Organic electroluminescent element
An organic EL device includes a pair of electrodes and an organic compound layer between pair of electrodes. The organic compound layer includes an emitting layer including a first material, a second material and a third material, in which singlet energy EgS(H) of the first material, singlet energy EgS(H2) of the second material, and singlet energy EgS(D) of the third material satisfy a specific relationship.
1. An organic electroluminescence device comprising a pair of electrodes and an organic compound layer therebetween, the organic compound layer comprising an emitting layer comprising: a first material; a second material; and a third material, wherein
singlet energy EgS(H1) of the first material, singlet energy EgS(H2) of the second material, and singlet energy EgS(D) of the third material satisfy a relationship of numerical formulae (1) and (2) below,
a difference ΔST(H1) between the singlet energy EgS(H1) of the first material and an energy gap Eg 77K (H1) at 77K of the first material satisfies a relationship of a numerical formula (3) below,
the energy gap Eg 77K (H1) at 77K of the first material is greater than an energy gap Eg 77K (D) at 77K of the third material, and
the third material is a fluorescent material,
EgS ( H 1)> EgS ( D ) (1)
EgS ( H 2)> EgS ( D ) (2)
Δ ST ( H 1)= EgS ( H 1)− Eg 77K ( H 1)<0.3[eV] (3).
2. The organic electroluminescence device according to claim 1 , wherein
the difference ΔST(H1) between the singlet energy EgS(H1) of the first material and the energy gap Eg 77K (H1) at 77K of the first material satisfies a relationship of a numerical formula (4) below,
Δ ST ( H 1)= EgS ( H 1)− Eg 77K ( H 1)<0.2[eV] (4).
3. The organic electroluminescence device according to claim 1 , wherein
an energy gap Eg 77K (H2) at 77K of the second material and the energy gap Eg 77K (D) at 77K of the third material satisfy a relationship of a numerical formula (5) below,
Eg 77K ( H 2)< Eg 77K ( D ) (5).
4. The organic electroluminescence device according to claim 1 , wherein
the energy gap Eg 77K (H1) at 77K of the first material and the energy gap Eg 77K (H2) at 77K of the second material satisfy a relationship of a numerical formula (6) below,
Eg 77K ( H 1)− Eg 77K ( H 2)>0.5[eV] (6).
5. The organic electroluminescence device according to claim 1 , wherein
the energy gap Eg 77K (H1) at 77K of the first material and the energy gap Eg 77K (D) at 77K of the third material satisfy a relationship of a numerical formula (7) below,
Eg 77K ( H 1)− Eg 77K ( D )>0.5[eV] (7).
6. The organic electroluminescence device according to claim 1 , wherein
the organic electroluminescence device exhibits a delayed fluorescence ratio larger than 37.5%.
7. The organic electroluminescence device according to claim 1 , wherein
the organic electroluminescence device exhibits a residual intensity ratio larger than 36.0% after an elapse of 1 μs after voltage removal in a transitional EL measurement.
8. The organic electroluminescence device according to claim 1 , wherein
a half bandwidth of a photoluminescence spectrum of the first material is 50 nm or more.
9. The organic electroluminescence device according to claim 1 , wherein
an emission peak wavelength of the third material is in a range of 500 nm to 600 nm.
10. The organic electroluminescence device according to claim 1 , wherein the emitting layer does not comprise a heavy-metal complex.
11. The organic electroluminescence device according to claim 1 , wherein the first material exhibits a delayed fluorescence.
12. The organic electroluminescence device according to claim 2 , wherein a half bandwidth of a photoluminescence spectrum of the first material is 50 nm or more, and the emitting layer does not comprise a heavy-metal complex.
13. The organic electroluminescence device according to claim 2 , wherein a half bandwidth of a photoluminescence spectrum of the first material is 50 nm or more, and the first material exhibits a delayed fluorescence.
14. The organic electroluminescence device according to claim 2 , wherein the emitting layer does not comprise a heavy-metal complex, and the first material exhibits a delayed fluorescence.
15. The organic electroluminescence device according to claim 2 , wherein a half bandwidth of a photoluminescence spectrum of the first material is 50 nm or more, the emitting layer does not comprise a heavy-metal complex, and the first material exhibits a delayed fluorescence.
16. An organic electroluminescence device comprising a pair of electrodes and an organic compound layer therebetween, the organic compound layer comprising an emitting layer comprising: a first material; a second material; and a third material, wherein
singlet energy EgS(H1) of the first material, singlet energy EgS(H2) of the second material, and singlet energy EgS(D) of the third material satisfy a relationship of numerical formulae (1) and (2) below,
a difference ΔST(H1) between the singlet energy EgS(H1) of the first material and an energy gap Eg 77K (H1) at 77K of the first material satisfies a relationship of a numerical formula (3) below,
the energy gap Eg 77K (H1) at 77K of the first material is greater than an energy gap Eg 77K (D) at 77K of the third material, and
the third material is a fluorescent material,
EgS ( H 1)> EgS ( D ) (1)
EgS ( H 2)> EgS ( D ) (2)
Δ ST ( H 1)= EgS ( H 1)− Eg 77K ( H 1)<0.3[eV] (3).
wherein the first material is represented by a formula (101) below,
A 1 and A 2 independently represent:
a hydrogen atom;
a halogen atom;
a cyano group;
a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms;
a substituted or unsubstituted aromatic heterocyclic group having 2 to 30 ring carbon atoms;
a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms;
a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms;
a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms;
a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms;
a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms; or
a substituted or unsubstituted silyl group,
Y 1 to Y 4 and Y 13 to Y 16 each independently represent C(R) or a nitrogen atom,
Y 5 to Y 8 each independently represent C(R), a nitrogen atom or a carbon atom bonded to one of Y 9 to Y 12 ,
Y 9 , to Y 12 , each independently represent C(R), a nitrogen atom or a carbon atom bonded to one of Y 5 to Y 8 ,
R independently represents a hydrogen atom or a substituent, the substituent for R being the same as the substituent for A 1 and A 2 , and
L 1 and L 2 each independently represent: a single bond; a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 30 ring carbon atoms; a substituted or unsubstituted divalent aromatic heterocyclic group having 2 to 30 ring carbon atoms; or a group formed by bonding the above divalent aromatic hydrocarbon group and the above divalent aromatic heterocyclic group.
17. The organic electroluminescence device according to claim 16 , wherein at least one of A 1 and A 2 is a cyano group.
18. The organic electroluminescence device according to claim 16 , wherein A 1 and A 2 , each independently represent a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms or a substituted or unsubstituted aromatic heterocyclic group having 2 to 30 ring carbon atoms.
19. The organic electroluminescence device according to claim 16 , wherein
A 1 represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms and A 2 represents a substituted or unsubstituted aromatic heterocyclic group having 2 to 30 ring carbon atoms or
A 1 represents a substituted or unsubstituted aromatic heterocyclic group having 2 to 30 ring carbon atoms and A 2 , represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms.
20. The organic electroluminescence device according to claim 16 , wherein
Y 1 to Y 4 and Y 13 to Y 16 independently represent C(R),
Y 5 to Y 8 independently represent C(R) or a carbon atom to be bonded to one of Y 9 , to Y 12 ,
Y 9 , to Y 12 independently represent C(R) or a carbon atom to be bonded to one of Y 5 to Y 8 , and
R independently represents a hydrogen atom or a substituent.
21. The organic electroluminescence device according to claim 16 , wherein
one of L 1 and L 2 represents a single bond, and
the other of L 1 and L 2 , is represented by a formula (a) below,
where, in the formula (a), Y 21 to Y 25 each independently represent C(R a ), a nitrogen atom or a carbon atom bonded to L 3 ,
R a independently represents a hydrogen atom or a substituent, the substituent for R a being the same as the substituent for A 1 and A 2 , and
L 3 and L 4 each independently represent: a single bond; a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 30 ring carbon atoms; a substituted or unsubstituted divalent aromatic heterocyclic group having 2 to 30 ring carbon atoms; or a group formed by bonding the above divalent aromatic hydrocarbon group and the above divalent aromatic heterocyclic group.
22. The organic electroluminescence device according to claim 16 , wherein
one of L 1 and L 2 represents a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 30 ring carbon atoms, a substituted or unsubstituted divalent aromatic heterocyclic group having 2 to 30 ring carbon atoms, or a group formed by bonding the substituted or unsubstituted divalent aromatic hydrocarbon group and the substituted or unsubstituted divalent aromatic heterocyclic group, and
the other of L 1 and L 2 , is represented by a formula (a) below,
where, in the formula (a), Y 21 to Y 25 each independently represent C(R a ), a nitrogen atom or a carbon atom bonded to L 3 ,
R a independently represents a hydrogen atom or a substituent, the substituent for R a being the same as the substituent for A 1 and A 2 , and
L 3 and L 4 each independently represent: a single bond; a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 30 ring carbon atoms; a substituted or unsubstituted divalent aromatic heterocyclic group having 2 to 30 ring carbon atoms; or a group formed by bonding the above divalent aromatic hydrocarbon group and the above divalent aromatic heterocyclic group.
23. The organic electroluminescence device according to claim 16 , wherein
at least one of L 1 and L 2 is represented by a formula (a) below,
where, in the formula (a), Y 21 to Y 25 each independently represent C(R a ) or a carbon atom bonded to L 3 ,
R a independently represents a hydrogen atom or a substituent, the substituent for R a being the same as the substituent for A 1 and A 2 , and
L 3 and L 4 each independently represent: a single bond: a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 30 ring carbon atoms: a substituted or unsubstituted divalent aromatic heterocyclic group having 2 to 30 ring carbon atoms; or a group formed by bonding the above divalent aromatic hydrocarbon group and the above divalent aromatic heterocyclic group.
24. The organic electroluminescence device according to claim 16 , wherein
A 1 is a cyano group,
L 1 is represented by a formula (a) below,
where, in the formula (a), Y 21 to Y 25 each independently represent C(R a ), a nitrogen atom or a carbon atom bonded to L 3 ,
R a independently represents a hydrogen atom or a substituent, the substituent for R a being the same as the substituent for A 1 and A 2 , and
L 3 and L 4 each independently represent: a single bond; a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 30 ring carbon atoms; a substituted or unsubstituted divalent aromatic heterocyclic group having 2 to 30 ring carbon atoms; or a group formed by bonding the above divalent aromatic hydrocarbon group and the above divalent aromatic heterocyclic group.
25. The organic electroluminescence device according to claim 24 , wherein
A 2 , is a substituted or unsubstituted aromatic hydrocarbon group having 6 ring carbon atoms,
L 2 , is a single bond,
Y 1 to Y 4 and Y 13 to Y 16 each independently represent C(R),
Y 5 to Y 8 each independently represent C(R) or a carbon atom bonded to one of Y 9 to Y 12 , and
Y 9 , to Y 12 each independently represent C(R) or a carbon atom bonded to one of Y 5 to Y 8 .
26. The organic electroluminescence device according to claim 25 , wherein
the difference ΔST(H1) between the singlet energy EgS(H1) of the first material and the energy gap Eg 77K (H1) at 77K of the first material satisfies formula (4) below:
Δ ST ( H 1)= EgS ( H 1)−Eg 77K ( H 1)<0.2[eV] (4),
a half bandwidth of a photoluminescence spectrum of the first material is 50 nm or more,
the emitting layer does not comprise a heavy-metal complex,
the first material exhibits a delayed fluorescence.
27. The organic electroluminescence device according to claim 16 , wherein
A 1 is a substituted or unsubstituted pyrimidine or a substituted or unsubstituted triazine.
28. The organic electroluminescence device according to claim 27 , wherein
A 2 is a substituted or unsubstituted aromatic hydrocarbon group having 6 ring carbon atoms,
L 1 is a single bond,
L 2 is a single bond,
Y 1 to Y 4 and Y 13 to Y 16 each independently represent C(R),
Y 5 to Y 8 each independently represent C(R) or a carbon atom bonded to one of Y 9 , to Y 12 , and
Y 9 , to Y 12 each independently represent C(R) or a carbon atom bonded to one of Y 5 to Y 8 .
29. The organic electroluminescence device according to claim 28 , wherein
the difference ΔST(H1) between the singlet energy EgS(H1) of the first material and the energy gap Eg 77K (H1) at 77K of the first material satisfies formula (4) below:
Δ ST ( H 1)= EgS ( H 1)−Eg 77K ( H 1)<0.2[eV] (4),
a half bandwidth of a photoluminescence spectrum of the first material is 50 nm or more,
the emitting layer does not comprise a heavy-metal complex,
the first material exhibits a delayed fluorescence.