Light-emitting element and display device
AssigneeJapan Display Inc.
InventorNobuto MANAGAKI
Life of this patent
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Abstract
A light-emitting element includes a pair of electrodes, and a light-emitting layer between the pair of electrodes, wherein the light-emitting layer includes a first host material, a second host material, and a first light-emitting material exhibiting thermally activated delayed fluorescence, a concentration of the first host material is greater than a concentration of the second host material in the light-emitting layer, a band gap of the first host material is larger than a band gap of the second host material, a singlet excitation energy level of the first light-emitting material is lower than a singlet excitation energy level of the first host material, and a triplet excitation energy level of the second host material is lower than a triplet excitation energy level of the first host material.
Claims20
A light-emitting element comprising:
- a pair of electrodes;
- and
- a light-emitting layer between the pair of electrodes,
- wherein the light-emitting layer comprises a first host material, a second host material, a first light-emitting material exhibiting thermally activated delayed fluorescence,
- a concentration of the first host material is greater than a concentration of the second host material in the light-emitting layer,
- a band gap of the first host material is larger than a band gap of the second host material,
- a singlet excitation energy level of the first light-emitting material is lower than a singlet excitation energy level of the first host material, and
- a triplet excitation energy level of the second host material is lower than a triplet excitation energy level of the first host material.
A display device comprising:
- a first pixel having a first light-emitting element;
- and
- a second pixel having a second light-emitting element,
- wherein the first light-emitting element has a pair of electrodes, and a first light-emitting layer between the pair of electrodes,
- the first light-emitting layer comprises a first host material, a second host material, and a first light-emitting material exhibiting thermally activated delayed fluorescence,
- the second light-emitting element has the pair of electrodes, and a second light-emitting layer between the pair of electrodes,
- the second light-emitting layer comprises the second host material, and a second light-emitting material having a singlet excitation energy level higher than a singlet excitation energy level of the first light-emitting material,
- a concentration of the first host material is greater than a concentration of the second host material in the first light-emitting layer,
- a band gap of the first host material is larger than a band gap of the second host material, and
- a triplet excitation energy level of the second host material is lower than a triplet excitation energy level of the first host material.
Dependencies are inferred from the claim text.