Top emission type organic electroluminescent device, and method for designing same
AssigneeKyulux, Inc.
InventorHayato KAKIZOE
Life of this patent
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Abstract
A top emission type organic electroluminescent device including a light emitting layer containing first to third organic compounds, in which the second organic compound is a delayed fluorescent material having lower ES1 than the first organic compound, and the third organic compound has the lowest ES1 and higher ELUMO and EHOMO than the second organic compound and has a S value of −0.38 or less and a full width at half maximum of 31 nm or less, has a high light emission efficiency.
Claims16
A top emission type organic electroluminescent device comprising a lamination structure including a substrate, a first electrode, a light emitting layer, and a transparent second electrode in this order,
- the light emitting layer containing a first organic compound, a second organic compound, and a third organic compound that satisfy the following expressions (a) to (c),
- the second organic compound being a delayed fluorescent material,
- the third organic compound having an S value of −0.38 or less in the light emitting layer,
- the third organic compound having a full width at half maximum of a light emission spectrum of 31 nm or less:
- E
- S
-
- 1
- (
- 1
- )
- >
- E
- S
-
- 1
- (
- 2
- )
- >
- E
- S
-
- 1
- (
- 3
- )
- (
- a
- )
- E
- LUMO
- (
- 2
- )
- ≤
- E
- LUMO
- (
- 3
- )
- (
- b
- )
- E
- HOMO
- (
- 2
- )
- ≤
- E
- HOMO
- (
- 3
- )
- (
- c
- )
- wherein
- ES1(1) represents lowest excited singlet energy of the first organic compound,
- ES1(2) represents lowest excited singlet energy of the second organic compound,
- ES1(3) represents lowest excited singlet energy of the third organic compound,
- ELUMO(2) represents energy of a LUMO of the second organic compound,
- ELUMO(3) represents energy of a LUMO of the third organic compound,
- EHOMO(2) represents energy of a HOMO of the second organic compound, and
- EHOMO(3) represents energy of a HOMO of the third organic compound.
A method for evaluating a light emission capability of a film containing the first organic compound, the second organic compound, and the third organic compound that satisfy the expressions (a) to (c),
- the method comprising evaluating the light emission capability of the film with an S value of the third organic compound and a full width at half maximum of a light emission spectrum of the third organic compound as indices:
- E
- S
-
- 1
- (
- 1
- )
- >
- E
- S
-
- 1
- (
- 2
- )
- >
- E
- S
-
- 1
- (
- 3
- )
- (
- a
- )
- E
- LUMO
- (
- 2
- )
- ≤
- E
- LUMO
- (
- 3
- )
- (
- b
- )
- E
- HOMO
- (
- 2
- )
- ≤
- E
- HOMO
- (
- 3
- )
- (
- c
- )
- wherein
- ES1(1) represents lowest excited singlet energy of the first organic compound,
- ES1(2) represents lowest excited singlet energy of the second organic compound,
- ES1(3) represents lowest excited singlet energy of the third organic compound,
- ELUMO(2) represents energy of a LUMO of the second organic compound,
- ELUMO(3) represents energy of a LUMO of the third organic compound,
- EHOMO(2) represents energy of a HOMO of the second organic compound, and
- EHOMO(3) represents energy of a HOMO of the third organic compound.
A method for determining a condition suitable for film formation, comprising
- forming a film containing the first organic compound, the second organic compound, and the third organic compound that satisfy the expressions (a) to (c) under one condition,
- measuring an S value and a full width at half maximum of a light emission spectrum of the third organic compound in the formed film,
- repeating once or more an operation including forming a film containing the first organic compound, the second organic compound, and the third organic compound under a condition different from the previous condition, and measuring an S value and a full width at half maximum of a light emission spectrum of the third organic compound in the formed film, and
- evaluating the S value and the full width at half maximum as indices:
- E
- S
-
- 1
- (
- 1
- )
- >
- E
- S
-
- 1
- (
- 2
- )
- >
- E
- S
-
- 1
- (
- 3
- )
- (
- a
- )
- E
- LUMO
- (
- 2
- )
- ≤
- E
- LUMO
- (
- 3
- )
- (
- b
- )
- E
- HOMO
- (
- 2
- )
- ≤
- E
- HOMO
- (
- 3
- )
- (
- c
- )
- wherein
- ES1(1) represents lowest excited singlet energy of the first organic compound,
- ES1(2) represents lowest excited singlet energy of the second organic compound,
- ES1(3) represents lowest excited singlet energy of the third organic compound,
- ELUMO(2) represents energy of a LUMO of the second organic compound,
- ELUMO(3) represents energy of a LUMO of the third organic compound,
- EHOMO(2) represents energy of a HOMO of the second organic compound, and
- EHOMO(3) represents energy of a HOMO of the third organic compound.
Dependencies are inferred from the claim text.