Light-emitting element, light-emitting device, electronic device, and lighting device
申请人:Semiconductor Energy Laboratory Co., Ltd.
公开号:US11088335B2
公开(公告)日:2021-08-10
Provided is a novel light-emitting element, a light-emitting element with a long lifetime, or a light-emitting element with high emission efficiency. The light-emitting element includes an EL layer between a pair of electrodes. The EL layer includes at least a light-emitting layer containing a fluorescent substance and a host material, a first electron-transport layer containing a first electron-transport material, and a second electron-transport layer containing a second electron-transport material, which are in contact with each other and in this order. The LUMO level of each of the host material and the second electron-transport material is higher than the LUMO level of the first electron-transport material.
本文提供了一种新型发光元件、一种寿命长的发光元件或一种发射效率高的发光元件。该发光元件包括位于一对电极之间的 EL 层。EL 层至少包括一个包含荧光物质和宿主材料的发光层、一个包含第一电子传输材料的第一电子传输层和一个包含第二电子传输材料的第二电子传输层,它们依次相互接触。宿主材料和第二电子传输材料的LUMO电平均高于第一电子传输材料的LUMO电平。