US 12,004,359 B2
Light-emitting element, display device, electronic device, and lighting device
Nobuharu Ohsawa, Kanagawa (JP); and Satoshi Seo, Kanagawa (JP)
Assigned to Semiconductor Energy Laboratory Co., Ltd., (JP)
Filed by Semiconductor Energy Laboratory Co., Ltd., Kanagawa-ken (JP)
Filed on Nov. 17, 2022, as Appl. No. 17/989,000.
Application 17/989,000 is a division of application No. 16/542,589, filed on Aug. 16, 2019, granted, now 11,508,926.
Application 16/542,589 is a division of application No. 14/878,376, filed on Oct. 8, 2015, abandoned.
Claims priority of application No. 2014-208543 (JP), filed on Oct. 10, 2014.
Prior Publication US 2023/0094551 A1, Mar. 30, 2023
Int. Cl. H10K 50/11 (2023.01); C09K 11/06 (2006.01); H10K 50/12 (2023.01); H10K 85/60 (2023.01); H10K 101/00 (2023.01); H10K 101/10 (2023.01); H10K 101/30 (2023.01)
CPC H10K 50/11 (2023.02) [C09K 11/06 (2013.01); H10K 50/121 (2023.02); H10K 85/615 (2023.02); H10K 2101/10 (2023.02); H10K 2101/27 (2023.02); H10K 2101/30 (2023.02); H10K 2101/90 (2023.02)] 12 Claims
OG exemplary drawing
 
1. A light-emitting element comprising:
a pair of electrodes; and
an EL layer provided between the pair of electrodes,
wherein the EL layer comprises a light-emitting layer,
wherein the light-emitting layer comprises a host material and a guest material,
wherein the host material comprises a first organic compound and a second organic compound,
wherein an exciplex formed by the first organic compound and the second organic compound is capable of exhibiting thermally activated delayed fluorescence at room temperature,
wherein the guest material is capable of exhibiting fluorescence,
wherein a second triplet excitation energy level of the guest material is higher than or equal to a lowest triplet excitation energy level of the exciplex, and
wherein the lowest triplet excitation energy level of the exciplex is higher than or equal to a lowest triplet excitation energy level of the guest material.