), respectively. And Y ₄₈ .

In the present embodiment, the first material preferably includes a group represented by the following general formula (20C).
Positioning the bonding site as represented by the following general formula (20C) is preferable as the first material because the energy gap T _77K at 77 [K] can be kept high.

In the general formula (20C),
Y ₂₁ , Y ₂₂ , Y ₂₄ and Y ₂₆ are each independently a nitrogen atom or CR ₃₁ ;
Y ₅₁ , Y ₅₃ , Y ₅₄ and Y ₅₅ are each independently a nitrogen atom or CR ₃₆ ,
R ₃₁ and R ₃₆ are each independently a hydrogen atom or a substituent. When R ₃₁ and R ₃₆ are a substituent, the substituent is a substituted or unsubstituted aromatic group having 6 to 30 ring carbon atoms. A hydrocarbon group, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, Substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, substituted silyl group, substituted germanium group, substituted phosphine oxide group, fluorine atom, cyano group, nitro group , and a substituent selected from the group consisting of a carboxy group, provided that the R ₃₁ and the R substituted or unsubstituted in the ₃₆ ring carbon 6-3 Aromatic hydrocarbon group is preferably a non-fused rings,
Y ₂₂ and Y ₅₁ may be cross-linked via an oxygen atom, a sulfur atom, or CR ₅₅ R ₅₆ ,
Y ₂₄ and Y ₅₅ may be cross-linked via an oxygen atom, a sulfur atom, or CR ₅₇ R ₅₈ ,
R ₅₅ to R ₅₈ are each independently a _substituent, the substituent in R 55 _{to R 58} is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, a substituted or unsubstituted A heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted carbon number 3 to 3 Selected from the group consisting of 30 cycloalkyl groups, substituted or unsubstituted aralkyl groups having 7 to 30 carbon atoms, substituted silyl groups, substituted germanium groups, substituted phosphine oxide groups, fluorine atoms, cyano groups, nitro groups, and carboxy groups is a substituent, provided that an aromatic hydrocarbon group substituted or unsubstituted ring formed of 6 to 30 carbon atoms for the R ₅₅ to R ₅₈ is a non-fused ring this It is preferred.
In the general formula (20C), a wavy line portion represents a bonding site with another atom or another structure in the molecule of the first material.

For example, in the general formula (20C), when Y ₂₂ and Y ₅₁ are cross-linked via an oxygen atom, a sulfur atom, or CR ₅₅ R ₅₆ , they are represented by the following general formula (20C-1). .

However, in the general formula _{(20C-1), Z 23} represents an oxygen atom, a sulfur atom, or a _CR 55 _{R 56.} In Formula _{(20C-1), Y 21} , Y 24, Y 26 and _Y 53 _{to Y 55,} respectively, and _{Y 21, Y 24, Y 26} and _Y 53 _{to Y 55} in the general formula (20C) It is synonymous.

In the present embodiment, the first material preferably includes a group represented by the following general formula (20D).
Positioning the bonding site as represented by the following general formula (20D) is preferable as the first material because the energy gap T _77K at 77 [K] can be kept high.

In the general formula (20D),
Y ₂₁ , Y ₂₂ , Y ₂₄ and Y ₂₆ are each independently a nitrogen atom or CR ₃₁ ;
Y ₅₁ , Y ₅₃ , Y ₅₄ and Y ₅₅ are each independently a nitrogen atom or CR ₃₆ ,
Y _{31 to} Y ₃₅ , Y ₃₇ and Y ₃₈ are each independently a nitrogen atom, CR ₃₂ , or a carbon atom bonded to another atom in the molecule of the first material;
R ₃₁ , R ₃₂ and R ₃₆ are each independently a hydrogen atom or a substituent, and when R ₃₁ , R ₃₂ and R ₃₆ are a substituent, the substituent is a substituted or unsubstituted ring-forming carbon number. 6-30 aromatic hydrocarbon groups, substituted or unsubstituted heterocyclic groups having 5 to 30 ring atoms, substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted 1 to 3 carbon atoms 30 fluoroalkyl groups, substituted or unsubstituted cycloalkyl groups having 3 to 30 carbon atoms, substituted or unsubstituted aralkyl groups having 7 to 30 carbon atoms, substituted silyl groups, substituted germanium groups, substituted phosphine oxide groups, fluorine atoms , a cyano group, a substituent selected from the group consisting of nitro groups and carboxy groups, with the proviso that the R _31, also substituted at the R ₃₂ and the R ₃₆ Ku unsubstituted aromatic hydrocarbon group having ring-forming having 6 to 30 carbon atoms is preferably a non-fused rings,
X ₂ is NR ₃₃ , an oxygen atom, or a sulfur atom,
R ₃₃ is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted carbon group having 1 to 30 carbon atoms. Alkyl group, substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, substituted silyl A substituent selected from the group consisting of a group, a substituted germanium group, a substituted phosphine oxide group, a fluorine atom, a cyano group, a nitro group, and a carboxy group, provided that the number of substituted or unsubstituted ring carbons in R ₃₃ The 6-30 aromatic hydrocarbon group is preferably a non-condensed ring,
Y ₂₂ and Y ₅₁ may be cross-linked via an oxygen atom, a sulfur atom, or CR ₅₅ R ₅₆ ,
Y ₂₄ and Y ₅₅ may be cross-linked via an oxygen atom, a sulfur atom, or CR ₅₇ R ₅₈ ,
Y ₅₁ and Y ₃₇ may be cross-linked via an oxygen atom, a sulfur atom, or CR ₅₉ R ₆₀ ,
Y ₅₃ and Y ₃₅ may be cross-linked via an oxygen atom, a sulfur atom, or CR ₆₁ R ₆₂ ,
R _{55 to} R ₆₂ are each independently synonymous with the substituent in the case where R ₃₃ is a substituent.
In the general formula (20D), the wavy line part represents a bonding site with another atom or another structure in the molecule of the first material.

For example, in the general formula (20D), when Y ₂₂ and Y ₅₁ are cross-linked via an oxygen atom, a sulfur atom, or CR ₅₅ R ₅₆ , they are represented by the following general formula (20D-1).

However, in the general formula _{(20D-1), Z 24} represents an oxygen atom, a sulfur atom, or a _CR 55 _{R 56.} In the general formula (20D-1), X ₂ , Y ₂₁ , Y ₂₄ , Y ₂₆ , Y _{31 to} Y ₃₅ , Y ₃₇ , Y ₃₈ and Y _{53 to} Y ₅₅ are respectively represented by the general formula (20D). X _{2, Y} 21, a _{Y 24, Y 26, Y 31} ~Y 35, Y 37, the same meaning as _{Y 38} and _Y 53 _{to Y 55.}

For example, in the general formula (20D), when Y ₅₁ and Y ₃₇ are cross-linked via an oxygen atom, a sulfur atom, or CR ₅₉ R ₆₀ , they are represented by the following general formula (20D-2). .

However, in the general formula _{(20D-2), Z 25} represents an oxygen atom, a sulfur atom, or a _CR 59 _{R 60.} In the general formula (20D-2), X ₂ , Y ₂₁ , Y ₂₂ , Y ₂₄ , Y ₂₆ , Y _{31 to} Y ₃₅ , Y ₃₈ and Y _{53 to} Y ₅₅ are respectively in the general formula (20D). _{X 2, Y 21, Y 22} , Y 24, Y 26, Y 31 is synonymous with to Y _{35, Y 38} and _Y 53 _{to Y 55.}

In the present embodiment, the first material preferably includes a group represented by the following general formula (20E).
Positioning the bonding site as represented by the following general formula (20E) is preferable as the third material because the energy gap T _77K at 77 [K] can be kept high.

In the general formula (20E), Y ₃₁ , Y ₃₂ , Y ₃₄ , Y ₃₅ , Y ₃₇ and Y ₃₈ are each independently a nitrogen atom or CR ₃₂ ,
Y _{41 to} Y ₄₅ , Y ₄₇ and Y ₄₈ are each independently a nitrogen atom, CR ₃₄ , or a carbon atom bonded to another atom in the molecule of the first material;
R ₃₂ and R ₃₄ are each independently a hydrogen atom or a substituent, and when R ₃₂ and R ₃₄ are a substituent, the substituent is a substituted or unsubstituted aromatic group having 6 to 30 ring carbon atoms. A hydrocarbon group, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, Substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, substituted silyl group, substituted germanium group, substituted phosphine oxide group, fluorine atom, cyano group, nitro group , and a substituent selected from the group consisting of a carboxy group, provided that the R ₃₂ and the R substituted or unsubstituted in the ₃₄ ring carbon 6-3 Aromatic hydrocarbon group is preferably a non-fused rings,
X ₂ is NR ₃₃ , an oxygen atom, or a sulfur atom,
X ₃ is NR ₃₅ , an oxygen atom, or a sulfur atom,
R ₃₃ and R ₃₅ are each independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, substituted or unsubstituted A substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted carbon number 7 to 7 30 substituents selected from the group consisting of an aralkyl group, a substituted silyl group, a substituted germanium group, a substituted phosphine oxide group, a fluorine atom, a cyano group, a nitro group, and a carboxy group, provided that R ₃₃ and R The substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms in ₃₅ is preferably a non-condensed ring.
In the general formula (20E), a wavy line portion represents a bonding site with another atom or another structure in the molecule of the first material.

  In the present embodiment, the first material is a group represented by the following general formula (20F), a group represented by the following general formula (20G), and a group represented by the following general formula (20H). At least any group may be contained.

In the general formula (20F), the general formula (20G), and the general formula (20H), Y ₂₁ , Y ₂₂ , Y ₂₄ , Y ₂₆ , Y _{31 to} Y ₃₈ , Y _{41 to} Y ₄₈ , Y _{61 to} Y ₆₅ , Y ₆₇ and Y ₆₈ are each independently a nitrogen atom, CR ₃₇ , or a carbon atom bonded to another atom in the molecule of the first material;
R ₃₇ each independently represents a hydrogen atom or a substituent, and when R ₃₇ is a substituent, the substituent is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, a substituted or Unsubstituted heterocyclic group having 5 to 30 ring atoms, substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, substituted or unsubstituted carbon It consists of a cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted silyl group, a substituted germanium group, a substituted phosphine oxide group, a fluorine atom, a cyano group, a nitro group, and a carboxy group. is a substituent selected from the group that, however, an aromatic hydrocarbon group substituted or unsubstituted ring formed of 6 to 30 carbon atoms for the R ₃₇ is a non-fused ring Preferably,
X ₂ and X ₄ are each independently NR ₃₈ , an oxygen atom, or a sulfur atom, and R ₃₈ is each independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, Substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, substituted or unsubstituted A cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted silyl group, a substituted germanium group, a substituted phosphine oxide group, a fluorine atom, a cyano group, a nitro group, and a carboxy group It is a substituent selected from the group consisting of, but, aromatic hydrocarbon group or a substituted or unsubstituted ring formed of 6 to 30 carbon atoms for the R ₃₈ represents, uncondensed Is preferably ring,
In the general formula (20F), the general formula (20G), and the general formula (20H), a wavy line portion represents a bonding point with another atom or another structure in the molecule of the first material.

In the present embodiment, X ₂ is preferably an oxygen atom or a sulfur atom, and more preferably an oxygen atom.
X ₃ is preferably an oxygen atom or a sulfur atom, and more preferably an oxygen atom.
X ₄ is preferably an oxygen atom or a sulfur atom, and more preferably an oxygen atom.
Further, it is preferable that the X ₂ and the X ₃ is an oxygen atom.
Further, it is preferable that the X ₂ and the X ₄ is an oxygen atom.

In the present embodiment, R ₃₁ , R ₃₂ , R ₃₄ , R ₃₆ , R ₃₇ , and R ₂₂₁ are each independently a hydrogen atom or a substituent, and R ₃₁ , R ₃₂ , R ₃₄ , R ₃₆ , R ₃₇ , and R ₂₂₁ are a fluorine atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, or a substituted or unsubstituted ring carbon number. A substituent selected from the group consisting of an aromatic hydrocarbon group having 6 to 30 and a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms is preferable. R ₃₁ , R ₃₂ , R ₃₄ , R ₃₆ , R ₃₇ , and R ₂₂₁ are a hydrogen atom, a cyano group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, Alternatively, it is more preferably a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms. However, the substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms in R ₃₁ , R ₃₂ , R ₃₄ , R ₃₆ , R ₃₇ , and R ₂₂₁ is a non-condensed ring. Preferably there is.

In the present embodiment, R ₃₃ , R ₃₅ , R ₃₈ , and R _{222 to} R ₂₂₅ are each independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms and a substituted group. Or a substituent selected from the group consisting of an unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 20 ring carbon atoms, and It is more preferably a substituent selected from the group consisting of substituted or unsubstituted heterocyclic groups having 5 to 20 ring atoms. However, the substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms in R ₃₃ , R ₃₅ , R ₃₈ , and R _{222 to} R ₂₂₅ is preferably a non-condensed ring.

In the present embodiment, each of R _{51 to} R ₆₂ independently represents a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, And a substituent selected from the group consisting of a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms and a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, substituted or unsubstituted It is more preferably a substituent selected from the group consisting of an aromatic hydrocarbon group having 6 to 20 ring carbon atoms and a substituted or unsubstituted heterocyclic group having 5 to 20 ring atoms. However, the substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms in R _{51 to} R ₆₂ is preferably a non-condensed ring.

In the present embodiment, the first material is also preferably an aromatic hydrocarbon compound or an aromatic heterocyclic compound.
Moreover, in this embodiment, it is preferable that the first material does not have a condensed aromatic hydrocarbon ring in the molecule.

-Manufacturing method of 1st material Said 1st material is manufactured by the method as described in international publication 2012/153780 (WO2012 / 153780A1) and international publication 2013/038650 (WO2013-038650A1) etc., for example. be able to.

  Examples of substituents in the first material according to the present embodiment are as follows, for example, but the present invention is not limited to these examples.

Specific examples of the aromatic hydrocarbon group (sometimes referred to as an aryl group) include a phenyl group, a tolyl group, a xylyl group, a naphthyl group, a phenanthryl group, a pyrenyl group, a chrysenyl group, and a benzo [c] phenanthryl group. , Benzo [g] chrysenyl group, benzoanthryl group, triphenylenyl group, fluorenyl group, 9,9-dimethylfluorenyl group, benzofluorenyl group, dibenzofluorenyl group, biphenyl group, terphenyl group, quarterphenyl Group, fluoranthenyl group, etc., preferably phenyl group, biphenyl group, terphenyl group, quarterphenyl group, naphthyl group, triphenylenyl group, fluorenyl group and the like.
Examples of the aromatic hydrocarbon group having a substituent include a tolyl group, a xylyl group, and a 9,9-dimethylfluorenyl group.
As specific examples indicate, aryl groups include both fused and non-fused aryl groups.
As the aromatic hydrocarbon group, a phenyl group, a biphenyl group, a terphenyl group, a quarterphenyl group, a naphthyl group, a triphenylenyl group, and a fluorenyl group are preferable.

Specific examples of the aromatic heterocyclic group (sometimes referred to as heteroaryl group, heteroaromatic ring group, or heterocyclic group) include pyrrolyl group, pyrazolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, pyridyl group. , Triazinyl group, indolyl group, isoindolyl group, imidazolyl group, benzimidazolyl group, indazolyl group, imidazol [1,2-a] pyridinyl group, furyl group, benzofuranyl group, isobenzofuranyl group, dibenzofuranyl group, azadibenzo Furanyl group, thiophenyl group, benzothiophenyl group, dibenzothiophenyl group, azadibenzothiophenyl group, quinolyl group, isoquinolyl group, quinoxalinyl group, quinazolinyl group, naphthyridinyl group, carbazolyl group, azacarbazolyl group, phenanthridinyl group, An acridinyl group, Enanthrolinyl group, phenazinyl group, phenothiazinyl group, phenoxazinyl group, oxazolyl group, oxadiazolyl group, furazanyl group, benzoxazolyl group, thienyl group, thiazolyl group, thiadiazolyl group, benzthiazolyl group, triazolyl group, tetrazolyl group, etc. Preferred examples include a dibenzofuranyl group, a dibenzothiophenyl group, a carbazolyl group, a pyridyl group, a pyrimidinyl group, a triazinyl group, an azadibenzofuranyl group, and an azadibenzothiophenyl group.
As the aromatic heterocyclic group, dibenzofuranyl group, dibenzothiophenyl group, carbazolyl group, pyridyl group, pyrimidinyl group, triazinyl group, azadibenzofuranyl group, azadibenzothiophenyl group are preferable, dibenzofuranyl group, dibenzofuranyl group A thiophenyl group, an azadibenzofuranyl group, and an azadibenzothiophenyl group are more preferable.

In the first material of the present embodiment, the substituted silyl group is preferably a substituted or unsubstituted trialkylsilyl group, a substituted or unsubstituted arylalkylsilyl group, or a substituted or unsubstituted triarylsilyl group. .
Specific examples of the substituted or unsubstituted trialkylsilyl group include a trimethylsilyl group and a triethylsilyl group.
Specific examples of the substituted or unsubstituted arylalkylsilyl group include a diphenylmethylsilyl group, a ditolylmethylsilyl group, and a phenyldimethylsilyl group.
Specific examples of the substituted or unsubstituted triarylsilyl group include a triphenylsilyl group and a tolylsilylsilyl group.

In the first material of the present embodiment, the substituted phosphine oxide group is preferably a substituted or unsubstituted diarylphosphine oxide group.
Specific examples of the substituted or unsubstituted diarylphosphine oxide group include a diphenylphosphine oxide group and a ditolylphosphine oxide group.

  The example of the 1st material which concerns on this embodiment is shown below. The first material in the present invention is not limited to these examples.

(Relationship between the first material and the second material)
In the organic EL element 1 of the present embodiment, the ionization potential IP _B of the first material included in the first organic layer 5 and the second material (thermal activity) included in the second organic layer 6 and the ionization potential IP _T of delayed fluorescence material), satisfies the following equation (equation 1).

IP _B > IP _T (1)

  In the present embodiment, the ionization potential of the first material is preferably 6.0 eV or more. The ionization potential of the second material (thermally active delayed fluorescent material) is preferably 5.9 eV or less. Further, the ionization potential of the first material is preferably 6.0 eV or more, and the ionization potential of the second material (thermally activated delayed fluorescent material) is preferably 5.9 eV or less.

  In the present embodiment, the first material and the second material (thermally activated delayed fluorescent material) that satisfy the above-described conditions are used. The reason why such a combination is preferable can be explained by measuring the transient PL.

FIG. 2 shows a schematic diagram of an apparatus for measuring transient PL.
The transient PL measurement apparatus 100 of the present embodiment includes a pulse laser unit 101 that can irradiate light of a predetermined wavelength, a sample chamber 102 that houses a measurement sample, a spectrometer 103 that splits light emitted from the measurement sample, A streak camera 104 for forming a two-dimensional image and a personal computer 105 for capturing and analyzing the two-dimensional image are provided. Note that the measurement of the transient PL is not limited to the apparatus described in this embodiment.
The sample accommodated in the sample chamber 102 is obtained by forming a thin film in which a doping material is doped at a concentration of 12 mass% with respect to a matrix material on a quartz substrate.
The thin film sample accommodated in the sample chamber 102 is excited by being irradiated with a pulse laser from the pulse laser unit 101. The emitted light is extracted from the direction of 90 degrees of the excitation light, dispersed by the spectroscope 103, and a two-dimensional image is formed in the streak camera 104. As a result, a two-dimensional image can be obtained in which the vertical axis corresponds to time, the horizontal axis corresponds to wavelength, and the bright spot corresponds to emission intensity. When this two-dimensional image is cut out along a predetermined time axis, an emission spectrum in which the vertical axis represents the emission intensity and the horizontal axis represents the wavelength can be obtained. When the two-dimensional image is cut out along the wavelength axis, an attenuation curve can be obtained in which the vertical axis represents the logarithm of the emission intensity and the horizontal axis represents time.

  For example, the thin film sample A was prepared as described above using the following reference compound H1 as a matrix material and the following compound D1 as a doping material, and transient PL measurement was performed. The compound D1 corresponds to the second material (thermally active delayed fluorescent material) according to this embodiment.

In the emission spectrum of the co-deposited film containing the reference compound H1 and the compound D1 of the thin film sample A, the emission intensity was larger on the longer wavelength side than the peak wavelength of the emission spectrum of the original organic molecule (compound D1). Such an increase in the emission intensity on the long wavelength side is presumed to be caused by an exciplex being formed by physically joining the organic molecules of the matrix material and the doping material. This is because an exciplex is generally formed by physically joining different organic molecules to each other, and the emission level is formed on the longer wavelength side of the exciplex than the organic molecule of the doping material.
Further, the triplet energy of the reference compound H1 is higher than the triplet energy of the compound D1. From this, the emission spectrum observed in the transient PL is considered to be derived from the compound D1 having a triplet energy lower than that of the reference compound H1, or from a newly formed exciplex. Further, it has been found that a compound having a CN group and a high acceptor property such as compound D1 cannot retain excitons even if a matrix material is selected only for the reason of high triplet energy.

The behavior of delayed fluorescence can also be analyzed based on the decay curve obtained from the transient PL measurement. Transient PL is a technique for measuring the decay behavior (transient characteristics) of PL emission after irradiating a sample with a pulsed laser and exciting it and stopping the irradiation. PL emission in the TADF material is classified into a light emission component from a singlet exciton generated by the first PL excitation and a light emission component from a singlet exciton generated via a triplet exciton. The lifetime of singlet excitons generated by the first PL excitation is on the order of nanoseconds and is very short. Therefore, light emitted from the singlet excitons is rapidly attenuated after irradiation with the pulse laser.
On the other hand, delayed fluorescence is gradually attenuated due to light emission from singlet excitons generated via a long-lived triplet exciton. Thus, there is a large time difference between the light emission from the singlet exciton generated by the first PL excitation and the light emission from the singlet exciton generated via the triplet exciton. Therefore, the emission intensity derived from delayed fluorescence can be obtained.

  Here, the attenuation curve was analyzed using the thin film sample A and the thin film sample B described above. The thin film sample B was prepared as described above using the following reference compound H2 as a matrix material and the compound D1 as a doping material.

FIG. 3 shows attenuation curves obtained from the transient PL measured for the thin film sample A and the thin film sample B.
Both of the thin film samples A and B have a thin film in which the compound D1 which is a delayed fluorescent compound is used as a doping material and the compound D1 is dispersed in the matrix material. Therefore, it was considered that the transient PL of the co-deposited film of these thin film samples was observed as a single exponential function.
However, for the transient PL of the co-deposited film of the thin film sample A, as shown in FIG. 3, the curve portion derived from delayed fluorescence of the decay curve is observed as a luminescent component by a non-single exponential function. This is considered to be observed as a non-single exponential function because of the exchange of energy transfer between the emission level of the exciplex and the emission level of the compound D1.
On the other hand, for the transient PL of the co-deposited film of the thin film sample B, as shown in FIG. 3, the curve portion derived from delayed fluorescence of the decay curve is observed as a luminescent component by a single exponential function. Therefore, it is speculated that the reference compound H2 and the compound D1 are a combination that hardly forms an exciplex.

  From the above study, it was confirmed that the matrix material confined the triplet energy of the doping material by observing the transient PL emission spectrum of the co-deposited film and selecting the matrix material and the doping material in an appropriate combination. It was. On the other hand, if an unsuitable combination is selected, even when the triplet energy of the matrix material is large, the exciplex formation of the matrix material and the doping material may prevent the exciton triplet energy from being effectively confined. It could be confirmed. If the triplet energy confinement is weak, it is observed as a non-single exponential function in the decay curve, and the heat deactivation mode due to the formation of the exciplex increases, leading to a decrease in luminous efficiency. As described above, since the exciplex appears on the long wavelength side of the transient PL emission spectrum, the exciplex is considered to have a triplet energy lower than that of the original molecule. That is, it can be predicted that the energy is transferred to an exciplex state having a low triplet energy, and that the light emission efficiency is lowered due to the non-light emission mode.

From the examination of the transient PL measurement described above, the first material and the second material are in contact with each other at the interface between the barrier layer and the light emitting layer, so that it is difficult to form an exciplex. The combination with other materials was found to be important.
It is important that the second material and the first material according to the present embodiment are selected and combined so that it is difficult to form an exciplex. Exciplex formation can be confirmed by transient PL measurement of the co-deposited film as described above.

・ Relationship of ionization potential Generally, a material with a large ionization potential is called an acceptor molecule, and a material with a low ionization potential is called a donor molecule. It is thought that an exciplex is likely to occur when an acceptor molecule and a donor molecule are adjacent. In particular, the thermally activated delayed fluorescent material according to this embodiment has a CN group that has strong acceptor properties. Therefore, it is considered that a thermally activated delayed fluorescent material and an amine-based material common as a hole transport material of an organic EL element can easily form an exciplex.
In the case of the combination of the reference compound H1 and the compound D1 which is a thermally activated delayed fluorescent material, the ionization potential of the compound D1 as the doping material is larger than the ionization potential of the reference compound H1 as the matrix material. In this case, an exciplex is formed with a high probability. On the other hand, in the case of the combination of the reference compound H2 and the compound D1, since the ionization potential of the reference compound H2 is larger than the ionization potential of the compound D1, the formation of an exciplex can be efficiently prevented. Both the reference compound H1 and the reference compound H2 are compounds having a dicarbazole skeleton, but it is generally known that the donor performance varies depending on how the carbazole skeleton is bonded. In the case of this reference example, it is known that the reference compound H1 has a lower ionization potential and stronger donor performance than the reference compound H2.

Therefore, in the organic EL element 1 of the present embodiment, the ionization potential of the second material contained in the second organic layer 6 is higher than the ionization potential IP _B of the first material contained in the first organic layer 5. by combining as towards the potential IP _T is reduced, it can suppress the formation of an exciplex.

In this embodiment, when a second material having a cyano group is used for the second organic layer 6, an exciplex is formed when the first material contained in the first organic layer 5 is an amine compound. Easy to do. The second material having a cyano group has a large ionization potential, and the amine compound has a small ionization potential. Therefore, an exciplex is likely to be formed at the interface between the second organic layer 6 and the first organic layer 5. Conceivable.
Therefore, for example, a second material having a partial structure represented by the general formula (1) and a partial structure represented by the general formula (2) in one molecule is used for the second organic layer 6. In that case, it is preferable to use a non-amine compound as the first material contained in the first organic layer 5.

  The ionization potential can be measured using a photoelectron spectrometer in the atmosphere. Specifically, the measurement was performed by irradiating the material with light and measuring the amount of electrons generated by charge separation at that time. Examples of the measuring device include a photoelectron spectrometer (device name: AC-3) manufactured by Riken Keiki Co., Ltd.

In the organic EL element 1 of the present embodiment, the first material contained in the first organic layer 5 and the second material contained in the second organic layer 6 have the relationship of the above mathematical formula (Equation 1). Satisfies. Furthermore, the concentration of the second material in the second organic layer 6 is increased to 12% by mass or more.
As a result, it is difficult for the second material and the first material to form an exciplex at the interface between the second organic layer 6 and the first organic layer 5, and light is emitted even when the concentration of the second material is increased. Efficiency is less likely to decrease.
Furthermore, since the concentration of the second material in the second organic layer 6 is increased, the driving voltage of the element is lowered. This is presumably because ΔST of the second material is small, and a compound having a small ΔST is excellent in carrier transportability, and is therefore responsible for the carrier transport function in the second organic layer 6.
Therefore, the organic EL element 1 has a lower driving voltage and improved luminous efficiency than the conventional fluorescent light emitting organic EL element.
In the organic EL device described in Non-Patent Document 1, in order to confine triplet excitons in the light emitting layer, TrisPCz having a large triplet energy is used for the hole transport layer adjacent to the anode side of the light emitting layer. Yes. However, since the ionization potential of TrisPCz is smaller than that of the thermally activated delayed fluorescent material (4CzIPN), an exciplex is easily formed at the interface between the light emitting layer and the hole transport layer.

  Conventional fluorescent light-emitting organic EL elements generally have a problem of concentration quenching. For this reason, a doping system is employed for the fluorescent organic EL element. That is, a dopant material is doped and dispersed in a host material that mainly forms a light emitting layer. Such a doping system prevents the exciplex formation between the dopant materials, thereby preventing a decrease in luminous efficiency.

・ ΔST
In the organic EL device of this embodiment, the singlet energy S (M2) of the thermally activated delayed fluorescent material as the second material and the energy gap T _77K (M2) at 77 [K] of the thermally activated delayed fluorescent material It is preferable that the difference ΔST (M2) satisfies the following mathematical formula (Formula 3).
ΔST (M2) = S (M2) −T _77K (M2) <0.3 [eV] (Expression 3)
In addition, ΔST (M2) is preferably less than 0.2 [eV].

Here, ΔST will be described. When a compound having a small energy difference (ΔST) between singlet energy S and triplet energy T is used, the organic EL element emits light with high efficiency in a high current density region. The above ΔST (M2) represents ΔST of the thermally activated delayed fluorescent material.
In order to reduce ΔST that is equivalent to the difference between the singlet energy S and the triplet energy T, quantum exchange is realized by a small exchange interaction between the singlet energy S and the triplet energy T. The physical details of the relationship between ΔST and exchange interaction are described in, for example, the following Reference 1 and Reference 2.
Reference 1: Chiyaya Adachi et al., Organic EL Discussion Session 10th Annual Meeting Proceedings, S2-5, p11-12
Reference 2: Katsumi Tokumaru, Organic Photochemical Reaction Theory, Tokyo Kagaku Doujin Publishing, (1973)
Such a material can be synthesized by molecular design by quantum calculation. Specifically, it is a compound localized so as not to overlap the LUMO and HOMO electron orbitals.
An example of a compound having a small ΔST used for the thermally activated delayed fluorescent material of the present embodiment is a compound in which a donor element and an acceptor element are combined in the molecule, and further has electrochemical stability (redox stability). In view of this, compounds having ΔST of 0 eV or more and less than 0.3 eV can be mentioned.
Further, a more preferable compound is a compound that forms an aggregate in which dipoles formed in an excited state of a molecule interact with each other and exchange interaction energy becomes small. According to the study by the present inventors, such a compound has approximately the same dipole direction, and ΔST can be further reduced by molecular interaction. In such a case, ΔST can be extremely small, from 0 eV to 0.2 eV.

-TADF mechanism As described above, when ΔST (M2) of the thermally activated delayed fluorescent material is small, the singlet level of the thermally activated delayed fluorescent material is changed from the triplet level of the thermally activated delayed fluorescent material by the externally applied thermal energy. It is easy for the inverse intersystem crossing to occur. An energy state conversion mechanism in which the excited triplet state of the electrically excited exciton inside the organic EL element is spin-exchanged to the excited singlet state by crossing between inverse terms is called a TADF mechanism.
In the organic EL device of the present embodiment, it is preferable to use a compound having a small ΔST (M2) as the thermally active delayed fluorescent material, and the thermal activated delay from the triplet level of the thermally activated delayed fluorescent material by the externally applied thermal energy. Reverse intersystem crossing to the singlet level of the fluorescent material is likely to occur.
FIG. 4 shows an example of the energy level relationship between the thermally activated delayed fluorescent material as the second material in the light emitting layer and the third material. In FIG. 4, S0 represents the ground state, S1 _H represents the lowest excited singlet state of the third material, T1 _H represents the lowest excited triplet state of the third material, and S1 _D represents The lowest excited singlet state of the thermally activated delayed fluorescent material is represented, T1 _D represents the lowest excited triplet state of the thermally activated delayed fluorescent material, and the dashed arrow represents the energy transfer between each excited state. As shown in FIG. 4, by using a material having a small ΔST (M2) as the thermally activated delayed fluorescent material, the lowest excitation of the thermally activated delayed fluorescent material due to Dexter movement from the lowest excited triplet state T1 _{H of} the third material. Energy transfer to singlet state S1 _D or lowest excited triplet state T1 _D. Further, the lowest excited triplet state T1 _D of the thermally activated delayed fluorescent material can cross back to the lowest excited singlet state S1 _D by thermal energy. As a result, the lowest excited singlet of the thermally activated delayed fluorescent material can be crossed. Fluorescence emission from the term state S1 _D can be observed. It is believed that the internal efficiency can theoretically be increased to 100% also by utilizing delayed fluorescence due to this TADF mechanism.
The present invention is not limited to the relationship between the energy levels of the thermally activated delayed fluorescent material and the third material as shown in FIG. For example, by using a thermally active delayed fluorescent material having a small ΔST (M2), the thermal excitation is caused to easily cause reverse intersystem crossing from the lowest excited triplet state T1 _D to the lowest excited singlet state S1 _D by thermal energy. The light emitting layer may be configured to transfer energy from the lowest excited singlet state S1 _D of the material to the lowest excited singlet state S1 _{H of} the third material.

-Relationship between triplet energy and energy gap at 77 [K] Here, the relationship between triplet energy and energy gap at 77 [K] will be described. In the present embodiment, the energy gap at 77 [K] is different from the normally defined triplet energy.
The triplet energy is measured as follows. First, a compound to be measured is deposited on a quartz substrate to prepare a sample. With respect to this sample, a phosphorescence spectrum (vertical axis: phosphorescence emission intensity, horizontal axis: wavelength) is measured at a low temperature (77 [K]), and a tangent line is drawn with respect to the rising edge on the short wavelength side of the phosphorescence spectrum, Based on the wavelength value at the intersection of the tangent and the horizontal axis, triplet energy is calculated from a predetermined conversion formula.
Here, the compound used in this embodiment is preferably a compound having a small ΔST. When ΔST is small, intersystem crossing and reverse intersystem crossing easily occur even in a low temperature (77 [K]) state, and an excited singlet state and an excited triplet state are mixed. As a result, the spectrum measured in the same manner as described above includes light emission from both the excited singlet state and the excited triplet state, and it is difficult to distinguish from which state the light is emitted. However, basically, the triplet energy value is considered to be dominant.
Therefore, in the present embodiment, the normal triplet energy T and the measurement method are the same, but in order to distinguish the difference in the strict meaning, the value measured as follows is referred to as an energy gap T _77K. . A compound to be measured is deposited on a quartz substrate with a film thickness of 100 nm to prepare a sample. With respect to this sample, a phosphorescence spectrum (vertical axis: phosphorescence emission intensity, horizontal axis: wavelength) is measured at a low temperature (77 [K]), and a tangent line is drawn with respect to the rising edge on the short wavelength side of the phosphorescence spectrum, Based on the wavelength value λ _edge [nm] at the intersection of the tangent and the horizontal axis, the energy amount calculated from the following conversion formula 1 is defined as an energy gap T _77K .
Conversion formula 1: T _77K [eV] = 1239.85 / λ _edge
The tangent to the rising edge on the short wavelength side of the phosphorescence spectrum is drawn as follows. When moving on the spectrum curve from the short wavelength side of the phosphorescence spectrum to the maximum value on the shortest wavelength side among the maximum values of the spectrum, tangents at each point on the curve are considered toward the long wavelength side. The slope of this tangent line increases as the curve rises (that is, as the vertical axis increases). A tangent drawn at a point where the value of the slope takes a maximum value (that is, a tangent at the inflection point) is a tangent to the rising edge of the phosphorescence spectrum on the short wavelength side.
Note that the maximum point having a peak intensity of 15% or less of the maximum peak intensity of the spectrum is not included in the above-mentioned maximum value on the shortest wavelength side, and has the maximum slope value closest to the maximum value on the shortest wavelength side. The tangent drawn at the point where the value is taken is taken as the tangent to the rise on the short wavelength side of the phosphorescence spectrum.
For measurement of phosphorescence, an F-4500 spectrofluorometer main body manufactured by Hitachi High-Technology Co., Ltd. can be used. Note that the measurement device is not limited to this, and the measurement may be performed by combining a cooling device and a cryogenic container, an excitation light source, and a light receiving device.

・ Singlet energy S
The singlet energy S is measured as follows.
A sample to be measured is deposited on a quartz substrate with a film thickness of 100 nm to prepare a sample, and the emission spectrum (vertical axis: emission intensity, horizontal axis: wavelength) of this sample is measured at room temperature (300 K). . A tangent line is drawn with respect to the rise of the emission spectrum on the short wavelength side, and is calculated from the following conversion formula 2 based on the wavelength value λ _edge [nm] at the intersection of the tangent line and the horizontal axis.
Conversion formula 2: S [eV] = 1239.85 / λ _edge
The absorption spectrum is measured with a spectrophotometer. For example, a Hitachi spectrophotometer (device name: U3310) or the like can be used.

A tangent to the rising edge of the emission spectrum on the short wavelength side is drawn as follows. When moving on the spectrum curve from the short wavelength side of the emission spectrum to the maximum value on the shortest wavelength side of the maximum value of the spectrum, tangents at each point on the curve are considered toward the long wavelength side. The slope of this tangent line increases as the curve rises (that is, as the vertical axis increases). The tangent drawn at the point where the value of the slope takes the maximum value (that is, the tangent at the inflection point) is the tangent to the rising edge of the emission spectrum on the short wavelength side.
Note that the maximum point having a peak intensity of 15% or less of the maximum peak intensity of the spectrum is not included in the above-mentioned maximum value on the shortest wavelength side, and has the maximum slope value closest to the maximum value on the shortest wavelength side. The tangent drawn at the point where the value is taken is taken as the tangent to the rising edge of the emission spectrum on the short wavelength side.

In the present embodiment, the difference between the singlet energy S and the energy gap T _77K is defined as ΔST.

(substrate)
The substrate is used as a support for the organic EL element. For example, glass, quartz, plastic, or the like can be used as the substrate. Further, a flexible substrate may be used. The flexible substrate is a substrate that can be bent (flexible), and examples thereof include plastic substrates made of polycarbonate, polyarylate, polyethersulfone, polypropylene, polyester, polyvinyl fluoride, and polyvinyl chloride. . Moreover, an inorganic vapor deposition film can also be used.

(anode)
For the anode formed on the substrate, it is preferable to use a metal, an alloy, an electrically conductive compound, a mixture thereof, or the like having a high work function (specifically, 4.0 eV or more). Specifically, for example, indium oxide-tin oxide (ITO): indium oxide-tin oxide containing silicon or silicon oxide, indium oxide-zinc oxide, tungsten oxide, and indium oxide containing zinc oxide And graphene. In addition, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium ( Pd), titanium (Ti), or a metal material nitride (for example, titanium nitride).
These materials are usually formed by sputtering. For example, indium oxide-zinc oxide can be formed by a sputtering method by using a target in which 1% by mass to 10% by mass of zinc oxide is added to indium oxide. For example, indium oxide containing tungsten oxide and zinc oxide contains 0.5% by mass to 5% by mass of tungsten oxide and 0.1% by mass to 1% by mass of zinc oxide with respect to indium oxide. By using a target, it can be formed by a sputtering method. In addition, you may produce by the vacuum evaporation method, the apply | coating method, the inkjet method, a spin coat method, etc.
Of the EL layers formed on the anode, the hole injection layer formed in contact with the anode is formed using a composite material that facilitates hole injection regardless of the work function of the anode. Any material that can be used as an electrode material (for example, a metal, an alloy, an electrically conductive compound, and a mixture thereof, and other elements belonging to Group 1 or Group 2 of the periodic table) can be used.
An element belonging to Group 1 or Group 2 of the periodic table, which is a material having a low work function, that is, an alkali metal such as lithium (Li) or cesium (Cs), and magnesium (Mg), calcium (Ca), or strontium Alkaline earth metals such as (Sr), and alloys containing these (eg, MgAg, AlLi), rare earth metals such as europium (Eu), ytterbium (Yb), and alloys containing these can also be used. Note that when an anode is formed using an alkali metal, an alkaline earth metal, and an alloy containing these, a vacuum evaporation method or a sputtering method can be used. Furthermore, when using a silver paste etc., the apply | coating method, the inkjet method, etc. can be used.

(cathode)
It is preferable to use a metal, an alloy, an electrically conductive compound, a mixture thereof, or the like having a low work function (specifically, 3.8 eV or less) for the cathode. Specific examples of such cathode materials include elements belonging to Group 1 or Group 2 of the periodic table of elements, that is, alkali metals such as lithium (Li) and cesium (Cs), and magnesium (Mg) and calcium (Ca ), Alkaline earth metals such as strontium (Sr), and alloys containing these (for example, rare earth metals such as MgAg, AlLi), europium (Eu), ytterbium (Yb), and alloys containing these.
Note that in the case where the cathode is formed using an alkali metal, an alkaline earth metal, or an alloy containing these, a vacuum evaporation method or a sputtering method can be used. Moreover, when using a silver paste etc., the apply | coating method, the inkjet method, etc. can be used.
By providing an electron injection layer, a cathode is formed using various conductive materials such as indium oxide-tin oxide containing Al, Ag, ITO, graphene, silicon, or silicon oxide regardless of the work function. can do. These conductive materials can be formed by a sputtering method, an inkjet method, a spin coating method, or the like.

(Hole injection layer)
The hole injection layer is a layer containing a substance having a high hole injection property. Substances with high hole injection properties include molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, Tungsten oxide, manganese oxide, or the like can be used.
As a substance having a high hole injection property, 4,4 ′, 4 ″ -tris (N, N-diphenylamino) triphenylamine (abbreviation: TDATA), 4,4 ′, which is a low molecular organic compound, is used. , 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA), 4,4′-bis [N- (4-diphenylaminophenyl) -N-phenyl Amino] biphenyl (abbreviation: DPAB), 4,4′-bis (N- {4- [N ′-(3-methylphenyl) -N′-phenylamino] phenyl} -N-phenylamino) biphenyl (abbreviation: DNTPD), 1,3,5-tris [N- (4-diphenylaminophenyl) -N-phenylamino] benzene (abbreviation: DPA3B), 3- [N- (9-phenylcarbazol-3-yl) -N -F Enylamino] -9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis [N- (9-phenylcarbazol-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA2), 3- An aromatic amine compound such as [N- (1-naphthyl) -N- (9-phenylcarbazol-3-yl) amino] -9-phenylcarbazole (abbreviation: PCzPCN1) can also be used.
As the substance having a high hole injecting property, a high molecular compound (an oligomer, a dendrimer, a polymer, or the like) can also be used. For example, poly (N-vinylcarbazole) (abbreviation: PVK), poly (4-vinyltriphenylamine) (abbreviation: PVTPA), poly [N- (4- {N ′-[4- (4-diphenylamino)] Phenyl] phenyl-N′-phenylamino} phenyl) methacrylamide] (abbreviation: PTPDMA), poly [N, N′-bis (4-butylphenyl) -N, N′-bis (phenyl) benzidine] (abbreviation: Polymer compounds such as Poly-TPD). In addition, a polymer compound to which an acid such as poly (3,4-ethylenedioxythiophene) / poly (styrenesulfonic acid) (PEDOT / PSS), polyaniline / poly (styrenesulfonic acid) (PAni / PSS) is added is used. You can also.

(Hole transport layer)
The hole transport layer is a layer containing a substance having a high hole transport property. An aromatic amine compound, a carbazole derivative, an anthracene derivative, or the like can be used for the hole transport layer. Specifically, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB) or N, N′-bis (3-methylphenyl) -N, N′— Diphenyl- [1,1′-biphenyl] -4,4′-diamine (abbreviation: TPD), 4-phenyl-4 ′-(9-phenylfluoren-9-yl) triphenylamine (abbreviation: BAFLP), 4 , 4′-bis [N- (9,9-dimethylfluoren-2-yl) -N-phenylamino] biphenyl (abbreviation: DFLDPBi), 4,4 ′, 4 ″ -tris (N, N-diphenylamino) ) Triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA), 4,4′-bis [N- (Spiro-9,9'-Biff Oren-2-yl) -N- phenylamino] biphenyl (abbreviation: BSPB) can be used aromatic amine compounds such as. The substances described here are mainly substances having a hole mobility of 10 ⁻⁶ cm ² / Vs or higher.
For the hole transport layer, a carbazole derivative such as CBP, CzPA, or PCzPA, or an anthracene derivative such as t-BuDNA, DNA, or DPAnth may be used. A high molecular compound such as poly (N-vinylcarbazole) (abbreviation: PVK) or poly (4-vinyltriphenylamine) (abbreviation: PVTPA) can also be used.
Note that other than these substances, any substance that has a property of transporting more holes than electrons may be used. Note that the layer containing a substance having a high hole-transport property is not limited to a single layer, and two or more layers containing the above substances may be stacked.

(Electron transport layer)
The electron transport layer is a layer containing a substance having a high electron transport property. For the electron transport layer, 1) metal complexes such as aluminum complexes, beryllium complexes and zinc complexes, 2) heteroaromatic compounds such as imidazole derivatives, benzimidazole derivatives, azine derivatives, carbazole derivatives and phenanthroline derivatives, and 3) polymer compounds Can be used. Specifically, as a low-molecular organic compound, Alq, tris (4-methyl-8-quinolinolato) aluminum (abbreviation: Almq ₃ ), bis (10-hydroxybenzo [h] quinolinato) beryllium (abbreviation: BeBq ₂ ), A metal complex such as BAlq, Znq, ZnPBO, ZnBTZ, or the like can be used. In addition to metal complexes, 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis [5- (Pert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 3- (4-tert-butylphenyl) -4-phenyl-5- (4- Biphenylyl) -1,2,4-triazole (abbreviation: TAZ), 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenylyl) -1,2,4- Triazole (abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: BPhen), bathocuproin (abbreviation: BCP), 4,4′-bis (5-methylbenzoxazol-2-yl) stilbene (abbreviation: B) Heteroaromatic compounds such as zOs) can also be used. The substances mentioned here are mainly substances having an electron mobility of 10 ⁻⁶ cm ² / Vs or higher. Note that any substance other than the above substances may be used for the electron-transport layer as long as the substance has a higher electron-transport property than the hole-transport property. Further, the electron-transport layer is not limited to a single layer, and two or more layers including the above substances may be stacked.
Moreover, a high molecular compound can also be used for an electron carrying layer. For example, poly [(9,9-dihexylfluorene-2,7-diyl) -co- (pyridine-3,5-diyl)] (abbreviation: PF-Py), poly [(9,9-dioctylfluorene-2) , 7-diyl) -co- (2,2′-bipyridine-6,6′-diyl)] (abbreviation: PF-BPy) and the like can be used.

(Electron injection layer)
The electron injection layer is a layer containing a substance having a high electron injection property. For the electron injection layer, lithium (Li), cesium (Cs), calcium (Ca), lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF ₂ ), lithium oxide (LiOx), etc. An alkali metal, an alkaline earth metal, or a compound thereof can be used. In addition, a substance in which an alkali metal, an alkaline earth metal, or a compound thereof is contained in a substance having an electron transporting property, specifically, a substance in which magnesium (Mg) is contained in Alq may be used. In this case, electron injection from the cathode can be performed more efficiently.
Alternatively, a composite material obtained by mixing an organic compound and an electron donor (donor) may be used for the electron injection layer. Such a composite material is excellent in electron injecting property and electron transporting property because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material excellent in transporting the generated electrons. Specifically, for example, a substance (metal complex, heteroaromatic compound, or the like) constituting the electron transport layer described above is used. be able to. The electron donor may be any substance that exhibits an electron donating property to the organic compound. Specifically, alkali metals, alkaline earth metals, and rare earth metals are preferable, and lithium, cesium, magnesium, calcium, erbium, ytterbium, and the like can be given. Alkali metal oxides and alkaline earth metal oxides are preferable, and lithium oxide, calcium oxide, barium oxide, and the like can be given. A Lewis base such as magnesium oxide can also be used. Alternatively, an organic compound such as tetrathiafulvalene (abbreviation: TTF) can be used.

(Layer formation method)
The method for forming each layer of the organic EL element of the present embodiment is not limited except as specifically mentioned above, but a dry film forming method such as a vacuum evaporation method, a sputtering method, a plasma method, an ion plating method, a spin method, Known methods such as a coating method, a dipping method, a flow coating method, and a wet film forming method such as an ink jet method can be employed.

(Film thickness)
The film thickness of each organic layer of the organic EL element of the present embodiment is not limited except as specifically mentioned above. Generally, if the film thickness is too thin, defects such as pinholes are likely to occur, and conversely, if it is too thick, it is high. Since an applied voltage is required and the efficiency is deteriorated, the range of several nm to 1 μm is usually preferable.

In this specification, the number of ring-forming carbon atoms constitutes the ring itself of a compound having a structure in which atoms are bonded cyclically (for example, a monocyclic compound, a condensed ring compound, a bridged compound, a carbocyclic compound, or a heterocyclic compound). Represents the number of carbon atoms in the atom. When the ring is substituted with a substituent, the carbon contained in the substituent is not included in the number of ring-forming carbons. The “ring-forming carbon number” described below is the same unless otherwise specified. For example, the benzene ring has 6 ring carbon atoms, the naphthalene ring has 10 ring carbon atoms, the pyridinyl group has 5 ring carbon atoms, and the furanyl group has 4 ring carbon atoms. Further, when an alkyl group is substituted as a substituent on the benzene ring or naphthalene ring, the carbon number of the alkyl group is not included in the number of ring-forming carbons. In addition, when a fluorene ring is bonded to the fluorene ring as a substituent (including a spirobifluorene ring), the number of carbon atoms of the fluorene ring as a substituent is not included in the number of ring-forming carbon atoms.
The number of ring-forming atoms represents the number of atoms constituting the ring itself of a compound having a structure in which atoms are bonded in a ring (for example, a monocyclic compound, a condensed ring compound, a bridged compound, a carbocyclic compound, or a heterocyclic compound). . An atom that does not constitute a ring (for example, a hydrogen atom that terminates the dangling bond of an atom that constitutes a ring) or an atom contained in a substituent when the ring is substituted by a substituent is included in the number of ring-forming atoms Absent. The “number of ring-forming atoms” described below is the same unless otherwise specified. For example, the pyridine ring has 6 ring atoms, the quinazoline ring has 10 ring atoms, and the furan ring has 5 ring atoms. A hydrogen atom bonded to a carbon atom of a pyridine ring or a quinazoline ring or an atom constituting a substituent is not included in the number of ring-forming atoms. Further, when, for example, a fluorene ring is bonded to the fluorene ring as a substituent (including a spirobifluorene ring), the number of atoms of the fluorene ring as a substituent is not included in the number of ring-forming atoms.
Next, each substituent described in the general formula will be described.

Examples of the aryl group having 6 to 30 ring carbon atoms (sometimes referred to as an aromatic hydrocarbon group) in the present embodiment include a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. , Fluorenyl group, pyrenyl group, chrysenyl group, fluoranthenyl group, benzo [a] anthryl group, benzo [c] phenanthryl group, triphenylenyl group, benzo [k] fluoranthenyl group, benzo [g] chrysenyl group, benzo [g b] A triphenylenyl group, a picenyl group, a perylenyl group, and the like.
As an aryl group in this embodiment, it is preferable that ring formation carbon number is 6-20, More preferably, it is still more preferable that it is 6-12. Among the aryl groups, a phenyl group, a biphenyl group, a naphthyl group, a phenanthryl group, a terphenyl group, and a fluorenyl group are particularly preferable. For the 1-fluorenyl group, 2-fluorenyl group, 3-fluorenyl group and 4-fluorenyl group, the substituted or unsubstituted alkyl group having 1 to 30 carbon atoms in the present embodiment described later on the 9-position carbon atom, or It is preferable that the substituted or unsubstituted aryl group having 6 to 18 ring carbon atoms is substituted.

In the present embodiment, a heterocyclic group having 5 to 30 ring atoms (sometimes referred to as a heteroaryl group, a heteroaromatic ring group, or an aromatic heterocyclic group) has nitrogen, sulfur, oxygen as a heteroatom. Preferably, it contains at least one atom selected from the group consisting of silicon, selenium atom, and germanium atom, and more preferably contains at least one atom selected from the group consisting of nitrogen, sulfur, and oxygen preferable.
Examples of the heterocyclic group having 5 to 30 ring atoms in this embodiment include a pyridyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolyl group, an isoquinolinyl group, a naphthyridinyl group, a phthalazinyl group, a quinoxalinyl group, Quinazolinyl group, phenanthridinyl group, acridinyl group, phenanthrolinyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, triazolyl group, tetrazolyl group, indolyl group, benzimidazolyl group, indazolyl group, imidazolpyridinyl group, benz Triazolyl, carbazolyl, furyl, thienyl, oxazolyl, thiazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, thiadiazolyl, benzofuranyl, benzothiophenyl, benzoxazolyl Group, benzothiazolyl group, benzisoxazolyl group, benzoisothiazolyl group, benzoxiadiazolyl group, benzothiadiazolyl group, dibenzofuranyl group, dibenzothiophenyl group, piperidinyl group, pyrrolidinyl group, piperazinyl group, morpholyl Group, phenazinyl group, phenothiazinyl group, phenoxazinyl group and the like.
The number of ring-forming atoms of the heterocyclic group in this embodiment is preferably 5-20, and more preferably 5-14. Among the above heterocyclic groups, 1-dibenzofuranyl group, 2-dibenzofuranyl group, 3-dibenzofuranyl group, 4-dibenzofuranyl group, 1-dibenzothiophenyl group, 2-dibenzothiophenyl group, 3- A dibenzothiophenyl group, 4-dibenzothiophenyl group, 1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, and 9-carbazolyl group are particularly preferable. With respect to the 1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group and 4-carbazolyl group, the substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms in the present embodiment or substitution on the 9th-position nitrogen atom Alternatively, an unsubstituted heterocyclic group having 5 to 30 ring atoms is preferably substituted.

  In this embodiment, the heterocyclic group may be a group derived from a partial structure represented by the following general formulas (XY-1) to (XY-18), for example.

  In the general formulas (XY-1) to (XY-18), X and Y are each independently a hetero atom, preferably an oxygen atom, a sulfur atom, a selenium atom, a silicon atom, or a germanium atom. . The partial structures represented by the general formulas (XY-1) to (XY-18) have a bond at an arbitrary position to be a heterocyclic group, and this heterocyclic group has a substituent. Also good.

  In the present embodiment, the substituted or unsubstituted carbazolyl group may include, for example, a group obtained by further condensing a ring with a carbazole ring represented by the following formula. Such a group may also have a substituent. Also, the position of the joint can be changed as appropriate.

In the present embodiment, the alkyl group having 1 to 30 carbon atoms may be linear, branched or cyclic. Examples of the linear or branched alkyl group include a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, neopentyl group, amyl group, isoamyl group, 1-methylpentyl group, 2-methylpentyl group, 1-pentylhexyl group, 1-butylpentyl group, 1- A heptyloctyl group and a 3-methylpentyl group.
The linear or branched alkyl group in the present embodiment preferably has 1 to 10 carbon atoms, and more preferably 1 to 6 carbon atoms. Among the linear or branched alkyl groups, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexyl group , An amyl group, an isoamyl group, and a neopentyl group are particularly preferable.
Examples of the cycloalkyl group in this embodiment include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a 4-methylcyclohexyl group, an adamantyl group, and a norbornyl group. The ring-forming carbon number of the cycloalkyl group is preferably 3 to 10, and more preferably 5 to 8. Among the cycloalkyl groups, a cyclopentyl group and a cyclohexyl group are particularly preferable.
Examples of the halogenated alkyl group in which the alkyl group is substituted with a halogen atom include those in which the alkyl group having 1 to 30 carbon atoms is substituted with one or more halogen groups. Specific examples include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a fluoroethyl group, a trifluoromethylmethyl group, a trifluoroethyl group, and a pentafluoroethyl group.

  Examples of the alkylsilyl group having 3 to 30 carbon atoms in the present embodiment include a trialkylsilyl group having an alkyl group exemplified as the alkyl group having 1 to 30 carbon atoms, specifically, a trimethylsilyl group and a triethylsilyl group. , Tri-n-butylsilyl group, tri-n-octylsilyl group, triisobutylsilyl group, dimethylethylsilyl group, dimethylisopropylsilyl group, dimethyl-n-propylsilyl group, dimethyl-n-butylsilyl group, dimethyl-t- Examples thereof include a butylsilyl group, a diethylisopropylsilyl group, a vinyldimethylsilyl group, a propyldimethylsilyl group, and a triisopropylsilyl group. The three alkyl groups in the trialkylsilyl group may be the same or different.

Examples of the arylsilyl group having 6 to 30 ring carbon atoms in the present embodiment include a dialkylarylsilyl group, an alkyldiarylsilyl group, and a triarylsilyl group.
The dialkylarylsilyl group includes, for example, a dialkylarylsilyl group having two alkyl groups exemplified for the alkyl group having 1 to 30 carbon atoms and one aryl group having 6 to 30 ring carbon atoms. . The carbon number of the dialkylarylsilyl group is preferably 8-30.
Examples of the alkyldiarylsilyl group include an alkyldiarylsilyl group having one alkyl group exemplified for the alkyl group having 1 to 30 carbon atoms and two aryl groups having 6 to 30 ring carbon atoms. . The alkyldiarylsilyl group preferably has 13 to 30 carbon atoms.
Examples of the triarylsilyl group include a triarylsilyl group having three aryl groups having 6 to 30 ring carbon atoms. The carbon number of the triarylsilyl group is preferably 18-30.

Alkoxy group having 1 to 30 carbon atoms in the present embodiment is represented as -OZ _1. Examples of _{Z 1,} include alkyl groups of 1 to 30 carbon atoms. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, and a hexyloxy group.
Examples of the halogenated alkoxy group in which the alkoxy group is substituted with a halogen atom include those in which the C 1-30 alkoxy group is substituted with one or more halogen groups.

Aryloxy group ring forming C6-30 in this embodiment is expressed as -OZ _2. Examples of the Z ₂ include the aryl group having 6 to 30 ring carbon atoms. Examples of the aryloxy group include a phenoxy group.

Alkylamino group having 2 to 30 carbon atoms is represented as -NHR _V or -N _{(R V) 2,.} Examples of _{R V,} include alkyl groups of 1 to 30 carbon atoms.

The arylamino group having 6 to 60 ring carbon atoms is represented as —NHR _W or —N (R _W ) ₂ . Examples of R _W, and an aryl group the ring-forming C6-30.

Alkylthio group having 1 to 30 carbon atoms is represented as -SR _V. Examples of _{R V,} include alkyl groups of 1 to 30 carbon atoms.
Ring formation arylthio group having 6 to 30 carbon atoms is expressed as -SR _W. Examples of R _W, and an aryl group the ring-forming C6-30.

In the present specification, “ring-forming carbon” means a carbon atom constituting a saturated ring, an unsaturated ring, or an aromatic ring. “Ring-forming atom” means a carbon atom and a hetero atom constituting a hetero ring (including a saturated ring, an unsaturated ring, and an aromatic ring).
In the present specification, the hydrogen atom includes isotopes having different neutron numbers, that is, light hydrogen (Protium), deuterium (Deuterium), and tritium (Tritium).

In addition, examples of the substituent in this embodiment, such as a substituent in the case of “substituted or unsubstituted”, a substituent in ring structure A, and ring structure B, include the aryl group, heterocyclic group, alkyl group ( Linear or branched alkyl group, cycloalkyl group, haloalkyl group), alkylsilyl group, arylsilyl group, alkoxy group, aryloxy group, alkylamino group, arylamino group, alkylthio group, arylthio group, alkenyl group Groups, alkynyl groups, aralkyl groups, halogen atoms, cyano groups, hydroxyl groups, nitro groups, and carboxy groups.
Among the substituents mentioned here, an aryl group, a heterocyclic group, an alkyl group, a halogen atom, an alkylsilyl group, an arylsilyl group, and a cyano group are preferable. Are preferred.

  The alkenyl group is preferably an alkenyl group having 2 to 30 carbon atoms, which may be linear, branched or cyclic, for example, vinyl group, propenyl group, butenyl group, oleyl group, eicosapentaenyl group. , Docosahexaenyl group, styryl group, 2,2-diphenylvinyl group, 1,2,2-triphenylvinyl group, 2-phenyl-2-propenyl group, cyclopentadienyl group, cyclopentenyl group, cyclohexenyl group And cyclohexadienyl group.

  The alkynyl group is preferably an alkynyl group having 2 to 30 carbon atoms, and may be linear, branched or cyclic, and examples thereof include ethynyl, propynyl, 2-phenylethynyl and the like.

As the aralkyl group, an aralkyl group having 6 to 30 ring carbon atoms is preferable and represented by -Z ₃ -Z ₄ . Examples of Z ₃ include alkylene groups corresponding to the alkyl groups having 1 to 30 carbon atoms. Examples of this Z ₄ include the above aryl group having 6 to 30 ring carbon atoms. This aralkyl group is an aralkyl group having 7 to 30 carbon atoms (the aryl moiety is 6 to 30, preferably 6 to 20, more preferably 6 to 12), and the alkyl moiety is 1 to 30 carbon atoms (preferably 1 to 20, more preferably 1-10, still more preferably 1-6). Examples of the aralkyl group include benzyl group, 2-phenylpropan-2-yl group, 1-phenylethyl group, 2-phenylethyl group, 1-phenylisopropyl group, 2-phenylisopropyl group, and phenyl-t-butyl. Group, α-naphthylmethyl group, 1-α-naphthylethyl group, 2-α-naphthylethyl group, 1-α-naphthylisopropyl group, 2-α-naphthylisopropyl group, β-naphthylmethyl group, 1-β- Examples include naphthylethyl group, 2-β-naphthylethyl group, 1-β-naphthylisopropyl group, and 2-β-naphthylisopropyl group.

Examples of the halogen atom include fluorine, chlorine, bromine, iodine, and the like, preferably a fluorine atom.

In the present specification, a substituent in the case of “substituted or unsubstituted” may be further substituted with the above substituent. In the case of “substituted or unsubstituted”, a plurality of substituents may be bonded to each other to form a ring.
In addition, “unsubstituted” in the case of “substituted or unsubstituted” means that a hydrogen atom is bonded without being substituted with the above substituent.
In addition, “carbon number XX to YY” in the expression “substituted or unsubstituted ZZ group having XX to YY” represents the number of carbon atoms when the ZZ group is unsubstituted and substituted. The carbon number of the substituent in the case is not included. Here, “YY” is larger than “XX”, and “XX” and “YY” each mean an integer of 1 or more.
In the present embodiment, “atom number XX to YY” in the expression “a ZZ group having a substituted or unsubstituted atom number XX to YY” represents the number of atoms when the ZZ group is unsubstituted, In this case, the number of substituent atoms is not included. Here, “YY” is larger than “XX”, and “XX” and “YY” each mean an integer of 1 or more.
In the compound described below or a partial structure thereof, the case of “substituted or unsubstituted” is the same as described above.
In the present embodiment, examples of the aryl group and heteroaryl group in the linking group include a divalent or higher group obtained by removing one or more atoms from the monovalent group described above.
In the present embodiment, examples of the aromatic hydrocarbon ring and the heterocyclic ring include a ring structure derived from the above-described monovalent group.

[Second Embodiment]
The organic EL device according to the second embodiment basically has the same configuration as the organic EL device 1 according to the first embodiment, and the material contained in the second organic layer (light emitting layer) 6 is: A light emitting material having a partial structure represented by the general formula (1) and a partial structure represented by the general formula (2), wherein the light emitting material has an emission maximum peak wavelength of 510 nm or more, and the first organic The ionization potential IP _B of the first material contained in the layer (barrier layer) 5 is different from the ionization potential IP _E of the light emitting material in that the relationship of the following mathematical formula (Equation 2) is satisfied.

IP _B > IP _E (Expression 2)

  In the second embodiment, the same materials and compounds as those described in the first embodiment can be used unless otherwise specified.

In the organic EL element of the second embodiment, the first material included in the first organic layer 5 and the light-emitting material included in the second organic layer 6 satisfy the relationship of the mathematical formula (Equation 2). Yes. Further, the light emitting material in the second organic layer 6 has a partial structure represented by the general formula (1) and a partial structure represented by the general formula (2), and the light emission material has a maximum emission peak wavelength. It is 510 nm or more. The emission maximum peak wavelength can be obtained by photoluminescence spectrum measurement.
In such an organic EL element of the second embodiment, the luminescent material exhibits thermally activated delayed fluorescence and has a CN group, so that the ionization potential is increased. Therefore, when an amine compound having a small ionization potential is used for the first organic layer 5 adjacent to the second organic layer 6, an exciplex is easily formed. However, in the organic EL element of the present embodiment, the ionization potential of the light emitting material and the first material satisfies the relationship of the mathematical formula (Equation 2), so the interface between the second organic layer 6 and the first organic layer 5 In this case, it is difficult to form an exciplex.
Furthermore, since the luminescent material of this embodiment has the partial structure represented by the general formula (1) and the partial structure represented by the general formula (2), ΔST is small. Therefore, since the light emitting material is excellent in carrier transportability, it is considered that it becomes a carrier of the carrier transport function in the second organic layer 6.

When the organic EL element is used as a light emitting element that emits light in three primary colors of red, green, and blue, it is desired to optimize the element configuration in accordance with the respective emission colors of red, green, and blue. In the blue phosphorescent organic EL element, it is necessary to confine high excitation energy in the light emitting layer. Therefore, in order to realize a highly efficient blue phosphorescent organic EL element, it is necessary to provide an exciton barrier layer adjacent to the light emitting layer. This leads to a complicated organic EL element configuration and multilayer lamination, and at the same time, a higher driving voltage is required compared to the red element and the green element.
On the other hand, for organic EL elements that emit red or green light, the excitation energy of light emission is low, so that a wide range of general amine compounds can be applied to the hole transport layer adjacent to the light emitting layer. However, the light emitting material of this embodiment includes the partial structure represented by the general formula (1) and the partial structure represented by the general formula (2), and is a conventional organic EL element that emits light in red or green. As in the case of the above, if the first organic layer 5 is designed without being adjacent, an amine compound having a small ionization potential in the hole transport layer, and a thermally activated delayed fluorescent light emitting material in the light emitting layer, Thus, an exciplex is easily formed, resulting in a decrease in luminous efficiency.

  Therefore, in the present embodiment, the first material of the first organic layer 5 and the light emitting material of the second organic layer 6 are not used to confine high excitation energy but from the viewpoint of suppressing the formation of an exciplex. An organic EL element is configured in combination so as to satisfy the above-described conditions. As a result, the organic EL element of the present embodiment can improve the light emission efficiency and lower the drive voltage.

[Modification of Embodiment]
In addition, this invention is not limited to the above-mentioned embodiment, The change in the range which can achieve the objective of this invention, improvement, etc. are included in this invention.

The light emitting layer is not limited to one layer, and a plurality of light emitting layers may be stacked. When the organic EL element has a plurality of light emitting layers, it is sufficient that at least one light emitting layer and the barrier layer adjacent on the anode side of the light emitting layer satisfy the conditions described in the above embodiment. The layer may be a fluorescent light emitting layer or a phosphorescent light emitting layer.
In addition, when the organic EL element has a plurality of light emitting layers, these light emitting layers may be provided adjacent to each other, or a so-called tandem organic material in which a plurality of light emitting units are stacked via an intermediate layer. It may be an EL element.
As a case where a plurality of light emitting layers are laminated, for example, an organic EL element 1A shown in FIG. 5 is exemplified. The organic EL element 1A includes an organic layer 10A. The organic layer 10A includes a first organic layer (barrier layer) 5 and a first organic layer (barrier layer) 5 between the hole injection / transport layer 7 and the electron injection / transport layer 8. 1 is different from the organic EL element 1 shown in FIG. 1 in that the second organic layer (first light emitting layer) 61 and the second light emitting layer 62 are provided in this order from the anode 3 side. The first organic layer 5 and the first light emitting layer 61 are provided adjacent to each other, and the first material contained in the first organic layer 5 and the thermally activated delayed fluorescence contained in the second organic layer 61 are provided. The material or the light emitting material satisfies the conditions described in the above embodiment. In other respects, the organic EL element 1 </ b> A is configured similarly to the organic EL element 1.

[Electronics]
The organic EL element which concerns on one Embodiment of this invention can be used for electronic devices, such as a display apparatus and a light-emitting device. Examples of the display device include display components such as an organic EL panel module, a television, a mobile phone, a tablet, or a personal computer. Examples of the light emitting device include lighting or a vehicular lamp.

  In addition, the specific structure and shape in the implementation of the present invention may be other structures as long as the object of the present invention can be achieved.

  Hereinafter, examples according to the present invention will be described, but the present invention is not limited to these examples.

  The compounds used in this example are shown.

<Evaluation of compound>
Next, the physical properties of the compounds used in this example were measured. The measurement method and calculation method are shown below, and the measurement results and calculation results are shown in Table 5.

-Ionization potential It measured using the photoelectron spectrometer (the Riken Keiki Co., Ltd. product: AC-3) in air | atmosphere. Specifically, the measurement was performed by irradiating the material with light and measuring the amount of electrons generated by charge separation at that time.

-Light emission maximum peak wavelength A light emission maximum peak wavelength means the peak wavelength of the peak in which intensity | strength becomes the maximum in the light emission wavelength of an organic material. First, a sample for measuring an emission maximum peak wavelength was prepared. A compound to be measured was deposited on a quartz substrate by a vacuum deposition method to form a film having a thickness of 100 nm, and this was used as a sample for measuring the maximum emission peak wavelength. The sample for light emission maximum peak wavelength was irradiated with excitation light at room temperature (300 [K]), and the fluorescence intensity was measured. In the fluorescence spectrum, the vertical axis represents fluorescence intensity and the horizontal axis represents wavelength.
For measurement of the fluorescence spectrum, an F-4500 type spectrofluorometer manufactured by Hitachi High-Technology Co., Ltd. was used.
From the obtained fluorescence spectrum, the wavelength λ _{F at} which the fluorescence intensity was maximum was defined as the emission maximum peak wavelength.

<Production and Evaluation of Organic EL Element>
An organic EL element was produced and evaluated as follows.

Example 1
A glass substrate (manufactured by Geomatic Co., Ltd.) with an ITO transparent electrode (anode) having a thickness of 25 mm × 75 mm × 1.1 mm was subjected to ultrasonic cleaning for 5 minutes in isopropyl alcohol, and then UV ozone cleaning was performed for 30 minutes. The film thickness of ITO was 130 nm.
The glass substrate with the transparent electrode line after the cleaning is mounted on the substrate holder of the vacuum deposition apparatus, and the compound NPD is first deposited on the surface where the transparent electrode line is formed so as to cover the transparent electrode, and the film thickness is 30 nm. The NPD film was formed.
Following the formation of the NPD film, a compound CBP was vapor-deposited to form a CBP film having a thickness of 5 nm on the NPD film. This CBP film corresponds to the first organic layer (barrier layer).
Next, CBP as the third material and compound EM-1 as the second material (thermally active delayed fluorescent material) are co-evaporated on this CBP film, and a second organic layer (light emission) with a thickness of 15 nm is formed. Layer). The concentration of the thermally activated delayed fluorescent material in the light emitting layer (light emitting material concentration) was 6% by mass.
On this light emitting layer, the compound TPBi was vapor-deposited to form a TPBi film having a thickness of 65 nm.
Furthermore, LiF was vapor-deposited on the TPBi film to form a 1 nm-thick LiF film.
Metal Al was vapor-deposited on this LiF film to form a metal cathode having a thickness of 80 nm.
A device arrangement of the organic EL device of Example 1 is schematically shown as follows.
ITO (130) / NPD (30) / CBP (5) / CBP: EM-1 (15, 6%) / TPBi (65) / LiF (1) / Al (80)
The numbers in parentheses indicate the film thickness (unit: nm). Also, in the parentheses, the number displayed as a percentage indicates the ratio (mass%) of the component added, such as the light emitting material in the light emitting layer.

(Examples 2 to 4)
The organic EL elements of Examples 2 to 4 were produced in the same manner as in Example 1 except that the thermally active delayed fluorescent material concentration in the organic EL element of Example 1 was changed.
The luminescent material concentration in each example was 12% by mass in Example 2, 24% by mass in Example 3, and 50% by mass in Example 4.

(Example 5)
The organic EL device of Example 5 was produced in the same manner as in Example 1 except that the compound deposited on the NPD film of Example 1 was changed to mCP and an mCP film was formed on the NPD film.
A device arrangement of the organic EL device of Example 5 is schematically shown as follows.
ITO (130) / NPD (30) / mCP (5) / CBP: EM-1 (15, 6%) / TPBi (65) / LiF (1) / Al (80)

(Examples 6 to 8)
The organic EL elements of Examples 6 to 8 were produced in the same manner as in Example 5 except that the thermally active delayed fluorescent material concentration in the organic EL element of Example 5 was changed.
The thermally active delayed fluorescent material concentration in each example was 12% by mass in Example 6, 24% by mass in Example 7, and 50% by mass in Example 8.

(Comparative Example 1)
The organic EL device of Comparative Example 1 was produced in the same manner as in Example 1 except that the light emitting layer was formed directly on the NPD film without forming the CBP film on the NPD film of Example 1.
A device arrangement of the organic EL device of Comparative Example 1 is schematically shown as follows.
ITO (130) / NPD (30) / CBP: EM-1 (15, 6%) / TPBi (65) / LiF (1) / Al (80)
The numbers in parentheses indicate the film thickness (unit: nm). Also, in the parentheses, the number displayed as a percentage indicates the ratio (mass%) of the component added, such as the light emitting material in the light emitting layer.

(Comparative Examples 2 to 4)
The organic EL elements of Comparative Examples 2 to 4 were produced in the same manner as Comparative Example 1 except that the thermally active delayed fluorescent material concentration in the organic EL element of Comparative Example 1 was changed.
The thermally active delayed fluorescent material concentration in each example was 12% by mass in Comparative Example 2, 24% by mass in Comparative Example 3, and 50% by mass in Comparative Example 4.

(Comparative Example 5)
A glass substrate (manufactured by Geomatic Co., Ltd.) with an ITO transparent electrode (anode) having a thickness of 25 mm × 75 mm × 1.1 mm was subjected to ultrasonic cleaning for 5 minutes in isopropyl alcohol, and then UV ozone cleaning was performed for 30 minutes. The film thickness of ITO was 130 nm.
The glass substrate with the transparent electrode line after the cleaning is mounted on the substrate holder of the vacuum deposition apparatus, and first, the compound HI2 is deposited on the surface where the transparent electrode line is formed so as to cover the transparent electrode, and the film thickness is 60 nm. The compound HI2 film was formed. This HI2 film functions as a hole injection layer.
Subsequent to the formation of the HI2 film, the compound HT3 was vapor-deposited, and an HT3 film having a thickness of 10 nm was formed on the HI2 film. This HT3 film functions as a hole transport layer.
Further, on the HT3 film, the compound H2 and the compound D2 as the light emitting material were co-evaporated to form a light emitting layer having a thickness of 40 nm. The concentration of the luminescent material was 0.5% by mass.
Compound ET1 was vapor-deposited on this light emitting layer to form a compound ET1 film having a thickness of 30 nm. This compound ET1 film functions as an electron transport layer.
LiF was vapor-deposited on this electron transport layer to form a 1 nm-thick LiF layer.
Metal Al was vapor-deposited on this LiF film to form a metal cathode having a thickness of 150 nm.
A device arrangement of the organic EL device of Comparative Example 1 is schematically shown as follows.
ITO (130) / HI2 (60) / HT3 (10) / H2: D2 (40, 0.5%) / ET1 (30) / LiF (1) / Al (150)
The numbers in parentheses indicate the film thickness (unit: nm). Also, in the parentheses, the number displayed as a percentage indicates the ratio (mass%) of the component added, such as the light emitting material in the light emitting layer.

(Comparative Examples 6-8)
The organic EL elements of Comparative Examples 6 to 8 were produced in the same manner as Comparative Example 5 except that the luminescent material concentration in the organic EL element of Comparative Example 5 was changed.
The luminescent material concentration in each comparative example was 1 mass% in comparative example 6, 2 mass% in comparative example 7, and 3 mass% in comparative example 8.

[Evaluation of organic EL elements]
The following evaluation was performed about the organic EL element produced in Examples 1-8 and Comparative Examples 1-8. The evaluation results are shown in Table 6.

-Drive voltage The voltage (unit: V) when electricity was supplied between ITO and Al so that a current density might be 10 mA / cm < ² > was measured.

Luminance and CIE1931 chromaticity current density upon application of a voltage to the device so that 10 mA / cm ² intensity (unit: cd ^{/ m} 2), and CIE1931 chromaticity coordinates (x, y) a spectroradiometer It measured with CS-1000 (made by Konica Minolta).

・ Current efficiency L / J and power efficiency η
A spectral radiance spectrum when a voltage was applied to the device so that the current density was 10 mA / cm ² was measured with a spectral radiance meter CS-1000, and current efficiency L / J ( Unit: cd / A) and power efficiency η (unit: lm / W) were calculated.

・ Main peak wavelength λ _p
The main peak wavelength λ _p (unit: nm) was determined from the obtained spectral radiance spectrum.

・ External quantum efficiency EQE
A spectral radiance spectrum when a voltage was applied to the device so that the current density was 10 mA / cm ² was measured with a spectral radiance meter CS-1000. From the obtained spectral radiance spectrum, the external quantum efficiency EQE (unit:%) was calculated on the assumption that Lambtian radiation was performed.

As the results of the organic EL elements of Examples 1 to 4 and Examples 5 to 8 show, it has been found that the drive voltage decreases as the concentration of the thermally activated delayed fluorescent material increases.
Further, the luminous efficiencies of the organic EL elements of Examples 1 to 4 and Examples 5 to 8 are higher in the concentration of the thermally activated delayed fluorescent material than the organic EL elements of Comparative Examples 1 to 4 and Comparative Examples 5 to 8. It turned out to be highly efficient.
In the organic EL elements of Comparative Examples 1 to 4, the effect of forming an exciplex was noticeable due to the increase in the concentration of the light emitting material, and the light emission efficiency was lowered.
In the organic EL elements of Comparative Examples 5 to 8, it was found that the emission efficiency was greatly reduced despite the narrow range of the light emitting material concentration from 0.5 mass% to 3 mass%.
In the organic EL elements of Comparative Examples 5 to 8, a decrease in light emission efficiency was observed in a low concentration region, and the concentration quenching in the light emitting material was more than the influence of forming an exciplex as in the organic EL elements of Comparative Examples 1 to 4. This is considered to be the result. Comparative Examples 5 to 8 are organic EL elements using typical fluorescent materials, and show that the influence of concentration quenching is extremely large.
In addition, the compound D2 used as a light emitting material in the organic EL elements of Comparative Examples 5 to 8 is not a delayed fluorescent light emitting property but a fluorescent light emitting compound. It is described that the compound D2 is a fluorescent light-emitting dopant material in JP2011-508368A and US Patent Application Publication No. 2005/0249972.

(Example 9 to Example 31)
In Examples 9 to 31, in addition to the above compounds, the following compounds were used.

  The ionization potential was measured as described above. The measurement results are shown below.

Example 9
A glass substrate (manufactured by Geomatic Co., Ltd.) with an ITO transparent electrode (anode) having a thickness of 25 mm × 75 mm × 1.1 mm was subjected to ultrasonic cleaning for 5 minutes in isopropyl alcohol, and then UV ozone cleaning was performed for 30 minutes. The film thickness of ITO was 130 nm.
The glass substrate with the ITO transparent electrode line after washing was mounted on the substrate holder of the vacuum deposition apparatus. First, the compound HI1 was vapor-deposited so as to cover the ITO transparent electrode on the surface on which the ITO transparent electrode line was formed, thereby forming a HI1 film having a thickness of 5 nm.
Following the formation of the HI1 film, the compound HT1 was vapor-deposited, and an HT1 film having a thickness of 20 nm was formed on the HI1 film.
Subsequent to the formation of the HT1 film, the compound HT2 was vapor-deposited, and an HT2 film having a thickness of 5 nm was formed on the HI1 film.
Subsequent to the formation of the HT2 film, the compound EB1 was vapor-deposited to form an EB1 film having a thickness of 5 nm on the HT2 film. This EB1 film corresponds to a first organic layer (barrier layer).
Next, on this EB1 film, the compound H3 as the third material and the compound EM-1 as the second material (thermally active delayed fluorescent material) are co-evaporated to form a second organic layer (thickness 25 nm) A light emitting layer) was formed. The concentration of the thermally activated delayed fluorescent material in the light emitting layer (light emitting material concentration) was 50 mass%.
On this light emitting layer, compound HB1 was vapor-deposited to form a 5 nm thick HB1 film.
Further, the compound ET2 was deposited on the HB1 film to form an ET2 film having a thickness of 50 nm.
LiF was vapor-deposited on this ET2 film to form a 1-nm thick LiF film.
Metal Al was vapor-deposited on this LiF film to form a metal cathode having a thickness of 80 nm.
A device arrangement of the organic EL device of Example 9 is schematically shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB1 (5) / H3: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 10)
The organic EL device of Example 10 was produced in the same manner as in Example 9 except that Compound EB2 was used instead of Compound EB1 in Example 9.
A device arrangement of the organic EL device of Example 10 is schematically shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB2 (5) / H3: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 11)
The organic EL device of Example 11 was produced in the same manner as in Example 9 except that Compound EB3 was used instead of Compound EB1 in Example 9.
A device arrangement of the organic EL device of Example 11 is schematically shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB3 (5) / H3: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 12)
The organic EL device of Example 12 was produced in the same manner as in Example 9 except that Compound EB4 was used instead of Compound EB1 in Example 9.
A device arrangement of the organic EL device of Example 12 is schematically shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB4 (5) / H3: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 13)
The organic EL device of Example 13 was produced in the same manner as in Example 9 except that Compound EB5 was used instead of Compound EB1 in Example 9.
A device arrangement of the organic EL device of Example 13 is schematically shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB5 (5) / H3: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 14)
The organic EL device of Example 14 was produced in the same manner as in Example 9 except that Compound EB6 was used instead of Compound EB1 in Example 9.
A device arrangement of the organic EL device of Example 14 is schematically shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB6 (5) / H3: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 15)
The organic EL device of Example 15 was produced in the same manner as in Example 9 except that Compound EB7 was used instead of Compound EB1 in Example 9.
A device arrangement of the organic EL device of Example 15 is schematically shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB7 (5) / H3: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 16)
The organic EL device of Example 16 was produced in the same manner as in Example 9 except that Compound EB8 was used instead of Compound EB1 in Example 9.
A device arrangement of the organic EL device of Example 16 is schematically shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB8 (5) / H3: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 17)
The organic EL device of Example 17 was produced in the same manner as in Example 9 except that Compound EB9 was used instead of Compound EB1 in Example 9.
A device arrangement of the organic EL device of Example 17 is schematically shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB9 (5) / H3: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 18)
The organic EL device of Example 18 was produced in the same manner as in Example 9 except that Compound EB10 was used instead of Compound EB1 in Example 9.
A device arrangement of the organic EL device of Example 18 is schematically shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB10 (5) / H3: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 19)
The organic EL device of Example 19 was produced in the same manner as in Example 9 except that Compound EB11 was used instead of Compound EB1 in Example 9.
A device arrangement of the organic EL device of Example 19 is schematically shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB11 (5) / H3: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 20)
The organic EL device of Example 20 was produced in the same manner as in Example 9 except that Compound EB12 was used instead of Compound EB1 in Example 9.
A device arrangement of the organic EL device of Example 20 is schematically shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB12 (5) / H3: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 21)
The organic EL device of Example 21 was prepared in the same manner as in Example 9, except that Compound EB3 was used instead of Compound EB1 in Example 9, and Compound H4 was used instead of Compound 3.
A device arrangement of the organic EL device of Example 21 is roughly shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB3 (5) / H4: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 22)
The organic EL device of Example 22 was produced in the same manner as in Example 21 except that Compound EB4 was used instead of Compound EB1 in Example 21.
A device arrangement of the organic EL device of Example 22 is roughly shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB4 (5) / H4: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 23)
The organic EL device of Example 23 was produced in the same manner as in Example 21 except that Compound EB13 was used instead of Compound EB1 in Example 21.
A device arrangement of the organic EL device of Example 23 is roughly shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB13 (5) / H4: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 24)
The organic EL device of Example 24 was produced in the same manner as in Example 21 except that Compound EB5 was used instead of Compound EB1 in Example 21.
A device arrangement of the organic EL device of Example 24 is roughly shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB5 (5) / H4: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 25)
The organic EL device of Example 25 was produced in the same manner as in Example 21 except that Compound EB6 was used instead of Compound EB1 in Example 21.
A device arrangement of the organic EL device of Example 25 is schematically shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB6 (5) / H4: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 26)
The organic EL device of Example 26 was produced in the same manner as in Example 21 except that Compound EB7 was used instead of Compound EB1 in Example 21.
A device arrangement of the organic EL device of Example 26 is roughly shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB7 (5) / H4: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 27)
The organic EL device of Example 27 was produced in the same manner as in Example 21 except that Compound EB8 was used instead of Compound EB1 in Example 21.
A device arrangement of the organic EL device of Example 27 is roughly shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB8 (5) / H4: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 28)
The organic EL device of Example 28 was produced in the same manner as in Example 21 except that Compound EB9 was used instead of Compound EB1 in Example 21.
A device arrangement of the organic EL device of Example 28 is roughly shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB9 (5) / H4: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 29)
The organic EL device of Example 29 was produced in the same manner as in Example 21 except that Compound EB10 was used instead of Compound EB1 in Example 21.
A device arrangement of the organic EL device of Example 29 is roughly shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB10 (5) / H4: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 30)
The organic EL device of Example 30 was produced in the same manner as in Example 21 except that Compound EB11 was used instead of Compound EB1 in Example 21.
A device arrangement of the organic EL device of Example 30 is schematically shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB11 (5) / H4: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

(Example 31)
The organic EL device of Example 31 was produced in the same manner as in Example 21 except that Compound EB12 was used instead of Compound EB1 in Example 21.
A device arrangement of the organic EL device of Example 31 is schematically shown as follows.
ITO (130) / HI1 (5) / HT1 (20) / HT2 (5) / EB12 (5) / H4: EM-1 (25, 50%) / HB1 (5) / ET2 (50) / LiF (1 ) / Al (80)

[Evaluation of organic EL elements]
About the organic EL element produced in Examples 9-31, evaluation similar to the evaluation mentioned above was performed. The evaluation results are shown in Tables 8 and 9.

  According to the organic EL elements of Examples 9 to 31, it was found that the luminous efficiency was high and the driving voltage was lowered.

      DESCRIPTION OF SYMBOLS 1 ... Organic EL element, 2 ... Substrate, 3 ... Anode, 4 ... Cathode, 5 ... Barrier layer (first organic layer), 6 ... Light emitting layer (second organic layer), 7 ... Hole injection / transport layer , 8 ... Electron injection / transport layer, 10 ... Organic layer.

Claims (13)

The anode,
A cathode,
A first organic layer provided between the anode and the cathode;
A second organic layer provided between the cathode and the first organic layer and adjacent to the first organic layer,
The first organic layer contains a first material,
The second organic layer contains the second material at a concentration of 12% by mass or more,
The second material is a thermally activated delayed fluorescent material;
The ionization potential IP _B of the first material and the ionization potential IP _T of the thermally activated delayed fluorescent material satisfy the relationship of the following formula (Equation 1):
The thermally activated delayed fluorescent material has a partial structure represented by the following general formula (1) and a partial structure represented by the following general formula (2) in one molecule.
IP _B > IP _T (1)

(In the general formula (1), CN is a cyano group, and n is an integer of 1 or more.
Z _{1 to} Z ₆ are each independently a nitrogen atom, a carbon atom bonded to CN, or a carbon atom bonded to another atom in the molecule of the thermally activated delayed fluorescent material.
The 6-membered ring structure represented by the general formula (1) may construct a ring structure at an arbitrary position. )

(In the general formula (2), F and G each independently represent a ring structure.
m is 0 or 1.
When m is 1, Y ₁ represents a single bond, an oxygen atom, a sulfur atom, a selenium atom, a carbon atom, a silicon atom, or a germanium atom. ) The organic electroluminescent device according to claim 1 ,
The general formula (2) is represented by at least one of the following general formula (3) and the following general formula (4).


(In the general formula (4), E represents a ring structure represented by the following general formula (5) or a ring structure represented by the following general formula (6). Condensed at any position with the structure.
c is an integer of 1 or more and 4 or less. When c is an integer of 2 or more and 4 or less, the plurality of ring structures E may be the same as or different from each other. )


(In the general formula (6), Z ₇ represents a carbon atom, a nitrogen atom, a sulfur atom, or an oxygen atom.) In the organic electroluminescent element according to claim 1 or 2 ,
The thermally activated delayed fluorescent material is represented by the following general formula (20), and is an organic electroluminescence element.

(In the general formula (20),
A is represented by the general formula (1), provided that in the general formula (1), CN is a cyano group, n is an integer of 1 or more,
Z _{1 to} Z ₆ are each independently a nitrogen atom, a carbon atom bonded to CN, a carbon atom bonded to R, a carbon atom bonded to L, or a carbon atom bonded to D, Z _{1 to} Z ₆ And at least one carbon atom bonded to CN, at least one carbon atom bonded to L or D,
Each R is independently
Hydrogen atom,
A substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms,
A substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms;
A substituted or unsubstituted alkyl group having 1 to 30 carbon atoms,
A substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms,
A substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms,
A substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms,
A substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms,
A substituted or unsubstituted alkylamino group having 2 to 30 carbon atoms,
A substituted or unsubstituted arylamino group having 6 to 60 ring carbon atoms,
A substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms.
D is represented by the general formula (2), provided that the ring structure F and the ring structure G in the general formula (2) may be unsubstituted or have a substituent,
m is 0 or 1,
When m is 1, Y ₁ represents a single bond, an oxygen atom, a sulfur atom, a selenium atom, a carbonyl group, CR ₂₁ R ₂₂ , SiR ₂₃ R ₂₄ or GeR ₂₅ R ₂₆ , and R _{21 to} R ₂₆ are , Synonymous with R.
L is
(I) When intervening between A and D Single bond, substituted or unsubstituted aromatic hydrocarbon group having 6 to 14 ring carbon atoms, substituted or unsubstituted ring atoms having 5 to 14 ring atoms Heterocyclic group, CR ₈₁ R ₈₂ , NR ₈₃ , O, S, SiR ₈₄ R ₈₅ , CR ₈₆ R ₈₇ -CR ₈₈ R ₈₉ , CR ₉₀ = CR ₉₁ , NR ₉₂ , N = CR ₉₃ , substituted or unsubstituted An aliphatic hydrocarbon ring group, or a substituted or unsubstituted aliphatic heterocyclic group, and R _{81 to} R ₉₃ are each independently synonymous with R,
(Ii) When located at the terminal in the molecule of the thermally activated delayed fluorescent material, it is synonymous with R,
f is an integer of 1 or more,
e and g are each independently an integer of 0 or more;
When A is plural, they may be the same or different from each other,
When there are a plurality of D, they may be the same or different from each other,
When L is plural, they may be the same or different. ) In the organic electroluminescent element according to any one of claims 1 to 3 ,
The difference ΔST (M2) between the singlet energy S (M2) of the second material and the energy gap T _77K (M2) at 77 [K] of the second material satisfies the following formula (Equation 3). An organic electroluminescence device characterized by the above.
ΔST (M2) = S (M2) −T _77K (M2) <0.3 [eV] (Expression 3) In the organic electroluminescent element according to any one of claims 1 to 4 ,
An organic electroluminescence device, wherein the ionization potential of the first material is 6.0 eV or more. In the organic electroluminescent element according to any one of claims 1 to 5 ,
An organic electroluminescence device, wherein the ionization potential of the second material is 5.9 eV or less. The anode,
A cathode,
A first organic layer provided between the anode and the cathode;
A second organic layer provided between the cathode and the first organic layer and adjacent to the first organic layer,
The first organic layer contains a first material,
The second organic layer contains a light emitting material having a partial structure represented by the following general formula (1) and a partial structure represented by the following general formula (2) in one molecule,
The second organic layer contains the light emitting material at a concentration of 12% by mass or more,
The emission maximum peak wavelength of the light emitting material is 510 nm or more,
An organic electroluminescence device, wherein the ionization potential IP _B of the first material and the ionization potential IP _E of the light emitting material satisfy a relationship of the following mathematical formula (Equation 2).
IP _B > IP _E (Expression 2)

(In the general formula (1), CN is a cyano group, and n is an integer of 1 or more.
Z _{1 to} Z ₆ are each independently a nitrogen atom, a carbon atom bonded to CN, or a carbon atom bonded to another atom in the molecule of the light emitting material.
The 6-membered ring structure represented by the general formula (1) may construct a ring structure at an arbitrary position. )

(In the general formula (2), F and G each independently represent a ring structure.
m is 0 or 1.
When m is 1, Y ₁ represents a single bond, an oxygen atom, a sulfur atom, a selenium atom, a carbon atom, a silicon atom, or a germanium atom. ) The organic electroluminescence device according to claim 7 ,
The general formula (2) is represented by at least one of the following general formula (3) and the following general formula (4).


(In the general formula (4), E represents a ring structure represented by the following general formula (5) or a ring structure represented by the following general formula (6). Condensed at any position with the structure.
c is an integer of 1 or more and 4 or less. When c is an integer of 2 or more and 4 or less, the plurality of ring structures E may be the same as or different from each other. )


(In the general formula (6), Z ₇ represents a carbon atom, a nitrogen atom, a sulfur atom, or an oxygen atom.) In the organic electroluminescent element according to claim 7 or 8 ,
The said luminescent material is represented by following General formula (20), The organic electroluminescent element characterized by the above-mentioned.

(In the general formula (20),
A is represented by the general formula (1), provided that in the general formula (1), CN is a cyano group, n is an integer of 1 or more,
Z _{1 to} Z ₆ are each independently a nitrogen atom, a carbon atom bonded to CN, a carbon atom bonded to R, a carbon atom bonded to L, or a carbon atom bonded to D;
Among Z _{1 to} Z ₆ , there is at least one carbon atom bonded to CN, and at least one carbon atom bonded to L or D.
Each R is independently
Hydrogen atom,
A substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms,
A substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms;
A substituted or unsubstituted alkyl group having 1 to 30 carbon atoms,
A substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms,
A substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms,
A substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms,
A substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms,
A substituted or unsubstituted alkylamino group having 2 to 30 carbon atoms,
A substituted or unsubstituted arylamino group having 6 to 60 ring carbon atoms,
A substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms.
D is represented by the general formula (2), provided that the ring structure F and the ring structure G in the general formula (2) may be unsubstituted or have a substituent,
m is 0 or 1,
When m is 1, Y ₁ represents a single bond, an oxygen atom, a sulfur atom, a selenium atom, a carbonyl group, CR ₂₁ R ₂₂ , SiR ₂₃ R ₂₄ or GeR ₂₅ R ₂₆ , and R _{21 to} R ₂₆ are , Synonymous with R.
L is
(I) When intervening between A and D Single bond, substituted or unsubstituted aromatic hydrocarbon group having 6 to 14 ring carbon atoms, substituted or unsubstituted ring atoms having 5 to 14 ring atoms Heterocyclic group, CR ₈₁ R ₈₂ , NR ₈₃ , O, S, SiR ₈₄ R ₈₅ , CR ₈₆ R ₈₇ -CR ₈₈ R ₈₉ , CR ₉₀ = CR ₉₁ , NR ₉₂ , N = CR ₉₃ , substituted or unsubstituted An aliphatic hydrocarbon ring group, or a substituted or unsubstituted aliphatic heterocyclic group, and R _{81 to} R ₉₃ are each independently synonymous with R,
(Ii) when located at the terminal in the molecule of the luminescent material, it is synonymous with R,
f is an integer of 1 or more,
e and g are each independently an integer of 0 or more;
When A is plural, they may be the same or different from each other,
When there are a plurality of D, they may be the same or different from each other,
When L is plural, they may be the same or different. ) In the organic electroluminescent element according to any one of claims 7 to 9 ,
A difference ΔST (M2) between a singlet energy S (M2) of the light emitting material and an energy gap T _77K (M2) at 77 [K] of the light emitting material satisfies the following formula (Equation 4): Organic electroluminescence device.
ΔST (M2) = S (M2) −T _77K (M2) <0.3 [eV] (Equation 4) In the organic electroluminescent element according to any one of claims 7 to 10 ,
An organic electroluminescence device, wherein the ionization potential of the first material is 6.0 eV or more. In the organic electroluminescent element according to any one of claims 7 to 11 ,
The ionization potential of the light emitting material is 5.9 eV or less. An electronic apparatus comprising the organic electroluminescence element according to any one of claims 1 to 12 .