US 12,114,517 B2
Light-emitting element and light-emitting device
Masanobu Mizusaki, Sakai (JP); and Hiroshi Tsuchiya, Sakai (JP)
Assigned to SHARP KABUSHIKI KAISHA, Sakai (JP)
Appl. No. 17/439,369
Filed by SHARP KABUSHIKI KAISHA, Sakai (JP)
PCT Filed Mar. 22, 2019, PCT No. PCT/JP2019/012256
§ 371(c)(1), (2) Date Sep. 14, 2021,
PCT Pub. No. WO2020/194411, PCT Pub. Date Oct. 1, 2020.
Prior Publication US 2022/0158111 A1, May 19, 2022
Int. Cl. H01L 33/26 (2010.01); H10K 50/11 (2023.01); H10K 50/15 (2023.01); H10K 50/16 (2023.01); H10K 59/122 (2023.01); H10K 71/00 (2023.01); H10K 101/30 (2023.01); H10K 101/40 (2023.01)
CPC H10K 50/11 (2023.02) [H01L 33/26 (2013.01); H10K 50/156 (2023.02); H10K 50/166 (2023.02); H10K 59/122 (2023.02); H10K 71/00 (2023.02); H10K 2101/30 (2023.02); H10K 2101/40 (2023.02)] 14 Claims
OG exemplary drawing
 
1. A light-emitting element comprising:
an anode electrode;
a cathode electrode;
a first hole transport layer;
a second hole transport layer;
a light-emitting layer;
a first electron transport layer; and
a second electron transport layer, wherein
the first hole transport layer, the second hole transport layer, the light-emitting layer, the first electron transport layer, and the second electron transport layer are provided between the anode electrode and the cathode electrode in order from a side closer to the anode electrode,
a value of a lowest unoccupied molecular orbital (LUMO) level of the second hole transport layer is greater than a value of a LUMO level of the light-emitting layer, and a value of a LUMO level of the light-emitting layer is equal to or greater than a value of a LUMO level of the first electron transport layer,
a value of a highest occupied molecular orbital (HOMO) level of the light-emitting layer is greater than a value of a HOMO level of the first electron transport layer,
an energy level difference between the second hole transport layer and the light-emitting layer is greater than an energy level difference between the light-emitting layer and the first electron transport layer in a LUMO level,
an energy level difference between the first electron transport layer and the light-emitting layer is greater than an energy level difference between the light-emitting layer and the second hole transport layer in a HOMO level,
the light-emitting layer is a single layer,
an energy level difference between the light-emitting layer and the first electron transport layer in the LUMO level is not less than 0.0 eV and not greater than 0.15 eV, and
an energy level difference between the light-emitting layer and the second hole transport layer in the HOMO level is not less than 0.0 eV and not greater than 0.15 eV.