JP6215674B2 - 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.
Fluorescent organic EL devices that use light emitted from singlet excitons are said to have a limit of 25% internal quantum efficiency and are being applied to full-color displays such as mobile phones and TVs. In addition to singlet excitons, Therefore, further efficiency improvement using triplet excitons was expected.

  Against this background, highly efficient fluorescent organic EL elements using delayed fluorescence have been proposed and studied.

For example, a TADF (Thermally Activated Delayed Fluorescence, heat activated delayed fluorescence) mechanism has been studied. In this TADF mechanism, when a material having a small energy difference (ΔST) between a singlet level and a triplet level is used, a reverse intersystem crossing from a triplet exciton to a singlet exciton is thermally generated. It uses the phenomenon. For example, Patent Document 1 and Non-Patent Document 1 disclose organic EL elements using the TADF mechanism.
Patent Document 1 discloses a light-emitting layer containing a delayed fluorescent material and a hole blocking layer containing a hole blocking material having a heteroatom such as a nitrogen atom, an oxygen atom, a sulfur atom, a phosphorus atom, a boron atom, or a fluorine atom The organic EL element provided with these is described.
Non-Patent Document 1 discloses an isophthalonitrile derivative having four carbazolyl groups ((4s, 6s) -2,4,5,6-tetra (9H-carbazol-9-yl) isophthalonitrile (4CzIPN)), m An organic EL device having a light-emitting layer containing —CBP (3,3′-di (9H-carbazol-9-yl) biphenyl) and a hole blocking layer containing a compound having a triazine ring (T2T) Have been described.

International Publication No. 2013/154064

Hajime Nakanotani et al., Scientific Reports, 3, 2127, 2013 (doi: 10.1038 / srep02127)

  However, it is necessary to further extend the life of the organic EL element.

  The objective of this invention is providing the organic electroluminescent element with a long lifetime, and providing the electronic device provided with the said organic electroluminescent element.

An organic electroluminescence device according to an aspect of the present invention includes an anode, a cathode, a light emitting layer, and an adjacent layer adjacent to the light emitting layer, and the light emitting layer is a first layer that exhibits thermally activated delayed fluorescence. Containing the compound, the adjacent layer contains a second compound that is an aromatic hydrocarbon compound, the second compound does not contain a heteroatom , and the gap is between the light emitting layer and the cathode. An adjacent layer, and an electron transport layer between the adjacent layer and the cathode .

  An electronic device according to one embodiment of the present invention includes the organic electroluminescence element according to one embodiment of the present invention described above.

  ADVANTAGE OF THE INVENTION According to this invention, the organic electroluminescent element with a long lifetime can be provided, and the electronic device provided with the said organic electroluminescent element can be provided.

It is a figure which shows schematic structure of an example of the organic electroluminescent element which concerns on 1st 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 of the energy level and energy transfer of the 1st compound and 3rd compound in a light emitting layer. It is a figure which shows schematic structure of an example of the organic electroluminescent element which concerns on 2nd embodiment of this invention. It is a figure which shows schematic structure of an example of the organic electroluminescent element which concerns on 3rd 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 a pair of electrodes. This organic layer is formed by laminating a plurality of layers composed of organic compounds. The organic layer may further contain an inorganic compound.
In the organic EL device of this embodiment, at least one of the organic layers is a light emitting layer, and the other layer is an adjacent layer adjacent to the light emitting layer. Therefore, the organic layer may be composed of, for example, one light emitting layer and one adjacent layer, or an organic EL element such as a hole injection layer, a hole transport layer, an electron injection layer, or an electron transport layer. You may have the layer employ | adopted and you may have a 2nd adjacent layer.

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 light emitting layer 5, an adjacent layer 6 adjacent to the light emitting layer, a hole injection / transport layer 7 provided between the light emitting layer 5 and the anode 3, and the adjacent layer 6 and the cathode 4. It has an electron injection / transport layer 8 provided therebetween. In the organic EL element of the present embodiment, the light emitting layer 5 contains a first compound that exhibits thermally activated delayed fluorescence, and the adjacent layer 6 contains a second compound that is an aromatic hydrocarbon compound.
The above “hole injection / transport layer” means “at least one of a hole injection layer and a hole transport layer”, and “electron injection / transport layer” means “an electron injection layer and an electron transport layer”. "At least one of them". 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 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 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.

(Light emitting layer)
-1st compound The 1st compound which concerns on this embodiment has the partial structure represented by following General formula (2) and the following General formula (3) in one molecule | numerator.

In the general formula (2), 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 first compound. For example, when Z ₁ is a carbon atom bonded to CN, at least one of the remaining five (Z _{2 to} Z ₆ ) is a carbon atom bonded to another atom in the molecule of the first compound. Become. The other atom may be an atom constituting a partial structure represented by the following general formula (3), or may be an atom constituting a linking group or substituent interposed between the partial structure.
The first compound according to this embodiment may have a 6-membered ring composed of Z _{1 to} Z ₆ as a partial structure, or a condensation composed by further condensing a ring to the 6-membered ring. You may have a ring as a partial structure.

(In the general formula (3), F and G each independently represent a ring structure.
m is 0 or 1.
When m is 1, Y ₂₀ 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 (3), the general formula (3) is represented by the following general formula (30).

  The ring structure F and the ring structure G in the general formula (30) are synonymous with the ring structure F and the ring structure G in the general formula (3).

  In the general formula (3), when m is 1, the general formula (3) is represented by any one of the following general formulas (31) to (37).

  The ring structure F and the ring structure G in the general formulas (31) to (37) have the same meaning as the ring structure F and the ring structure G in the general formula (3).

  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.

  The first compound according to this embodiment is preferably a compound represented by the following general formula (20).

In the general formula (20),
A is represented by the general formula (2). However, in the general formula (2), CN is a cyano group, n is an integer of 1 or more, and Z _{1 to} Z ₆ are independent of each other. Are a carbon atom bonded to CN, 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 a carbon atom bonded to CN among Z _{1 to} Z ₆ And at least one carbon atom bonded to L or D,
Each R is independently a hydrogen atom or a substituent. The substituent in R is a halogen atom, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted ring formation. Aromatic heterocyclic group having 5 to 30 atoms, 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 ring forming carbon number 6-60 arylsilyl groups, substituted or unsubstituted alkoxy groups having 1 to 30 carbon atoms, substituted or unsubstituted aryloxy groups having 6 to 30 ring carbon atoms, substituted or unsubstituted 2 to 30 carbon atoms Alkylamino group, substituted or unsubstituted arylamino group having 6 to 60 ring carbon atoms, substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, and substituted or unsubstituted It is a substituent selected from the group consisting of ring-forming arylthio group having 6 to 30 carbon atoms.

In the general formula (20), D is represented by the general formula (3), provided that the ring structure F and the ring structure G in the general formula (3) may be unsubstituted or have a substituent. Well, m is 0 or 1, and when m is 1, Y ₂₀ is a single bond, oxygen atom, sulfur atom, selenium atom, carbonyl group, CR ₂₁ R ₂₂ , SiR ₂₃ R ₂₄ or GeR _25. represents _{R 26,} R 21 ~R ₂₆ is synonymous with the groups mentioned in the R. In the general formula (3), when m is 1, the general formula (3) is represented by any one of the general formulas (31) to (34) and the following general formulas (38) to (41). 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 aromatic 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, substituted or unsubstituted An aliphatic hydrocarbon ring group, or a substituted or unsubstituted aliphatic heterocyclic group,
R _{81 to} R ₉₁ each independently have the same meaning as R.
In the general formula (20),
(Ii) when L is located at the end in the molecule of the first compound;
L is synonymous with the group mentioned by said 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 A is plural, they may be the same or different.
When D is plural, they may be the same or different.
When L is plural, they may be the same or different.

  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 first compound according to this 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 1st compound which concerns on this embodiment is a low molecular material. Accordingly, the molecular weight is preferably 5000 or less, and the molecular weight is more preferably 3000 or less. The first compound according to the present embodiment includes the partial structures of the general formula (2) and the general formula (3). As a result, the organic EL device including the first compound emits thermally activated delayed fluorescence. Can do.

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

In the general formula (3x), A and B each independently represent a ring structure represented by the following general formula (3c) or a ring structure represented by the following general formula (3d). The ring structure B is condensed with an adjacent ring structure at an arbitrary position.
px and py are each independently an integer of 0 or more and 4 or less, and represent the numbers of the ring structure A and the ring structure B, respectively. When px is an integer of 2 or more and 4 or less, the plurality of ring structures A may be the same as or different from each other. When py is an integer of 2 or more and 4 or less, the plurality of ring structures B may be the same as or different from each other. Therefore, for example, when px is 2, the ring structure A may have two ring structures represented by the following general formula (3c) or two ring structures represented by the following general formula (3d). Alternatively, a combination of one ring structure represented by the following general formula (3c) and one ring structure represented by the following general formula (3d) may be used.

In the general formula (3d), Z ₇ represents a carbon atom, a nitrogen atom, a sulfur atom, or an oxygen atom.

  In the general formula (3x), when px is 0 and c is py, it is represented by the following general formula (3b).

In the general formula (3b), 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 (3b), E represents a ring structure represented by the general formula (3c) or a ring structure represented by the general formula (3d), and the ring structure E represents an adjacent ring structure and Condensation at any position.
Therefore, for example, when c is 2, the two ring structures E may have two ring structures represented by the general formula (3c), or two ring structures represented by the general formula (3d). One ring structure represented by the general formula (3c) may be combined with one ring structure represented by the general formula (3d).

  By simultaneously holding the partial structures of the general formula (2) and the general formula (3) in one molecule, ΔST can be designed to be effectively small.

  The first compound according to this embodiment preferably has a structure represented by the following general formula (3e) in the molecule.

In the general formula (3e), R _{1 to} R ₉ are each independently
Hydrogen atom,
A substituent, or a single bond that binds to another atom in the molecule of the first compound,
The substituent in R _{1 to} R ₉ is a halogen atom, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 5 to 30 ring atoms, substituted Or an 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 group. An 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 ring carbon number A 6 to 60 arylamino group, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, and a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms. It is a substituent selected from the group.
However, at least one of R _{1 to} R ₉ is the single bond.
In the general formula (3e), 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 building this ring structure, that is, in the general formula (3e), 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 (3e), 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, as a case where the ring structure is constructed in the general formula (3e), a case where a condensed 6-membered ring structure is constructed can be considered.

  Moreover, it is preferable that the 1st compound which concerns on this embodiment has the structure represented by the following general formula (3y) in the molecule | numerator.

R _{11 to} R ₁₉ in the general formula (3y) are independently the same as R _{1 to} R ₉ in the general formula (3e).
However, at least one of R _{11 to} R ₁₉ is a single bond that bonds to another atom in the molecule of the first compound.
In the general formula (3y), 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 (3y), A and B each independently represent a ring structure represented by the following general formula (3g) or a ring structure represented by the following general formula (3h), The ring structure B is condensed with an adjacent ring structure at an arbitrary position.
px is the number of the ring structure A, and is an integer of 0 or more and 4 or less. When px is an integer of 2 or more and 4 or less, the plurality of ring structures A may be the same as or different from each other. When py is an integer of 2 or more and 4 or less, the plurality of ring structures A may be the same as or different from each other. py is the number of ring structures B and is an integer of 0 or more and 4 or less. Therefore, for example, when px is 2, the two ring structures A may have two ring structures represented by the following general formula (3g), or two ring structures represented by the following general formula (3h). Or a combination of one ring structure represented by the following general formula (3g) and one ring structure represented by the following general formula (3h).

In the general formula (3g), 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. . R ₂₀ and R ₂₁ are each bonded to a carbon atom constituting the 6-membered ring of the general formula (3g).
In the general formula (3h), 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 (3y), 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.

  In the general formula (3y), when px is 0 and py is c, it is represented by the following general formula (3f).

R _{11 to} R ₁₉ in the general formula (3f) are each independently synonymous with R _{1 to} R ₉ in the general formula (3e).
However, at least one of R _{11 to} R ₁₉ is a single bond that bonds to another atom in the molecule of the first compound.
In the general formula (3f), 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 (3f), E represents a ring structure represented by the general formula (3g) or a ring structure represented by the general formula (3h), and the ring structure E represents 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 two ring structures E may have two ring structures represented by the general formula (3g), or two ring structures represented by the general formula (3h). Or a combination of one ring structure represented by the following general formula (3g) and one ring structure represented by the general formula (3h).

  The first compound according to this embodiment is preferably represented by the following general formula (2A).

In the general formula (2A), n is an integer of 1 or more, t is an integer of 1 or more, and u is an integer of 0 or more.
L _A is a substituted or unsubstituted ring formed C6-30 aromatic hydrocarbon ring or aromatic heterocyclic ring atoms 6 to 30.
CN is a cyano group.
D ₁ and D ₂ are each independently represented by the general formula (3), provided that the ring structure F and the ring structure G in the general formula (3) may be unsubstituted or have a substituent. Well, m is 0 or 1, and when m is 1, Y ₂₀ is a single bond, oxygen atom, sulfur atom, selenium atom, carbonyl group, CR ₂₁ R ₂₂ , SiR ₂₃ R ₂₄ or GeR _25. R ₂₆ represents R ₂₆ , and R _{21 to} R ₂₆ have the same meaning as R. When m is 1, the general formula (3) is represented by any one of the general formulas (31) to (34) and the general formulas (38) to (41).
D ₁ and D ₂ may be the same or different. When t is 2 or more, the plurality of D ₁ may be the same as or different from each other. When u 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.
The aromatic heterocyclic ring atoms 6 to 30 in the L _A, pyridine, pyrimidine, pyrazine, quinoline, quinazoline, phenanthroline, benzofuran, etc. dibenzofuran and the like.

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 may be bonded to the second carbon atom adjacent to the carbon atom. For example, in the compound according to this embodiment, as in the partial structure represented by the following general formula (2B), D is bonded to the first carbon atom C _1, and the compound adjacent to the _first carbon atom C ₁ is adjacent to the _first carbon atom C ₁ . second cyano group to the carbon atom C ₂ may be bonded. D in the following general formula (2B) has the same meaning as D ₁ or D ₂ . In the following general formula (2B), a wavy line portion represents a bonding position with another structure or atom.

And D ₁ or D ₂ having the structure as shown in general formula (3a) or the general formula (3b), is bonded to an aromatic hydrocarbon ring and the 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, the t 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.

  The first compound according to this embodiment is preferably represented by the following general formula (21).

In the general formula (21), A ₃₁ and B ₃₁ are each independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted ring forming atom number of 5 to 5. 30 aromatic heterocyclic groups are represented.
X _{31 to} X ₃₈ and Y _{31 to} Y ₃₈ each independently represent a nitrogen atom, a carbon atom bonded to ^RD , or a carbon atom bonded to L ₃₃ . However, at least one of X _{35 to} X ₃₈ is a carbon atom bonded to L _33, and at least one of Y _{31 to} Y ₃₄ is a carbon atom bonded to L ₃₃ .
R ^D is each independently a hydrogen atom or a substituent, and the substituent in R ^D is
A halogen atom,
A substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms,
A substituted or unsubstituted aromatic heterocyclic group having 5 to 30 ring atoms;
It is a substituent selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms and a substituted or unsubstituted silyl group.
L ₃₁ and L ₃₂ are each independently a single bond or a linking group,
As the linking group for L ₃₁ and L ₃₂ ,
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 multiple linking group in which 2 to 4 groups selected from the aromatic hydrocarbon groups are bonded;
A multiple linking group in which 2 to 4 groups selected from the heterocyclic group are bonded, or a group in which 2 to 4 groups selected from the aromatic hydrocarbon group and the heterocyclic group are bonded It is a multiple linking group.
L ₃₃ represents a substituted or unsubstituted monocyclic hydrocarbon group having 6 or less ring-forming carbon atoms, or a substituted or unsubstituted monocyclic heterocyclic group having 6 or less ring-forming atoms.
w represents an integer of 0 to 3. When w is 0, at least one of X _{35 to} X ₃₈ and at least one of Y _{31 to} Y ₃₄ are directly bonded.
A monocyclic hydrocarbon group is not a condensed ring but a group derived from a single hydrocarbon ring (aliphatic cyclic hydrocarbon or aromatic hydrocarbon), and a monocyclic heterocyclic group is a single ring A group derived from a heterocyclic ring.

Further, in the general formula (21), at least one of the following conditions (i) and (ii) is satisfied.
(I) At least one of A ₃₁ and B ₃₁ is an aromatic hydrocarbon group having 6 to 30 ring carbon atoms substituted with a cyano group, or an aromatic having 6 to 30 ring atoms substituted with a cyano group Group heterocyclic group.
_(Ii) at least one of X 31 _{to X 34} and _Y 35 _{to Y 38} is a carbon atom bonded with ^{R D,} the ^R at least one of ^D is, ring carbon 6 is substituted with a cyano group Or an aromatic heterocyclic group having 6 to 30 ring atoms substituted with an aromatic hydrocarbon group having ˜30 or a cyano group.
However, if R ^D there are a plurality, or different in each of the plurality of R ^D identical.

In the general formula (21), the aromatic hydrocarbon group having 6 to 30 ring carbon atoms or the aromatic heterocyclic group having 6 to 30 ring atoms represented by A ₃₁ and B ₃₁ has a substituent. In the case, the substituent is a cyano group, a halogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, Haloalkoxy group having 1 to 20 carbon atoms, alkylsilyl group having 1 to 10 carbon atoms, aryl group having 6 to 30 ring carbon atoms, aryloxy group having 6 to 30 ring carbon atoms, and aralkyl having 6 to 30 carbon atoms One or more groups selected from the group consisting of a group and a heterocyclic group having 5 to 30 ring atoms are preferable. When it has a plurality of substituents, they may be the same or different.

In the general formula (21), it is preferable that the condition (i) is satisfied and the condition (ii) is not satisfied.
Alternatively, in the general formula (21), it is preferable that the condition (ii) is satisfied and the condition (i) is not satisfied.
Alternatively, it is also preferable to satisfy the condition (i) and the condition (ii).

In the general formula (21), at least one of A ₃₁ and B ₃₁ is
A phenyl group substituted with a cyano group,
A naphthyl group substituted with a cyano group,
A phenanthryl group substituted with a cyano group,
A dibenzofuranyl group substituted with a cyano group,
A dibenzothiophenyl group substituted with a cyano group,
A biphenyl group substituted with a cyano group,
A terphenyl group substituted with a cyano group,
A 9,9-diphenylfluorenyl group substituted with a cyano group,
A 9,9′-spirobi [9H-fluoren] -2-yl group substituted with a cyano group,
A 9,9-dimethylfluorenyl group substituted with a cyano group or a triphenylenyl group substituted with a cyano group is preferred.

In the general formula _(21), at least one of X 31 _{to X 34} and _Y 35 _{to Y 38} are CR _^D, at least one of ^{R D} in X 31 _{to X 34} and _Y 35 _{to Y 38} are,
A phenyl group substituted with a cyano group,
A naphthyl group substituted with a cyano group,
A phenanthryl group substituted with a cyano group,
A dibenzofuranyl group substituted with a cyano group,
A dibenzothiophenyl group substituted with a cyano group,
A biphenyl group substituted with a cyano group,
A terphenyl group substituted with a cyano group,
A 9,9-diphenylfluorenyl group substituted with a cyano group,
A 9,9′-spirobi [9H-fluoren] -2-yl group substituted with a cyano group,
A 9,9-dimethylfluorenyl group substituted with a cyano group or a triphenylenyl group substituted with a cyano group is preferred.

In the general formula (21), it is preferable that X ₃₆ and Y ₃₃ are bonded via L ₃₃ or directly bonded.
In the general formula (21), it is preferable that X ₃₆ and Y ₃₂ are bonded via L ₃₃ or directly bonded.
Further, in the general formula _(21), and the _{X 37} and _{Y 33,} or attached via a _{L 33,} or is preferably bonded directly.

In the general formula (21), w is preferably 0.
Alternatively, in the general formula (21), w is preferably 1.

In the general formula (21), L ₃₁ and L ₃₂ are preferably a single bond or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms.

  Specific examples of the first compound according to this embodiment are shown below. The first compound in the present invention is not limited to these specific examples.

-3rd compound In the organic EL element of this embodiment, the light emitting layer may be comprised only with the 1st compound, and may contain the 3rd compound further. The third compound is preferably an organic compound.
The third compound is a component that disperses the first compound. By adding the third compound, it may be possible to suppress this when the concentration of the first compound is quenched. In addition, when a compound having a triplet energy larger than that of the first compound is used as the third compound, emission efficiency may be improved by efficiently confining the triplet energy in the light emitting layer.

  The third compound is at least one compound selected from the group consisting of a compound having a triphenylene ring, a compound having a dibenzofuran ring, a compound having a dibenzothiophene ring, a silicon-containing aromatic compound, and a phosphorus-containing aromatic compound. It is preferable that As a 3rd compound, you may contain in a light emitting layer as 1 type of compounds, or as 2 or more types of compounds.

  The third compound according to this embodiment may have a partial structure represented by the following general formula (1).

In (Formula _{(1), X 1, X} 2, X 5, X 6, X 11 ~X 14 are each independently a bond with other atoms in the molecule a nitrogen atom or the third compound, Provided that X ₁ and X ₂ , X ₅ and X ₆ , X ₁ and X ₆ , X ₁₁ and X ₁₂ , X ₁₃ and X ₁₄ , and X ₁₂ and X ₁₃ are at least 0 The group of 4 or less is a carbon atom bonded to the structure represented by the following general formula (1a).
Y ₁ is a sulfur atom, an oxygen atom, or a carbon atom. )

(In the general formula (1a), X _{15 to} X ₁₈ are each independently a nitrogen atom or a carbon atom bonded to another atom in the molecule of the third compound.
Y ₃ is a sulfur atom, an oxygen atom, a nitrogen atom, or a carbon atom.
* Is selected from the group consisting of X ₁ and X ₂ , X ₅ and X ₆ , X ₁ and X ₆ , X ₁₁ and X ₁₂ , X ₁₃ and X ₁₄ , and X ₁₂ and X _{13 in} the general formula (1). Shows the bonding site with the carbon atom in the group.
Y ₁ and Y ₃ may be the same or different from each other, and when there are a plurality of Y ₃ , they may be the same or different from each other. )

  In the present embodiment, the third compound is preferably represented by the following general formula (10).

(In the general formula (10), ka and kb are each independently an integer of 1 to 4, preferably an integer of 1 to 3.
_HA is a structure represented by the general formula (1). In the general formula (1), X ₁ , X ₂ , X ₅ , X ₆ , X _{11 to} X ₁₄ are each independently nitrogen. An atom, a carbon atom bonded to R ^A , or a carbon atom bonded to H _B , provided that X ₁ and X ₂ , X ₅ and X ₆ , X ₁ and X ₆ , X ₁₁ and X ₁₂ , X ₁₃ and X ₁₄ , and a group of 0 to 4 in the group of X ₁₂ and X ₁₃ is a carbon atom bonded to the structure represented by the general formula (1a),
In the general formula (1a), X _{15 to} X ₁₈ are each independently a nitrogen atom, a carbon atom bonded to R ^A , or a carbon atom bonded to H _B ,
Y ₁ is a sulfur atom, an oxygen atom, or CR ^X R ^Y ;
Y ₃ is a sulfur atom, an oxygen atom, NR ^B , or CR ^X R ^Y ;
* Is selected from the group consisting of X ₁ and X ₂ , X ₅ and X ₆ , X ₁ and X ₆ , X ₁₁ and X ₁₂ , X ₁₃ and X ₁₄ , and X ₁₂ and X _{13 in} the general formula (1). The bonding sites with carbon atoms in
Y ₁ and Y ₃ may be the same or different from each other, and when there are a plurality of Y ₃ , they may be the same or different from each other.
R ^A , R ^B , R ^X and R ^Y are each independently a hydrogen atom or a substituent, and the substituents in R ^A , R ^B , R ^X and R ^Y are a halogen atom, a cyano group, a substituent Or an unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted ring Aryloxy group having 6 to 30 carbon atoms, substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms, substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, substituted or unsubstituted 3 to 3 carbon atoms 50 alkylsilyl groups, substituted or unsubstituted arylsilyl groups having 6 to 50 ring carbon atoms, substituted or unsubstituted aryl groups having 6 to 30 ring carbon atoms, and substituted Is a substituent selected from the group consisting of heterocyclic group unsubstituted ring atoms 5-30.
When R ^A and R ^B is in plurality, they may be the same or different from each other.
In the general formula (10), H _B represents a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 5 to 30 ring atoms, and the structure H _A group derived from _A , or a group formed by combining 2 or more and 4 or less groups arbitrarily selected from these groups. )

In the present embodiment, X ₁ , X ₂ , X ₅ , X ₆ , and X _{11 to} X ₁₄ are each independently preferably a carbon atom bonded to R ^A or a carbon atom bonded to H _B.

In the present embodiment, Y ₁ and Y ₃ are preferably each independently a sulfur atom or an oxygen atom.

In the present _embodiment, a carbon atom at least one is bound to ^{R A} of _{X 1, X 2, X 5} , X 6, X 11 ~X 14, X 15 ~X 18, R A is represented by the following general formula It is preferably represented by (1b).

(In the general formula (1b), r is an integer of 0 or more and 5 or less, preferably an integer of 0 or more and 2 or less.
In the general formula (1b), Ar ^a is a substituted or unsubstituted arylene group having 6 to 15 ring carbon atoms, or a substituted or unsubstituted heteroarylene group having 5 to 15 ring atoms, and Ar ^a May be the same or different,
Ar ^b is a substituted or unsubstituted aryl group having 6 to 20 ring carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 5 to 20 ring atoms. )

In the present embodiment, Ar ^{a in the} general formula (1b) is preferably a substituted or unsubstituted arylene group having 6 to 15 ring carbon atoms, and more preferably a phenylene group.

In this embodiment, the structure H _B is preferably represented by the following general formula (1c).

(In the general formula (1c), s is an integer of 0 or more and 5 or less, preferably an integer of 0 or more and 2 or less.
Ar ^c is a substituted or unsubstituted ring forming an aryl group having 6 to 20 carbon atoms or a substituted or unsubstituted ring atoms 5-20 aromatic heterocyclic group,
Ar ^d represents a substituted or unsubstituted ring-forming arylene group having a carbon number of 6-15 or a substituted or unsubstituted ring atoms 5-15 heteroarylene group, if the Ar ^d there are a plurality, identical to each other But it can be different. )

In the present embodiment, the structure _HA is preferably represented by any one of the following general formulas (121) to (127).

(In each of the general formulas (121) to (127),
Y ₁ is a sulfur atom, an oxygen atom, or CR ^X R ^Y ;
Y ₃ is a sulfur atom, an oxygen atom, NR ^B , or CR ^X R ^Y ;
Among the plurality of R ^A, at least one is a bond that binds to said structure H _B or the structure H _D, represented by at least one of the general formula (1b), others are each independently a hydrogen atom , A substituent, or a bond that binds to the structure H _A or the structure H _C , and R ^B , R ^X , and R ^Y are each independently a hydrogen atom or a substituent, and this R ^A , The substituent in R ^B , R ^X , and R ^Y is a halogen atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms. Substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms A substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 50 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 50 ring carbon atoms, substituted or It is a substituent selected from the group consisting of an unsubstituted aryl group having 6 to 30 ring carbon atoms and a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms. )

In the present embodiment, the structure _HA is preferably represented by the general formula (121).

Examples of the partial structure represented by the general formula (1) or the structure H _A in the general formula (10) are shown below. These structures, other atoms in the molecule of the third compound, wherein R ^A, and the like wherein the structure H _B, binds.
The partial structure in the third compound of the present invention is not limited to these specific examples.

Structural examples of the structure H _B in the general formula (10), R ^A represented by the general formula (1b), and the structure H _B represented by the general formula (1c) are shown below. These structures, in the molecule of the third compound, represented partial structure and are in the general formula (1), wherein R ^A, binds the like to the H _A. In the following structural examples, * indicates a binding site with another structure. The third compound of the present invention is not limited to these structural examples.

Furthermore, following a structural example of the structure _{H B} in the general formula (10). These structures, in the molecule of the third compound, represented partial structure and are in the general formula (1), wherein R ^A, binds the like to the H _A. In the following structural examples, * indicates a binding site with another structure. The third compound of the present invention is not limited to these structural examples.

In the present embodiment, the third compound is preferably a compound having a triphenylene ring.
Furthermore, the third compound is preferably represented by the following general formula (40).

(In the general formula (40),
X ^{1 to} X ¹² are each independently a nitrogen atom or C—R ^A ,
Each R ^A is independently a hydrogen atom or a substituent, and the substituent in this R ^A is
A halogen atom,
A cyano group,
A substituted or unsubstituted alkyl group having 1 to 20 carbon atoms,
A substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms,
A substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms,
A substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms,
A substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms,
A substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms,
A substituted or unsubstituted alkylsilyl group having 3 to 50 carbon atoms,
A substituted or unsubstituted arylsilyl group having 6 to 50 ring carbon atoms,
It is a substituent selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms and a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms. )

In the general formula (40), at least one of X ^{1 to} X ¹² is C—R ^A ,
It is preferable that at least one of R ^A is represented by the following general formula (1b).

(In the general formula (1b),
r is an integer of 0 to 5,
Ar ^a is a substituted or unsubstituted arylene group having 6 to 15 ring carbon atoms or a substituted or unsubstituted heteroarylene group having 5 to 15 ring atoms, and when ^a plurality of Ar ^a are present, they are the same as each other But it can be different,
Ar ^b is a substituted or unsubstituted aryl group having 6 to 20 ring carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 5 to 20 ring atoms. )

It is preferable that at least one of X ^{1 to} X ¹² in the general formula (40) is a nitrogen atom.
Alternatively, X ^{1 to} X ¹² in the general formula (40) are preferably C—R ^A. In this case, the general formula (40) is represented by the following general formula (1p).

In the general formula (1p), R ^A is independently the same as the groups listed as R ^A in the general formula (40).
It is preferable that at least one of R ^{A in} the general formula (1p) is represented by the general formula (1b). For example, the general formula (1) is preferably represented by the following general formula (1p-1) or the following general formula (1p-2).

In the general formula (1p-1) and the general formula (1p-2), R ^A has the same meaning as R ^A in the general formula (40), and r, Ar ^a , and Ar ^b are each independently , Are the same as r, Ar ^a , and Ar ^b in the general formula (1b).
In the present embodiment, in the general formula (1p-1) and the general formula (1p-2), Ar ^b represents the general formula (1e), the general formula (1f), the general formula (1g), and the general formula. It is preferably represented by any one of the formula (1h), the general formula (1k), the general formula (1m), and the general formula (1n).

  Specific examples of the third compound according to this embodiment are shown below. The third compound in the present invention is not limited to these specific examples.

  In addition, as a 3rd compound, the 2nd compound used for an adjacent layer can also be used.

As the third compound, a compound having a carbazolyl group can also be used.
Examples of the compound having a carbazolyl group include the following compounds.

  In the present embodiment, the carbazolyl group may include, for example, a group in which a ring is further condensed with respect to a carbazole ring as represented by the following formula. Such a group may also have a substituent. Also, the position of the joint can be changed as appropriate.

  Moreover, as a silicon-containing aromatic compound, the following compound can be mentioned, for example.

  Moreover, as a phosphorus containing aromatic compound, the following compound can be mentioned, for example.

-Film thickness of light emitting layer The film thickness of the light emitting layer in the organic EL device of the present embodiment is preferably 5 nm to 50 nm, more preferably 7 nm to 50 nm, and most preferably 10 nm to 50 nm. If the thickness is less than 5 nm, it is difficult to form a light emitting layer and the adjustment of chromaticity may be difficult, and if it exceeds 50 nm, the driving voltage may increase.

-Content rate of the material in a light emitting layer In the organic EL element of this embodiment, when the 3rd compound is contained in the light emitting layer, the ratio of a 1st compound and a 3rd compound is 99 by mass ratio. : 1 or more and 1:99 or less is preferable. In the light emitting layer, the content of the first compound is preferably 5% by mass or more and 80% by mass or less, and more preferably 20% by mass or more and 80% by mass or less.

And manufacturing method first compound of the first compound, for example, a partial structure represented by the general formula (2), is at least one of carbon atom bonded with the halogen atom of Z ₁ to Z ₆ A compound in which a commercially available compound is represented by the general formula (3) in the presence of a catalyst such as tetrakis (triphenylphosphine) palladium and a base, and a hydrogen atom is bonded to a nitrogen atom bonded to the ring structure F and the ring structure G Can be made to react.

-Manufacturing method of 3rd compound A 3rd compound can be manufactured as follows, for example.
For example, when producing a compound having a partial structure represented by the general formula (1), first, in the general formula (1), X ₁ , X ₂ , X ₅ , X ₆ , X _{11 to} X ₁₄ are nitrogen atoms, Alternatively, a commercially available compound that is a carbon atom bonded to a hydrogen atom is used as a starting material. This starting material can be obtained by replacing the hydrogen atom with a halogen atom or an alkyl group by a known method. This halogen atom can be substituted with another group such as an aryl group by a method such as Suzuki coupling.
Further, for example, in the general formula (1), X ₁ and X ₂ are the partial structure is a carbon atom bonded to the structure represented by the general formula (1a), each halogen atom to a carbon atom of X ₁ and X ₂ In the bonded structure, the halogen atom bonded to X ₁ is substituted with an ortho-hydroxyphenyl group or the like by a method such as Suzuki coupling. Thereafter, the halogen atom bonded to X ₂ is obtained by substitution by an intramolecular substitution reaction with the hydroxy group or the like in the presence of a base.
For example, in the case where _HC in the general formula (11) is a material represented by the general formula (110), among X ₁ , X ₂ , X ₅ , X ₆ , and X _{11 to} X _{14 in} the general formula (110) , the leaving group is bonded synthetic intermediate bromine group on the carbon atom bonded to the H _D and (a), in the formula (11), such as a bromine group in the carbon atom bonded to the H _C in the partial structure H _D of It can be produced by cross-coupling with a synthetic intermediate (B) to which a leaving group is bonded. Here, as the cross coupling, for example, a leaving group such as a bromine group in the synthetic intermediate (A) is reacted with bis (pinacolato) diboron or the like in the presence of a catalyst such as tetrakis (triphenylphosphine) palladium to form a boronic ester. Suzuki coupling which is converted into a group and subsequently coupled with the synthetic intermediate (B) in the presence of a basic aqueous solution can be used.
For example, when producing a compound having a partial structure represented by the general formula (40), first, in the general formula (40), X _{1 to} X ₁₂ are a nitrogen atom or a carbon atom bonded to a hydrogen atom. The compound is the starting material. This starting material can be obtained by replacing the hydrogen atom with a halogen atom or an alkyl group by a known method. This halogen atom can be substituted with another group such as an aryl group by a method such as Suzuki coupling.

-Combination of the first compound and the third compound In the present embodiment, it is preferable to use the first compound having the specific structure and the third compound in combination in the light emitting layer.
Therefore, the correlation between the first compound and the third compound based on the transient PL will be described.

FIG. 2 shows a schematic diagram of an exemplary 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 separates 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. Further, when the two-dimensional image is cut out along the wavelength axis, an attenuation curve (transient PL) in which the vertical axis represents the logarithm of the emission intensity and the horizontal axis represents time can be obtained.

  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. Compound D1 corresponds to the first compound 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. Generally, an exciplex is formed by physically joining different kinds of organic molecules. This is because in the exciplex, the emission level is formed on the longer wavelength side 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.

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.

The first compound and the third compound according to this embodiment are preferably 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.
The first compound and the third compound according to the present embodiment include an energy gap Eg _77K (M1) at 77 [K] of the first compound and an energy gap Eg at 77 [K] of the third compound. _77K (M3) is preferably selected from compounds satisfying the relationship of the following mathematical formula (Formula 2). The energy gap at 77 [K] will be described later.
Eg _77K (M3)> Eg _77K (M1) ( _Expression 2)

• For the delayed fluorescence of delayed fluorescence (thermally activated delayed fluorescence) are explained in 261-268 page "Device product organic semiconductor" (Chihaya Adachi Yahen, published by Kodansha). Among them, if the energy difference ΔE ₁₃ between the excited singlet state and the excited triplet state of the fluorescent material can be reduced, the reverse energy transfer from the excited triplet state to the excited singlet state, which usually has a low transition probability, can occur. It is explained that it is generated with high efficiency and thermally stimulated delayed fluorescence (TADF) is expressed, and the generation mechanism of delayed fluorescence is explained in FIG. 10.38. The first compound in the present embodiment is a compound that exhibits thermally activated delayed fluorescence generated by such a mechanism.
The delayed fluorescence emission can be confirmed by transient PL measurement. As described above, by the transient PL measurement, it is possible to obtain a light emission decay curve with the vertical axis representing the emission intensity and the horizontal axis representing the time. Based on this emission decay curve, the fluorescence intensity of fluorescence emitted from the singlet excited state generated by photoexcitation and delayed fluorescence emitted from the singlet excited state generated by reverse energy transfer via the triplet excited state The ratio can be estimated. In the delayed fluorescence emitting material, the ratio of the delayed fluorescence intensity that attenuates slowly is somewhat larger than the fluorescence intensity that decays quickly.
The delayed fluorescence emission amount in this embodiment can be obtained using the apparatus shown in FIG. The first compound is excited with pulsed light having a wavelength that is absorbed by the first compound (light irradiated from a pulse laser) and then promptly observed from the excited state. After the excitation, there is delay light emission (delayed light emission) that is not observed immediately but is observed thereafter. In the present embodiment, the amount of delay light emission (delayed light emission) is preferably 5% or more with respect to the amount of Promp light emission (immediate light emission).
The amounts of Prompt light emission and Delay light emission can be obtained by the same method as described in “Nature 492, 234-238, 2012”. In addition, the apparatus used for calculation of the amount of Promp light emission and Delay light emission is not limited to the thing as described in the said literature.
The sample used for the measurement of delayed fluorescence is, for example, co-evaporation of a first compound and a compound TH-2 described later on a quartz substrate so that the ratio of the first compound is 12% by mass. And what formed the thin film with a film thickness of 100 nm can be used.

・ 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 to each other. In particular, the first compound according to the present embodiment has a CN group that has strong acceptor properties. Therefore, it is considered that the first compound and an amine-based material that is general as a hole transport material of the organic EL element can easily form an exciplex.
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.
Furthermore, the ionization potential of the following reference compound H3 is larger than the ionization potential of the compound D1. Therefore, the combination of the following reference compound H3 and compound D1 can efficiently prevent the formation of an exciplex.

Like reference compound H3, a compound having a partial structure in which two or more six-membered ring structures are condensed to a ring structure containing a sulfur atom or an oxygen atom has an ionization potential higher than that of a carbazole compound such as reference compound H2. Due to its large size, it is difficult to form an exciplex. Further, since the compound has a large triplet energy, the triplet energy of the doping material can be efficiently confined and the structure is strong, so that the lifetime can be increased.
Therefore, in the organic EL element 1 of the present embodiment, the light emission of the organic EL element is achieved by including the first compound and the third compound in the light emitting layer so as to satisfy the relationship of the mathematical formula (Equation 2). Efficiency can be improved and life can be extended.

  Further, in the organic EL device 1 of the present embodiment, it is preferable to combine the ionization potential IP (M1) of the first compound to be smaller than the ionization potential IP (M3) of the third compound. That is, it is preferable that the ionization potential Ip (M3) of the third compound and the ionization potential Ip (M1) of the first compound satisfy the relationship of the following mathematical formula (Formula 3).

    Ip (M3)> Ip (M1) (Equation 3)

In the present embodiment, the ionization potential Ip (M3) of the third compound is preferably 5.9 eV or more.
By satisfying such a relationship, formation of an exciplex can be suppressed.

In the present embodiment, when the first compound having a cyano group is used, an exciplex is easily formed when the third compound is an amine compound. The first compound having a cyano group has a high ionization potential, and the amine compound has a low ionization potential. Therefore, it is considered that an exciplex is easily formed in the light emitting layer.
Therefore, for example, when the first compound having the partial structure represented by the general formula (2) and the partial structure represented by the general formula (3) in one molecule is used, It is preferable to use a non-amine compound as the compound.

  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.

Since the third compound in this embodiment has a large triplet energy, the triplet energy can be efficiently confined in the light emitting layer. In addition, the third compound in the present embodiment is a material that has a high ionization potential, does not easily form an exciplex with the first compound, and does not easily form an association with a small triplet energy. Therefore, the luminous efficiency of the organic EL element can be improved.
In the third compound in the present embodiment, when a compound having appropriate hole transportability and electron transportability in addition to large triplet energy is used, the light emission efficiency may be further improved. Furthermore, when a compound having a rigid structure consisting of a condensed ring is used as the third compound, there is little chemical change due to heat or physical change of the thin film, and the organic EL element can be further extended in life. There is sex.

・ ΔST
In the organic EL device of the present embodiment, the difference ΔST (M1) between the singlet energy EgS (M1) of the first compound and the energy gap Eg _77K (M1) at 77 [K] of the first compound is expressed by the following formula. It is preferable to satisfy (Equation 1).
ΔST (M1) = EgS (M1) −Eg _77K (M1) <0.3 [eV] (Equation 1)
In addition, ΔST (M1) is preferably less than 0.2 [eV].

In order to reduce ΔST which is equivalent to the difference between the singlet energy EgS and the triplet energy EgT, quantum exchange is realized by a small exchange interaction between the singlet energy EgS and the triplet energy EgT. 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 first compound of the present embodiment is a compound in which a donor element and an acceptor element are combined in the molecule, and further, electrochemical stability (redox stability) is considered. And compounds having ΔST of 0 eV or more and less than 0.3 eV.
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 (M1) of the first compound is small, the reverse from the triplet level of the first compound to the singlet level of the first compound is caused by the externally applied thermal energy. Interterm crossing is likely 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 (M1) as the first compound, and from the triplet level of the first compound by the thermal energy given from the outside, Inverse crossing to singlet levels easily occurs.
FIG. 4 shows an example of the relationship between the energy levels of the first compound and the third compound in the light emitting layer. In FIG. 4, S0 represents the ground state, S1 _H represents the lowest excited singlet state of the third compound, T1 _H represents the lowest excited triplet state of the third compound, and S1 _D represents The lowest excited singlet state of the first compound is represented, T1 _D represents the lowest excited triplet state of the first compound, and the dashed arrow represents the energy transfer between each excited state. As shown in FIG. 4, from the lowest excited singlet state S1 _H and the lowest excited triplet state T1 _{H of} the third compound, the lowest excited singlet of the first compound by Forster energy transfer and Dexter energy transfer, respectively. State S1 _D and the lowest excited triplet state T1 _D are generated. Further lowest excited triplet state T1 _D With small material .DELTA.St (M1) as the first compound, the thermal energy, it is possible Gyakuko intersystem crossing to the lowest excited singlet state S1 _D. As a result, fluorescence emission from the lowest excited singlet state S1 _{D of the} first compound 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.

-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 sample in which a compound to be measured is deposited on a quartz substrate or a sample in which a solution dissolved in an appropriate solvent is enclosed in a quartz glass tube is prepared. 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 measurement method is the same as that of the normal triplet energy EgT, but in order to distinguish the difference in strict meaning, the value measured as follows is referred to as an energy gap Eg _77K. . In the case of measuring using a thin film, a sample is prepared by vapor-depositing a compound to be measured on a quartz substrate with a film thickness of 100 nm. 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 Eg _77K .
Conversion formula 1: Eg _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 rising edge of the phosphorescence spectrum on the short wavelength side.
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 EgS
Singlet energy EgS 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: EgS [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.
In addition, when the measurement result using the sample deposited on the quartz substrate and the measurement result using the solution are greatly different, the cause may be the formation of molecular aggregates or strong interaction with the solvent. . Therefore, the above measurement can also be performed using a sample in which a compound to be measured and another appropriate material having a large energy gap and not forming an exciplex are co-deposited on a quartz substrate.

In this embodiment, the difference between the singlet energy EgS and the energy gap Eg _77K is defined as ΔST.

In the organic EL device of the present embodiment, it is preferable that the first compound contained in the light emitting layer emits light.
Moreover, in the organic EL element of this embodiment, it is preferable that the light emitting layer does not contain a metal complex.

(Adjacent layer)
The adjacent layer 6 contains a second compound that is an aromatic hydrocarbon compound. The second compound does not contain heteroatoms. The adjacent layer 6 is preferably composed only of a compound not containing a hetero atom.
Since the second compound is an aromatic hydrocarbon compound having no heterocyclic ring, it is a chemically or photo / electrochemically strong material. Specifically, it is a material having hole resistance, electron resistance or exciton resistance. As a result, according to the organic EL element 1 of the present embodiment in which the adjacent layer 6 contains the second compound, the lifetime can be extended. In particular, in an organic EL element using a delayed fluorescent material having a long excited state period as in this embodiment, the effect of extending the lifetime is great.

The adjacent layer is a layer disposed in contact with the light emitting layer. When two or more light emitting layers are disposed between the electrodes, the adjacent layer is disposed in contact with at least one of the light emitting layers. The adjacent layer may be disposed between the light emitting layer and the anode and may be in contact with the anode side of the light emitting layer, or may be disposed between the light emitting layer and the cathode and may be in contact with the cathode side of the light emitting layer. . Furthermore, the adjacent layer may be disposed in contact with the anode side and the cathode side of the light emitting layer. The adjacent layer is preferably disposed in contact with the light emitting layer and blocks at least one of holes, electrons, and excitons. For example, when the adjacent layer is disposed in contact with the cathode side of the light emitting layer, the adjacent layer transports electrons, and the holes reach a layer (for example, an electron transport layer) closer to the cathode than the adjacent layer. Stop that. Further, when an adjacent layer is disposed in contact with the anode side of the light-emitting layer, the adjacent layer transports holes, and the electrons reach a layer (for example, a hole transport layer) on the anode side of the adjacent layer. To stop doing. Further, excitons generated in the light emitting layer are prevented from moving to a layer (for example, an electron transport layer or a hole transport layer) closer to the electrode than the adjacent layer.
In the present embodiment, the adjacent layer 6 is preferably adjacent to the cathode 4 side of the light emitting layer 5. Conventionally, materials such as BAlq and BCP have been used for the hole blocking layer. In this embodiment, since the aromatic hydrocarbon compound that is chemically more stable than these compounds is used, the lifetime of the organic EL element can be made longer than before.

The second compound of this embodiment preferably has a condensed ring structure. The condensed ring structure in the second compound may be included in the chemical structural formula as a divalent or higher valent group.
The condensed ring structure in the second compound may have a substituent.

Examples of the substituent of the condensed ring in the second compound include a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, and a substituted or unsubstituted ring formation. Examples thereof include a cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, and a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms.
When the condensed ring in the second compound has a plurality of substituents, the substituents may be combined to form a ring.
Specific examples of the substituent of the condensed ring in the second compound are shown below.

  Examples of the substituted or unsubstituted alkyl group having 1 to 20 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, and n-pentyl. Group, n-hexyl group, n-heptyl group, n-octyl group and the like.

  Examples of the substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms include vinyl group, allyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, 1,3-butanedienyl group, and 1-methylvinyl. Group, styryl group, 2,2-diphenylvinyl group, 1,2-diphenylvinyl group, 1-methylallyl group, 2-methylallyl group, 1-phenylallyl group, 2-phenylallyl group, 3-phenylallyl group, 3 , 3-diphenylallyl group, 1,2-dimethylallyl group, 1-phenyl-1-butenyl group, 3-phenyl-1-butenyl group and the like.

  Examples of the substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a 4-methylcyclohexyl group.

  Examples of the substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms include phenyl group, 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 9-anthryl group, 1- Phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthryl group, 1-naphthacenyl group, 2-naphthacenyl group, 9-naphthacenyl group, 1-pyrenyl group, 2-pyrenyl group, 4- Pyrenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, p-terphenyl-4-yl group, p-terphenyl-3-yl group, p-terphenyl-2-yl group M-terphenyl-4-yl group, m-terphenyl-3-yl group, m-terphenyl-2-yl group, o-tolyl group, m-tolyl group, p-tolyl group , Pt-butylphenyl group, p- (2-phenylpropyl) phenyl group, 3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group, 4-methyl-1-anthryl group, 4′- Examples thereof include a methylbiphenylyl group, 4 ″ -t-butyl-p-terphenyl-4-yl group, and the like.

  Examples of the substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms include benzyl group, 1-phenylethyl group, 2-phenylethyl group, 1-phenylisopropyl group, 2-phenylisopropyl group, 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, 2-β-naphthylisopropyl group, p-methylbenzyl group, m-methylbenzyl group, o-methylbenzyl group and the like.

  The second compound preferably contains a linear, branched or cyclic alkyl group, or a substituted or unsubstituted aromatic hydrocarbon group. When the second compound introduces an aromatic hydrocarbon group as a substituent, it is possible to extend the life of the organic EL device by adjusting the energy gap and preventing molecular association.

  The condensed ring of the second compound is preferably a condensed ring selected from the group consisting of condensed rings represented by the following formulas (S1) to (S13).

(In the formula (S13), R ₃₁ and R ₃₂ are each independently a hydrogen atom or a substituent, and the substituent in R ₃₁ and R ₃₂ is
A substituted or unsubstituted alkyl group having 1 to 20 carbon atoms,
R ₃₁ is a substituent selected from the group consisting of a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms and a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms. And R ₃₂ may be bonded to form a ring. )

  The condensed ring represented by the formulas (S1) to (S13) in the second compound may have a substituent. In this case, the substituent is preferably a linear, branched or cyclic alkyl group, or a substituted or unsubstituted aromatic hydrocarbon group.

  The second compound in the present embodiment is preferably represented by the following general formula (13) or the following general formula (14).

(In the general formula (13) and the general formula (14),
P is a group containing a condensed ring selected from the group consisting of the condensed rings represented by the formulas (S1) to (S13),
Ar ¹ and Ar ² are each independently a group containing a benzene ring, a naphthalene ring, a fluorene ring, or a phenanthrene ring,
x is an integer of 0 or more and 4 or less,
y is an integer of 1 to 4,
When there are a plurality of P, they may be the same or different from each other,
When there are a plurality of Ar ^{1 s} , they may be the same as or different from each other;
When there are a plurality of Ar ^{2 s} , they may be the same or different. )
In the second compound, when there are a plurality of ring structures represented by P, if the ring structure itself is the same structure, the ring structure is the same, and only the position of the bond in the ring structure is different. The ring structure is not different.

  In the general formula (13), for example, when y is 1, the general formula (13) is represented by the following general formula (13-1), and when y is 2, the general formula (13) Is represented by the following general formula (13-2).

Formula (13-1) and the general formula ^{(13-2), P, Ar 1} , Ar 2, x is the respective ^P in the general formula ^{(13), Ar 1, Ar} 2, x synonymous .
Further, for example, in the general formula (13-1), when x is 2, the general formula (13-1) is represented by the following general formula (13-1-1).

In the general formula (13-1-1), ^P, Ar 1, Ar ² has the same meaning defined above ^P in the general formula ^(13), and Ar ^1, Ar ^2, Ar 1 is be the same or different from each other Also good.

When the second compound is represented by the general formula (14), P is a group containing a condensed ring selected from the group consisting of the condensed rings represented by the formulas (S2) to (S13). P may be the same or different from each other, Ar ¹ is a group containing a benzene ring or a naphthalene ring, x is preferably an integer of 1 or more and 3 or less, and when there is a plurality of Ar ¹ , They may be the same or different from each other.

In the second compound, x is preferably 0, 1 or 2.
For example, in the general formula (14), when x is 2, the general formula (14) is represented by the following general formula (14-1-1).

In the general formula (14-1-1), P, Ar ¹ is the same meaning P, a Ar ¹ in the general formula (14), Ar ¹ may be the same or different from each other, P is mutually It may be the same or different.

  In the second compound, the P is preferably a group containing a condensed ring represented by the formula (S10) or the formula (S13).

  In the present embodiment, the second compound having the structure of the formula (S1) is, for example, a naphthalene derivative or a compound represented by the following formula (SA1).

In the formula (SA1), R _{1 to} R ₈ are each independently a hydrogen atom or a substituent, and the substituents in R _{1 to} R ₈ in the formula (SA1) are substituted or unsubstituted rings. A plurality of groups selected from aryl groups having 6 to 30 carbon atoms, branched or straight chain alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 carbon atoms, vinyl groups, and these groups; It is a substituent composed of a combination.
Specific examples of the second compound represented by the formula (SA1) include the following compounds.

  In the present embodiment, the second compound having the structure of the formula (S2) is, for example, a phenanthrene, a phenanthrene derivative, or a compound represented by the following formula (SA2).

In the formula (SA2), R _{1 to} R ₁₀ are each independently a hydrogen atom or a substituent, and the substituent in R _{1 to} R ₁₀ in the formula (SA2) is a substituted or unsubstituted ring. A plurality of groups selected from aryl groups having 6 to 30 carbon atoms, branched or straight chain alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 carbon atoms, vinyl groups, and these groups; It is a substituent composed of a combination.
Specific examples of the second compound represented by the formula (SA2) include the following compounds.

  In the present embodiment, the second compound having the structure of the formula (S3) is, for example, triphenylene, a triphenylene derivative, or a compound represented by the following formula (SA3).

In the formula (SA3), R _{1 to} R ₆ are each independently a hydrogen atom or a substituent, and the substituent in R _{1 to} R ₆ in the formula (SA3) is a substituted or unsubstituted ring. A plurality of groups selected from aryl groups having 6 to 30 carbon atoms, branched or straight chain alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 carbon atoms, vinyl groups, and these groups; It is a substituent composed of a combination.

  Specific examples of the second compound represented by the formula (SA3) include the following compounds.

  In the present embodiment, the second compound having the structure of the formula (S4) is, for example, a benzo [c] phenanthrene, a benzo [c] phenanthrene derivative, or a compound represented by the following formula (SA4).

In the formula (SA4), R _{1 to} R ₁₀ are each independently a hydrogen atom or a substituent, and the substituent in R _{1 to} R ₁₀ in the formula (SA4) is a substituted or unsubstituted ring. A plurality of groups selected from aryl groups having 6 to 30 carbon atoms, branched or straight chain alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 carbon atoms, vinyl groups, and these groups; It is a substituent composed of a combination.
Specific examples of the second compound represented by the formula (SA4) include the following compounds.

  In the present embodiment, the second compound having the structure of the formula (S5) is, for example, chrysene, a chrysene derivative, or a compound represented by the following formula (SA5).

In the formula (SA5), R _{1 to} R ₁₂ are each independently a hydrogen atom or a substituent, and the substituent in R _{1 to} R ₁₂ in the formula (SA5) is a substituted or unsubstituted ring. A plurality of groups selected from aryl groups having 6 to 30 carbon atoms, branched or straight chain alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 carbon atoms, vinyl groups, and these groups; It is a substituent composed of a combination.
Specific examples of the second compound represented by the formula (SA5) include the following compounds.

  In the present embodiment, the second compound having the structure of the formula (S6) is, for example, a benzo [a] triphenylene, a benzo [a] triphenylene derivative, or a compound represented by the following formula (SA6).

In the formula (SA6), R _{1 to} R ₇ are each independently a hydrogen atom or a substituent, and the substituent in R _{1 to} R ₇ in the formula (SA6) is a substituted or unsubstituted ring. A plurality of groups selected from aryl groups having 6 to 30 carbon atoms, branched or straight chain alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 carbon atoms, vinyl groups, and these groups; It is a substituent composed of a combination.

  Specific examples of the second compound represented by the formula (SA6) include the following compounds.

  In the present embodiment, the second compound having the structure of the formula (S7) is, for example, a benzo [a] chrysene, a benzo [a] chrysene derivative, or a compound represented by the following formula (SA7).

In the formula (SA7), R _{1 to} R ₁₂ are each independently a hydrogen atom or a substituent, and the substituent in R _{1 to} R ₁₂ in the formula (SA7) is a substituted or unsubstituted ring. A plurality of groups selected from aryl groups having 6 to 30 carbon atoms, branched or straight chain alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 carbon atoms, vinyl groups, and these groups; It is a substituent composed of a combination.
Specific examples of the second compound represented by the formula (SA7) include the following compounds.

  In the present embodiment, the second compound having the structure of the formula (S8) is, for example, a benzo [c] chrysene, a benzo [c] chrysene derivative, or a compound represented by the following formula (SA8).

In the formula (SA8), R _{1 to} R ₁₂ are each independently a hydrogen atom or a substituent, and the substituent in R _{1 to} R ₁₂ in the formula (SA8) is a substituted or unsubstituted ring. A plurality of groups selected from aryl groups having 6 to 30 carbon atoms, branched or straight chain alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 carbon atoms, vinyl groups, and these groups; It is a substituent composed of a combination.
Specific examples of the second compound represented by the formula (SA8) include the following compounds.

  In the present embodiment, the second compound having the structure of the formula (S9) is, for example, acenaphthylene, an acenaphthylene derivative, or a compound represented by the following formula (SA9).

In the formula (SA9), R _{1 to} R ₈ are each independently a hydrogen atom or a substituent, and the substituent in R _{1 to} R ₈ in the formula (SA9) is a substituted or unsubstituted ring. A plurality of groups selected from aryl groups having 6 to 30 carbon atoms, branched or straight chain alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 carbon atoms, vinyl groups, and these groups; It is a substituent composed of a combination.

  Specific examples of the second compound represented by the formula (SA9) include the following compounds.

  In the present embodiment, the second compound having the structure of the formula (S10) is, for example, a fluoranthene, a fluoranthene derivative, or a compound represented by the following formula (SA10).

In the formula (SA10), R _{1 to} R ₁₀ are each independently a hydrogen atom or a substituent, and the substituent in R _{1 to} R ₁₀ in the formula (SA10) is a substituted or unsubstituted ring. A plurality of groups selected from aryl groups having 6 to 30 carbon atoms, branched or straight chain alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 carbon atoms, vinyl groups, and these groups; It is a substituent composed of a combination.

  Specific examples of the second compound represented by the formula (SA10) include the following compounds.

  In the present embodiment, the second compound having the structure of the formula (S11) is, for example, a benzo [k] fluoranthene, a benzo [k] fluoranthene derivative, or a compound represented by the following formula (SA11).

In the formula (SA11), R _{1 to} R ₁₂ are each independently a hydrogen atom or a substituent, and the substituent in R _{1 to} R ₁₂ in the formula (SA11) is a substituted or unsubstituted ring. A plurality of groups selected from aryl groups having 6 to 30 carbon atoms, branched or straight chain alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 carbon atoms, vinyl groups, and these groups; It is a substituent composed of a combination.

  Specific examples of the second compound represented by the formula (SA11) include the following compounds.

  In the present embodiment, the second compound having the structure of the formula (S12) is, for example, a benzo [b] fluoranthene, a benzo [b] fluoranthene derivative, or a compound represented by the following formula (SA12).

In the formula (SA12), R _{1 to} R ₁₂ are each independently a hydrogen atom or a substituent, and the substituents in R _{1 to} R ₁₂ in the formula (SA12) are substituted or unsubstituted rings. A plurality of groups selected from aryl groups having 6 to 30 carbon atoms, branched or straight chain alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 carbon atoms, vinyl groups, and these groups; It is a substituent composed of a combination.

  Specific examples of the second compound represented by the formula (SA12) include the following compounds.

Formula (SA10) _R 1 _{~R 10} in, as _R 1 _{to R 12} and linear in _R 1 _{to R 12} of said formula (SA12) in, branched or cyclic alkyl group, of the formula (SA11) in Is, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl. Group, cyclopentyl group, n-hexyl group, 3,3-dimethylbutyl group, cyclohexyl group, n-heptyl group, cyclohexylmethyl group, n-octyl group, tert-octyl group, 2-ethylhexyl group, n-nonyl group, An n-decyl group, an n-dodecyl group, an n-tetradecyl group, an n-hexadecyl group, and the like can be given as examples of the aryl group. For example, phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-n-propylphenyl group, 4-isopropylphenyl group, 4-n-butylphenyl Group, 4-tert-butylphenyl group, 4-isopentylphenyl group, 4-tert-pentylphenyl group, 4-n-hexylphenyl group, 4-cyclohexylphenyl group, 4-n-octylphenyl group, 4-n -Decylphenyl group, 2,3-dimethylphenyl group, 2,4-dimethylphenyl group, 2,5-dimethylphenyl group, 3,4-dimethylphenyl group, 5-indanyl group, 1,2,3,4- Tetrahydro-5-naphthyl group, 1,2,3,4-tetrahydro-6-naphthyl group, 4-phenylphenyl group, 3-phenylphenyl group 4- (4′-methylphenyl) phenyl group, 1-naphthyl group, 2-naphthyl group and the like.
_R 1 _{to R 10} in the formula (SA10), _R 1 _{~R 12} of the formula (SA11) in, as well as _R 1 _{to R 12} in the formula (SA12) is preferably a hydrogen atom, the number of carbon atoms It is a 1-10 alkyl group or a C6-C12 aryl group, More preferably, they are a hydrogen atom, a C1-C6 alkyl group, or a C6-C10 aryl group.

  In the present embodiment, the second compound having the structure of the formula (S13) is, for example, fluorene, a fluorene derivative, or a compound represented by the following formula (SA13).

In the formula (SA13), R _{1 to} R ₈ are each independently a hydrogen atom or a substituent, and the substituent in R _{1 to} R ₈ in the formula (SA13) is a substituted or unsubstituted ring. A plurality of groups selected from aryl groups having 6 to 30 carbon atoms, branched or straight chain alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 carbon atoms, vinyl groups, and these groups; It is a substituent composed of a combination.
In the formula (SA13), R ₃₁ and R ₃₂ are each independently a hydrogen atom or a substituent, and the substituent in R ₃₁ and R ₃₂ is
A substituted or unsubstituted alkyl group having 1 to 20 carbon atoms,
It is a substituent selected from the group consisting of a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms and a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms.

  Specific examples of the second compound represented by the formula (SA13) include the following compounds.

(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 is made of, for example, polycarbonate, polyarylate, polyethersulfone, polypropylene, polyester, polyvinyl fluoride, polyvinyl chloride, polyimide, or polyethylene naphthalate. Examples include a plastic substrate. 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- Aromatic amine compounds such as [N- (1-naphthyl) -N- (9-phenylcarbazol-3-yl) amino] -9-phenylcarbazole (abbreviation: PCzPCN1), and dipyrazino [2,3-f: 20 , 30-h] quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN).
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, CBP, 9- [4- (N-carbazolyl)] phenyl-10-phenylanthracene (CzPA), 9-phenyl-3- [4- (10-phenyl-9-anthryl) phenyl] A carbazole derivative such as -9H-carbazole (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.
When two or more hole transport layers are arranged, it is preferable to arrange a material having a larger energy gap on the side closer to the light emitting layer. An example of such a material is HT-2 used in Examples described later. And it is preferable to arrange | position a non-amine type compound as an adjacent layer of a light emitting layer. Examples of such a material include the second compound of the present embodiment. Further, when the second compound of the present embodiment is arranged in the adjacent layer on the cathode side, a compound having a large energy gap such as CBP can be arranged in the adjacent layer on the anode side.

(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. In this embodiment, a benzimidazole compound can be suitably 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 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, for example, when a fluorene ring is bonded to the fluorene ring as a substituent (including a spirofluorene ring), the carbon number of the fluorene ring as a substituent is not included in the number of ring-forming carbons. In this specification, the number of ring-forming atoms means a compound (for example, a monocyclic compound, a condensed ring compound, a bridging compound, a carbocyclic compound, a heterocyclic compound) having a structure in which atoms are bonded in a cyclic manner (for example, a monocyclic ring, a condensed ring, or a ring assembly). Of the ring compound) represents the number of atoms constituting the ring itself. An atom that does not constitute a ring (for example, a hydrogen atom that terminates a bond of an atom that constitutes a ring) or an atom contained in a substituent when the ring is substituted by a substituent is not included in the number of ring-forming atoms. 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 spirofluorene 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 aromatic hydrocarbon group having 6 to 30 ring carbon atoms (aryl group) in the present embodiment include a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, an anthryl group, a phenanthryl group, a fluorenyl group, and a 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 [b] triphenylenyl group, picenyl Group, 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 9-position carbon atom is substituted with a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms in the present embodiment described later. It is preferable that

Examples of the heterocyclic group having 5 to 30 ring atoms (heteroaryl group) in the present embodiment include a pyridyl group, pyrimidinyl group, pyrazinyl group, pyridazinyl group, triazinyl group, quinolyl group, isoquinolinyl group, naphthyridinyl group, and phthalazinyl. Group, 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, imidazolpyridyl group Zinyl, benztriazolyl, carbazolyl, furyl, thienyl, oxazolyl, thiazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, thiadiazolyl, benzofuranyl, benzothiophenyl , Benzoxazolyl group, benzothiazolyl group, benzisoxazolyl group, benzisothiazolyl 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 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 invention, “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 invention, the hydrogen atom includes isotopes having different numbers of neutrons, that is, light hydrogen (Protium), deuterium (Deuterium), and tritium (Tritium).

In addition, examples of the substituent in the present embodiment such as a substituent in the case of “substituted or unsubstituted”, a ring structure A, a ring structure B, a ring structure E, a ring structure F, a substituent in the ring structure G, etc. Aryl group, heterocyclic group, alkyl group (straight chain or branched chain alkyl group, cycloalkyl group, haloalkyl group), alkylsilyl group, arylsilyl group, alkoxy group, aryloxy group, alkylamino group, arylamino In addition to groups, alkylthio groups, and arylthio groups, alkenyl groups, alkynyl groups, aralkyl groups, halogen atoms, cyano groups, hydroxyl groups, nitro groups, and carboxy groups are exemplified.
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, and further, specific examples that are preferable in the description of each substituent Are preferred.
These substituents may be further substituted with the above substituents. A plurality of these substituents may be bonded to each other to form a ring.

  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 carbon atoms, preferably 6 to 20 carbon atoms, more preferably 6 to 12 carbon atoms), and the alkyl moiety is 1 to 30 carbon atoms (preferably 1 to 1 carbon atoms). 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 a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.

The term “unsubstituted” in the case of “substituted or unsubstituted” means that a hydrogen atom is bonded without being substituted with the substituent.
In the present specification, “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. The carbon number of the substituent when substituted is not included. Here, “YY” is larger than “XX”, and “XX” and “YY” each mean an integer of 1 or more.
In the present specification, “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, a multiple linking group in which 2 to 4 groups selected from the aromatic hydrocarbon group are bonded, and a multiple in which 2 to 4 groups selected from the heterocyclic group are bonded. Examples of a linking group or a multiple linking group formed by bonding two to four groups selected from the aromatic hydrocarbon group and the heterocyclic group include the aromatic hydrocarbon group and the heterocyclic group. Examples thereof include a divalent group formed by bonding 2 to 4 groups selected. Examples of the multiple linking group formed by bonding 2 to 4 groups selected from the aromatic hydrocarbon group and the heterocyclic group include heterocyclic group-aromatic hydrocarbon group, aromatic hydrocarbon group-heterocycle Group, aromatic hydrocarbon group-heterocyclic group-aromatic hydrocarbon group, heterocyclic group-aromatic hydrocarbon group-heterocyclic group, aromatic hydrocarbon group-heterocyclic group-aromatic hydrocarbon group-heterocycle Group, heterocyclic group-aromatic hydrocarbon group-heterocyclic group-aromatic hydrocarbon group, and the like. Preferably, a divalent group formed by bonding the aromatic hydrocarbon group and the heterocyclic group one by one, that is, a heterocyclic group-aromatic hydrocarbon group, and an aromatic hydrocarbon group-heterocyclic group. . Specific examples of the aromatic hydrocarbon group and the heterocyclic group in these multiple linking groups include the groups described above for the aromatic hydrocarbon group and the heterocyclic group.

[Second Embodiment]
As shown in FIG. 5, the organic EL element 1 </ b> A according to the second embodiment of the present invention is disposed in contact with the adjacent layer 6 on the anode 3 side of the light emitting layer 5.
In other respects, the organic EL element 1A is configured in the same manner as the organic EL element 1 according to the first embodiment.
In the second embodiment, since the second compound is an aromatic hydrocarbon compound having no hetero atom, it is a chemically or photo / electrochemically strong material. As a result, according to the organic EL element 1 </ b> A of the present embodiment that contains the second compound in the adjacent layer 6, the lifetime can be extended. Further, when the light emitting position in the light emitting layer 5 is biased toward the anode 3, the effect of extending the life is great.

[Third embodiment]
As shown in FIG. 6, the organic EL element 1 </ b> B according to the third embodiment of the present invention is provided with the first adjacent layer 6 </ b> A in contact with the light emitting layer 5 on the cathode 4 side of the light emitting layer 5. The second adjacent layer 6B is further disposed in contact with the light emitting layer 5 on the anode 3 side.
6 A of 1st adjacent layers are comprised similarly to the adjacent layer 6 in 1st embodiment. The second adjacent layer 6B may be made of the same material as that of the adjacent layer 6, or a compound having a carbazolyl group that can be used as the third compound described in the first embodiment (for example, CBP, mCP, etc. ).
In other respects, the organic EL element 1B is configured in the same manner as the organic EL element 1 according to the first embodiment.
In the third embodiment, since the second compound contained in the first adjacent layer 6A is an aromatic hydrocarbon compound having no hetero atom, it is a chemically or optically / chemically strong material. . As a result, according to the organic EL element 1 </ b> B of the present embodiment that contains the second compound in the adjacent layer 6, the lifetime can be extended.
When the thickness of the light-emitting layer 5 is thin (for example, 10 nm or less), the excitons of the first material tend to affect the layer in contact with the anode 3 side and the cathode 4 side of the light-emitting layer 5, thereby extending the life. The effect is great.

[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 contains a compound represented by the general formula (1), and the other light emitting layers are fluorescent light emitting layers. Alternatively, it may be a phosphorescent light-emitting layer that utilizes light emission by electron transition from a triplet excited state to a direct ground state.
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.

  An organic EL element according to an embodiment of the present invention is a display component such as an organic EL panel module, a display device such as a television, a mobile phone, a tablet or a personal computer, and an electronic device such as a light emitting device for lighting or a vehicle lamp. Can be used for

  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 as follows.

<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.

・ Singlet energy EgS
A 10 μmol / L toluene solution of Compound TD-1 was prepared and placed in a quartz cell, and the emission spectrum (vertical axis: emission intensity, horizontal axis: wavelength) of this sample was measured at room temperature (300 K). A single line energy was calculated by drawing a tangent line from the short wavelength side rise of the emission spectrum and substituting the wavelength value λ _edge [nm] at the intersection of the tangent line and the horizontal axis into the following conversion formula 2.
Conversion formula 2: EgS [eV] = 1239.85 / λ _edge
In this example, the emission spectrum was measured with a spectrophotometer manufactured by Hitachi (device name: U3310).

A tangent to the rising edge of the emission spectrum on the short wavelength side was 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) was taken as the tangent to the rise on the short wavelength side of the emission spectrum.
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 was taken was taken as the tangent to the rise of the emission spectrum on the short wavelength side.

-Delayed fluorescence emission Delayed fluorescence emission was confirmed by measuring transient PL using the apparatus shown in FIG. Compound TD-1 and compound TH-2 were co-evaporated on a quartz substrate so that the ratio of compound TD-1 was 12% by mass, and a thin film having a thickness of 100 nm was formed to prepare a sample.
When this sample was irradiated with pulsed excitation light using a pulse laser generator (LTB LASERTECHNIK BERLIN MNL200) at room temperature, light emission from the compound TD-1 was observed. The light emitted from Compound TD-1 is dispersed with a spectroscope, a two-dimensional image is formed using a streak camera (C4344, manufactured by Hamamatsu Photonics), analyzed by a personal computer, and the emission intensity after light irradiation is measured. The change with time (transient PL spectrum) was measured. The value obtained by integrating the emission intensity of light emission after 1 microsecond (Delay light emission) after light irradiation in the transient PL spectrum with respect to time is obtained by integrating the light emission intensity of light emission within 1 microsecond (Promp light emission) with respect to time. Since it was 5% or more of the value, it was confirmed that Compound TD-1 exhibited delayed fluorescence.

・ Energy gap Eg _77K
A measurement sample was prepared as follows.
For compounds other than compound TD-1, the concentration of the compound to be measured is 10 μmol / L in EPA (diethyl ether: isopentane: ethanol = 5: 5: 2 (volume ratio)) as a solvent. It melt | dissolved, this solution was put in the quartz cell, and it was set as the measurement sample.
Since compound TD-1 exhibited delayed fluorescence as described above, the measurement sample was changed. Specifically, compound TD-1 and compound TH-2 are co-evaporated on a quartz substrate so that the ratio of compound TD-1 is 12% by mass to form a thin film having a thickness of 100 nm, and a measurement sample It was.
With respect to these measurement samples, phosphorescence spectrum (vertical axis: phosphorescence emission intensity, horizontal axis: wavelength) is measured at a low temperature (77 [K]), and a tangent line is formed with respect to the rising edge of the phosphorescence spectrum on the short wavelength side. The energy amount calculated from the following conversion formula 1 based on the wavelength value λ _edge [nm] of the intersection of the tangent line and the horizontal axis was defined as an energy gap Eg _77K .
Conversion formula 1: Eg _77K [eV] = 1239.85 / λ _edge
The tangent to the rising edge on the short wavelength side of the phosphorescence spectrum was drawn as described above. For measurement of phosphorescence, an F-4500 spectrofluorometer main body manufactured by Hitachi High-Technology Co., Ltd. was used.

・ ΔST
It was 0.16 [eV] as a result of calculating | requiring (DELTA) ST of compound TD-1 as a difference of EgS measured by the above-mentioned method, and Eg _77K .

・ Ionization potential Ip
Measurement was performed using a photoelectron spectrometer (Riken Keiki Co., Ltd .: AC-3) under the atmosphere. Specifically, the measurement was performed by irradiating the compound to be measured with light and measuring the amount of electrons generated by charge separation.

<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 first, the compound HI is deposited so as to cover the transparent electrode on the surface where the transparent electrode line is formed, and the film thickness is 5 nm. The hole injection layer was formed.
Next, Compound HT-1 was vapor-deposited on the hole injection layer, and a first hole transport layer having a thickness of 20 nm was formed on the HI film.
Next, Compound HT-2 was vapor-deposited on the first hole transport layer to form a second hole transport layer having a thickness of 5 nm.
Next, a compound CBP was vapor-deposited on the second hole transport layer to form a third hole transport layer having a thickness of 5 nm.
Further, a compound TH-1 as the third compound and a compound TD-1 as the first compound were co-evaporated on the third hole transport layer to form a light emitting layer having a thickness of 25 nm. The mass ratio of compound TH-1 to compound TD-1 was 1: 1.
Next, on this light emitting layer, the compound HB-1 as a 2nd compound was vapor-deposited, and the adjacent layer with a film thickness of 5 nm was formed.
Next, Compound ET-1 was vapor-deposited on this adjacent layer to form an electron transport layer having a thickness of 50 nm.
Next, lithium fluoride (LiF) was vapor-deposited on the electron transport layer to form an electron injecting electrode (cathode) having a thickness of 1 nm.
And metal aluminum (Al) was vapor-deposited on this electron injecting electrode, and the metal Al cathode with a film thickness of 80 nm was formed.
A device arrangement of the organic EL device of Example 1 is schematically shown as follows.
ITO (130) / HI (5) / HT-1 (20) / HT-2 (5) / CBP (5) / TH-1: TD-1 (25, 50%) / HB-1 (5) / ET-1 (50) / LiF (1) / Al (80)
The numbers in parentheses indicate the film thickness (unit: nm). Similarly, in the parentheses, the number displayed as a percentage indicates the ratio (mass%) of a component to be added, such as a dopant material in the light emitting layer.

(Reference Example 1)
The organic EL device of Reference Example 1 was produced in the same manner as in Example 1 except that the compound in the adjacent layer in Example 1 was changed from HB-1 to HB-2.
The device configuration of the organic EL device of Reference Example 1 is schematically shown as follows.
ITO (130) / HI (5) / HT-1 (20) / HT-2 (5) / CBP (5) / TH-1: TD-1 (25, 50%) / HB-2 (5) / ET-1 (50) / LiF (1) / Al (80)

(Reference Example 2)
The organic EL device of Reference Example 2 was produced in the same manner as in Example 1 except that the compound in the adjacent layer in Example 1 was changed from HB-1 to HB-3.
The element configuration of the organic EL element of Reference Example 2 is schematically shown as follows.
ITO (130) / HI (5) / HT-1 (20) / HT-2 (5) / CBP (5) / TH-1: TD-1 (25, 50%) / HB-3 (5) / ET-1 (50) / LiF (1) / Al (80)

(Reference Example 3)
The organic EL device of Reference Example 3 was produced in the same manner as in Example 1 except that the compound in the adjacent layer in Example 1 was changed from HB-1 to HB-4.
A device arrangement of the organic EL device of Reference Example 3 is schematically shown as follows.
ITO (130) / HI (5) / HT-1 (20) / HT-2 (5) / CBP (5) / TH-1: TD-1 (25, 50%) / HB-4 (5) / ET-1 (50) / LiF (1) / Al (80)

[Evaluation of organic EL elements]
The following evaluation was performed about the organic EL element produced in Example 1 and Reference Examples 1-3. The evaluation results are shown in Table 6.

-Driving voltage The voltage (unit: V) when electricity was passed between the ITO electrode and the metal Al cathode so that the current density was 10.0 mA / cm ² was measured.

・ Current efficiency L / J
Spectral radiance spectrum when a voltage is applied to the organic EL element so that the current density is 10.0 mA / cm ² is measured with a spectral radiance meter CS-1000 (manufactured by Konica Minolta), and the obtained spectral radiation The current efficiency L / J (unit: cd / A) was calculated from the luminance spectrum.

Lifetime A voltage was applied to the organic EL element so that the current density was 50.00 mA / cm ^2, and the time until the luminance became 80% of the initial luminance (unit: h) was measured. The life is a value (relative value) obtained by calculating the ratio of the life time of Example 1 and Reference Examples 1 to 3 to the life time of Example 1.

As shown in Table 6, the organic EL device of Example 1 includes an adjacent layer containing Compound HB-1 as the second compound on the cathode side of the light emitting layer containing Compound TD-1. As a result, the lifetime was 30 to 43% longer than that of the organic EL elements of Reference Examples 1 to 3.
In the devices of Reference Examples 1 to 3, the adjacent layer provided on the cathode side of the light emitting layer contains a compound containing a nitrogen atom which is a hetero atom. Therefore, although the driving voltage and current efficiency were comparable, the lifetime was shortened compared with the organic EL element of Example 1.

DESCRIPTION OF SYMBOLS 1,1A, 1B ... Organic EL element 2 ... Substrate 3 ... Anode 4 ... Cathode 5 ... Light emitting layer 6, 6A, 6B ... Adjacent layer 7 ... Hole injection / transport layer 8 ... Electron injection / transport layer 10 ... Organic layer

Claims (22)

The anode,
A cathode,
A light emitting layer;
An adjacent layer adjacent to the light emitting layer,
The light emitting layer contains a first compound exhibiting thermally activated delayed fluorescence,
The adjacent layer contains a second compound that is an aromatic hydrocarbon compound;
The second compound does not contain a heteroatom ,
Having the adjacent layer between the light emitting layer and the cathode;
An organic electroluminescence device comprising an electron transport layer between the adjacent layer and the cathode . The organic electroluminescent device according to claim 1,
Said 2nd compound has condensed ring structure. The organic electroluminescent element characterized by the above-mentioned. The organic electroluminescence device according to claim 2,
The condensed ring structure is a condensed ring structure selected from the group consisting of condensed ring structures represented by the following formulas (S1) to (S13). An organic electroluminescence device, wherein:
(In the formula (S13), R ₃₁ and R ₃₂ are each independently a hydrogen atom or a substituent, and the substituent in R ₃₁ and R ₃₂ is
A substituted or unsubstituted alkyl group having 1 to 20 carbon atoms,
R ₃₁ is a substituent selected from the group consisting of a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms and a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms. And R ₃₂ may be bonded to form a ring. ) In the organic electroluminescent element according to claim 3,
Said 2nd compound is represented by following General formula (13) or following General formula (14). The organic electroluminescent element characterized by the above-mentioned.
(In the general formula (13) and the general formula (14),
P is a group containing a condensed ring selected from the group consisting of the condensed rings represented by the formulas (S1) to (S13),
Ar ¹ and Ar ² are each independently a group containing a benzene ring, a naphthalene ring, a fluorene ring, or a phenanthrene ring,
x is an integer of 0 or more and 4 or less,
y is an integer of 1 to 4,
When there are a plurality of P, they may be the same or different from each other,
When there are a plurality of Ar ^{1 s} , they may be the same as or different from each other;
When there are a plurality of Ar ^{2 s} , they may be the same or different. ) In the organic electroluminescent element according to claim 4,
When the second compound is represented by the general formula (14),
P is a group containing a condensed ring selected from the group consisting of the condensed rings represented by the formulas (S2) to (S13), and P may be the same as or different from each other;
Ar ¹ is a group containing a benzene ring or a naphthalene ring,
x is an integer of 1 to 3,
When there are a plurality of Ar ^{1 s} , they may be the same as or different from each other. In the organic electroluminescent element according to claim 4 or 5,
x is 2, the organic electroluminescent element characterized by the above-mentioned. In the organic electroluminescent element according to any one of claims 4 to 6,
P is a group containing a condensed ring represented by the formula (S10) or the formula (S13). An organic electroluminescence element, In the organic electroluminescent element according to any one of claims 4 to 7,
Said 2nd compound is represented by the said General formula (14). The organic electroluminescent element characterized by the above-mentioned. In the organic electroluminescent element according to any one of claims 1 to 8,
The difference ΔST (M1) between the singlet energy EgS (M1) of the first compound and the energy gap Eg _77K (M1) at 77 [K] of the first compound is expressed by the following equation (Equation 1). An organic electroluminescence element characterized by satisfying
ΔST (M1) = EgS (M1) −Eg _77K (M1) <0.3 [eV] (Equation 1) In the organic electroluminescent element according to any one of claims 1 to 9,
The first compound includes a partial structure represented by the following general formula (2) and a partial structure represented by the following general formula (3) in one molecule.
(In the general formula (2), 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 first compound. The 6-membered ring structure represented by the general formula (2) may construct a ring structure at an arbitrary position. )
(In the general formula (3), F and G each independently represent a ring structure.
m is 0 or 1.
When m is 1, Y ₂₀ represents a single bond, an oxygen atom, a sulfur atom, a selenium atom, a carbon atom, a silicon atom, or a germanium atom. ) In the organic electroluminescent element according to claim 10,
The general formula (3) is represented by at least one of the following general formula (3a) and the following general formula (3b). An organic electroluminescent element.
(In the general formula (3b), E represents a ring structure represented by the following general formula (3c) or a ring structure represented by the following general formula (3d), and this ring structure E represents an adjacent ring. 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 (3d), Z ₇ represents a carbon atom, a nitrogen atom, a sulfur atom, or an oxygen atom.) The organic electroluminescence device according to claim 10 or 11,
Said 1st compound 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 (2), provided that in the general formula (2), 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 a hydrogen atom or a substituent, and the substituent in R is
A halogen 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 substituent selected from the group consisting of a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms and a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms;
D is represented by the general formula (3), provided that the ring structure F and the ring structure G in the general formula (3) may be unsubstituted or have a substituent,
m is 0 or 1,
When m is 1, Y ₂₀ 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 represent , Are the same as the groups listed for 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 A 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 , a substituted or unsubstituted aliphatic hydrocarbon ring group, or A substituted or unsubstituted aliphatic heterocyclic group, and each of R _{81 to} R ₉₁ independently has the same meaning as the group listed for R;
(Ii) when located at the terminal in the molecule of the first compound, it is synonymous with the group exemplified in the 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 12,
The light emitting layer further contains a third compound that is an organic compound,
The organic electroluminescence device characterized in that an energy gap Eg _77K (M3) at 77 [K] of the third compound is larger than an energy gap Eg _77K (M1) at 77 [K] of the first compound. . The organic electroluminescence device according to claim 13,
The third compound is at least one compound selected from the group consisting of a compound having a triphenylene ring, a compound having a dibenzofuran ring, a compound having a dibenzothiophene ring, a silicon-containing aromatic compound, and a phosphorus-containing aromatic compound. An organic electroluminescence device characterized by the following. The organic electroluminescence device according to claim 13,
Said 3rd compound is a compound which has a triphenylene ring. The organic electroluminescent element characterized by the above-mentioned. The organic electroluminescence device according to claim 13,
Said 3rd compound is represented by following General formula (40). The organic electroluminescent element characterized by the above-mentioned.
(In the general formula (40),
X ^{1 to} X ¹² are each independently a nitrogen atom or C—R ^A ,
Each R ^A is independently a hydrogen atom or a substituent, and the substituent in this R ^A is
A halogen atom,
A cyano group,
A substituted or unsubstituted alkyl group having 1 to 20 carbon atoms,
A substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms,
A substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms,
A substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms,
A substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms,
A substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms,
A substituted or unsubstituted alkylsilyl group having 3 to 50 carbon atoms,
A substituted or unsubstituted arylsilyl group having 6 to 50 ring carbon atoms,
It is a substituent selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms and a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms. ) The organic electroluminescence device according to claim 16,
In the general formula (40), at least one of X ^{1 to} X ¹² is C—R ^A ,
At least 1 of ^RA is represented by the following general formula (1b), The organic electroluminescent element characterized by the above-mentioned.
(In the general formula (1b),
r is an integer of 0 to 5,
Ar ^a is a substituted or unsubstituted arylene group having 6 to 15 ring carbon atoms or a substituted or unsubstituted heteroarylene group having 5 to 15 ring atoms, and when ^a plurality of Ar ^a are present, they are the same as each other But it can be different,
Ar ^b is a substituted or unsubstituted aryl group having 6 to 20 ring carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 20 ring atoms. ) In the organic electroluminescent element according to any one of claims 1 to 17 ,
The organic light-emitting device, wherein the light-emitting layer does not contain a metal complex. In the organic electroluminescent element according to any one of claims 1 to 18 ,
In the light emission observed after being excited by pulsed light having a wavelength that is absorbed by the first compound, the first compound is observed within 1 μsec from the excitation, and from 1 μsec after the excitation. An organic electroluminescence device characterized by exhibiting light emission observed at a later time. The organic electroluminescence device according to claim 19 ,
The amount of luminescence observed in a time later than 1 μsec after the excitation is 5% or more of the amount of luminescence observed within 1 μsec from the excitation. In the organic electroluminescent element according to any one of claims 1 to 20 ,
The adjacent layer is composed only of a compound not containing a hetero atom, and is an organic electroluminescence element. The electronic device provided with the organic electroluminescent element as described in any one of Claim 1- Claim 21 .